TY  - CONF
AU  - Marinković, Dalibor
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Seidel-Morgenstern, Andreas
AU  - Kienle, Achim
AU  - Petkovska, Menka
PY  - 2024
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/7522
AB  - The continuous industrial chemical processes are typically designed through steady-state conditions. Nevertheless, there is evidence that processes can be intensified by applying optimized forced periodic operation. Possible improvements in reactor performances caused by the implementation of forced periodic operation (FPO) can be successfully evaluated by applying a nonlinear frequency response (NFR) analysis, before experimental investigation. In this study, we will present the results of two case studies based on heterogeneously catalyzed methanol synthesis in a continuous stirred tank reactor (CSTR). The first is an isothermal case, and the second is a more complicated and more realistic, non-isothermal case.
PB  - Stockholm, Sweden : Scanditale AB
C3  - Energy Proceedings
T1  - Evaluation of possible improvements of forced periodically operated reactor in which methanol synthesis takes place – based on the Nonlinear Frequency Response analysis
VL  - 43
IS  - VI
DO  - 10.46855/energy-proceedings-11025
ER  - 

@conference{
author = "Marinković, Dalibor and Nikolić, Daliborka and Seidel, Carsten and Seidel-Morgenstern, Andreas and Kienle, Achim and Petkovska, Menka",
year = "2024",
abstract = "The continuous industrial chemical processes are typically designed through steady-state conditions. Nevertheless, there is evidence that processes can be intensified by applying optimized forced periodic operation. Possible improvements in reactor performances caused by the implementation of forced periodic operation (FPO) can be successfully evaluated by applying a nonlinear frequency response (NFR) analysis, before experimental investigation. In this study, we will present the results of two case studies based on heterogeneously catalyzed methanol synthesis in a continuous stirred tank reactor (CSTR). The first is an isothermal case, and the second is a more complicated and more realistic, non-isothermal case.",
publisher = "Stockholm, Sweden : Scanditale AB",
journal = "Energy Proceedings",
title = "Evaluation of possible improvements of forced periodically operated reactor in which methanol synthesis takes place – based on the Nonlinear Frequency Response analysis",
volume = "43",
number = "VI",
doi = "10.46855/energy-proceedings-11025"
}

Marinković, D., Nikolić, D., Seidel, C., Seidel-Morgenstern, A., Kienle, A.,& Petkovska, M.. (2024). Evaluation of possible improvements of forced periodically operated reactor in which methanol synthesis takes place – based on the Nonlinear Frequency Response analysis. in Energy Proceedings
Stockholm, Sweden : Scanditale AB., 43(VI).
https://doi.org/10.46855/energy-proceedings-11025

Marinković D, Nikolić D, Seidel C, Seidel-Morgenstern A, Kienle A, Petkovska M. Evaluation of possible improvements of forced periodically operated reactor in which methanol synthesis takes place – based on the Nonlinear Frequency Response analysis. in Energy Proceedings. 2024;43(VI).
doi:10.46855/energy-proceedings-11025 .

Marinković, Dalibor, Nikolić, Daliborka, Seidel, Carsten, Seidel-Morgenstern, Andreas, Kienle, Achim, Petkovska, Menka, "Evaluation of possible improvements of forced periodically operated reactor in which methanol synthesis takes place – based on the Nonlinear Frequency Response analysis" in Energy Proceedings, 43, no. VI (2024),
https://doi.org/10.46855/energy-proceedings-11025 . .

TY  - JOUR
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Felischak, Matthias
AU  - Miličić, Tamara
AU  - Kienle, Achim
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4813
AB  - In this two-part paper a comprehensive study of the potential to improve performance criteria of a methanol synthesis reactor through forced periodical operations is presented. The study uses the Nonlinear Frequency Response method, a powerful analytical and approximate tool which gives an answer whether and under which conditions certain periodic operation would lead to improvement of process performance. To demonstrate the method, isothermal and isobaric methanol synthesis in a lab-scale CSTR is considered. In Part I, the analysis is performed for single input modulations. Partial pressures of each reactant in the feed stream and the total inlet volumetric flow-rate are considered as possible modulated inputs. The results show that modulations of single inputs essentially do not provide potential for significant improvements. In Part II, the study will be extended to analysis of periodic operations with simultaneous modulations of two inputs and conditions offering significant performance enhancements will be identified.
PB  - Elsevier
T2  - Chemical Engineering Science
T1  - Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations
VL  - 248
SP  - 117134
DO  - 10.1016/j.ces.2021.117134
ER  - 

@article{
author = "Nikolić, Daliborka and Seidel, Carsten and Felischak, Matthias and Miličić, Tamara and Kienle, Achim and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2022",
abstract = "In this two-part paper a comprehensive study of the potential to improve performance criteria of a methanol synthesis reactor through forced periodical operations is presented. The study uses the Nonlinear Frequency Response method, a powerful analytical and approximate tool which gives an answer whether and under which conditions certain periodic operation would lead to improvement of process performance. To demonstrate the method, isothermal and isobaric methanol synthesis in a lab-scale CSTR is considered. In Part I, the analysis is performed for single input modulations. Partial pressures of each reactant in the feed stream and the total inlet volumetric flow-rate are considered as possible modulated inputs. The results show that modulations of single inputs essentially do not provide potential for significant improvements. In Part II, the study will be extended to analysis of periodic operations with simultaneous modulations of two inputs and conditions offering significant performance enhancements will be identified.",
publisher = "Elsevier",
journal = "Chemical Engineering Science",
title = "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations",
volume = "248",
pages = "117134",
doi = "10.1016/j.ces.2021.117134"
}

Nikolić, D., Seidel, C., Felischak, M., Miličić, T., Kienle, A., Seidel-Morgenstern, A.,& Petkovska, M.. (2022). Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations. in Chemical Engineering Science
Elsevier., 248, 117134.
https://doi.org/10.1016/j.ces.2021.117134

Nikolić D, Seidel C, Felischak M, Miličić T, Kienle A, Seidel-Morgenstern A, Petkovska M. Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations. in Chemical Engineering Science. 2022;248:117134.
doi:10.1016/j.ces.2021.117134 .

Nikolić, Daliborka, Seidel, Carsten, Felischak, Matthias, Miličić, Tamara, Kienle, Achim, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations" in Chemical Engineering Science, 248 (2022):117134,
https://doi.org/10.1016/j.ces.2021.117134 . .

TY  - JOUR
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Felischak, Matthias
AU  - Miličić, Tamara
AU  - Kienle, Achim
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4816
AB  - The analysis of the potential to improve performance of a methanol synthesis reactor through forced periodical operations by Nonlinear Frequency Response method is presented. The methanol synthesis in an isothermal and isobaric lab-scale CSTR is considered. First, the analysis was performed for single input modulations (in Part I), which showed that significant improvements can't be achieved. Here, the study is extended to analysis of simultaneous modulations of two inputs. All possible input combinations (6 cases) are analysed and the optimal forcing parameters, maximizing the time-average methanol production, were determined. For all combinations the improvement is possible, but for some cases it is not significant. The highest improvement is predicted for simultaneous modulation of the inlet partial pressure of CO and the inlet volumetric flow rate. This case, for which it is possible to achieve up to 33.51 % of methanol production, is analysed it detail and optimized using multi-objective optimization.
PB  - Elsevier
T2  - Chemical Engineering Science
T1  - Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs
VL  - 248
SP  - 117133
DO  - 10.1016/j.ces.2021.117133
ER  - 

@article{
author = "Nikolić, Daliborka and Seidel, Carsten and Felischak, Matthias and Miličić, Tamara and Kienle, Achim and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2022",
abstract = "The analysis of the potential to improve performance of a methanol synthesis reactor through forced periodical operations by Nonlinear Frequency Response method is presented. The methanol synthesis in an isothermal and isobaric lab-scale CSTR is considered. First, the analysis was performed for single input modulations (in Part I), which showed that significant improvements can't be achieved. Here, the study is extended to analysis of simultaneous modulations of two inputs. All possible input combinations (6 cases) are analysed and the optimal forcing parameters, maximizing the time-average methanol production, were determined. For all combinations the improvement is possible, but for some cases it is not significant. The highest improvement is predicted for simultaneous modulation of the inlet partial pressure of CO and the inlet volumetric flow rate. This case, for which it is possible to achieve up to 33.51 % of methanol production, is analysed it detail and optimized using multi-objective optimization.",
publisher = "Elsevier",
journal = "Chemical Engineering Science",
title = "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs",
volume = "248",
pages = "117133",
doi = "10.1016/j.ces.2021.117133"
}

Nikolić, D., Seidel, C., Felischak, M., Miličić, T., Kienle, A., Seidel-Morgenstern, A.,& Petkovska, M.. (2022). Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs. in Chemical Engineering Science
Elsevier., 248, 117133.
https://doi.org/10.1016/j.ces.2021.117133

Nikolić D, Seidel C, Felischak M, Miličić T, Kienle A, Seidel-Morgenstern A, Petkovska M. Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs. in Chemical Engineering Science. 2022;248:117133.
doi:10.1016/j.ces.2021.117133 .

Nikolić, Daliborka, Seidel, Carsten, Felischak, Matthias, Miličić, Tamara, Kienle, Achim, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs" in Chemical Engineering Science, 248 (2022):117133,
https://doi.org/10.1016/j.ces.2021.117133 . .

TY  - JOUR
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Felischak, Matthias
AU  - Miličić, Tamara
AU  - Kienle, Achim
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4819
AB  - In this two-part paper a comprehensive study of the potential to improve performance criteria of a methanol synthesis reactor through forced periodical operations is presented. The study uses the Nonlinear Frequency Response method, a powerful analytical and approximate tool which gives an answer whether and under which conditions certain periodic operation would lead to improvement of process performance. To demonstrate the method, isothermal and isobaric methanol synthesis in a lab-scale CSTR is considered. In Part I, the analysis is performed for single input modulations. Partial pressures of each reactant in the feed stream and the total inlet volumetric flow-rate are considered as possible modulated inputs. The results show that modulations of single inputs essentially do not provide potential for significant improvements. In Part II, the study will be extended to analysis of periodic operations with simultaneous modulations of two inputs and conditions offering significant performance enhancements will be identified.
PB  - Elsevier
T2  - Chemical Engineering Science
T1  - Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations
VL  - 248
SP  - 117134
DO  - 10.1016/j.ces.2021.117134
ER  - 

@article{
author = "Nikolić, Daliborka and Seidel, Carsten and Felischak, Matthias and Miličić, Tamara and Kienle, Achim and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2022",
abstract = "In this two-part paper a comprehensive study of the potential to improve performance criteria of a methanol synthesis reactor through forced periodical operations is presented. The study uses the Nonlinear Frequency Response method, a powerful analytical and approximate tool which gives an answer whether and under which conditions certain periodic operation would lead to improvement of process performance. To demonstrate the method, isothermal and isobaric methanol synthesis in a lab-scale CSTR is considered. In Part I, the analysis is performed for single input modulations. Partial pressures of each reactant in the feed stream and the total inlet volumetric flow-rate are considered as possible modulated inputs. The results show that modulations of single inputs essentially do not provide potential for significant improvements. In Part II, the study will be extended to analysis of periodic operations with simultaneous modulations of two inputs and conditions offering significant performance enhancements will be identified.",
publisher = "Elsevier",
journal = "Chemical Engineering Science",
title = "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations",
volume = "248",
pages = "117134",
doi = "10.1016/j.ces.2021.117134"
}

Nikolić, D., Seidel, C., Felischak, M., Miličić, T., Kienle, A., Seidel-Morgenstern, A.,& Petkovska, M.. (2022). Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations. in Chemical Engineering Science
Elsevier., 248, 117134.
https://doi.org/10.1016/j.ces.2021.117134

Nikolić D, Seidel C, Felischak M, Miličić T, Kienle A, Seidel-Morgenstern A, Petkovska M. Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations. in Chemical Engineering Science. 2022;248:117134.
doi:10.1016/j.ces.2021.117134 .

