| The rapid pyrolysis and high temperature steam gasification of coal and petroleum coke were studied in a drop tube furnace in this paper. The gas products, changes of char structure and gasification reactivity during pyrolysis and gasification were investigated. The results show:The pyrolysis gas of three typical coals is mainly H2and CO, and increase as gasification temperature is raised with the temperature range of800-1400℃. The H2relative content order is anthracite>bituminous>lignite, whereas CO and CO2show the contrary. The pyrolysis gas of petroleum coke is mostly H2, and the pores of petroleum coke are mainly micro pores compared with coal. With the increase of rapid-heat-treatment temperature, the graphitization degree of coal and petroleum coke both get lower. The gasification reactivity of coal and petroleum coke chars are mostly influenced by the changes of their carbon crystallite structure.The composition ratio in gasification gas products of different coal chars is different, which the energy of gasification reaction with pure steam was supplied by electrical heating. The elevated temperature can significantly influence the gas composition ratio. As steam/coal ratio increased, the overall carbon conversion increases, while, relative contents of H2+CO decreases. The petroleum coke gasification gas products yields and conversion are relatively low, even the conversion is no more than10%as gasification temperature rises to1400℃. As gasification temperature increases, the char conversion is improved, and the pore surface area and pore volume of chars change continuously, average pore size is enlarged. In addition, the graphitization degree of char increases and gasification reactivity decreases as gasification temperature rises.Modified random pore model fits the char gasification curve very well. The char samples got at different conditions have different activation energy. |
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