Study On Pyrolysis Performance Of Deashing Oil Shale And Coal Blending Coking

Huadian oil shale(HDOS)was deashed using hydrochloric acid,hydrofluoric acid,and nitric acid.The deashed oil shale(HDSX)was pyrolyzed in a fixed-bed reactor at the temperatures of 300,350,400,450,and 500^oC.The treated samples were characterized by caking index(G),proximate analysis,utimate analysis,Fourier transform infrared spectrometry(FT-IR),Raman,solid nuclear magnetic resonance(¹³CNMR),and TG-DTG to study the changes in structural properties and kinetic parameters.HDSX pyrolyzed at400^oC(HDSX-400)was selected to replace Qinglongshan lean coal for coal-blending-coking because of its highest G parameters.Two types of cokes were prepared from initial scheme of coal blends(Qingting fat coal,Huainan 1/3 coking coal,Qinglongshan lean coal,and Australian coking coal)and substituted scheme of coal blends,i.e.,HDSX-400(5 wt%)repaled the equivalent amount of Qinglongshan lean coal,respectively.The reactivity,coke strength after reaction(CSR),micro strength((MSI^0.2)),TG-DTG,and BET of the two types of cokes were analyzed.The results showed that:(1)After deashing,the ash content of HDOS decreased by 61.55%and the ash content of HDSX was 5.31%.(2)The G parameter of HDSX-400 was the highest among all the samples.The experimental results of ¹³CNMR showed that when the temperature increased up to 400^oC,the total content of fat carbon decreased from 0.723 to 0.397,while the total content of aromatic carbon also increased from 0.229 to 0.457,indicating that the fat carbon gradually decomposed with increasing temperature.(3)The KAS method was used to analyze the samples.Based on pyrolysis kinetics analysis,the average activation energy of HDSX-400 among the seven samples was the highest.The value was 358.613 KJ/mol.Most of the correlation coefficient of linear fitting was above 0.900.With the increase in pyrolysis temperature,the activation energy of the samples increased,indicating that the reactivity of the samples decreased.(4)CO₂reactivity of the two types of cokes were 50.8%and 52.2%respectively,coke strength after reaction(CSR)were 43.9%and 45.3%,respectively,and the MSI^0.2were 49.0%and 38.0%respectively.The specific surface areas of the two kinds of cokes were 6.7663 m²·g^-1and 4.8993 m²·g^-1,respectively,and the pore volumes were 0.002894mL·g^-1and 0.001587 mL·g^-1,respectively,indicating that the performance indexes of coke structure under the two coal blending schemes were close to each other.