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Biogas production and its optimization for increase in methane yield

- Dada, Opeoluwa Rotimi

  • Authors: Dada, Opeoluwa Rotimi
  • Date: 2020
  • Subjects: Biogas , Methane
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/479468 , uj:43371
  • Description: Abstract: Production of energy from Municipal Solid Waste (MSW) is becoming a major concern for the government and private sectors in South Africa because of the drastic increase in the quantity of waste generated and its effect on the environment. Globally, the major source of energy generation has been fossil fuel which comprises of Coal, Petroleum and Natural Gas. Even though these natural given resources have helped in the development of the world to its present state these commodities have also contributed to the menace the world is experiencing since past decades especially in the aspect of environmental pollution, climate change, global warming and Greenhouse effects. Due to this, various research studies have been undertaken and some are still ongoing in order to see how we can create a sustainable environment whereby present needs are met yet not compromising the future of the forthcoming generations. In the quest for developing clean, renewable and sustainable energy, various resources are being looked at such as biomass, geothermal, wind, solar, hydropower, biofuels, landfill gas, pyrolysis amongst others. Nevertheless, due to daily increase in the quantity of waste produced in most municipalities there is a need to develop environmentally friendly and cost-effective techniques of managing MSW and produce biogas that can be upgraded to biomethane which is the purpose of conducting this research work... , Ph.D. (Mechanical Engineering Science)
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Preliminary design of a biogas-solar PV hybrid mini-grid system for off- grid agricultural communities

- Bambokela, J.E., Belaid, M., Muzenda, E.

  • Authors: Bambokela, J.E. , Belaid, M. , Muzenda, E.
  • Date: 2020
  • Subjects: Agricultural , Biogas , Hybrid
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/475292 , uj:42870 , Citation: Bambokela, J.E., Belaid, M. & Muzenda, E. 2020. Preliminary design of a biogas-solar PV hybrid mini-grid system for off- grid agricultural communities.
  • Description: Abstract: Mini-grid technologies are rapidly growing and occupying predominant place in Sub-Saharan Africa (SSA). Rural electrification rate is drastically rising because of the wide adoption of mini-grid systems in off-grid communities. However, there is still a lot of efforts needed from a regulatory, technological, and financial point of view. The mini-grid concept is currently being reviewed by African energy stakeholders to be integrated in their national and regional energy plan. To achieve an effective integration, the design of mini-grid set-ups must be understood. To understand its design, various factors such as the system components, the sizing and optimization tools and major implementation phases must be considered carefully. For this reason, this paper seeks to define the concept of mini-grid and propose a biogas-solar Photovoltaic (PV) hybrid mini-grid (BSPVHM) as a power solution for underserved agricultural communities.
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Design of a biodigester to treat cow dung in Botswana

- Valela, Innocent, Muzenda, Edison

  • Authors: Valela, Innocent , Muzenda, Edison
  • Date: 2019
  • Subjects: Biogas , Cow dung , Design
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/403986 , uj:33871 , Citation: Valela, I. & Muzenda, E. 2019. Design of a biodigester to treat cow dung in Botswana.
  • Description: Abstract: The biogas potential of Botswana, a cattle rich nation is explored using dung as a substrate. Biogas could be a good renewable and clean substitute for other forms of energy in rural Botswana, however, the technical and socio-economic potential remains largely unexploited. In this study, the cattle dung was characterized, followed by a lab-scale experiments on the biogas potential yields from the dung. The bio-digester design was selected using the multi criteria decision analysis. From the six digester models that were evaluated for selection, the KVIC was found to be the most suitable with its size ranging from 10 to 100 m3. The bio-digester was subsequently designed using data and mathematical models obtained from literature. The biogas plant was designed for Lemcke’s cattle farm, the best selected site, with 5000 herds. The feedstock was found to have an in-situ density of 1410 kg/m3 with a total solids (TS) content of 18.9%, volatile solids (TS) content of 80%. The suitable digester size was found to be 20 m3. An energy audit showed that the plant had a potential to produce a surplus of 45.3 MWh of energy annually.
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Determination of the potential impact of domestic Anaerobic Digester Systems: a community based research initiative in rural Bangladesh

- Rahman, Khondokar M., Melville, Lynsey, Edwards, David J., Fulford, David, Thwala, Wellington Didibhuku