Nikolić, Daliborka, Seidel, Carsten, Felischak, Matthias, Miličić, Tamara, Kienle, Achim, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part I Single input modulations" in Chemical Engineering Science, 248 (2022):117134,
https://doi.org/10.1016/j.ces.2021.117134 . .

TY  - JOUR
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Felischak, Matthias
AU  - Miličić, Tamara
AU  - Kienle, Achim
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4820
AB  - The analysis of the potential to improve performance of a methanol synthesis reactor through forced periodical operations by Nonlinear Frequency Response method is presented. The methanol synthesis in an isothermal and isobaric lab-scale CSTR is considered. First, the analysis was performed for single input modulations (in Part I), which showed that significant improvements can't be achieved. Here, the study is extended to analysis of simultaneous modulations of two inputs. All possible input combinations (6 cases) are analysed and the optimal forcing parameters, maximizing the time-average methanol production, were determined. For all combinations the improvement is possible, but for some cases it is not significant. The highest improvement is predicted for simultaneous modulation of the inlet partial pressure of CO and the inlet volumetric flow rate. This case, for which it is possible to achieve up to 33.51 % of methanol production, is analysed it detail and optimized using multi-objective optimization.
PB  - Elsevier
T2  - Chemical Engineering Science
T1  - Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs
VL  - 248
SP  - 117133
DO  - 10.1016/j.ces.2021.117133
ER  - 

@article{
author = "Nikolić, Daliborka and Seidel, Carsten and Felischak, Matthias and Miličić, Tamara and Kienle, Achim and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2022",
abstract = "The analysis of the potential to improve performance of a methanol synthesis reactor through forced periodical operations by Nonlinear Frequency Response method is presented. The methanol synthesis in an isothermal and isobaric lab-scale CSTR is considered. First, the analysis was performed for single input modulations (in Part I), which showed that significant improvements can't be achieved. Here, the study is extended to analysis of simultaneous modulations of two inputs. All possible input combinations (6 cases) are analysed and the optimal forcing parameters, maximizing the time-average methanol production, were determined. For all combinations the improvement is possible, but for some cases it is not significant. The highest improvement is predicted for simultaneous modulation of the inlet partial pressure of CO and the inlet volumetric flow rate. This case, for which it is possible to achieve up to 33.51 % of methanol production, is analysed it detail and optimized using multi-objective optimization.",
publisher = "Elsevier",
journal = "Chemical Engineering Science",
title = "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs",
volume = "248",
pages = "117133",
doi = "10.1016/j.ces.2021.117133"
}

Nikolić, D., Seidel, C., Felischak, M., Miličić, T., Kienle, A., Seidel-Morgenstern, A.,& Petkovska, M.. (2022). Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs. in Chemical Engineering Science
Elsevier., 248, 117133.
https://doi.org/10.1016/j.ces.2021.117133

Nikolić D, Seidel C, Felischak M, Miličić T, Kienle A, Seidel-Morgenstern A, Petkovska M. Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs. in Chemical Engineering Science. 2022;248:117133.
doi:10.1016/j.ces.2021.117133 .

Nikolić, Daliborka, Seidel, Carsten, Felischak, Matthias, Miličić, Tamara, Kienle, Achim, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Forced periodic operations of a chemical reactor for methanol synthesis – The search for the best scenario based on Nonlinear Frequency Response Method. Part II Simultaneous modulation of two inputs" in Chemical Engineering Science, 248 (2022):117133,
https://doi.org/10.1016/j.ces.2021.117133 . .

TY  - CONF
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Felischak, Matthias
AU  - Marinković, Dalibor
AU  - Kienle, Achim
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4926
AB  - Forced periodic operations, as one way of Process Intensification, can be used in order to achieve better performances of chemical reactors, in comparison to conventional steady-state operation. In this study the Nonlinear Frequency Response (NFR) method, a powerful analytical and approximate tool which gives an answer whether and under which conditions certain periodic operation would lead to improvement of process performance was used. The analysis was done for the methanol synthesis using a standard Cu/ZnO catalyst performed in an isothermal and isobaric lab-scale CSTR. At first the single input modulations were analysed. The inputs considered for periodic modulation are: partial pressures of each reactant in the feed stream and the total volumetric inlet flow-rate. The objective was to maximize the mean molar outlet flow-rate of methanol. The specific forcing parameters were optimized. The results of the NFR analysis showed that modulations of single inputs do not provide potential for significant improvements. 
The study was extended to analysis of periodic operations with simultaneous modulations of two inputs. Six possible input combinations were analysed and the optimal forcing parameters which maximizing again the time-average methanol production were determined. For all combinations an improvement is possible, but for some cases it was found to be not significant. However, significant 
improvements are predicted for a) simultaneous modulation of the partial pressure of CO2 in the feed steam and the volumetric inlet flow-rate and b) simultaneous modulation of the partial pressure of hydrogen (H2) and the volumetric inlet flow-rate [1, 2]. The highest improvement could be achieved for 
simultaneous modulation of the inlet partial pressure of CO and the inlet volumetric flow rate.
PB  - The Wilhelm und Else Heraeus-Stiftung, Germany
C3  - Booklet with abstracts - 758. WE-Heraeus-Seminar, From Wind and Solar Energy to Chemical Energy Storage: Understanding and Engineering Catalysis under Dynamic Conditions
T1  - Possible improvement of methanol synthesis exploiting forced periodic operation: Analysis using the Nonlinear Frequency Responce Method
SP  - 75
UR  - https://hdl.handle.net/21.15107/rcub_cer_4926
ER  - 

@conference{
author = "Nikolić, Daliborka and Seidel, Carsten and Felischak, Matthias and Marinković, Dalibor and Kienle, Achim and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2022",
abstract = "Forced periodic operations, as one way of Process Intensification, can be used in order to achieve better performances of chemical reactors, in comparison to conventional steady-state operation. In this study the Nonlinear Frequency Response (NFR) method, a powerful analytical and approximate tool which gives an answer whether and under which conditions certain periodic operation would lead to improvement of process performance was used. The analysis was done for the methanol synthesis using a standard Cu/ZnO catalyst performed in an isothermal and isobaric lab-scale CSTR. At first the single input modulations were analysed. The inputs considered for periodic modulation are: partial pressures of each reactant in the feed stream and the total volumetric inlet flow-rate. The objective was to maximize the mean molar outlet flow-rate of methanol. The specific forcing parameters were optimized. The results of the NFR analysis showed that modulations of single inputs do not provide potential for significant improvements. 
The study was extended to analysis of periodic operations with simultaneous modulations of two inputs. Six possible input combinations were analysed and the optimal forcing parameters which maximizing again the time-average methanol production were determined. For all combinations an improvement is possible, but for some cases it was found to be not significant. However, significant 
improvements are predicted for a) simultaneous modulation of the partial pressure of CO2 in the feed steam and the volumetric inlet flow-rate and b) simultaneous modulation of the partial pressure of hydrogen (H2) and the volumetric inlet flow-rate [1, 2]. The highest improvement could be achieved for 
simultaneous modulation of the inlet partial pressure of CO and the inlet volumetric flow rate.",
publisher = "The Wilhelm und Else Heraeus-Stiftung, Germany",
journal = "Booklet with abstracts - 758. WE-Heraeus-Seminar, From Wind and Solar Energy to Chemical Energy Storage: Understanding and Engineering Catalysis under Dynamic Conditions",
title = "Possible improvement of methanol synthesis exploiting forced periodic operation: Analysis using the Nonlinear Frequency Responce Method",
pages = "75",
url = "https://hdl.handle.net/21.15107/rcub_cer_4926"
}

Nikolić, D., Seidel, C., Felischak, M., Marinković, D., Kienle, A., Seidel-Morgenstern, A.,& Petkovska, M.. (2022). Possible improvement of methanol synthesis exploiting forced periodic operation: Analysis using the Nonlinear Frequency Responce Method. in Booklet with abstracts - 758. WE-Heraeus-Seminar, From Wind and Solar Energy to Chemical Energy Storage: Understanding and Engineering Catalysis under Dynamic Conditions
The Wilhelm und Else Heraeus-Stiftung, Germany., 75.
https://hdl.handle.net/21.15107/rcub_cer_4926

Nikolić D, Seidel C, Felischak M, Marinković D, Kienle A, Seidel-Morgenstern A, Petkovska M. Possible improvement of methanol synthesis exploiting forced periodic operation: Analysis using the Nonlinear Frequency Responce Method. in Booklet with abstracts - 758. WE-Heraeus-Seminar, From Wind and Solar Energy to Chemical Energy Storage: Understanding and Engineering Catalysis under Dynamic Conditions. 2022;:75.
https://hdl.handle.net/21.15107/rcub_cer_4926 .

Nikolić, Daliborka, Seidel, Carsten, Felischak, Matthias, Marinković, Dalibor, Kienle, Achim, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Possible improvement of methanol synthesis exploiting forced periodic operation: Analysis using the Nonlinear Frequency Responce Method" in Booklet with abstracts - 758. WE-Heraeus-Seminar, From Wind and Solar Energy to Chemical Energy Storage: Understanding and Engineering Catalysis under Dynamic Conditions (2022):75,
https://hdl.handle.net/21.15107/rcub_cer_4926 .

TY  - JOUR
AU  - Felischak, Matthias
AU  - Kaps, Lothar
AU  - Hamel, Christof
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Seidel-Morgenstern, Andreas
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5415
AB  - The authors regret that there was an error in formula (19), which was not detected by us in the final proof. The correct form of equation (19) used to calculate the results presented in Felischak et al., (2020), is: [Formula presented] The authors would like to apologise for any inconvenience caused.
PB  - Elsevier
T2  - Chemical Engineering Journal
T1  - Corrigendum to “Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate” [Chem. Eng. J. 410 (2021) 128197]
VL  - 430
SP  - 132930
DO  - 10.1016/j.cej.2021.132930
ER  - 

@article{
author = "Felischak, Matthias and Kaps, Lothar and Hamel, Christof and Nikolić, Daliborka and Petkovska, Menka and Seidel-Morgenstern, Andreas",
year = "2022",
abstract = "The authors regret that there was an error in formula (19), which was not detected by us in the final proof. The correct form of equation (19) used to calculate the results presented in Felischak et al., (2020), is: [Formula presented] The authors would like to apologise for any inconvenience caused.",
publisher = "Elsevier",
journal = "Chemical Engineering Journal",
title = "Corrigendum to “Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate” [Chem. Eng. J. 410 (2021) 128197]",
volume = "430",
pages = "132930",
doi = "10.1016/j.cej.2021.132930"
}

Felischak, M., Kaps, L., Hamel, C., Nikolić, D., Petkovska, M.,& Seidel-Morgenstern, A.. (2022). Corrigendum to “Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate” [Chem. Eng. J. 410 (2021) 128197]. in Chemical Engineering Journal
Elsevier., 430, 132930.
https://doi.org/10.1016/j.cej.2021.132930

Felischak M, Kaps L, Hamel C, Nikolić D, Petkovska M, Seidel-Morgenstern A. Corrigendum to “Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate” [Chem. Eng. J. 410 (2021) 128197]. in Chemical Engineering Journal. 2022;430:132930.
doi:10.1016/j.cej.2021.132930 .

