Experiment Study On Properties Of Coal Gasification And The Migration Pattern Of Nitrogen

With the development of global economy, our demands for energy increases rapidly.Environmental pollution is becoming more and more serious. In China, coal is the mainenergy supply. Traditional use of coal is direct combustion. The efficiency is low andpollution is serious. So efficient and clean use of coal is gaining widespread attention.Large-scale coal gasification technology with high efficiency and low emissions is thefundamental measures to solve the China’s coal use problem.In this paper, pressurized thermal gravimetric analysis, elemental analysis, TriStar3000automatic adsorption instrument, GASMET FTIR Dx4000portable infrared gas analyzerand horizontal tube furnace are used to study pyrolysis and gasification processes of Fu Gucoal, Xiao Longtan coal, Sheng Li coal, cotton stalk and Jin Shan coke. The nitrogenmigration patterns of pyrolysis and gasification process are also discussed. Details andresults are as follows:Though pressurized thermal gravimetric analysis, the influence of pressure and coalrank on pyrolysis characteristic were studied. Non-isothermal integral method was used tocalculate the kinetic parameters.Possible synergies between Xiao Longtan coal and cottonstalk occurred. Activation energy of mixture decreases with the proportion of cotton stalkincreasing. As pressure increases, the weight loss value of coal increases first and thendecreases. The peak of weight loss moves to low temperature zone. Pressurized pyrolysispromotes the transformation of oxygen-containing functional groups. Activation energy ofhigh temperature is decreased with pressure increasing.In a horizontal tube furnace, pyrolysis properties of three coal samples were studied,the distribution of tri-state product and pore structure of coal char obtained at differenttemperatures were analyzed.BET surface area of Fu Gu and Xiao Longtan coal charincrease first and then decrease with temperature increasing. The BET surface area ofSheng Li coal char increases with temperature increasing.The nitrogen migration patterns of different coals during pyrolysis and gasification andthe influence of different minerals were studied in a horizontal tube furnace associated with the infrared gas analyzer. The results showed that nitrogenous gas released mainly in theform of NH₃and HCN during coal pyrolysis.However, NO is the dominant form in CO2atmosphere, and the release of HCN is limited.In steam atmosphere, NO is still the mainform.Moreover, the release of NO enhanced significantly. Coal through acid wash process,the release of HCN and NH₃reduce in pyrolysis. The impact of minerals on the release ofHCN and NH₃depends on different coals and minerals.Based on the release characteristics of CO, we propose a new coal CO2gasificationreactivity index expression,and seven kinds of different rank coals were used to verify thissuppose. Mixture gasification showed that gasification reactivity is improved significantlywith biomass adding.