545515 The Feasibility of the Thermocatalytic Conversion of CO2 into Synthetic Natural Gas (SNG)

Monday, June 3, 2019: 2:42 PM
Republic ABC (Grand Hyatt San Antonio)
Sogol Mottaghi-Tabar, Robert Currie, Yichen Zhuang and David Simakov, Chemical Engineering, University of Waterloo, Waterloo, ON, Canada

The synthetic natural gas (SNG) generation process discussed in this talk relies on the thermocatalytic Sabatier reaction:

CO2 + 4H2 = CH4 + 2H2O + heat (165 kJ/mol)

The main idea is to convert the CO2 contained in waste streams (e.g. cement plant flue gas, landfill gas) into synthetic natural gas (SNG) on site using electrolytic hydrogen generated using renewable or low carbon footprint electricity.

Although CO2 separation technologies are already commercially available (e.g. pressure swing adsorption (PSA) and membrane separation), the captured CO2 has to be compressed on site, transported, and eventually stored or utilized somehow. Storing the captured CO2 in geological formations could be prohibitively expensive. Some of that captured CO2 can be utilized in the chemical and food industry. However, these markets are limited in their capacity to absorb megatons of separated CO2 and the capital and operating costs associated with the CO2 compression and transportation may not be recoverable.

The approach discussed in this talk is an innovative and sustainable alternative that goes beyond conventional CO2 capture and storage (CCS), relying on CO2 capture and utilization (CCU) instead. The hydrogen required for the reaction is provided by water electrolysis using renewable or low carbon footprint electricity. The water and heat generated in the process are recuperated to improve the process efficiency. Oxygen (O2), which is a byproduct of water electrolysis can be utilized as well. With a proper postreatment, such process would produce a pipeline quality SNG which can be directly injected into the existing natural gas infrastructure, replacing the fossil natural gas.

Technological issues related to catalysis, reactor design and system integration are outlined in this talk. The results of the catalytic performance evaluation of Ni- and Ru-based catalysts are briefly presented followed by numerical simulations and a lab-scale experimental proof-of-concept of a novel reactor configuration. Design of the entire SNG production system including upstream and downstream treatment is also briefly discussed. The focus is on the technological and economic feasibility of this conversion pathway.

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See more of this Session: Conversion Processes for Energy and Chemicals
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