In the current era, oil deficit countries around the world seriously consider shifting dependence from conventional gasoline to renewable bio-ethanol fuel in the transport industry. Arguably, blending l0vol% dry ethanol with 90vol% unleaded gasoline enables ethanol fuel to penetrate the fuel market at relatively lower development costs. Despite creating an important market for the ethanol industry, fuels containing dry ethanol of differential proportions multiply the local risks associated with fuel combustion. Making a sale of one drop of ethanol fuel, for example, is intrinsically tied to the sale of more drops of imported gasoline. Furthermore, an increase (decrease) in conventional fuel prices directly influences a decline (increase) in daily sales of ethanol fuel. Blending bio-ethanol fuel with conventional gasoline in various proportions fails to address the multifaceted fossil fuel crisis in oil deficit countries. Although reducing bio-ethanol production costs can buffer fuel prices to a significant degree when blended in higher ratios, industrial competition for bio-feedstock is a serious limitation for bio-ethanol development in all parts of the globe. Nevertheless, advances in biotechnology may allow the use of a wide range of cheaper ethanol feedstocks (e.g. lignocellulose) leading to an important reduction in ethanol production costs. Temporal and spatial variability of lignocellulosic ethanol potentials in the sugar industry is investigated over southern Africa as a whole. The influence of extremely low (high) production of sugar cane on the potentials development of lignocellulosic ethanol plants is demonstrated in this work. Characterization of bioethanol fuel markets on the basis of blending with gasoline is undertaken at the subcontinental scale. The connectivity between development, consumption per capita, population growth, bio-ethanol energy demand, as well as the critical limits of land stock potentials is examined in this study. On the basis of the special influence that each of the processes indicated above have on bio-ethanol fuel development, an integrated approach toward optimizing the total value of bio-ethanol fuel in the region is formulated. This approach allows the investigation to determine whether critical and beyond critical conditions of land stock lead to a collapse of a human consumption type or whether bio-ethanol fuel development is a totally viable process. Finally, this work ascertains whether sustainable biofuel development is an oxymoron because human development demands a constantly growing fuel consumption per capita, or because of increasing the lower limit, with an infinite upper limit for human development, or as a product of the combined effects of increasing human population with a higher consumption rate per capita of non-growing and non-developing land stock units. / Thesis (Ph.D.)-University of KwaZulu Natal, Durban, 2004.

The South African sugar industry generates excessive amounts of sugar cane bagasse (~ 25 wt% of feed) as a byproduct during the extraction of sugar juice from cane. Although bagasse is extensively consumed in various processes, a substantial amount remains unexploited. The industry's core business is the production of refined sugar which involves among others, a step of decolourising raw sugar liquor. Activated carbons are well known adsorbents and their excellent decolourisation capabilities have been established since 1800 in the sugar industry. The possibility of making suitable in-house activated carbons from sugar cane bagasse to aid the decolourisation process of raw sugar liquor is of interest to the growing South African sugar industry. The purposes of this research study were to develop an understanding on the manufacture of activated carbons from sugar cane bagasse, produce suitable activated carbons on a laboratory scale, characterize them and subsequently determine their sugar decolourisation capabilities under simulated conditions. The application of the two-step physical method of processing was found to be the most effective and feasible route to produce activated carbons from sugar cane bagasse for the purposes of decolorizing unrefined sugar. A semi-batch process was developed whereby compressed sugar cane bagasse was pyrolysed under a nitrogen atmosphere at a heating rate of 10 °C/min to the final pyrolysis temperature for a desired hold time resulting in bagasse chars with a rudimentary pore structure. These bagasse chars were subsequently subjected to partial and controlled gasification with a steam/nitrogen mixture at higher temperatures to produce the final activated carbon product. Both pyrolysis and activation were carried out in a pyrolysis furnace that was modified to represent a fixed bed reactor system. The process was designed such that it included a steam supply and a gas cleaning system. Feasible processing conditions were established by varymg the temperature, hold time and partial pressure of steam in the pyrolysis furnace. The bagasse chars and final activated carbons were characterized with respect to surface area, pore volume, pore size distribution, methylene blue number, iodine number and molasses number. The optimum pyrolysis conditions were found to be at heating rate of 10°C/min to the final pyrolysis temperature of 680 °C for a hold time of 1 hour, which gave rise to microporous carbons. Increasing the steam partial pressure and activation temperature during activation of bagasse chars resulted in the gasification reaction proceeding at a much faster rate leading to well developed mesoporous activated carbons having high adsorption capacity for large colour bodies present in molasses and sugar liquor. This was achieved by activating bagasse chars at a temperature of 900°C for 2 hours with a steam / nitrogen mixture of 1:0.6 which resulted in 50% bum-off being reached. Excellent powder and granular activated carbons were produced from sugar cane bagasse fibres by the established process with the latter being mixed with refined sugar prior to pyrolysis and activating for half an hour extra. A typical final activated carbon produced in this research possessed a BET surface area of 995 m2/g, pore volume of 0.82 crrr'zg, iodine number of 994 mg/g, molasses number of 700 and methylene blue number of 256 mg/g. High ash content in the bagasse raw material tends to decrease the surface area and pore volume for adsorption of the final activated carbon. Both granular and low ash bagasse activated carbons possess high adsorption capacity to remove large colour bodies from molasses and brown liquor solutions and compare well with commercial Norit N2 carbon . Approximately 80% colour removal was achieved using 0.5 g carboni 100g brown liquor. The bagasse activated carbons were stable in acidic and basic brown liquor solution and maintained their high decolourisation potential. The ability of bagasse activated to replace commercial activated carbons has been proven in this study. The option of producing both granular and powder activated carbons provide flexibility of the sugar industry to choose between batch and continuous adsorption systems during sugar decolourisation. This research has established that the fact that excellent sugar decolourising activated carbons can be produced from South African sugar cane bagasse fibres. However, more research needs to be carried out in order for the sugar industry to take this project to the commercial stage and it is suggested that a pilot study and an economic study be carried out. / Thesis (M.Sc.)-University of Natal, Durban, 2003.

