The Study on the Feasibility of Improving Rice husk Hydrogen via Batch Tests and SBR

Autor: Meng Hung -Hsieh, 謝孟宏
Rok vydání: 2010
Druh dokumentu: 學位論文 ; thesis
Popis: 98
The Feasibility Study on Promoting Hydrogen Production Rice Husk via Batch Tests and SBR Abstract Due to Facing with the shortage of petroleum and soaring price, biomass energy is by all means becoming the leading alternative energy that is presently under technical development across the world. Anaerobic fermentative hydrogenesis, with its tremendous potentials, is undoubtedly one of the most important energy technologies nowadays. With the huge agricultural wastes produced in Taiwan, this study uses rice husk as substrate in an attempt to find out the feasibility of producing fermentative hydrogenesis from the rice husk and the condition for the optimal operation. First of all, the hydrolization for the substrate must be promoted before the fermentative hydrogenic reaction could be conducted in the study. Therefore, uses 3 strains of Bacillus subtilis(A) as the hydrolytic bacteria bought from BCRC together with the fermentative hydrogenic bacteria cultivated by our lab as the hydrogenic bacteria was used in a series of batch tests and in a 2-stages- reactors continuous input tests for the hydrolization and fermentative hydrogenesis thereby evaluate the feasibility of hydrogenesis by rice husk. According to the results, among 3 strains the maximum hydrolization was got with the increasing of soluble COD up to 34.3% when Bacillus subtilis(A) among 3 strains was used as the hydrolytic bacteria. While the rice husk was used as substrate, initial pH was 5.25, hydrolytic bacteria/hydrogenuc bacteria ratio was 1/4, mixed bacterial liquor substrate ratio was 1/3, and COD concentration was 20000mg/L, the results of batch tests indicate that the fermentative hydrogen production reached 1.29 mmole H2/g-CODin with the optimal pH fell between 4.6 and 6.0. In continuous input tests in which the SBR connected by CSTR reactor in series, to COD concentration was 20000mg/L, total progressive time and HRT were set at 12+36 hr, the pH of front SBR reactor was set at 7.0 and that of rear CSTR reactorwas set at 5.0, and finds that each gram of influent COD produced 3.31 mmole hydrogen and per volume the reactor produced 22.2 mmole hydrogen per day, respectively, which by far exceeds the optimal hydrogenesis, 1.81 mmole-H2/g-CODin acquired at ratio of hydrolytic bacteria/hydrogenic bacteria,1/4 co-cultivated in ASBR. The front SBR reactor entails total progressive time 6 hr to acquire the optimal hydrolization with soluble COD up to 19.5%. In co-culyivated ASBR, the optimal hydrogenesis was got 2.60 mmole H2/g-CODin by co-cultivated at constant pH 5.0, followed by 0.895 mmole H2/g-CODin at constant pH 5.5. As to the influence of pH on COD hydrogensis of per gram the regressional formula YpH,rice husk =Y5.25,rice husk ×0.319│pH-5.25│ for batch test, and YpH,rice husk =Y5.0,rice husk×0.568│pH-5.0│for the continuous inpnt test. Most of the microflora incorporated in this study are either Clostridium or Bacillus subtilis (A). Clostridium emits pale orange fluorescence under UV, Bacillus subtilis (A) emits no fluorescence whatsoever when they are cultivated individually. When Clostridium and Bacillus subtilis (A) are co-cultivated, Bacillus subtilis (A) emits light blue fluorescence. This study compares the hydrogenesis of per unit COD and of per unit volume to that of other literatures and finds that rice husk are an ideal substrate that produces hydrogen satisfactorily, and furthermore, rice husk is inexpensive and available everywhere. Therefore, rice husk is a feasible solution for hydrogenesis. Key words: hydrolysis, anaerobic fermentative hydrogenesis, rice husk, SBR,CSTR,batch test
Databáze: Networked Digital Library of Theses & Dissertations
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