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.
- Full Text:
- 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.
- Full Text:
Value addition of coal fines and sawdust to briquettes using molasses as a binder
- Manyuchi, M. M., Mbohwa, Charles, Muzenda, E.
- Authors: Manyuchi, M. M. , Mbohwa, Charles , Muzenda, E.
- Date: 2018
- Subjects: Binder , Calorific value , Coal fines
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/280296 , uj:30116 , Citation: Manyuchi, M.M., Mbohwa, C. & Muzenda, E. 2018. Value addition of coal fines and sawdust to briquettes using molasses as a binder. South African Journal of Chemical Engineering, 26:70-73. https://doi.org/10.1016/j.sajce.2018.09.004
- Description: Abstract: In this study, the co-briquetting of coal fines saw dust and molasses as a binder is explored as an option for value addition of the wastes generated in the various industries. The effect of the saw dust concentration and the molasses concentration was investigated through measuring the briquette's calorific value, fixed carbon, compressive strength and shatter index. Addition of Ca(OH)2 was done to effect removal of sulphur from the briquette. Measurements of the briquettes physicochemical properties such as moisture content, ash content and sulphur content were measured using the standard methods. As the saw dust and the molasses concentration increased, the calorific value, fixed carbon and compressive strength increased by 16%, 8% and 50% respectively. Whereas, the shatter index decreased by 146% as the saw dust and the molasses concentration increased in relation to the coal fines. Addition of the saw dust and the molasses are therefore critical in the production of a high quality coal-saw dust-molasses briquette which does not shatter.
- Full Text:
- Authors: Manyuchi, M. M. , Mbohwa, Charles , Muzenda, E.
- Date: 2018
- Subjects: Binder , Calorific value , Coal fines
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/280296 , uj:30116 , Citation: Manyuchi, M.M., Mbohwa, C. & Muzenda, E. 2018. Value addition of coal fines and sawdust to briquettes using molasses as a binder. South African Journal of Chemical Engineering, 26:70-73. https://doi.org/10.1016/j.sajce.2018.09.004
- Description: Abstract: In this study, the co-briquetting of coal fines saw dust and molasses as a binder is explored as an option for value addition of the wastes generated in the various industries. The effect of the saw dust concentration and the molasses concentration was investigated through measuring the briquette's calorific value, fixed carbon, compressive strength and shatter index. Addition of Ca(OH)2 was done to effect removal of sulphur from the briquette. Measurements of the briquettes physicochemical properties such as moisture content, ash content and sulphur content were measured using the standard methods. As the saw dust and the molasses concentration increased, the calorific value, fixed carbon and compressive strength increased by 16%, 8% and 50% respectively. Whereas, the shatter index decreased by 146% as the saw dust and the molasses concentration increased in relation to the coal fines. Addition of the saw dust and the molasses are therefore critical in the production of a high quality coal-saw dust-molasses briquette which does not shatter.
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Economic analysis of biogas upgrading and utilization as vehicular fuel in South Africa
- Masebinu, S. O., Aboyade, A. O., Muzenda, E.
- Authors: Masebinu, S. O. , Aboyade, A. O. , Muzenda, E.
- Date: 2015
- Subjects: Biomethane , Economics , Gas processing cost
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72861 , uj:18338 , Citation: Masebinu, S.O., Aboyade, A.O. & Muzenda, E. 2015. Economic analysis of biogas upgrading and utilization as vehicular fuel in South Africa.
- Description: Abstract: Economic and sensitivity analysis of a simulated biogas upgrading plant using a gas permeation software has been presented in this study. The effect of three process conditions on gas processing cost (GPC) were simulated. An increase in CO2 increased the GPC from $0.73 to $1.39/m3 of biomethane while an increase in feed pressure increased GPC from $0.65 to $1.16/m3 of biomethane. As the feed flow rate increased from 80-140 m3/h, the product flow rate increased from 46-100 m3/h while the GPC decreases from $0.79 to $0.39/m3 of biomethane. At optimized condition, the calculated GPC was $0.46/m3 of biomethane. The NPV, IRR and BCR for producing biomethane was R15,240,343, 22.41% and 2.05 respectively with a break-even in the 5th year. Using CBG over gasoline, the end user saves 34% of annual fuel cost which is approximately R47,255 with a payback period of one year and three months for vehicle retrofitting. The fuel prices differential between gasoline and CBG as well as the overall savings, makes CBG attractive to the producer and end user.
- Full Text:
- Authors: Masebinu, S. O. , Aboyade, A. O. , Muzenda, E.
- Date: 2015
- Subjects: Biomethane , Economics , Gas processing cost
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72861 , uj:18338 , Citation: Masebinu, S.O., Aboyade, A.O. & Muzenda, E. 2015. Economic analysis of biogas upgrading and utilization as vehicular fuel in South Africa.
- Description: Abstract: Economic and sensitivity analysis of a simulated biogas upgrading plant using a gas permeation software has been presented in this study. The effect of three process conditions on gas processing cost (GPC) were simulated. An increase in CO2 increased the GPC from $0.73 to $1.39/m3 of biomethane while an increase in feed pressure increased GPC from $0.65 to $1.16/m3 of biomethane. As the feed flow rate increased from 80-140 m3/h, the product flow rate increased from 46-100 m3/h while the GPC decreases from $0.79 to $0.39/m3 of biomethane. At optimized condition, the calculated GPC was $0.46/m3 of biomethane. The NPV, IRR and BCR for producing biomethane was R15,240,343, 22.41% and 2.05 respectively with a break-even in the 5th year. Using CBG over gasoline, the end user saves 34% of annual fuel cost which is approximately R47,255 with a payback period of one year and three months for vehicle retrofitting. The fuel prices differential between gasoline and CBG as well as the overall savings, makes CBG attractive to the producer and end user.
