Research On Selection And Application Of The Immobilization Carrier In Biological Hydrogen Production System

The combustion of fossil fuels has resulted in the climate change and global warming. The clean energy development is in the agenda in almost industrialized nation all over the world. As an attractive energy carrier, hydrogen seems to be one of the best alternatives since it has a high energy yield (122kJ/g). Anaerobic fermentative hydrogen production by using waste water as organic substrates can effectively reduce the environmental pollution. In order to promote the industrialized development of biological hydrogen production technology, more attention has been pay to the optimization of hydrogen production process. Whether strains filtration, optimization of reactor or fermentation metabolic conditions are under-researched aspects.In order to study the effect of immobilization technology for biological hydrogen production process, this study used a continuous flow anaerobic fermentation reactor with molasses as the substrate to compare the feasibility of strengthen suspended growth and immobilized activated sludge biological hydrogen production system. In suspensiongrowth system, it was found that volume loading rate can cause great influence on the sludge biomass inside the reactor, when HRT was4h, the MLVSS decreased from14.48g/L to7.86g/L. Accompanied by reduced biomass, metabolic rate in sludge reactor were suppressed and hydrogen production ability was only1.9624L/d. When d HRT was6h, the temperature35℃and OLR=16kgCOD·m-3·d-1, ethanol type fermentation reactor was established with pH in the range of4.0～4.5and ORP-430mV. The high hydrogen yield of6.258L/d can reach and the highest COD removal rate reached30%.In order to compare with the immobilization system, the experiment used three different carriers, a ctivated carbon, zeolite particles and biological ceramic ring, for reinforcement of activated sludge. The biggest advantage of immobilization technology for biological hydrogen production process is to improve the physical properties of mixed bacteria and the adaptation ability of biological hydrogen production bacteria using immobilized carrier adsorption capacity and effectively. Strengthening the hydrogen producing bacteria growth metabolism have played great role in the optimized fermentation hydrogen production system. Research shows that when HRT was4h, OLR36kgCOD·m-3·d-1, immobilization system could realize efficient hydrogen production and biomass also won’t loss with increased volume loading rate; In addition, according to the different physical properties of the immobilized carrier, more optimization can be obtained.In hydrogen production system with immobilized activated carbon, activated carbon can effectively improve the shock ability of CSTR reactor and decrease the metabolic inhibition of acidification environment for the growth of the hydrogen producing bacteria. It was found that when the temperature was35℃, HRT of4h and influent COD concentration6000mg/L, the maximum hydrogen production of12.06L/d was obtained. In addition, though pH decreased to3.42, the microbial growth kept high and COD removal rate reached40%, which demonstrated that the reactor processed the ability of acid resistance.In the zeolite particles immobilized system, using the ability of heat and acid resistance can also realize the interest for high-temperature fermentation hydrogen production in immobilized technology. Study found that when temperature was35℃, HRT4h, pH=3.6～3.8and OLR36kgCOD·m-3·d-1, biggest hydrogen production of10.81L/d was obtained; And when the temperature was kept at70℃, the maximum hydrogen production of12.39L/d was obtained. Zeolite particles effectively improved the effect of temperature on reactor internal balance, also use the physical properties of heat resistance, in the protection on the basis of the original temperature hydrogen producing bacteria acidophilus, promote the growth of the thermophilic hydrogen producing bacteria.In immobilized ceramic ring system, biological ceramic ring with its large size, high heat resistance and strong adsorption water purification performance is one of the most popular carrier.est results also proved that when temperature was35℃, HRT3h and OLR48kgCOD·m-3·d-1, with ethanol type fermentation reactor can reached hydrogen production of13.48L/d; when HRT was4h and OLR36kgcod m-3·d-1,the hydrogen production of17.16L/d can be arrived. Biological porcelain ring immobilization technology can provide higher adsorption ability and enhance sludge impact resistant ability as well as the acid-heat-resisting ability. In the condition of pH3.60and temperature70℃, the further optimization of the reactor can obtained hydrogen production of18.96L/d and COD removal rate of50%.