Study On Higher Alcohols From Syngas Over Novel CuCo Catalysts

Higher alcohols, which can be used as fuels, gasoline additives, chemicals andchemical raw materials show good application value and application prospect. In thisthesis, a series of zirconia-supported LaCo1-xCuxO3perovsktie-type oxides wereproduced as catalyst precursor base on the own characteristics of ZrO2, La2O3andCuCo catalysts in higher alcohol synthesis, the catalytic performance of the catalystswith different Cu content, different perovsktie-type oxides content and differentreaction conditions were investigated.A series of16%LaCo1-xCuxO3/ZrO2(x=0,0.1,0.2,0.3) catalysts withdifferent Cu content were prepared by impregnating ZrO2with lanthanum, cobaltand copper nitrate and citrate acid, and the prepared samples were characterizedby XRD, TEM and H2-TPR techniques. The synthesis of alcohol from syngas wasperformed in a stainless-steel continuous fixed-bed flow micro-reactor. Afterreduction, the catalyst precursor favored to form nanoparticles of Co-Cu alloyhighly dispersed on ZrO2and modified with La2O3(Co-Cu/ZrO2-La2O3), then theprecursor would form into the structure of Co2C-Cu/ZrO2-La2O3during thereaction. The activity tests indicated that the catalyst showed excellent selectivityto alcohols and higher alcohols. Under the reaction conditions of310oC,3MPa,H2/CO=2, a space velocity of3900h-1, the selectivity to alcohols of16%LaCo0.7Cu0.3O3/ZrO2was43.4%, and C2+alcohols account for82.3%of theliquid product. In the running period of200h, the catalyst maintains its goodperformance. The metal nanoparticles of Cu-Co alloy together with ZrO2modifiedwith La2O3contributed to the excellent selectivity to alcohols and higher alcohols,and the very good stability.y%LaCo0.7Cu0.3O3/ZrO2(y=12,16,18) were prepared by using the citratecomplexation method, the effect of perovsktie-type oxides content on theperformance in higher alcohol synthesis had also been investigated. The activitytests showed that the selectivity to higher alcohols decreased with the increase ofthe perovskite oxides content. Aggregation of perovskite precursor would easily totake place on the surface of ZrO2with increasing perovskite content, and thedispersion of Cu-Co alloy particles is poor which affect the selectivity to higher alcohols of the catalyst.The effect of pressure on the performance of16%LaCo0.7Cu0.3O3/ZrO2inhigher alcohol synthesis were investigated. The results showed that increasingpressure improved CO conversion and selectivity to alcohols effectively, inhibitedthe production of hydrocarbons simultaneously. The alcohols distributions showedthat C2+alcohols content in the liquid products and space-time yield of alcoholsincreased under higher pressure.