煤焦催化气化中非均相反应动力学的研究

Study of Heterogeneous Reaction Kinetics in Catalytic Coal Gasification

以神木煤焦为研究对象,在小型加压固定床上考察了不同气化剂(水蒸气、二氧化碳、氢气)、催化剂负载量、水蒸气分压、氢气分压和一氧化碳分压对碳转化率和气化反应速率的影响。结果表明,对于非均相的催化气化反应来说,反应速率顺序为C-H2O>C-CO2>C-H2。H2和CO不同程度地抑制煤焦水蒸气气化反应,CO的抑制作用明显大于H2。在700℃,当添加5%的CO,碳转化率降低约50%。基于Langmuir-Hinshelwood(L-H)方程,结合随机孔模型,同时考虑催化剂负载量及气化产物分压的影响,建立了煤焦催化水蒸气气化动力学模型,模型预测反应速率常数与实验值误差在10%以内,说明建立的动力学模型可以较好地模拟煤焦的催化水蒸气气化反应过程。

Gasification of Shenmu coal char have been carried out in a pressured fixed bed reactor to investigate the effect of gasification agents （H20, CO2, H2）, catalyst loading, and partial pressure of hydrogen and carbon monoxide on the carbon conversion and reaction rate. Results show that the order of rate for heterogeneous reactions is： C--H2O 〉C-CO2〉C-H2. H2 and CO inhibit the steam gasification to some extent. The inhibition by CO is much greater than that of H2.Carbon conversion decreases by about 50% with the addition of only 5%CO at 700 ~C.A kinetic model is developed combined Langmuir-Hinshelwood （L--H） with the random pore model, considering the effect of catalyst loading and the partial pressure of gasification product. The deviation between predication and experiment vale is less than 10%, indicating that the derived kinetic model is appropriate for describing catalytic steam coal gasification.