Study On High Concentrated Atmospheric Acid Hydrolysis Effect Of Straw Raw Material

Rayon pulp is a kind of high alpha cellulose content with an increasing market demand, but because of the traditional rayon pulping raw material especially linters supply shortage seriously, it becomes more and more imperative to expand the applicable scope of rayon pulp in order to satisfy the production of rayon pulp. "The rayon pulp process with straw raw material resource utilization" is a biomass resources comprehensive utilization technology of hydrolysate and balancing with rayon pulp production. This paper is one of the basic research of such technology’s application, its purpose is to form the foundation for forming a short extruder acid hydrolysis process under the laboratory condition researching the basic application effect of high concentrated atmospheric acid hydrolysis process;and also lay a foundation for further resource utilization of acid hydrolysate after researching the rayon pulp quality and pentose sugar content in the hydrolysate, meanwhile charactering the chemical components of hydrolysate preliminarilyThis study bases on the straw raw material rayon pulp production process trough sulfate rocess after acid rehydrolysis. Analyze the chemical components of straw firstly and discusses the best high concentration atmospheric acid hydrolysis process primarily, and then analyze the finally rayon pulp quality. This research also characters and analyzes the active constituents of acid hydrolysate systematically and analyzes its resource utilization in theory.Through the analysis of chemical composition of straw raw material, the straw used in this research has higher pentose sugar content and more ash content, but with no obvious difference in other chemical components compared with other straw raw material and as a result to be a representative straw raw material.In the acidic hydrolysis technology research, this study obtains the best technology through the preliminary orthogonal experiments L9 (33), and based on this to further optimize process. The best technological condition based on the pentose sugar removal rate and alpha cellulose content as the evaluation index is:straw concentration is 20%, sulfuric acid concentration is 7%, reaction time is 90 minutes and reaction temperature is 95℃. Under this optimum process, the pentose sugar removal rate after acid hydrolysis treatment is 67.31%. The raw material after sulfuric acid hydrolysis undergoes sulfate cooking and two sections hypochlorite sodium bleaching and hydrochloric acid added treatment processing, the finally rayon pulp is with a alpha cellulose content as 90.2034%, which other indexes basically meet the rayon pulp quality standards.At the same time, this research determines the polysaccharide, simple sugars, polyphenols qualitatively and quantitatively in the acid hydrolysate, the results show that:under this process, the total sugar content is 54.67 mg/mL (xylose calculate, similarly hereinafter), among which the pentose sugar content is 29.36 mg/mL; The monosaccharide in hydrolysate mainly is xylose, with the content of 23.03mg/mL, but glucose is only 3.94 mg/mL. In addition, there is a high amount of polyphenol compound in this acid hydrolysate with a content of 23.5 mg/mL (gallicacid calculate). Therefore, in these conditions, acid hydrolysis principally is hemi-cellulose hydrolysis, and cellulose hydrolysis reaction is rare. Based on the analysis of the acid hydrolysate active constituent, we advice this acid hydrolysate under experimental conditions can be at least for ethanol and xylitol fermentation production.