Felischak, Matthias, Kaps, Lothar, Hamel, Christof, Nikolić, Daliborka, Petkovska, Menka, Seidel-Morgenstern, Andreas, "Corrigendum to “Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate” [Chem. Eng. J. 410 (2021) 128197]" in Chemical Engineering Journal, 430 (2022):132930,
https://doi.org/10.1016/j.cej.2021.132930 . .

TY  - JOUR
AU  - Seidel, Carsten
AU  - Nikolić, Daliborka
AU  - Felischak, Matthias
AU  - Petkovska, Menka
AU  - Seidel-Morgenstern, Andreas
AU  - Kienle, Achim
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5623
AB  - Methanol synthesis from synthesis gas with heterogeneous Cu/ZnO/Al2O3 catalysts in an isothermal gradientless reactor is described. In a theoretical study, the potential of forced periodic operation (FPO) for improving reactor performance in terms of methanol production rate and methanol yield is explored. The approach is based on a detailed kinetic model and combines nonlinear frequency response (NFR) analysis with rigorous numerical multi-objective optimization. Optimal steady-state operation is compared with optimal forced periodic operation for a given benchmark problem with and without inert nitrogen in the feed. Further, the significant influence of the saturation capacity of the solid phase on the dynamic behavior in response to step changes and periodic input modulations is studied.
PB  - Wiley
T2  - Chemical Engineering & Technology
T1  - Forced Periodic Operation of Methanol Synthesis in an Isothermal Gradientless Reactor
VL  - 45
IS  - 12
SP  - 2261
EP  - 2272
DO  - 10.1002/ceat.202200286
ER  - 

@article{
author = "Seidel, Carsten and Nikolić, Daliborka and Felischak, Matthias and Petkovska, Menka and Seidel-Morgenstern, Andreas and Kienle, Achim",
year = "2022",
abstract = "Methanol synthesis from synthesis gas with heterogeneous Cu/ZnO/Al2O3 catalysts in an isothermal gradientless reactor is described. In a theoretical study, the potential of forced periodic operation (FPO) for improving reactor performance in terms of methanol production rate and methanol yield is explored. The approach is based on a detailed kinetic model and combines nonlinear frequency response (NFR) analysis with rigorous numerical multi-objective optimization. Optimal steady-state operation is compared with optimal forced periodic operation for a given benchmark problem with and without inert nitrogen in the feed. Further, the significant influence of the saturation capacity of the solid phase on the dynamic behavior in response to step changes and periodic input modulations is studied.",
publisher = "Wiley",
journal = "Chemical Engineering & Technology",
title = "Forced Periodic Operation of Methanol Synthesis in an Isothermal Gradientless Reactor",
volume = "45",
number = "12",
pages = "2261-2272",
doi = "10.1002/ceat.202200286"
}

Seidel, C., Nikolić, D., Felischak, M., Petkovska, M., Seidel-Morgenstern, A.,& Kienle, A.. (2022). Forced Periodic Operation of Methanol Synthesis in an Isothermal Gradientless Reactor. in Chemical Engineering & Technology
Wiley., 45(12), 2261-2272.
https://doi.org/10.1002/ceat.202200286

Seidel C, Nikolić D, Felischak M, Petkovska M, Seidel-Morgenstern A, Kienle A. Forced Periodic Operation of Methanol Synthesis in an Isothermal Gradientless Reactor. in Chemical Engineering & Technology. 2022;45(12):2261-2272.
doi:10.1002/ceat.202200286 .

Seidel, Carsten, Nikolić, Daliborka, Felischak, Matthias, Petkovska, Menka, Seidel-Morgenstern, Andreas, Kienle, Achim, "Forced Periodic Operation of Methanol Synthesis in an Isothermal Gradientless Reactor" in Chemical Engineering & Technology, 45, no. 12 (2022):2261-2272,
https://doi.org/10.1002/ceat.202200286 . .

TY  - CONF
AU  - Kaps, Lothar
AU  - Seidel, Carsten
AU  - Marinković, Dalibor
AU  - Kienle, Achim
AU  - Seidel-Morgenstern, Andreas
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
PY  - 2022
UR  - https://dechema.de/react_hmt_2022.html
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6314
AB  - Continuous chemical processes are typically designed to operate under steady state 
conditions. However, there is strong evidence that an optimized forced periodic 
operation possesses the potential to improve process performance [1]. More
demonstration examples are needed to promote such advanced concepts.
In this contribution we will present results for two case studies. The first reaction 
investigated is the liquid phase hydrolysis of acetic anhydride performed in an adiabatic 
continuous stirred tank reactor (CSTR). The second examples is the heterogeneously 
catalysed gas phase synthesis of methanol performed in an isothermal and isobaric 
CSTR. Our theoretical analysis exploits independently determined kinetic models of 
these reactions [2, 3]. Besides performing numerical process simulations the Nonlinear 
Frequency Response (NFR) method [4] is used. The magnitude of possible process 
improvements depends on the applied strategy of forced periodic operation. Besides 
the input to be perturbed (concentration, flowrate, temperature, …), the forcing 
frequency and the forcing amplitude as well as the shape of the input modulation are
of relevance. In this contribution we will compare the input modulated as harmonic
(Fig 1a) and as a square wave function (“bang-bang”, Fig 1b). In order to use the NFR 
method for the latter input function an approximation via Fourier series is applied [5, 6].
The results reveal improvements of easier to practically implement square wave inputs
for both examples considered, compared to harmonic modulation of inputs [5, 6].
PB  - DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V. (Society for Chemical Engineering and Biotechnology)
C3  - Book of abstracts - Annual Meeting on Reaction Engineering and ProcessNet Subject Division Heat and Mass Transfer 2022, 18 – 20 July 2022  Congress Center Würzburg, Germany
T1  - Evaluating the shape of input pertubation for forced periodic operation
SP  - 177
EP  - 178
UR  - https://hdl.handle.net/21.15107/rcub_cer_6314
ER  - 

@conference{
author = "Kaps, Lothar and Seidel, Carsten and Marinković, Dalibor and Kienle, Achim and Seidel-Morgenstern, Andreas and Nikolić, Daliborka and Petkovska, Menka",
year = "2022",
abstract = "Continuous chemical processes are typically designed to operate under steady state 
conditions. However, there is strong evidence that an optimized forced periodic 
operation possesses the potential to improve process performance [1]. More
demonstration examples are needed to promote such advanced concepts.
In this contribution we will present results for two case studies. The first reaction 
investigated is the liquid phase hydrolysis of acetic anhydride performed in an adiabatic 
continuous stirred tank reactor (CSTR). The second examples is the heterogeneously 
catalysed gas phase synthesis of methanol performed in an isothermal and isobaric 
CSTR. Our theoretical analysis exploits independently determined kinetic models of 
these reactions [2, 3]. Besides performing numerical process simulations the Nonlinear 
Frequency Response (NFR) method [4] is used. The magnitude of possible process 
improvements depends on the applied strategy of forced periodic operation. Besides 
the input to be perturbed (concentration, flowrate, temperature, …), the forcing 
frequency and the forcing amplitude as well as the shape of the input modulation are
of relevance. In this contribution we will compare the input modulated as harmonic
(Fig 1a) and as a square wave function (“bang-bang”, Fig 1b). In order to use the NFR 
method for the latter input function an approximation via Fourier series is applied [5, 6].
The results reveal improvements of easier to practically implement square wave inputs
for both examples considered, compared to harmonic modulation of inputs [5, 6].",
publisher = "DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V. (Society for Chemical Engineering and Biotechnology)",
journal = "Book of abstracts - Annual Meeting on Reaction Engineering and ProcessNet Subject Division Heat and Mass Transfer 2022, 18 – 20 July 2022  Congress Center Würzburg, Germany",
title = "Evaluating the shape of input pertubation for forced periodic operation",
pages = "177-178",
url = "https://hdl.handle.net/21.15107/rcub_cer_6314"
}

Kaps, L., Seidel, C., Marinković, D., Kienle, A., Seidel-Morgenstern, A., Nikolić, D.,& Petkovska, M.. (2022). Evaluating the shape of input pertubation for forced periodic operation. in Book of abstracts - Annual Meeting on Reaction Engineering and ProcessNet Subject Division Heat and Mass Transfer 2022, 18 – 20 July 2022  Congress Center Würzburg, Germany
DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V. (Society for Chemical Engineering and Biotechnology)., 177-178.
https://hdl.handle.net/21.15107/rcub_cer_6314

Kaps L, Seidel C, Marinković D, Kienle A, Seidel-Morgenstern A, Nikolić D, Petkovska M. Evaluating the shape of input pertubation for forced periodic operation. in Book of abstracts - Annual Meeting on Reaction Engineering and ProcessNet Subject Division Heat and Mass Transfer 2022, 18 – 20 July 2022  Congress Center Würzburg, Germany. 2022;:177-178.
https://hdl.handle.net/21.15107/rcub_cer_6314 .

Kaps, Lothar, Seidel, Carsten, Marinković, Dalibor, Kienle, Achim, Seidel-Morgenstern, Andreas, Nikolić, Daliborka, Petkovska, Menka, "Evaluating the shape of input pertubation for forced periodic operation" in Book of abstracts - Annual Meeting on Reaction Engineering and ProcessNet Subject Division Heat and Mass Transfer 2022, 18 – 20 July 2022  Congress Center Würzburg, Germany (2022):177-178,
https://hdl.handle.net/21.15107/rcub_cer_6314 .

