Experimental Study On Preparation Of Semi-coke By Briquetting Shenmu Fine Coal

In the process of producing semi-coke from Shenmu Hengyuan Coal Chemical Co.,Ltd.Tthere are some problems in the process,including excess small-sized raw materials,high price of Shenmu lump coal,and difficulty in handling liquefied residue.To deal with these problems,the preparation of semi-coke from Shenmu fine coal was studied.The effects of coal blending type,molding pressure,type and proportion of binder and liquefaction residue on briquetting performance were studied.Cold compressive strength（SCC）,thermal strength（BTS）,thermal stability(BTS₊₁₃)and drop strength（DS）,were used as indicators to characterize the preparation process.Using the briquette prepared from Shenmu fine coal at the optimal process parameters as the raw material for the preparation of semi-coke,the effect of the dry distillation process on the properties of semi-coke was studied,and the compressive strength,ash,volatile matter residual rate and fixed carbon of semi-coke were studied.The content and total sulfur are used to characterize the performance of semi-coke and the low temperature dry distillation test of Shenmu fine coal,coking coal,liquefaction residue and briquette.And thermogravimetric analysis of Shenmu coal and briquette.The main conclusions of the study are as follows:1.Shenmu fine coal is non-cohesive coal.Because of the coal quality,the preparation of briquette by using Shenmu fine coal single coal as raw material can not obtain briquette with excellent performance;Shenmu fine coal forming experiment is respectively matched gas-fat coal,coking coal,and liquefied residue can all promote the preparation of briquette from Shenmu fine coal;the coal is made from Shenmu fine coal as the main raw material,and the liquefied residue is used as the ingredient.The briquette prepared by coking coal is stronger than the gas-fat coal.Through the single factor experimental research on the formation of Shenmu fine coal,Shenmu fine coal is the main raw material,and the proportion of coking coal as coal blending is less than20%,the proportion of liquefaction residue is less than 20%;the molding pressure is small.The gap between the particles of the mixture is large,resulting in low strength of the briquette;if the molding pressure is too large,crushing will occur,and a new section will appear inside,which will also lead to a decrease in the strength of the briquette.The optimum actual molding pressure is 68 MPa..2.The addition of cement in Shenmu fine coal can improve the briquette SCC,but studies on single binders such as sodium silicate,bentonite,sodium humate,carboxymethyl starch,pregelatinized starch and binders are shown.In the process of molding the Shenmu fine coal,the organic binder can promote the briquette prepared by the formation of the final coal,and select a polymer liquid composite binder as the binder for the formation of Shenmu fine coal,combined with the production cost and performance requirements.The proportion of the binder added was 5%,the briquette SCC was 638.3 N/piece,and the BTS was 558.2 N/piece.3.Through orthogonal experimental design,it is found that different factors have significant influence on the briquette index prepared by Shenmu fine coal formation.The comprehensive balance method is combined with the industrial requirements for analysis.The final optimization scheme is:the main raw coal of Shenmu fine coal.The proportions of coking coal and liquefied residue in the state of Shenmu fine coal,coking coal and liquefaction residue are 73.8%,5.4%,20.8%,respectively,combined with the molding pressure conversion coefficient of 1.89,the actual molding pressure is 68 MPa,Shenmu fine coal forming preparation type The indicators of coal are relatively good.This scheme was used to prepare the briquette from Shenmu fine coal.After testing,SCC,BTS,BTS₊₁₃ and DS were 553.4 N/piece,587.4 N/piece,94.1%and 81.3%,respectively.4.In the study of the influence of the dry distillation process on the performance of semi-coke,it is found that the compressive strength of semi-coke increases with the increase of dry distillation temperature,heating rate and holding time,and the dry distillation temperature is the compressive strength of semi-coke.The influence of the dry distillation temperature and the heating rate is obvious.In the effect of the dry distillation process on the ash,volatile matter and fixed carbon of the semi-coke,the ash and fixed carbon of the semi-coke prepared by the Shenmu fine coal formation increase gradually with the increase of the dry distillation temperature and the residual rate of volatiles tends to decrease gradually.The effect of holding time and heating rate on the ash content,volatile matter residual rate and fixed carbon of semi-coke is not obvious;the dry distillation process has an effect on the total sulfur content of semi-coke.The dry distillation temperature,heating rate and holding time will reduce the total sulfur content in the briquette,but the dry distillation process shows no obvious rule for the change of total sulfur content.In combination with the performance requirements of semi-coke and energy consumption,the analysis considers that the semi-coke has a dry distillation temperature of 600°C,a heating rate of 5°C/min,a holding time of 30-45 minutes,and a compressive compressive strength of 400 N/piece.The ash is between 9.30%and 9.46%,the volatile content is between 8.12%and10.64%,and the fixed carbon content is between 89.36%and 18.88%,which basically meets the technical specifications of semi-coke.5.The thermogravimetric analysis of Shenmu fine coal showed that Shenmu fine coal had the highest weight loss rate at 440°C.The weight loss law of briquette at different heating rates is significantly different.Under the condition that the sample reaches the same weight loss rate,the temperature of retorting is higher.At the same retorting temperature,the higher the heating rate,the sample is in the process of retorting.The faster the volatilization analysis is,the larger the precipitation and the more complete the pyrolysis.