Effect of pyrolysis conditions on the char surface area and pore distribution

Shenmu and Huating bituminous coals were devolatilized in a fixed-bed reactor and a drop tube furnace,to investigate the effect of heating rate and pyrolysis temperature on the surface area and pore distribution of chars.The heating rate in the fixed-bed reactor was 10 K/min and the maximum temperature was 900 ℃,while the heating rate in the drop tube furnace was higher than 1 000 K/s and the furnace temperatures were 1 100 ℃ and 1 500 ℃.The specific surface area and pore volume of chars were determined by N2 adsorption.The surface areas of rapid pyrolysis chars are much larger than those of slow pyrolysis chars,and decrease with increasing pyrolysis temperature.The experimental results show that the micro-pores are blocked with slow heating rate,and the proportion of meso-pore and macro-pore increase with increasing pyrolysis temperature.