  • Authors: Rahman, Khondokar M. , Melville, Lynsey , Edwards, David J. , Fulford, David , Thwala, Wellington Didibhuku
  • Date: 2019
  • Subjects: Anaerobic digestion , Biogas , Bangladesh
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/405057 , uj:33996 , Citation: Rahman, K.M., et al. 2019 : Determination of the potential impact of domestic Anaerobic Digester Systems: a community based research initiative in rural Bangladesh.
  • Description: Abstract : This research examines the potential impact of domestic anaerobic digester (AD) systems adopted in Bangladesh and similar developing countries. Cattle dung and poultry litter feed stocks were specifically investigated, because these were freely available and plentiful to people living within agricultural areas of rural Bangladesh. Data was collected to ascertain whether these two representative AD facility types provide tangible social, economic and environmental impact that benefits homeowners. Primary quantitative and qualitative data was obtained by field data collection, and meeting with expert groups and stakeholders. Empirical analysis conducted revealed that variations were found in the biomass feedstocks available on different sites but also differences were apparent in terms of the operations and maintenance (O and M) systems of the biogas plants operated. The biogas and methane yield variation was also measured, and variations were found in the cattle dung and poultry litter AD yield capacity. Overall, 64% of feedstock was utilised, 91% of biogas plants remain underfed and energy yield efficiency was 57% from cattle smallholdings’ AD and 28% from poultry farms’ AD. These results showed that small scale AD can offer a significant impact upon rural lifestyles through augmented economics, improved social activities, relationship building with neighbours and improved lifestyle achieved via time savings accrued. These results could help rural entrepreneurs, AD equipment providers and government institutions to develop a road map to implement future AD installation on a much wider geographical scale.
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Green energy (biomethane) production from codigestion of abattoir, market and grass waste as substrates

- Matheri, Anthony Njuguna, Mwiinga, Masonga Sichibanze, Zelda, Rasmeni Zenzile, Mohamed, Belaid

  • Authors: Matheri, Anthony Njuguna , Mwiinga, Masonga Sichibanze , Zelda, Rasmeni Zenzile , Mohamed, Belaid
  • Date: 2019
  • Subjects: Biogas , Biomethane , Digestion
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/402179 , uj:33645 , Citation: Matheri, A.N. et al. 2019. Green energy (biomethane) production from codigestion of abattoir, market and grass waste as substrates.
  • Description: Abstract: South Africa had in the past years been experiencing an increased energy demand. High energy crisis called for research and development in a quest for alternative energy sources (waste to energy) that drive the Nation economy forward in line with Sustainable and National development goals. Utilizing organic waste to produce biogas as a source of energy could significantly help alleviate this problem. Biogas is renewable energy, a mixture primarily consisting of methane (CH4) and carbon dioxide (CO2). The study evaluated mono-digestion of market waste (MW), abattoir waste (AW), and grass (G) and co-digestion of the three mix of substrate by determining their biomethane potential under mesophilic conditions of 37oC. It was found that the mono-digestion of grass produced high methane (1035.3 Nml) after the stipulated 14 days of hydraulic retention time, Abattoir waste, and market waste produced 722.1 Nml and 470.7 Nml of methane respectively, and the co- digestion of all substrates produced 1013.1 Nml of methane after 14 days. Co-digestion of the substrates assisted to regulate the anaerobic digestion condition or variables for biomethane production. Co-digestion of the substrate was recommended for optimality or increase in methane yield.
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Anaerobic treatment of opaque beer wastewater with enhanced biogas recovery through Acti-zyme bio augmentation

- Manyuchi, M. M., Mbohwa, Charles, Muzenda, E.

Life cycle assessment of a biogas digester : case study of a South African system

- Madushele, Nkosinathi

  • 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.
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Optimization of biogas production from City of Johannesburg market waste by anaerobic digestion for sustainable energy development

- Singh, Suraya

  • 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.
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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.
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Biogas upgrade to biomethane from landfill wastes : a review

- Dada, Opeoluwa, Mbohwa, Charles

Comparative evaluation of the performance of a bi-fuel vehicle on biogas and natural gas

- Kukoyi, T. O., Muzenda, E., Mbohwa, Charles

Investigating the potential of generating electrical energy from digester carbon waste sources at ERWAT waste water treatment facilities in the Ekurhuleni District Municipality

- Mabaso, Thembeka

  • 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.
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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.
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Biogas production from anaerobic digestion of fruit and vegetable waste from Johannesburg market

