中国典型煤种煤焦水蒸气气化反应特性研究

Experimental study on gasification characteristics of Chinese typical high ash fusion temperature coal with steam

研究了5种典型煤种在1 100-1 400℃范围内的煤焦-水蒸气气化反应特性,并利用未反应碳缩合模型进行数值模拟.实验与计算结果表明,在煤焦-水蒸气气化反应过程中,随着温度的升高,气化反应控制步骤逐渐由化学反应动力学控制过渡到扩散控制;在高温条件下,高灰熔点煤与低灰熔点煤的气化反应特性有所不同,这与高温下低灰熔点煤灰发生熔融、灰层阻力增大有关.未反应碳缩核模型的计算值与实验值吻合较好.

The characteristics of char-H2O gasification and its numerical simulation were studied by using TGA-51H in high temperature range（1 100-1 400℃ ）. The experimental and simulation results show that the control step of coal char-H2O gasification reaction transits from chemical reaction control at low temperature to pore diffusion control at high temperature with the increasing of temperature. The gasification characteristic of low ash fusion temperature coal in high temperature is different from that of high ash fusion temperature coal. The ash fusion behavior is likely the main factor accounting for this phenomenon. The unreacted-core shrinking model can show well effect of temperature, pressure, gas film diffusion, ash film diffusion and surface reaction on coal char-H2O gasification reaction rate.