微波辐射下活性炭催化甲烷裂解制氢

Microwave-assisted catalytic decomposition of methane over activated carbon for hydrogen production

采用石英管固定床反应器,在微波加热条件下分别研究了气氛条件、甲烷分压以及铁粉对活性炭催化裂解甲烷的影响,并与传统电加热方式下的甲烷裂解特性进行了对比研究。结果表明,活性炭在不同气氛条件下表现出不同的升温特性,活性炭在氮气和氢气中的升温效果优于甲烷气氛。铁粉的掺入有利于提高活性炭反应温度,从而促进甲烷的转化率。对反应前后的活性炭进行了扫描电镜和比表面积分析,结果表明甲烷裂解后产生的大量积炭覆盖在活性炭表面,导致比表面积和孔容减小,平均孔径增大。进而推测活性炭活性降低的主要原因是由于积炭堵塞了活性炭微孔,减少了甲烷与活性炭微孔中的活性中心位的接触。

The microwave-assisted pyrolysis of methane over an activated carbon （AC） was studied in a fixed-bed quartz-tube reactor. The effects of reaction atmosphere,methane partial pressure and iron powder on methane conversion were investigated. The AC showed better microwave heating performance in N2 or H2 atmosphere than that in CH4 atmosphere. Iron powder could promote microwave heating of the AC,leading to higher methane conversion. SEM results indicated that carbon would deposit on the surface of the AC during methane decomposition. The spent AC had lower surface area,lower pore volume,and larger pore diameter than those of fresh ones,which suggested that carbon deposition in the pores caused deactivation of the AC.