Effect of Organic Loading Rate on Fermentative Hydrogen Production in CSTR

2010 ◽  
Vol 156-157 ◽  
pp. 732-736
Author(s):  
Shuang Gao ◽  
Bing Wang ◽  
Lei Lei Zhu ◽  
Wei Han ◽  
Hong Chen ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Hydrogen Production ◽  
Acid Concentration ◽  
Statistical Correlation ◽  
Organic Loading Rate ◽  
Hydrogen Yield ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
Biogas Yield ◽  
The Impact

This study investigated the impact of five organic loading rates (OLRs) ranging from 16 kg COD/m3-d to 32 kg COD/m3-d on the performance of a continuous stirred tank reactor (CSTR) for biological hydrogen production, with molasses as substrate. Hydraulic Retention Time (HRT) was kept at 6 hours and the temperature 35°C. Oxidation-reduction potential (ORP) varied from -328 mV to -419 mV. The ethanol-type fermentation has been conducted during the process. A positive statistical correlation was observed between OLR and biogas yield; however, it became negative for the OLR of 32 kg COD/m3-d (Fig1). The system maintained the highest average biogas and hydrogen yield of 14.66 L/d and 5.17 L/d at OLR of 28 kg COD/m3-d. Compared with the first stage (16 kg COD/m3-d), ethanol and butyric concentration of the last stage (32 kg COD/m3-d) increased about 2.01 and 3.79 times, respectively; Acetic acid concentration surged around 200 mg/L; Prop ionic acid concentration dropped slightly; Valeric acid concentration, which took a small portion in the volatile fatty acid (VFA), kept low. When OLR was kept at 28 kg COD/m3-d, the average ethanol to acetic acid ratio is 3.90.Thus proved that the optimal OLR for hydrogen production under experimental condition is 28 kg COD/m3-d.

Control of Start-up and Operation in Continuous Fermentation of Bio-Hydrogen Production Reactor

2011 ◽  
Vol 183-185 ◽  
pp. 552-556
Author(s):  
Zhi Qin ◽  
Dan Qin ◽  
Dan Li
Keyword(s):  
Acetic Acid ◽  
Hydrogen Production ◽  
Butyric Acid ◽  
Ph Value ◽  
Continuous Fermentation ◽  
Hydrogen Yield ◽  
Continuous Stirred Tank Reactor ◽  
Fermentation Products ◽  
Biogas Yield ◽  
Acid Type

Bio-hydrogen production from diluted molasses by anaerobic activated sludge was investigated in a continuous stirred-tank reactor (CSTR) under condition of continuous flow in this study. Research shows that the reactor started up under the condition of influent COD concentration 3000mg/L, HRT8h, pH6.5~7.5 and (35±1) °C. The process performed steadily and a dominant butyric acid and acetic acid type fermentation population was established, acetic acid and butyric acid accounted for about 80% in the liquid fermentation products. The effluent PH value was maintained about 5.0. The biogas yield could reach at 4.87L/d while hydrogen yield reached 41.25mL/d under the condition. When influent COD concentration rose to 5500 mg/L, the biogas yield and hydrogen yield as high as 9.45L/d and 119.98mL/d were obtained.

Effect of Organic Loading Rate on Bio-Hydrogen Production in Continuous Stirred Tank Reactor

2010 ◽  
Vol 113-116 ◽  
pp. 1170-1175
Author(s):  
Zi Rui Guo ◽  
An Ying Jiao ◽  
Xiao Ye Liu ◽  
Yong Feng Li
Keyword(s):  
Hydrogen Production ◽  
Loading Rate ◽  
Clean Energy ◽  
H2 Production ◽  
Organic Loading Rate ◽  
Hydrogen Yield ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
H2 Yield ◽  
Distribution Energy

Hydrogen is a kind of ideal clean energy sources. With low energy consumption, environmental protection and other advantages, biological hydrogen production technology become the hotspot of current study home and abroad. The distribution energy technology for producing hydrogen can get hydrogen when deal with waste water. For finding out the industralized feasibility of continuous H2 bio-production,the ability of H2-production via facultative anaerobe,optimum hydraulic retention time(HRT) and optimum organic loading rate(OLR) were aslo studied. With a temperature of (35±1)°C，HRT of 8 h，the CSTR inoculated with activated sludge ,and the progression is increasing organic loading rate gradually. Six OLRs were examined, ranging from 2 to 12 g COD/L.d, with the mass of molasses ranging from 1.3 to 10 g COD/L. While COD was up to 4g/L(OLR 12kg/(m3•d)), all molasses was utilized and the H2 yield was not significantly influenced by OLR. At the intermediate COD of 6g/l (OLR 18kg/(m3•d)), the H2 yield was maximized at about 30 L/d H2 (mol molasses. Conv.), which was 17.9% and 55.9% higher than those of OLR 6 kg/(m3.d) and OLR 12 kg/(m3.d),respectively. When the influent COD concentration raised to 12g/L(OLR 30kg/(m3•d)), the reactor were overloaded, the hydrogen yield decreased drastically，hydrogen evolution rate decreased to zero. Exceeding OLR would arouse great change of internal environment parameters, such as pH, ALK(aikalinity), ORP(oxidation-reduction potential) in CSTR, and the microbial community structure would change while the metabolism of microorganism was inhibited badly.

