Analysis On The Pyrolysis Of Lignite In Different Regions Of My Country And The Effect Of Iron On The Pyrolysis Of Lignite

With the rapid growth of energy utilization,lignite,a young coal resource,is gradually moving toward an increasingly important position.my country’s lignite is mainly distributed in Xinjiang,Yunnan,and the central and eastern regions of Inner Mongolia.Understanding the physical and chemical properties of these lignite has important practical significance for the efficient use of low-rank coal.In this paper,six types of lignite from different regions of my country are selected,and the lignite is slowly and gently pyrolyzed under the conditions of a programmed temperature of4℃/min and a final temperature of 900℃.And through elemental analysis,industrial analysis,thermogravimetry,online gas chromatography,XRD,FTIR and other related instruments to characterize it to explore the characteristics of the physical and chemical properties of lignite in different regions.In the later stage,three representative lignites were selected to explore the effect of iron-donating minerals on the pyrolysis behavior of lignite by means of iron-donating salts.First of all,the basic characterization of elemental analysis and industrial analysis of six types of lignite coal.Elemental analysis shows that Xinjiang lignite contains more impurities,and the carbon content is significantly lower than that of the other five types of lignite.In addition,the H/C value of Yunnan Xiaolongtan lignite is the highest through calculation,indicating that its aliphatic content is more abundant than other lignite.Industrial analysis can also see the characteristics of the lowest fixed carbon content of Xinjiang lignite.In addition,the characteristics of the highest volatile content of Yunnan Xiaolongtan lignite are also obtained from industrial analysis,which also illustrates the rich aliphatic characteristics of Xiaolongtan lignite.In addition,the structural parameters obtained through the fitting calculation of the lignite infrared characterization also show that the Yunnan Xiaolongtan lignite is rich in aliphatic groups,and the Xinjiang lignite coal has the characteristics of low metamorphism,low rank and relatively young lignite.Through the online gas chromatographic device（programmed to 900℃,heating rate 4℃/min）to examine the difference in the release of pyrolysis gas and the release temperature,it can be obtained that the Xiaolongtan lignite has the highest thermal interpretation of methane gas,indicating its aliphatic The most abundant content.Secondly,six types of lignite were demineralized step by step through pickling treatment.On-line gas chromatography pyrolysis showed that Xinjiang lignite was significantly improved after pre-acid treatment.Too much impurity content in Xinjiang lignite causes pyrolysis gas generation after demineralization to be inconsistent with other lignite.（There will be no further discussion on Xinjiang lignite in the later period）.Thermogravimetric analysis shows that inherent minerals play a role in promoting the pyrolysis behavior of lignite.In addition,the inherent minerals have an obvious promotion effect on the generation of H₂from lignite pyrolysis gas.Finally,by selecting Hulunbeier,Xiaolongtan,Shengli lignite and carrying out the method of adding iron salt（the mass of iron element is 5%of the mass of the coal sample）,the pyrolysis behavior of the iron added catalyst was investigated.The results showed that:through thermogravimetric characterization It can be seen that the thermal weight loss rate of lignite after iron attachment has increased significantly,and the thermal weight loss rate has decreased significantly.On-line gas chromatography showed that:1.The generation rate of CO pyrolysis gas after iron attachment was significantly lower than that of hydrochloric acid coal washing,indicating that iron minerals have the effect of inhibiting the generation of CO gas from lignite.2.The methane pyrolysis gas of lignite with iron is significantly lower than that of lignite coal washed with hydrochloric acid.3.After adding Fe Cl₃salt,the rate of H₂generation in the early stage is higher than that of hydrochloric acid washed lignite,indicating that the release temperature of lignite H₂after iron is advanced,and the iron lignite can promote the release of lignite H₂.