The purpose of clarification in the sugar industry is to remove soluble, insoluble and colloidal matter from cane juice. Efficient clarification is required to produce high quality sugar and to prevent entrainment of solids in downstream equipment. The objective of this study is to produce a Computational Fluid Dynamics (CFD) model of the Magra Ultrasep clarifier. This was accomplished by: • Modelling the hydrodynamics of a laboratory scale clarifier In the Fluent CFD program. • Incorporating the flocculation process into the CFD model. • Performing experiments on a pilot scale clarifier to obtain parameter values for the flocculation model. The hydrodynamic model of the clarifier showed the presence of a recirculation zone above the baffle plate. Particle injections using Fluent's discrete phase modelling option determined that particles within the size range of IOOj..Lm to 4mm would circulate in this region, forming the bed of floc particles required for the Magra Ultrasep to work efficiently. The flocculation process in Fluent was represented using three different solid phases of different particle sizes. Small and medium sized particles were allowed to combine to form larger particles by changing the volume fractions according to three rate equations. A fibre glass laboratory scale model was set up at Maidstone Sugar Mill and fed the same sugar cane juice that enters the Rapi-Dorr clarifiers. The experimental results were then fed into a simplified flocculation model in MATLAB. An overall rate constant (k) of 5kg.m-3.s-) for the flocculation kinetic equation satisfied the experimental result. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2008.

This dissertation focuses on the application of tomography in the sugar milling process, specifically within the vacuum pan. The research aims to improve the efficiency and throughput of a sugar mill by producing real-time images of the boiling dynamic in the pan and hence can be used as a diagnostic tool. The real-time tomography system is a combination of ruggedized data collecting hardware, a switching circuit and software algorithms. The system described in this dissertation uses 16 electrodes and estimates images based on the distinct differences in conductivities to be found in the vacuum pan, i.e. a conductive syrup-like fluid (massecuite) and bubbles. There is a direct correlation between the bubbles produced during the boiling process and heat transfer in the pan. From this correlation one can determine how well the pan is operating. The system has been developed in order to monitor specific parts of a pan for optimal boiling. A binary reconstructed image identifies either massecuite or water vapour. Each image is reconstructed using a modified neighbourhood data collection method and a back projection algorithm. The data collection and image reconstruction take place simultaneously, making it possible to generate images in real-time. Each image frame is reconstructed at approximately 1.1 frames per second. Most of the system was developed in LabVIEW, with some added external drive electronics, and functions seamlessly. The tomography system is LAN enabled hence measurements are initiated through a remote PC on the same network and the reconstructed images are streamed to the user. The laboratory results demonstrate that it is possible to generate tomographic images from bubbles vs massecuite, tap water and deionized water in real-time. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.