scholarly journals Simultaneous Biohydrogen and Bioethanol Production from Anaerobic Fermentation with Immobilized Sludge

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Wei Han ◽  
Zhanqing Wang ◽  
Hong Chen ◽  
Xin Yao ◽  
Yongfeng Li
Keyword(s):  
Acetic Acid ◽  
Ethanol Production ◽  
Production Rate ◽  
Anaerobic Fermentation ◽  
Hydrogen Yield ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
Loading Rates ◽  
Ethanol Production Rate ◽  
Continuous Stirred Tank

The effects of organic loading rates (OLRs) on fermentative productions of hydrogen and ethanol were investigated in a continuous stirred tank reactor (CSTR) with attached sludge using molasses as substrate. The CSTR reactor with attached sludge was operated under different OLRs, ranging from 8 to 24 kg/m3·d. The H2and ethanol production rate essentially increased with increasing OLR. The highest H2production rate (10.74 mmol/hL) and ethanol production rate (11.72 mmol/hL) were obtained both operating at OLR = 24 kg/m3·d. Linear regression results show that ethanol production rate () and H2production rate () were proportionately correlated and can be expressed as (). The best energy generation rate was 19.08 kJ/hL, which occurred at OLR = 24 kg/m3·d. In addition, the hydrogen yield was affected by the presence of ethanol and acetic acid in the liquid phase, and the maximum hydrogen production rate occurred while the ratio of ethanol to acetic acid was close to 1.

Characterization of Bio-Hydrogen Production from Carbohydrates with Bacteria Ethanoligenens R3

2010 ◽  
Vol 113-116 ◽  
pp. 1884-1889
Author(s):  
An Ying Jiao ◽  
Yong Feng Li ◽  
Kun Liu ◽  
Bing Liu
Keyword(s):  
Hydrogen Production ◽  
Culture Medium ◽  
Previous Experiment ◽  
Hydrogen Yield ◽  
Continuous Stirred Tank Reactor ◽  
Brown Sugar ◽  
Biogas Yield ◽  
Initial Ph ◽  
Continuous Stirred Tank

An ethanol-based hydrogen producing bacteria Ethanoligenens R3 was isolated from continuous stirred tank reactor used for hydrogen production in previous experiment. Batch culture experiments were operated in this study with the fermentative temperature of 35°C and substrate concentration of 10g/L. The performance of hydrogen production from glucose, brown sugar and starch by Ethanoligenens R3 was investigated. The results show that the optimal substrate used for bio-hydrogen production was glucose with the maximum hydrogen yield of 834 mlH2/L culture. Furthermore, effect of initial pH of the culture medium on hydrogen production was studied. It is demonstrated that Ethanoligenens R3 reached the maximum biogas yield of 1760 ml/L culture with the maximum total VFAs concentration of 3329.39 mg/L at the initial pH of culture medium of 5.5.

scholarly journals Anaerobic treatment of glycerol for methane and hydrogen production

2013 ◽  
Vol 14 (2) ◽  
pp. 149-156 ◽  
Keyword(s):  
Hydrogen Production ◽  
Ph Value ◽  
Anaerobic Treatment ◽  
Microbial Culture ◽  
Batch Reactors ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
Loading Rates ◽  
Fermentative Hydrogen Production ◽  
Initial Ph

This work focused on glycerol exploitation for biogas and hydrogen production. Anaerobic digestion of pure glycerol was studied in a continuous stirred tank reactor (CSTR), operated under mesophilic conditions (35oC) at various organic loading rates. The overall operation of the reactor showed that it could not withstand organic loading rates above 0.25 g COD L-1 d-1, where the maximum biogas (0.42 ± 0.05 L (g COD)-1) and methane (0.30 ± 0.04 L (g COD)-1) production were achieved. Fermentative hydrogen production was carried out in batch reactors under mesophilic conditions (35oC), using heat-pretreated anaerobic microbial culture as inoculum. The effects of initial concentration of glycerol and initial pH value on hydrogen production were studied. The highest yield obtained was 22.14 ± 0.46 mL H2 (g COD added)-1 for an initial pH of 6.5 and an initial glycerol concentration of 8.3 g COD L-1. The main metabolic product was 1.3 propanediol (PDO), while butyric and acetic acids as well as ethanol, at lower concentrations, were also determined.

