Experimental Study On Combustion And Explosion Characteristics Of Huolinhe Lignite And Semi-coking Dust

Coal dust explosion accident is the main problem affecting coal mine safety production.The main gas factor of coal dust combustion and explosion reaction is early pyrolysis products.So early in the coal dust explosion,this paper pyrolysis products affect the coal dust explosion characteristics of the basic problems,the experimental study and theoretical analysis,the method of combining Huolinhe lignite was studied explosion early pyrolysis stage of different activated semi-coking particles of dust explosion characteristics,and reveal its thermal reaction mechanism.The main research results are as follows:（1）X-ray photoelectron spectroscopy（XPS）,FTIR and other analytical detection techniques were used to identify the chemical tructure of Huolinhe lignite.The results showed that the carbon in lignite is mainly aromatic structure and its substituted alkanes,and the oxygen is mainly ether oxygens,carbonyl groups and carboxyl groups.The active group structure is mainly tri-tetrasubstituted on the benzene ring,while the oxygen-containing functional groups are mainly hydroxybenzene,ether,and aromatic benzene.There are only three kinds of structures in the hydroxyl functional group:cyclic hydrogen bond,OH┅OH hydrogen bond formed by self-associated hydroxyl group,and the OH┅πhydrogen bond formed byπon the aromatic ring.（2）A programmed heating device was used to simulate the pyrolysis reaction process at the early stage of the explosion of Huolinhe lignite to prepare semi-coking dust particles with different active organic functional group structures.A simultaneous differential therma analyzer was used to study the pyrolysis characteristics and combustion characteristics of Huolinhe lignite and semi-coking dust particles.The results show that as the semi-coking dust particles approach the later stage of pyrolysis,their ignitability and comprehensive combustion characteristic index decrease,and the analysis of apparent activation energy,combustion reaction difficulty and residual volatilization during combustion increases.（3）Dust explosion sensitivity experiment was conducted to study and analyze the factors influencing the explosion sensitivity of Huolinhe lignite and semi-coking dust.The results show that the dust is less likely to be ignited with the increase of final pyrolysis temperature.The dust in the stacked state is more likely to accumulate heat during the heating process than when the cloud-1ike dust is ignited,resulting in a 1ower ignition temperature.When CO₂ is no longer precipitated from the semi-coke dust particles at the late stage of pyrolysis,the lower explosive mass concentration decreases and the explosive sensitivity increases.（4）The explosive characteristics of huolinhe lignite and semi-coking dust and their changing rules were studied by the experiment of dust cloud explosive intensity characteristics.The results show that semi-coking dust is still explosive;at the same time,the content of volatile matter in the dust can promote its combustion and explosion rate.The flame length as well as the reaction rate of semi-coke dust particles in the late stage of pyrolysis reaction were obviously reduced.The volatile fraction content was positively correlated with the flame length,while the fixed carbon content was negatively correlated with the flame length by the principal factor analysis method.（5）The thermodynamic characteristics of huolinhe lignite dust were studied by thermal analysis dynamics theory,and the reaction mechanism during heating was revealed.The initial heating time was introduced to modify the volume model of coke during gas-solid heterogeneous combustion.The coats-Redfern method was used to solve the reaction mechanism function of Huolinhe lignite at different pyrolysis stages,and the results showed that the diffusion mechanism of Huolinhe lignite during heating was more consistent with the three-dimensional spherically symmetric model.The research results have important theoretical value and practical significance for studying the effect of the physicochemical characteristics of the semi-coke dust on the explosion characteristics of the Huolinhe lignite in the initial pyrolysis stage,and revealing the reaction mechanism of the Huolinhe lignite when heated.At the same time,it provides new ideas for studying the mechanism of coal dust explosion and the development of explosion suppression technology.There are 76 pictures,33 tables and 154 references in this paper.