Torrefaction of landfill food waste and characterization of the torrefied biomass
- Authors: Pahla, Godwell
- Date: 2016
- Subjects: Waste products as fuel , Renewable energy sources - Environmental aspects , Biomass energy , Renewable energy sources
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/243012 , uj:25081
- Description: M.Tech. (Chemical Engineering) , Abstract: Greenhouse gas emissions and municipal solid waste management have presented challenges globally. This study aims to help mitigate these challenges by producing renewable energy from landfill food waste. Food waste is carbon neutral since plants use carbon dioxide for growth, so its application in coal-fired boilers will reduce the amount of carbon dioxide emissions thereby mitigating greenhouse effects. The problem with food waste is that it has high moisture content and it is heterogeneous. This limits its heating value and increases energy requirements for grinding. This study investigated the possibility of upgrading the fuel properties of food waste to produce biochar with similar properties to bituminous coal. The food waste was treated by torrefaction. The main aim was to optimize torrefaction conditions and analyze thermal evolution of the sample during torrefaction. The food waste samples were collected from Marie Louis landfill site in Soweto. The samples were dried and milled for particle size reduction. The samples were further analyzed by proximate and ultimate analyses to determine its fuel properties and elemental composition before torrefaction. A tube furnace was used for the torrefaction process. Temperature was varied from 200 – 300 oC at a constant residence time of 40 min and 10 oC/min heating rate. Calorific value, mass yield, energy yield and energy density were computed and used to determine the appropriate torrefaction temperature. Residence time was then varied from 20 – 60 min at a constant torrefaction temperature of 275 oC and 10 oC/min heating rate. Heating rate was then varied keeping residence time at 20min and torrefaction temperature at 275 oC. Torrefaction temperature had a more pronounced effect than residence time and heating rate. The calorific value was upgraded from 19.76 MJ/kg for dried raw food waste to 26.15 MJ/kg for torrefied food waste at the optimum conditions which were 275 oC, 20 min and 10 oC/min. The higher heating value was comparable to that of bituminous coal currently being used for power generation in South Africa. Elemental analysis of biochar showed an increase in carbon content with temperature due to loss of oxygen containing volatiles. It was also observed that biochar obtained at the optimum conditions could easily be pelletized since it assumed the shape of the crucible...
- Full Text:
- Authors: Pahla, Godwell
- Date: 2016
- Subjects: Waste products as fuel , Renewable energy sources - Environmental aspects , Biomass energy , Renewable energy sources
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/243012 , uj:25081
- Description: M.Tech. (Chemical Engineering) , Abstract: Greenhouse gas emissions and municipal solid waste management have presented challenges globally. This study aims to help mitigate these challenges by producing renewable energy from landfill food waste. Food waste is carbon neutral since plants use carbon dioxide for growth, so its application in coal-fired boilers will reduce the amount of carbon dioxide emissions thereby mitigating greenhouse effects. The problem with food waste is that it has high moisture content and it is heterogeneous. This limits its heating value and increases energy requirements for grinding. This study investigated the possibility of upgrading the fuel properties of food waste to produce biochar with similar properties to bituminous coal. The food waste was treated by torrefaction. The main aim was to optimize torrefaction conditions and analyze thermal evolution of the sample during torrefaction. The food waste samples were collected from Marie Louis landfill site in Soweto. The samples were dried and milled for particle size reduction. The samples were further analyzed by proximate and ultimate analyses to determine its fuel properties and elemental composition before torrefaction. A tube furnace was used for the torrefaction process. Temperature was varied from 200 – 300 oC at a constant residence time of 40 min and 10 oC/min heating rate. Calorific value, mass yield, energy yield and energy density were computed and used to determine the appropriate torrefaction temperature. Residence time was then varied from 20 – 60 min at a constant torrefaction temperature of 275 oC and 10 oC/min heating rate. Heating rate was then varied keeping residence time at 20min and torrefaction temperature at 275 oC. Torrefaction temperature had a more pronounced effect than residence time and heating rate. The calorific value was upgraded from 19.76 MJ/kg for dried raw food waste to 26.15 MJ/kg for torrefied food waste at the optimum conditions which were 275 oC, 20 min and 10 oC/min. The higher heating value was comparable to that of bituminous coal currently being used for power generation in South Africa. Elemental analysis of biochar showed an increase in carbon content with temperature due to loss of oxygen containing volatiles. It was also observed that biochar obtained at the optimum conditions could easily be pelletized since it assumed the shape of the crucible...
