Experimental Study Of Biomass And Coal Co-carbonization

In this paper, three biomass such as pine sawdust, peanut shell and straw combinedwith the coking coal were carbonized in a fixed bed reactor and a semi-pilot coke ovenreactor. The effect of biomass on the yield and composition of co-carbonizationproducts were investigated. Meanwhile, the influence of adding asphalt on the quality ofcoke were also considered. The main conclusions were the following:Firstly, three different biomass combined with the coking coal were carbonized in afixed bed reactor. The experimental results indicated that the mass fraction of biomassincreased from0%to12%, the yield of char was reduced, while the yield of tar and gaswere improved. Moreover, there was a deviation between experimental and calculatedvalue of the co-carbonization product yield. Hence, it can be concluded that synergeticeffect was occurred during the co-carbonization process. When biomass was added intocoking coal, the percentage of CO and CO2in coke gas was improved, while the H2andCH4were decreased；The content of aromatic compounds and asphalt compounds in tarwere decreased, while the contents of aliphatic compounds and esters were increased,which indicated that biomass could contribute to produce low molecular weightcompounds. Thus, the quality of tar was improved.Secondly, the effect of biomass on the quality of coke was investigated in asemi-pilot coke oven reactor. The experimental results showed that there was a greatinfluence on the quality of coke by adding biomass to coking coal. The mass fraction ofbiomass increased from0%to12%, the index of crushing strength and CSR of the cokewere first increased and then decreased, while the index of CRI was first decreased andthen increased, the total porosity was increased; Compared with the original coking coal,when the mass fraction of biomass was3%, the quality of crushing strength and CSR ofthe coke were all improved except the abrasion resistance, when the mass fraction ofbiomass were more than3%, the quality of coke were decreased. The results showed that when the content of biomass in coking coal was in a low level, there was nosignificant impact on the quality of coke. There was a certain role in promoting thequality of coke when the asphalt was added to coking coal by mass fraction of3%，themost content of biomass can be increased to6%, and the quality of coke could meet therequirements of the national secondary metallurgical coke.Finally, the economic analysis of coking coal/biomass Co-carbonization wasconducted. As for the economic benefits, it could reduce the cost of coking; In case ofthe environmental benefits, it could reduce the emissions of dust, sulfur dioxide, carbondioxide, nitrogen oxides and other pollutants.