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Removal and recovery of heavy metal from multi-component metal effluent by reduction crystallization
- Phetla, P.T., Ntuli, F., Muzenda, E.
- Authors: Phetla, P.T. , Ntuli, F. , Muzenda, E.
- Date: 2011
- Subjects: Metal powder , Electroless plating , Reduction crystallization , Chemical reduction , Reducing agent
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16255 , uj:15754 , Citation: Phetla, T.P., Ntuli F. & Muzenda E. 2011. Removal and recovery of heavy metal from multi-component metal effluent by reduction crystallization. Proceedings of Water in the Southern African Minerals Industry Conference “Quo Vadis 2020”, 15-17 February 2011, White River. The Southern African Institute of Mining and Metallurgy. ISBN: 9781920410131. pp. 73-86.
- Full Text: false
Removal and recovery of heavy metal from multi-component metal effluent by reduction crystallization
- Authors: Phetla, P.T. , Ntuli, F. , Muzenda, E.
- Date: 2011
- Subjects: Metal powder , Electroless plating , Reduction crystallization , Chemical reduction , Reducing agent
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/16255 , uj:15754 , Citation: Phetla, T.P., Ntuli F. & Muzenda E. 2011. Removal and recovery of heavy metal from multi-component metal effluent by reduction crystallization. Proceedings of Water in the Southern African Minerals Industry Conference “Quo Vadis 2020”, 15-17 February 2011, White River. The Southern African Institute of Mining and Metallurgy. ISBN: 9781920410131. pp. 73-86.
- Full Text: false
Electrolytic deposition of manganese dioxide from Nigerian manganese ore using graphite electrodes
- Muriana, R. A., Omeye, L. U., Abubakre, O. K., Muzenda, E., Ndlovu, S., Abdulkareem, A. S.
- Authors: Muriana, R. A. , Omeye, L. U. , Abubakre, O. K. , Muzenda, E. , Ndlovu, S. , Abdulkareem, A. S.
- Date: 2017
- Subjects: Driving potential , Electrolytic deposition , Electrolytic manganese dioxide
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250364 , uj:26088 , Citation: Muriana, R.A. et al. 2017. Electrolytic deposition of manganese dioxide from Nigerian manganese ore using graphite electrodes. 2nd International Engineering Conference (IEC 2017) Federal University of Technology, Minna, Nigeria.
- Description: Abstract: Super rich manganese dioxide got deposited at the anode when manganese sulphate solution was electrolytically decomposed, and the deposits called Electrolytic Manganese Dioxide (EMD). Manganese ore containing about 35.79% manganese from Ka’oje (Kebbi State, Nigeria) with pyrolusite (MnO2) as the major manganese mineral alongside iron mineral present as hematite, was the resource material. Some 1973.31g of beneficiated ore sample (75 to 600μm) was isothermally reduced with charcoal (52.17% carbon) at 6000C for one hour. The paramagnetic high oxide ore got reduced to a ferromagnetic lower oxide containing 38.90% manganese. Some 610g portions of the reduced ore were leached in varied concentrations of sulphuric acid (1.0M, 1.5M and 2.0M) at 500C for one hour and 42.36% leaching efficiency was achieved with 2.0M acid. Calculated elemental mass balance revealed that 2.0M acid dissolved 100.52g of manganese into the leach liquor as manganese sulphate along with 13.83g of iron and 7.47g of aluminium as the major elements. Each leach filtrate was purified with aqueous sodium hydroxide except some 600ml of filtrate from 2.0M acid leaching which was decomposed unpurified for comparison. The filtrates were respectively electrolyzed at 2.5V, 3.0V and 4.0V driving potentials for five hours using graphite electrodes. Analyses showed that the purified liquor extracted with 2.0M acid and electrolysed at 4.0V deposited the best quantity and quality of EMD, containing 98% MnO2. This high grade EMD is a principal precursor in Ferro-alloy production for steel making and also an important raw material for electrochemical cells and other allied manganese-based chemicals.
- Full Text:
- Authors: Muriana, R. A. , Omeye, L. U. , Abubakre, O. K. , Muzenda, E. , Ndlovu, S. , Abdulkareem, A. S.
- Date: 2017
- Subjects: Driving potential , Electrolytic deposition , Electrolytic manganese dioxide
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250364 , uj:26088 , Citation: Muriana, R.A. et al. 2017. Electrolytic deposition of manganese dioxide from Nigerian manganese ore using graphite electrodes. 2nd International Engineering Conference (IEC 2017) Federal University of Technology, Minna, Nigeria.
- Description: Abstract: Super rich manganese dioxide got deposited at the anode when manganese sulphate solution was electrolytically decomposed, and the deposits called Electrolytic Manganese Dioxide (EMD). Manganese ore containing about 35.79% manganese from Ka’oje (Kebbi State, Nigeria) with pyrolusite (MnO2) as the major manganese mineral alongside iron mineral present as hematite, was the resource material. Some 1973.31g of beneficiated ore sample (75 to 600μm) was isothermally reduced with charcoal (52.17% carbon) at 6000C for one hour. The paramagnetic high oxide ore got reduced to a ferromagnetic lower oxide containing 38.90% manganese. Some 610g portions of the reduced ore were leached in varied concentrations of sulphuric acid (1.0M, 1.5M and 2.0M) at 500C for one hour and 42.36% leaching efficiency was achieved with 2.0M acid. Calculated elemental mass balance revealed that 2.0M acid dissolved 100.52g of manganese into the leach liquor as manganese sulphate along with 13.83g of iron and 7.47g of aluminium as the major elements. Each leach filtrate was purified with aqueous sodium hydroxide except some 600ml of filtrate from 2.0M acid leaching which was decomposed unpurified for comparison. The filtrates were respectively electrolyzed at 2.5V, 3.0V and 4.0V driving potentials for five hours using graphite electrodes. Analyses showed that the purified liquor extracted with 2.0M acid and electrolysed at 4.0V deposited the best quantity and quality of EMD, containing 98% MnO2. This high grade EMD is a principal precursor in Ferro-alloy production for steel making and also an important raw material for electrochemical cells and other allied manganese-based chemicals.
