@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"
}
