煤焦催化气化活性位扩展模型的研究
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摘要: 针对煤催化气化反应中传统的煤气化动力学模型不再适用或应用范围受到限制的现实，从催化作用机理分析入手，以煤焦CO2催化气化为研究对象，建立了描述气化反应速率与转化率关系的动力学模型——活性位扩展模型。并以KCl催化剂及K-Ni(10%Ni)复合催化剂作用下神府煤焦CO2气化的实验结果对模型进行验证。结果表明，活性位扩展模型很好地体现了煤焦催化气化的动力学规律，即催化剂的添加，有效地增大了反应界面处的活性部位和活性表面积，使气化反应在更温和的条件下快速进行；模拟值与实验值吻合较好，最大偏差10%。由于反应初期的传质阻力不可忽略，实验值与模拟值存在一定误差。Abstract: Based on the widely accepted catalysis mechanism and the reasonable assumptions, a new kinetics model, active site extending model was developed to describe the catalytic coal char gasification rate more properly. The model was validated with the experimental results of CO2 catalytic gasification of Shenfu coal char at various temperatures by using KCl and K-Ni compound catalysts, and the model parameters for Shenfu coal char gasification were obtained. The kinetic behaviour and catalytic mechanism are well explained by active site extending model. The maximum error between the simulated and experimental results is about 10%. It is also revealed that the catalysts can effectively improve the gasification rate and reduce the gasification temperature by increasing the active surface area and sites. A slight disagreement between the simulated and experimental results can be attributed to the mass transfer resistance during the initial reaction stage.
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Key words:
- coal char catalytic gasification /
- active site /
- kinetic model
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