内在钾元素对玉米芯超临界水气化制氢过程的影响

Influence of Inherent Potassium in Corncob on Hydrogen Production with Supercritical Water Gasification

为研究玉米芯中内在钾元素对其超临界水气化(SCWG)过程的影响,采用水洗方式对钾元素进行了脱除.对水洗样中的无机成分和有机成分进行了分析,结果表明这一方法能有效脱除玉米芯中的钾,并能保持玉米芯有机成分的稳定.利用压力釜反应器对玉米芯原样和水洗样进行了不同反应温度、不同反应压力、不同反应停留时间下的SCWG实验.实验结果表明,玉米芯中钾元素的存在促进了SCWG反应产物中氢气的生成.提高反应压力或延长反应时间,均强化K对H2生成的促进作用.内在钾元素对气体产量和气化率的影响与温度有关,低温时促进气化,而高温时抑制气化.此外,对水洗样分别回添KCl和KOH进行了SCWG反应实验,结果表明回添的KCl和KOH均阻碍氢气的产生和玉米芯的气化.因此,玉米芯内在钾元素在SCWG过程中的作用方式与直接添加钾成分时有所区别.

Inherent potassium in the corncob was removed by means of water-leaching and the analysis on the inorganic composition and the organic composition of the water-leached corncob was performed.The results show that almost all potassium in the corncob could be removed and there was little change in the organic composition of the corncob after water-leaching.The experiments on the corncob supercritical water gasification（SCWG） with different reaction temperatures,reaction pressures and residence time were conducted in a high-pressure autoclave.The results indicate that the inherent potassium in the corncob will facilitate hydrogen generation.The greater reaction pressure and the reaction time can both promote the effect of the inherent potassium on hydrogen production.The influences of inherent K on total gas yield and gasification efficiency were related to the reaction temperature.In addition,the experiments on the water-leached samples with added KCl or KOH show that KCl or KOH hindered hydrogen generation and corncob gasification.It is likely that the effect of the inherent potassium in the corncob on the SCWG was different from that of the added potassium.