Biogas use as fuel in spark ignition engines
- Kukoyi, T.O., Muzenda, E., Akinlabi, Esther Titilayo, Mashamba, A., Mbohwa, Charles, Mahlatsi, T.
- Authors: Kukoyi, T.O. , Muzenda, E. , Akinlabi, Esther Titilayo , Mashamba, A. , Mbohwa, Charles , Mahlatsi, T.
- Date: 2016
- Subjects: Biogas , Spark ignition engines , Substitute fuel
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217660 , uj:21667 , Citation: Kukoyi, T.O. et al. 2016. Biogas use as fuel in spark ignition engines.
- Description: Abstract: This paper reviews the utilization of biogas in spark ignition engines with a view to making a case for it as an efficient substitute fuel for petrol. However, its gaseous nature which accounts for its low volumetric density implies that apart from the basic modification needed to accommodate the fuel, the engine might need further alterations to get the best from this relatively low cost and readily available fuel. Various modes of enhancing performance particularly methane enrichment, prechamber combustion, alteration of ignition parameters, increasing compression ratio and addition of hydrogen to improve performance and emissions were drawn from previous works to validate its efficiency as a viable substitute fuel in SI engines.
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- Authors: Kukoyi, T.O. , Muzenda, E. , Akinlabi, Esther Titilayo , Mashamba, A. , Mbohwa, Charles , Mahlatsi, T.
- Date: 2016
- Subjects: Biogas , Spark ignition engines , Substitute fuel
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217660 , uj:21667 , Citation: Kukoyi, T.O. et al. 2016. Biogas use as fuel in spark ignition engines.
- Description: Abstract: This paper reviews the utilization of biogas in spark ignition engines with a view to making a case for it as an efficient substitute fuel for petrol. However, its gaseous nature which accounts for its low volumetric density implies that apart from the basic modification needed to accommodate the fuel, the engine might need further alterations to get the best from this relatively low cost and readily available fuel. Various modes of enhancing performance particularly methane enrichment, prechamber combustion, alteration of ignition parameters, increasing compression ratio and addition of hydrogen to improve performance and emissions were drawn from previous works to validate its efficiency as a viable substitute fuel in SI engines.
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Studies on the improvement of biogas production from anaerobic digestion of animal wastes
- Authors: Sebola, Mmabyalwa Rebecca
- Date: 2015
- Subjects: Biogas , Sewage - Purification - Anaerobic treatment , Renewable energy sources , Biomass energy
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/57296 , uj:16377
- Description: Abstract: The unsustainability of intensive reliance on fossil fuels and none-renewable resources as the main sources of energy, frequent rises in energy prices, the need for climate change mitigation and environmental protection have intensified the need for green energy. In this respect, green energy, in the form of biogas, has gained increased attention as a cost effective and environmentally cautious approach. This dissertation presents various studies aimed at improving the biogas production from anaerobic digestion of animal wastes. The experiments were conducted using the batch scale mesophilic tests. Characterisation studies (ultimate and proximate analysis) were conducted to identify key characteristics of the selected feedstocks. In addition, an economic assessment on the feasibility of anaerobic technology was conducted. The waste had average moisture content (MC) ranging from 7 – 34% and 70 – 81% for the dry and wet samples, respectively. The average volatile matter (VM) varied between 44 – 58% with the C/N for CD, CM, PM and SW being 26.20, 8.13, 17.64 and 8.57, respectively. Decreasing the particle size of the feedstock increased the amount of biogas significantly by increasing the total surface area of the material exposed to the anaerobic microbes. At optimal particle size (25μm), methane production was 3 – 30 % higher as compared to that of 100μm and above. Highest methane yields were achieved from CD to CM, PM and SW at ratio of 1:1:1:1. At optimum temperature (40˚C), the highest methane yield (62% CH4/ d) was obtained on Day 6. Adding 50% VS resulted in more methane yields (64% CH4/d) than 30 and 40%. An introduction of 40% recycled liquid and 60% fresh water to the digester gave the best performance, with 73% CH4/d of biogas produced within 5 days. Soaking the feedstock prior digestion improved both the methane and biogas yields and stability of the process. An economic evaluation over a period of 5 years with 8 hours daily operation and a breakeven of 1.5 years was assessed. The proposed model has debt repayments of R 2,478,551 with the total revenue from years 2 – 5 being R 2,360,800, R 2,930,158, R... , M.Tech. (Chemical Engineering)
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- Authors: Sebola, Mmabyalwa Rebecca
- Date: 2015
- Subjects: Biogas , Sewage - Purification - Anaerobic treatment , Renewable energy sources , Biomass energy
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/57296 , uj:16377
- Description: Abstract: The unsustainability of intensive reliance on fossil fuels and none-renewable resources as the main sources of energy, frequent rises in energy prices, the need for climate change mitigation and environmental protection have intensified the need for green energy. In this respect, green energy, in the form of biogas, has gained increased attention as a cost effective and environmentally cautious approach. This dissertation presents various studies aimed at improving the biogas production from anaerobic digestion of animal wastes. The experiments were conducted using the batch scale mesophilic tests. Characterisation studies (ultimate and proximate analysis) were conducted to identify key characteristics of the selected feedstocks. In addition, an economic assessment on the feasibility of anaerobic technology was conducted. The waste had average moisture content (MC) ranging from 7 – 34% and 70 – 81% for the dry and wet samples, respectively. The average volatile matter (VM) varied between 44 – 58% with the C/N for CD, CM, PM and SW being 26.20, 8.13, 17.64 and 8.57, respectively. Decreasing the particle size of the feedstock increased the amount of biogas significantly by increasing the total surface area of the material exposed to the anaerobic microbes. At optimal particle size (25μm), methane production was 3 – 30 % higher as compared to that of 100μm and above. Highest methane yields were achieved from CD to CM, PM and SW at ratio of 1:1:1:1. At optimum temperature (40˚C), the highest methane yield (62% CH4/ d) was obtained on Day 6. Adding 50% VS resulted in more methane yields (64% CH4/d) than 30 and 40%. An introduction of 40% recycled liquid and 60% fresh water to the digester gave the best performance, with 73% CH4/d of biogas produced within 5 days. Soaking the feedstock prior digestion improved both the methane and biogas yields and stability of the process. An economic evaluation over a period of 5 years with 8 hours daily operation and a breakeven of 1.5 years was assessed. The proposed model has debt repayments of R 2,478,551 with the total revenue from years 2 – 5 being R 2,360,800, R 2,930,158, R... , M.Tech. (Chemical Engineering)
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Performance and emission evaluation of a bi-fuel car
- Authors: Kukoyi, Temitope Oladayo
- Date: 2016
- Subjects: Alternative fuel vehicles , Spark ignition engines - Alternative fuels , Motor fuels , Biogas , Renewable energy sources
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/242306 , uj:24988
- Description: M.Ing. (Mechanical Engineering) , Abstract: A fundamental shift towards alternative sources of energy particularly in the transport sector has led to the use of fuels such as liquefied petroleum gas and natural gas in spark ignition (SI) engines. However, these fuels retain the challenges associated with fossil fuels which are primarily their finite reserves and negative effects on the ecosystem. This study assesses the use of biogas, a renewable and environmentally friendly high octane fuel in the more popular spark ignition powered passenger vehicle using the simplest single-point fuel delivery conversion kit available on the market. The vehicle powered by a 1.5 litre 1UF-ZE spark ignition engine was converted to a bi-fuel vehicle. Torque, power, and transient emissions were measured with a single roller chassis dynamometer and a gas analyser while running on vehicle quality biogas also referred to as biomethane. The data collated from the use of biogas was pitched with that of petrol in the same system to compare performance and tailpipe emissions. The biogas was simulated by mixing 95% methane (CH4) with 5% carbon dioxide (CO2). The experiments also afforded the opportunity to validate biogas similarity with natural gas (CNG) when used to power vehicles. The research further looked into enhancing system efficiency by investigating the addition of a measure of 2% hydrogen to create a biomethane-hydrogen mix (HCBG) which is within allowable limits of the mix used in a conventional spark ignition (SI) system to curb the negative impacts associated with hydrogen use as a fuel in internal combustion engines. The HCBG was derived by mixing 93% CH4 with 5% CO2 and 2% H2. Biogas recorded a reduction of 16% in maximum power and torque values when pitched with petrol while similar maximum power and torque values to that of biogas were derived from the experiments using natural gas to power the same vehicle. When the hydrogen-biomethane mix was utilised, a 1% power drop was noticed. However, slight increments in power and torque values at mid-speed ranges showed promise for higher hydrogen concentrations in the HCBG in fine-tuned systems. With respect to the mass emission of pollutants, the Inspection and Maintenance 240 (IM240) Drive Cycle was employed to determine the carbon dioxide (CO2), carbon monoxide(CO), hydrocarbon (HC), nitrous oxide (NOx) values in grammes per kilometer (g/km). Biogas recorded an 18% CO2 emission reduction compared to the data obtained using petrol (152.2 g/km). With reference to biogas, CNG recorded 0.4 g/km more CO2 mass emissions while the enhanced HCBG...
