Sasol Infragas uses various maintenance information systems that support operational and maintenance personnel in their everyday environment. These systems have been in operation for more than two years. Currently, there are four maintenance information systems in use at Infragas, these are; alarm management, deviation management, overall efficiency management, and rotating equipment management. The information from these systems is stored on intranet portals which are accessible to all Infragas employees. This paper aimed to analyse the extent to which these portals are being utilised by Infragas employees, if at all. This paper also investigated the employees’ mind-set towards the maintenance information systems. This will assist in understanding which systems enhancements can be made to further improve employee engagement. These objectives were achieved by means of two methods. The first method was an actual usage measurement. This identified which employees were using the portals, as well as the usage frequency. This investigation method gave a real indication of the system usage and highlighted any shortfalls in employees’ interaction with the portals. The second method was a questionnaire, given to Infragas employees. The first section analysed whether the Infragas maintenance information systems are an accepted technology by investigating whether systems are being used by portal users. This was done by means of a technology acceptance model. The questionnaire also aimed to gather information on portal quality characteristics. This would indicate which quality characteristics are important to Infragas employees. Maintenance information system quality needs will differ from employee to employee. This information could improve the quality of interaction between the employees and the portals. The questionnaire also aimed to examine employees’ attitudes towards maintenance information systems. This section investigated whether employees felt that maintenance information systems improved plant performance and were beneficial to the Infragas environment. These investigations revealed valuable information for the improvement of these systems. The connection between the results of the two methods also indicated if both methods were valid. The information gathered from this study was communicated back to the Sasol Infragas management team. Recommendations for possible system improvements, which would increase employee system interaction, were also made. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014

Sasol Infragas uses various maintenance information systems that support operational and maintenance personnel in their everyday environment. These systems have been in operation for more than two years. Currently, there are four maintenance information systems in use at Infragas, these are; alarm management, deviation management, overall efficiency management, and rotating equipment management. The information from these systems is stored on intranet portals which are accessible to all Infragas employees. This paper aimed to analyse the extent to which these portals are being utilised by Infragas employees, if at all. This paper also investigated the employees’ mind-set towards the maintenance information systems. This will assist in understanding which systems enhancements can be made to further improve employee engagement. These objectives were achieved by means of two methods. The first method was an actual usage measurement. This identified which employees were using the portals, as well as the usage frequency. This investigation method gave a real indication of the system usage and highlighted any shortfalls in employees’ interaction with the portals. The second method was a questionnaire, given to Infragas employees. The first section analysed whether the Infragas maintenance information systems are an accepted technology by investigating whether systems are being used by portal users. This was done by means of a technology acceptance model. The questionnaire also aimed to gather information on portal quality characteristics. This would indicate which quality characteristics are important to Infragas employees. Maintenance information system quality needs will differ from employee to employee. This information could improve the quality of interaction between the employees and the portals. The questionnaire also aimed to examine employees’ attitudes towards maintenance information systems. This section investigated whether employees felt that maintenance information systems improved plant performance and were beneficial to the Infragas environment. These investigations revealed valuable information for the improvement of these systems. The connection between the results of the two methods also indicated if both methods were valid. The information gathered from this study was communicated back to the Sasol Infragas management team. Recommendations for possible system improvements, which would increase employee system interaction, were also made. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014

