Experimental Study On The Start-Up And Operational Parameters For Dual System Of Hydrogen And Methane Production By CSTR_Hyd-Ic_Met

In two-phase anaerobic system,acid-producing bacteria and methanogens were physically separated into two series reactors,where optimum environmental conditions for each group of organisms would be provided the best conditions required for the respective.The mutual interference between creatures of different species and uneven metabolic product inhibition can be avoided. Acidogenic phase has a stronger adaptability and buffering capacity to the change of water quality and load,can greatly cut down the effect caused by operating conditions change on the influence of methanogens,and thus can improve the gas efficiency and running stability of the system.In order to start up and run the dual system of hydrogen and methane production,this study used molasses wastewater as fermentation substrate,a continuous flow anaerobic fermentation reactor(CSTR)as acidogenic phase reactor,and a internal circulation anaerobic reactor(IC)as methanogenic phase reactor.The quick start-up of the dual system of hydrogen and methane production and the organic loading rate(OLR)on system energy recovery efficiency were investigated in this paper.In the start-up of the dual system of hydrogen and methane production,experiment firstly studied the influence of hydraulic retention time(HRT)on acidogenic phase and methanogenic phase,so as to determine the optimal operation condition.Results show that:the optimal HRT condition for acidogenic phase was6h and under this condition,hydrogen production rate of3.86L/d and content of28.07%was obtained.In the later period of the start-up proees,methane production rate of6.78L/d and content of43.76was obtained in the methane production system.The acidification rate in hydrogen-production system and methane-producing system were70%and8.63%respectively.With optimal operation condition of acidogenic phase and methanogenic phase,the two-phase anaerobic system for the coproduction of hydrogen and methane was established and the influence of organic loading rate(OLR)on system energy recovery efficiency was investigated.The dual system of hydrogen and methane production was running with35±1℃,HRT was6h in hydrogen-production system and8h in methane-producing system.Results show that:at OLR30kgCOD/(m3·d),the gas produce ability was the largest in CSTR hydrogen-production system,at which the biogas production rate of23.3L/d and hydrogen content of62%was obtained.The hydrogen-production system in the whole operation process stage kept the ethanol type fermentation.The gas produce and methane content in IC methane-producing system was rising from11.23L/d and57%to20.41L/d and74.45%with the improvement of system of organic load.