Experimental Study On The Coal Char Porous Structure Of Fast Pyrolysis In An Entrained-Flow Reactor

In this paper, the configration and setting-up process of the Entrained-Flow reactor has been introduced. The purpose and setting-up process of the coal particle feeder has been described. the step motor and the control program of the step motor with PLC, has been introduced too. Char sample made from bituminous coal from Shijingshan Thermal Power Plant at different pyrolysis temperatures and different pyrolysis times in the Entrained-Flow reactor, under the condition of fast pyrolysis. Absorption isotherm of nitrogen at low temperature is gotten by using AUTOSORB-1-C auto-absorption analyzer from Quantachiome Company. After analysis of absorption isotherm, calculation of pore structure parameters, such as specific area and pores volume, and fractal analysis of char surface structure, pore structure of char are presented, which provides foundation for further research on reaction process and characteristic of coal and char.Analysis of coal and char shows that under reducing atmosphere, char specific area, pore volume decrease at the initial stage and increase later on with the increase of pyrolysis time, and to the maximum at about 550 milliseconds. at the temperature of 1250, 1300 and 1350℃. While char specific area, pore volume increase at the initial stage and decrease later on at the temperature of 1200. The range of char specific area increase faster than it's pore volume with the increase of pyrolysis time. Char fractal dimension increase with the increase of pyrolysis time, and reactivity is enhanced. The char specific area and pore volume under the fast pyrolysis bahaves differently from the slower pyrolysis. char specific area and pore volume at 1250℃are higher than those that are at other temperatures. Char fractal dimension at 1350℃are larger a little than those at other temperatures , indicating that the higher the temperature is , the better the pore characteristic and reactivity are.