scholarly journals Effect of Various Potential Additives on Hydrogen Fermentation During the Co-Digestion of Food Waste and Cow Dung

2020 ◽  
Author(s):  
Chinmay Deheri ◽  
Saroj Kumar Acharya
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Concentration ◽  
Food Waste ◽  
Hydrogen Generation ◽  
Control Sample ◽  
Total Solid ◽  
Cow Dung ◽  
Hydrogen Yield ◽  
Cumulative Yield ◽  
Digestion Process

Abstract The effect of calcium peroxide (CaO2), zinc oxide (ZnO), copper oxide (CuO), and calcium carbonate (CaCO3) as additives during the anaerobic co-digestion of food waste and cow dung is experimentally investigated to enhance the hydrogen fermentation. The maximum concentration of hydrogen in the generated gas is found to be 26.43%, 21.67%, 17.64%, and 20.84% while the cumulative yield of hydrogen remains 114.1, 109.27, 104.87, and 107.38 mL g− 1 Total Solid (TS) with CaO2, ZnO, CuO, and CaCO3 respectively. The sample in which no additive is used (control) exhibits a maximum hydrogen concentration of 17% and a cumulative hydrogen generation of 101.57 mL g− 1 TS in the produced gas. Result reveals an enhancement in the hydrogen concentration up to 9.43% whereas the cumulative hydrogen yield is increased up to 11% with additives compared to the control sample. Overall the hydrogen fermentation can be significantly enhanced with the additives through the anaerobic co-digestion process.

Generation and analysis of biogas from kitchen waste at a small scale

2020 ◽  
pp. 140-148
Author(s):  
Md. Kumail Naqvi ◽  
Mrinal Anthwal ◽  
Ravindra Kumar
Keyword(s):  
Food Waste ◽  
Total Solid ◽  
Small Scale ◽  
Cow Dung ◽  
Retention Period ◽  
Household Level ◽  
Replacement Model ◽  
The Everyday ◽  
Scale Experiment ◽  
Small Period

Biogas is the product of anaerobic vitiation of biodegradable matter. This paper focuses on the need of alternative and green sources of energy at a household level and how biogas produced from the everyday organic waste has the potential and possibility to replace LPG cylinders at houses, shops etc. and empower us to step towards an eco-friendly future. The purpose this small-scale experiment has been to find the perfect input matter that is easy to acquire and which produces the maximum amount of gas from minimum input and within small period of waste retention. Four different types of input waste material containing different quantities of cow dung and kitchen food waste were studied through individual experimental setups. Waste was mixed and kept at room temperature and the pH and total solid concentration of the samples were recorded on regular intervals. From the experiment it was found that the optimum yield of biogas at a small scale, based on the parameters such as retention period, pH and total solid con-centration can be obtained by the use of food waste form households and kitchens. The exact composition has been discussed in this paper. The energy generated by the small-scale generator has also been compared to that of an LPG cylinder and an LPG replacement model has also been presented.

scholarly journals Dual Role of Grass Clippings As Buffering Agent and Biomass During Anaerobic Co-digestion With Food Waste

2021 ◽  
Author(s):  
Debkumar Chakraborty ◽  
Sankar Ganesh Palani ◽  
Makarand M. Ghangrekar ◽  
Anand N ◽  
Pankaj Pathak
Keyword(s):  
Food Waste ◽  
Volatile Fatty Acids ◽  
Hydrogen Generation ◽  
Value Added ◽  
Cost Effective ◽  
Organic Load ◽  
Hydrogen Yield ◽  
Alcohol Production ◽  
Redox Environment ◽  
Buffering Agent

Abstract There is a dire need to replace the chemical buffers that regulate the redox environment in single-stage anaerobic digestion (AD) of food waste (FW). Hence, the applicability of grass clippings (GC) as an eco-friendly buffering agent and biomass during the anaerobic co-digestion of FW was explored. A focus was primarily given on the effects of GC on the redox environment and acidogenesis. Concomitantly the production of volatile fatty acids, hydrogen and methane in mesophilic conditions was monitored. Organic load and substrate to inoculum ratio were kept constant in all the experiments, and no chemical buffer was used. The results revealed that GC regulated the redox environment by inhibiting rapid pH drop in the digester with 10 % GC. The addition of 2, 4, and 6 % GC promoted acidogenesis with increased production of acetic and butyric acids; whereas, 8 and 10 % GC promoted solventogenesis with ethyl alcohol production. Hydrogen generation from the experiments with GC was in the range of 27-30 % of the total biogas, which was marginally higher than from the control (25 %). Methane concentration was negligible in the biogas generated from all experiments. The acidification rate, VFA production/consumption rate, specific hydrogen yield, hydrogen conversion efficiency, and volatile solid removal were maximum and minimum in the reactors with 6 and 10 % GC, respectively. From the above results, it can be concluded that the addition of GC to FW would regulate the sudden pH changes and enhance the production of value-added biochemicals, to make the process cost-effective.