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- Authors: Kukoyi, Temitope Oladayo
- Date: 2016
- Subjects: Alternative fuel vehicles , Spark ignition engines - Alternative fuels , Motor fuels , Biogas , Renewable energy sources
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/242306 , uj:24988
- Description: M.Ing. (Mechanical Engineering) , Abstract: A fundamental shift towards alternative sources of energy particularly in the transport sector has led to the use of fuels such as liquefied petroleum gas and natural gas in spark ignition (SI) engines. However, these fuels retain the challenges associated with fossil fuels which are primarily their finite reserves and negative effects on the ecosystem. This study assesses the use of biogas, a renewable and environmentally friendly high octane fuel in the more popular spark ignition powered passenger vehicle using the simplest single-point fuel delivery conversion kit available on the market. The vehicle powered by a 1.5 litre 1UF-ZE spark ignition engine was converted to a bi-fuel vehicle. Torque, power, and transient emissions were measured with a single roller chassis dynamometer and a gas analyser while running on vehicle quality biogas also referred to as biomethane. The data collated from the use of biogas was pitched with that of petrol in the same system to compare performance and tailpipe emissions. The biogas was simulated by mixing 95% methane (CH4) with 5% carbon dioxide (CO2). The experiments also afforded the opportunity to validate biogas similarity with natural gas (CNG) when used to power vehicles. The research further looked into enhancing system efficiency by investigating the addition of a measure of 2% hydrogen to create a biomethane-hydrogen mix (HCBG) which is within allowable limits of the mix used in a conventional spark ignition (SI) system to curb the negative impacts associated with hydrogen use as a fuel in internal combustion engines. The HCBG was derived by mixing 93% CH4 with 5% CO2 and 2% H2. Biogas recorded a reduction of 16% in maximum power and torque values when pitched with petrol while similar maximum power and torque values to that of biogas were derived from the experiments using natural gas to power the same vehicle. When the hydrogen-biomethane mix was utilised, a 1% power drop was noticed. However, slight increments in power and torque values at mid-speed ranges showed promise for higher hydrogen concentrations in the HCBG in fine-tuned systems. With respect to the mass emission of pollutants, the Inspection and Maintenance 240 (IM240) Drive Cycle was employed to determine the carbon dioxide (CO2), carbon monoxide(CO), hydrocarbon (HC), nitrous oxide (NOx) values in grammes per kilometer (g/km). Biogas recorded an 18% CO2 emission reduction compared to the data obtained using petrol (152.2 g/km). With reference to biogas, CNG recorded 0.4 g/km more CO2 mass emissions while the enhanced HCBG...
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Parametric study of single and double stage membrane configuration in methane enrichment process
- Masebinu, S. O., Aboyade, A. O., Muzenda, E.
- Authors: Masebinu, S. O. , Aboyade, A. O. , Muzenda, E.
- Date: 2014
- Subjects: Biogas , Methane enrichment , Membrane configuration
- Type: Article
- Identifier: uj:5003 , http://hdl.handle.net/10210/13143
- Description: Operational study of a biogas upgrading plant with cleaning and methane (CH4) enrichment has been presented in this study. Parametric study was conducted to investigate the effect of variation of process conditions for single stage without recycle (SSWR) and double stage with permeate recycle (DSPR) on product purity, CH4 recovery and compression power requirement. In the study, achieving high CH4 recovery and product purity simultaneously could not be attained in SSWR configuration. The performance of DSPR yielded a better result but with higher membrane area and compression power. DSPR configuration achieved high CH4 recovery and purity at increasing feed pressure, selectivity and feed flow. The CH4 losses increased in both configurations as %CO2 increased in the feed. DSPR configuration is considered the best configuration due to the end use of the product, as vehicular fuel, which requires high product purity.
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- Authors: Masebinu, S. O. , Aboyade, A. O. , Muzenda, E.
- Date: 2014
- Subjects: Biogas , Methane enrichment , Membrane configuration
- Type: Article
- Identifier: uj:5003 , http://hdl.handle.net/10210/13143
- Description: Operational study of a biogas upgrading plant with cleaning and methane (CH4) enrichment has been presented in this study. Parametric study was conducted to investigate the effect of variation of process conditions for single stage without recycle (SSWR) and double stage with permeate recycle (DSPR) on product purity, CH4 recovery and compression power requirement. In the study, achieving high CH4 recovery and product purity simultaneously could not be attained in SSWR configuration. The performance of DSPR yielded a better result but with higher membrane area and compression power. DSPR configuration achieved high CH4 recovery and purity at increasing feed pressure, selectivity and feed flow. The CH4 losses increased in both configurations as %CO2 increased in the feed. DSPR configuration is considered the best configuration due to the end use of the product, as vehicular fuel, which requires high product purity.