TY  - JOUR
AU  - Felischak, Matthias
AU  - Lothar, Kaps
AU  - Christof, Hamel
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Seidel-Morgenstern, Andreas
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4139
AB  - It is well known, that forced periodic operation possesses the potential for process improvements. Nevertheless, only a small number of applications is reported, due to complex realization, limited predictability and high inertia of larger units. Nonlinear frequency response (NFR) analysis has proven to predict efficiently time-averaged performance of reactor effluent streams originating from forced periodic changes of one or several input(s).
Focus of this paper was an experimental demonstration of forced periodic operation applied to the hydrolysis of acetic anhydride carried out in an adiabatic CSTR. Theoretical results provided a guideline for experiments exploiting simultaneous sinusoidal modulations of the anhydride inlet concentration and the total volumetric flow-rate. Influences of the forcing parameters (amplitudes and the phase difference) were also studied. Confirming the predictions of NFR analysis a significantly higher time-averaged product yields were experimentally achieved compared to conventional steady-state operation with simultaneous modulation of two inputs using an
optimized phase shift.
PB  - Elsevier
T2  - Chemical Engineering Journal
T1  - Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate
VL  - 410
IS  - 128197
DO  - 10.1016/j.cej.2020.128197
ER  - 

@article{
author = "Felischak, Matthias and Lothar, Kaps and Christof, Hamel and Nikolić, Daliborka and Petkovska, Menka and Seidel-Morgenstern, Andreas",
year = "2021",
abstract = "It is well known, that forced periodic operation possesses the potential for process improvements. Nevertheless, only a small number of applications is reported, due to complex realization, limited predictability and high inertia of larger units. Nonlinear frequency response (NFR) analysis has proven to predict efficiently time-averaged performance of reactor effluent streams originating from forced periodic changes of one or several input(s).
Focus of this paper was an experimental demonstration of forced periodic operation applied to the hydrolysis of acetic anhydride carried out in an adiabatic CSTR. Theoretical results provided a guideline for experiments exploiting simultaneous sinusoidal modulations of the anhydride inlet concentration and the total volumetric flow-rate. Influences of the forcing parameters (amplitudes and the phase difference) were also studied. Confirming the predictions of NFR analysis a significantly higher time-averaged product yields were experimentally achieved compared to conventional steady-state operation with simultaneous modulation of two inputs using an
optimized phase shift.",
publisher = "Elsevier",
journal = "Chemical Engineering Journal",
title = "Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate",
volume = "410",
number = "128197",
doi = "10.1016/j.cej.2020.128197"
}

Felischak, M., Lothar, K., Christof, H., Nikolić, D., Petkovska, M.,& Seidel-Morgenstern, A.. (2021). Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate. in Chemical Engineering Journal
Elsevier., 410(128197).
https://doi.org/10.1016/j.cej.2020.128197

Felischak M, Lothar K, Christof H, Nikolić D, Petkovska M, Seidel-Morgenstern A. Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate. in Chemical Engineering Journal. 2021;410(128197).
doi:10.1016/j.cej.2020.128197 .

Felischak, Matthias, Lothar, Kaps, Christof, Hamel, Nikolić, Daliborka, Petkovska, Menka, Seidel-Morgenstern, Andreas, "Analysis and experimental demonstration of forced periodic operation of an adiabatic stirred tank reactor: Simultaneous modulation of inlet concentration and total flow-rate" in Chemical Engineering Journal, 410, no. 128197 (2021),
https://doi.org/10.1016/j.cej.2020.128197 . .

TY  - JOUR
AU  - Seidel, Carsten
AU  - Nikolić, Daliborka
AU  - Felischak, Matthias
AU  - Petkovska, Menka
AU  - Seidel-Morgenstern, Andreas
AU  - Kienle, Achim
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4827
AB  - Traditionally, methanol is produced in large amounts from synthesis gas with heterogeneous Cu/ZnO/Al2O3 catalysts under steady state conditions. In this paper, the potential of alternative forced periodic operation modes is studied using numerical optimization. The focus is a well-mixed isothermal reactor with two periodic inputs, namely, CO concentration in the feed and total feed flow rate. Exploiting a detailed kinetic model which also describes the dynamics of the catalyst, a sequential NLP optimization approach is applied to compare optimal steady state solutions with optimal periodic regimes. Periodic solutions are calculated using dynamic optimization with a periodicity constraint. The NLP optimization is embedded in a multi-objective optimization framework to optimize the process with respect to two objective functions and generate the corresponding Pareto fronts. The first objective is the methanol outlet flow rate. The second objective is the methanol yield based on the total carbon in the feed. Additional constraints arising from the complex methanol reaction and the practical limitations are introduced step by step. The results show that significant improvements for both objective functions are possible through periodic forcing of the two inputs considered here.
PB  - MDPI
T2  - Processes
T1  - Optimization of Methanol Synthesis under Forced Periodic Operation
VL  - 9
IS  - 5
SP  - 872
DO  - 10.3390/pr9050872
ER  - 

@article{
author = "Seidel, Carsten and Nikolić, Daliborka and Felischak, Matthias and Petkovska, Menka and Seidel-Morgenstern, Andreas and Kienle, Achim",
year = "2021",
abstract = "Traditionally, methanol is produced in large amounts from synthesis gas with heterogeneous Cu/ZnO/Al2O3 catalysts under steady state conditions. In this paper, the potential of alternative forced periodic operation modes is studied using numerical optimization. The focus is a well-mixed isothermal reactor with two periodic inputs, namely, CO concentration in the feed and total feed flow rate. Exploiting a detailed kinetic model which also describes the dynamics of the catalyst, a sequential NLP optimization approach is applied to compare optimal steady state solutions with optimal periodic regimes. Periodic solutions are calculated using dynamic optimization with a periodicity constraint. The NLP optimization is embedded in a multi-objective optimization framework to optimize the process with respect to two objective functions and generate the corresponding Pareto fronts. The first objective is the methanol outlet flow rate. The second objective is the methanol yield based on the total carbon in the feed. Additional constraints arising from the complex methanol reaction and the practical limitations are introduced step by step. The results show that significant improvements for both objective functions are possible through periodic forcing of the two inputs considered here.",
publisher = "MDPI",
journal = "Processes",
title = "Optimization of Methanol Synthesis under Forced Periodic Operation",
volume = "9",
number = "5",
pages = "872",
doi = "10.3390/pr9050872"
}

Seidel, C., Nikolić, D., Felischak, M., Petkovska, M., Seidel-Morgenstern, A.,& Kienle, A.. (2021). Optimization of Methanol Synthesis under Forced Periodic Operation. in Processes
MDPI., 9(5), 872.
https://doi.org/10.3390/pr9050872

Seidel C, Nikolić D, Felischak M, Petkovska M, Seidel-Morgenstern A, Kienle A. Optimization of Methanol Synthesis under Forced Periodic Operation. in Processes. 2021;9(5):872.
doi:10.3390/pr9050872 .

Seidel, Carsten, Nikolić, Daliborka, Felischak, Matthias, Petkovska, Menka, Seidel-Morgenstern, Andreas, Kienle, Achim, "Optimization of Methanol Synthesis under Forced Periodic Operation" in Processes, 9, no. 5 (2021):872,
https://doi.org/10.3390/pr9050872 . .

TY  - CONF
AU  - Seidel, Carsten
AU  - Felischak, Matthias
AU  - Nikolić, Daliborka
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
AU  - Kienle, Achim
PY  - 2020
UR  - https://www.mpi-magdeburg.mpg.de/Indo-German-Workshop2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3844
AB  - Methanol is an essential primary chemical in the chemical industry. Further, there is a
growing interest in using methanol also for chemical energy storage. Excess electrical
wind or solar energy can be converted to hydrogen and react with CO and CO2 from biogas
or waste streams to methanol. Suitable kinetic models are required for designing such
processes. Established kinetics need to be extended to account for strongly varying input
ratios of H2, CO, and CO2 in such applications leading to the need for dynamic process
operation. Kinetic models for methanol synthesis accounting for dynamic changes of the
catalyst morphology were proposed recently [1].
For the implementation and evaluation of the dynamic operation, a novel reactor concept,
incorporating a micro-berty reactor, is established. The configuration allows the
modulation of single and multiple input parameters simultaneously, such as partial
pressure, total flow-rate, and total pressure. Periodic variation of the inputs results in
fluctuating outputs. For the analysis of these changes, an online mass spectrometer (MS)
and a micro-gas chromatograph (GC) are implemented for time-resolved concentration
profiles, as well as the analysis of collected samples of multiple fluctuation periods.
A set of dynamic experiments is determined by optimal experimental design that
improves the parameter sensitivity by solving optimal control problems to identify an
optimal parameter set. Additionally, it is analyzed what kind of additional measurement
is required for further improvement of the identifiability of the kinetic model [2].
The nonlinear dynamic behavior of the methanol synthesis can be exploited by a forced
periodic modulation of different feed streams and total flow-rate (separately of
simultaneously) that result in improvements of the time-average output, in comparison to
the steady-state process, concerning different objective functions. The nonlinear
frequency response (NFR) analysis [3] is used to estimate suitable input variations and
the corresponding optimal dynamic parameters (forcing frequency, amplitudes, and phase
difference). The NFR method was already applied in various cases [4–6], and it represents
promising starting points for rigorous dynamic optimization.
The selection of the objective functions for single- and multi-objective optimization of
forced periodic operations is critically discussed.
C3  - 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany
T1  - Optimization of methanol synthesis under forced dynamic operation
UR  - https://hdl.handle.net/21.15107/rcub_cer_3844
ER  - 

@conference{
author = "Seidel, Carsten and Felischak, Matthias and Nikolić, Daliborka and Seidel-Morgenstern, Andreas and Petkovska, Menka and Kienle, Achim",
year = "2020",
abstract = "Methanol is an essential primary chemical in the chemical industry. Further, there is a
growing interest in using methanol also for chemical energy storage. Excess electrical
wind or solar energy can be converted to hydrogen and react with CO and CO2 from biogas
or waste streams to methanol. Suitable kinetic models are required for designing such
processes. Established kinetics need to be extended to account for strongly varying input
ratios of H2, CO, and CO2 in such applications leading to the need for dynamic process
operation. Kinetic models for methanol synthesis accounting for dynamic changes of the
catalyst morphology were proposed recently [1].
For the implementation and evaluation of the dynamic operation, a novel reactor concept,
incorporating a micro-berty reactor, is established. The configuration allows the
modulation of single and multiple input parameters simultaneously, such as partial
pressure, total flow-rate, and total pressure. Periodic variation of the inputs results in
fluctuating outputs. For the analysis of these changes, an online mass spectrometer (MS)
and a micro-gas chromatograph (GC) are implemented for time-resolved concentration
profiles, as well as the analysis of collected samples of multiple fluctuation periods.
A set of dynamic experiments is determined by optimal experimental design that
improves the parameter sensitivity by solving optimal control problems to identify an
optimal parameter set. Additionally, it is analyzed what kind of additional measurement
is required for further improvement of the identifiability of the kinetic model [2].
The nonlinear dynamic behavior of the methanol synthesis can be exploited by a forced
periodic modulation of different feed streams and total flow-rate (separately of
simultaneously) that result in improvements of the time-average output, in comparison to
the steady-state process, concerning different objective functions. The nonlinear
frequency response (NFR) analysis [3] is used to estimate suitable input variations and
the corresponding optimal dynamic parameters (forcing frequency, amplitudes, and phase
difference). The NFR method was already applied in various cases [4–6], and it represents
promising starting points for rigorous dynamic optimization.
The selection of the objective functions for single- and multi-objective optimization of
forced periodic operations is critically discussed.",
journal = "4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany",
title = "Optimization of methanol synthesis under forced dynamic operation",
url = "https://hdl.handle.net/21.15107/rcub_cer_3844"
}

Seidel, C., Felischak, M., Nikolić, D., Seidel-Morgenstern, A., Petkovska, M.,& Kienle, A.. (2020). Optimization of methanol synthesis under forced dynamic operation. in 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany.
https://hdl.handle.net/21.15107/rcub_cer_3844

Seidel C, Felischak M, Nikolić D, Seidel-Morgenstern A, Petkovska M, Kienle A. Optimization of methanol synthesis under forced dynamic operation. in 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany. 2020;.
https://hdl.handle.net/21.15107/rcub_cer_3844 .

