Fundamental Research On Transformation And Utilization Of Co-pyrolysis Of Soybean Pod And Lignite

The effective use of resources is still a focus in contemporary economy and society.Non-renewable fossil fuels,especially coal,is still the dominant energy source in the development of China.The rough use of coal has led to inefficient utilization and serious environmental pollution.In the meantime,increasing energy demand has made renewable energy increasingly prominent.Therefore,the co-pyrolysis of biomass and coal can combine the renewable biomass resources and the clean and efficient use of coal,which not only makes full use of biomass resources but also reduces the amount of lignite and reduces the pressure on the environment.Low temperature co-pyrolysis of lignite(LI)and soybean pod(SP)was undertaken in a fixed bed reactor to investigate the influence of different soybean pod ratio(0%,10%,20%,30%,40%,50%,100%)in lignite on the effect of products in the study(GC-MS and FTIR were used to analyze the pyrolysis of tar,and FTIR,SEM and BET were applied to investigate structure of chars).The thermogravimetric analyzer was used to study the process of lost weight of co-pyrolysis and the effects of adding soybean pods on the pyrolysis process of lignite from the perspective of kinetics.The effect of Fe2O3 on the yield and quality of product from co-pyrolysis was analyzed.Finally,the co-pyrolysis of char was used to simulate the adsorption experiment of the water of printing and dyeing,results are as follows:(1)With the increase of soybean pod blending ratio,the yield of pyrolysis of char decreased gradually and yield of pyrolysis of gas increased,the pyrolysis of tar yield showed a tend of decrease after the first increase.The yield of pyrolysis of tar rised to11.98% with soybean pod ratio of 30%,which was reached the most-positive deviation to the theoretical values,indicating that the addition of soybean pod had a certain synergistic effect of co-pyrolysis to promote tar formation.(2)FTIR showed that the co-pyrolysis of tar had lower functional groups such as C=C and C=O compared with coal pyrolysis of tar,the addition of soybean pod could reduce the quantities offunctional groups,and it also could facilitates the breakage of oxygen-containing heterocycles and ether bond;GC-MS showed that compared with coal tar,the content of long-chain aliphatic hydrocarbons increased to 21.69% and that of aromatic compounds decreased to 23.34% and the content of phenolic compounds increased 6.4% than the theoretical value in co-pyrolysis of tar.(3)FTIR analysis showed that the content of oxygen-containing groups such as C=O and C-O increased in the co-pyrolysis of char;SEM showed that a large number of small fragments appeared on the char surface;BET showed that the specific surface area of the co-pyrolysis of char was larger than that of the coal char,and the addition of soybean pods can reduce the average pore size of theco-pyrolysis of char.(4)The addition of Fe2O3 slightly decreased the yield of tar and char,and the content of aromatics dropped to 20.39%.(5)The methylen blue removal rate of co-pyrolysis of char reach 80.68%.(6)The thermogravimetry showed that the temperature corresponding to the maximum lost weight rate of pyrolysis of blending(BL)decreased by 5.6? compared with the lignite alone pyrolysis.In addition,the termination temperature of volatile de-volatilization was brought forward of17.51?.The DTG value was higher than the theoretical value at 400 ?,the addition of soybean pod could improve the rate of lost weight of lignite.the co-pyrolysis process of lignite and soybean pods conformed to the first-order kinetics model.