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Enrichment of biogas for use as vehicular fuel: a review of the upgrading techniques
- Masebinu, S. O., Aboyade, A., Muzenda, Edison
- Authors: Masebinu, S. O. , Aboyade, A. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Biogas enrichment
- Type: Article
- Identifier: uj:4912 , ISSN 2349-1442 , http://hdl.handle.net/10210/13012
- Description: Biogas, a renewable energy, can be captured, upgraded and used to fuel a vehicle as an alternative to fossil fuel, thus, reducing greenhouse gas emission. Biogas is environmentally hazardous if emitted directly into the environment. Increasing demand for bio-methane to be used as vehicular fuel has called for efficient use of waste and technology that is optimal yet economical. Biogas in its raw state contains impurities that reduce its heating value to be used directly as fuel, hence, a need to enhance it by upgrading to bio-methane. Several techniques exist for upgrading biogas to bio-methane. This paper present four upgrading techniques; absorption, adsorption, membrane and cryogenic techniques, a brief theoretical background, advantages and operational issues associated with each technique.
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- Authors: Masebinu, S. O. , Aboyade, A. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Biogas enrichment
- Type: Article
- Identifier: uj:4912 , ISSN 2349-1442 , http://hdl.handle.net/10210/13012
- Description: Biogas, a renewable energy, can be captured, upgraded and used to fuel a vehicle as an alternative to fossil fuel, thus, reducing greenhouse gas emission. Biogas is environmentally hazardous if emitted directly into the environment. Increasing demand for bio-methane to be used as vehicular fuel has called for efficient use of waste and technology that is optimal yet economical. Biogas in its raw state contains impurities that reduce its heating value to be used directly as fuel, hence, a need to enhance it by upgrading to bio-methane. Several techniques exist for upgrading biogas to bio-methane. This paper present four upgrading techniques; absorption, adsorption, membrane and cryogenic techniques, a brief theoretical background, advantages and operational issues associated with each technique.
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A review of biogas production optimization from grass silage
- Muzenda, Edison, Sibiya, Noxolo
- Authors: Muzenda, Edison , Sibiya, Noxolo
- Date: 2014
- Subjects: Biogas , Grass - Silage , Anaerobic digestion
- Type: Article
- Identifier: uj:5033 , http://hdl.handle.net/10210/13553
- Description: Anaerobic digestion (AD) of organic materials offers an alternative source of renewable energy, as bio-methane has a potential to replace fossil fuels for energy production for heat and power, vehicular fuel and as well as valuable material recovery. In addition AD can address pollution problems by minimizing and utilizing biodegradable waste. This is a well-researched and technologically advanced technique with various successful small to large scale plants in the developed world. For developing countries, not much success has been reported due to operational and maintenance challenges, low biogas production and public perceptions among other several contributing factors. This paper reviews AD process optimization focusing on parameters such as temperature, pH, loading rate, hydraulic retention time and agitation. Several studies have shown optimum biogas production from grass in mesophilic, alkaline or neutral conditions at retention times of about 30 days. This review is the background and basis of our current work on optimizing biogas production from selected South African grass species.
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- Authors: Muzenda, Edison , Sibiya, Noxolo
- Date: 2014
- Subjects: Biogas , Grass - Silage , Anaerobic digestion
- Type: Article
- Identifier: uj:5033 , http://hdl.handle.net/10210/13553
- Description: Anaerobic digestion (AD) of organic materials offers an alternative source of renewable energy, as bio-methane has a potential to replace fossil fuels for energy production for heat and power, vehicular fuel and as well as valuable material recovery. In addition AD can address pollution problems by minimizing and utilizing biodegradable waste. This is a well-researched and technologically advanced technique with various successful small to large scale plants in the developed world. For developing countries, not much success has been reported due to operational and maintenance challenges, low biogas production and public perceptions among other several contributing factors. This paper reviews AD process optimization focusing on parameters such as temperature, pH, loading rate, hydraulic retention time and agitation. Several studies have shown optimum biogas production from grass in mesophilic, alkaline or neutral conditions at retention times of about 30 days. This review is the background and basis of our current work on optimizing biogas production from selected South African grass species.
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Bio-methane potential of the organic fraction of municipal solid waste
- Mojapelo, N., Muzenda, Edison, Kigozi, R., Aboyade, A. O.
- Authors: Mojapelo, N. , Muzenda, Edison , Kigozi, R. , Aboyade, A. O.
- Date: 2014
- Subjects: Biogas , Bio-methane , Municipal solid waste
- Type: Article
- Identifier: uj:5022 , http://hdl.handle.net/10210/13165
- Description: Biogas is a gas formed from the breakdown of biomass by microorganisms in an anaerobic environment composed of methane (50%–70%) and carbon dioxide (30%–50%). The upgrading of biogas by the removal of carbon dioxide to increase the percentage of methane to over 92% produces bio-methane which is a potent versatile clean fuel. This paper represents a study that was carried out at the University of Johannesburg’s Doornfontein Campus (UJ DFC) to ascertain the potential of bio-methane recovery from the organic fraction of municipal solid waste (OFMSW) collected at the campus’ cafeteria and student residences. ...
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- Authors: Mojapelo, N. , Muzenda, Edison , Kigozi, R. , Aboyade, A. O.
- Date: 2014
- Subjects: Biogas , Bio-methane , Municipal solid waste
- Type: Article
- Identifier: uj:5022 , http://hdl.handle.net/10210/13165
- Description: Biogas is a gas formed from the breakdown of biomass by microorganisms in an anaerobic environment composed of methane (50%–70%) and carbon dioxide (30%–50%). The upgrading of biogas by the removal of carbon dioxide to increase the percentage of methane to over 92% produces bio-methane which is a potent versatile clean fuel. This paper represents a study that was carried out at the University of Johannesburg’s Doornfontein Campus (UJ DFC) to ascertain the potential of bio-methane recovery from the organic fraction of municipal solid waste (OFMSW) collected at the campus’ cafeteria and student residences. ...
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Influence of digestate recirculation and recirculation percentage on biogas production from lawn grass via anaerobic digestion
- Sibiya, Noxolo T., Tesfagiorgis, Habtom B., Muzenda, Edison
- Authors: Sibiya, Noxolo T. , Tesfagiorgis, Habtom B. , Muzenda, Edison
- Date: 2015
- Subjects: Biogas , Digestate , Recirculation
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72893 , uj:18343 , Citation: Sibiya, N.T., Tesfagiorgis, H.B. & Muzenda, E. 2015. Influence of digestate recirculation and recirculation percentage on biogas production from lawn grass via anaerobic digestion.
- Description: Abstract: Recirculation of digestate either in the form of liquid or solids has proven to enhance biogas production from energy crops including lawn grass. The explanation to this is that digestate contains suitable bacteria and trace elements (nutrients) needed by methanogens. Influence of digestate recirculation and recirculation percentage in biogas production from lawn grass via anaerobic digestion was studied in laboratory scale digester (1L plastic bottles) at mesophilic condition. Three scenarios were used: digester without recycle digestate (control) (WRD), digesters with recycled liquid digestate (RLD) and digesters with recycled solid digestate (RSD). Liquid recycled digestate was added in percentages variation ranging from 10%-60%, solid recycle digestate was added in percentages variation ranging from 10%-50%. The maximum biogas production with methane content of 55% was obtained in the digester with 60% RLD on the 8th day. During the study of recirculation of solids, highest biogas yield with methane content of 53% was observed in a digester with RSD of 40% on the 5th day. Retention time for both digesters with recycled digestate was reduced and biogas production rate was increased compared to the digester with no recycled digestate.
