Study On Multi-field Coupled Catalysis And Application Of Inherent Minerals In The Microwave Pyrolysis Process Of Ningdong Coal

Energy is the foundation and driving force for the progress of human civilization,is vital to the national economy,people's livelihood and national security,and is essential for promoting economic and social development and enhancing people's well-being.Ningdong Coalfield has abundant reserves,and there are considerable reserves of long-flame coal with a relatively low degree of coalification.Long flame coal has the shortcomings of low calorific value,low efficiency of direct combustion,and large pollution to the environment.Therefore,the research and development of high-efficiency,low-consumption,pollution-free coal pyrolysis process has become a hot technology and important for the efficient and clean utilization of Ningdong coal.Direction of development.The combination of microwave heating and coal pyrolysis technology is a hot topic for efficient and clean utilization of low-rank coal.In the process of microwave pyrolysis of coal,the physicochemical properties of coal,inherent mineral composition,microwave field,temperature field and other variables are interactively coupled to affect the progress of the catalytic pyrolysis reaction.In this paper,from the perspective of the interaction and coupling of the microwave field,temperature field and coal's intrinsic minerals,the basic research on the product yield and composition characteristics of Ningdong coal microwave pyrolysis process is carried out.Through industrial analysis and characterization by SEM,FTIR,XRD,TG-FTIR and other methods,the structural characteristics and properties of four coal samples from Hongliu,Lingxin,Meihuajing and Yangchangwan in Ningdong mining area were analyzed.The four coal samples are all low-rank coals with a low degree of aromatization and low coalification.The main inherent mineral components are kaolinite,quartz,calcite and pyrite.Characterization and analysis of the temperature change of microwave pyrolysis of Ningdong coal and the yield and composition of gas,liquid,and solid three-phase products by FTIR,GC-MS,infrared thermal imager and other methods,to study the inherent minerals and properties of microwave pyrolysis of Ningdong coal Microwave field,temperature field and other multi-field coupling synergistic formation mechanism.Experiments show that compared with the raw coal sample,the temperature of deashed coal in the microwave field becomes slower,the final pyrolysis temperature decreases,and the pyrolysis gas yield and tar yield decrease.Through industrial analysis and ICP-AES characterization,it is found that the inherent mineral influence of Ningdong coal is the main cause.Because the iron-containing minerals of the raw coal sample have a transition bond type,the dielectric loss factor?''is relatively large.The microwave energy is quickly converted into heat energy,resulting in a local"hot spot"phenomenon,which promotes the increase of the temperature of the raw coal sample,and at the same time contains iron.The Fe in minerals can provide the ability to receive electrons.The empty 3d orbitals make the?bonds of the unsaturated hydrocarbons in the coal and the oxygen-containing functional groups combine to realize the enhancement of chemical adsorption and the cracking reaction of the organic structure in the coal to generate more small molecules.Substance to increase the yield of pyrolysis gas.Based on the basic research on the application of multi-field coupling synergy of the inherentl minerals of Ningdong coal under microwave pyrolysis conditions,a microwave pyrolysis catalytic system suitable for Ningdong coal was constructed,and the ratio of active components in the catalyst was adjusted to improve the microwave pyrolysis of Ningdong coal.Pyrolysis gas and liquid two-phase product yield and increase its effective components H₂,CO and light tar content.The iron-based and semi-coke-based Fe-Ni composite catalyst prepared by the impregnation method was used for microwave pyrolysis of Ningdong coal.The results show that the iron-based catalyst has a better effect on the yield and distribution of gaseous products from the microwave pyrolysis of Ningdong coal.The influence of liquid phase products,especially the improvement of the degree of tar lightening,is relatively poor.The semi-coke-based Fe-Ni composite catalyst can improve the yield of Ningdong coal microwave pyrolysis gaseous products and the content of effective components,and at the same time,the effect of lightening tar is more excellent.The content of light components has increased by 51.7%.Microwave pyrolysis of Ningdong coal to produce space oil raw materials provides a reference basis.