The objective of this study is to restrict the emission of greenhouse gasses by investigating if this objective would be reached by the implementation of a tax. Global warming is caused by the emission of greenhouse gasses into the atmosphere. In order to restrict global warming it is necessary for individuals and entities to act in a more environmentally friendly manner and to emit less greenhouse gasses. A further objective of this study is to investigate various measures that can be used as an incentive to restrict the emission of greenhouse gasses. This study found that the main emitters of greenhouse gasses are power stations, industries and the transport sector. This study will therefore focus on the reduction of greenhouse gasses in these areas. The way to identify methods used to reduce greenhouse gas emissions, is to investigate the techniques that first world countries use to reduce greenhouse gas emissions, to judge the level of success they achieved and to compare their methods to the definition of a “good tax”. It was found that “cap-and-trade” is a better model than carbon tax for the reduction of greenhouse gas emissions by power stations and industries. It was also found that a combination between a tax on fuel and a tax calculated on greenhouse gas emissions per kilometre for each individual vehicle will result in the greatest reduction in the emission of greenhouse gasses produced by the transportation sector. AFRIKAANS : Die doelwit van hierdie studie is om die vrystelling van groenhuis uitlaatgasse te beperk deur ondersoek in te stel of die doelwit bereik kan word deur die implementering van 'n belasting. Globale aardverwarming word veroorsaak deur 'n oormaat vrystelling van groenhuisgasse in die atmosfeer. Om globale aardverwarming te beperk, sal individue, sowel as entiteite, meer omgewingsvriendelik moet optree deur minder groenhuisgasse vry te stel. 'n Verdere doelwit van hierdie studie is om verskeie metodes, insluitende belasting, te ondersoek waardeur die vrystelling van groenhuisgasse verminder kan word. In die studie is vasgestel dat kragstasies, industrieë en vervoerstelsels die hoofvrystellers van groenhuisgasse is. Die fokus van die studie is dus gerig op die vermindering van groenhuisgasvrystelling spesifiek in hierdie areas. Die wyse om metodes, wat gebruik word om groenhuisgasvrystellings te verminder, te identifiseer, is om die tegnieke wat in eerste wêreldlande gebruik word te ondersoek, om die vlak van sukses wat daarmee bereik word, te bepaal en om daardie metodes teen die definisie van 'n “goeie belasting” te toets. Daar is gevind dat “uitlaatgas handel” 'n beter model is as koolstofdioksiedbelasting ten einde 'n vermindering van groenhuisgasvrystellings deur kragstasies en industrieë te bewerkstellig. Daar is ook gevind dat ‘n kombinasie van ‘n belasting op brandstof en ‘n belasting bereken op groenhuisgasvrystellings per kilometer van elke individuele voertuig die grootste vermindering in groenhuisgasvrystellings in die vervoerstelsel sal meebring. Copyright / Dissertation (MCom)--University of Pretoria, 2010. / Taxation / unrestricted

Today, global warming is commonly known due to the major impact on the earth’s weather conditions. The increase in the average temperature of the lower atmosphere is causing a drastic change in weather conditions. Human intervention is the main cause of global warming and the latter will be limited if greenhouse gas (GHGs) emissions are reduced by individuals and companies in all countries around the world. Carbon dioxide (CO2) is one of the biggest contributors of GHGs and, therefore, a number of measures were implemented to reduce CO2 emissions. In 1997, the Kyoto Protocol was signed by the Annex 1 countries, of which South Africa is not part, under the United Nations Framework Convention on Climate Change (UNFCCC) to reduce GHG emissions. It is not only the responsibility of the Annex 1 countries to stabilise global warming, but all countries have to contribute to the reduction of GHG emissions. Enabling countries to meet these reduction targets, they implemented the following measures: carbon tax, Energy Service Companies (ESCOs) and carbon credits. Carbon tax has been implemented in many countries over the last decade with different levels of success. Carbon tax will be implemented in South Africa during 2013/2014. ESCOs have been implemented to assist companies with the implementation of energy saving projects. These projects will assist in reducing carbon emissions and meeting the set targets and it will also assist in reducing the effect of carbon tax. Clean Development Mechanism (CDM) projects are implemented under the UNFCCC for companies that want to register carbon reduction projects. If the projects meet the CDM registration criteria, the project can be registered as a CDM