Biogas production using the organic fraction of municipal solid waste as feedstock
- Kigozi, R., Aboyade, A., Muzenda, Edison
- Authors: Kigozi, R. , Aboyade, A. , Muzenda, Edison
- Date: 2013
- Subjects: Anaerobic digestion , Biogas , Organic fraction of municipal solid waste
- Type: Article
- Identifier: uj:4900 , ISSN 2349-1442 , http://hdl.handle.net/10210/12995
- Description: Biogas typically refers to an odourless gas produced by anaerobic digestion (AD) of biomass using microorganisms. It has an approximate composition of 70-50% Methane (a combustible gas), 30-50% Carbon dioxide and other trace gases depending on the nature of the biomass. The idea of using the organic fraction of municipal solid waste (OFMSW) or simply municipal biowaste as feedstock for biogas production represents an environmentally sustainable energy source since it improves solid waste management while simultaneously providing an alternative clean energy source. Among other applications, the gas can be used for heating, cooking and electricity generation. However, notwithstanding, OFMSW as a feedstock for AD comes with its own unique challenges compared to other forms of biomass. This paper therefore reviews the specific opportunities, challenges and techno-economics of using OFMSW as sole feedstock supply for biogas production.
- Full Text:
- Authors: Kigozi, R. , Aboyade, A. , Muzenda, Edison
- Date: 2013
- Subjects: Anaerobic digestion , Biogas , Organic fraction of municipal solid waste
- Type: Article
- Identifier: uj:4900 , ISSN 2349-1442 , http://hdl.handle.net/10210/12995
- Description: Biogas typically refers to an odourless gas produced by anaerobic digestion (AD) of biomass using microorganisms. It has an approximate composition of 70-50% Methane (a combustible gas), 30-50% Carbon dioxide and other trace gases depending on the nature of the biomass. The idea of using the organic fraction of municipal solid waste (OFMSW) or simply municipal biowaste as feedstock for biogas production represents an environmentally sustainable energy source since it improves solid waste management while simultaneously providing an alternative clean energy source. Among other applications, the gas can be used for heating, cooking and electricity generation. However, notwithstanding, OFMSW as a feedstock for AD comes with its own unique challenges compared to other forms of biomass. This paper therefore reviews the specific opportunities, challenges and techno-economics of using OFMSW as sole feedstock supply for biogas production.
- Full Text:
Solid waste quantification for the University of Johannesburg's waste to energy project
- Sebola, Rebecca, Mokgatle, Lebogang, Aboyade, Akinwale, Muzenda, Edison
- Authors: Sebola, Rebecca , Mokgatle, Lebogang , Aboyade, Akinwale , Muzenda, Edison
- Date: 2013
- Subjects: Solid waste management - South Africa - Johannesburg , Municipal solid waste - South Africa - Johannesburg , University of Johannesburg
- Type: Article
- Identifier: uj:4911 , ISSN 2349-1442 , http://hdl.handle.net/10210/13011
- Description: Economic growth, urbanization and industrialization of African cities has caused rapid increase in volume and types of municipal solid waste (MSW) and hazardous waste. The inefficient collection, management, disposal and reuse of MSW has impeded the deployment of this waste resource into energy aside the heterogeneity problem associated with it. In addressing these challenges, the South Africa Energy Development Institute (SANEDI) in partnership with the University of Johannesburg is conducting a research into the deployment of waste into energy for use as vehicular fuel. As part of this project, waste quantification was carried out at Doornfontein campus (DFC), University of Johannesburg (UJ). This study investigated the amount of bio-waste generated in UJ DFC by quantifying the entire general and garden waste stream on campus and determining its composition. 310kg of waste is averagely generated on daily basis of which 82.34% are bio-degradable.