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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.
- Full Text:
- 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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Parametric effects on leaching behavior of nickel-copper matte in ammonia
- Muzenda, E., Ramatsa, I. M., Ntuli, F., Abdulkareem, A. S., Afolabi, A. S.
- Authors: Muzenda, E. , Ramatsa, I. M. , Ntuli, F. , Abdulkareem, A. S. , Afolabi, A. S.
- Date: 2013
- Subjects: Ammonia concentration , Copper , Leaching temperature , Leaching time , Nickel
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17296 , uj:15867 , Citation: Muzenda, E. et al. 2013. Parametric effects on leaching behaviour of nickel-copper matte in ammonia. Particulate Science and Technology : An international Journal. 31(4): 319-325
- Description: Abstract: Please refer to full text for abstract
- Full Text:
- Authors: Muzenda, E. , Ramatsa, I. M. , Ntuli, F. , Abdulkareem, A. S. , Afolabi, A. S.
- Date: 2013
- Subjects: Ammonia concentration , Copper , Leaching temperature , Leaching time , Nickel
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17296 , uj:15867 , Citation: Muzenda, E. et al. 2013. Parametric effects on leaching behaviour of nickel-copper matte in ammonia. Particulate Science and Technology : An international Journal. 31(4): 319-325
- Description: Abstract: Please refer to full text for abstract
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Modeling of the mechanical responses of nanocrystalline metals and alloys
- Sanusi, K. O., Afolabi, A. S., Muzenda, E., Akinlabi, Esther Titilayo
- Authors: Sanusi, K. O. , Afolabi, A. S. , Muzenda, E. , Akinlabi, Esther Titilayo
- Date: 2015-07-01
- Subjects: Nanocrystalline materials , Hall-Petch relations , Nanocrystalline alloys
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/390253 , uj:5122 , ISBN 9789881404701 , http://hdl.handle.net/10210/14083
- Description: This paper reports the proposed model of the flow behaviors of nanocrystalline metals and alloys deformed at different strains, strain rates and temperatures. It incorporated the effect of grain size, high internal stresses and lattice distortions existing near boundaries to the Hall-Petch relations. The developed model was compared to that of Khan-Huang-Liang and found to be more reliable in clarifying the inverse Hall-Petch relation. Using the new proposed constitutive model, the mechanical behaviour of materials at different grain sizes for ultrafine grained to nanostructure materials at different temperatures and strain rates can be obtained. The model is also useful in predicting the response of nanocrystalline metals and alloys during the forming process.
- Full Text:
- Authors: Sanusi, K. O. , Afolabi, A. S. , Muzenda, E. , Akinlabi, Esther Titilayo
- Date: 2015-07-01
- Subjects: Nanocrystalline materials , Hall-Petch relations , Nanocrystalline alloys
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/390253 , uj:5122 , ISBN 9789881404701 , http://hdl.handle.net/10210/14083
- Description: This paper reports the proposed model of the flow behaviors of nanocrystalline metals and alloys deformed at different strains, strain rates and temperatures. It incorporated the effect of grain size, high internal stresses and lattice distortions existing near boundaries to the Hall-Petch relations. The developed model was compared to that of Khan-Huang-Liang and found to be more reliable in clarifying the inverse Hall-Petch relation. Using the new proposed constitutive model, the mechanical behaviour of materials at different grain sizes for ultrafine grained to nanostructure materials at different temperatures and strain rates can be obtained. The model is also useful in predicting the response of nanocrystalline metals and alloys during the forming process.
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Chemical absorption of carbon dioxide in biogas purification
- Maile, O. I., Muzenda, E., Tesfagiorgis, H.
- Authors: Maile, O. I. , Muzenda, E. , Tesfagiorgis, H.
- Date: 2017
- Subjects: Carbon dioxide - Absorption and adsorption , Biogas - Purification
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/223290 , uj:22451 , Citation: Maile, O.I., Muzenda, E. & Tesfagiorgis, H. 2017. Chemical absorption of carbon dioxide in biogas purification. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park.
- Description: Abstract: Biogas is produced from anaerobic digestion of organic biodegradable materials. However, its application is limited as it contains impurities such as carbon dioxide (CO2), hydrogen sulphide (H2S), and other trace gases. Chemical absorption is capable of producing gas of high methane content above 95% and has no methane losses hence it’s widely used on large scale applications. Sodium hydroxide was used for cleaning the biogas in this study at a concentration of 1M, 2M, and 3M. The effect of concentration on absorption and CO2 removal efficiency was studied. It was observed that an increase in concentration lead to an increase in the absorption rate and the removal efficiency respectively. The highest removal efficiency was recorded to be 66%.
- Full Text:
- Authors: Maile, O. I. , Muzenda, E. , Tesfagiorgis, H.
- Date: 2017
- Subjects: Carbon dioxide - Absorption and adsorption , Biogas - Purification
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/223290 , uj:22451 , Citation: Maile, O.I., Muzenda, E. & Tesfagiorgis, H. 2017. Chemical absorption of carbon dioxide in biogas purification. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park.
- Description: Abstract: Biogas is produced from anaerobic digestion of organic biodegradable materials. However, its application is limited as it contains impurities such as carbon dioxide (CO2), hydrogen sulphide (H2S), and other trace gases. Chemical absorption is capable of producing gas of high methane content above 95% and has no methane losses hence it’s widely used on large scale applications. Sodium hydroxide was used for cleaning the biogas in this study at a concentration of 1M, 2M, and 3M. The effect of concentration on absorption and CO2 removal efficiency was studied. It was observed that an increase in concentration lead to an increase in the absorption rate and the removal efficiency respectively. The highest removal efficiency was recorded to be 66%.