project and it has the ability to earn tradable carbon credits. These credits can be traded on national or international carbon trading markets. This study considered a combination of all the measures a company can implement to improve energy efficiency and thereby reducing GHG emissions. An evaluation of the feasibility of a carbon reduction project, the ‘Vaal River compressed air energy efficiency improvement project’ of AngloGold Ashanti (AGA) was performed to determine whether the project can be registered as a CDM project. It was concluded that AGA will be able to register the project as a CDM project and earn tradable carbon credits. Furthermore, it is recommended that AGA makes use of the option to finance the carbon reducing project by using external funding provided by EDF (the French equivalent of South Africa’s Eskom). / MCom (Management Accountancy)), North-West University, Potchefstroom Campus, 2013

Today, global warming is commonly known due to the major impact on the earth’s weather conditions. The increase in the average temperature of the lower atmosphere is causing a drastic change in weather conditions. Human intervention is the main cause of global warming and the latter will be limited if greenhouse gas (GHGs) emissions are reduced by individuals and companies in all countries around the world. Carbon dioxide (CO2) is one of the biggest contributors of GHGs and, therefore, a number of measures were implemented to reduce CO2 emissions. In 1997, the Kyoto Protocol was signed by the Annex 1 countries, of which South Africa is not part, under the United Nations Framework Convention on Climate Change (UNFCCC) to reduce GHG emissions. It is not only the responsibility of the Annex 1 countries to stabilise global warming, but all countries have to contribute to the reduction of GHG emissions. Enabling countries to meet these reduction targets, they implemented the following measures: carbon tax, Energy Service Companies (ESCOs) and carbon credits. Carbon tax has been implemented in many countries over the last decade with different levels of success. Carbon tax will be implemented in South Africa during 2013/2014. ESCOs have been implemented to assist companies with the implementation of energy saving projects. These projects will assist in reducing carbon emissions and meeting the set targets and it will also assist in reducing the effect of carbon tax. Clean Development Mechanism (CDM) projects are implemented under the UNFCCC for companies that want to register carbon reduction projects. If the projects meet the CDM registration criteria, the project can be registered as a CDM project and it has the ability to earn tradable carbon credits. These credits can be traded on national or international carbon trading markets. This study considered a combination of all the measures a company can implement to improve energy efficiency and thereby reducing GHG emissions. An evaluation of the feasibility of a carbon reduction project, the ‘Vaal River compressed air energy efficiency improvement project’ of AngloGold Ashanti (AGA) was performed to determine whether the project can be registered as a CDM project. It was concluded that AGA will be able to register the project as a CDM project and earn tradable carbon credits. Furthermore, it is recommended that AGA makes use of the option to finance the carbon reducing project by using external funding provided by EDF (the French equivalent of South Africa’s Eskom). / MCom (Management Accountancy)), North-West University, Potchefstroom Campus, 2013

With the increasing global energy demand and the decreasing availability of good quality coals, a better understanding of the important properties that control the behaviour of low–grade coals and the subsequent chars in various utilisation processes, becomes pertinent. An investigation was therefore undertaken, to study the effects of chemical and physical properties imparted on chars during pyrolysis on the subsequent gasification reaction kinetics of typical South African inertinite–rich, high ash Highveld coals. An attempt was made at following these changes in the transition from coals to chars by a detailed characterisation of both the parent coals and the respective chars. These changes were determined using various conventional and advanced techniques, which included among others, carbon crystallite analysis using XRD and char carbon forms analysis using petrography. Three of the four original coals were characterised as Bituminous Medium rank C (coals B, C and C2), while coal D2 was found to be slightly lower in rank (Bituminous Medium rank D). The coals were rich in inertinites (> 54 vol. %, mmb with coal C2 having as high as 79 vol. %, mmb) and high in ash content (> 26.7 wt. %, db) and cabominerite and minerite contents (26 – 39 vol. %, mmb). The