scholarly journals Processing variables of direct-write, near-field electrospinning impact size and morphology of gelatin fibers

2020 ◽  
Author(s):  
Zachary G. Davis ◽  
Aasim F. Hussain ◽  
Matthew B. Fisher
Keyword(s):  
Acetic Acid ◽  
Acid Concentration ◽  
Near Field ◽  
Fiber Formation ◽  
Direct Write ◽  
Acetic Acid Concentration ◽  
Direct Writing ◽  
Fiber Morphology ◽  
Gelatin Concentration ◽  
The Impact

AbstractSeveral biofabrication methods are being investigated to produce scaffolds that can replicate the structure of the extracellular matrix. Direct-write, near-field electrospinning of polymer solutions and melts is one such method which combines fine fiber formation with computer-guided control. Research with such systems has focused primarily on synthetic polymers. To better understand the behavior of biopolymers used for direct-writing, this project investigated changes in fiber morphology, size, and variability caused by varying gelatin and acetic acid concentration, as well as, process parameters such as needle gauge and height, stage speed, and interfiber spacing. Increasing gelatin concentration at a constant acetic acid concentration improved fiber morphology from large, planar structures to small, linear fibers with a median of 2.3 µm. Further varying the acetic acid concentration at a constant gelatin concentration did not alter fiber morphology and diameter throughout the range tested. Varying needle gauge and height further improved the median fiber diameter to below 2 µm and variability of the first and third quartiles to within +/-1 µm of the median for the optimal solution combination of gelatin and acetic acid concentrations. Additional adjustment of stage speed did not impact the fiber morphology or diameter. Repeatable interfiber spacings down to 250 µm were shown to be capable with the system. In summary, this study illustrates the optimization of processing parameters for direct-writing of gelatin to produce fibers on the scale of collagen fibers. This system is thus capable of replicating the fibrous structure of musculoskeletal tissues with biologically relevant materials which will provide a durable platform for the analysis of single cell-fiber interactions to help better understand the impact scaffold materials and dimensions have on cell behavior.

scholarly journals Performance of Anaerobic Digestion of Chicken Manure Under Gradually Elevated Organic Loading Rates

2019 ◽  
Vol 16 (12) ◽  
pp. 2239 ◽  
Author(s):  
Fei Wang ◽  
Mengfu Pei ◽  
Ling Qiu ◽  
Yiqing Yao ◽  
Congguang Zhang ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Poultry Manure ◽  
Ammonia Nitrogen ◽  
Methane Content ◽  
Chicken Manure ◽  
Continuous Stirred Tank Reactor ◽  
Organic Loading ◽  
Biogas Yield ◽  
Loading Rates

Poultry manure is the main source of agricultural and rural non-point source pollution, and its effective disposal through anaerobic digestion (AD) is of great significance; meanwhile, the high nitrogen content of chicken manure makes it a typical feedstock for anaerobic digestion. The performance of chicken-manure-based AD at gradient organic loading rates (OLRs) in a continuous stirred tank reactor (CSTR) was investigated herein. The whole AD process was divided into five stages according to different OLRs, and it lasted for 150 days. The results showed that the biogas yield increased with increasing OLR, which was based on the volatile solids (VS), before reaching up to 11.5 g VS/(L·d), while the methane content was kept relatively stable and maintained at approximately 60%. However, when the VS was further increased to 11.5 g VS/(L·d), the total ammonia nitrogen (TAN), pH, and alkalinity (CaCO3) rose to 2560 mg·L−1, 8.2, and 15,000 mg·L−1, respectively, while the volumetric biogas production rate (VBPR), methane content, and VS removal efficiency decreased to 0.30 L·(L·d)−1, 45%, and 40%, respectively. Therefore, the AD performance immediately deteriorated and ammonia inhibition occurred. Further analysis demonstrated that the microbial biomass yield and concentrations dropped dramatically in this period. These results indicated that the AD stayed steady when the OLR was lower than 11.5 g VS/(L·d); this also provides valuable information for improving the efficiency and stability of AD of a nitrogen-rich substrate.

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