Thesis (PhD)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The analysis of Fischer–Tropsch–derived (FT–derived) synthetic crude and derived products is very challenging because of the highly complex nature of these products. In this study, the use of comprehensive multidimensional gas chromatography (GCxGC) with time-of-flight mass spectrometry (TOF-MS) and flame ionisation detection (FID) was investigated for the analysis of these products and the technique was found to be invaluable for the analysis of these complex mixtures. The compositions of FT synthetic crude, produced at low temperature (LT–FT) and high temperature (HT–FT) processes were compared and the effect that changes in FT reaction temperature has on product formation was investigated. Results for conventional onedimensional GC (1D-GC) and GCxGC were compared. It was found that conventional 1D–GC does not have sufficient peak capacity to separate the thousands of compounds in the HT FT products. GCxGC provides a huge peak capacity of tens-of-thousands to separate highly complex mixtures. Structured chromatograms, where groups of compounds with similar properties are grouped together, aid in peak identification. Moreover, sensitivity at low microgram per milliliter levels is obtained. These attributes enabled accurate analysis of various complex feed and product streams in the FT refinery, and also various final fuel products. The use of GCxGC alone was demonstrated, and also combined with high performance liquid chromatography (HPLC), supercritical fluid chromatography (SFC) and nuclear magnetic resonance (NMR) when even more separation power was needed. HPLC–GCxGC enabled the separation of alkene and cyclic alkane compound classes in oligomerisation products. These compound classes have similar mass spectra, elute in adjacent regions and co–elute even to some extent on the GCxGC contour plot, making differentiation difficult. SFC is a good replacement for HPLC for these applications because it does not use solvents as mobile phases. CO2 is easily evaporated after the separation and does not interfere with the GCxGC separation of the analytes. SFC is also a very good technique to separate the compound classes of alkanes, alkenes, aromatics and oxygenates, and is therefore highly complementary to GCxGC. The combination of GCxGC with NMR data was also found to be very valuable for the identification of branched alkane isomers in LT–FT diesels. GCxGC provides excellent separation of individual compounds but the identification of isomers (except for mono–methyl branching) is difficult because the mass spectra of most of these isomers are similar and not all compounds are in the mass spectral libraries. NMR, on the other hand, is able to distinguish between the individual types of branched isomers but has limited separation power for the complex mixtures. By combining the two techniques, the best of both was obtained. The study found GCxGC to be invaluable for the analysis of the highly complex FT–derived products, while its combination with other techniques such as HPLC, SFC and NMR provided even more separation power. / AFRIKAANSE OPSOMMING: Die hoogs komplekse samestelling van sintetiese ru–olie en afgeleide produkte, afkomstig van Fischer–Tropsch (FT) sintese, bied groot uitdagings aan die analis. Die studie het die gebruik van GCxGC met ’n TOF-MS en FID bestudeer vir die analise van FT produkte en het bevind dat die tegniek van onskatbare waarde is vir die analise van die hoogs komplekse mengsels. Die samestellings van produkte van lae- en hoë-temperatuur FT prossesse is vergelyk en die effek van ’n verhoging in die reaksie–temperatuur op die produk samestelling is ondersoek. Resultate vir 1D–GC and GCxGC is vergelyk en dit was duidelik dat 1D-GC