Effects Of Preliminary Hydrolysis Strength On Lignin Ethanol Extraction Of Acacia Wood

Acacia wood as an important plant fiber raw material has significant social and environmental benefits in the comprehensive utilization of pulp and paper industry.In this paper,we will combined pre-hydrolysis with ethanol extraction lignin,That is,the hemicellulose in the raw material is extracted from pre-hydrolyzate before ethanol extraction lignin,to effective separation of hemicellulose,cellulose and lignin.At the same time,the rest of the waste liquid from the extracted hemicellulose reuse to ethanol extraction lignin;we also discusses the changes of chemical components in Acacia wood before and after the pre-hydrolysis,and study the effects of acid reuse on ethanol extraction of lignin.And provide reference for the further application of biomass refining concept in pulp and paper industry.It was found that the content of total cellulose and polypHenols in the pre-hydrolyzed half-sheet decreased with the increase of P factor in the pre-hydrolysis process,and The content of the Klason lignin and acid soluble lignin decreased with the increase of P factor,but the content of benzene-alcohol extract increased with the increase of P factor.And the content of the chemical components in the pre-hydrolyzed half-piece was similar under the same P factor.The pH of the pre-hydrolyzate decreases rapidly with the increase of the P factor,and then tends to be gentle.the change trend of the acid soluble lignin base in contrast to the pH.The content of ash in the precursors decreased first and then stabilized,while the content of volatile components increased with the increase of P factor.At the same time,with the increase of P factor,the prehydrolysis conditions increased,the yield of pre-hydrolyzed wood chips decreased and finally stabilized.The content of monosaccharides in the pre-hydrolyzed solution increased with the increase of the P factor,and the content of polysaccharide increases with the increase of P factor,but decreases when P factor is greater than 196.and the total amount of the polysaccharide reached the maximum of 11.4 g when the P factor was 196.The content of organic acids in the pre-hydrolyzate increased with the increase of the P factor,and reached the maximum of 6.55 g/L at the time of the P factor of 1000.In this paper,we also discussed the effect of P factor on hemicellulose extraction.It was found that the increase of hemicellulose was increased and then decreased with the increase of P factor,and reached the maximum value of 4.97 g/L at the P factor was 196.The effects of P factor on ethanol extraction of lignin were also discussed,it was found that the increase of lignin content increased with the increase of P factor,in the P factor of 600 to reach the maximum 11.91g(100g dry wood chips);In discussing the effect of acid reuse on ethanol extraction of lignin,found that under the same holding time recycling acid is more than the number of don't reuse acid extraction of lignin,and the increase of the lignin content was increased with the holding time,and reached the maximum value of 13.13g(100g dry wood chips)at the holding time of 110 min;It was found that the content of hydroxyl in the lignin structure increased with the pre-hydrolysis,and the absorption peak of the conjugated carbonyl group and the absorption peak of the nonconjugated carbonyl group or carboxyl group gradually increased,and the relative intensity of the absorption peak of the lignin-type ether type unit decreased.The change of average molecular weight showed that the weight average molecular weight and the number average molecular weight of the lignin in the wood were higher than those in the raw material.Compared to recycle acid and not recycling acid extracting lignin infrared spectrum,hydroxyl content in the recycle acid extraction of lignin was higher than not reuse acid extraction of lignin,and recycling of acid extracting lignin of absorption peaks of the conjugated carbonyl and carboxyl and benzene ring,conjugated carbonyl absorption peak C-H plane deformation vibration absorption peak is better than not recycling acid absorption peak intensity,but the lilacs nuclear acid absorption peak intensity lower than don't recycle of the absorption intensity.