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Environmental sustainability : multi-criteria decision analysis for resource recovery from organic fraction of municipal solid waste
- Masebinu, S. O., Akinlabi, Esther Titilayo, Muzenda, E., Mbohwa, Charles, Aboyade, A. O., Mahlatsi, T.
- Authors: Masebinu, S. O. , Akinlabi, Esther Titilayo , Muzenda, E. , Mbohwa, Charles , Aboyade, A. O. , Mahlatsi, T.
- Date: 2016
- Subjects: Environmental sustainability , Recycling (Waste, etc.) - South Africa - Johannesburg , Anaerobic digestion , Integrated solid waste management - South Africa - Johannesburg
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/370881 , http://hdl.handle.net/10210/217190 , uj:21609 , Citation: Masebinu, S.O. et al. 2016. Environmental sustainability : multi-criteria decision analysis for resource recovery from organic fraction of municipal solid waste.
- Description: Abstract: Landfills within the City of Johannesburg (CoJ) are running out of airspace. To slow down airspace consumption rate, waste discharged at these landfills must be minimised, and where possible recover useful resources. A multi-criteria decision tool, the Analytical Hierarchy Process (AHP) was employed to appropriate technologies for fruit and vegetables waste discharge at Robinson Deep landfill. The goal of the approach is environmental sustainability. Pairwise comparison of four criteria and four technology alternatives were investigated. Data used were retrieved from a research group and consultations with waste to energy experts. Of the four technology alternatives, anaerobic digestion (AD) is the most preferred. Incineration technology has 49.42% preference to AD because it is perceived to reduce the bulkiness of waste discharged at the landfill. Composting has 25.24% preference to AD and it is believed to encourage home management of waste. Consistency ratio for all pairwise comparison was less than 0.1.
- Full Text:
- Authors: Masebinu, S. O. , Akinlabi, Esther Titilayo , Muzenda, E. , Mbohwa, Charles , Aboyade, A. O. , Mahlatsi, T.
- Date: 2016
- Subjects: Environmental sustainability , Recycling (Waste, etc.) - South Africa - Johannesburg , Anaerobic digestion , Integrated solid waste management - South Africa - Johannesburg
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/370881 , http://hdl.handle.net/10210/217190 , uj:21609 , Citation: Masebinu, S.O. et al. 2016. Environmental sustainability : multi-criteria decision analysis for resource recovery from organic fraction of municipal solid waste.
- Description: Abstract: Landfills within the City of Johannesburg (CoJ) are running out of airspace. To slow down airspace consumption rate, waste discharged at these landfills must be minimised, and where possible recover useful resources. A multi-criteria decision tool, the Analytical Hierarchy Process (AHP) was employed to appropriate technologies for fruit and vegetables waste discharge at Robinson Deep landfill. The goal of the approach is environmental sustainability. Pairwise comparison of four criteria and four technology alternatives were investigated. Data used were retrieved from a research group and consultations with waste to energy experts. Of the four technology alternatives, anaerobic digestion (AD) is the most preferred. Incineration technology has 49.42% preference to AD because it is perceived to reduce the bulkiness of waste discharged at the landfill. Composting has 25.24% preference to AD and it is believed to encourage home management of waste. Consistency ratio for all pairwise comparison was less than 0.1.
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Effect of chemicals treatment and fiber loading on mechanical properties of borassus (Toddy palm) fiber/epoxy composites
- Reddy, K. Obi, Maheswari, C. Uma, Reddy, K. Ramakrishna, Shukla, M., Muzenda, E., Rajulu, A. Varada
- Authors: Reddy, K. Obi , Maheswari, C. Uma , Reddy, K. Ramakrishna , Shukla, M. , Muzenda, E. , Rajulu, A. Varada
- Date: 2015
- Subjects: Borassus fruit fiber , Chemical treatments , Spectroscopy
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/73565 , uj:18426 , Citation: Reddy, K.O. et al. 2015. Effect of chemicals treatment and fiber loading on mechanical properties of borassus (Toddy palm) fiber/epoxy composites.
- Description: Abstract: The aim of the present study was to investigate and compare the mechanical properties of untreated and chemically modified Borassus fiber reinforced epoxy composites. Composites were prepared by hand lay-up process by reinforcing Borassus fibers with epoxy matrix. To improve the fiber-matrix adhesion properties, alkali (NaOH), and alkali combined with silane (3- aminopropyltriethoxysilane) treatments on the fibers surface were carried out. Examinations through Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were conducted to investigate the structural and physical properties of the Borassus fibers. Tensile properties such as modulus and strength of the composites made by chemically modified and untreated Borassus fibers were studied using a Universal Testing Machine (UTM). Based on the experimental results, it was found that the tensile properties of the Borassus reinforced epoxy composites were significantly improved, as compared with the neat epoxy. It was also found that the fiber treated with combination of alkali and silane exhibited superior mechanical properties as compared with alkali and untreated fiber composites. The nature of fiber/matrix interface was examined through SEM of cryo-fractured samples. Chemical resistance of composites was also found to be improved with chemically modified fiber composites.
- Full Text:
- Authors: Reddy, K. Obi , Maheswari, C. Uma , Reddy, K. Ramakrishna , Shukla, M. , Muzenda, E. , Rajulu, A. Varada
- Date: 2015
- Subjects: Borassus fruit fiber , Chemical treatments , Spectroscopy
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/73565 , uj:18426 , Citation: Reddy, K.O. et al. 2015. Effect of chemicals treatment and fiber loading on mechanical properties of borassus (Toddy palm) fiber/epoxy composites.
