Study On The Particle Size Of The Powder Simi-Coke Prepared By Rapid Pyrolysis Of Low-Rank Coal

China's energy consumption will be dominated by coal for a long time,which will face severe sulfur dioxide emission reduction problems.At the same time,China is also a country with poor natural sulfur resources.Coal can not only be used as the raw material of fuel,but also raw material of adsorbent.The combination of its two properties is the best way to integrate the electric power production process with the flue gas purification process.For the first time,our group put forward a new complete technology process,which include in-situ preparation of amorphous powder adsorbent by coal combustion in power plant,rapid fluidization adsorption,coupling reduction of S02 by pyrolysis gas and carbon-based reductant,and synergistic control of other pollutants by exhausted coke and gas.In this process,in view of the high cost of traditional powdered activated coke preparation,Shandong University continued to propose and develop a one-step rapid pyrolysis of pulverized coal to prepare powdered activated coke,and carried out a systematic study,which confirmed the feasibility of this technology.However,previous studies mainly focused on the properties of activated coke in the preparation process of powdered activated coke,ignoring the particle size problem in the process.The change of coal particle size during pyrolysis has a great influence on its combustion and gasification properties.At the same time,the particle size of activated coke has some influence on its adsorption and regeneration performance.In the process of preparing low-rank coal activated coke,there exists crushing phenomenon,which leads to a significant reduction in the size of the obtained activated coke,seriously affecting the yield of the final expected size range.It is urgent to obtain data for related research.Therefore,the swelling characteristics in the rapid preparation of porous carbon materials from coal needs further studyIn view of the shortage of previous studies,the preparation system of powdered activated coke was improved to ensure the complete collection of activated coke.The effects of carbonization,activation and one-step process on the particle size of activated coke were studied step by step,and the effects of coking process parameters on the swelling behavior of activated coke were further studied.Finally,the influence of the particle size of activated coke on the properties of activated coke was studied by using the particle size classification after wide sieving coking.The study on the swelling behavior during the preparation of activated coke shows that during the carbonization process,the internal pressure of activated coke is produced due to the release of volatile matter,and the edge breakage occurs due to the lower strength of active coke skeleton.The average particle size of activated coke is smaller.During the activation process,the average particle size of activated coke is caused by the surface ablation of activated coke due to the reaction between activated gas and carbon on the particle surface.Reduce;in one-step process.Because the release of volatile matter from activated coke is accompanied by the formation of pore,the internal pressure of activated coke decreases,the breaking probability decreases,and the average particle size of activated coke decreases relative to raw coal,but is larger than that of carbonization before activation.The influence of coking process parameters on the particle size evolution of activated coke shows that the increase of coking temperature will increase the volatile release rate and thermal stress,promote the edge fragmentation of activated coke,and lead to the decrease of average particle size.Oxygen at low concentration will promote the volatile release and carbon ablation on the particle surface,resulting in the reduction of particle size of activated coke,and excessive ablation at high concentration will form macropore to promote volatile release.The particle size of activated coke increases with the decrease of breaking probability;the effect of carbon dioxide on the particle size evolution of activated coke is relatively small,hardly affecting the change of particle size;while water vapor inhibits the generation of volatile matter,it promotes ablation with the co-action of oxygen.With the increase of concentration,the particle size of activated coke decreases,but the decreasing range decreases.Finally,the study on the effect of the particle size of activated coke on the performance of activated coke shows that the particle size of activated coke has a great influence on the performance of activated coke.The results of simulating coking process with wide screening raw coal show that the size of activated coke collected is too small(0-58 um),some of the activated coke particles are agglomerated by debris,the proportion of micro-pore is small,and the desulfurization performance is not ideal;when the particle size level increases,the burning loss rate,graphitization degree,pore richness of activated coke decrease,and the sulfur adsorption capacity decreases greatly.Activated coke has the best desulfurization performance in the particle size range of 58-106 micron.In the actual preparation of activated coke,58-106 micron should be used as the expected collection particle size of activated coke.