- Full Text:
- Authors: Sebola, Rebecca , Mokgatle, Lebogang , Aboyade, Akinwale , Muzenda, Edison
- Date: 2013
- Subjects: Solid waste management - South Africa - Johannesburg , Municipal solid waste - South Africa - Johannesburg , University of Johannesburg
- Type: Article
- Identifier: uj:4911 , ISSN 2349-1442 , http://hdl.handle.net/10210/13011
- Description: Economic growth, urbanization and industrialization of African cities has caused rapid increase in volume and types of municipal solid waste (MSW) and hazardous waste. The inefficient collection, management, disposal and reuse of MSW has impeded the deployment of this waste resource into energy aside the heterogeneity problem associated with it. In addressing these challenges, the South Africa Energy Development Institute (SANEDI) in partnership with the University of Johannesburg is conducting a research into the deployment of waste into energy for use as vehicular fuel. As part of this project, waste quantification was carried out at Doornfontein campus (DFC), University of Johannesburg (UJ). This study investigated the amount of bio-waste generated in UJ DFC by quantifying the entire general and garden waste stream on campus and determining its composition. 310kg of waste is averagely generated on daily basis of which 82.34% are bio-degradable.
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The effect of extraction conditions on oil yield from waste lubricating grease
- Diphare, Motshumi, Muzenda, Edison
- Authors: Diphare, Motshumi , Muzenda, Edison
- Date: 2013
- Subjects: Waste grease , Solvent extraction , Oil extraction
- Type: Article
- Identifier: uj:4908 , ISSN 2349-1442 , http://hdl.handle.net/10210/13008
- Description: Solvent extraction is one of the cheapest and more efficient processes for waste lubricants recycling. In this short paper, the effect of extraction temperature, agitation speed and extraction time was studied. Oil recovery was enhanced by an increase in extraction temperature, time and agitation speed. The optimum extraction time and overall recovery were 12 minutes and 74% respectively.
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- Authors: Diphare, Motshumi , Muzenda, Edison
- Date: 2013
- Subjects: Waste grease , Solvent extraction , Oil extraction
- Type: Article
- Identifier: uj:4908 , ISSN 2349-1442 , http://hdl.handle.net/10210/13008
- Description: Solvent extraction is one of the cheapest and more efficient processes for waste lubricants recycling. In this short paper, the effect of extraction temperature, agitation speed and extraction time was studied. Oil recovery was enhanced by an increase in extraction temperature, time and agitation speed. The optimum extraction time and overall recovery were 12 minutes and 74% respectively.
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Adsorption of Cu and Ni from AMD using activated bentonite
- Ntuli, Freeman, Falayi, Thabo, Molala, Panelope
- Authors: Ntuli, Freeman , Falayi, Thabo , Molala, Panelope
- Date: 2014
- Subjects: Bentonite , Copper adsorption , Langmuir kinetic models , Nickel adsorption
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/387938 , uj:4901 , ISSN 2349-1442 , http://hdl.handle.net/10210/12996
- Description: The ability of activated bentonite to adsorb Cu and Ni was investigated. 6 % solid loading was chosen as the optimum solid loading for activated bentonite with 94.85% Cu and 92.05% Ni removal after 3 hours of agitation. The adsorption process followed the Langmuir isotherm and pseudo second order kinetic models. The maximum adsorption capacities were 0.297 and 0.235 mg/g for Cu and Ni respectively. The adsorption of Cu and Ni was thermodynamically spontaneous. Cu adsorption was endothermic whilst Ni adsorption was exothermic. Activated bentonite could be used for two cycles of adsorption without regeneration.
- Full Text:
- Authors: Ntuli, Freeman , Falayi, Thabo , Molala, Panelope
- Date: 2014
- Subjects: Bentonite , Copper adsorption , Langmuir kinetic models , Nickel adsorption
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/387938 , uj:4901 , ISSN 2349-1442 , http://hdl.handle.net/10210/12996
- Description: The ability of activated bentonite to adsorb Cu and Ni was investigated. 6 % solid loading was chosen as the optimum solid loading for activated bentonite with 94.85% Cu and 92.05% Ni removal after 3 hours of agitation. The adsorption process followed the Langmuir isotherm and pseudo second order kinetic models. The maximum adsorption capacities were 0.297 and 0.235 mg/g for Cu and Ni respectively. The adsorption of Cu and Ni was thermodynamically spontaneous. Cu adsorption was endothermic whilst Ni adsorption was exothermic. Activated bentonite could be used for two cycles of adsorption without regeneration.
