Separation Of Rice Straw Components And Study On The Technology Of High Value Added Products

Fossil resource is not only the material foundation to the survival of humans, notalso the fundamental driving force of the world development and economic growth.With the speeding up of urbanization all over the world, a high growth momentum offossil resource was presented. In order to solve the problem of resources crisis andrealize the sustainable development strategy, how to make full use of biomass andprepare raw material whose raw material is an urgent problem in the scientificresearch workers around the world.One of the major biomass of crop production system in our country is straw,whose annual output is670million ton. At present, serious pollution is caused bystraw because they are acted as crop waste. However, straw contains abundantcellulose, hemi-cellulose and lignin, which are probably to produce all kinds ofhigh-added-value products. Hence, separating and applying all components of strawcan achieve the protecting of environment and the exploiting of available stock.The purpose of this paper is preparing variety straw-based high added-valueproducts under the condition of not discharging any waste residues. Specific researchis as follows:1. The influence of the time of hydrolysis on the concentration of xylose wasresearched. The result of the experiment indicated that the concentration of xylosesolution was more than13wt%after six times hydrolysis of straw hemi-cellulose. Inaddition, the hydrolyze rate of hemi-cellulose was more than95%. The xylosesolution which was prepared by this method was satisfied to the need of preparingfurfural in the industry.2. The technology of preparing furfural from sugar acid was preliminaryresearched. The result of the experiment indicated that the productive rate was65.31 wt%when the concentration of dilute sulphuric acid was22wt%, NaCl weight was80g and the heating temperature was150℃.The second part, alkaline lignin was obtained from straw residue (I). After theoxidation and de-polymerization via hydrogen peroxide solution, car-boxy-late wasprepared. The results are as follows:1. The color of lignin solution was transformed to transparent because the use ofhydrogen peroxide.2. Under the oxidation and polymerization, meth-oxy was transformed to lignincar-boxy-late.3. The average particle size was decreased to173.5nm from309.5nm.The third part, after removing ash from straw residue (II) by the use of alkalinesolution and de-coloring by the use of hydrogen peroxide, white-colored straw-basedcellulose was obtained. After alkalization and etherification of straw-based cellulose,white sodium carboxyl-methyl-cellulose was obtained. The results are as follows:1. The color of the straw residue (II) was transported to transparent by the use ofhydrogen peroxide solution. The cellulose which was prepared by this method wassatisfied to the need of carboxyl-methyl-cellulose.2. The technology of preparing sodium carboxyl-methyl-cellulose waspreliminary researched. The result of the experiment indicated that the DS andwhiteness of carboxyl-methyl-cellulose was1.756and78.4respectively when theconcentration of sodium hydroxide solution was25.6wt%，the alkaline temperaturewas28℃, the alkaline time was85min, the concentration of chloroacetic acid was63.3wt%, the etherification temperature was65wt%, the etherification time was140min.The innovation of this paper is:1. The result of the experiment indicated that the concentration of xylose solutionwas more than13wt%after six times hydrolysis of straw hemicellulose.2. The white-colored polyatomic solution which has low carboxyl group contentand small average particle size is probably to the synthesis of polyester in industry.3. Because the rich resource of straw, preparing sodium carboxylmethylcellulose from straw instead of purified cotton not only decreased the cost, but also increasedthe market competitiveness of straw.Straw source was completely implied in this paper, and a simple and availablemethod of separating the components was preliminary established. The high valueadded products from these components were furfural, lignin carboxylate, sodiumcarboxylmethylcellulose. This paper provided an important reference value and thedesign basis of the study and comprehensive utilization of industrial production.