nie naastenby voldoende piekkapasiteit het om al die komponente van die produkte wat tydens die hoëtemperatuur prosses gevorm word, te kan skei nie. Die GCxGC se piekkapasiteit daarteenoor is in die orde van tienduisende wat die skeiding van hoogs komplekse mensels moontlik maak terwyl die tegniek hoogs gestruktureerde kontoerplotte verskaf wat help met identfikasie van komponente. Die tegniek is verder ook baie sensitief en kan komponente op lae μg/mL vlakke waarneem. Hierdie eienskappe het akkurate analise van verskeie FT produkstrome moontlik gemaak. Die kombinasie van GCxGC met HPLC, SFC en KMR het selfs meer skeidingskrag verskaf waar nodig. HPLC–GCxGC het die skeiding van alkene en sikliese alkane moontlik gemaak. Hierdie komponent klasse se massaspektra is feitlik dieselfde en terselfdertyd elueer die twee groepe reg langs mekaar, en oorvleuel soms selfs tot ’n mate, op die GCxGC kontoerplot, sodat dit moeilik is om daartussen te onderskei. SFC is ’n goeie alternatief vir HPLC in meeste toepassings aangesien die tegniek net CO2 gebruik, wat maklik verdamp by kamertemperatuur en nie oplosmiddels gebruik wat se pieke steur met die van die laekookpunt komponente op die GCxGC kontoerplot nie. Skeidings van die komponentgroepe alkane, alkene, aromate en oksigenate is moontlik met SFC en daarom komplimenteer dit die GCxGC skeiding goed aan. Die kombinasie van GCxGC met kern–magnetiese resonansie (KMR) is van waarde gevind om die verskillende tipes vertakkings in ’n lae-temperatuur FT diesel te identifiseer. GCxGC verskaf uitstekende skeiding van individuele komponente maar die identifikasie van die verskilende isomere, behalwe vir die mono-metiel vertakkings, is moeilik aangesien die massaspektra van baie van die komponente soortgelyk is en die komponente nie in die massa spektrum–biblioteke voorkom nie. KMR, aan die ander kant, kan tussen die individuele vertakkings onderskei maar het beperkte skeidingskrag vir komplekse mensels. Deur die twee tegnieke te kombineer is die beste van albei tegnieke bekom. Die studie het bevind dat GCxGC van onskatbare waarde is vir die analise van die komplekse sintetiese FT produkte terwyl die kombinasie met ander tegnieke soos HPLC, SFC and KMR selfs meer skeidingskrag verskaf.

Fornos petroquímicos constituem a parte mais importante da indústria de derivados de petróleo. São nesses fornos que se processam as reações químicas imprescindíveis ao processamento dos produtos que constituem nosso cotidiano, como os fertilizantes, polímeros, produtos farmacêuticos e alimentícios. Devido ao caráter fortemente endotérmico dos processos, associado a reações catalíticas provocada numa mistura reacional de vapor de água com hidrocarbonetos (caso da reforma para obtenção de hidrogênio) ou craqueamento por pirólise (processo de pirólise), estes fornos são continuamente aquecidos. Com o objetivo de aumento de produção e produtividade, os fornos têm sido submetidos a condições de temperatura e pressão cada vez mais extremas. Nos fornos de pirólise, adicionalmente tem-se aumentado consideravelmente a velocidade do fluido e para tanto têm tido as seções transversais dos condutos diminuídas levando a um aumento das tensões de trabalho. Além disso, paradas e partidas desses fornos têm se mostrado um elemento crucial na operação. É comum que durante a parada desses fornos se detecte fragilização desse material após certo tempo de serviço à temperatura de trabalho. Quedas significativas nos valores de alongamento têm sido reportadas sendo que em algumas situações, componentes apresentam valores nulos de alongamento à temperatura ambiente quando ensaios mecânicos são efetuados em corpos de prova retirados dos mesmos. Devido a essa fragilização, com conseqüente diminuição nos valores de alongamento, operações de reparo por soldagem têm se mostrado freqüentemente impraticáveis resultando no sucateamento do componente. Nesse trabalho caracterizou-se a fragilização ocorrida no material 20Cr32Ni+Nb que é usado nos coletores de saída de fornos que embora operem em temperaturas mais baixas, estão sujeitos também aos mesmos requisitos de pressão do forno. Para melhor caracterizar o material em estudo, um tubo centrifugado foi analisado tomando-se o cuidado de extrair corpos de prova em regiões que propiciassem microestrutura reprodutível. Para garantir que os corpos de prova fossem submetidos a temperaturas e tempos similares com boa precisão, estes foram