Model-based optimal sizing and operation of electrochemical processes
Year: 2025
Type: book
Abstract: To reduce greenhouse emissions and defossilize the chemical, transportation, and energy sectors, electrochemical processes have gained attention in the last years as a sustainable alternative to fossil-based processes. However, their broader adaptation in the market necessitates optimization to become cost-competitive with the traditional methods. In this thesis, we explore how to reduce their costs via model-based analysis and optimization of their sizing and/or operation. First, we study the novel electrochemical hydrogen compression technology, which has emerged as an alternative to mechanical compression. We begin with the model development and assess the compressor performance for low to high-pressure levels. We identify operational and cost trade-offs and optimize the compressor sizing and operation for different target pressures at a device level to minimize the total cost by determining the optimal current density and temperature. The results show that the optimal operating points depend on the target pressure, and generally, higher current densities and lower temperatures are beneficial at higher pressure levels. Second, we investigate the possibility of integrating the electrochemical hydrogen compressor at a hydrogen refueling station as an alternative to the currently used mechanical compressor. We begin with the model development of three alternative hydrogen refuelling station configurations, which differ in the compression technology used: mechanical vs electrochemical vs combined. We optimize the sizing and operation of the compressors and the cascade-storage system by solving multi-stage dynamic optimization problems. The goal is to minimize the levelized cost of hydrogen dispensing. The results reveal that the electrochemical compressor can complement the mechanical compressor, but improvements in the energy demand are needed. Finally, we assess the potential of flexibilizing the electrochemical hydrogen peroxide synthesis, a recently proposed alternative to the traditional anthraquinone process, by taking advantage of the fluctuating electricity prices and alternating between two anodic reactions. We present two novel operational strategies at the anode: the switchable strategy, which allows switching between the oxygen evolution reaction and the hydrogen oxidation reaction, and the tunable strategy, which allows the oxygen evolution and hydrogen oxidation reaction to occur in parallel at the anode. We determine the optimal scheduling and compare the operational cost-benefits among the different strategies. Furthermore, we estimate the payout time for the additional investment of the novel strategies compared to the stand-alone water strategy. The results show that an important cost reduction can be achieved via switchable and tunable strategies, the extent of which depends on the assumed electricity and hydrogen prices.
Source: RWTH Publications (RWTH Aachen)
Author: Prokopou, Georgia Ioanna
Institution: RWTH Aachen University
Language: English
Subfield: Energy Engineering and Power Technology
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7106096662
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