| As the depletion of fossil energy and the deterioration of ecological environment, seeking alternative of fossil energy, the renewable clean energy, has become a research hotspot. The energy-oriented utilization of energy grasses is also a research hotspot in recent years.This paper selected king grass, grassiness, switchgrass and alfalfa, this four common energy grasses as raw materials for photo-hydrogen production and studied their photo-hydrogen production capabilities respectively. And Firstly used cellulase enzymatic hydrolysis pretreating four energy grasses and using enzymatic hydrolysate of four different energy grasses as substrates for photo-hydrogen production. Took cumulative hydrogen production and hydrogen production rate as index to contrast photo-hydrogen production capabilities of different energy grasses. Then used modified Gompertz equation to regression analyse hydrogen production process, and verified the technical feasibility of using energy grasses as raw materials for photo-hydrogen production. And used alfalfa, which has the best hydrogen producing capability, as the substrate for orthogonal experiment. Took three of the most significant impact on hydrogen production, light, temperature and initial p H as factors,designed a three factor and three level orthogonalexperiment. And conduct intuitive and variance analysis with the results of the orthogonal experiment to get the best hydrogen production process conditions.The results of the experiments showed that,(1)Through the determination of the main components of king grass, grassiness, switchgrass and alfalfa, the cellulose and hemicellulose contents of this four energy grasses was 56.19%、54.14%、61.11% and 57.13% respectively, the main ingredients of this four energy grasses were similar to crops straw, this commonly used raw materials for photosynthetic hydrogen production, like wheat, corn and rice straw. This result indicated the four energy grasses has a good energy conversion material basis.(2) In the circumstances of 10g/L substrate concentration, enzyme load 100mg/g energy grass, 50°C enzymolysis temperature, 48 h enzymolysis time, the concentration of reducing sugar of king grass was 5.14mg/m L, the concentration of reducing sugar of grassiness was 4.04mg/m L, the concentration of reducing sugar of switchgrass was 2.27mg/m L, the concentration of reducing sugar of alfalfa was 5.34mg/m L. The concentration of reducing sugar of king grass and alfalfa was very close, and their concentration of reducing sugar was higher above switchgrass and grassiness. The concentration of reducing sugar of switchgrass was the lowest among these four energy grasses.(3)In the circumstances of 30% inoculum size,30°C,2000 lxilluminance, fermentation time 120 h, among these four energy grasses, the hydrogen producing capability of alfalfa was the best, king grass following it closely, the hydrogen producing capabilities of switchgrass and grassiness were feeblish. The cumulative hydrogen production of king grass, switchgrass, grassiness and alfalfa was respectively 75.3,27.2,26.1 and 81.6m L; The maximal hydrogen production rate was 7.83,3.5,4.33,14.75 m L/(h·L) respectively.(4)The results of the orthogonal experiment showed that, in the level range as taken, the primary and secondary sequence of impact over hydrogen production for energy grass was temperature, light and initial p H. And the analysis of variance suggested that the impact of temperature and light were significant, while the impact of initial p H was non-significant. According to the average level of various factors, the optimum technical conditions was temperature 30°C,p H7, illuminance3000 lx.(5) Using energy grasses as raw materials for photo-hydrogen production is feasible. And combined this kind of green biomass resources, energy grass, with photosynthetic biological hydrogen production technology can not only improve the ecological environment, but also produce clean hydrogen energy, has significant social, environmental and economic benefits as well. |
PDF Full Text Request