Seidel, Carsten, Felischak, Matthias, Nikolić, Daliborka, Seidel-Morgenstern, Andreas, Petkovska, Menka, Kienle, Achim, "Optimization of methanol synthesis under forced dynamic operation" in 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany (2020),
https://hdl.handle.net/21.15107/rcub_cer_3844 .

TY  - CONF
AU  - Petkovska, Menka
AU  - Kienle, Achim
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Felischak, Matthias
AU  - Seidel-Morgenstern, Andreas
PY  - 2020
UR  - https://www.mpi-magdeburg.mpg.de/Indo-German-Workshop2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3846
AB  - We used the nonlinear frequency response (NFR) method in order to identify forced periodic conditions under which the acetic acid anhydride hydrolysis (chosen as a test reaction) can be favorably performed in a CSTR. Based on the results of the theoretical analysis, experimental investigations were performed using a lab-scale reactor exposed to two fluctuating inlet streams (water and acetic anhydride) with adjustable flow-rates, which enables modulation of the inlet reactant concentrations or/and total flow-rates in a flexible manner. The concentration of acetic acid formed is measured in the reactor online and used to monitor the process dynamics. Averaged values of the product outlet stream serve to validate the mean values predicted by NFR analysis and to evaluate the potential of this flexible forcing strategy. Recently we started to analyze both theoretically and experimentally the potential of applying a forced periodic operation to improve the methanol synthesis from CO, CO2 and H2 using the conventional Cu/ZnO/Al2O3 catalysts. This work is based on a recently published detailed model of this reaction, which is capable to quantify the rates under dynamic conditions (C. Seidel, A. Jörke, B. Vollbrecht, A. Seidel-Morgenstern, A. Kienle, Chem. Eng. Sci. 175 (2917) 130–138).
C3  - 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany
T1  - Forced periodic reactor operation
UR  - https://hdl.handle.net/21.15107/rcub_cer_3846
ER  - 

@conference{
author = "Petkovska, Menka and Kienle, Achim and Nikolić, Daliborka and Seidel, Carsten and Felischak, Matthias and Seidel-Morgenstern, Andreas",
year = "2020",
abstract = "We used the nonlinear frequency response (NFR) method in order to identify forced periodic conditions under which the acetic acid anhydride hydrolysis (chosen as a test reaction) can be favorably performed in a CSTR. Based on the results of the theoretical analysis, experimental investigations were performed using a lab-scale reactor exposed to two fluctuating inlet streams (water and acetic anhydride) with adjustable flow-rates, which enables modulation of the inlet reactant concentrations or/and total flow-rates in a flexible manner. The concentration of acetic acid formed is measured in the reactor online and used to monitor the process dynamics. Averaged values of the product outlet stream serve to validate the mean values predicted by NFR analysis and to evaluate the potential of this flexible forcing strategy. Recently we started to analyze both theoretically and experimentally the potential of applying a forced periodic operation to improve the methanol synthesis from CO, CO2 and H2 using the conventional Cu/ZnO/Al2O3 catalysts. This work is based on a recently published detailed model of this reaction, which is capable to quantify the rates under dynamic conditions (C. Seidel, A. Jörke, B. Vollbrecht, A. Seidel-Morgenstern, A. Kienle, Chem. Eng. Sci. 175 (2917) 130–138).",
journal = "4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany",
title = "Forced periodic reactor operation",
url = "https://hdl.handle.net/21.15107/rcub_cer_3846"
}

Petkovska, M., Kienle, A., Nikolić, D., Seidel, C., Felischak, M.,& Seidel-Morgenstern, A.. (2020). Forced periodic reactor operation. in 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany.
https://hdl.handle.net/21.15107/rcub_cer_3846

Petkovska M, Kienle A, Nikolić D, Seidel C, Felischak M, Seidel-Morgenstern A. Forced periodic reactor operation. in 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany. 2020;.
https://hdl.handle.net/21.15107/rcub_cer_3846 .

Petkovska, Menka, Kienle, Achim, Nikolić, Daliborka, Seidel, Carsten, Felischak, Matthias, Seidel-Morgenstern, Andreas, "Forced periodic reactor operation" in 4th Indo-German Workshop on Advances in Materials, Reaction& Separation Processes, Berlin, Germany (2020),
https://hdl.handle.net/21.15107/rcub_cer_3846 .

TY  - CONF
AU  - Kaps, Lothar
AU  - Felischak, Matthias
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Hamel, Christof
AU  - Seidel-Morgenstern, Andreas
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4042
AB  - Continuous chemical reactors are mostly operated under steady-state conditions. However, theoretical studies reveal that forced periodic operation (FPO) can lead to better performance. To predict and optimize FPO, the nonlinear frequency response (NFR) method provides an analytical approach. The presented work is focused on providing theoretical and experimental results devoted to demonstrating both the potential of forced periodic operation and the strength of the NFR method to identify suitable operating conditions. The hydrolysis of acetic anhydride is studied experimentally as a model reaction applying an adiabatic continuous stirred tank reactor (CSTR).
PB  - WILEY-VCH
C3  - Chemie Ingenieur Technik
T1  - Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method
VL  - 92
IS  - 9
SP  - 1346
EP  - 1346
DO  - 10.1002/cite.202055082
ER  - 

@conference{
author = "Kaps, Lothar and Felischak, Matthias and Nikolić, Daliborka and Petkovska, Menka and Hamel, Christof and Seidel-Morgenstern, Andreas",
year = "2020",
abstract = "Continuous chemical reactors are mostly operated under steady-state conditions. However, theoretical studies reveal that forced periodic operation (FPO) can lead to better performance. To predict and optimize FPO, the nonlinear frequency response (NFR) method provides an analytical approach. The presented work is focused on providing theoretical and experimental results devoted to demonstrating both the potential of forced periodic operation and the strength of the NFR method to identify suitable operating conditions. The hydrolysis of acetic anhydride is studied experimentally as a model reaction applying an adiabatic continuous stirred tank reactor (CSTR).",
publisher = "WILEY-VCH",
journal = "Chemie Ingenieur Technik",
title = "Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method",
volume = "92",
number = "9",
pages = "1346-1346",
doi = "10.1002/cite.202055082"
}

Kaps, L., Felischak, M., Nikolić, D., Petkovska, M., Hamel, C.,& Seidel-Morgenstern, A.. (2020). Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method. in Chemie Ingenieur Technik
WILEY-VCH., 92(9), 1346-1346.
https://doi.org/10.1002/cite.202055082

Kaps L, Felischak M, Nikolić D, Petkovska M, Hamel C, Seidel-Morgenstern A. Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method. in Chemie Ingenieur Technik. 2020;92(9):1346-1346.
doi:10.1002/cite.202055082 .

Kaps, Lothar, Felischak, Matthias, Nikolić, Daliborka, Petkovska, Menka, Hamel, Christof, Seidel-Morgenstern, Andreas, "Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method" in Chemie Ingenieur Technik, 92, no. 9 (2020):1346-1346,
https://doi.org/10.1002/cite.202055082 . .

TY  - CONF
AU  - Kaps, Lothar
AU  - Felischak, Matthias
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Hamel, Christof
AU  - Seidel-Morgenstern, Andreas
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4043
AB  - Continuous chemical reactors are mostly operated under steady-state conditions. However, theoretical studies reveal that forced periodic operation (FPO) can lead to better performance. To predict and optimize FPO, the nonlinear frequency response (NFR) method provides an analytical approach. The presented work is focused on providing theoretical and experimental results devoted to demonstrating both the potential of forced periodic operation and the strength of the NFR method to identify suitable operating conditions. The hydrolysis of acetic anhydride is studied experimentally as a model reaction applying an adiabatic continuous stirred tank reactor (CSTR).
PB  - Wiley
C3  - Chemie Ingenieur Technik
T1  - Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method
VL  - 92
IS  - 9
SP  - 1346
EP  - 1346
DO  - 10.1002/cite.202055082
ER  - 

@conference{
author = "Kaps, Lothar and Felischak, Matthias and Nikolić, Daliborka and Petkovska, Menka and Hamel, Christof and Seidel-Morgenstern, Andreas",
year = "2020",
abstract = "Continuous chemical reactors are mostly operated under steady-state conditions. However, theoretical studies reveal that forced periodic operation (FPO) can lead to better performance. To predict and optimize FPO, the nonlinear frequency response (NFR) method provides an analytical approach. The presented work is focused on providing theoretical and experimental results devoted to demonstrating both the potential of forced periodic operation and the strength of the NFR method to identify suitable operating conditions. The hydrolysis of acetic anhydride is studied experimentally as a model reaction applying an adiabatic continuous stirred tank reactor (CSTR).",
publisher = "Wiley",
journal = "Chemie Ingenieur Technik",
title = "Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method",
volume = "92",
number = "9",
pages = "1346-1346",
doi = "10.1002/cite.202055082"
}

Kaps, L., Felischak, M., Nikolić, D., Petkovska, M., Hamel, C.,& Seidel-Morgenstern, A.. (2020). Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method. in Chemie Ingenieur Technik
Wiley., 92(9), 1346-1346.
https://doi.org/10.1002/cite.202055082

Kaps L, Felischak M, Nikolić D, Petkovska M, Hamel C, Seidel-Morgenstern A. Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method. in Chemie Ingenieur Technik. 2020;92(9):1346-1346.
doi:10.1002/cite.202055082 .

Kaps, Lothar, Felischak, Matthias, Nikolić, Daliborka, Petkovska, Menka, Hamel, Christof, Seidel-Morgenstern, Andreas, "Forced periodic reactor operation: Analysis of process and forcing parameters exploiting the nonlinear frequency response method" in Chemie Ingenieur Technik, 92, no. 9 (2020):1346-1346,
https://doi.org/10.1002/cite.202055082 . .

