Effect Of Inherent Moisture On Coal Pyrolysis And Gasification Characteristics

As the key to coal conversion and the core of clean and efficient utilization of coal,coal pyrolysis and coal gasification technology has received widespread attention from researchers.Majiata bituminous coal and Indonesian lignite were used as raw materials,and fixed-bed was used to study the effects of coal’s inherent moisture,pyrolysis temperature,and coal particle size on the yield of coal pyrolysis gases（H₂,CH₄,CO,CO₂）in the dissertation;thermogravimetric analyzer was used to study the effects of coal moisture,pyrolysis temperature and coal particle size on the carbon conversion rate and reaction activity of CO₂gasification of coal char;FT-IR was used to analyze the effects of inherent moisture and other factors on the peak intensity of functional groups on the surface of coal char;the kinetics of CO₂gasification of coal char was solved by using homogeneous model and shrinking core model.Research indicates:（1）The inherent moisture of coal is able to change the distribution of coal pyrolysis gas,increase the H₂production rate significantly,and promote CO production at a pyrolysis temperature higher than 950°C.The yields of H₂and CO produced by coal pyrolysis shows an upward trend with the increase of pyrolysis temperature.At 950°C,as the coal particle size decreases from 0.5 to 1.0 mm to 0.2 to0.5 mm,the yields of H₂,CH₄,CO,and CO₂from the pyrolysis of the two coals are increased.（2）With the loss of inherent moisture,the CO₂gasification activity of coal char produced by coal pyrolysis increases.With the increase of the pyrolysis temperature,the CO₂gasification activity of coal char produced by the pyrolysis of dry coal decreases.With the decrease of coal particle size,the CO₂gasification activity of coal char produced by pyrolysis of Majiata bituminous coal containing inherent moisture increases,and the CO₂gasification activity of coal char produced by pyrolysis of dry Majiata bituminous coal decreases,and whether Indonesian lignite contains inherent moisture or not,the CO₂gasification activity of coal char produced by its pyrolysis is increased.（3）After losing inherent moisture,the intensity of-OH peak,C-H peak of alkanes and C-O peak of alcohol/phenol/ether of Majiata bituminous coal at 700～800°C decreases,and the intensity of aromatic C-H peak increases at 900～1000°C;the carbonyl C=O and alcohol/phenol/ether C-O peak intensity of Indonesian lignite char increased,and the aromatic C-H peak intensity increased at 1000°C.With the increase of the pyrolysis temperature,the aliphatic ether peak intensity of the coal char produced by the pyrolysis of Indonesian lignite containing inherent moisture increases,and the alkane C-H peak intensity first increases and then decreases;the aliphatic ether peak intensity of the coal char produced by the pyrolysis of the Majiata bituminous coal containing inherent moisture first increases and then decreases.The particle size also has some effects on the peak intensity of the surface functional groups of the coal char.（4）With the loss of inherent moisture,the activation energy of CO₂gasification reaction of coal char produced by coal pyrolysis decreases.With the increase of pyrolysis temperature,the activation energy of CO₂gasification reaction of coal char increases.With the decrease of coal particle size,the activation energy of CO₂gasification reaction of coal char produced by pyrolysis of Majiata bituminous coal containing inherent moisture decreases,and the activation energy of CO₂gasification reaction of coal char produced by pyrolysis of dry Majiata bituminous coal increases,and whether Indonesian lignite contains inherent moisture or not,the activation energy of CO₂gasification reaction of coal char produced by its pyrolysis is decreased.