envelhecidos em equipamento de ensaios de fluência, porém sem aplicação de tensão. Os corpos de prova envelhecidos foram então ensaiados com tração à temperatura ambiente e o alongamento da fratura foi registrado, evidenciando a fragilização. A região da cabeça do corpo de prova foi examinada por metalografia óptica e por microscópio eletrônico de varredura (MEV). As fraturas foram igualmente examinadas no microscópio eletrônico de varredura. Os resultados obtidos na microscopia ótica, com e sem ataque, bem como no MEV não evidenciaram quaisquer alterações microestruturais significativas que justificassem a alteração do comportamento mecânico com o envelhecimento. Análises fratográficas também não evidenciaram alteração significativa no mecanismo de fratura que ocorre pela nucleação de micro-cavidades (dimples). Adicionalmente procurou-se comprovar ou rejeitar a hipótese de que a fragilização seria causada ela precipitação de um intermetálico frágil em contorno de grão: a chamada fase G (um silicieto misto de nióbio e níquel com estequiometria Ni16Nb6Si7, estrutura cúbica de faces centradas e parâmetro de rede a0 = 1,13nm). A análise dos resultados não evidencia fase nova, nem uma mudança de modo de fratura de trans para intergranular, que poderiam comprovar uma influência da fase G no processo de fragilização (ao menos até o limite de resolução das técnicas experimentais aqui empregadas). / Petrochemical furnaces play an important role in the oil industry. In these furnaces, the essential chemical reactions take place in order to get everyday products like fertilizers, polymers, products for pharmaceutic and food industry. Due to the highly endothermic characteristics of these processes, these furnaces are heated up. It is common during shutdowns and startups of these furnaces, to have fragilization of this material after an aging time at working temperatures. This fragilization impairs repair when needed. In order to have an increase in production and productivity, the furnaces are continuously submitted to higher temperature and pressure working conditions. Pyrolisis furnaces have been also subjected to an increase in fluid speed and in order to reach this, the transverse area of tubes has been significantly decreased resulting in an increase in working stresses. Besides, shutdowns and startups have been a crucial part of operation. Fragilization in this material in service at high temperatures is frequently detected during shutdowns. Significant losses in elongation have been reported and sometimes components show no elongation at room temperature when samples are subjected to tensile testing. Due to this fragilization and low elongation values, repair by welding is sometimes useless resulting in scrapping the component. In this work the characterization of the fragilization that occurs in a 20Cr32Ni+Nb centrifugally cast tube, whose application is the outlet collectors that, though operate in lower temperature, are subjected to the pressure requirements of the furnace. In order to better characterize the material, one centrifugally cast tube was analysed taking care of having the test samples from regions that could provide similar microstructures. In order to assure that the samples were submitted to temperature and time with good accuracy, they were aged in a creep testing machine, but without application of load. The aged samples were then tensile tested at room temperature and the fracture elongation was calculated, evidencing the fragilization. The head of the test sample was examined by optical metalography and Scanning Electron Microscopy (SEM). The fractured areas were also examined by SEM. The results from optical microscopy, with or without etching, as well as SEM did not show any microstructural changes that could explain the changes in mechanical behavior with during aging. Additionally one aims to confirm or reject the hypothesis of the fragilization being caused by the precipitation of an fragile intermetallics in the grain boundary: the socalled G-phase (a silicide of Niobium and Nickel with stoichiometry Ni16Nb6Si7 , face centered cubic and lattice parameter of a0 = 1,13nm). The results did not either evidence this new phase nor a change in the fracture mode from trans to intergranular which could confirm the influence of this phase in the fragilization process (at least in the resolution limits of the experimental procedures here employed).

