Co-pyrolysis Performance Of Coal With Different Ranks And Deashed Oil

In this paper,Qinglongshan lean coal(SM),Shenhua long flame coal(CYM),Indonesian lignite(HM)and Huadian oil shale(OSR)were used as the research objects.The acid washed oil shale(OS)was obtained by acid washing and deashing of oil shale.The pyrolysis characteristics of coal and oil shale and their mixture(SMOS,CYMOS,HMOS)were investigated.The samples were pyrolyzed at low temperature(300-500?)in a fixed bed to study the pyrolysis characteristics of SM,HM,OSR,OS,SMOS and HMOS,and to explore the synergistic effect of the co-pyrolysis process between coal and oil shale.The results show that at 500?,SM solids yield is 89.28%and tar yield is 1.42%,HM solids yield is 48.20%and tar yield is 3.17%,OSR solids yield is 78.46%and tar yield is 5.38%,OS solids yield is 38.90%and tar yield is 7.60%.The solid yield of SMOS is 73.41%and the tar yield is 6.74%,which is higher than the theoretical value of 3.27%.The solid yield of HMOS was 46.71%and the tar yield was 10.58%,which was higher than the theoretical value of 4.50%,indicating that the addition of OS could promote the pyrolysis degree of coal and improve the tar yield.In situ infrared spectroscopy was used to study the changes of typical functional groups of SM,CYM,HM,OSR,OS,SMOS,CYMOS and HMOS in the pyrolysis process in real time and online.The FT-IR spectra were fitted by the second derivative method using peakfit software.The results showed that the content of-OH in SM,CYM,HM,SMOS and CYMOS decreased monotonously with the increase of temperature.The content of-OH in OSR and OS increased first and then decreased.The free-OH in HMOS decreased first and then increased,and the bound-OH increased gradually;The carbonyl/carboxyl C=O of eight samples increased gradually;The aliphatic-CH₃/-CH₂-in SM,CYM,HM,SMOS and HMOS decreased gradually,indicating that the trend of demethylation was significantly higher than that of demethylation;The number of aliphatic-CH₃/-CH₂-in OSR,OS and HMOS increased gradually,indicating that the demethylation trend was lower than that of demethylation.The fast pyrolysis characteristics of OSR,OS and SMOS were studied by pyrolysis gas chromatography-mass spectrometry(Py-GC-MS),and the product distribution of samples at different final pyrolysis temperatures was analyzed.The results showed that the pyrolysis products of OSR,OS and SMOS were mainly oxygenated compounds,accounting for 59.01%,60.24%and 87.99%of the total products,respectively;The relative content of aromatics was 1.23%,5.51%and1.04%respectively.The relative content of OSR and OS lipids increased first and then decreased with the increase of temperature,while the relative content of esters in SMOS increased gradually with the increase of temperature;The relative content of alcohol compounds in OSR decreased monotonously with the increase of temperature,and the alcohol compounds in OS showed a"double peak"rule,while the relative content of alcohol compounds in SMOS increased first and then decreased with the increase of temperature.