Economical biogas direct methanation to pipeline grade natural gas via structured Ni based inverse catalyst

Biogas upgrading to pipeline-grade methane (>95% CH₄) represents a critical pathway for enhancing the utilization and value of biogas. Direct methanation of biogas is promising, but due to the performance limitations of conventional nickel-based methanation catalysts, reactant circulating or multi-stage process is required as engineering compensation. Here, through process simulation and economic analysis, we demonstrate substantial economic benefits of the single-stage methanation process over conventional routes in terms of both capital investment and operation costs. A structured inverse catalyst with CeZrO_x/Ni inverse configuration grown on porous Ni-foam featuring specific surface area and water removal enhancements over powder inverse catalyst is developed and realizes scale-up. The remarkable low-temperature activity of the structured inverse catalysts achieves a near-equilibrium conversion of 97.8% CO₂ in biogas, allowing the production of pipeline-grade methane through the single-stage biogas methanation process. With the innovation of catalysts and process, the price of low-carbon methane produced from biogas with industrial by-product hydrogen is competitive with natural gas.