Study On Hydrogen Production From Vinegar Residue By Anaerobic Fermentation

Hydrogen is a clean renewable energy.Comparing with the other fossil fuels, hydrogen is an ideal,clean and sustainable energy resource for future.It has many advantages,such as:high energy density,high heat conversion,low cost of transportation,and no recontamination.Biological hydrogen production processes, including photosynthesis and anaerobic fermentation,are environmentally friendly and less energy intensive compared to chemical processes.Currently,with the exasperation of energy shortage and environmental pollution,it is very significative to find some new substituted energy,develope the study of renewable energy for protecting the security of energy strategy and reducing the environmental pollution. The fermentative bio-hydrogen process is environment friendly,in which hydrogen can be produced from degrading organic by micro-organisms,reaching the aims: getting rid of wastes and protecting environment.So the fermentative bio-hydrogen process must have a good future.Hydrogen production had been carried out in batch reactor and 5-litre small-scale reactor from industrial organic wastes（vinegar residue） by natural anaerobic microorganisms（cattle manure）,and study of methane production from liquid terminal-products of hydrogen fermentation was conducted.We got the significant study result.Effects of pretreatments of cattle manure and vinegar residue on hydrogen production were studied.The results showed the optimal pretreatment method of cattle manure was to heat in 0.7mol/L NaOH with the solid-liquid ratio of 3:5 by 100℃water for 1h,and the best pretreatment method of vinegar residue was to make the vinegar residue marinated in 0.7%HCl for 24h with the solid-liquid ratio of 2:5.The hydrogen productivity of the pretreated vinegar residue was 4.3 times of those un-pretreated vinegar residue.Hydrogen production had been carried out in batch and a 5-litre scale-up reactor from vinegar residue by natural anaerobic microorganisms.In order to develop the hydrogen production technology,the engineering technique parameters were researched in this thesis.The optimal operation parameters in batch reactor were as follows:fermentative temperature of 35℃,substrate concentration of 175g/L,initial pH of 6.0,and with a 2%supplement of trace metals solution,the maximum hydrogen productivity of 46.91ml/gTS was achieved.The optimal operation condition in the 5-liter reactor was as follows:substrate concentration of 127.5g/L,inoculation concentration of 156.5g/L,fermentative temperature of 37℃,agitator speed of 120r/min,initial pH of 6.0 and 2%supplement of trace metals solution.Under this optimal experimental condition,the 5-liter scale-up reactor obtained a maximum hydrogen productivity of 23.27ml/gTS,the average hydrogen concentration in the biogas reached 50%.Experimental results of metabolites analysis demonstrated that there were acetate, propionate,butyrate,ethanol,H₂,CO₂ and other terminal-products.Methane was not detected in the biogas.Because the butyrate concentration was the highest in all liquid phase-products at all times,it might be butyrate type fermentation of hydrogen production in the 5-litre scale-up reactor.Methane production from liquid terminal-products of hydrogen fermentation by domesticated activated sludge was conducted.From the result we got the highest methane concentration and methane yield of 42.9%and 33.1ml/gTS separately,and the activated sludge could effectively eliminate the volatile fatty acid in liquid terminal-products of hydrogen fermentation.