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Economic assessment of waste tyres pyrolysis technology: a case study for Gauteng Province, South Africa
- Pilusa, Jefrey, Shukla, Mukul, Muzenda, Edison
- Authors: Pilusa, Jefrey , Shukla, Mukul , Muzenda, Edison
- Date: 2014
- Subjects: Waste tyres - South Africa - Gauteng , Waste tyre pyrolysis - South Africa - Gauteng
- Type: Article
- Identifier: uj:4905 , ISSN 2349-1442 , http://hdl.handle.net/10210/13004
- Description: This study evaluates the viability of pyrolysis technology as a treatment process for waste tyres with the aim of producing alternative fuel and other high value products. A financial model was formulated to evaluate the economic feasibility of this technology as an alternative disposal method. It was discovered that pyrolysis technology becomes more viable when there is guaranteed product off-takes at a given price. Further processing of the crude tyre oil and carbon black is important for production of consistent quality products. Gauteng province alone will require a capital injection of US $59.8 million to setup 14 waste tyres pyrolysis treatment facilities to treat 134,922 tons per annum of waste tyres with a potential investment return and gross margin of 29.79% and 34.59%, respectively. These facilities can produce up to 46.8 million litres per annum of refined tyre derived fuel at cost of $ 0.516/litre and other secondary value add products for local and export markets.
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- Authors: Pilusa, Jefrey , Shukla, Mukul , Muzenda, Edison
- Date: 2014
- Subjects: Waste tyres - South Africa - Gauteng , Waste tyre pyrolysis - South Africa - Gauteng
- Type: Article
- Identifier: uj:4905 , ISSN 2349-1442 , http://hdl.handle.net/10210/13004
- Description: This study evaluates the viability of pyrolysis technology as a treatment process for waste tyres with the aim of producing alternative fuel and other high value products. A financial model was formulated to evaluate the economic feasibility of this technology as an alternative disposal method. It was discovered that pyrolysis technology becomes more viable when there is guaranteed product off-takes at a given price. Further processing of the crude tyre oil and carbon black is important for production of consistent quality products. Gauteng province alone will require a capital injection of US $59.8 million to setup 14 waste tyres pyrolysis treatment facilities to treat 134,922 tons per annum of waste tyres with a potential investment return and gross margin of 29.79% and 34.59%, respectively. These facilities can produce up to 46.8 million litres per annum of refined tyre derived fuel at cost of $ 0.516/litre and other secondary value add products for local and export markets.
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Effect of moisture quantity on non-distillation oil extraction from SCG using methanol
- Mojapelo, Nancy, Mollagee, Mansoor, Muzenda, Edison, Mguni, Liberty L
- Authors: Mojapelo, Nancy , Mollagee, Mansoor , Muzenda, Edison , Mguni, Liberty L
- Date: 2014
- Subjects: Oil extraction , Methanol , Hexane , Spent coffee grounds
- Type: Article
- Identifier: uj:4902 , ISSN 2349-1442 , http://hdl.handle.net/10210/12997
- Description: Oil was extracted from spent coffee grounds using methanol. Methanol is not a popular solvent for oil extraction because of its toxicity but it is ideal for biodiesel production. The SCG was determined to contain 17.1 % wt% oil by extraction using hexane for 16h. The highest oil extraction 8.5 wt% was observed on a dry sample at a separation temperature of 25 ˚C representing only 50% recovery. Oil extraction was observed to depend on separation temperature and SCG water quantity. The extracted oil was characterised by a number of methods. Fourier-transform infrared spectroscopy (FTIR) results showed no difference in functional groups between hexane and methanol extracted oil. The Refractive Index (RI) results also suggested similarity in fatty acid chain length for oils extracted by these solvent. However, it was observed that oil extracted by hexane had higher amounts of FFA compared to methanol extracted oil.
