流化床中甲烷在活性炭上裂解制氢研究

Hydrogen Production by Methane Decomposition over Activated Carbon in a Fluidized-Bed Reactor

采用几种工业成型的活性炭为催化剂,在流化床反应器中研究了甲烷裂解制氢的反应,详细考察了流化床操作条件及活性炭性质对甲烷裂解反应的影响。结果表明:在流化床中甲烷初期转化率最高,随着反应进行由于不断积炭转化率逐渐降低直至一个平稳的阶段。这与在固定床反应器中的规律相似,但是在流化床中甲烷表现了较高的裂解初始速率。流化床操作条件对甲烷裂解影响很大,流速增大甲烷整体转化率降低;温度升高提高了初始转化率,但活性炭稳定性降低;根据Arrhenius方程确定的反应活化能为134.1 kJ/mol。较小粒度的活性炭,其甲烷裂解初始速率较高,但整体催化性能变化不大。流化床反应器能实现失活催化剂的移出和新鲜催化剂的加入,适用于大规模的甲烷在活性炭上裂解制氢反应体系。

Using several commercial activated carbons as catalysts, hydrogen preparation by methane decomposition in a fluidized-bed reactor was studied. The effects of the operation conditions of fluidized-bed reactor and the properties of activated carbon were investigated in detail, Methane conversion shows the highest value in the initial stage and then drops to a steady state because of the carbon deposition, which shows the similar performance as that in a fixed-bed reactor. While there is a higher initial methane decomposition rate found in the fluidized-bed reactor. The operation conditions of the fluidized-bed reactor have great influence on methane decomposition. With increasing of the gas flow rate, methane conversion decreases; the initial methane decomposition rate increases with temperature increasing while the stability of activated carbon becomes much poorer. The activation energy of methane decomposition over activated carbon in a fluidized-bed reactor is 134.1kJ/mol according to Arrhenius equation in this experiment. Smaller carbon particle is favor to methane decomposition at the initial stage while the whole catalytic performance during the process is similar to other size of particles. Fluidized-bed reactor can introduce the fresh catalysts and withdraw the deactivated ones continually which is suitable for the reaction system of hydrogen production by methane decomposition over carbons in largescale.