Study On The Degradation Of Straw Cellulose And Producing Straw Microcrystalline Cellulose

Energy crisis and environmental problems are the main problems to solve among the human society's development, along with the world population growing and industrialization improving, energy consumption gradually increased, while the global fossil fuel gradually reduced. At the same time, a large number of cellulose materials were used as waste or directly as fuel, such as straw, grass, etc. it was not only a waste of energy, but also caused new pollution, However, using these wastes as raw materials of biomass energy can alleviate some of the future energy problems caused by shortage of fossil materials, and now this is an important direction that most countries in the world exploit and use biomass.Between the straw cellulose of dilute acid cellulose degradation, catalyst played a significant role in the reaction. The reaction temperature, pressure and phosphorous acid concentration all have an optimal value, that is, temperature 100℃～150℃, and pressure in 2.5 MPa above, but not the bigger the better, acid concentration was depending on the production request because the greater the acid concentration, the easier to break the cellulose key.In the straw cellulose of concentrated acid degradation experiments, the optional conditions were: sulfuric acid concentration 65%, liquid-solid ratio(mL/g)8: 1, reaction time 2h, temperature 40℃, and at this time, the reducing sugar yield was 66.75%.In addition,it was also discussed the feasibility of using microwave acid degradation of straw cellulose to produce microcrystalline cellulose(MCC). The results indicated that the best hydrolisis condition was the hydrochloric acid concentration was 6%, reaction time 10min, microwave power 231W, ratio of liquid to solid (mL/g) 20: 1. Under this conditions, the energy consumption was only 23.1% of conventional heating methods, the product yield was 87%, average degree of polymerization 183, crystallinity 88.8%. The product's analysis result confirmed that microwave acid degradation could damage the amorphous region of straw fiber structure, increase the products crystallinity, reduce molecular polymerization degree, but the composing of cellulose molecule did not change.