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- Authors: Sibiya, Noxolo T. , Tesfagiorgis, Habtom B. , Muzenda, Edison
- Date: 2015
- Subjects: Biogas , Digestate , Recirculation
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72893 , uj:18343 , Citation: Sibiya, N.T., Tesfagiorgis, H.B. & Muzenda, E. 2015. Influence of digestate recirculation and recirculation percentage on biogas production from lawn grass via anaerobic digestion.
- Description: Abstract: Recirculation of digestate either in the form of liquid or solids has proven to enhance biogas production from energy crops including lawn grass. The explanation to this is that digestate contains suitable bacteria and trace elements (nutrients) needed by methanogens. Influence of digestate recirculation and recirculation percentage in biogas production from lawn grass via anaerobic digestion was studied in laboratory scale digester (1L plastic bottles) at mesophilic condition. Three scenarios were used: digester without recycle digestate (control) (WRD), digesters with recycled liquid digestate (RLD) and digesters with recycled solid digestate (RSD). Liquid recycled digestate was added in percentages variation ranging from 10%-60%, solid recycle digestate was added in percentages variation ranging from 10%-50%. The maximum biogas production with methane content of 55% was obtained in the digester with 60% RLD on the 8th day. During the study of recirculation of solids, highest biogas yield with methane content of 53% was observed in a digester with RSD of 40% on the 5th day. Retention time for both digesters with recycled digestate was reduced and biogas production rate was increased compared to the digester with no recycled digestate.
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Biogas production from anaerobic digestion of fruit and vegetable waste from Johannesburg market
- Maile, Ireen, Muzenda, Edison, Mbohwa, Charles
- Authors: Maile, Ireen , Muzenda, Edison , Mbohwa, Charles
- Date: 2016
- Subjects: Biogas , Fruits and vegetables , Microbes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217553 , uj:21654 , Citation: Maile, I., Muzenda, E. & Mbohwa, C. 2016. Biogas production from anaerobic digestion of fruit and vegetable waste from Johannesburg market.
- Description: Abstract: Biogas production from anaerobic digestion is a promising technology for sustainable energy development. Biochemical methane potential (BMP) tests are normally run to determine the possible methane that can be obtained from each biomass. The aim of this study is to determine the biochemical potential of fruits and vegetable wastes from the Johannesburg market. The biochemical methane potential tests were carried out using the bioprocess control Automatic Methane Potential Test System (AMPTS) II machine. The initial pH of the feedstock was low during the preparation of the feed since fruits and vegetable waste (FVW) are acidic and thus buffer solutions were used to increase the pH to 6.5-7.5. The BMP for the FVW was determined to be on average 300 ml CH4 /g VS added with methane content between 50-60 % volume.
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- Authors: Maile, Ireen , Muzenda, Edison , Mbohwa, Charles
- Date: 2016
- Subjects: Biogas , Fruits and vegetables , Microbes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217553 , uj:21654 , Citation: Maile, I., Muzenda, E. & Mbohwa, C. 2016. Biogas production from anaerobic digestion of fruit and vegetable waste from Johannesburg market.
- Description: Abstract: Biogas production from anaerobic digestion is a promising technology for sustainable energy development. Biochemical methane potential (BMP) tests are normally run to determine the possible methane that can be obtained from each biomass. The aim of this study is to determine the biochemical potential of fruits and vegetable wastes from the Johannesburg market. The biochemical methane potential tests were carried out using the bioprocess control Automatic Methane Potential Test System (AMPTS) II machine. The initial pH of the feedstock was low during the preparation of the feed since fruits and vegetable waste (FVW) are acidic and thus buffer solutions were used to increase the pH to 6.5-7.5. The BMP for the FVW was determined to be on average 300 ml CH4 /g VS added with methane content between 50-60 % volume.
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Technology selection and siting of a biogas plant for OFMSW via multi-criteria decision analysis
- Kigozi, R., Aboyade, A. O., Muzenda, E.
- Authors: Kigozi, R. , Aboyade, A. O. , Muzenda, E.
- Date: 2015
- Subjects: Biogas , Digester gas , Municipal solid waste
- Language: English
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/384643 , http://hdl.handle.net/10210/56250 , uj:16347 , Citation: Kigozi, R., Muzenda, E. & Aboyade, A. 2015. Technology selection and siting of a biogas plant for OFMSW via multi-criteria decision analysis. South African Journal of Chemical Engineering, 20(1):1-15 , ISSN:1026-9185
- Description: Abstract: Multi-criteria decision analysis (MCDA) techniques were applied to choose a biogas digester technology and a site from a list of potential alternatives for an anaerobic digestion (AD) system utilising the organic fraction of municipal solid waste (OFMSW) based on a case study at the University of Johannesburg’s Doornfontein campus in South Africa. The simple multi-attribute rating technique (SMART) and analytic hierarchy process (AHP) techniques of MCDA were used to select a suitable biodigester model and site respectively. From a list of 14 biodigester technologies to be established at 1 of 3 potential sites in the study area, the most preferred model was the Puxin digester to be sited near the Aurum ladies’ residence within the school campus to supply biogas for heating purposes.
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- Authors: Kigozi, R. , Aboyade, A. O. , Muzenda, E.
- Date: 2015
- Subjects: Biogas , Digester gas , Municipal solid waste
- Language: English
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/384643 , http://hdl.handle.net/10210/56250 , uj:16347 , Citation: Kigozi, R., Muzenda, E. & Aboyade, A. 2015. Technology selection and siting of a biogas plant for OFMSW via multi-criteria decision analysis. South African Journal of Chemical Engineering, 20(1):1-15 , ISSN:1026-9185
- Description: Abstract: Multi-criteria decision analysis (MCDA) techniques were applied to choose a biogas digester technology and a site from a list of potential alternatives for an anaerobic digestion (AD) system utilising the organic fraction of municipal solid waste (OFMSW) based on a case study at the University of Johannesburg’s Doornfontein campus in South Africa. The simple multi-attribute rating technique (SMART) and analytic hierarchy process (AHP) techniques of MCDA were used to select a suitable biodigester model and site respectively. From a list of 14 biodigester technologies to be established at 1 of 3 potential sites in the study area, the most preferred model was the Puxin digester to be sited near the Aurum ladies’ residence within the school campus to supply biogas for heating purposes.
