Study On Effect Of Alkali Pre-Extraction On Subsequent Cooking To Bagasse And Mechanism

Most of hemicellulose and lignin, which was dissolved in boiling waste liquid, could not effectively used. It mainly displayed in the three aspects:first, hemicellulose consumed the chemical medicine and increased cooking alkali; second, most of hemicellulose with black liquor improved the black liquor viscosity; Third, much of hemicellulose was easily beated, while the internet filtering water is poor, which can not fit to the high speed paper machine. Through pretreatment, most of hemicellulose was translated and utilized to produce alcohol. It achieved the high value utilization.this paper firstly used single control method. Secondly, combining the effect of alkali pretreatment on the properties of the pulp and paper, gain the optium conditions of pectinase bagasse. At last, the pretreatment mechanism was probed by fiber determination system, FTIR and SEM. The results were as follows:1. With increment of temperature or time, the bagasse yield was dropping, the solid content and pentosan yield was rising.2. Theresults of orthogonal analysis showed that the most important factor for straw yield and pentose yield is the alkali amount, extraction temperature, then the reaction time, and finally the liquid ratio. 3. By changing different alkali extraction condition, it found:as the increase of extraction temperature or the reaction time or the alkali amount, the yield and Kappa of the extraction bagasse pulp values have decreased in varying degrees, alkaline residue of black liquor decline after rising, whiteness and tearing index of the paper had be rising, burst index declined.4. Combined with the performance of subsequent pulp and paper, The optimum condition of pectinase pretreatment was:the highest temperature130℃,holding time50min, liquid ratio1:8, alkali amount6%. At the same time, the poly pentose yield of the extraction liquid can reach about7.0%.5. The yield and Kappa afrer extraction are closely to not, and amount of the residual alkali, white degree, tear index and burst index are higher than the control.6. Through studying the mechanism of the alkaline pre-extraction, the results show that (1) after alkali extraction, cellulose, hemicellulose, and lignin, benzyl alcohol extract and the composition are correspondingly reduced;(2) through the FTIR analysis, the alkali pre-extraction can disconnect ether and ester keys between lignin and carbohydrates.(3) By SEM, the surface of bagasse fiber became rough, appeared damage and crack.