负载碳酸钾煤焦上CO甲烷化反应的研究

Methanation of CO over coal char loaded with K_2CO_3

在加压固定床反应器中,考察了负载碳酸钾的府谷煤热解半焦和不同气化率的部分气化半焦对CO甲烷化反应的催化性能。结果表明,原煤热解半焦和脱灰煤热解半焦的甲烷化活性都很低,而负载10%(质量分数)碳酸钾的热解半焦甲烷化活性明显提高,甲烷收率可达30%。负载碳酸钾的热解半焦水蒸气气化反应速率与碳气化率呈"火山"型关系曲线,在碳气化率为22%时达到极大值。在气化反应速率较高时得到的部分气化半焦上,甲烷化反应速率较低。利用红外光谱对半焦官能团进行分析,发现在热解过程中,碳酸钾和煤发生反应形成C-O-K复合物,在1100 cm-1附近出现特征振动峰,该峰的强度与碳气化反应速率成正比。不同气化率半焦经过甲烷化反应后,红外光谱谱图中C-O-K峰强度不同程度增大。

The catalytic performance of coal char loadde with potassium carbonate on the CO me thanation r eaction was investigated in a pressurized fixed bed reactor.The rse ults hs ow that the catalytic activ ities of raw coal pyrolysis char and demineralized coal pyrolysis char are very low, whiel with lao ding 10% potassium carbonate, the catalytic activity of chars increases obviously and the yield of methane reaches to 30%.The gasification rate changes with the progress of carbon conversion and has a maximum value at a carbon conversion around 22%.The analysis by FT-IR indicates that the interaction of potassium carbonate with coal can form C-O-K complexes during pyrolysis at 700℃, with an infrared band around 1 100 cm-1 .The intensity of this band is found to be proportional to the steam gasification rate of the carbon.After reaction in CO-H2 mixture gas at 700℃for 180 min, the intensity of C-O-K vibration increases more or less.