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.
- Full Text:
Multi-criteria analysis of different technologies for the bioenergy recovery from OFMSW
- Matheri, Anthony Njuguna, Mbohwa, Charles, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Jane Catherine
- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Anaerobic digester , Design , Bioenergy recovery
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/377197 , http://hdl.handle.net/10210/214131 , uj:21242 , Citation: Matheri, A.N. et al. 2016. Multi-criteria analysis of different technologies for the bioenergy recovery from OFMSW.
- Description: Abstract: In this study, the multi-criteria analysis model is demonstrated for evaluation and technologies from municipal solid waste (MSW) in City of Johannesburg (CoJ), South Africa. The technologies evaluation and alternation criteria for multi-criteria decision analysis (MCDA) area characterized by reviewing the literature and consulting experts in the renewable energy and waste management. MCDA was the approach employed by decision makers to make recommendation on technique employed to select the most suitable biogas digester technology for organic fraction of municipal solid waste (OFMWS) originating from the city’s landfills base on scalability, relative cost prices, available, temperature regulation, agitation, ease of construction, operation and maintenance. The result for digester type indicated that the “complete mix, continuously stirred anaerobic digester” (CSAD) was preferred with 79% preference to other anaerobic digester technologies for energy recovery.
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- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Anaerobic digester , Design , Bioenergy recovery
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/377197 , http://hdl.handle.net/10210/214131 , uj:21242 , Citation: Matheri, A.N. et al. 2016. Multi-criteria analysis of different technologies for the bioenergy recovery from OFMSW.
- Description: Abstract: In this study, the multi-criteria analysis model is demonstrated for evaluation and technologies from municipal solid waste (MSW) in City of Johannesburg (CoJ), South Africa. The technologies evaluation and alternation criteria for multi-criteria decision analysis (MCDA) area characterized by reviewing the literature and consulting experts in the renewable energy and waste management. MCDA was the approach employed by decision makers to make recommendation on technique employed to select the most suitable biogas digester technology for organic fraction of municipal solid waste (OFMWS) originating from the city’s landfills base on scalability, relative cost prices, available, temperature regulation, agitation, ease of construction, operation and maintenance. The result for digester type indicated that the “complete mix, continuously stirred anaerobic digester” (CSAD) was preferred with 79% preference to other anaerobic digester technologies for energy recovery.
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Modelling the kinetic of biogas production from co-digestion of pig waste and grass clippings
- Matheri, Anthony Njuguna, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Catherine Jane
- Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Catherine Jane
- Date: 2016
- Subjects: Anaerobic , Co-digestion , Kinetics , Mesophilic temperature , Modified gompertz
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93635 , uj:20372 , Citation: Matheri, A.N. et al. 2016. Modelling the kinetic of biogas production from co-digestion of pig waste and grass clippings.
- Description: Abstract: This work investigated the use of laboratory batch anaerobic digester to derive kinetics parameters for anaerobic co-digestion of pig waste and grass clippings. Laboratory experiment data from 10 litres batch anaerobic digester operating at ambient mesophilic temperature of 37 0C and pH of 6.9 was used to derive parameters for modified Gompertz model. The carbon/nitrogen (C/N) ratio of Pig waste was found to be 16.16 and grass clippings to be 20.54. Through co-digestion in ratio of 1:1, the C/N ratio settled at 17.28. The actual biogas yield was found to be 7725 ml/g COD. In the model of biogas production prediction, the kinetics constants of A (ml/g COD), μ (ml/g COD. day), λ (day) was 7920.70, 701.35, 1.61 respectively with coefficient of determination (R2) of 0.9994. Modified Gompertz plot showed better correlation of cumulative biogas production and these results show biogas production can be enhanced from co-digestion of substrates.
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- Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Catherine Jane
- Date: 2016
- Subjects: Anaerobic , Co-digestion , Kinetics , Mesophilic temperature , Modified gompertz
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93635 , uj:20372 , Citation: Matheri, A.N. et al. 2016. Modelling the kinetic of biogas production from co-digestion of pig waste and grass clippings.
- Description: Abstract: This work investigated the use of laboratory batch anaerobic digester to derive kinetics parameters for anaerobic co-digestion of pig waste and grass clippings. Laboratory experiment data from 10 litres batch anaerobic digester operating at ambient mesophilic temperature of 37 0C and pH of 6.9 was used to derive parameters for modified Gompertz model. The carbon/nitrogen (C/N) ratio of Pig waste was found to be 16.16 and grass clippings to be 20.54. Through co-digestion in ratio of 1:1, the C/N ratio settled at 17.28. The actual biogas yield was found to be 7725 ml/g COD. In the model of biogas production prediction, the kinetics constants of A (ml/g COD), μ (ml/g COD. day), λ (day) was 7920.70, 701.35, 1.61 respectively with coefficient of determination (R2) of 0.9994. Modified Gompertz plot showed better correlation of cumulative biogas production and these results show biogas production can be enhanced from co-digestion of substrates.