- Description: Abstract: The aim of the present study was to investigate and compare the mechanical properties of untreated and chemically modified Borassus fiber reinforced epoxy composites. Composites were prepared by hand lay-up process by reinforcing Borassus fibers with epoxy matrix. To improve the fiber-matrix adhesion properties, alkali (NaOH), and alkali combined with silane (3- aminopropyltriethoxysilane) treatments on the fibers surface were carried out. Examinations through Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were conducted to investigate the structural and physical properties of the Borassus fibers. Tensile properties such as modulus and strength of the composites made by chemically modified and untreated Borassus fibers were studied using a Universal Testing Machine (UTM). Based on the experimental results, it was found that the tensile properties of the Borassus reinforced epoxy composites were significantly improved, as compared with the neat epoxy. It was also found that the fiber treated with combination of alkali and silane exhibited superior mechanical properties as compared with alkali and untreated fiber composites. The nature of fiber/matrix interface was examined through SEM of cryo-fractured samples. Chemical resistance of composites was also found to be improved with chemically modified fiber composites.
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Tyre derived fuel as an alternative fuel for CI engines
- Pilusa, T.J, Shukla, M., Muzenda, E.
- Authors: Pilusa, T.J , Shukla, M. , Muzenda, E.
- Date: 2013
- Subjects: Tyre derived fuel-diesel , Waste tyre pyrolysis , Alternative fuel , Crude oil
- Type: Article
- Identifier: uj:4957 , http://hdl.handle.net/10210/13058
- Description: The study presented in this article investigated the potential use of tyre derived fuel-diesel blends as an alternative low cost fuel for compression ignition engines. A short review was conducted on waste tyre pyrolysis technology and its benefits in addressing the waste tyre management while providing an alternative usable fuel for diesel engines. Crude oil obtained from slow pyrolysis of waste tyres was distillated and its respective fractions were characterized and blended with low sulphur diesel fuel for fuelling a stationery truck engine linked to a hydraulic dynamometer. The test results revealed that fuel fraction blends with low sulphur diesel can be used to fuel a conventional compression ignition engine, however special attention is required to manage the exhausts emission due to high concentration of sulphur dioxide. There is no doubt that tyre derived fuel has a potential as future alternative fuel for compression ignition engines.
- Full Text:
- Authors: Pilusa, T.J , Shukla, M. , Muzenda, E.
- Date: 2013
- Subjects: Tyre derived fuel-diesel , Waste tyre pyrolysis , Alternative fuel , Crude oil
- Type: Article
- Identifier: uj:4957 , http://hdl.handle.net/10210/13058
- Description: The study presented in this article investigated the potential use of tyre derived fuel-diesel blends as an alternative low cost fuel for compression ignition engines. A short review was conducted on waste tyre pyrolysis technology and its benefits in addressing the waste tyre management while providing an alternative usable fuel for diesel engines. Crude oil obtained from slow pyrolysis of waste tyres was distillated and its respective fractions were characterized and blended with low sulphur diesel fuel for fuelling a stationery truck engine linked to a hydraulic dynamometer. The test results revealed that fuel fraction blends with low sulphur diesel can be used to fuel a conventional compression ignition engine, however special attention is required to manage the exhausts emission due to high concentration of sulphur dioxide. There is no doubt that tyre derived fuel has a potential as future alternative fuel for compression ignition engines.
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Factors influencing chemical absorption of CO2 and H2S in biogas : a review
- Maile, O.I., Tesfagiorgis, H., Muzenda, E.
- Authors: Maile, O.I. , Tesfagiorgis, H. , Muzenda, E.
- Date: 2015
- Subjects: Absorption rate , Efficiency , Solvent
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72927 , uj:18345 , Citation: Maile, O.I., Tesfagiorgis, H. & Muzenda, E. 2015. Factors influencing chemical absorption of CO2 and H2S in biogas : a review.
- Description: Abstract: Absorption is a process in which a substance (solute) is brought into contact with a solvent normally for a purpose of separation, which can be either physical or chemical. pH and concentration of the solvent, temperature of both the gas and the solvent, and absorbing surface area influence the absorption process. pH affect the absorption rate and if an acid or base is added into the system the absorption rate is lowered. Concentration of carbon dioxide in the gas stream and the loading rate influence the rate of absorption. MEA has an optimum absorption rate at liquid temperature of 35 °C. Ammonia has high removal efficiency at ambient temperature and there exists a direct relationship between absorption rate and temperature. Absorption of CO2 with sodium hydroxide is normally done at a temperature range of - 1-16 °C (30-60 °F). Calcium oxide requires high temperature for absorption ranging from 300-390 °C, while 22-80 °C is used for H2S absorption with K2CO3. A linear increase results from heating the CO2 gas stream prior to absorption. The rate of absorption is influenced by the contact area between the absorbing fluid and the gas.
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- Authors: Maile, O.I. , Tesfagiorgis, H. , Muzenda, E.
- Date: 2015
- Subjects: Absorption rate , Efficiency , Solvent
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/72927 , uj:18345 , Citation: Maile, O.I., Tesfagiorgis, H. & Muzenda, E. 2015. Factors influencing chemical absorption of CO2 and H2S in biogas : a review.
- Description: Abstract: Absorption is a process in which a substance (solute) is brought into contact with a solvent normally for a purpose of separation, which can be either physical or chemical. pH and concentration of the solvent, temperature of both the gas and the solvent, and absorbing surface area influence the absorption process. pH affect the absorption rate and if an acid or base is added into the system the absorption rate is lowered. Concentration of carbon dioxide in the gas stream and the loading rate influence the rate of absorption. MEA has an optimum absorption rate at liquid temperature of 35 °C. Ammonia has high removal efficiency at ambient temperature and there exists a direct relationship between absorption rate and temperature. Absorption of CO2 with sodium hydroxide is normally done at a temperature range of - 1-16 °C (30-60 °F). Calcium oxide requires high temperature for absorption ranging from 300-390 °C, while 22-80 °C is used for H2S absorption with K2CO3. A linear increase results from heating the CO2 gas stream prior to absorption. The rate of absorption is influenced by the contact area between the absorbing fluid and the gas.
