A New Approach to Modeling Solid Oxide Cell Reactors with Multiple Stacks for Process System Simulation

Abstract

Reactors with solid oxide cells (SOC) are highly efficient electrochemical energy converters, which can be used for electricity generation and production of chemical feedstocks. The technology is in an upscaling phase, demanding development of strategies for robust and efficient operation or large SOC reactors and plants. The present state of the technology requires reactors with multiple stacks to achieve the appropriate power. This study aims to establish and apply a simulation framework to investigate process systems containing SOC reactors with multiple stacks focusing especially on the operating behavior of SOC reactors under transient conditions, by observing the performance of all cells in the reactor. For this purpose, a simulation model of the entire SOC reactor consisting of multiple stacks, pipes, manifolds, and thermal insulation was developed. After validation on stack and reactor level, the model was used to investigate the fundamental behavior of the SOC reactors and the individual stacks in various operation modes. Additionally, the influences of local degradation and reactor scaling on the performance were examined. The results show that detailed investigation of the reactors is necessary to ensure operability and to increase efficiency and robustness. Furthermore, the computing performance is sufficient to develop and validate system controls.

Operation strategies for a flexible megawatt scale electrolysis system for synthesis gas and hydrogen production with direct air capture of carbon dioxide

“…By using DLR's modeling framework TEMPEST, 13 a model of a flexible electrolysis plant was created. This was used to define standard operating points and subsequently develop operating strategies.…”

“…Model set up, validation and operating analysis for the SOC reactor are presented by the authors in ref. 13. The stacks are arranged in six towers with four stacks each.…”

“…The simulation results described in this work were acquired using DLR's modelling and simulation framework TEMPEST, 12,13 which is designed for transient simulations of process systems with electrochemical reactors. Implemented in Modelica®, 14 it can be used for simulation studies with various technologies such as solid oxide cells with an electrode and electrolyte support as well as alkaline water electrolysis.…”

“…11 In this study, DLR's transient modelling framework TEMPEST 12,13 is used, which is described in the Methodology section and allows detailed coverage of all stacks in modular SOC reactors as well as analysis of the complete process system. Here, a model of a commercial SOC reactor with 24 stacks is utilized, which was parameterized and validated 13 based on experiments on DLR's SOEC test rig named GALACTICA with a maximum electrical power of 120 kW. The experiments and former simulations lead to a series of promising stationary operating points.…”

Transient Solid Oxide Cell Reactor Model Used in rSOC Mode-Switching Analysis and Power Split Control of an SOFC-Battery Hybrid

“…The 1D+1D SOC dynamic multi-reactor model includes the individual SOC reactors, piping and insulation, and is implemented in the in-house developed transient energy process system simulation framework TEMPEST (1,2). The model couples the transient material and energy balances with electrochemistry, internal reforming kinetics, heat transfer, and flow distribution.…”