Study On The Integrated Technology Of Bio - Ethanol Tubular Membrane For Cellulose Fermentation

Biomass energy is a renewable energy, many countries put biomass energy to an important position and formulated the corresponding research and development program,which is the fastest development of bioethanol. It is the most feasible and effective way to prepare bioethanol by using low-cast and extensive source of cellulose. China is a big agricultural country, a large number of straw burning has become a big social hazard in our country; With the development of economy and the increase of population, a lot of solid wastes are produced, which is a large proportion of the waste paper which belongs to the lignocellulose resources. Therefore, the use of lignocellulose material for the preparation of bio ethanol can solve the problem of energy shortage in China, but also can alleviate the environmental problems caused by the unreasonable treatment.First, the enzymatic hydrolysis of cellulose was studied. The optimum conditions for the hydrolysis were summed up as follows by orthogonal experiment and a series of verification experiments were carried out to reduce the error and improve the accuracy of the experimental data. The experimental results show that:The glucose standard solution maximum absorption wavelength is 540 nm, the ratio of materials to solvent was 1:10, pH value was 4.6, enzyme dosage was 1.1 g, temperature was at 45℃, saccharification time was 12 h. Under the optimal condition, the concentration of enzymatic hydrolysate,the conversion rate and ratio of cellulose are up to 14.6 g/L, 1.21 g/(L·h),19.3%.Second, Optimal conditions for ethanol fermentation was determined. Four factors were selected for single factor experiment, including fermentation time, inoculating amount, pH value, fermentation temperature. On the basis of single factor experiment, the orthogonal experimental conditions were determined and the optimal fermentation conditions were obtained. The experimental results showed that the optimal experimental conditions:fermentation time was 27 h, the inoculating amount was 9%, pH value was 6.2 and fermentation temperature was at 35℃.Finally, the recycling of cellulase and yeast by using the tubular ultrafiltration membrane was discussed. The tubular membrane is used to separate the enzymatic hydrolysate and get the filtration liquid and the solids containing cellulose and cellulase. The solids can be used to next enzymatic hydrolysis process. The result shows that the cellulase can be reused 12 times and the total conversion ratio of cellulose is up to 77.6%.Similarly, after the completion of ethanol fermentation, yeast was recycled by tubular ultrafiltration membrane. The content of ethanol in the first increased and then decreased, which indicates that there was a process of yeast propagation. So cellulase and yeast to make use of tubular membrane recycling achieved the purpose of reducing production cost, and the experimental operation is simple.