Study On The Hydro-Liquefaction Behaviors Of NaoMaoHu Coal And Its Asphaltene

The direct liquefaction hydrogenation experiments of NaoMaoHu(NMH)coal were carried out in a 500mL high pressure batch autoclave.The characteristic and hydrogenation reactivity of NMH and its asphaltene were investigated.The contents of study include the influence of reaction conditions in liquefaction,the formation and behaviors of asphaltene in the liquefaction,the relationship between the structural composition of coal and reaction characteristics,the transformation of coal structure in the hydro-liquefaction,the effect of different conditions on the properities of the coal direct liquefaction hydrogenation oil.The effects of temperature,initial hydrogen pressure,residue time and solvent/coal ratio on NMH direct hydro-liquefaction conversion and fraction yields were investigated.Temperature was the main factor.The conversion and oil+gas yield were increased with the increase of temperature.When residue time was 30 min,the conversion and oil+gas yield of NMH were 69.23%and 43.15%at 320? while the conversion and yield were increased to 96.33%and 79.68%at 430?,respectively.The conversion began to decline at 450?.The yield of PAA was increased to peak at first then decreased with the increase of temperature.The conversion of NMH could reach to 95.71%when the initial hydrogen pressure was 4MPa.High initial hydrogen pressure promoted hydrogenation and inhibitied the production of gas.The effect of residue time was similar to temperature.High solvent/coal ratio could lift up the conversion and oil yield.The conversion and oil yield had the most significant increase when the ratio from 1:1 to 1.2:1.SEM graphs of the NMH raw coal and its liquefaction residues were showed that the part of the coal favor to hydrogenation had sharp edges and corners on the configuration,and increasing the temperature made the condensation morphologically more obvious.The asphaltenes generated from the hydro-liquefaction had hydrogenatablity as well,but the rate and tendency of hydrogenation reactions were lower than the raw coal.The asphaltene was favor to convert to residue instead of oil and gas while the tempreature increased or the residue time extended.The relationship between coal structural characteristics and the hydrogenation liquefaction performance was studied in the liquefaction experiments of NMH coal and BuLianGou(BLG)coal by the 13C-NMR and FTIR.The results showed that the proportion of aliphatic carbon and aromatic carbon in coal is the main factor affecting the conversion rate of hydrogenation liquefaction.The proportion of aliphatic functional groups is positively correlated with the reactivity while the proportion of aromatic functional groups has negative effect.High methylene carbon and methane carbon content are favorable to oil yield.The aliphatic carbon content in raw coal,asphaltenes and residues decreased in turn,which indicates that the aliphatic carbon is the active structure in hydrogenation liquefaction process.The composition of the oil obtained from hydro-liquefactions under different reaction conditions has certain differences.High reaction temperature and long residue time could increase the proportion of aromatics in the oil.High initial hydrogen pressure and solvent/coal ratio could increase alkane content in the liquefied oil.