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An investigation into the effect of temperature on the leaching of copper-matte
- Muzenda, E., Ramatsa, I.M., Ntuli, F., Belaid, M., Tshwabi, P.M
- Authors: Muzenda, E. , Ramatsa, I.M. , Ntuli, F. , Belaid, M. , Tshwabi, P.M
- Date: 2011
- Subjects: Cementation , Diffusion controlled , Leaching , Matte
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/17266 , uj:15864 , Muzenda, E. et al. 2011. An investigation into the effect of temperature on the leaching of coppermatte. World Academy of Science, engineering and Technology 76 (2011) : cited by EA Delgado, ÁO Nuñez - congresominas.co.pe
- Description: Abstract: Please refer to full text for abstract
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- Authors: Muzenda, E. , Ramatsa, I.M. , Ntuli, F. , Belaid, M. , Tshwabi, P.M
- Date: 2011
- Subjects: Cementation , Diffusion controlled , Leaching , Matte
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/17266 , uj:15864 , Muzenda, E. et al. 2011. An investigation into the effect of temperature on the leaching of coppermatte. World Academy of Science, engineering and Technology 76 (2011) : cited by EA Delgado, ÁO Nuñez - congresominas.co.pe
- Description: Abstract: Please refer to full text for abstract
- Full Text:
Renewable energy: deployment and the roles of energy storage
- Masebinu, S. O., Akinlabi, Esther Titilayo, Muzenda, E., Aboyade, A. O.
- Authors: Masebinu, S. O. , Akinlabi, Esther Titilayo , Muzenda, E. , Aboyade, A. O.
- Date: 2016
- Subjects: Energy storage , Environment , Renewable energy , Sustainability
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93707 , uj:20381 , Citation: Masebinu, S.O. et al. 2016. Renewable energy: deployment and the roles of energy storage.
- Description: Abstract: Hydro energy still remains the highest RE contributor to electricity generation globally, nevertheless, trends in solar and wind energy has shown increasing investment in RE. Though a decline in investment was observed between 2012 and 2013, yet investment in RE exceeded that of non-RE in the excess of $80 billion dollar. In 2014, investment increased by 16%. As developed countries get saturated with RE technologies, developing countries are now the focus for investment. Wistfully, path dependency problem, lack of adequate infrastructure and policy framework have been highlighted as the major barrier to RE deployment in developing countries. Also, lack of harmonised government agency for RE implementation, incentives and educational gap are the institutional and social barriers. Energy Storage (ES) is being promoted as the “game changer” with capability of smoothening the variability associated with the two RE technologies, wind and solar, with the highest deployment rate. Recent developments are indicative of cost reduction for ES. This paper therefore presents a concise and holistic review of renewable energy (RE) technologies for electricity generation and assess the roles of ES in mitigating intermittency associated with their generation profile.
- Full Text:
- Authors: Masebinu, S. O. , Akinlabi, Esther Titilayo , Muzenda, E. , Aboyade, A. O.
- Date: 2016
- Subjects: Energy storage , Environment , Renewable energy , Sustainability
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93707 , uj:20381 , Citation: Masebinu, S.O. et al. 2016. Renewable energy: deployment and the roles of energy storage.
- Description: Abstract: Hydro energy still remains the highest RE contributor to electricity generation globally, nevertheless, trends in solar and wind energy has shown increasing investment in RE. Though a decline in investment was observed between 2012 and 2013, yet investment in RE exceeded that of non-RE in the excess of $80 billion dollar. In 2014, investment increased by 16%. As developed countries get saturated with RE technologies, developing countries are now the focus for investment. Wistfully, path dependency problem, lack of adequate infrastructure and policy framework have been highlighted as the major barrier to RE deployment in developing countries. Also, lack of harmonised government agency for RE implementation, incentives and educational gap are the institutional and social barriers. Energy Storage (ES) is being promoted as the “game changer” with capability of smoothening the variability associated with the two RE technologies, wind and solar, with the highest deployment rate. Recent developments are indicative of cost reduction for ES. This paper therefore presents a concise and holistic review of renewable energy (RE) technologies for electricity generation and assess the roles of ES in mitigating intermittency associated with their generation profile.
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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.
- Full Text:
- 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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Waste to energy technologies from organics fraction of municipal solid waste
- Matheri, A.N., Mbohwa, Charles, Belaid, M., Seodigeng, T., Ngila, J.C., Muzenda, E.
- Authors: Matheri, A.N. , Mbohwa, Charles , Belaid, M. , Seodigeng, T. , Ngila, J.C. , Muzenda, E.
- Date: 2016
- Subjects: Anaerobic , Co-digestion , Digesters
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214143 , uj:21243 , Citation: Matheri, A.N. et al. 2016. Waste to energy technologies from organics fraction of municipal solid waste.
- Description: Abstract: With rapid economic growth and increased urbanization, South Africa faces the problem of municipal solid waste (MSW) disposal and pressing the need for waste to energy recovery. Nowadays, renewable energy is the key consideration in the discussion of the sustainable worldwide energy system that reduces global climate change, human health problems, and environmental degradation. Sustainable development requires the sustainable supply of clean and affordable renewable energy. The renewable energy source such as bioenergy, solar energy, wind energy, hydropower, geothermal is usually viewed as sustainable energy sources that drive economic development. Wastes are convertible to useful energy through waste to energy (WtE) technologies. In this study, renewable energy technologies from the organic fraction of municipal solid waste (OFMSW) and their relation to sustainable development are discussed. Via the application of the simple multi-attribute rating (SMART) technique of multiple-criteria decision analysis (MCDA) and analytical hierarchy process (AHP) as a decision support tool, the most preferred model option for WtE technology was selected from a list of potential alternatives available in the market base on environmental, sociocultural, technical and economical consideration. From our investigation into the City of Johannesburg Landfill, the OFMSW had the highest fraction that comprises of 34% in portion. From MCDA-AHP results, anaerobic digestion was the most preferred technology of choice, taking into consideration environmental preservation as the ultimate goal.
