| With the aggravation of water eutrophication,the marine pollution caused by algae has not to be ignored.At the same time,the fossil fuels are running out,Hydrogen which have tremendous potential for development has great potential to replace fossil energy.Some reports showed that Enteromorpha prolifera has access to convenient,and it can be easily degraded by hydrogen bacteria through anaerobic fermentation.It not only provided a way to solve the problem of marine pollution,but also solved energy crises.In this paper,we studied the hydrogen production efficiency of Enteromorpha prolifera by five acids and alkalis,and also studied the method to improve hydrogen production efficiency.Through the research of different kinds of acid and alkali on pretreatment effect of Enteromorpha prolifera,we found the best solution under different conditions.The optimum pretreatment method of Enteromorpha is HCl,the treatment temperature is 60℃,concentration is 0.2 mol/L,treatment time is 24h.Effects of three kinds of activated sludge on the effect of Enteromorpha prolifera fermentation were also studied,the test results showed that the content of VFAs were 1493g/L,TSS decreased by 22.1%,VSS decreased by 20.3%,the concentration of ssCOD was 3775 mg/L,much higher than the other experimental groups,the fermentation effect of aerobic sludge was much higher than others,then we conducted static hydrogen production,test,the result was HCl>NaOH>Ca(OH)2>H2SO4>H3PO4.It has studied the effects of different nitrogen sources,metal ions,fermentation temperature and pH on Enteromorpha prolifera fermentation hydrogen production effects.Results show that,the organic nitrogen source improved the most biomass,and inorganic nitrogen sources improved the most hydrogen production.;The biggest effect of metal ions on hydrogen fermentation is Fe2+;The optimum fermentation temperature is 30℃～37℃,the highest gas production is 28.8ml,reducing sugar utilization rate is 83.3%;the optimum pH range is 5～6,the highest gas production is 38.3ml,reducing sugar utilization rate of 75.2%.Thought hydrogen production experiment of Enteromorpha in IBR,we founded some operating experience and theoretical.In the samll scale IBR,the UASB and CSTR zones,respectively,began mass production by using molasses on the 21th day and 39th day,this proves that the reactor started successfully.Upon entry into stationary phase,CSTR and UASB effluent COD changed with the chang of influent COD,and the hydrogen production was proportional to volume loading.Then we conducted the Enteromorpha fermentation test of 60 days in the pilot IBR.The first stage using molasses lasted 20 days,maximun hydrogen production was 4766L/d in this stage,the total volume loading was 8.69 kgCOD/(m3·d).The second stage was the substrate conversion stage,lasting 27 days,the hydrogen production was the first decline but after rsing.We only input Enteromorpha prolifera in the last stage,this stage lasted 17 days,the hydrogen production increased with increasing volume loading,and decreased with increase of pH and ORP.To judge the importance of the impact factor of hydrogen production and COD removal rate,A back propagation neural network(BPNN)model was built to simulate and predict the reactor performance,which consisted of input layer(4 nodes:influent COD,corn straw content,ORP and pH),hidden layer(6 nodes)and output layer(2 nodes:COD removal rate and biogas production rate).We study on the influent COD,pH,ORP and Enteromorpha content four kinds of factors which were affect the biogas production rate and COD removal rate of reactor by a BP neural network,the results was influent COD>pH>ORP>Enteromorpha content.Comparison of the BP neural network and SVM on the fermentation process simulation and prediction results,showed that SVM’ s effect was better. |
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