- Full Text:
- Authors: Mojapelo, Nancy , Mollagee, Mansoor , Muzenda, Edison , Mguni, Liberty L
- Date: 2014
- Subjects: Oil extraction , Methanol , Hexane , Spent coffee grounds
- Type: Article
- Identifier: uj:4902 , ISSN 2349-1442 , http://hdl.handle.net/10210/12997
- Description: Oil was extracted from spent coffee grounds using methanol. Methanol is not a popular solvent for oil extraction because of its toxicity but it is ideal for biodiesel production. The SCG was determined to contain 17.1 % wt% oil by extraction using hexane for 16h. The highest oil extraction 8.5 wt% was observed on a dry sample at a separation temperature of 25 ˚C representing only 50% recovery. Oil extraction was observed to depend on separation temperature and SCG water quantity. The extracted oil was characterised by a number of methods. Fourier-transform infrared spectroscopy (FTIR) results showed no difference in functional groups between hexane and methanol extracted oil. The Refractive Index (RI) results also suggested similarity in fatty acid chain length for oils extracted by these solvent. However, it was observed that oil extracted by hexane had higher amounts of FFA compared to methanol extracted oil.
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Enrichment of biogas for use as vehicular fuel: a review of the upgrading techniques
- Masebinu, S. O., Aboyade, A., Muzenda, Edison
- Authors: Masebinu, S. O. , Aboyade, A. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Biogas enrichment
- Type: Article
- Identifier: uj:4912 , ISSN 2349-1442 , http://hdl.handle.net/10210/13012
- Description: Biogas, a renewable energy, can be captured, upgraded and used to fuel a vehicle as an alternative to fossil fuel, thus, reducing greenhouse gas emission. Biogas is environmentally hazardous if emitted directly into the environment. Increasing demand for bio-methane to be used as vehicular fuel has called for efficient use of waste and technology that is optimal yet economical. Biogas in its raw state contains impurities that reduce its heating value to be used directly as fuel, hence, a need to enhance it by upgrading to bio-methane. Several techniques exist for upgrading biogas to bio-methane. This paper present four upgrading techniques; absorption, adsorption, membrane and cryogenic techniques, a brief theoretical background, advantages and operational issues associated with each technique.
- Full Text:
- Authors: Masebinu, S. O. , Aboyade, A. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Biogas enrichment
- Type: Article
- Identifier: uj:4912 , ISSN 2349-1442 , http://hdl.handle.net/10210/13012
- Description: Biogas, a renewable energy, can be captured, upgraded and used to fuel a vehicle as an alternative to fossil fuel, thus, reducing greenhouse gas emission. Biogas is environmentally hazardous if emitted directly into the environment. Increasing demand for bio-methane to be used as vehicular fuel has called for efficient use of waste and technology that is optimal yet economical. Biogas in its raw state contains impurities that reduce its heating value to be used directly as fuel, hence, a need to enhance it by upgrading to bio-methane. Several techniques exist for upgrading biogas to bio-methane. This paper present four upgrading techniques; absorption, adsorption, membrane and cryogenic techniques, a brief theoretical background, advantages and operational issues associated with each technique.
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Evaluation of ceramic media wear characteristics on the M100 Isa Mill
- Makgamatha, Kgadi A., Mulaba-Bafubiandi, Antoine F., Randigwane, A., Bolha, W., Anyimadu, A.
- Authors: Makgamatha, Kgadi A. , Mulaba-Bafubiandi, Antoine F. , Randigwane, A. , Bolha, W. , Anyimadu, A.