- Full Text:
- Authors: Matheri, A.N. , Mbohwa, Charles , Belaid, M. , Seodigeng, T. , Ngila, J.C. , Muzenda, E.
- Date: 2016
- Subjects: Anaerobic , Co-digestion , Digesters
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214143 , uj:21243 , Citation: Matheri, A.N. et al. 2016. Waste to energy technologies from organics fraction of municipal solid waste.
- Description: Abstract: With rapid economic growth and increased urbanization, South Africa faces the problem of municipal solid waste (MSW) disposal and pressing the need for waste to energy recovery. Nowadays, renewable energy is the key consideration in the discussion of the sustainable worldwide energy system that reduces global climate change, human health problems, and environmental degradation. Sustainable development requires the sustainable supply of clean and affordable renewable energy. The renewable energy source such as bioenergy, solar energy, wind energy, hydropower, geothermal is usually viewed as sustainable energy sources that drive economic development. Wastes are convertible to useful energy through waste to energy (WtE) technologies. In this study, renewable energy technologies from the organic fraction of municipal solid waste (OFMSW) and their relation to sustainable development are discussed. Via the application of the simple multi-attribute rating (SMART) technique of multiple-criteria decision analysis (MCDA) and analytical hierarchy process (AHP) as a decision support tool, the most preferred model option for WtE technology was selected from a list of potential alternatives available in the market base on environmental, sociocultural, technical and economical consideration. From our investigation into the City of Johannesburg Landfill, the OFMSW had the highest fraction that comprises of 34% in portion. From MCDA-AHP results, anaerobic digestion was the most preferred technology of choice, taking into consideration environmental preservation as the ultimate goal.
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Diffusion in saturated clayey barrier medium
- Agbenyeku, E. E., Muzenda, E., Msibi, M. I.
- Authors: Agbenyeku, E. E. , Muzenda, E. , Msibi, M. I.
- Date: 2017
- Subjects: Leachate , Percolation , Earthen barrier
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/223036 , uj:22415 , Citation: Agbenyeku, E.E., Muzenda, E. & Msibi, M.I. 2017. Diffusion in saturated clayey barrier medium. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park.
- Description: Abstract: The design of clay/clayey barriers for the containment of buried wastes conventionally has been based on the assumption that the hydraulic conductivity controls the rate of leachate percolation. However, recent studies show that diffusion is a controlling mechanism of solute transport in many fine-grained soils. Although the measurement of the hydraulic conductivity of finegrained soils is comparatively a common practice in soil engineering, the measurement of diffusion coefficients is not. As such, it is becoming increasingly essential to assess the movement of chemicals through soil barriers due to diffusion. Studies indicate that diffusion may be an important, if not dominant mechanism of contaminant transport through waste containment barriers. This paper is therefore in line with the efforts made in the measurement of diffusion coefficients of inorganic chemicals passing through saturated soils. Herein, both steady-state and transient equations relating to the diffusive transport of inorganic chemicals are presented. A number of factors affecting diffusion coefficients are identified and a simple method for measuring diffusion coefficients for a compacted barrier is defined. The definition for the diffusion coefficient of soil called the effective diffusion coefficient, D* is seen to vary widely. Generally, the variations are due to the different factors affecting diffusion of solutes in soil and the various ways of including the volumetric water content in the governing equations. Hence, errors in interpretation and comparison of D* values can occur if the appropriate definition is not used. In a nutshell, the concept of diffusion may be unfamiliar to many soil specialists, worsened by the myriad terminologies linked to the study of diffusion in soils. Thus the study attempts to acquaint soil engineers with vital information for the measurement of diffusion coefficients for barrier designs.
- Full Text:
- Authors: Agbenyeku, E. E. , Muzenda, E. , Msibi, M. I.
- Date: 2017
- Subjects: Leachate , Percolation , Earthen barrier
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/223036 , uj:22415 , Citation: Agbenyeku, E.E., Muzenda, E. & Msibi, M.I. 2017. Diffusion in saturated clayey barrier medium. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park.
- Description: Abstract: The design of clay/clayey barriers for the containment of buried wastes conventionally has been based on the assumption that the hydraulic conductivity controls the rate of leachate percolation. However, recent studies show that diffusion is a controlling mechanism of solute transport in many fine-grained soils. Although the measurement of the hydraulic conductivity of finegrained soils is comparatively a common practice in soil engineering, the measurement of diffusion coefficients is not. As such, it is becoming increasingly essential to assess the movement of chemicals through soil barriers due to diffusion. Studies indicate that diffusion may be an important, if not dominant mechanism of contaminant transport through waste containment barriers. This paper is therefore in line with the efforts made in the measurement of diffusion coefficients of inorganic chemicals passing through saturated soils. Herein, both steady-state and transient equations relating to the diffusive transport of inorganic chemicals are presented. A number of factors affecting diffusion coefficients are identified and a simple method for measuring diffusion coefficients for a compacted barrier is defined. The definition for the diffusion coefficient of soil called the effective diffusion coefficient, D* is seen to vary widely. Generally, the variations are due to the different factors affecting diffusion of solutes in soil and the various ways of including the volumetric water content in the governing equations. Hence, errors in interpretation and comparison of D* values can occur if the appropriate definition is not used. In a nutshell, the concept of diffusion may be unfamiliar to many soil specialists, worsened by the myriad terminologies linked to the study of diffusion in soils. Thus the study attempts to acquaint soil engineers with vital information for the measurement of diffusion coefficients for barrier designs.