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Investigating the potential of generating electrical energy from digester carbon waste sources at ERWAT waste water treatment facilities in the Ekurhuleni District Municipality
- Authors: Mabaso, Thembeka
- Date: 2017
- Subjects: Biogas , Digester gas , Sewage sludge fuel , Sewage - Purification - Anaerobic treatment , Sewage disposal plants - South Africa - Ekurhuleni
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/271340 , uj:28857
- Description: M.Sc. (Environmental Management) , Abstract: Biogas, a renewable energy source, is generated from biomass under anaerobic treatment. Anaerobic treatment of biomass, which is usually sludge at the stage of anaerobic digestion, occurs within a vessel – also known as a digester – enclosed of air and usually has bacteria derived from the incoming waste for digestion and the production of biogas. The main objective of this study was to investigate the electrical energy potential from digester carbon waste sources utilizing analyses from the gas and a basic excel software model. For this purpose, we used selected wastewater treatment facilities of the East Rand Water Care Company (ERWAT) that had gas reservoirs and sampling points available. The GIZ/WEC model was utilized together with other WWTP-based parameters to calculate potential electricity that could be generated daily in two plants (Vlakplaats and Waterval). The size of combined heat and power (CHP) suitable for each of the WWTPs to generate power from the biogas generated was also estimated. We found four components in the biogas (CH4, CO2, traces of H2S and O2) with CH4 and CO2 being the main constituents. The concentrations of these main constituents were 30%-38% and 63%-70% for CO2 and CH4, respectively. The potential electricity calculated was on average 3 861 kWeh/day for the Vlakplaats plant and 21 777 kWeh/day for Waterval. These values change as the biogas production varies depending on the operational conditions. This study shows that future generation of electricity using biogas is achievable at these plants. Although this study is not new it clearly emphasizes the potential of biogas utilization as a cost saving incentive at the plants where analysis was conducted.
- Full Text:
- Authors: Mabaso, Thembeka
- Date: 2017
- Subjects: Biogas , Digester gas , Sewage sludge fuel , Sewage - Purification - Anaerobic treatment , Sewage disposal plants - South Africa - Ekurhuleni
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/271340 , uj:28857
- Description: M.Sc. (Environmental Management) , Abstract: Biogas, a renewable energy source, is generated from biomass under anaerobic treatment. Anaerobic treatment of biomass, which is usually sludge at the stage of anaerobic digestion, occurs within a vessel – also known as a digester – enclosed of air and usually has bacteria derived from the incoming waste for digestion and the production of biogas. The main objective of this study was to investigate the electrical energy potential from digester carbon waste sources utilizing analyses from the gas and a basic excel software model. For this purpose, we used selected wastewater treatment facilities of the East Rand Water Care Company (ERWAT) that had gas reservoirs and sampling points available. The GIZ/WEC model was utilized together with other WWTP-based parameters to calculate potential electricity that could be generated daily in two plants (Vlakplaats and Waterval). The size of combined heat and power (CHP) suitable for each of the WWTPs to generate power from the biogas generated was also estimated. We found four components in the biogas (CH4, CO2, traces of H2S and O2) with CH4 and CO2 being the main constituents. The concentrations of these main constituents were 30%-38% and 63%-70% for CO2 and CH4, respectively. The potential electricity calculated was on average 3 861 kWeh/day for the Vlakplaats plant and 21 777 kWeh/day for Waterval. These values change as the biogas production varies depending on the operational conditions. This study shows that future generation of electricity using biogas is achievable at these plants. Although this study is not new it clearly emphasizes the potential of biogas utilization as a cost saving incentive at the plants where analysis was conducted.
- Full Text:
Municipal solid waste utilisation for green energy in Gauteng province - South Africa : a review
- Pilusa, Tsietsi J., Muzenda, Edison
- Authors: Pilusa, Tsietsi J. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Solid waste management - South Africa - Johannesburg , Green energy
- Type: Article
- Identifier: uj:4958 , http://hdl.handle.net/10210/13059
- Description: This short paper discusses the potential of utilizing various municipal solids waste streams as feed stock for green energy production. These waste streams includes but not limited to mixed combustible waste, rubber and plastic waste, health care risk waste, organic biodegradable waste, biomass and sewage sludge. Technologies such as anaerobic digestion, gasification and pyrolysis have been reviewed relative to the location and waste stream quantities in the selected sample area. It was discovered that there are environmental, social and economic benefits in waste to energy approach for the waste streams reviewed. The feasibility of implementing such technologies is mainly dependent on the initial capital investment and operational cost of the facility. Other factors include the size of the waste stream, product price and demand.
- Full Text:
- Authors: Pilusa, Tsietsi J. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Solid waste management - South Africa - Johannesburg , Green energy
- Type: Article
- Identifier: uj:4958 , http://hdl.handle.net/10210/13059
- Description: This short paper discusses the potential of utilizing various municipal solids waste streams as feed stock for green energy production. These waste streams includes but not limited to mixed combustible waste, rubber and plastic waste, health care risk waste, organic biodegradable waste, biomass and sewage sludge. Technologies such as anaerobic digestion, gasification and pyrolysis have been reviewed relative to the location and waste stream quantities in the selected sample area. It was discovered that there are environmental, social and economic benefits in waste to energy approach for the waste streams reviewed. The feasibility of implementing such technologies is mainly dependent on the initial capital investment and operational cost of the facility. Other factors include the size of the waste stream, product price and demand.
- Full Text:
Life cycle assessment of a biogas digester : case study of a South African system
- Authors: Madushele, Nkosinathi
- Date: 2018
- Subjects: Biogas , Product life cycle - Environmental aspects , Greenhouse gases - Environmental aspects , Biomass gasification
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/263076 , uj:27804
- Description: D.Ing. (Mechanical Engineering Sciences) , Abstract: Sustainable energy is a huge point of discussion amongst policy makers and academics alike. This stems from an increase in the world’s population, with shrinking finite energy sources that are currently used. The University of Johannesburg seeks to address this challenge through the development of a biogas digester plant. The study analysed a gate to gate model of a domestic biogas digester, with the intention of both evaluating the environmental impact of the University’s biogas digester, while also making use of fundamental computations in performing a Life Cycle Assessment initiative, as opposed to using commercially available software. This was done in the hopes of gaining deeper understanding on the computational structure of Life Cycle Assessments, and this can then be translated to developing more region specific databases for future studies. It was found that the designed digester produces more greenhouse gases (GHGs) during operation, than when the digester is manufactured and commissioned. This enabled a design alteration that minimised the GHGs prior to the completion of the design. Amongst a number of environmental impacts investigated, it is interesting to note that during the operational stage of the digester, there are chemicals that contribute to photochemical ozone depletion, and that in turn resulted in the recommendation of revising mechanical equipment that was initially proposed by the designer.
- Full Text:
- Authors: Madushele, Nkosinathi
- Date: 2018
- Subjects: Biogas , Product life cycle - Environmental aspects , Greenhouse gases - Environmental aspects , Biomass gasification
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/263076 , uj:27804
- Description: D.Ing. (Mechanical Engineering Sciences) , Abstract: Sustainable energy is a huge point of discussion amongst policy makers and academics alike. This stems from an increase in the world’s population, with shrinking finite energy sources that are currently used. The University of Johannesburg seeks to address this challenge through the development of a biogas digester plant. The study analysed a gate to gate model of a domestic biogas digester, with the intention of both evaluating the environmental impact of the University’s biogas digester, while also making use of fundamental computations in performing a Life Cycle Assessment initiative, as opposed to using commercially available software. This was done in the hopes of gaining deeper understanding on the computational structure of Life Cycle Assessments, and this can then be translated to developing more region specific databases for future studies. It was found that the designed digester produces more greenhouse gases (GHGs) during operation, than when the digester is manufactured and commissioned. This enabled a design alteration that minimised the GHGs prior to the completion of the design. Amongst a number of environmental impacts investigated, it is interesting to note that during the operational stage of the digester, there are chemicals that contribute to photochemical ozone depletion, and that in turn resulted in the recommendation of revising mechanical equipment that was initially proposed by the designer.
- Full Text:
Biogas upgrade to biomethane from landfill wastes : a review
- Dada, Opeoluwa, Mbohwa, Charles
- Authors: Dada, Opeoluwa , Mbohwa, Charles
- Date: 2017
- Subjects: Biofuel , Biogas , Biomethane , Landfill gases - Recycling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/218654 , uj:21802 , Citation: Dada, O. & Mbohwa, C. 2017. Biogas upgrade to biomethane from landfill wastes : a review. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park.
- Description: Abstract: Wastes from landfills originate from many spheres of life. These wastes are produced as a result of human activities either domestically or industrially. Wastes are generally regarded as by-products nevertheless; they could be useful resources in wrong hands or location. Due to the fact that biogas could be produced from two main sources such as landfills and digesters chambers [1]. It is important to critically look into the biodegradable materials that ends up as wastes on our landfills because they could be converted into biogas as a result of the high concentration of carbon and hydrogen contained in such wastes and majority of which are from agricultural and domestic locations. Recently, producing biogas is not good enough for some applications therefore the need to upgrade it for usage as a vehicular fuel [2]. This paper reviews landfill waste categorization, biogas production processes, biogas to biomethane upgrade, and biomethane utilization.
- Full Text:
- Authors: Dada, Opeoluwa , Mbohwa, Charles
- Date: 2017
- Subjects: Biofuel , Biogas , Biomethane , Landfill gases - Recycling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/218654 , uj:21802 , Citation: Dada, O. & Mbohwa, C. 2017. Biogas upgrade to biomethane from landfill wastes : a review. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park.
- Description: Abstract: Wastes from landfills originate from many spheres of life. These wastes are produced as a result of human activities either domestically or industrially. Wastes are generally regarded as by-products nevertheless; they could be useful resources in wrong hands or location. Due to the fact that biogas could be produced from two main sources such as landfills and digesters chambers [1]. It is important to critically look into the biodegradable materials that ends up as wastes on our landfills because they could be converted into biogas as a result of the high concentration of carbon and hydrogen contained in such wastes and majority of which are from agricultural and domestic locations. Recently, producing biogas is not good enough for some applications therefore the need to upgrade it for usage as a vehicular fuel [2]. This paper reviews landfill waste categorization, biogas production processes, biogas to biomethane upgrade, and biomethane utilization.
- Full Text:
Bio-methane generation from organic waste : a review
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Anaerobic digestion , Biodegradable material , Biogas
- Type: Article
- Identifier: uj:4987 , ISSN 2078-0966 , http://hdl.handle.net/10210/13119
- Description: Anaerobic digestion of organic waste can address both energy recovery and pollution control. A variety of agricultural, industrial and domestic wastes can be anaerobically digested as they contain easily biodegradable material. Biogas contains 50 -70% methane and 30-50% carbon dioxide as well as small a amounts of other gases with calorific value of about 21-24 MJ/m3. This paper reviews the history of biogas, biogas production stages and operating parameters. The anaerobic digestion configuration and potential substrates for biogas production are also considered.
- Full Text:
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Anaerobic digestion , Biodegradable material , Biogas
- Type: Article
- Identifier: uj:4987 , ISSN 2078-0966 , http://hdl.handle.net/10210/13119
- Description: Anaerobic digestion of organic waste can address both energy recovery and pollution control. A variety of agricultural, industrial and domestic wastes can be anaerobically digested as they contain easily biodegradable material. Biogas contains 50 -70% methane and 30-50% carbon dioxide as well as small a amounts of other gases with calorific value of about 21-24 MJ/m3. This paper reviews the history of biogas, biogas production stages and operating parameters. The anaerobic digestion configuration and potential substrates for biogas production are also considered.
- Full Text:
A case for biogas as the viable substitute fuel in spark ignition engines
- Kukoyi, T. O., Muzenda. E., Mbohwa, Charles
- Authors: Kukoyi, T. O. , Muzenda. E. , Mbohwa, Charles
- Date: 2017
- Subjects: Biogas , Crude Oil , Fossil fuels
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250381 , uj:26091 , Citation: Kukoyi, T.O., Muzenda. E. & Mbohwa, C. 2017. A case for biogas as the viable substitute fuel in spark ignition engines.
- Description: Abstract: Unstable prices, energy security, depleting reserves and their negative effect on the ecosystem have forced mankind to critically tackle it’s over dependence on fossil fuels. Fossil fuels are oil coal and natural gas which currently caters for over 80% of the world’s energy needs. Crude oil derivatives and coal have been extensively tapped and utilized to make living more comfortable and to drive different sectors that power the world’s economies. These have however come at an irreparable cost on human health and the environment. The transport sector, a major driver of development consumes the 2nd largest portion of our fossil energy reserves and has also been at the forefront of the creation of alternative fuels to mitigate various economic, political and environmental challenges associated with the refining and utilization of the conventional fuels in the sector which are petrol and diesel. The sector recently turned to natural gas as an efficient substitute particularly in the more popular passenger cars that utilize spark ignition engines. It performs excellently with lesser tail pipe emissions when compared with petrol which emits lesser harmful products than diesel. Though readily available, with well-developed infrastructure, its fossil nature makes it a finite resource hence the need for a viable renewable replacement fuel. Many alternative fuels have been developed to power the spark ignition engine as stricter emission standards are being created and the need for improved fuel economy with better system efficiency. This paper highlights the popular alternative fuels been utilized in spark ignition engines which are hydrogen, ethanol, liquefied petroleum gas and biogas looking at criteria such as performance, renewability, ease of integration into existing infrastructure and cost with the need to make a case for biogas as the right substitute for petrol in existing and future spark ignition engine applications.
- Full Text:
- Authors: Kukoyi, T. O. , Muzenda. E. , Mbohwa, Charles
- Date: 2017
- Subjects: Biogas , Crude Oil , Fossil fuels
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250381 , uj:26091 , Citation: Kukoyi, T.O., Muzenda. E. & Mbohwa, C. 2017. A case for biogas as the viable substitute fuel in spark ignition engines.
- Description: Abstract: Unstable prices, energy security, depleting reserves and their negative effect on the ecosystem have forced mankind to critically tackle it’s over dependence on fossil fuels. Fossil fuels are oil coal and natural gas which currently caters for over 80% of the world’s energy needs. Crude oil derivatives and coal have been extensively tapped and utilized to make living more comfortable and to drive different sectors that power the world’s economies. These have however come at an irreparable cost on human health and the environment. The transport sector, a major driver of development consumes the 2nd largest portion of our fossil energy reserves and has also been at the forefront of the creation of alternative fuels to mitigate various economic, political and environmental challenges associated with the refining and utilization of the conventional fuels in the sector which are petrol and diesel. The sector recently turned to natural gas as an efficient substitute particularly in the more popular passenger cars that utilize spark ignition engines. It performs excellently with lesser tail pipe emissions when compared with petrol which emits lesser harmful products than diesel. Though readily available, with well-developed infrastructure, its fossil nature makes it a finite resource hence the need for a viable renewable replacement fuel. Many alternative fuels have been developed to power the spark ignition engine as stricter emission standards are being created and the need for improved fuel economy with better system efficiency. This paper highlights the popular alternative fuels been utilized in spark ignition engines which are hydrogen, ethanol, liquefied petroleum gas and biogas looking at criteria such as performance, renewability, ease of integration into existing infrastructure and cost with the need to make a case for biogas as the right substitute for petrol in existing and future spark ignition engine applications.