- Date: 2014
- Subjects: Ceramic media , M100 Isa-Mill
- Type: Article
- Identifier: uj:4910 , ISSN 2349-1442 , http://hdl.handle.net/10210/13010
- Description: Since the installation of Isa-Mills, major improvements/studies have been made to make it more efficient. In 2006, ceramic media were introduced in the market to identify the cost effective type. This was achieved by the quality studies on different type of media both at the laboratory and pilot plant scale. In this present study, a 100 hours test was carried out in order to evaluate the wear characteristics of ceramic media branded candidate media and was compared to the standard media using the M100 Isa mill at the pilot plant. The evaluation was in the basis of comparing the relative performance of the candidate media and standard media in terms of wear rate, energy consumption and the finest of grind, whereby the following results were generated. A seasoned charge graph of both media at d80 μm vs. running time (hr) was generated and clearly highlighted the points of reaching seasoned charge for both media however, this didn’t help much in terms of finding the difference between the media because one cannot confirm the points of reaching seasoned charge by just looking at the graph but this can be confirmed by the actual size analysis of the media beads. A further comparison was made by comparing the finest of grinds from the Isa-Mill discharge and it does not necessarily gives a clear view of which media is better compared to the other. The media wear rate and energy consumption of both media were compared and the standard media showed a big variance from the candidate media in terms of wear and energy. The standard media stood out to be the cost-effective type compared to the candidate media. Its utilization in the plant will then be suggested.
- Full Text:
- Authors: Makgamatha, Kgadi A. , Mulaba-Bafubiandi, Antoine F. , Randigwane, A. , Bolha, W. , Anyimadu, A.
- Date: 2014
- Subjects: Ceramic media , M100 Isa-Mill
- Type: Article
- Identifier: uj:4910 , ISSN 2349-1442 , http://hdl.handle.net/10210/13010
- Description: Since the installation of Isa-Mills, major improvements/studies have been made to make it more efficient. In 2006, ceramic media were introduced in the market to identify the cost effective type. This was achieved by the quality studies on different type of media both at the laboratory and pilot plant scale. In this present study, a 100 hours test was carried out in order to evaluate the wear characteristics of ceramic media branded candidate media and was compared to the standard media using the M100 Isa mill at the pilot plant. The evaluation was in the basis of comparing the relative performance of the candidate media and standard media in terms of wear rate, energy consumption and the finest of grind, whereby the following results were generated. A seasoned charge graph of both media at d80 μm vs. running time (hr) was generated and clearly highlighted the points of reaching seasoned charge for both media however, this didn’t help much in terms of finding the difference between the media because one cannot confirm the points of reaching seasoned charge by just looking at the graph but this can be confirmed by the actual size analysis of the media beads. A further comparison was made by comparing the finest of grinds from the Isa-Mill discharge and it does not necessarily gives a clear view of which media is better compared to the other. The media wear rate and energy consumption of both media were compared and the standard media showed a big variance from the candidate media in terms of wear and energy. The standard media stood out to be the cost-effective type compared to the candidate media. Its utilization in the plant will then be suggested.
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Metal injection moulding as a possible processing route for porous prostheses
- Authors: Bhero, Shepherd
- Date: 2014
- Subjects: Metal injection moulding , Porous prostheses , Full-density prostheses
- Type: Article
- Identifier: uj:4903 , ISSN 2349-1442 , http://hdl.handle.net/10210/13001
- Description: Metal injection moulding (MIM) can be used to make close to full density parts. The superiority of MIM over conventional casting and machining lies in lower cost and shorter processing time. Of paramount importance is the fact that powder processing circumvents the typical casting problems that include macro-segregation and discontinuities. Thus powder processing is a possible route for manufacturing full-density prostheses devoid of casting imperfections. However, the full density metallic part is much higher than that of bone tissue and would exert skewed weight on the skeletal configuration. This paper explores the feasibility of producing high strength porous prostheses in a bid to lower the overall implant density and to a lesser extent, stiffness, so as to match the bone properties as closely as possible. Powder characteristics and sintering parameters are critical in achieving the desired end.
- Full Text:
- Authors: Bhero, Shepherd
- Date: 2014
- Subjects: Metal injection moulding , Porous prostheses , Full-density prostheses
- Type: Article
- Identifier: uj:4903 , ISSN 2349-1442 , http://hdl.handle.net/10210/13001
- Description: Metal injection moulding (MIM) can be used to make close to full density parts. The superiority of MIM over conventional casting and machining lies in lower cost and shorter processing time. Of paramount importance is the fact that powder processing circumvents the typical casting problems that include macro-segregation and discontinuities. Thus powder processing is a possible route for manufacturing full-density prostheses devoid of casting imperfections. However, the full density metallic part is much higher than that of bone tissue and would exert skewed weight on the skeletal configuration. This paper explores the feasibility of producing high strength porous prostheses in a bid to lower the overall implant density and to a lesser extent, stiffness, so as to match the bone properties as closely as possible. Powder characteristics and sintering parameters are critical in achieving the desired end.