TY  - JOUR
AU  - Nikolić-Paunić, Daliborka
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3599
AB  - Nonlinear frequency response (NFR) method was used to evaluate the forced periodic operations and
their potential for improving the system performance compared to steady-state operations. The NFR
method was used to evaluate the time-average performances of forced periodically operated systems
subjected to simultaneous periodic modulation of two-inputs of general waveforms. As an example, a
forced periodically operated adiabatic CSTR with simple nth order reaction A ? mPP and square-wave
modulation of two pairs of inputs were analyzed in detail. The theory is illustrated analyzing the hydrolysis
of acetic acid anhydride performed in a laboratory scale adiabatic CSTR. The results showed that significant
improvements could be achieved by simultaneous modulation of both pairs of inputs.
Comparison with the results of numerical integration showed that the approximation using only the
asymmetrical second order FRFs and the first three harmonics of the inputs provide very reliable predictions
of the DC component.
PB  - Elsevier
T2  - Chemical Engineering Science
T1  - Nonlinear frequency response analysis of forced periodic operations with simultaneous modulation of two general waveform inputs with applications on adiabatic CSTR with square-wave modulations
VL  - 226
SP  - 115842
DO  - 10.1016/j.ces.2020.115842
ER  - 

@article{
author = "Nikolić-Paunić, Daliborka and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2020",
abstract = "Nonlinear frequency response (NFR) method was used to evaluate the forced periodic operations and
their potential for improving the system performance compared to steady-state operations. The NFR
method was used to evaluate the time-average performances of forced periodically operated systems
subjected to simultaneous periodic modulation of two-inputs of general waveforms. As an example, a
forced periodically operated adiabatic CSTR with simple nth order reaction A ? mPP and square-wave
modulation of two pairs of inputs were analyzed in detail. The theory is illustrated analyzing the hydrolysis
of acetic acid anhydride performed in a laboratory scale adiabatic CSTR. The results showed that significant
improvements could be achieved by simultaneous modulation of both pairs of inputs.
Comparison with the results of numerical integration showed that the approximation using only the
asymmetrical second order FRFs and the first three harmonics of the inputs provide very reliable predictions
of the DC component.",
publisher = "Elsevier",
journal = "Chemical Engineering Science",
title = "Nonlinear frequency response analysis of forced periodic operations with simultaneous modulation of two general waveform inputs with applications on adiabatic CSTR with square-wave modulations",
volume = "226",
pages = "115842",
doi = "10.1016/j.ces.2020.115842"
}

Nikolić-Paunić, D., Seidel-Morgenstern, A.,& Petkovska, M.. (2020). Nonlinear frequency response analysis of forced periodic operations with simultaneous modulation of two general waveform inputs with applications on adiabatic CSTR with square-wave modulations. in Chemical Engineering Science
Elsevier., 226, 115842.
https://doi.org/10.1016/j.ces.2020.115842

Nikolić-Paunić D, Seidel-Morgenstern A, Petkovska M. Nonlinear frequency response analysis of forced periodic operations with simultaneous modulation of two general waveform inputs with applications on adiabatic CSTR with square-wave modulations. in Chemical Engineering Science. 2020;226:115842.
doi:10.1016/j.ces.2020.115842 .

Nikolić-Paunić, Daliborka, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Nonlinear frequency response analysis of forced periodic operations with simultaneous modulation of two general waveform inputs with applications on adiabatic CSTR with square-wave modulations" in Chemical Engineering Science, 226 (2020):115842,
https://doi.org/10.1016/j.ces.2020.115842 . .

TY  - CONF
AU  - Felischak, Matthias
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Hamel, Christof
AU  - Seidel-Morgenstern, Andreas
PY  - 2019
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3842
AB  - The classical design of continuous chemical reactors exploits steady-state operation, which is optimized and maintained by appropriate control systems. Nevertheless, it is well-known that the reactor performance can be enhanced by applying periodic regimes, like forced modulations of input parameters.The identification and evaluation of suitable periodic operation conditions is
challenging. One approach that can be used is based on nonlinear frequency response (NFR) analysis. The focus of this work is the experimental analysis of shapes for two simultaneously imposed modulations (sinusoidal and square) in comparison to results predicted by the NFR method. The acetic anhydride hydrolysis was studied in an adiabatic CSTR exploiting a periodic operation mode, which was found to be superior to the corresponding steady-state operation.
C3  - German reaction Engineering Meeting (DECHEMA), Wuerzburg, Germany
T1  - Forced Periodic Operation: Effect of shapes for two simultaneously imposed modulations
UR  - https://hdl.handle.net/21.15107/rcub_cer_3842
ER  - 

@conference{
author = "Felischak, Matthias and Nikolić, Daliborka and Petkovska, Menka and Hamel, Christof and Seidel-Morgenstern, Andreas",
year = "2019",
abstract = "The classical design of continuous chemical reactors exploits steady-state operation, which is optimized and maintained by appropriate control systems. Nevertheless, it is well-known that the reactor performance can be enhanced by applying periodic regimes, like forced modulations of input parameters.The identification and evaluation of suitable periodic operation conditions is
challenging. One approach that can be used is based on nonlinear frequency response (NFR) analysis. The focus of this work is the experimental analysis of shapes for two simultaneously imposed modulations (sinusoidal and square) in comparison to results predicted by the NFR method. The acetic anhydride hydrolysis was studied in an adiabatic CSTR exploiting a periodic operation mode, which was found to be superior to the corresponding steady-state operation.",
journal = "German reaction Engineering Meeting (DECHEMA), Wuerzburg, Germany",
title = "Forced Periodic Operation: Effect of shapes for two simultaneously imposed modulations",
url = "https://hdl.handle.net/21.15107/rcub_cer_3842"
}

Felischak, M., Nikolić, D., Petkovska, M., Hamel, C.,& Seidel-Morgenstern, A.. (2019). Forced Periodic Operation: Effect of shapes for two simultaneously imposed modulations. in German reaction Engineering Meeting (DECHEMA), Wuerzburg, Germany.
https://hdl.handle.net/21.15107/rcub_cer_3842

Felischak M, Nikolić D, Petkovska M, Hamel C, Seidel-Morgenstern A. Forced Periodic Operation: Effect of shapes for two simultaneously imposed modulations. in German reaction Engineering Meeting (DECHEMA), Wuerzburg, Germany. 2019;.
https://hdl.handle.net/21.15107/rcub_cer_3842 .

Felischak, Matthias, Nikolić, Daliborka, Petkovska, Menka, Hamel, Christof, Seidel-Morgenstern, Andreas, "Forced Periodic Operation: Effect of shapes for two simultaneously imposed modulations" in German reaction Engineering Meeting (DECHEMA), Wuerzburg, Germany (2019),
https://hdl.handle.net/21.15107/rcub_cer_3842 .

TY  - CONF
AU  - Nikolić, Daliborka
AU  - Seidel, Carsten
AU  - Kienle, Achim
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2019
UR  - https://kuleuvencongres.be/ipic2019/Home
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3843
AB  - In this work, the NFR method is implemented for evaluation of possible improvement for the reaction of methanol synthesis by hydrogenation of CO and CO2, using a standard Cu/ZnO/Al2O3 catalyst. For start, a forced periodically operated isothermal continuous-stirred tank reactor (CSTR) is considered. A simplified (lumped) kinetic model of methanol synthesis with 14 parameters which were estimated from the results of an extensive experimental investigation is used. The NFR method is performed for evaluation of possible increase of methanol production by modulating the mole fractions of CO and CO2 in the feed stream, as well as their simultaneous modulation. The necessary asymmetrical second order frequency response functions correlating the methanol production with the modulated inputs are derived and the forcing
parameters leading to improvement of the reactor performance are determined. The results of
the NFR analysis will further be used for rigorous optimisation of the forced periodic operations
and planning the best experimental scenarios. The final step will be experimental investigation and confirmation on a laboratory scale reactor.
C3  - 2nd International Process Intensification Conference, Leuven, Belgium
T1  - Intensification of a chemical reactor for methanol synthesis through forced periodic operations- Evaluation based on Nonlinear Frequency Response Analysis
UR  - https://hdl.handle.net/21.15107/rcub_cer_3843
ER  - 

@conference{
author = "Nikolić, Daliborka and Seidel, Carsten and Kienle, Achim and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2019",
abstract = "In this work, the NFR method is implemented for evaluation of possible improvement for the reaction of methanol synthesis by hydrogenation of CO and CO2, using a standard Cu/ZnO/Al2O3 catalyst. For start, a forced periodically operated isothermal continuous-stirred tank reactor (CSTR) is considered. A simplified (lumped) kinetic model of methanol synthesis with 14 parameters which were estimated from the results of an extensive experimental investigation is used. The NFR method is performed for evaluation of possible increase of methanol production by modulating the mole fractions of CO and CO2 in the feed stream, as well as their simultaneous modulation. The necessary asymmetrical second order frequency response functions correlating the methanol production with the modulated inputs are derived and the forcing
parameters leading to improvement of the reactor performance are determined. The results of
the NFR analysis will further be used for rigorous optimisation of the forced periodic operations
and planning the best experimental scenarios. The final step will be experimental investigation and confirmation on a laboratory scale reactor.",
journal = "2nd International Process Intensification Conference, Leuven, Belgium",
title = "Intensification of a chemical reactor for methanol synthesis through forced periodic operations- Evaluation based on Nonlinear Frequency Response Analysis",
url = "https://hdl.handle.net/21.15107/rcub_cer_3843"
}

Nikolić, D., Seidel, C., Kienle, A., Seidel-Morgenstern, A.,& Petkovska, M.. (2019). Intensification of a chemical reactor for methanol synthesis through forced periodic operations- Evaluation based on Nonlinear Frequency Response Analysis. in 2nd International Process Intensification Conference, Leuven, Belgium.
https://hdl.handle.net/21.15107/rcub_cer_3843

Nikolić D, Seidel C, Kienle A, Seidel-Morgenstern A, Petkovska M. Intensification of a chemical reactor for methanol synthesis through forced periodic operations- Evaluation based on Nonlinear Frequency Response Analysis. in 2nd International Process Intensification Conference, Leuven, Belgium. 2019;.
https://hdl.handle.net/21.15107/rcub_cer_3843 .

Nikolić, Daliborka, Seidel, Carsten, Kienle, Achim, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Intensification of a chemical reactor for methanol synthesis through forced periodic operations- Evaluation based on Nonlinear Frequency Response Analysis" in 2nd International Process Intensification Conference, Leuven, Belgium (2019),
https://hdl.handle.net/21.15107/rcub_cer_3843 .

TY  - CONF
AU  - Felischak, Matthias
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Seidel-Morgenstern, Andreas
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3816
AB  - The classical design of continuously operated chemical reactors assumes that they are operated in a steady-state which is usually optimized and maintained by using appropriate control systems. Nevertheless, it has been known for quite some time that, in some cases, better performance can be achieved by applying a periodic regime exploiting forced modulations of one or more inputs to the reactor [1,2]. Finding out whether, at which conditions and to which extent periodic operation can be superior to the optimal steady-state is difficult. One approach that can be used is an approximate, analytical method called nonlinear frequency response (NFR) method [3].

The NFR method is based on the concept of higher order frequency response functions (FRFs) and applicable for weakly nonlinear systems [3]. Frequency response of a weakly nonlinear system, in addition to the basic harmonic, contains a non-periodic (DC) term and, theoretically, an infinite sequence of higher harmonics. The DC component of the output is responsible for the average performance of the periodically operated reactor, and its sign and value define whether, and to which extent, the periodic operation leads to process improvement. Using the NFR method, this DC component can be approximately estimated from a single asymmetrical second order FRF (for modulation of a single input) or from several single input and cross- asymmetrical second order FRFs (for multiple-input modulation). For the case of multiple modulated inputs, the optimal phase difference between the modulated inputs, which is an essential parameter, can be directly determined [4,5]. Promising parameters to be periodically modulated separately or simultaneously are clearly the reactant inlet concentrations, the flow-rates and the feed temperatures. 

