Study On Gasification Briquette From Low Rank Bituminous Coal

Bituminous coal in low rank makes up a big percentage of coal reserves in China, which is of high quality and widely distributes. Owing to eliminating formation pressure, great elastic expansion appearing in coal briquette by bituminous coal in low rank leads to breakage of coal briquette again. In light of this situation, the technology of briquette of bituminous coal in low rank is still in the initial stage. To do technological research on briquette of bituminous coal in low rank will has important theoretical significance and widely implicational value. Supported by special fund on"Research on atmospheric fixed-bed gasification technology and applicability of raw coal (No. 120913)". Lots of tests (including industrial test in situ) were carried out to do systematic study on briquette of bituminous coal in low rank. Main achievements are as follows:(1) Research from micro and macro perspective shows that bentonite is more suitable for cold binder of bituminous coal in low rank than odium silicate and red mud; On condition that the ration of major coal and blending coal is constant, the strength of coal briquette is in increase with the ration of bentonite, and increases firstly and decreases then with the formation pressure, and region near 20kN is the optimum pressure. On the basis of bentonite as a cold binder, sodium humate can be chosen as thermal binder;(2) Through test of macroscopic mechanical strength and microstructure analysis by electron microscopy, It is obtained that asphalt chosen as the additional binder of bituminous coal in low rank gets better effect than fat coal. Asphalt particle size has obvious effect on mechanical strength. Smaller or excessive particle size are detrimental to improve thermal strength, Distribution of particle size between 0.5 ~ 1.5 millimeter is best;(3) Appraised by briquette's cold strength, thermal strength and re-dry strength, the results of variance analysis and visual analysis by orthogonal test show that reasonable ratio of mixed materials is 8%(bentonite), 2%(sodium humate), 5%(asphalt) and 85%(Ration of bituminous coal in low rank and bituminous coal in medium-high rank is 2:1). Further tests show that coal briquette has excellent water-resistance and good thermostability under this ratio.(4) Testing results show that 160℃can be used as the best terminal temperature for drying coal briquette by bituminous coal in low rank (shenmu coal), and reasonable holding time of best terminal temperature is 20 ~ 30min. Developed formula aiming at shenmu bituminous coal in low rank is fully applicable for Yima long flame coal;(5) Industrial test is implemented rely on No. 120913 to illustrate that cold strength, thermal strength and completely reactivity of coal briquette by bituminous coal in low rank qualify the need of atmospheric fixed-bed gasification furnace by national and industrial standard, meantime, the calorific value of gas also meet requirement. Gas composition, ash layer and amount of removal dust by cyclone separator are basically like before.