Design and Simulation of Novel Sabatier Reactors for the Thermocatalytic Conversion of CO2 into Renewable Natural Gas
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Date
2019-04-22
Authors
Currie, Robert
Journal Title
Journal ISSN
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Publisher
University of Waterloo
Abstract
Producing synthetic chemicals and fuels using CO2 as a feedstock through the thermocatalytic hydrogenation of CO2 via the Sabatier reaction to produce synthetic CH4 is both a CO2 emissions reduction strategy and an intermittent energy storage solution. A simulation-based study of novel Sabatier reactor configurations was performed to study the effect a distributed H2 supply would have on Ni-based catalyst deactivation and to optimize the production of CH4 for the purposes of evaluating the economic feasibility of a renewable natural gas production facility. First, a heat-exchanger type, molten salt-cooled membrane reactor is analyzed using a transient mathematical model that accounts for dynamic catalyst deactivation. The simulation results showed significantly lower catalyst deactivation rates in the membrane reactor due to the distributed H2 supply that results in more uniform temperature distribution. The model predicts that, with a proper selection of operating parameters, it is possible to achieve CO2 conversions over 95% over extended periods of operation (10,000 h). Next, a heat-exchanger type, actively cooled Sabatier reactor is analyzed using a transient mathematical model to assess its techno-economic feasibility. Effect of cooling fluid, space velocity, and cooling rate on reactor performance was investigated. Simulation results show that with a proper selection of operating parameters, it is possible to achieve CO2 conversions more than 90% with 100% CH4 selectivity over extended periods of operation for a renewable natural gas production cost of $15/GJ with electricity at $0.05/kWh.
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Keywords
CO2 conversion, renewable natural gas, Sabatier reactor, packed bed reactor, membrane reactor, catalyst deactivation, distributed H2 supply