- Maile, Ireen, Muzenda, Edison, Mbohwa, Charles

Biogas purification and upgrading for vehicular fuel application

- Maile, Olivia Ireen

  • Authors: Maile, Olivia Ireen
  • Date: 2016
  • Subjects: Reneable energy sources , Biogas , Biomass energy
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/243015 , uj:25082
  • Description: M.Tech. (Chemical Engineering) , Abstract: Energy is used in the form of electricity, heat, and fuel for lighting, cooking, transportation, and manufacturing of different kind of products. South Africa has faced a long-term struggle on energy shortages which may be related to the 20% growth in the country’s electricity consumption and underinvestment on energy. Thus, the need for producing clean energy from alternative renewable and sustainable energy sources remains an attractive technology. Biogas is energy produced by anaerobic digestion of biodegradable organic waste such as garden waste, food waste, municipal waste, industrial waste and sewage sludge. However, it may not be fully exploited because it contains impurities which limit its application. It can be purified and upgraded using techniques such as high-pressure water scrubbing, pressure swing adsorption, membrane separation, activated carbon sieve, cryogenic separation, chemical absorption. This study focuses on chemical absorption as it can yield biogas with over 95 % CH4 by volume. The substrate used to produce biogas in this study was grass inoculated with cow dung. Sodium hydroxide and acetic acid were used to adjust the pH of the feedstock. The chemicals absorbents of focus are sodium hydroxide, potassium hydroxide, ammonia solution and monoethanolamine. Two kinds of setups were used for this study; biochemical methane potential (BMP) assay tests using the Bioprocess Control AMPTS II and a custom made setup using Buchner flasks. Gas Chromatography was used for biogas analysis. The raw biogas contained on average 52% CH4 by volume which improved to over 80% CH4 after CO2 absorption. The CO2 removal efficiency improved from 22% to 66% for the alkalis and was also quite comparable for MEA and NH3 as it increased from 51% to 67%. The removal efficiency for NH3 and MEA increased from 69% to 79% on average with CH4 concentration reaching over 85% volume at 40 °C. The achievable calorific value for this study ranged from 25 to 33.5 MJ/Nm3.
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Biogas use as fuel in spark ignition engines

- Kukoyi, T.O., Muzenda, E., Akinlabi, Esther Titilayo, Mashamba, A., Mbohwa, Charles, Mahlatsi, T.

Mathematical modelling for biogas production

- Matheri, Anthony Njuguna

  • 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)
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Municipal solid waste from landfills a solution to energy crisis in South Africa

- Dada, O.R., Mbohwa, Charles

  • Authors: Dada, O.R. , Mbohwa, Charles
  • Date: 2016
  • Subjects: Biogas , Landfill , Sustainable development
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/215015 , uj:21353 , Citation: Dada, O.R & Mbohwa, C. 2016. Municipal solid waste from landfills a solution to energy crisis in South Africa.
  • Description: Abstract: There is a growing interest in the management of municipal solid waste globally, and South Africa is also not relenting in its effort to turning wastes from landfill into resourceful materials or energy because of the environmental issues and job opportunities that arises from the wastes generated from household to industrial by-products. Due to the escalating increase in the cost of dumping wastes into landfills and depletion of land spaces despite the popular global campaign of waste reduction, re-use and recycling there is still a rapid increase in the tonnage of wastes that is being produced on daily basis from all works of life which results in huge quantity of waste that is disposed to landfills. This calls for an urgent need to look into possible ways of managing wastes better in such a manner that it contributes and promotes sustainable socio - economic development of the nation. This research paper focuses on the type of waste generated from the City of Johannesburg, the potential biomethane that could be produced from the organic wastes, waste collection methods around the city before disposal on landfills within the City of Johannesburg and investigation of energy generation from waste as a better waste management technique. Robinson deep landfill which is one of the biggest landfill site within the city in terms of capacity is located in the South of Johannesburg. This landfill is a potential site for the establishment of a biogas plant where landfill wastes is expected to be used as feedstocks for the production of biogas. The biogas produced will be further upgraded to biomethane for powering the City of Johannesburg metro buses.
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Performance and emission evaluation of a bi-fuel car

- Kukoyi, Temitope Oladayo

  • 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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Performance evaluation of a biogas fuelled bi-fuel vehicle

- Kukoyi, Temitope, Muzenda, Edison, Mbohwa, Charles

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