Experimental Study Of Pyrolysis Process Of Zhundong Demineralized Coal

The global warming has becomingan increasingly serious isuue, CO2 emissions is main factor of this problem. A great amount of CO2 were let out especially from the burning of chemical fuel.China is a big country of CO2 emissions, the production process, especially in the field of CO2 from coal combustion has to be controlled.The OCCSS system is a new type of coal-oxygen/steam zero emission combustion systems,, requires demineralize coal as fuel. Therefore, this article studied the effect of DTF in demineralization of the pyrolysis process, and using nitrogen adsorption, Raman, XPS and other testing methods to study the pore structure, carbon skeleton structure, and variation of surface carbon functional groupsof the char.This article used Zhun-Dong coal as research object andmainly compared two pickling solutions:HCl/HF/HCl & HF/HNO3/HCl. Those two schemes can reduce the ash of ZD-raw and ZD-d to 0.2% and 0.09% respectively. HCl/HF/HCl fixed carbon has little effect on volatileand foundation carbonof coal.The addition of HNO3 in coal will have a greater damage to the coal. FTIR results showed that, the pickling process will remove a large number of inorganic elements in the coal,which will affect the pyrolysis process.At 1200℃ conditions, the release process of volatiles of ZD-raw coal and ZD-d coal at different residence time were compared, the results show that coal pyrolysis rate is faster than raw coal, but ultimately considerable degree of precipitation, which indicate that pre-pickling so that part of crosslinks were broken contribute pyrolysis, but the overall impact of volatile. A one step reaction model was used to calculate the ZD-raw and ZD-d pyrolysis kinetics parameters, ZD-raw activation energy E=18.53kJ/mol, pre-exponential factor ko=16.27s-1, the activation energy of ZD-d was E=58.88kJ/mol, pre-exponential factor ko=792.85s-1. It can be seen that demineralized coal has a higher pyrolysis activation energy, which means the removal of metal elements will affect the pyrolysis process.During pyrolysis process.The pore structure of the two coke are quite different, de-ash coal willhave fewer micro pores. With the residence time increased, ZD-d-char and ZD-raw-char coke surface of the graphite degree of increasing. Coal amorphous carbon content rare is also increased. XPS analysis showed that the C-C bond content of the coke surface increased significantly with the increase of residence time. In the pyrolysis process C-H, C-O and C=O are turn into a variety of H2, CH4, C2H6, HCN, H2 O and other volatile gases from the coal particles.