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Reducing green house gas emmession by using renewables energy technology systems in South Africa
- Authors: Dlamini, Jama Dumsani
- Date: 2018
- Subjects: Greenhouse gas mitigation , Renewable energy sources - Environmental aspects , Electric power production , Climatic changes
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/269318 , uj:28610
- Description: Abstract: The renewable energy sector is growing at a very slow pace in South Africa. Renewable technology fraternity are a threat to the existing fossil fuelled energy sector. The economy of South Africa has traditionally been dependent mainly on fossil-fuelled energy sources (i.e coal, oil and gas) for producing electricity. The universe weather conditions have worsen due to damages caused by Greenhouse Gas Emissions (GHG) produced by fossil-fuelled energy sources. The earth planet is experiencing too much heat, drought and other hurricane life threatening disasters. The current population of the earth have a responsibility to minimise such pollutants for the sake of future generations. The demand for energy in South Africa compels the government to increase its electricity generation, while concurrently reducing Greenhouse Gas Emissions. Due to the above rationale a Renewable Energy Programme was introduced by South Africa in 2009 through the Department of Energy (DoE) partnered with private sector entities namely, the Development Bank of Southern Africa (DBSA) and the Independent Power Producers (IPP) office to form a Renewable Energy Programme known as the Renewable Energy Independent Power Producer Procurement Programme (REIPPPP). The REIPPPP has been praised by the international community as very successful as it has channelled substantial resources into renewable energy (RE) projects at competitive prices. The threat of Climate Change requires for consideration to switch to renewable energy resources that produce electricity without the emission of harmful greenhouse gases to the atmosphere. Environmental dilapidation affects us all, we need a healthy environment to live a healthy life, clean air and water, sage living areas, sufficient and healthy food. In August 1997, the Republic of South Africa joined the majority of countries in the international community in endorsement the United Nations Framework Convention on Climate Change (UNFCCC), which is the international framework aiming at addressing global warming. South Africa is a significant contributor of Greenhouse Gases Emissions, globally and far the highest emitter on the African Continent... , M.Phil. (Engineering Management)
- Full Text:
- Authors: Dlamini, Jama Dumsani
- Date: 2018
- Subjects: Greenhouse gas mitigation , Renewable energy sources - Environmental aspects , Electric power production , Climatic changes
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/269318 , uj:28610
- Description: Abstract: The renewable energy sector is growing at a very slow pace in South Africa. Renewable technology fraternity are a threat to the existing fossil fuelled energy sector. The economy of South Africa has traditionally been dependent mainly on fossil-fuelled energy sources (i.e coal, oil and gas) for producing electricity. The universe weather conditions have worsen due to damages caused by Greenhouse Gas Emissions (GHG) produced by fossil-fuelled energy sources. The earth planet is experiencing too much heat, drought and other hurricane life threatening disasters. The current population of the earth have a responsibility to minimise such pollutants for the sake of future generations. The demand for energy in South Africa compels the government to increase its electricity generation, while concurrently reducing Greenhouse Gas Emissions. Due to the above rationale a Renewable Energy Programme was introduced by South Africa in 2009 through the Department of Energy (DoE) partnered with private sector entities namely, the Development Bank of Southern Africa (DBSA) and the Independent Power Producers (IPP) office to form a Renewable Energy Programme known as the Renewable Energy Independent Power Producer Procurement Programme (REIPPPP). The REIPPPP has been praised by the international community as very successful as it has channelled substantial resources into renewable energy (RE) projects at competitive prices. The threat of Climate Change requires for consideration to switch to renewable energy resources that produce electricity without the emission of harmful greenhouse gases to the atmosphere. Environmental dilapidation affects us all, we need a healthy environment to live a healthy life, clean air and water, sage living areas, sufficient and healthy food. In August 1997, the Republic of South Africa joined the majority of countries in the international community in endorsement the United Nations Framework Convention on Climate Change (UNFCCC), which is the international framework aiming at addressing global warming. South Africa is a significant contributor of Greenhouse Gases Emissions, globally and far the highest emitter on the African Continent... , M.Phil. (Engineering Management)
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