Recent Advances in Catalysis for Methanation of CO2 from Biogas

Abstract

Biogas, with its high carbon dioxide content (30–50 vol%), is an attractive feed for catalytic methanation with green hydrogen, and is suitable for establishing a closed carbon cycle with methane as energy carrier. The most important questions for direct biogas methanation are how the high methane content influences the methanation reaction and overall efficiency on one hand, and to what extent the methanation catalysts can be made more resistant to various sulfur-containing compounds in biogas on the other hand. Ni-based catalysts are the most favored for economic reasons. The interplay of active compounds, supports, and promoters is discussed regarding the potential for improving sulfur resistance. Several strategies are addressed and experimental studies are evaluated, to identify catalysts which might be suitable for these challenges. As several catalyst functionalities must be combined, materials with two active metals and binary oxide support seem to be the best approach to technically applicable solutions. The high methane content in biogas appears to have a measurable impact on equilibrium and therefore CO2 conversion. Depending on the initial CH4/CO2 ratio, this might lead to a product with higher methane content, and, after work-up, to a drop in-option for existing natural gas grids.

Removal of carbon dioxide using zeolitic imidazolate frameworks: Adsorption and conversion via catalysis

“…The conversion of CO 2 into hydrocarbons via hydrogenation is a promising method of making waste into valueadded materials. [10,[264][265][266][267][268][269][270][271][272][273] This reaction can solve the environmental and energy issues caused due to CO 2 emissions. Hydrogenation of CO 2 can be used to synthesize valuable compounds: (1) hydrocarbons, such as methane (CH 4 , the reaction can be called methanation), [270,274] olefins, and gasoline, or (2) other compounds, such as formic acid (HCOOH), alcohol (e.g., methanol), and carbon monoxide (CO).…”

“…Hydrogenation of CO 2 can be used to synthesize valuable compounds: (1) hydrocarbons, such as methane (CH 4 , the reaction can be called methanation), [270,274] olefins, and gasoline, or (2) other compounds, such as formic acid (HCOOH), alcohol (e.g., methanol), and carbon monoxide (CO). [10,[264][265][266][267][268][269][270][271][272][273] Hydrogenation can be promoted via electrochemical, [275] thermo-catalysis, [276] and photo/thermal [277] methods. ZIF materials are promising catalysts in terms of efficiency and selectivity among several catalysts.…”

A Review on Removal of Carbon Dioxide (CO2) using Zeolitic Imidazolate Frameworks: Adsorption and Conversion via Catalysis

“…The conversion of CO2 into hydrocarbons via hydrogenation is a promising method of making waste into value-added materials [10,[261][262][263][264][265][266][267][268][269][270] . This reaction can solve the environmental and energy issues caused due to CO2 emissions.…”

“…This reaction can solve the environmental and energy issues caused due to CO2 emissions. Hydrogenation of CO2 can be used to synthesize valuable compounds; 1) hydrocarbons, such as methane (CH4, the reaction can be called methanation) [267,271] , olefins, and gasoline, or 2) other compounds, such as formic acid (HCOOH), alcohol (e.g., methanol), and carbon monoxide (CO) [10,[261][262][263][264][265][266][267][268][269][270] . Hydrogenation can be promoted via electrochemical [272] , thermo-catalysis [273] , and photo/thermal [274] methods.…”

Biogas Upgrading by CO2 Methanation with Ni-, Ni–Fe-, and Ru-Based Catalysts

“…This research also showed that the introduction of H 2 S traces along with the feed stream led to a fast drop in CO 2 conversion and CH 4 selectivity. The presence of CH 4 and H 2 S clearly affects the activity of methanation catalysts, but this influence depends on the catalyst composition and reactions conditions [39]. A pilot-scale experimental setup highlighted the importance of controlling the exothermicity of the Sabatier reaction [9,40].…”