- Full Text:
Optimising biogas production from anaerobic co-digestion of chicken manure and organic fraction of municipal solid waste
- Matheri, A. N., Ndiweni, S. N., Belaid, M., Muzenda, E., Hubert, R.
- Authors: Matheri, A. N. , Ndiweni, S. N. , Belaid, M. , Muzenda, E. , Hubert, R.
- Date: 2017
- Subjects: Anaerobic , Biogas , Co-digestion
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/241017 , uj:24803 , Citation: Matheri, A.N. et al. 2017. Optimising biogas production from anaerobic co-digestion of chicken manure and organic fraction of municipal solid waste.
- Description: Abstract: In this study, it was observed that in experimental work under laboratory scale using conventional biochemical methane potential (BMP) assay, the loading rate ratio 4:1 had optimum biodegradability rate than other ratios which were investigated, while the loading rate ratio of 1:1 had optimum biogas and methane yield after 15 days hydraulic retention time. It was concluded that chicken waste (CM) monodigestion has higher biodegradability rate compare to organic fraction municipality solid waste (OFMSW) mono-digestion. Co-digestion of OFMSW and CM stabilizes conditions in digestion process such as carbon to nitrogen (C:N) ratio in the substrate mixtures as well as macro and micronutrients, pH, inhibitors or toxic compounds, dry matter and thus increasing biogas production. It was concluded that the organic waste generated in the municipal landfills could be co-digested with CM to produce methane which can be used as a source of environmentally friendly and clean energy for the transport sector, industries and residential homes.
- Full Text:
- Authors: Matheri, A. N. , Ndiweni, S. N. , Belaid, M. , Muzenda, E. , Hubert, R.
- Date: 2017
- Subjects: Anaerobic , Biogas , Co-digestion
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/241017 , uj:24803 , Citation: Matheri, A.N. et al. 2017. Optimising biogas production from anaerobic co-digestion of chicken manure and organic fraction of municipal solid waste.
- Description: Abstract: In this study, it was observed that in experimental work under laboratory scale using conventional biochemical methane potential (BMP) assay, the loading rate ratio 4:1 had optimum biodegradability rate than other ratios which were investigated, while the loading rate ratio of 1:1 had optimum biogas and methane yield after 15 days hydraulic retention time. It was concluded that chicken waste (CM) monodigestion has higher biodegradability rate compare to organic fraction municipality solid waste (OFMSW) mono-digestion. Co-digestion of OFMSW and CM stabilizes conditions in digestion process such as carbon to nitrogen (C:N) ratio in the substrate mixtures as well as macro and micronutrients, pH, inhibitors or toxic compounds, dry matter and thus increasing biogas production. It was concluded that the organic waste generated in the municipal landfills could be co-digested with CM to produce methane which can be used as a source of environmentally friendly and clean energy for the transport sector, industries and residential homes.
- Full Text:
Optimization of biogas production from City of Johannesburg market waste by anaerobic digestion for sustainable energy development
- Authors: Singh, Suraya
- Date: 2018
- Subjects: Biogas , Biomass energy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/295034 , uj:32113
- Description: M.Tech. (Chemical Engineering) , Abstract: Biogas, as a renewable energy source, is regarded as a viable alternative to the burning of fossil fuels to meet energy demands. The production of biogas to meet energy needs not only has environmental benefits such as reduction in greenhouse gas emissions and responsible waste disposal but also socio-economic benefits, especially when applied to a rural setting, such as improvements in employment, professional qualification and overall food supply of the local population. The main objective of this study was to determine optimum biogas production from City of Johannesburg (CoJ) market waste, composed primarily of fruit and vegetable waste (FVW), under anaerobic condition. The influence of operational factors such as temperature, pH, loading rate and retention time were evaluated. The co-digestion of FVW with cow dung (CD) at varying mixing ratios was also evaluated as a technique to optimize biogas production. Mono-digestion of FVW at thermophilic temperatures were optimum for both biogas and methane production. Changes in organic loading rate (OLR) indicated that with increases in OLR there were increases in both biogas and methane production. The highest biogas and methane production occurred for an OLR of FVW: 200g. The optimum retention time for biogas and methane production was determined to be 14 days and 10 days respectively. The explanation for the prolonged biogas and methane production has been accredited to the fact that there was a greater component of biodegradable material available for breakdown by methanogenic bacteria but even more critical than that was the alkaline pH of 7.18 of this substrate mixture at the commencement of digestion. However, experimental results indicated that co-digestion is the preferred method to optimize biogas and methane production. According to the experimental results obtained, a mixing ratio of FVW: CD of 20:40g is the optimum substrate mixture for both biogas and methane production. The optimum environmental conditions for co-digestion was found to be at 37°C with a pH range between 7.12 to 7.18, while the optimal retention time was found to be 33 days. It was found that when the mixing ratios contained between 50% and less cow dung with corresponding increases in FVW, there were drastic reductions in the digester stability and overall production rates for those substrate mixing ratios. It was therefore concluded that in order to ensure sustained and good biogas and methane production via co-digestion, the CD content should remain above 50% of the total mixture.
- Full Text:
- Authors: Singh, Suraya
- Date: 2018
- Subjects: Biogas , Biomass energy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/295034 , uj:32113
- Description: M.Tech. (Chemical Engineering) , Abstract: Biogas, as a renewable energy source, is regarded as a viable alternative to the burning of fossil fuels to meet energy demands. The production of biogas to meet energy needs not only has environmental benefits such as reduction in greenhouse gas emissions and responsible waste disposal but also socio-economic benefits, especially when applied to a rural setting, such as improvements in employment, professional qualification and overall food supply of the local population. The main objective of this study was to determine optimum biogas production from City of Johannesburg (CoJ) market waste, composed primarily of fruit and vegetable waste (FVW), under anaerobic condition. The influence of operational factors such as temperature, pH, loading rate and retention time were evaluated. The co-digestion of FVW with cow dung (CD) at varying mixing ratios was also evaluated as a technique to optimize biogas production. Mono-digestion of FVW at thermophilic temperatures were optimum for both biogas and methane production. Changes in organic loading rate (OLR) indicated that with increases in OLR there were increases in both biogas and methane production. The highest biogas and methane production occurred for an OLR of FVW: 200g. The optimum retention time for biogas and methane production was determined to be 14 days and 10 days respectively. The explanation for the prolonged biogas and methane production has been accredited to the fact that there was a greater component of biodegradable material available for breakdown by methanogenic bacteria but even more critical than that was the alkaline pH of 7.18 of this substrate mixture at the commencement of digestion. However, experimental results indicated that co-digestion is the preferred method to optimize biogas and methane production. According to the experimental results obtained, a mixing ratio of FVW: CD of 20:40g is the optimum substrate mixture for both biogas and methane production. The optimum environmental conditions for co-digestion was found to be at 37°C with a pH range between 7.12 to 7.18, while the optimal retention time was found to be 33 days. It was found that when the mixing ratios contained between 50% and less cow dung with corresponding increases in FVW, there were drastic reductions in the digester stability and overall production rates for those substrate mixing ratios. It was therefore concluded that in order to ensure sustained and good biogas and methane production via co-digestion, the CD content should remain above 50% of the total mixture.