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Non-distillation oil extraction from SCG using ethanol Propan ropan-2-ol
- Mabona, Nomfundo, Muzenda, Edison, Mollagee, Mansoor, Mguni, Liberty L
- Authors: Mabona, Nomfundo , Muzenda, Edison , Mollagee, Mansoor , Mguni, Liberty L
- Date: 2014
- Subjects: Ethanol , Propanol , Spent coffee grounds , Oil extraction
- Type: Article
- Identifier: uj:4904 , ISSN 2349-1442 , http://hdl.handle.net/10210/13002
- Description: Non-distillation oil extraction is a process whereby the step required to distillate the solvent (alcohol) to recover residual oil and by-products is eliminated. This is achieved by cooling the extraction products such that oil and some by-products become immiscible and they separate from the alcohol. The effect of Spent Coffee Grounds (SCG)/solvent ratio on non-distillation oil recovery was investigated. It was observed that recovery increased with an increase in ratio for both solvents, ethanol and propanol. The effect of separation temperature was also investigated and it was observed that the highest recovery was achieved at 15 oC. Generally it was observed that propanol recovery for non-distillation extraction was higher than that of ethanol. The main fatty acids present in the SCG oil were found to be palmitic acid (C16:0), stearic acid (C 18:0) and linoleic acid (18:2). Unsaponification values obtained for non-distillation extracted oil were 6.8 and 8.3% for ethanol and propanol respectively. These values are comparable with those of refined oil.
- Full Text:
- Authors: Mabona, Nomfundo , Muzenda, Edison , Mollagee, Mansoor , Mguni, Liberty L
- Date: 2014
- Subjects: Ethanol , Propanol , Spent coffee grounds , Oil extraction
- Type: Article
- Identifier: uj:4904 , ISSN 2349-1442 , http://hdl.handle.net/10210/13002
- Description: Non-distillation oil extraction is a process whereby the step required to distillate the solvent (alcohol) to recover residual oil and by-products is eliminated. This is achieved by cooling the extraction products such that oil and some by-products become immiscible and they separate from the alcohol. The effect of Spent Coffee Grounds (SCG)/solvent ratio on non-distillation oil recovery was investigated. It was observed that recovery increased with an increase in ratio for both solvents, ethanol and propanol. The effect of separation temperature was also investigated and it was observed that the highest recovery was achieved at 15 oC. Generally it was observed that propanol recovery for non-distillation extraction was higher than that of ethanol. The main fatty acids present in the SCG oil were found to be palmitic acid (C16:0), stearic acid (C 18:0) and linoleic acid (18:2). Unsaponification values obtained for non-distillation extracted oil were 6.8 and 8.3% for ethanol and propanol respectively. These values are comparable with those of refined oil.
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Optimal reactor network for methanol synthesis using RCC algorithm for attainable regions analysis
- Seodigeng, Tumisang, Muala, Guida
- Authors: Seodigeng, Tumisang , Muala, Guida
- Date: 2014
- Subjects: Methanol synthesis , Optimal reactor networks , Attainable regions analysis , Recursive convex control policy algorithm
- Type: Article
- Identifier: uj:4899 , ISSN 2349-1442 , http://hdl.handle.net/10210/12994
- Description: Optimal reactor network for methanol synthesis over Cu-Zn-Al catalyst has been developed by automated attainable regions analysis using the recursive convex control policy algorithm. Fundamental processes of solid catalysed gaseous reaction, cooling, mixing and heating are considered in order to develop a reactor network that can be used to attain specific optimal conditions such as maximum conversion or minimisation of the required heating or cooling surface area.
