Research On Hydrogen Production From Dimethyl Ether For Solid Oxide Fuel Cells

Due to its high heat value and pollution-free combustion products,Hydrogen is considered as the clean energy for future.Using hydrogen as a fuel,can effectively deal with the problem of traditional fossil energy resources depletion and environmental pollution.Compared with other hydrogen feedstock,dimethyl ether?DME?exhibits a lots of advantages,such as high energy density,non-toxic,non-corrosive,convenient storage and transportation,therefore DME is considered as an ideal hydrogen carrier for hydrogen fuel cell vehicles.The storage and transportation of DME can be compatible with existing LPG facilities,it is suitable for mobile hydrogen production.Compared with other hydrogen production methods,the DME steam reforming?DME SR?to hydrogen is better for its mild reaction conditions,less by-products and low cost etc.In this paper the copper based catalysts were prepared by co-precipitation method and impregnation method,the reaction conditions of hydrogen production from DME SR was investigated too.Combining the thermodynamic simulation results of DME SR by Aspen Plus,the evaluation and characterization of catalysts for DME SR were investigated.The conclusion are as followed:1.The thermodynamic simulation results indicated that the reacting temperature exhibited more effect on DME SR relative to the pressure and water/carbon ratio.Through the thermodynamic simulation the reaction temperature is 500⁶00 ?,water/carbon ratio is 5.0¹0.0,and the reaction pressure is atmospheric pressure.2.For copper zinc?Cu/Zn=2:1?catalyst,when the aging temperature is 70 ? it showed better catalytic activity;?-Al₂O₃ and the Cu-based catalyst?with a weight ratio 4:1?were mixed and filled into the reactor.The DME conversion rate and the hydrogen yield was 94.75% and 79.44% respectively under 550 ?.The reason for the good catalytic activity for DME SR could be the active sites for DME hydrolysis and methanol reforming were close with the mixed filling way,thereby promoting the reaction to the positive side.3.Relative to LZ series support,the catalysts with weak acidic ?-Al₂O₃ support exhibited better catalytic activity and stability.When the catalyst impregnated C u as the active component with loading range of 5.9 wt.%⁷.4 wt.%,the catalyst showed both low temperature catalytic activity and high temperature stability for DME SR.When the catalyst was 2Cu-1Zn/?-Al₂O₃,after running 97 h,the hydrogen yield decreased from 87.0% to 60.0%.Adding Cr to 2C u-1Zn/?-Al₂O₃,that was 6C u-3Zn-1Cr/?-Al₂O₃ showed better stability.After running 100 h the hydrogen yield decreased from 86.0% to 83.0%,only decline three percent.4.Combined with thermodynamic simulation results and experimental results,the optimized reaction conditions is temperature 550 ?,space velocity 125⁵00 mL/?g·h?,and water/carbon ratio 5.0,respectively.