It is understood that it is necessary to reduce the use of natural gas for power generation to control CO2 emissions and to decrease its extraction from the earth. We report the advantages of a Dual Function Material (DFM) that utilizes the energy in the effluent of a natural gas fired power plant, captures the CO2 and in a second step catalytically converts it to synthetic natural gas which is recycled to the plant for re use. This is accomplished by using stored hydrogen generated via water electrolysis from excess renewable energy. This closes the carbon cycle, decreases the net input of natural gas while using stored renewable energy. This new technology overcomes the energy penalties associated with the use of aqueous liquid amines in the Carbon Capture and Sequestration technology (CCS). DFM is composed of an alkaline adsorbent and a catalyst both dispersed on a high surface area carrier. The process is carried out at ~ 300oC in a power plant simulated flue gas containing O2 and steam. Methanation catalysts Ruthenium, Rhodium and Nickel in combination with adsorbents were tested in a 2-step process of: 1. adsorbing CO2 followed by 2. addition of renewable H2 to quantify the methane generated. Thermogravimetric analysis was used to screen new materials to measure the CO2 adsorption capacity and the rate of hydrogenation to synthetic natural gas (CH4). Ruthenium showed the best performance as measured by rapid and complete methane production. Rhodium is a good alternative, but its high cost makes it economically unattractive. Nickel suffers from poor reducibility after the O2 containing-CO2 capture step. The Al2O3 supported adsorbents (“Na2O”, CaO, “K2O” and MgO) were tested in combination with Ru. “Na2O” and CaO adsorbents showed the best adsorption capacity and kinetics towards methane production making them the adsorbents of choice.

New catalysts, adsorbents, and carriers for in-situ conversion of CO2 to synthetic natural gas with dual function materials

2019 Spring National Meeting

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