- Full Text:
Mathematical modelling for biogas production
- Authors: Matheri, Anthony Njuguna
- Date: 2016
- Subjects: Sewage - Purification - Anaerobic treatment , Sewage - Purification - Mathematical models , Renewable energy sources , Biomass energy , Biogas
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/213006 , uj:21066
- Description: Abstract: The main focus of this dissertation is the experimental, modelling and simulation of anaerobic digestion processes from pilot bio-digesters. For this purpose, biochemical kinetic models were utilized together with corresponding simulation software; DYNOCHEM. By application of the anaerobic digestion (AD), different parameters have been investigated and simulated including adjustments of the process model and corresponding modifications. To validate the process model, the modelled data was compared with experimental monitored laboratory results. Bio-chemical kinetics modelling was applied as a systematic tool in order to support the process design and optimization of a demonstration of the biogas processes which constitutes the main scientific framework and background of this dissertation. Monitored laboratory-scale biogas production data were used for parameter calibration in order to predict plant performance. The calibration focused on the influent characterization of both substrates and on selection of kinetic of the coefficients in order to generate a uniform set of parameters which are applicable for the simulation of codigestion. In this study, it was observed that the experiment work under laboratory scale using conventional bio-methane potential (BMP) analyzers under mesophilic optimum temperature of 35 oC and 37 oC, and pH of 7 for co-digestion of organic fraction of municipal solid waste (OFMSW) with cow dung and manure with grass clippings. The substrate characterization moisture content ranged from 60-95%, volatile content 55-95%, total solid 10-90% and carbon to nitrogen ratio 16-20 for manure and 5-15 for OFMSW. All trace elements concentration were below the threshold of 32 mg/l that leads to inhibition of micro-organisms activity. The rate of conversion increased with retention time. According to the findings, 54-62% of methane composition was evaluated. The kinetics constant evaluated ranged from 0.009-0.35 d-1 and coefficient of determination (R2) ranged from 0.9989-0.9998. The Michaelis-Menten and Monod models provided goodness of fit of 0.9997 with confidential level of 95%. The simulations confirmed that the rate of conversion increased as temperature increases and conversion of reactants increased with retention time, until an equilibrium state was reached. The AD process modelling using DYNOCHEM was successfully modified and implemented to account for unsteady operation which is generally the case of full-scale reactor by developed methodology. , M.Tech. (Chemical Engineering)
- Full Text:
- Authors: Matheri, Anthony Njuguna
- Date: 2016
- Subjects: Sewage - Purification - Anaerobic treatment , Sewage - Purification - Mathematical models , Renewable energy sources , Biomass energy , Biogas
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/213006 , uj:21066
- Description: Abstract: The main focus of this dissertation is the experimental, modelling and simulation of anaerobic digestion processes from pilot bio-digesters. For this purpose, biochemical kinetic models were utilized together with corresponding simulation software; DYNOCHEM. By application of the anaerobic digestion (AD), different parameters have been investigated and simulated including adjustments of the process model and corresponding modifications. To validate the process model, the modelled data was compared with experimental monitored laboratory results. Bio-chemical kinetics modelling was applied as a systematic tool in order to support the process design and optimization of a demonstration of the biogas processes which constitutes the main scientific framework and background of this dissertation. Monitored laboratory-scale biogas production data were used for parameter calibration in order to predict plant performance. The calibration focused on the influent characterization of both substrates and on selection of kinetic of the coefficients in order to generate a uniform set of parameters which are applicable for the simulation of codigestion. In this study, it was observed that the experiment work under laboratory scale using conventional bio-methane potential (BMP) analyzers under mesophilic optimum temperature of 35 oC and 37 oC, and pH of 7 for co-digestion of organic fraction of municipal solid waste (OFMSW) with cow dung and manure with grass clippings. The substrate characterization moisture content ranged from 60-95%, volatile content 55-95%, total solid 10-90% and carbon to nitrogen ratio 16-20 for manure and 5-15 for OFMSW. All trace elements concentration were below the threshold of 32 mg/l that leads to inhibition of micro-organisms activity. The rate of conversion increased with retention time. According to the findings, 54-62% of methane composition was evaluated. The kinetics constant evaluated ranged from 0.009-0.35 d-1 and coefficient of determination (R2) ranged from 0.9989-0.9998. The Michaelis-Menten and Monod models provided goodness of fit of 0.9997 with confidential level of 95%. The simulations confirmed that the rate of conversion increased as temperature increases and conversion of reactants increased with retention time, until an equilibrium state was reached. The AD process modelling using DYNOCHEM was successfully modified and implemented to account for unsteady operation which is generally the case of full-scale reactor by developed methodology. , M.Tech. (Chemical Engineering)
- Full Text:
Effect of nutrient addition during anaerobic digestion of potato peels and maize husk
- Ramatsa, Ishmael, Sibiya, Noxolo, Huberts, Roberth
- Authors: Ramatsa, Ishmael , Sibiya, Noxolo , Huberts, Roberth
- Date: 2014
- Subjects: Anaerobic bacteria , Renewable energy sources , Biomass energy , Biogas
- Type: Article
- Identifier: uj:5091 , http://hdl.handle.net/10210/13681
- Description: The composition of the substrate and nutrients addition plays a very significant role during the production of the biogas. For this reason this paper tries to evaluate the effect of nutrients addition during biogas production under anaerobic conditions. Potato peels wastes and maize husk were anaerobically digested in a 5 liter scale reactor at mesophilic conditions (32 o C). The characteristics of the potato peels were and maize husk are presented in Table 1. The results obtained indicated that the addition of the nutrients during anaerobic digestion has an influence on the biogas production, meanwhile methane content in biogas varied from 48 to 64%.
- Full Text:
- Authors: Ramatsa, Ishmael , Sibiya, Noxolo , Huberts, Roberth
- Date: 2014
- Subjects: Anaerobic bacteria , Renewable energy sources , Biomass energy , Biogas
- Type: Article
- Identifier: uj:5091 , http://hdl.handle.net/10210/13681
- Description: The composition of the substrate and nutrients addition plays a very significant role during the production of the biogas. For this reason this paper tries to evaluate the effect of nutrients addition during biogas production under anaerobic conditions. Potato peels wastes and maize husk were anaerobically digested in a 5 liter scale reactor at mesophilic conditions (32 o C). The characteristics of the potato peels were and maize husk are presented in Table 1. The results obtained indicated that the addition of the nutrients during anaerobic digestion has an influence on the biogas production, meanwhile methane content in biogas varied from 48 to 64%.
- Full Text: