入口气组分对质子交换膜燃料电池柴油水蒸气重整制氢流程的影响

考察了Ni--Yb/γ--Al2O3(Ni 16%,Yb 5%,质量分数)催化剂,入口气中添加不同组分(CO2、H2和CH4)对柴油低/高温水蒸气重整过程中转化率及重整率的影响,以及添加CO2入口气对质子交换膜燃料电池柴油水蒸气重整制氢流程中后续的CO水气变换和深度去除CO过程的影响.结果表明:入口气中添加CO2或H2进一步提高了柴油在低温(400～500℃)水蒸气重整反应中的转化率(95%),能够为后续的高温(550～750℃)水蒸气重整过程提供CH4代替柴油作为重整原料,从而显著抑制了积碳.入口气中添加H2对高温水蒸气重整有抑制作用,添加CH4不利于提高柴油转化率.入口气中添加CO2时,气碳摩尔比约为0.54时柴油转化率最佳,但重整产物中CO含量会增加,因而后续CO水汽变换过程的空速需降低以便保证CO去除率,添加CO2对最后深度去除CO过程(两段选择甲烷化法)无明显影响.

Influence of inlet gas components on the diesel steam reforming of proton exchange membrane fuel cells for hydrogen production

This paper investigated the rates of diesel conversion and reforming over Ni-Yb/γ-Al2O3 catalyst(Ni 16%,Yb 5%) in low/high temperature diesel steam reforming with different inlet gases(CO2,H2 and CH4) as well as the influences of CO2 inlet gas on water-gas-shift and CO deep removal,which are the follow-up processes of the hydrogen production flowsheet based on diesel steam reforming for proton exchange membrane fuel cells(PEMFC).CO2 or H2 improves diesel conversion(>95%) in low temperature(from 400 to 500 ℃) diesel steam reforming,which can let CH4 instead of diesel to participate high temperature(from 550 to 750 ℃) steam reforming,so that carbon deposition can be resisted obviously.However H2 shows depression on the high temperature steam reforming,and CH4 inlet gas depresses diesel conversion.When the molar ratio of gas to the total carbon of diesel is around 0.54,CO2 inlet gas shows the best improvement on diesel conversion;however the CO content increases in the product gas,so the gas-hourly-space-velocity of CO water-gas-shift should be reduced to reach the required CO removal ratio.There is no obvious influence on the two-stage methanation for CO deep removal.