The addressed topic is to investigate the power distribution at a base metal refinery and to identify the potential improvement in power consumption efficiency. The work included in this study revealed that the power consumption efficiency at the evaluated base metal refinery can be improved. The significance of this study relates to Eskom’s tariff increases and directive to mining and large industrial companies to reduce their power consumption as well as the recent incremental increase in power tariffs. Base metal refineries are substantial power consumers and will be required to evaluate the efficiency of their base metal production. A load study was conducted at a base metal refinery in order to determine the current power consumption at the various process areas. The measurements obtained from the load study formed the basis for calculations to determine the potential efficiency improvement. The load study revealed that the electro-winning area contributes to the majority of the power consumed (52% of total apparent power) at the refinery. The potential improvement in efficiency at the electro-winning process area was identified by means of evaluating the rectifier and rectifier transformer power consumption. Methods and technologies for the reduction in power consumption was consequently evaluated and quantified. The potential reduction in conductor losses by converting from global power factor correction to localised power factor correction for the major plant areas was furthermore identified as an area of potential efficiency improvement and consequently evaluated. The improvement in motor efficiency across the base metal refinery was identified by means of comparing the efficiency and power factor of high efficiency motors to that of the standard efficiency motors installed at the refinery. The work included in this study reveals that an improvement in power consumption efficiency is achievable at the evaluated base metal refinery. An efficiency improvement of 1.785% (real power reduction of 2.07%) can be achieved by implementing localised power factor correction and high efficiency motors. An average efficiency improvement of 1.282% (total real power reduction of 2.78%) can be achieved with the additional implementation of specialised, high efficiency rectifier transformer designs. The implementation of localised power factor correction as well as high efficiency motors was identified as short term efficiency improvement projects. A financial study was conducted in order to determine the cost and payback period associated with the reduction in real power consumption for implementation of the recommended efficiency improvement projects. The payback period, required to achieve an average efficiency improvement of 1.785%, was calculated to be approximately 4 years. The initial capital investment required to implement the efficiency improvement projects is about R22.5 million. The monthly electricity utility bill savings associated with the efficiency improvement projects is approximately R455,000. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.

Sinapic acid derivatives and tocopherols in refining byproducts of commercially produced expeller-pressed canola oils were characterized and isolated. Additionally, the antioxidant activities of the phenolics were examined by three systems including an in vitro non-biological related assay, a cellular assay and a deep-fat frying model. Sinapic acid (SA： 42.9 µg/g), Sinapine (SP: 199 µg/g), and Canolol (CAN: 344 µg/g) were found in different byproducts of canola oil refining, namely, soapstock, spent bleaching clay, and wash-water, respectively. Tocopherols (3.75 mg/g) and other non-identified phenolic compounds (2.7 mg /g) were found in deodistillates (DDL). CAN and DDL revealed significant protection effect (p<0.05) against hydrogen peroxide induced oxidation in two mammalian cell lines. The results of deep-fat frying studies indicated positive effects of CAN and DDL in preventing lipid oxidation. The canola oils fortified with DDL and CAN showed a considerable reduction (p < 0.05) in oxidation products of lipid after frying.

A piezo-ceramic sensor was developed to measure normal and tangential shear forces applied to a bar at one location in the refining zone of a Sunds Defibrator Conflo® JC-00 refiner. Testing was completed at the Pulp and Paper Research Institute of Canada in Vancouver. BC using CTMP pulp with a stock consistency of 3.15%. Distributions have been determined for peak normal and shear forces. peak coefficient of friction. shear work. and shear lead. These distributions were analysed to assess possible correlations with specific edge load. Force magnitudes were found to increase with an increase in specific edge load. The peak coefficient of friction was calculated that ranged from 0.13 to 0.16. Both the normal and shear force magnitudes varied by as much as a factor of 3, due to rotor out-of-tram of only 0.06 mm. These distributions could provide greater insight to the mechanisms responsible for fibre development in papermaking and thus "In Process" control of various refiner conditions.

京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第24000号 / エネ博第436号 / 新制||エネ||82(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)教授 野平 俊之, 教授 萩原 理加, 教授 佐川 尚 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

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