KOH对低阶煤在超临界水中制取富氢气体的影响

EFFECT OF KOH ON CONVERSION OF LOW RANK COAL TO HYDROGEN-RICH GAS IN SUPERCRITICAL WATER

以超临界水介质中低阶煤制取富氢气体为目的,利用120 ml小型间歇反应装置,在KOH/煤为0.7％～10％(质量)、温度400～650℃、压力12～30 MPa、停留时间0～30 min的范围内,考察了KOH催化下操作参数对小龙潭褐煤反应特性的影响。结果表明,随着KOH/煤质量比的增加,煤转化率和气体产率升高。KOH/煤质量比为10％时,气相产物中H_2百分含量增加一倍,H_2产率提高1.7倍。升高反应温度可以使KOH的催化作用更显著。对比氮气气氛和超临界水中煤催化热解反应发现,反应温度为600℃时,添加相同量的KOH催化剂,氮气气氛下煤转化率升高4.4％(质量),SCW条件下煤转化率升高7.8％(质量),说明超临界水反应环境下KOH的催化作用更加明显。提高反应压力可以促使煤转化率和气体产率升高。与KOH添加量和温度相比,停留时间对H_2产率的影响较小,随着停留时间的延长,CH_4产率略有增加。

Conversion of a low rank coal to hydrogen-rich gas was performed in supercritical water (400～650℃, 12—30 MPa, 0—30min) in the presence of KOH. The effects of KOH/coal ratio and reaction conditions on both coal conversion and product yields were investigated. The yields of H_2 and CO_2 in gas product increases with the increases of KOH/coal weight ratio. The rise of temperature leads to an increase in the conversion of coal and the yield of hydrogen, and the catalytic performance of KOH is distinct at higher...