Study On Organic Matter Structure Of Oil Shale And Its Co-pyrolysis Performance With Coal

In this thesis,Huadian oil shale?HDOS?,Shenhuo lean coal?SM?were used as the samples.HDOS was demineralized using acid.HDOS,demineralized oil shale?HDSX?,SM,and the mixures?MS1 and MS2?obtained by mixing in different proportions of HDSX with SM were heated at different temperatures?300 centigrade,350 centigrade,400 centigrade,and 450 centigrade?,and the samples were analyzed by scanning electron microscope?SEM?,Brunner-Emmet-Teller?BET?measurements,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,Fourier transform infrared spectroscopy?FT-IR?,thermogravimetry?TG?and electron paramagnetic resonanc?EPR?.The effects of different temperatures on surface morphology,pore structure,functional group,pyrolysis kinetics,and free radical concentration were studied.The results showed that:?1?The contents of aromatic carbons and aliphatic carbons in HDOS were 0.054 and 0.92,respectively.After demineralization,the contents were 0.13 aand 0.89,respectively.It shows that demineralization has little effect on carbon type in oil shale organic matter.?2?After heat treatment at different temperatures,the specific surface area?SSA?of HDOS increased.For HDSX and SM,their SSAs decreased.As to MS1,its SSA increased first and then decreased.The carbon element on the surface of HDOS,HDSX,SM and the mixed samples mainly existed in the forms of C-C and C-O.In the temperature range of 300-350?,with increasing heating temperature,the free radical contents of HDOS increased from 4.36×10¹⁷sping·g^-1 to 3.00×10¹⁹sping·g^-1,and the free radical contents of SM increased from 2.16×10¹⁹sping·g^-1 to 4.56×10¹⁹sping·g^-1.The free radical content of MS2 was less than the theoretical value,meaning that free radical generated by the co-pyrolysis was stabilized,indicating that there was a synergistic effect during the process of co-pyrlysis of HDSX with SM.?3?The pyrolysis process of the five samples before and after heat treatment was investigated by TG-Differential TG?DTG?.The pyrolysis process was mainly divided into three stages:?1?dry degassing stage,?2?active thermal decomposition stage,?3?and thermal polycondensation stage.?4?The pyrolysis characteristic parameters of the five samples were obtained from the TG-DTG curves.The?Wmax of HDSX among the five samples was the highest,reaching 86.09%,and the?Wmax of SM was the smallest,which was 20.17%.The T_DTGmax of HDSX was 380?,and the T_DTGmax of SM was 463?.The ?Wmax of MS1 was 32.43%,and its T_DTGmax was 398?.?5?Based on the thermogravimetric change characteristics,the pyrolysis kinetics of the five samples were analyzed.Using the n-stage reaction model,the five samples after heat treatment at different temperatures were analyzed in stages by thermogravimetric analysis.It was found that the activation energy of the heat-treated mixed sample was higher than that of the original mixed sample.