关键词: 移动床, 热解, 传热, 传质, 内构件, 焦油品质, 调控

Abstract: The pyrolysis characteristics of Naomaohu coal were studied in a moving bed reactor with internals consisting of multi-stage baffles and multi-stage gas outlet lines, and compared with the coal pyrolysis behavior in conventional fixed bed reactor. The effects of heat transfer rate and pyrolysis temperature on products yield, pyrolysis gas composition, tar composition and quality were investigated in the two reactors. The results showed that the heating time of coal particles in the moving bed with internals is shortened by more than 60% than that of the fixed bed during pyrolysis at 450℃, and the internals can significantly enhanced the heat transfer rate of the particles in reactor. With increasing the pyrolysis temperature, the ratio of C2H4 / C2H6 and C3H6 / C3H8 in pyrolysis gas increased, the secondary reaction of volatiles increased, but the degree of cracking is lower than that of fixed bed. The tar yield in the moving bed with internals increased first and then decreased with increasing temperature, reached a maximum of 10.8 wt.% at 550℃, which was about 28.6% higher than that of the fixed bed. When the pyrolysis temperature is higher, the content of asphaltene components in the tar produced by the moving bed is lower. At 750℃, the content of light components in tar reached 85.17%, and the content of aliphatic hydrocarbons decreased to 28.00 area%. Compared with the fixed bed, the role of internals (multi-stage baffles and gas outlet lines) in regulating the pyrolysis reaction of Naomaohu coal and improving the yield and quality of pyrolysis tar are revealed.

Key words: moving bed, pyrolysis, heat transfer, mass transfer, internals, tar quality, regulation