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The kinetic of biogas rate from cow dung and grass clippings
- Matheri, Anthony Njuguna, Belaid, Mohammed, Seodigeng, Tumisang, Ngila, Catherine Jane
- Authors: Matheri, Anthony Njuguna , Belaid, Mohammed , Seodigeng, Tumisang , Ngila, Catherine Jane
- Date: 2016
- Subjects: Anaerobic digestion , Kinetic models , Modified Gompertz
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91512 , uj:20110 , Citation: Matheri, A.N. et al. 2016. The kinetic of biogas rate from cow dung and grass clippings.
- Description: Abstract:In this study, we investigated the use of laboratory batch anaerobic digester to derive kinetics parameters for anaerobic co-digestion of cow dung and grass clippings. The Carbon/Nitrogen (C/N) ratio of cow dung was found to be 17.17 and grass clippings to be 20.54. Through co-digestion, the C/N ratio settled at 19.08. Laboratory experimental data from 10 litres batch anaerobic digester operating at mesophilic temperature of 37 0C and pH of 6.9 was used to derive parameters for Modified Gompertz model. The actual biogas yield was found to be 4370 ml/g COD. In the model of biogas production prediction, the kinetics constants of A (ml/g COD), μ (ml/g COD. day), λ (day) were 4319.20, 939.71, 1.91 respectively with coefficient of determination (R2) of 0.996.
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- Authors: Matheri, Anthony Njuguna , Belaid, Mohammed , Seodigeng, Tumisang , Ngila, Catherine Jane
- Date: 2016
- Subjects: Anaerobic digestion , Kinetic models , Modified Gompertz
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91512 , uj:20110 , Citation: Matheri, A.N. et al. 2016. The kinetic of biogas rate from cow dung and grass clippings.
- Description: Abstract:In this study, we investigated the use of laboratory batch anaerobic digester to derive kinetics parameters for anaerobic co-digestion of cow dung and grass clippings. The Carbon/Nitrogen (C/N) ratio of cow dung was found to be 17.17 and grass clippings to be 20.54. Through co-digestion, the C/N ratio settled at 19.08. Laboratory experimental data from 10 litres batch anaerobic digester operating at mesophilic temperature of 37 0C and pH of 6.9 was used to derive parameters for Modified Gompertz model. The actual biogas yield was found to be 4370 ml/g COD. In the model of biogas production prediction, the kinetics constants of A (ml/g COD), μ (ml/g COD. day), λ (day) were 4319.20, 939.71, 1.91 respectively with coefficient of determination (R2) of 0.996.
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Waste to energy bio-digester selection and design model for the organic fraction of municipal solid waste
- Matheri, Anthony Njuguna, Mbohwa, Charles, Ntuli, Freeman, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Jane Catherine, Njenga, Cecilia Kinuthia
- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Ntuli, Freeman , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine , Njenga, Cecilia Kinuthia
- Date: 2017
- Subjects: Anaerobic digestion , Bio-digester , Mesophilic temperature
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/250904 , uj:26157 , Citation: Matheri, A.N. et al. 2017. Waste to energy bio-digester selection and design model for the organic fraction of municipal solid waste.
- Description: Abstract: Please refer to full text to view abstract
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- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Ntuli, Freeman , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine , Njenga, Cecilia Kinuthia
- Date: 2017
- Subjects: Anaerobic digestion , Bio-digester , Mesophilic temperature
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/250904 , uj:26157 , Citation: Matheri, A.N. et al. 2017. Waste to energy bio-digester selection and design model for the organic fraction of municipal solid waste.
- Description: Abstract: Please refer to full text to view abstract
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Design model selection and dimensioning of anaerobic digester for the OFMSW
- Matheri, Anthony Njuguna, Mbohwa, Charles, Seodigeng, Tumisang, Ngila, Jane Catherine
- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Belaid, Mohamed , Anaerobic , Co-digestion , Digester
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214100 , uj:21236 , Citation: Matheri, A.N. et al. 2016. Design model selection and dimensioning of anaerobic digester for the OFMSW.
- Description: Abstract: In this study, we investigated the design model selection and dimensioning of the anaerobic digester for the codigestion of different organics fraction of municipal solid waste (OFMSW) originating from the city’s landfills. The waste quantification and characterization exercise were undertaken at the point of generation, so as to obtain the total amount of waste generated and to ascertain the waste composition. Via the application of the simple multi-attribute rating (SMART) technique of multiple-criteria decision analysis (MCDA) as a decision support tool base on cost, scalability, temperature regulation, ease of construction, operation, and maintenance. The most preferred model option for bioenergy design technology was selected from a list of potential alternatives available in the market. Continuous stirred tank reactor (digester) CSTR scored the highest with 79% and was selected for the design in OFMSW biogas production. The geometry of the biodigester parameters was comparable with the anaerobic digestion (AD) process.
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- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Belaid, Mohamed , Anaerobic , Co-digestion , Digester
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214100 , uj:21236 , Citation: Matheri, A.N. et al. 2016. Design model selection and dimensioning of anaerobic digester for the OFMSW.