Made available in DSpace on 2015-03-05T19:12:38Z (GMT). No. of bitstreams: 0 Previous issue date: 20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Com o crescente interesse mundial e com a conscientização de que as organizações e os órgãos governamentais devem desempenhar um papel importante no âmbito do desenvolvimento sustentável, várias normas e recomendações de disclosure ambiental estão sendo editadas. Alguns organismos internacionais ligados à área contábil, tais como o Intergovernmental Working Group of Experts on International Standards of Accounting and Reporting (ISAR/UNCTAD) e a International Federation of Accountants (IFAC), têm dedicado atenção às informações contábeis relativas à sustentabilidade ambiental. Da mesma forma, nos Estados Unidos da América e no Brasil, alguns organismos têm emitido normativas relacionadas ao registro contábil e à publicação de informes ambientais. Tais normativas estão relacionadas tanto com a identificação quanto a evidenciação das informações de natureza ambiental nos relatórios anuais das companhias. Nesse contexto, o presente estudo, de caráter exploratório, visa a avaliar o nível de aderência de uma amost / With the growing worldwide interest and awareness of organizations and government organs that have an important role in the area of sustainable development, various standards and recommendations for environmental information disclosure are being issued. Some international entities connected to accounting, such as the Intergovernmental Working Group of Experts on International Standards of Accounting and Reporting (ISAR/UNCTAD) and the International Federation of Accountants (IFAC), have turned their attention to accounting information that relates to environmental sustainability. In the same way, in United States of America and Brazil some entities have issued standards for account recording and publication of environmental information. These standards relate both to identification and environmental nature information reporting in annual corporate reports. In this context, this exploratory study seeks to evaluate the degree of conformance of a sample of 10 (ten) companies in chemical and petrochemical sector,

A Teoria dos Jogos é amplamente utilizada no estudo de fenômenos de interação estratégica, em especial na análise de mercados de commodities. Esse trabalho faz uma análise preliminar do mercado brasileiro de eteno e propeno sob a ótica de um modelo baseado na Teoria dos Jogos, representado matematicamente através de um problema de complementaridade mista. Neste modelo, as empresas atuam em uma competição de Cournot e os custos de produção são parâmetros incertos, representados através de cenários, sendo que, no equilíbrio, três decisões devem ser tomadas: i) o portifólio de tecnologias para produção, ii) a capacidade de produção de cada tecnologia e iii) o nível de produção de cada tecnologia em cada cenário. Considerando as diversas limitações do estudo, as simulações realizadas com o modelo proposto mostram que o comportamento dos agentes da indústria petroquímica brasileira está mais próximo de tomadores de preços, sem possibilidade de regulação de preços através das quantidades produzidas. / Game Theory is widely used in the study of strategic interaction, especially in the analysis of commodity markets. This work makes a preliminary analysis of the Brazilian ethylene and propylene market from the perspective of a model based on game theory, represented mathematically by a mixed complementarity problem. In this model, firms behave as Cournot players and production costs are uncertain parameters, represented by scenarios, and in equilibrium three decisions must be made: i) the portfolio of technologies for production, ii) technologies capacity and iii) the level of production for each technology in each scenario. Considering the limitations of the study, the simulations carried out with the proposed model show that the behavior of the Brazilian petrochemical industry agents is closer to price takers, without possibility of price regulation by the quantities produced.

Na presente dissertação, o setor petroquímico é utilizado como mote para um estudo sobre os contornos do direito antitruste nacional, sua interpretação e aplicação à luz das especificidades da economia brasileira. O pano de fundo deste trabalho é o debate, levantado durante os anos 1990, sobre a disciplina da concorrência nos países em desenvolvimento dever ou não seguir as tendências mais contemporâneas das instituições de países de economia mais avançada e com tradição na matéria antitruste. Além da revisão dos conceitos e práticas da regulação da concorrência nos países centrais (e de alguns dos desafios apontados pela literatura acerca da sua aplicação em economias em desenvolvimento), são descritos os traços gerais atribuídos a esse ramo do direito, no ordenamento jurídico brasileiro, focalizando as disposições referentes ao controle das estruturas de mercado. Para contextualizar a pesquisa empírica sobre os atos de concentração apreciados pela autoridade de defesa da concorrência (Conselho Administrativo de Defesa da Concorrência - CADE) envolvendo a petroquímica, abordam-se as características do setor e a trajetória da atuação estatal nesse ramo. Os resultados encontrados apontam que o direito da concorrência complementa, mas não substitui outros instrumentos de política pública necessários à coordenação dos mercados e à promoção de sua competitividade, os quais são especialmente relevantes para as economias em desenvolvimento. / In this study, petrochemical industry plays the framework for the research about the boundaries of Brazilian competition law, its interpretation and application in the light of the singularities of Brazilian economy. This subject is concerned with the debate raised during the 1990\'s about the adequacy of the model of competition law and policy advocated by advanced economies for developing countries. In addition of revising the leading concepts and practices on competition law, the main features of Brazilian antitrust law are also described, focusing on the provisions for the control of mergers and acquisitions. With the aim of contextualizing the empirical research about the cases entailing petrochemical firms submitted to the Brazilian Competition Law Council, the characteristics of this industry and the role of public regulation in this field are approached. The results obtained indicate that competition law complements, but does not substitute other instruments of public policy, which are necessary to market coordination and industrial competitiveness. These policies are especially important for the economies of developing countries.

