Methanation reaction methods utilizing enhanced catalyst formulations and methods of preparing enhanced methanation catalysts

摘要

Enhanced mixed metal catalysts are provided which allow high conversions of carbon dioxide to methane, in some cases up to about 100% conversion. Methods of preparing enhanced mixed metal catalysts comprise a series of steps involving combining nickel and chromium salts with a nucleation promoter in a base environment to form a gel, allowing the gel to digest to form a solid and a mother liquor, isolating the solid, washing the solid, drying the solid, and thermally treating the solid to form a nickel-chromium catalyst. Methanation processes using the catalysts are also provided. The enhanced mixed metal catalysts provide more efficient conversion and lower operating temperatures for carbon dioxide methanation when compared to conventional methanation catalysts. Additionally, these enhanced catalyst formulations allow realization of higher value product from captured carbon dioxide.

主权项

1. A methanation reaction process comprising the steps of:
preparing a nickel-chromium catalyst, wherein the step of preparing comprises the steps of:
(a) combining a nickel(II) salt and a chromium(III) salt with a nucleation promoter and ammonium hydroxide to form a gel, the gel comprising a solid and a liquid;(b) allowing the gel to digest to form a mother liquor and an isolatable solid;(c) isolating the solid from the mother liquor;(d) washing the solid;(e) drying the solid;(f) thermally treating the solid to form the nickel-chromium catalyst; wherein steps (a)-(f) result in a nickel/chromium ratio of about 98:2 to about 50:50 in the nickel-chromium catalyst; providing a single reactor vessel; continuously introducing carbon dioxide and hydrogen gas into the single reactor vessel over a fixed bed, the fixed bed comprising the nickel-chromium catalyst; allowing the carbon dioxide and hydrogen gas to react in the single reactor vessel at a conversion rate in the presence of the nickel-chromium catalyst at a reaction temperature; maintaining the reaction temperature in the single reactor vessel at about 205° C. to about 220° C. by controlling a flow rate of one of the carbon dioxide and the hydrogen gas fed to the single reactor vessel; and wherein the conversion rate to methane is about 25 percent to about 100 percent.