| The liquefaction of Shengli brown coal was investigated in the sub/supercritical ethanol system.Some factors which could influence the liquefaction reaction,such as the reaction time,reaction temperature and the solid-liquid ratio were tested with the single-factor test method.The results shown:(1)In different reaction time,as the reaction time increases,the conversion rate and oil yield gradually increase.When the reaction time is too short or too long,it is not conducive to the removal of hydroxyl groups in the liquefied oil.At different reaction temperatures,increasing the temperature favors the hydrogenation reaction and the removal of the ether bond.With the increase of solid-liquid ratio,the intensity of the hydroxyl peak was enhanced,indicating that the ratio of the solid solution was not conducive to the removal of hydroxyl groups.(2)The experimental conditions were solid-liquid ratio1:30,60 m L anhydrous ethanol,the rotation speed was 400r/min,and the reaction temperature was 290 °C.At the end,the conversion rate and oil yield reached 54.62 % and 54.52 % respectively.The PAA ratio was 1 at solid-liquid ratio.: At 30 min the maximum is 12.95 %.In the system of sub/super critical ethanol,this article conducts a liquefaction experiment on Salix psammophila by adopting the one variable statistical method,detects the influence of reaction time,reaction temperature,solid-liquid ratio on the liquefacient reaction.This article then analyzes the changes of the liquefaction product components and the liquefaction residue with the increase of time by utilizing methods such as infrared spectroscopy and thermogravimetry,etc.The results indicate that:(1)The suitable technological conditions for the Salix psammophila liquefaction are as follow: reaction temperature: 290 ?,the reaction time: 45 minutes,the volume of ethanol: 60 m L,solid-liquid ratio1:30.The liquidation under such conditions is 72.08 %,oil yield was 25.63 %,the asphaltene PAA was 2.99 %.(2)The results of the infrared analysis on the liquefied products and the solid residue indicate that the peak pattern of liquefied liquid products and the solid residue doesn't have significant changes 10 min after the 10 min reaction time.Such results indicate that during the liquidation process,the hemicellulose and lignin in the Salix psammophila components first degrade with some celluloses still remaining in the residue.The structure of the liquefied products is complicate with the main components being alcohols,aldehydes,esters,phenols and aromatic hydrocarbons,etc.(3)The results of thermogravimetric analysis on the Salix psammophila solid residue indicate that the content of cellulose has a decreasing tendency with the extension of the reaction time.Such tendency indicates that extension of the reaction time will enhance the degradation of cellulose.The co-liquefaction of Salix psammophila and Shengli brown coal was investigated in the sub/supercritical ethanol system.Some factors which could influence the co-liquefaction reaction,such as the Salix psammophila and coal mass ratio,reaction time,reaction temperature and the amount were tested with the single-factor test method.The changes of liquefied product composition and liquefaction residue with the increase of reaction time were analyzed by means of infrared analysis,thermogravimetric analysis and XRD.The results shown:(1)The optimal liquefaction reaction conditions were: The quality ratio of Salix psammophila and Shengli brown coal 50:50,reaction temperature 290 ?,reaction time 90 min,anhydrous ethanol volume 60 mL,the highest conversion rate could reach 66.65 %,oil yield was 42.59 %,the asphaltene PAA was 7.88 %.(2)The lignite would not be fully liquified under the conditions of the reaction,Salix psammophila played a certain promoting role for the Shengli brown coal liquefaction process. |
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