scholarly journals Biogas Quantity and Quality from Digestion and Co-Digestion of Food Waste and Cow Dung

2021 ◽  
Vol 25 (7) ◽  
pp. 1289-1293
Author(s):  
O.M. Ojo
Keyword(s):  
Food Waste ◽  
Biogas Production ◽  
Cow Dung ◽  
Total Production ◽  
Retention Period ◽  
Digestion Process ◽  
Single Substrate ◽  
Cumulative Volume

The aim of this study is to assess the quantity and quality of biogas produced from single substrate digestion of food waste and cow dung as well as co-digestion of food waste and cow dung. Laboratory sized 25 litre plastic biodigesters were used in this study and the digestion processes was carried out for a 30 day retention period. The results revealed that the cumulative biogas production for the single substrate digestion of cow dung was 7,975 ml, the cumulative biogas produced for the single substrate digestion of food waste was 7,742.5 ml while the cumulative volume of biogas produced for the co-digestion of cow dung and food waste was 16,482.5 ml. The results also showed that the total volume of methane produced for the single substrate digestion of cow dung was 955 ml while the total methane produced for the single substrate digestion of the food waste was 765. The total production of methane for the co-digestion of cow dung and food waste was found to be 2,655 ml. This study revealed that though the co-digestion process improved biogas quantity and quality, the percentage methane present in the biogas very low. There would be a need to stimulate the digestion and co-digestion process in order to improve the quality of biogas produced.

scholarly journals Case Study of Anaerobic Digestion Process Stability Detected by Dissolved Hydrogen Concentration

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 106
Author(s):  
Daniela Platošová ◽  
Jiří Rusín ◽  
Jan Platoš ◽  
Kateřina Smutná ◽  
Roman Buryjan
Keyword(s):  
Anaerobic Digestion ◽  
Correlation Coefficient ◽  
Hydrogen Concentration ◽  
Pearson’S Correlation ◽  
Pearson’S Correlation Coefficient ◽  
Digestion Process ◽  
Short Service Life ◽  
Pearson's Correlation ◽  
Dissolved Hydrogen ◽  
Pearson's Correlation Coefficient

The paper presents the results of a laboratory experiment of mesophilic single-stage anaerobic digestion performed to verify the possibility of early detection of process instability and reactor overload by evaluating the course of dissolved hydrogen concentration of the main intermediate. The digestion process was run in a Terrafors IS rotary drum bioreactor for 230 days. The substrate dosed on weekdays was food leftovers from the university canteen. At an average temperature of 37 °C, an organic loading of volatiles of 0.858 kg m−3 day−1 and a theoretical retention time of 259 days, biogas production of 0.617 Nm3 kg VS−1 was achieved with a CH4 content of 51.7 vol. %. The values of the established FOS/TAC stability indicator ranged from 0.26 to 11.4. The highest value was reached when the reactor was overloaded. The dissolved hydrogen concentration measured by the amperometric microsensor ranged from 0.039–0.425 mg dm−3. Data were statistically processed using Pearson’s correlation coefficient. The correlation of the hydrogen concentration with other parameters such as the concentration of organic acids was evaluated. The value of Pearson’s correlation coefficient was 0.331 and corresponded to a p-value of 0. The results confirmed a very low limit of the hydrogen concentration at which the microbial culture, especially methanogens, was already overloaded. The amperometric microsensor proved to be rather unsuitable for operational applications due to insufficient sensitivity and short service life. The newly designed ratio of dissolved hydrogen concentration to neutralizing capacity was tested but did not work significantly better than the established FOS/TAC stability indicator.

High-Purity, CO2-Free Hydrogen Generation from Crude Oils in Crushed Rocks Using Microwave Heating

2021 ◽  
Author(s):  
Qingwang Yuan ◽  
Xiangyu Jie ◽  
Bo Ren
Keyword(s):  
Microwave Heating ◽  
Environmental Impacts ◽  
High Purity ◽  
Oil And Gas ◽  
Hydrogen Generation ◽  
Petroleum Industry ◽  
Petroleum Reservoirs ◽  
Crude Oils ◽  
Hydrogen Yield ◽  
Free Hydrogen

