煤焦加压水蒸气催化气化反应特性及甲烷释放规律研究

Catalytic gasification of coal char with steam and methane release at elevated pressure

以内蒙褐煤焦为研究对象,K2CO3为催化剂,在小型加压固定床上考察了反应温度、操作压力和水碳比对煤焦水蒸气气化反应过程中碳转化率、反应速率和甲烷浓度及其累计流量的影响。结果表明,随着反应温度的增加,碳转化率和反应速率显著增加,甲烷浓度及其累计流量也增加,表明甲烷化反应在600-700℃内仍受动力学控制。操作压力的提高,碳转化率和反应速率呈先增加后减小的变化趋势,而甲烷的浓度逐渐增加,其累计流量由常压下的2.4 mL逐渐增加至3.5 MPa下的43.2 mL。随着水碳比的增加,碳转化率和反应速率大幅增加,但是甲烷的浓度逐渐降低,甲烷的累计流量受反应速率和反应平衡的共同影响,呈先增加后减小的趋势。

The gasification reaction tests of Inner Mongolia lignite char with K_2CO_3 as catalyst were carried out in a pressured fixed-bed reactor to investigate the effect of reaction temperature,operating pressure,and steam/carbon ratio on carbon conversion,reaction rate,methane concentration and its accumulated flow.The results showed that carbon conversion and reaction rate increased significantly with the increase of reaction temperature.Methane concentration and its accumulated flow were also increased,indicating that the methanation reaction was still under kinetic control in the range of 600 - 700 ℃.The enhancing of operating pressure led to the carbon conversion and reaction rate increased first and then decreased,while the methane concentration increased gradually,and its accumulated flow enhanced from 2.4 mL of normal pressure to 43.2 mL of 3.5 MPa.With the increase of steam/carbon ratio,carbon conversion and reaction rate rose significantly,while the methane concentration declined.The accumulated flow of methane showed a tendency of increase first and then decrease due to common influence of reaction rate and reaction equilibrium.