We used the NFR method in order to identify forced periodic conditions under which the acetic acid anhydride hydrolysis (chosen as a test reaction) can be favorably performed in a CSTR. Based on the results of the theoretical analysis, experimental investigations were performed using a lab-scale reactor exposed to two fluctuating inlet streams (water and acetic anhydride) with adjustable flow-rates, which enables modulation of the inlet reactant concentrations or/and total flow-rates in a flexible manner. The concentration of the acetic acid formed is measured in the reactor online and used to monitor the process dynamics. Averaged values of the product outlet stream serve to validate the mean values predicted by NFR analysis and to evaluate the potential of this flexible forcing strategy.
C3  - American Institute of Chemical Engineers Annual Meeting (AIChE Annual Meeting), Pittsburgh, USA
T1  - Forced periodic reactor operation with simultaneous modulation of two inputs: Nonlinear frequency response analysis  and experimental demonstration
UR  - https://hdl.handle.net/21.15107/rcub_cer_3816
ER  - 

@conference{
author = "Felischak, Matthias and Nikolić, Daliborka and Petkovska, Menka and Seidel-Morgenstern, Andreas",
year = "2018",
abstract = "The classical design of continuously operated chemical reactors assumes that they are operated in a steady-state which is usually optimized and maintained by using appropriate control systems. Nevertheless, it has been known for quite some time that, in some cases, better performance can be achieved by applying a periodic regime exploiting forced modulations of one or more inputs to the reactor [1,2]. Finding out whether, at which conditions and to which extent periodic operation can be superior to the optimal steady-state is difficult. One approach that can be used is an approximate, analytical method called nonlinear frequency response (NFR) method [3].

The NFR method is based on the concept of higher order frequency response functions (FRFs) and applicable for weakly nonlinear systems [3]. Frequency response of a weakly nonlinear system, in addition to the basic harmonic, contains a non-periodic (DC) term and, theoretically, an infinite sequence of higher harmonics. The DC component of the output is responsible for the average performance of the periodically operated reactor, and its sign and value define whether, and to which extent, the periodic operation leads to process improvement. Using the NFR method, this DC component can be approximately estimated from a single asymmetrical second order FRF (for modulation of a single input) or from several single input and cross- asymmetrical second order FRFs (for multiple-input modulation). For the case of multiple modulated inputs, the optimal phase difference between the modulated inputs, which is an essential parameter, can be directly determined [4,5]. Promising parameters to be periodically modulated separately or simultaneously are clearly the reactant inlet concentrations, the flow-rates and the feed temperatures. 

We used the NFR method in order to identify forced periodic conditions under which the acetic acid anhydride hydrolysis (chosen as a test reaction) can be favorably performed in a CSTR. Based on the results of the theoretical analysis, experimental investigations were performed using a lab-scale reactor exposed to two fluctuating inlet streams (water and acetic anhydride) with adjustable flow-rates, which enables modulation of the inlet reactant concentrations or/and total flow-rates in a flexible manner. The concentration of the acetic acid formed is measured in the reactor online and used to monitor the process dynamics. Averaged values of the product outlet stream serve to validate the mean values predicted by NFR analysis and to evaluate the potential of this flexible forcing strategy.",
journal = "American Institute of Chemical Engineers Annual Meeting (AIChE Annual Meeting), Pittsburgh, USA",
title = "Forced periodic reactor operation with simultaneous modulation of two inputs: Nonlinear frequency response analysis  and experimental demonstration",
url = "https://hdl.handle.net/21.15107/rcub_cer_3816"
}

Felischak, M., Nikolić, D., Petkovska, M.,& Seidel-Morgenstern, A.. (2018). Forced periodic reactor operation with simultaneous modulation of two inputs: Nonlinear frequency response analysis  and experimental demonstration. in American Institute of Chemical Engineers Annual Meeting (AIChE Annual Meeting), Pittsburgh, USA.
https://hdl.handle.net/21.15107/rcub_cer_3816

Felischak M, Nikolić D, Petkovska M, Seidel-Morgenstern A. Forced periodic reactor operation with simultaneous modulation of two inputs: Nonlinear frequency response analysis  and experimental demonstration. in American Institute of Chemical Engineers Annual Meeting (AIChE Annual Meeting), Pittsburgh, USA. 2018;.
https://hdl.handle.net/21.15107/rcub_cer_3816 .

Felischak, Matthias, Nikolić, Daliborka, Petkovska, Menka, Seidel-Morgenstern, Andreas, "Forced periodic reactor operation with simultaneous modulation of two inputs: Nonlinear frequency response analysis  and experimental demonstration" in American Institute of Chemical Engineers Annual Meeting (AIChE Annual Meeting), Pittsburgh, USA (2018),
https://hdl.handle.net/21.15107/rcub_cer_3816 .

TY  - CONF
AU  - Currie, Robert
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Simakov, David
PY  - 2018
UR  - https://www.aidic.it/iscre25/programme.php
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3836
AB  - Nonlinear frequency response (NFR) analysis was applied on a Sabatier reactor. A substantial improvement in CO2 conversion was predicted under certain conditions. The NFR analysis prediction was validated using a kinetic flow reactor model. A comprehensive packed bed model was analyzed using NFR as a guidance.
C3  - The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy
T1  - CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study
SP  - P52
UR  - https://hdl.handle.net/21.15107/rcub_cer_3836
ER  - 

@conference{
author = "Currie, Robert and Nikolić, Daliborka and Petkovska, Menka and Simakov, David",
year = "2018",
abstract = "Nonlinear frequency response (NFR) analysis was applied on a Sabatier reactor. A substantial improvement in CO2 conversion was predicted under certain conditions. The NFR analysis prediction was validated using a kinetic flow reactor model. A comprehensive packed bed model was analyzed using NFR as a guidance.",
journal = "The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy",
title = "CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study",
pages = "P52",
url = "https://hdl.handle.net/21.15107/rcub_cer_3836"
}

Currie, R., Nikolić, D., Petkovska, M.,& Simakov, D.. (2018). CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study. in The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy, P52.
https://hdl.handle.net/21.15107/rcub_cer_3836

Currie R, Nikolić D, Petkovska M, Simakov D. CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study. in The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy. 2018;:P52.
https://hdl.handle.net/21.15107/rcub_cer_3836 .

Currie, Robert, Nikolić, Daliborka, Petkovska, Menka, Simakov, David, "CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study" in The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy (2018):P52,
https://hdl.handle.net/21.15107/rcub_cer_3836 .

TY  - CONF
AU  - Felischak, Matthias
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Seidel-Morgenstern, Andreas
PY  - 2018
UR  - https://www.aidic.it/iscre25/programme.php
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3839
AB  - Theoretical evaluation of possible reactor improvement for periodic operation. Automated experimental setup was built, with a lab-scale CSTR and adjustable flow-rates, in which periodic operations can be conducted. The concept was implemented for the hydrolysis of acetic anhydride as a model reaction.
C3  - The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy
T1  - Forced periodic reactor operation with simultaneous modulation of two inputs: Experimental investigation based on Nonlinear Frequency Response Analysis
UR  - https://hdl.handle.net/21.15107/rcub_cer_3839
ER  - 

@conference{
author = "Felischak, Matthias and Nikolić, Daliborka and Petkovska, Menka and Seidel-Morgenstern, Andreas",
year = "2018",
abstract = "Theoretical evaluation of possible reactor improvement for periodic operation. Automated experimental setup was built, with a lab-scale CSTR and adjustable flow-rates, in which periodic operations can be conducted. The concept was implemented for the hydrolysis of acetic anhydride as a model reaction.",
journal = "The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy",
title = "Forced periodic reactor operation with simultaneous modulation of two inputs: Experimental investigation based on Nonlinear Frequency Response Analysis",
url = "https://hdl.handle.net/21.15107/rcub_cer_3839"
}

Felischak, M., Nikolić, D., Petkovska, M.,& Seidel-Morgenstern, A.. (2018). Forced periodic reactor operation with simultaneous modulation of two inputs: Experimental investigation based on Nonlinear Frequency Response Analysis. in The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy.
https://hdl.handle.net/21.15107/rcub_cer_3839

Felischak M, Nikolić D, Petkovska M, Seidel-Morgenstern A. Forced periodic reactor operation with simultaneous modulation of two inputs: Experimental investigation based on Nonlinear Frequency Response Analysis. in The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy. 2018;.
https://hdl.handle.net/21.15107/rcub_cer_3839 .

Felischak, Matthias, Nikolić, Daliborka, Petkovska, Menka, Seidel-Morgenstern, Andreas, "Forced periodic reactor operation with simultaneous modulation of two inputs: Experimental investigation based on Nonlinear Frequency Response Analysis" in The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy (2018),
https://hdl.handle.net/21.15107/rcub_cer_3839 .

TY  - CONF
AU  - Currie, Robert
AU  - Nikolić, Daliborka
AU  - Petkovska, Menka
AU  - Simakov, David
PY  - 2018
UR  - https://www.aidic.it/iscre25/programme.php
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3837
AB  - Poster presented at: The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy, 20-23 May 2018
T1  - CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study
UR  - https://hdl.handle.net/21.15107/rcub_cer_3837
ER  - 

@conference{
author = "Currie, Robert and Nikolić, Daliborka and Petkovska, Menka and Simakov, David",
year = "2018",
abstract = "Poster presented at: The 25th International Symposium of Chemical Reaction Engineering (ISCRE 25), Florance, Italy, 20-23 May 2018",
title = "CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study",
url = "https://hdl.handle.net/21.15107/rcub_cer_3837"
}

Currie, R., Nikolić, D., Petkovska, M.,& Simakov, D.. (2018). CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study. .
https://hdl.handle.net/21.15107/rcub_cer_3837

Currie R, Nikolić D, Petkovska M, Simakov D. CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study. 2018;.
https://hdl.handle.net/21.15107/rcub_cer_3837 .

Currie, Robert, Nikolić, Daliborka, Petkovska, Menka, Simakov, David, "CO2 conversion enhancement in a periodically operated Sabatier reactor: Nonlinear frequency response analysis and simulation- based Study" (2018),
https://hdl.handle.net/21.15107/rcub_cer_3837 .

TY  - JOUR
AU  - Currie, Robert
AU  - Nikolić-Paunić, Daliborka
AU  - Petkovska, Menka
AU  - Simakov, David S. A.
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2446
AB  - Conversion of CO2 into synthetic CH4 via thermocatalytic hydrogenation (the Sabatier reaction), has recently gained increasing interest as a possible route for CO2 utilization and energy storage pathway. Herein, we analyze the possibility of increasing the CO2 conversion through periodic operation of the reactor. The analysis is performed by using the Nonlinear Frequency Response (NFR) method, a recently developed analytical technique, suitable for fast evaluation of periodic reactor operations. The NFR analysis predicts a significant conversion gain (up to 50%) for certain frequencies of the feed flow rate modulation. This prediction is validated by numerical simulations with a reaction rate expression obtained by CO2 conversion experiments using a Ni/Al2O3 catalysts. Both the NFR analysis and numerical simulations predict that it is possible to obtain 70% CO2 conversion at 500 K, 5 bar, and average space velocity of 7600 h(-1) by a periodic modulation of the feed flow rate, as compared to the corresponding steady state CO2 conversion of 43%.
PB  - Wiley
T2  - Israel Journal of Chemistry
T1  - CO2 Conversion Enhancement in a Periodically Operated Sabatier Reactor: Nonlinear Frequency Response Analysis and Simulation-based Study
VL  - 58
IS  - 6-7
SP  - 762
EP  - 775
DO  - 10.1002/ijch.201700134
ER  - 