inertinitevitrinite ratios of the coals were found to range from 1.93 to 26.3. Characterization results show that both volatile matter and inherent moisture content decreased, while ash, fixed carbon and elemental carbon contents increased from coals to chars, indicating that the pyrolysis process was efficient. Elemental hydrogen, oxygen and nitrogen contents decreased, whereas total sulphur contents increased from coals to chars. This reveals that the total sulphur contained in the char samples was associated with the char carbon matrix and the minerals. Hydrogen–carbon and oxygen–carbon ratios decreased considerably from coals to chars showing that the chars are more aromatic and denser products than the original coals. Despite the fact that mineral matter increased from coals to chars, the relative abundance of the different mineral phases and ash components did not exhibit significant variation amongst the samples. The alkali index was, however, found to vary considerably among the subsequent chars. Petrographic analysis of the coals and char carbon forms analysis of the chars reveal that total reactive components (TRC) decrease while the total inert components (TIC) increase from coals to chars. The 0% gain in TIC observed in char C2 was attributed to its relatively high partially reacted maceral char carbon forms content. Total maceral reflectance shifted to higher values in the chars (4.43 – 5.28 Rsc%) relative to the coals (1.15 – 1.63 Rsc%) suggesting a higher structural ordering in the chars. Carbon crystallite analyses revealed that the chars were condensed (smaller in size) relative to the parent coals. Lattice parameters: interlayer spacing, d002, increased, while the average crystallite height, Lc, crystallite diameter, La, and number of aromatic layers per crystallite, Nave, decreased from coals to chars. Carbon aromaticity generally increased whereas the fraction of amorphous carbon and the degree of disorder index decreased from parent coals to the respective chars. Both micropore surface area and microporosity were observed to increase while the average micropore diameter decreased from coals to chars. This shows that blind and closed micropores were “opened up” during the charring process. Despite the original coal samples not showing much variation in their properties (except for their maceral content), it was generally observed that the subsequent chars exhibited substantial differences, both amongst themselves and from the parent coals. The increasing orders of magnitude of micropore surface area, microporosity, fraction of amorphous carbon and structural disorderliness were found to change in the transition, a good indication that the chars’ properties varied from that of the respective parent coals. Isothermal CO2 gasification experiments were conducted on the chars in a Thermax 500 thermogravimetric analyser in the temperature range of 900 – 950 °C with varying concentrations of CO2 (25 – 100 mol. %) in the CO2–N2 reaction gas mixture at ambient pressure (0.875 bar in Potchefstroom). The effects of temperature and CO2 concentration were observed to be in conformity with established trends. The initial reactivity of the chars was found to increase in the order: chars C2 < C < B < D2, with char D2 reactivity greater than the reactivity of the other chars by a factor > 4. Gasification reactivity results were correlated with properties of the parent coals and chars. Except for the rank parameter (the vitrinite reflectance), no significant trend was observed with any other coal petrographic property. Correlations with char properties gave more significant and systematic trends. Major factors affecting the gasification reactivity of the chars as it pertains to this investigation are: parent coal vitrinite reflectance, and: aromaticity, fraction of amorphous carbon, degree of disorder and alkali indices, micropore surface area, microporosity and average micropore diameter of the chars. The random pore model (chemical reaction controlling) was found to adequately describe the gasification reaction experimental data (both conversions and conversion rates). The determined activation energy ranged from 163.3 kJ·mol–1 for char D2 to 235.7 kJ·mol–1 for char B; while the order of reaction with respect to CO2 concentration ranged between 0.52 to 0.67 for the four chars. The lower activation energy of char D2 was possibly due to its lower rank, lower coal vitrinite reflectance and higher alkali index. The estimated kinetic parameters of the chars in this study correspond very well with published results in open literature. It was possible to express the intrinsic reactivity, rs, of the chars (rate of carbon conversion per unit total surface area) using kinetic results, in empirical Arrhenius forms. / Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2011.

