Synthesis Of Liquid Hydrocarbons From Coalmine Drained Methane Via Syngas

In China, a large amount of coalmine drained methane was vented into theatmosphere during coal mining every year, resulting in not only a loss of valuablesource but also contribution to environment pollution. The study on theconversion of coalmine drained methane to liquid hydrocarbons via syngas wasconducted in this paper in order to found a feasible method for utilizing thecoalmine drained methane.According to the composition characteristics of the coalmine drained gas, anintegrated air partial oxidation with CO₂ reforming of methane process that candirectly utilize the methane, air and carbon dioxide in the drained gas, was firstproposed in this paper. A detailed study on this process was conducted. Based onthe principle that basic support and little metal particle are beneficial to inhibitcarbon deposition, Ni_xMg_1-xO solid solution catalyst was prepared. The influencesof catalyst preparation and reaction conditions on the catalytic performance weremainly investigated. The results showed that a synthesis gas with a H₂/CO ratiobetween 1.0 and ₂.0 can be successfully produced by CH₄-Air-CO₂ orCH₄-Air-CO₂-H₂O reaction and the NixMg1-xO solid solution catalyst exhibitedexcellent activity and stability.The single-pass Fischer-Tropsch synthesis with N₂-containing syngas thatwas produced from CH₄-Air-CO₂-H₂O reaction was also studied in fixed-bedreactor in this paper. The impacts of noble metal promoter on the properties andcatalytic performance of Co/Al2O3 catalyst were mainly investigated. The resultsindicated that the noble metal promoters not only significantly improved thereducibility of cobalt oxides to Co0 in Co/Al2O3 catalyst by hydrogen spilloverduring catalyst activation, but also maintained the number of active Co0 sites byenhancing Cod+ reduction during reaction. Temperature programmed surfacereaction (TPSR) results showed that the presence of noble metal promotersfacilitated the CO dissociation on active metallic Co sites, and thus remarkablyincreasing the hydrogenation activity. In addition, an initial study on thedeactivationof cobalt catalyst was also conducted.