The aim of this thesis is to explore the diversification of a major oil company into the. petrochemical business and then through thorough analysis to recommend the appropriate corporate strategies to be followed by the petrochemical subsidiary of such a company in the 1980's and the 1990's. The petrochemical industry has undergone great changes during the last decade. In the early 1970's it entered a new era of maturity, however due to the misplannings of the late 1960's extending to the early 1970's the industry was suddenly faced with significant overcapacity which has persisted to the present date and is expected to last well into the 1980's. The 1974 oil crisis caused a further decline in the growth of demand, hence exacerbating the situation. During the seventies the industry has had to operate under increasing material prices, unlike the past, which when coupled with the problem of overcapacity and the resulting deterioration of prices, has caused considerable decline in the financial ability of the companies to finance their capital expenditure programmes through internal cash generation (which was the case in the industry's 'golden era'). This situation is threatening the long term viability and survival of the petrochemical businesses. A System Dynamics model for a hypothetical petrochemical subsidiary of a major oil company has been constructed which embodies all the policies inherent in such a system. The dynamic behaviour of the model closely resembles that expected from the real system such as the declining financial ability, which is mostly due to the inflationary conditions. Through thorough analysis, the impact of varying inflation level on the performance of the system was explored, and the need for adopting suitable accounting policies which would take account of the replacement costs of assets, during periods of high inflation, was proposed. The adoption of a number of policies led to a certain degree of improvement in the financial performance of the system, and these are recommended concerning the corporate strategy of the company for the next two decades. Finally it was discovered that due to the low level of growth of demand (compared to the past), the large economic sizes of the petrochemical plants and the market share consensus, the companies will have to go into joint ventures in the future.

Reaction water, a high-strength COD (chemical oxygen demand) petrochemical effluent, is generated during the Fischer-Tropsch reaction in the SASOL Synthol process at SASOL SynFuels, Secunda, South Africa. Distillation of the reaction water to remove non- and oxygenated hydrocarbons yields approximately 25 - 30 ML/d of an organic (carboxylic) acid-enriched stream (average COD of 16 000 mg/L) containing primarily C2 – C5 organic acids, light oils, aldehydes, ketones, cresols and phenols. Together with the Oily sewer water (API) and Stripped Gas Liquor (SGL) process streams, this process effluent is currently treated in ten dedicated activated sludge basins. However, the successful operation of these activated sludge systems has proven to be difficult with low organic loading rates (3.5 kg COD/m3.d) low COD removal efficiencies (<80 %) and high specific air requirements (60 - 75 m3 air/kg CODrem). It is hypothesised that these operational difficulties can be attributed to organic shock loadings, variation in volumetric and hydraulic loadings, as well as variations in the composition of the various process streams being treated. Due to the fact that the Fischer-Tropsch (Synthol) reaction water constitutes 70 % of the COD load on the activated sludge systems, alternative processes to improve the treatment cost and efficiency of the Fischer-Tropsch acid stream are being investigated. Various studies evaluating the aerobic and anaerobic treatment of Fischer-Tropsch reaction water alone in suspended growth wastewater treatment systems have proven unsuccessful. High rate fixed-film processes or biofilm reactors, of which the fluidised-bed reactors are considered to he one of the most effective and promising processes for the treatment of high-strength industrial wastewaters, could he a suitable alternative. The primary aim of this study was to evaluate the suitability of biological fluidised-bed reactors (BFBRs) for the treatment of Fischer-Tropsch reaction