Renewable Energy Hydrogen

PROCESS MODEL FOR THE PRODUCTION OF SYNGAS VIA HIGH TEMPERATURE CO-ELECTROLYSIS

Authors: M. G. McKellar J. E. O' Brien C. M. Stoots G. L. Hawkes
 
Abstract: A process model has been developed to evaluate the potential performance of a large-scale high-temperature coelectrolysis plant for the production of syngas from steam and carbon dioxide. The coelectrolysis process allows for direct electrochemical reduction of the steam � carbon dioxide gas mixture, yielding hydrogen and carbon monoxide, or syngas. The process model has been developed using the HYSYS systems analysis code. Using this code, a detailed process flowsheet has been defined that includes all the components that would be present in an actual plant such as pumps, compressors, heat exchangers, turbines, and the electrolyzer. Since the electrolyzer is not a standard HYSYS component, a custom one-dimensional coelectrolysis model was developed for incorporation into the overall HYSYS process flowsheet. The 1-D coelectrolysis model assumes local chemical equilibrium among the four process-gas species via the shift reaction. The electrolyzer model allows for the determination of coelectrolysis outlet temperature, composition (anode and cathode sides), mean Nernst potential, operating voltage and electrolyzer power based on specified inlet gas flow rates, heat loss or gain, current density, and cell area-specific resistance. The one-dimensional electrolyzer model was validated by comparison with results obtained from a fully 3-D computational fluid dynamics model developed using FLUENT, and by comparison to experimental data. This paper provides representative results obtained from the HYSYS flowsheet model for a 300 MW coelectrolysis plant, coupled to a high-temperature gas-cooled nuclear reactor. The coelectrolysis process, coupled to a nuclear reactor, provides a means of recycling carbon dioxide back into a useful liquid fuel. If the carbon dioxide source is based on biomass, the entire process would be climate neutral.
Publication Date: 01 Nov 2007
Report numbers: INL/CON-07-12818
DOE Contract number: DE-AC07-99ID-13727
Resource Type: Conference
Resource Relation: Conference: 2007 ASME International Mechanical Engineering Congress & Exposition,Chicago, IL, USA ,11/05/2007,11/10/2007
Research Organizations: Idaho National Laboratory (INL)
Sponsoring Organizations: USDOE
Country of Publication: United States
Language: English
Keywords relating to this report:
BIOMASS
CARBON DIOXIDE
CARBON MONOXIDE
CATHODES
CLIMATES
COMPRESSORS
COMPUTERIZED SIMULATION
CURRENT DENSITY
FLOWSHEETS
FLUID MECHANICS
GAS FLOW
HEAT EXCHANGERS
HYDROGEN
LIQUID FUELS
MECHANICAL ENGINEERING
REACTORS
RECYCLING
STEAM
SYSTEMS ANALYSIS
TURBINES

Subjects:
Related subjects:
HIGH-TEMPERATURE ELECTROLYSIS
NUCLEAR ENERGY
SYNTHETIC FUELS