- Full Text:
- Authors: Seodigeng, Tumisang , Muala, Guida
- Date: 2014
- Subjects: Methanol synthesis , Optimal reactor networks , Attainable regions analysis , Recursive convex control policy algorithm
- Type: Article
- Identifier: uj:4899 , ISSN 2349-1442 , http://hdl.handle.net/10210/12994
- Description: Optimal reactor network for methanol synthesis over Cu-Zn-Al catalyst has been developed by automated attainable regions analysis using the recursive convex control policy algorithm. Fundamental processes of solid catalysed gaseous reaction, cooling, mixing and heating are considered in order to develop a reactor network that can be used to attain specific optimal conditions such as maximum conversion or minimisation of the required heating or cooling surface area.
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Polarization and potentiometric studies of cobalt and copper oxidised ores in ammonium chloride medium
- Mbuyi, Noella M., Mulaba-Bafubiandi, Antoine F., Adams, Feyisayo V.
- Authors: Mbuyi, Noella M. , Mulaba-Bafubiandi, Antoine F. , Adams, Feyisayo V.
- Date: 2014
- Subjects: Ammonium chloride , Copper oxide ores , Cobalt oxide ores
- Type: Article
- Identifier: uj:4909 , ISSN 2349-1442 , http://hdl.handle.net/10210/13009
- Description: This research study was conducted to evaluate the dissolution and electrochemical behaviour of low grade Cu-Co oxide ore (0.4% Cu; 3% Co) in ammonium chloride media (NH4Cl) by means of polarization and potentiometric measurements. Polarization measurements were carried out to evaluate the electrochemical behaviour as well as the leaching and re-passivation behaviour of the ores at pH of 9.5, 9.6, 9.7 and 9.8 in NH4Cl solution. In all the pH tested, the potential changed from negative to electropositive values suggesting formation of passive film on the surface of the ore which lowered the dissolution rates. Stable behaviours as were as high dissolution rate were observed at pH of 9.5. Potentiometric measurements were carried out at constant current and varying potential to study the reactivity of Cu-Co oxide ores in 0.25M, 0.5M and 1M of NH4Cl solution. In this test the dissolution rates increased with increasing concentration and the pH decreased with increasing concentration and time suggesting production of acid as oxidation reaction takes place, the ranges of pH are depicted in the Pourbaix diagrams. Stable behaviours were observed in 1M of solution. All observations made in these measurements are confirmed by AAS, XRF, SEM and XRD analysis.
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- Authors: Mbuyi, Noella M. , Mulaba-Bafubiandi, Antoine F. , Adams, Feyisayo V.
- Date: 2014
- Subjects: Ammonium chloride , Copper oxide ores , Cobalt oxide ores
- Type: Article
- Identifier: uj:4909 , ISSN 2349-1442 , http://hdl.handle.net/10210/13009
- Description: This research study was conducted to evaluate the dissolution and electrochemical behaviour of low grade Cu-Co oxide ore (0.4% Cu; 3% Co) in ammonium chloride media (NH4Cl) by means of polarization and potentiometric measurements. Polarization measurements were carried out to evaluate the electrochemical behaviour as well as the leaching and re-passivation behaviour of the ores at pH of 9.5, 9.6, 9.7 and 9.8 in NH4Cl solution. In all the pH tested, the potential changed from negative to electropositive values suggesting formation of passive film on the surface of the ore which lowered the dissolution rates. Stable behaviours as were as high dissolution rate were observed at pH of 9.5. Potentiometric measurements were carried out at constant current and varying potential to study the reactivity of Cu-Co oxide ores in 0.25M, 0.5M and 1M of NH4Cl solution. In this test the dissolution rates increased with increasing concentration and the pH decreased with increasing concentration and time suggesting production of acid as oxidation reaction takes place, the ranges of pH are depicted in the Pourbaix diagrams. Stable behaviours were observed in 1M of solution. All observations made in these measurements are confirmed by AAS, XRF, SEM and XRD analysis.
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Potentiodynamic polarisation and chronopotentiometric studies of cobalt-copper oxidised ore in sulphuric acid
- Makgamatha, Kgadi A., Mulaba-Bafubiandi, Antoine F., Adams, Feyisayo V.