@article{
author = "Currie, Robert and Nikolić-Paunić, Daliborka and Petkovska, Menka and Simakov, David S. A.",
year = "2018",
abstract = "Conversion of CO2 into synthetic CH4 via thermocatalytic hydrogenation (the Sabatier reaction), has recently gained increasing interest as a possible route for CO2 utilization and energy storage pathway. Herein, we analyze the possibility of increasing the CO2 conversion through periodic operation of the reactor. The analysis is performed by using the Nonlinear Frequency Response (NFR) method, a recently developed analytical technique, suitable for fast evaluation of periodic reactor operations. The NFR analysis predicts a significant conversion gain (up to 50%) for certain frequencies of the feed flow rate modulation. This prediction is validated by numerical simulations with a reaction rate expression obtained by CO2 conversion experiments using a Ni/Al2O3 catalysts. Both the NFR analysis and numerical simulations predict that it is possible to obtain 70% CO2 conversion at 500 K, 5 bar, and average space velocity of 7600 h(-1) by a periodic modulation of the feed flow rate, as compared to the corresponding steady state CO2 conversion of 43%.",
publisher = "Wiley",
journal = "Israel Journal of Chemistry",
title = "CO2 Conversion Enhancement in a Periodically Operated Sabatier Reactor: Nonlinear Frequency Response Analysis and Simulation-based Study",
volume = "58",
number = "6-7",
pages = "762-775",
doi = "10.1002/ijch.201700134"
}

Currie, R., Nikolić-Paunić, D., Petkovska, M.,& Simakov, D. S. A.. (2018). CO2 Conversion Enhancement in a Periodically Operated Sabatier Reactor: Nonlinear Frequency Response Analysis and Simulation-based Study. in Israel Journal of Chemistry
Wiley., 58(6-7), 762-775.
https://doi.org/10.1002/ijch.201700134

Currie R, Nikolić-Paunić D, Petkovska M, Simakov DSA. CO2 Conversion Enhancement in a Periodically Operated Sabatier Reactor: Nonlinear Frequency Response Analysis and Simulation-based Study. in Israel Journal of Chemistry. 2018;58(6-7):762-775.
doi:10.1002/ijch.201700134 .

Currie, Robert, Nikolić-Paunić, Daliborka, Petkovska, Menka, Simakov, David S. A., "CO2 Conversion Enhancement in a Periodically Operated Sabatier Reactor: Nonlinear Frequency Response Analysis and Simulation-based Study" in Israel Journal of Chemistry, 58, no. 6-7 (2018):762-775,
https://doi.org/10.1002/ijch.201700134 . .

TY  - JOUR
AU  - Petkovska, Menka
AU  - Nikolić-Paunić, Daliborka
AU  - Seidel-Morgenstern, Andreas
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2427
AB  - Nonlinear Frequency Response (NFR) method is a relatively new method which can be used for fast evaluation of possible process improvements through periodic operations. The method is analytical and approximate. Its main task is to give an answer whether periodic modulation of one or more process inputs can result in improved process performance. The method is explained in brief and an overview of the existing applications is given. The review covers simple reactions performed in isothermal and non-isothermal stirred tank reactors exposed to different modulated inputs (inlet concentration, flow-rate, inlet temperature, temperature of the heating/cooling medium). Processes with two simultaneously modulated inputs and different shapes of the periodic input are also considered. The results of the NFR method are compared with the results of numerical simulation and a critical evaluation of the method is given.
PB  - Wiley
T2  - Israel Journal of Chemistry
T1  - Nonlinear Frequency Response Method for Evaluating Forced Periodic Operations of Chemical Reactors
VL  - 58
IS  - 6-7
SP  - 663
EP  - 681
DO  - 10.1002/ijch.201700132
ER  - 

@article{
author = "Petkovska, Menka and Nikolić-Paunić, Daliborka and Seidel-Morgenstern, Andreas",
year = "2018",
abstract = "Nonlinear Frequency Response (NFR) method is a relatively new method which can be used for fast evaluation of possible process improvements through periodic operations. The method is analytical and approximate. Its main task is to give an answer whether periodic modulation of one or more process inputs can result in improved process performance. The method is explained in brief and an overview of the existing applications is given. The review covers simple reactions performed in isothermal and non-isothermal stirred tank reactors exposed to different modulated inputs (inlet concentration, flow-rate, inlet temperature, temperature of the heating/cooling medium). Processes with two simultaneously modulated inputs and different shapes of the periodic input are also considered. The results of the NFR method are compared with the results of numerical simulation and a critical evaluation of the method is given.",
publisher = "Wiley",
journal = "Israel Journal of Chemistry",
title = "Nonlinear Frequency Response Method for Evaluating Forced Periodic Operations of Chemical Reactors",
volume = "58",
number = "6-7",
pages = "663-681",
doi = "10.1002/ijch.201700132"
}

Petkovska, M., Nikolić-Paunić, D.,& Seidel-Morgenstern, A.. (2018). Nonlinear Frequency Response Method for Evaluating Forced Periodic Operations of Chemical Reactors. in Israel Journal of Chemistry
Wiley., 58(6-7), 663-681.
https://doi.org/10.1002/ijch.201700132

Petkovska M, Nikolić-Paunić D, Seidel-Morgenstern A. Nonlinear Frequency Response Method for Evaluating Forced Periodic Operations of Chemical Reactors. in Israel Journal of Chemistry. 2018;58(6-7):663-681.
doi:10.1002/ijch.201700132 .

Petkovska, Menka, Nikolić-Paunić, Daliborka, Seidel-Morgenstern, Andreas, "Nonlinear Frequency Response Method for Evaluating Forced Periodic Operations of Chemical Reactors" in Israel Journal of Chemistry, 58, no. 6-7 (2018):663-681,
https://doi.org/10.1002/ijch.201700132 . .

TY  - CONF
AU  - Nikolić, Daliborka
AU  - Felischak, Matthias
AU  - Seidel-Morgenstern, Andreas
AU  - Petkovska, Menka
PY  - 2017
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3814
AB  - Deliberate periodic operations have been recognized as one way of process intensification for several decades. Special attention has been dedicated to possible improvements of chemical reactor performance through periodic modulation of one or more inputs. In our previous investigations we have developed a new, nonlinear frequency response (NFR) method, as a fast and easy analytical method for evaluating the performance of forced periodically operated chemical reactors. The NFR method is based on nonlinear frequency response analysis and the concept of higher order frequency response function (FRFs) [1]. In its essence the method is approximate and it is limited to analysis of stable, weakly nonlinear systems. The method gives an answer whether, and in which cases, it is possible to obtain process improvement through periodic operation. It also gives an approximate quantitative estimate of the improvement. In addition, the method enables choosing the best forcing parameters of the modulated input(s) (frequency, amplitude and, for multiple input modulation, the phase difference between the input waves).
The NFR method was originally developed for sinusoidal forcing function(s) [1]. Recently, it was extended to a general case which is applicable for any shape of the periodic input modulation, by expanding the input function into Fourier series and taking into account only a finite number of harmonics [2]. This opens a new possibility of choosing the best shape of the input wave, as well.
In this paper, the NFR method is used to evaluate the performance of a forced periodically operated adiabatic continuous stirred tank reactor (CSTR) in which an exothermal reaction of hydrolysis of acetic acid anhydride to acetic acid takes place [3]. The analysisis performed for periodic modulations of the acetic anhydride concentration in the feed stream, around a previously established optimal steady state. Different shapes of the input forcing function (sinusoidal, square-wave, triangle, saw-tooth,…) were analyzed, in order to determine the best strategy of performing periodic operation. The acetic acid yield is used as a measure of the reactor performance. The increases of the product yield (relative to the steady-state value) for different shapes of the forcing function are compared. Finally, the best forcing strategy (regarding the shape, frequency and amplitude of the input wave) is chosen to be applied for experimental investigation in a lab-scale adiabatic CSTR.
C3  - 10th World Congress of Chemical Engineering (WCCE10), Barcelona, Spain
T1  - Comparison of possible improvements of a periodically operated adiabatic CSTR with inlet concentration modulation for different shapes of the forcing function
UR  - https://hdl.handle.net/21.15107/rcub_cer_3814
ER  - 

@conference{
author = "Nikolić, Daliborka and Felischak, Matthias and Seidel-Morgenstern, Andreas and Petkovska, Menka",
year = "2017",
abstract = "Deliberate periodic operations have been recognized as one way of process intensification for several decades. Special attention has been dedicated to possible improvements of chemical reactor performance through periodic modulation of one or more inputs. In our previous investigations we have developed a new, nonlinear frequency response (NFR) method, as a fast and easy analytical method for evaluating the performance of forced periodically operated chemical reactors. The NFR method is based on nonlinear frequency response analysis and the concept of higher order frequency response function (FRFs) [1]. In its essence the method is approximate and it is limited to analysis of stable, weakly nonlinear systems. The method gives an answer whether, and in which cases, it is possible to obtain process improvement through periodic operation. It also gives an approximate quantitative estimate of the improvement. In addition, the method enables choosing the best forcing parameters of the modulated input(s) (frequency, amplitude and, for multiple input modulation, the phase difference between the input waves).
The NFR method was originally developed for sinusoidal forcing function(s) [1]. Recently, it was extended to a general case which is applicable for any shape of the periodic input modulation, by expanding the input function into Fourier series and taking into account only a finite number of harmonics [2]. This opens a new possibility of choosing the best shape of the input wave, as well.
In this paper, the NFR method is used to evaluate the performance of a forced periodically operated adiabatic continuous stirred tank reactor (CSTR) in which an exothermal reaction of hydrolysis of acetic acid anhydride to acetic acid takes place [3]. The analysisis performed for periodic modulations of the acetic anhydride concentration in the feed stream, around a previously established optimal steady state. Different shapes of the input forcing function (sinusoidal, square-wave, triangle, saw-tooth,…) were analyzed, in order to determine the best strategy of performing periodic operation. The acetic acid yield is used as a measure of the reactor performance. The increases of the product yield (relative to the steady-state value) for different shapes of the forcing function are compared. Finally, the best forcing strategy (regarding the shape, frequency and amplitude of the input wave) is chosen to be applied for experimental investigation in a lab-scale adiabatic CSTR.",
journal = "10th World Congress of Chemical Engineering (WCCE10), Barcelona, Spain",
title = "Comparison of possible improvements of a periodically operated adiabatic CSTR with inlet concentration modulation for different shapes of the forcing function",
url = "https://hdl.handle.net/21.15107/rcub_cer_3814"
}

Nikolić, D., Felischak, M., Seidel-Morgenstern, A.,& Petkovska, M.. (2017). Comparison of possible improvements of a periodically operated adiabatic CSTR with inlet concentration modulation for different shapes of the forcing function. in 10th World Congress of Chemical Engineering (WCCE10), Barcelona, Spain.
https://hdl.handle.net/21.15107/rcub_cer_3814

Nikolić D, Felischak M, Seidel-Morgenstern A, Petkovska M. Comparison of possible improvements of a periodically operated adiabatic CSTR with inlet concentration modulation for different shapes of the forcing function. in 10th World Congress of Chemical Engineering (WCCE10), Barcelona, Spain. 2017;.
https://hdl.handle.net/21.15107/rcub_cer_3814 .

Nikolić, Daliborka, Felischak, Matthias, Seidel-Morgenstern, Andreas, Petkovska, Menka, "Comparison of possible improvements of a periodically operated adiabatic CSTR with inlet concentration modulation for different shapes of the forcing function" in 10th World Congress of Chemical Engineering (WCCE10), Barcelona, Spain (2017),
https://hdl.handle.net/21.15107/rcub_cer_3814 .