Abstract While the demand for hydrocarbon resources has been continuously increasing in the past 150 years, the industry is, however, criticized for carbon dioxide (CO2) emissions and concomitant global warming concerns. The oil and gas industry also face growing pressures in the ongoing energy transition. Generating and producing hydrogen (H2) directly from petroleum reservoirs has the potential to mitigate environmental impacts while revolutionizing the traditional petroleum industry and enabling it to become a clean hydrogen industry. This paper proposes a novel approach to generate high-purity, CO2-free hydrogen from the abundant oil and gas resources in petroleum reservoirs using microwave heating. In this work, laboratory experiments were conducted to validate this scientific proof-of-concept and examine the roles of crushed rocks, catalysts, and water/oil ratio in hydrogen generation from crude oils in a reactor. A maximum of 63% ultimate hydrogen content is obtained in the generated gas mixtures, while the original CO2content in all experiments is negligible (<1%). Catalysts can promote hydrogen generation by accelerating rate and locally enhancing microwave (MW) absorption to create ‘super-hot spots'. Water also participates in reactions, and additional hydrogen is generated through water-gas shift reactions. The water-oil ratio in porous rocks affects the ultimate hydrogen yield. Overall, this research demonstrates the great potential of using MW heating to generate high-purity, CO2-free hydrogen from in situ petroleum reservoirs. Further research and wide application of this technology would potentially transform petroleum reservoirs to hydrogen generators, thus mitigating the environmental impacts of traditional petroleum industry while meeting the increasing demand for clean hydrogen energy. This technology would also benefit the safe transition towards a decarbonized society.

scholarly journals Nitrogen and cobalt co-doped zinc oxide nanowires – Viable photoanodes for hydrogen generation via photoelectrochemical water splitting

2015 ◽  
Vol 299 ◽  
pp. 11-24 ◽  
Author(s):  
Prasad Prakash Patel ◽  
Prashanth Jampani Hanumantha ◽  
Oleg I. Velikokhatnyi ◽  
Moni Kanchan Datta ◽  
Daeho Hong ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Water Splitting ◽  
Hydrogen Generation ◽  
Photoelectrochemical Water Splitting ◽  
Zinc Oxide Nanowires ◽  
Oxide Nanowires ◽  
Co Doped

scholarly journals Research on hydrogen generation from rapid hydrolysis of aluminum in sodium fluoride solution

2019 ◽  
Vol 118 ◽  
pp. 03048
Author(s):  
Changchun Li ◽  
Yuxin Wu
Keyword(s):  
Hydrogen Production ◽  
Kinetic Model ◽  
Sodium Fluoride ◽  
Hydrogen Generation ◽  
Hydrogen Yield ◽  
Shrinking Core Model ◽  
Fluoride Solution ◽  
Shrinking Core ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

Hydrogen generation from rapid hydrolysis of aluminum in sodium fluoride solution was investigated through a hydrolysis experiment. Rapid and instant hydrogen yield were observed using sodium fluoride as additive. The experimental results demonstrate that the increase of temperature and the amount of additives in a certain range will boost the hydrogen production. The amount of additives outside the range only has an effect on the rapid hydrolysis of the aluminum during the initial stage, but the total amount of hydrogen produced doesn’t increased significantly. Theoretical analysis of the effects of the mixing ratio and the temperature on the hydrogen production rates were performed using the shrinking core model and the kinetic model. The shrinking core model parameter a and k indicate the film change degree of porosity and thickness and the effect of time on the diffusion coefficient. the kinetic model is verified and the activation energy confirming hydrogen yield control by a molecular diffusion process. Correspondingly, mechanisms of Al corrosion in NaF solutions under low and high alkalinity were proposed, respectively.

scholarly journals Heat Exchanger for Bio-Digester under Thermophilic Range

2019 ◽  
Vol 5 ◽  
pp. 79-88
Author(s):  
Prajwal Sapkota ◽  
Laxman Poudel
Keyword(s):  
Heat Exchanger ◽  
Anaerobic Digestion ◽  
Heat Exchangers ◽  
Heating System ◽  
Gas Production ◽  
Cow Dung ◽  
Digestion Rate ◽  
Digestion Process ◽  
Different Temperatures ◽  
Long Time

Bio-gas has been one of the sources of renewable energy and has been used from long time. It is produced by the anaerobic digestion or decomposition of organic compounds and has different process. The digestion process is carried out by bacteria present in the waste and it is highly dependent on the bacteria which work differently on different temperatures. The rate of anaerobic digestion is highest at hemophilic temperature (55°C). Similarly, it is moderate at mesophilic temperature (35°C) and is lowest at psychrophilic (below 20°C). Thus, to attain the highest digestion rate a thermophilic heating system has beend eveloped. The heating system uses five heat exchangers to heat the influent at digester which is of 35m3 volume, to maintain temperature at 56°C. The volume of bio-gas production from this system which uses cow dung as digestingmaterial is about 28 m3 per day.

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