water. During this study, the use of aerobic and anaerobic biological fluidised-bed reactors (BFBR), using sand and granular activated carbon (GAC) as support matrices, were evaluated for the treatment of a synthetic effluent analogous to the Fischer-Tropsch reaction water stream. After inoculation, the reactors were operated in batch mode for 10 days at a bed height expansion of 30% and a temperature of 30 ºC to facilitate biofilm formation on the various support matrices. This was followed by continuous operation of the reactors at hydraulic retention times (HRTs) of 2 days. While the COD of the influent and subsequent organic loading rate (OLR) was incrementally increased from 1 600 mg/L to a maximum of 20 000 mg/L and 18 000 mg/L for the aerobic and anaerobic reactors, respectively. Once the maximum influent COD concentration had been achieved the OLR was further increased by decreasing the HRTs of the aerobic and anaerobic reactors to 24h and 8h, and 36h, 24h and 19h, respectively. The dissolved O2 concentration in the main reactor columns of the aerobic reactors was constantly maintained at 0.50 mg/L. Chemical Oxygen Demand (COD) removal efficiencies in excess of 80 % at OLR of up to 30 kg COD/m3.d were achieved in the aerobic BFBRs using both sand and GAC as support matrices. Specific air requirements were calculated to be approximately 35 and 41 m3 air/kg CODrem for the BFBRs using sand and GAC as support matrices, respectively. The oxygen transfer efficiency was calculated to be approximately 5.4 %. At high OLR (> 15 kg COD/m3.d) significant problems were experienced with plugging and subsequent channelling in the BFBR using GAC as support matrix and the reactor had to be backwashed frequently in order to remove excess biomass. Despite these backwash procedures, COD removal efficiencies recovered to previous levels within 24 hours. In contrast, no significant problems were encountered with plug formation and channelling in the BFBR using sand as support matrix. In general the overall reactor performance and COD removal efficiency of the aerobic BFBR using sand as support matrix was more stable and consistent than the BFBR using GAC as support matrix. This BFBR was also more resilient to variations in operational conditions, such as the lowering of the hydraulic retention times and changes in the influent pH. Both aerobic reactors displayed high resilience and COD removal efficiencies in excess of 80 % were achieved during shock loadings. However, both reactors were highly sensitive to changes in pH and any decrease in pH below the pKa values of the volatile fatty acids in the influent (pKa of acetic acid = 4.76) resulted in significant reductions in COD removal efficiencies. Maintenance of reactor pH above 5.0 was thus an essential facet of reactor operation. It has been reported that the VFA/alkalinity ratio can be used to assess the stability of biological reactors. The VFA/alkalinity ratios of the aerobic BFBRs containing sand and GAC as support matrices were stable (VFNalkalinity ratios of < 0.3 - 0.4) until the OLR increased above 10 kg/m3.d. At OLRs higher than 10 kg/m3.d the VFA/alkalinity ratios in the BFBR using sand support matrix increased to 4, above the failure limit value of 0.3 - 0.4. In contrast the VFA/alkalinity ratios of the BFBR using GAC support matrix remained stable until an OLR of 15 kg/m3.d was obtained, where the VFA/alkalinity ratios then increased to > 3. Towards the end of the study when an OLR of approximately 25 kg/m3.d was obtained the VFA/alkalinity ratios of both the BFBRs using sand and GAC as support matrices increased to 9 and 6 respectively, indicating the decrease in reactor stability and acidification of the process. Total solid (TS) and volatile solid (VS) concentrations in the aerobic BFBRs were initially high and decreased over time. While the total suspended solids (TSS) and volatile suspended solids (VSS) concentrations were initially low and increased over time as the OLR was increased, this is thought to be as a result of decreased HRT leading to biomass washout. The anaerobic BFBR using sand as support matrix never stabilised and COD removal efficiency remained very low (< 30 %), possibly due to the high levels of shear forces. Further studies concerning the use of sand as support matrix were subsequently