Design And Experimental Study Of Anaerobic Fermentation Reactor

With the development of stockbreeding industry, production of dung has become a social and environmental issue. Anaerobic fermentation of dung as a reliable energy resource is a promising technology to deal with these problems. But owing to over lasting digestion period and less biogas yield in unforced digestion, its economic benefit was reduced in industrialization. In order to settle these problems, we design a complete set of anaerobic fermentation device, calculate the energy, analyse the main influential factors, find out the variation disciplinarians at 35℃ in the trial. These give many powerful reference data for the deeply research. The research contents and achievements as follow:1. Design of a complete set of anaerobic fermentation device. It contents an anaerobic reactor, a constant temperature system by circulating hot water, and a gas collection device.By energy calculation, the design of experimental reactor is feasiable without any heat preservation facilities.2. At a constant situation that keeping the concentration of material and inocula constant, using four reactors with different ratios of hight and diameter in these trials, the radios are 2.18, 4.66, 5, 6.66 respectively. By testing the variation of the pH, COD and gas yield, we research the ratios' influence on the characteristics of cow dung gas generation. The conclusion indicates the ratio of 2.18 is the best, its COD removal rate and gas generation rate are better than others. The secondly better one is the ratio of 5. Using these two better reactors for the same trials, the same conclusion is got.3. Research the variation disciplinarians of the fermentative liquid at different space by testing the data of PH and COD at different heights of reactors everyday. The results indicate that the several variation trends of soluble COD are nearly the same. Before achieve the peak of gas generation, the pH data are distinctly defferent., rising form the bottom to the top.4. Determine the suitable liquid mixture concentration. At the situation of keeping the concentration of inocula constant, comparing the influence of two concentrations, 6% and 7.5%, on COD removal rate, volume gasproduction rate and total gas yield, the results indicate that the concentration of 7.5% is better.5. Comparing different inocula. At the situation of keeping the concentration of liquid mixture constant, comparing the influence of two inocula, biogas broth that has been fermented for 20 days and the mixture of biogas broth and biogas residue, on the characteristics of cow dung gas generation, the results indicate that the latter one is better, for its shorter fermentation period and higher average volume gasproduction rate. Using another reactor for the same trial, the result is consistent.