|
With the gradual depletion of fossil fuels, a wide variety of sources in nature cellulose hydrolysis of raw materials to generate reducing sugars and then fermented to produce fuel ethanol has shown a broad market prospects, to solve the increasingly urgent shortage of liquid fuel and food security is extremely significance. And this one, how to make and efficient conversion of cellulose to fermentable reducing sugar is one of the most important step, but also restricting the use of cellulose technical bottlenecks. In this paper, cellulose supercritical hydrolysis reducing sugar production experimental and theoretical study of the system, to lay the foundation for the further use of cellulose in biomass fuel ethanol production. Microcrystalline cellulose hydrolysis of sugar in supercritical water, on a self-designed supercritical hydrolysis test device to study the reaction time, the reaction temperature, the density of supercritical water and solid-liquid ratio and other factors on The conversion rate of reducing sugars, 3,5 - dinitro salicylic acid (DNS) method for the determination of reducing sugars in the product, determine the optimum conditions of the supercritical hydrolysis of cellulose production of reducing sugars. By high performance liquid chromatography (HPLC) to determine the type of sugar hydrolyzate and hydrolysis byproducts, hexose and hydrolysis byproduct variation was analyzed. The results showed that: the cellulose hydrolyzate is a hexose, the the hydrolysis byproducts main component is 5 - (hydroxymethyl) furfural and glyceraldehyde, and degradation products with a prolonged reaction time there is a gradually increasing trend, the other from the hydrolyzate PH value judgment, the hydrolyzate contains organic acids. Using scanning electron microscopy morphology of the hydrolysis residue were analyzed, the results showed that the hydrolysis of cellulose residues gradually pulverized spherical particles. Further, in order from containing cellulose-rich biomass reducing sugar, the paper were rice straw, microcrystalline cellulose, cotton, qualitative filter paper, and after treated with a solution of sodium hydroxide after the rice straw as a raw material, different cellulose supercritical hydrolysis of the raw material of reducing sugars. Study in supercritical conditions in the solid-liquid ratio under certain conditions, a longer reaction time reducing sugar content variation. The optimum reaction time has been more than a few raw materials supercritical hydrolysis. Of different materials hydrolysis of the sugar-producing different reasons. In this paper, on the basis of reference model of cellulose hydrolysis at home and abroad, according to the cellulose in supercritical water hydrolysis characteristics, a homogeneous reaction model to simulate the reaction process, the dynamic response curve. The model was validated and analyzed the reason for the error of the model with experimental data exist.
|