terminated. An average COD removal efficiency of approximately 60 % was achieved in the anaerobic BFBR using GAC as a support matrix at organic loading rates lower than 10 kg COD/m3.d. The removal efficiency gradually decreased to 50 % as organic loading rates were increased to 20 kg COD/m3.d. At OLRs of 20 kg COD/m3.d, the biogas and methane yields of the anaerobic BFBR using GAC as support matrix were determined to be approximately 0.38 m3 biogas/kg CODrem (0.3 m3 biogas/m3reactor vol.d), and 0.20 m3 CH4/kg CODrem (0.23 m3 CH4/m3reactor vol.d), respectively. This value is 57 % of the theoretical maximum methane yield attainable (3.5 m3 CH4/kg CODrem). The methane yield increased as the OLR increased, however, when the OLR reached 8 kg/m3.d the methane yield levelled off and remained constant at approximately 2 m3 CH4/m3reactor vol.d. Although the methane content of the biogas was initially very low (< 30 %), the methane content gradually increased to 60 % at OLRs of 20 kg COD/m3.d. The anaerobic BFBR using GAC as support matrix determined that as the OLR increased (>12 kg/m3.d), the VFA/alkalinity ratio increased to approximately 5, this is indicative of the decrease in stability and acidification of the process. The anaerobic BFBR using GAC as support matrix experienced no problems with plug formation and channelling. This is due to the lower biomass production by anaerobic microorganisms than in the aerobic reactors. The TS and VS concentrations were lower than the aerobic concentrations but followed the same trend of decreasing over time, while the TSS and VSS concentrations increased due to decreased HRTs. The anaerobic BFBR was sensitive to dramatic variations in organic loading rates, pH and COD removal efficiencies decreased significantly after any shock loadings. Compared to the activated sludge systems currently being used for the biological treatment of Fischer-Tropsch reaction water at SASOL SynFuels, Secunda, South Africa, a seven-fold increase in OLR and a 55 % reduction in the specific air requirement was achieved using the aerobic BFBRs. The methane produced could also be used as an alternative source of energy. It is, however, evident that the support matrix has a significant influence on reactor performance. Excellent results were achieved using sand and GAC as support matrices in the aerobic and anaerobic BFBRs, respectively. It is thus recommended that future research be conducted on the optimisation of the use of aerobic and anaerobic BFBRs using these support matrices. Based on the results obtained from this study, it can be concluded that both aerobic and anaerobic treatment of a synthetic effluent analogous to the Fischer-Tropsch reaction water as generated by SASOL in the Fischer-Tropsch Synthol process were successful and that the application of fluidised-bed reactors (attached growth systems) could serve as a feasible alternative technology when compared to the current activated sludge treatment systems (suspended growth) currently used. Keywords: aerobic treatment, anaerobic treatment, biological fluidised-bed reactors, petrochemical effluent, Fischer-Tropsch reaction water, industrial wastewater. / Thesis (M. Omgewingswetenskappe)--North-West University, Potchefstroom Campus, 2004.

The general aim of the study was to determine the effect of employee engagement on performance in a form of quality in the petrochemical industry. This type of study has never been conducted within this particular environment and as such a valuable contribution could be made to more effective performance management within this context. Two questionnaires were administered, namely the Utrecht Work Engagement Scale (UWES) and Total Quality Management. A response rate of 83% was obtained from a sample of 200 employees. The data showed a statistically significant positive relationship between employee engagement and TQM dimensions. The data also showed that there were some significant differences for various demographic groups and their level of engagement. Managers need to enable an organisation to attract, develop and retain highly engaged employees to ensure a sustainable competitive advantage. Limitations within the study were identified and recommendations for future research were made. / Thesis (MBA)--North-West University, Potchefstroom Campus, 2013.