- Description: Abstract: In this study, we investigated the design model selection and dimensioning of the anaerobic digester for the codigestion of different organics fraction of municipal solid waste (OFMSW) originating from the city’s landfills. The waste quantification and characterization exercise were undertaken at the point of generation, so as to obtain the total amount of waste generated and to ascertain the waste composition. Via the application of the simple multi-attribute rating (SMART) technique of multiple-criteria decision analysis (MCDA) as a decision support tool base on cost, scalability, temperature regulation, ease of construction, operation, and maintenance. The most preferred model option for bioenergy design technology was selected from a list of potential alternatives available in the market. Continuous stirred tank reactor (digester) CSTR scored the highest with 79% and was selected for the design in OFMSW biogas production. The geometry of the biodigester parameters was comparable with the anaerobic digestion (AD) process.
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The role of trace elements on anaerobic codigestion in biogas production
- Matheri, Anthony Njuguna, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Jane Catherine
- Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Anaerobic digestion , Co-digestion , Mesophilic temperature , Trace elements
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93628 , uj:20371 , Citation: Matheri, A.N. et al. 2016. The role of trace elements on anaerobic codigestion in biogas production.
- Description: Abstract: In this study, we investigated the concentration of trace elements in the digestates in a laboratory batch anaerobic digester. Many of these trace elements are important macro and micro nutrients. The availability of these nutrients for microbes responsible for anaerobic digestion and substrate toxicity have to be controlled in biogas production. The analyzed substrates were characterized at various concentrations in the following trace elements; potassium, phosphorus, manganese, copper, calcium, molybdenum, zinc, cobalt, iron, aluminum, silver, nickel and cadmium. Trace elements like copper, silver, nickel, cadmium, zinc have been reported to be inhibitory and toxic under certain conditions in biochemical reaction depending on their concentrations. These trace elements lower biogas production above threshold concentration due to accumulation of organic acid as a result of methanogenic bacterial inhibition. There was no deficit of nutrients detected in the anaerobic digesters analysis.
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- Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Anaerobic digestion , Co-digestion , Mesophilic temperature , Trace elements
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93628 , uj:20371 , Citation: Matheri, A.N. et al. 2016. The role of trace elements on anaerobic codigestion in biogas production.
- Description: Abstract: In this study, we investigated the concentration of trace elements in the digestates in a laboratory batch anaerobic digester. Many of these trace elements are important macro and micro nutrients. The availability of these nutrients for microbes responsible for anaerobic digestion and substrate toxicity have to be controlled in biogas production. The analyzed substrates were characterized at various concentrations in the following trace elements; potassium, phosphorus, manganese, copper, calcium, molybdenum, zinc, cobalt, iron, aluminum, silver, nickel and cadmium. Trace elements like copper, silver, nickel, cadmium, zinc have been reported to be inhibitory and toxic under certain conditions in biochemical reaction depending on their concentrations. These trace elements lower biogas production above threshold concentration due to accumulation of organic acid as a result of methanogenic bacterial inhibition. There was no deficit of nutrients detected in the anaerobic digesters analysis.
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Mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings
- Matheri, Anthony Njuguna, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Catherine Jane, Mbohwa, Charles
- Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Catherine Jane , Mbohwa, Charles
- Date: 2016
- Subjects: Anaerobic digestion , Co-digestion , Mesophilic temperature
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214105 , uj:21240 , Citation: Matheri, A.N. et al. 2016. Mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings.
- Description: Abstract: The main focus of this study was mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings using pilot bio-digesters. The biochemical methane potential (BMP) works under batch anaerobic digester operating in ambient mesophilic temperature of 35 oC and 37 0C and pH of 7 to generate biogas. The carbon/nitrogen (C/N) ratio for cow dung and chicken droppings was found to be 17.70 and 63.67 respectively and grass clippings to be 20.54. Through co-digestion in a ratio of 1:1, the C/N ratio for cow dung and grass clippings settled at 19.19 while that for chicken droppings and grass clippings settled at 20.49. The conversion rate of the reaction and biogas production increased with the increase in temperature and hydraulic retention time until an equilibrium state was achieved. At the temperature 37 OC, it was observed to be the suitable mesophilic temperature for anaerobic digestion due to high dissociation and collision leading to high rate of biogas production.
- Full Text:
- Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Catherine Jane , Mbohwa, Charles
- Date: 2016
- Subjects: Anaerobic digestion , Co-digestion , Mesophilic temperature
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214105 , uj:21240 , Citation: Matheri, A.N. et al. 2016. Mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings.
- Description: Abstract: The main focus of this study was mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings using pilot bio-digesters. The biochemical methane potential (BMP) works under batch anaerobic digester operating in ambient mesophilic temperature of 35 oC and 37 0C and pH of 7 to generate biogas. The carbon/nitrogen (C/N) ratio for cow dung and chicken droppings was found to be 17.70 and 63.67 respectively and grass clippings to be 20.54. Through co-digestion in a ratio of 1:1, the C/N ratio for cow dung and grass clippings settled at 19.19 while that for chicken droppings and grass clippings settled at 20.49. The conversion rate of the reaction and biogas production increased with the increase in temperature and hydraulic retention time until an equilibrium state was achieved. At the temperature 37 OC, it was observed to be the suitable mesophilic temperature for anaerobic digestion due to high dissociation and collision leading to high rate of biogas production.
- Full Text:
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