- Authors: Makgamatha, Kgadi A. , Mulaba-Bafubiandi, Antoine F. , Adams, Feyisayo V.
- Date: 2014
- Subjects: Copper oxide ores , Cobalt oxide ores , Sulphuric acid
- Type: Article
- Identifier: uj:4913 , ISSN 2349-1442 , http://hdl.handle.net/10210/13013
- Description: The electrochemistry of leaching low grade Co-Cu oxidized ore containing 3.32% Co and 0.403% Cu in sulphuric acid was studied. Potentiodynamic polarization and potentiometric method were used....
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- Authors: Makgamatha, Kgadi A. , Mulaba-Bafubiandi, Antoine F. , Adams, Feyisayo V.
- Date: 2014
- Subjects: Copper oxide ores , Cobalt oxide ores , Sulphuric acid
- Type: Article
- Identifier: uj:4913 , ISSN 2349-1442 , http://hdl.handle.net/10210/13013
- Description: The electrochemistry of leaching low grade Co-Cu oxidized ore containing 3.32% Co and 0.403% Cu in sulphuric acid was studied. Potentiodynamic polarization and potentiometric method were used....
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Technological assessment of product screens (137sc16/17) performance
- Mbuyi, Noella M., Randigwane, A., Bolha, W., Anyimadu, A., Mulaba-Bafubiandi, Antoine F.
- Authors: Mbuyi, Noella M. , Randigwane, A. , Bolha, W. , Anyimadu, A. , Mulaba-Bafubiandi, Antoine F.
- Date: 2014
- Subjects: Screens performance , Particle size distribution
- Type: Article
- Identifier: uj:4907 , ISSN 2349-1442 , http://hdl.handle.net/10210/13007
- Description: Performance of two product screens (137Sc-16/17) constantly flooding at UG2 plant were assessed. Root causes for the flooding were investigated as well as a benchmarking with the performance of non-flooding screens performance. Samples for the screens 137Sc-16/17 feed and oversize were collected for three days, and prepared according to plant standards for sample preparations in order to obtain the particle size distribution (PSD). The first PSD results of the feed were given to Barcandyle which is mechanical engineering experts for screen sizing and their findings were used in this project for optimization purposes. The PSDs of the screens undersize, oversize and feed were used to draw cumulative percent passing and these graphs were used with the effective formula in order to determine screen performances. It was observed that 137SC-17 was more efficient than 137SC-16 and also that the major cause of flooding was due to the woodchips blinding the screen panels. From these findings the aperture size of 137SC-16 was changed from 0.63mm to 0.8mm. The screens still flood during spikes time due insufficient picking points for wood at UG2 plant.
- Full Text:
- Authors: Mbuyi, Noella M. , Randigwane, A. , Bolha, W. , Anyimadu, A. , Mulaba-Bafubiandi, Antoine F.
- Date: 2014
- Subjects: Screens performance , Particle size distribution
- Type: Article
- Identifier: uj:4907 , ISSN 2349-1442 , http://hdl.handle.net/10210/13007
- Description: Performance of two product screens (137Sc-16/17) constantly flooding at UG2 plant were assessed. Root causes for the flooding were investigated as well as a benchmarking with the performance of non-flooding screens performance. Samples for the screens 137Sc-16/17 feed and oversize were collected for three days, and prepared according to plant standards for sample preparations in order to obtain the particle size distribution (PSD). The first PSD results of the feed were given to Barcandyle which is mechanical engineering experts for screen sizing and their findings were used in this project for optimization purposes. The PSDs of the screens undersize, oversize and feed were used to draw cumulative percent passing and these graphs were used with the effective formula in order to determine screen performances. It was observed that 137SC-17 was more efficient than 137SC-16 and also that the major cause of flooding was due to the woodchips blinding the screen panels. From these findings the aperture size of 137SC-16 was changed from 0.63mm to 0.8mm. The screens still flood during spikes time due insufficient picking points for wood at UG2 plant.
- Full Text:
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