Start-up And Stable Operation In Continuous Fementative Hydrogen Production System

The development of modern industry and scientific and technological progress created a brilliant human society, civilization and material wealth, but it brings a deal of problems to the survival of the environment as well. With the development of society, the situation of energy shortage becomes more and more serious. New energy—hydrogen act as a better options for substituting traditional energy. Biotechnology of hydrogen production by fermentation, using biomass as raw material to produce hydrogen, a kind of renewable energy matter, conforming to the sustainable development requirement, is one of the important pathways for environmental pollution control and clean energy demand, and this high technology with broad application prospect has attracted many countries all over the world. Based on research status of bio-hydrogen producing process in the world, the reserch and the development of high efficiency, stability and maneuverability, will accelerate the industrialization of bio-hydrogen production.Therefore, a lot of researches have been done on biohydrogen production from fermentation. The common fermentation types of biohydrogen production from fermentation include propionic acid type fermentation,but yric acid type fermentation and ethanol type fermentation,and the last is regarded as the optimal one for the biohydrogen production from fermentation proeess. Ethanol and acetic acid are the liquid primary product of ethanol-type fermentation which has achieved the highest quantity of biogas and content of hydrogen.Furthermore,ethanol type fermentation can keep the fermentation course of biohydrogen production from fermentation more steadily than the other two fermentation types.In order to make biohydrogen production from fermentation process achieved ethanol fermentation type as quickly as possible, control parameters of the start-up process were investigated by running different organic loading rate (OLR) and the theory of biohydrogen production from fermentation was discussed in this Paper. A certain acidogenic fermentation type could be obtained by controlling the organic volume loading rate (OLR) and the pH of biohydrogen production from fermentation process. CSTR reactor engineering control parameters for:temperature (35±1)℃and HRT 6 h. CSTR reactor was investigated the concentration of COD as 2000-8000 mg/L range on the system performance of hydrogen production. The major production of liquid fermentation was ethanol and acetic acid indicated that the reactor achived the quiek start-up of ethanol fermentation type successfully.The continuous stirred tank reactor (CSTR) for bio-hydrogen production was operated under the organic loading rates (OLR) of 8-32 kg COD/m3 reactor/d (COD:chemical oxygen demand) with molasses as the substrate. Increasing substrate concentration (2000-6000 mg/L) gave better biomass content and hydrogen production, signifying that the average cellular activity for H2 production may be enhanced as the substrate concentration increased. The overall maximal biogas and hydrogen production yield were 23.49 L/d and 8.19 L/d, respectively, both of them occurred at 6000 mg/L. However, the biomass content and hydrogen production yield tended to decrease as the substrate concentration increased to 8000 mg/L, suggesting that granular sludge formation and cellular activity for H2 production may be inhibited at high substrate concentration. The gas phase H2 content did not vary considerably regardless of changes in substrate concentration. This reflects that the CSTR was a relatively stable H2-producing system.