With the increasing global energy demand and the decreasing availability of good quality coals, a better understanding of the important properties that control the behaviour of low–grade coals and the subsequent chars in various utilisation processes, becomes pertinent. An investigation was therefore undertaken, to study the effects of chemical and physical properties imparted on chars during pyrolysis on the subsequent gasification reaction kinetics of typical South African inertinite–rich, high ash Highveld coals. An attempt was made at following these changes in the transition from coals to chars by a detailed characterisation of both the parent coals and the respective chars. These changes were determined using various conventional and advanced techniques, which included among others, carbon crystallite analysis using XRD and char carbon forms analysis using petrography. Three of the four original coals were characterised as Bituminous Medium rank C (coals B, C and C2), while coal D2 was found to be slightly lower in rank (Bituminous Medium rank D). The coals were rich in inertinites (> 54 vol. %, mmb with coal C2 having as high as 79 vol. %, mmb) and high in ash content (> 26.7 wt. %, db) and cabominerite and minerite contents (26 – 39 vol. %, mmb). The inertinitevitrinite ratios of the coals were found to range from 1.93 to 26.3. Characterization results show that both volatile matter and inherent moisture content decreased, while ash, fixed carbon and elemental carbon contents increased from coals to chars, indicating that the pyrolysis process was efficient. Elemental hydrogen, oxygen and nitrogen contents decreased, whereas total sulphur contents increased from coals to chars. This reveals that the total sulphur contained in the char samples was associated with the char carbon matrix and the minerals. Hydrogen–carbon and oxygen–carbon ratios decreased considerably from coals to chars showing that the chars are more aromatic and denser products than the original coals. Despite the fact that mineral matter increased from coals to chars, the relative abundance of the different mineral phases and ash components did not exhibit significant variation amongst the samples. The alkali index was, however, found to vary considerably among the subsequent chars. Petrographic analysis of the coals and char carbon forms analysis of the chars reveal that total reactive components (TRC) decrease while the total inert components (TIC) increase from coals to chars. The 0% gain in TIC observed in char C2 was attributed to its relatively high partially reacted maceral char carbon forms content. Total maceral reflectance shifted to higher values in the chars (4.43 – 5.28 Rsc%) relative to the coals (1.15 – 1.63 Rsc%) suggesting a higher structural ordering in the chars. Carbon crystallite analyses revealed that the chars were condensed (smaller in size) relative to the parent coals. Lattice parameters: interlayer spacing, d002, increased, while the average crystallite height, Lc, crystallite diameter, La, and number of aromatic layers per crystallite, Nave, decreased from coals to chars. Carbon aromaticity generally increased whereas the fraction of amorphous carbon and the degree of disorder index decreased from parent coals to the respective chars. Both micropore surface area and microporosity were observed to increase while the average micropore diameter decreased from coals to chars. This shows that blind and closed micropores were “opened up” during the charring process. Despite the original coal samples not showing much variation in their properties (except for their maceral content), it was generally observed that the subsequent chars exhibited substantial differences, both amongst themselves and from the parent coals. The increasing orders of magnitude of micropore surface area, microporosity, fraction of amorphous carbon and structural disorderliness were found to change in the transition, a good indication that the chars’ properties varied from that of the respective parent coals. Isothermal CO2 gasification experiments were conducted on the chars in a Thermax 500 thermogravimetric analyser in the temperature range of 900 – 950 °C with varying concentrations of CO2 (25 – 100 mol. %) in the CO2–N2 reaction gas mixture at ambient pressure (0.875 bar in Potchefstroom). The effects of temperature and CO2 concentration were observed to be in conformity with established trends. The initial reactivity of the chars was found to increase in the order: chars C2 < C < B < D2, with char D2 reactivity greater than the reactivity of the other chars by a factor > 4. Gasification reactivity results were correlated with properties of the parent coals and chars. Except for the rank parameter (the vitrinite reflectance), no significant trend was observed with any other coal petrographic property. Correlations with char properties gave more significant and systematic trends. Major factors affecting the gasification reactivity of the chars as it pertains to this investigation are: parent coal vitrinite reflectance, and: aromaticity, fraction of amorphous carbon, degree of disorder and alkali indices, micropore surface area, microporosity and average micropore diameter of the chars. The random pore model (chemical reaction controlling) was found to adequately describe the gasification reaction experimental data (both conversions and conversion rates). The determined activation energy ranged from 163.3 kJ·mol–1 for char D2 to 235.7 kJ·mol–1 for char B; while the order of reaction with respect to CO2 concentration ranged between 0.52 to 0.67 for the four chars. The lower activation energy of char D2 was possibly due to its lower rank, lower coal vitrinite reflectance and higher alkali index. The estimated kinetic parameters of the chars in this study correspond very well with published results in open literature. It was possible to express the intrinsic reactivity, rs, of the chars (rate of carbon conversion per unit total surface area) using kinetic results, in empirical Arrhenius forms. / Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2011.