单颗粒煤粉热解时焦油的二次反应和扩散
Secondary reactions and diffusion of tar during single coal particle pyrolysis

建立了数学模型来研究单颗粒煤粉热解时焦油的生成规律。该模型基于碎片化与扩散(FD)煤热解模型, 考虑了一次气体产物在颗粒内部的二次反应和扩散, 用沉降炉热解实验验证了模型的正确性。用该模型研究了热解终温、加热速率和颗粒粒径对杨村煤热解时焦油生成的影响。结果表明: 二次反应和扩散之间的竞争对焦油的生成有很大影响。热解终温和加热速率的上升会促进焦油的二次反应和扩散, 对二次反应的促进作用更强。颗粒粒径的增大会促进二次反应, 阻碍扩散, 因此对二者之间的竞争影响更大。热解终温的上升、加热速率的上升和颗粒粒径的增大都会降低最终的焦油产率。
Abstract：A numerical model was developed to investigate the tar production during pyrolysis of a single coal particle. The model was based on the fragmentation and diffusion (FD) coal pyrolysis model and considered the secondary reactions and diffusion inside the coal particle. The model was validated by pyrolysis experiments in a drop-tube furnace and then used to investigate the influences of the final temperature, heating rate and particle diameter. The results show that the competition between the secondary reactions and tar diffusion greatly influences the tar production. Increases of the final temperature and the heating rate improve both the tar secondary reactions and the diffusion while increasing the particle diameter improves the tar secondary reactions and hinders the diffusion. The final tar yield decreases with increasing final temperature, increasing heating rate and increasing particle diameter.