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Reduction crystallization of Ni, Cu, Fe and Co from a mixed metal effluent
- Phetla, T.P., Ntuli, F., Muzenda, E.
- Authors: Phetla, T.P. , Ntuli, F. , Muzenda, E.
- Date: 2012
- Subjects: Precipitation , Reduction crystallization , Chemical reduction , Heavy metal removal , Effluent treatment
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/16147 , uj:15745 , Citation: Phetla T., Ntuli F., Muzenda E. 2012. Reduction crystallization of Ni, Cu, Fe and Co from a mixed metal effluent. Journal of Industrial and Engineering Chemistry 18, 1171–1177.
- Description: Abstract: Removal and recovery of heavy metals from effluent are major concerns due to diminishing fresh water resources, depletion of exploitable ores and human and environmental health concerns. The objective of this work was to efficiently recover heavy metals from effluent in their elemental form as metallic powder by reduction crystallization. This method recovers metals in a pure form and enables them to be directly used. Experiments were conducted using mixed metal solutions of Ni, Cu, Co, and Fe in a 20 L Perspex batch reactor using hydrazine as a reducing agent and nickel powder as seeding material. Ni, Cu, Co and Fe were effectively reduced to their elemental states with removal efficiencies of over 99% for Ni and Co and about 98% for Cu and Fe. Residual concentrations obtained for Ni, Co and Fe were below 0.05 mg/L and below 1.20 mg/L for Cu. Based on the evolution of the particle size distribution (PSD) and its derived moments the dominant particulate processes identified were aggregation, growth and breakage with the possibility of nucleation in the presence of Fe. However, particle size enlargement was largely due to aggregation.
- Full Text:
- Authors: Phetla, T.P. , Ntuli, F. , Muzenda, E.
- Date: 2012
- Subjects: Precipitation , Reduction crystallization , Chemical reduction , Heavy metal removal , Effluent treatment
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/16147 , uj:15745 , Citation: Phetla T., Ntuli F., Muzenda E. 2012. Reduction crystallization of Ni, Cu, Fe and Co from a mixed metal effluent. Journal of Industrial and Engineering Chemistry 18, 1171–1177.
- Description: Abstract: Removal and recovery of heavy metals from effluent are major concerns due to diminishing fresh water resources, depletion of exploitable ores and human and environmental health concerns. The objective of this work was to efficiently recover heavy metals from effluent in their elemental form as metallic powder by reduction crystallization. This method recovers metals in a pure form and enables them to be directly used. Experiments were conducted using mixed metal solutions of Ni, Cu, Co, and Fe in a 20 L Perspex batch reactor using hydrazine as a reducing agent and nickel powder as seeding material. Ni, Cu, Co and Fe were effectively reduced to their elemental states with removal efficiencies of over 99% for Ni and Co and about 98% for Cu and Fe. Residual concentrations obtained for Ni, Co and Fe were below 0.05 mg/L and below 1.20 mg/L for Cu. Based on the evolution of the particle size distribution (PSD) and its derived moments the dominant particulate processes identified were aggregation, growth and breakage with the possibility of nucleation in the presence of Fe. However, particle size enlargement was largely due to aggregation.
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Effect of blending coal with torrefied biomass for possible application in energy production
- Authors: Mamvura, T. , Muzenda, E.
- Date: 2016
- Subjects: Coal , Biomass , Blending , Torrefaction
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93696 , uj:20382 , Citation: Mamvura, T. & Muzenda, E. 2016. Effect of blending coal with torrefied biomass for possible application in energy production.
- Description: Abstract: Emissions of greenhouse gases mostly from fossil fuels are responsible for global warming and climatic changes. This has led to research in bioenergy to reduce greenhouse emissions because bioenergy is part of the carbon cycle, and can only emit greenhouse gases that are part of the carbon cycle. The drawback is its low calorific value when it is in its raw form. Torrefaction improves its energy content to values that are comparable to coal. In this study, marula seeds and blue gum wood, two of South Africa most abundant biomass, were blended with coal both raw and torrefied to see the impact of the torrefaction process on energy density. Blending was done at different ratios to see the optimum results. Results showed that highest calorific value was obtained at 100% marula seeds and 0 % coal, and it was recommended for further studies. Blue gum wood due to its high moisture had slightly higher heating value than the reference coal but from an economical point of view it was not attractive for further studies. This showed the significance of the torrefaction process in increasing heating value of selected biomass in the hope of reducing effects of greenhouse gas emissions.
- Full Text:
- Authors: Mamvura, T. , Muzenda, E.
- Date: 2016
- Subjects: Coal , Biomass , Blending , Torrefaction
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93696 , uj:20382 , Citation: Mamvura, T. & Muzenda, E. 2016. Effect of blending coal with torrefied biomass for possible application in energy production.
- Description: Abstract: Emissions of greenhouse gases mostly from fossil fuels are responsible for global warming and climatic changes. This has led to research in bioenergy to reduce greenhouse emissions because bioenergy is part of the carbon cycle, and can only emit greenhouse gases that are part of the carbon cycle. The drawback is its low calorific value when it is in its raw form. Torrefaction improves its energy content to values that are comparable to coal. In this study, marula seeds and blue gum wood, two of South Africa most abundant biomass, were blended with coal both raw and torrefied to see the impact of the torrefaction process on energy density. Blending was done at different ratios to see the optimum results. Results showed that highest calorific value was obtained at 100% marula seeds and 0 % coal, and it was recommended for further studies. Blue gum wood due to its high moisture had slightly higher heating value than the reference coal but from an economical point of view it was not attractive for further studies. This showed the significance of the torrefaction process in increasing heating value of selected biomass in the hope of reducing effects of greenhouse gas emissions.
- Full Text: