The rollers of run out table in Hot Strip Mill are operated with variable high rotational speed under a severe environment of high temperature and much cooling water around. And the table takes long space about 128 meters of length with over 330 rollers. The rollers of this area often break down, and it takes long to make urgent repair. So it costs about ten million NT dollars per year for mill shut-down. Although some improvements have been made before, the troubles still happens frequently. Then the temporary countermeasures of shortening the maintenance cycle and increasing the grease supply have been applied to prevent the break-down frequency from aggravation . But it wastes the cost and does not meet the environmental policy. This study analyzes many damage phenomena. Then it assumes that the 75% of roller running break-down is bearing damage resulting from bad lubrication condition and abnormal axial load. The cooling water which penetrates into bearing housing will result in grease emulsification and its consistency diluting. This certainly causes the bad lubrication condition and bearing rusting. In the meantime, if the floating function of roller bearing is inactive, the bearings will be operated under abnormal high axial load and without appropriate lubrication. Then the bearing will be damaged rapidly and must be repaired quickly. In order to improve bad lubrication and bearing rusting, this study modifies sealing arrangement and grease feeding circuit for bearing housing with the special functions of water obstruction, drainage and resistance to prevent water penetration. In addition, the overflow of grease will be collected to meet the environmental needs. Meanwhile, to look for better water resistance and mechanical stability for greasing, the study also discusses the relationship between consistency variation and thickening soap base after grease emulsification. During a three-month running of the new design , the water contents are stably under 1.5% which has greatly advanced. And the quantity of grease supply is under 10% of existing one. In order to improve the inactive floating function of roller bearings, this study not only analyzes the derivation of problems but also modifies the dimensional tolerance and adds cylindricity of geometric tolerance for the bore of bearing housing. This will ensure complete loose fit and shape accuracy to prevent the interference fit between the bore and bearing caused by manufacturing inaccuracy or other mistakes

No description available.

To assess polishing of anaerobic secondary effluent and symbiotic bioremediation of primary effluent by microalgae, bench scale bubbling column reactors were operated in batch modes to test nutrients removal capacity and associated factors. Chemical oxygen demand (COD) together with oil and grease in terms of hexane extractable material (HEM) in the reactors were measured after batch cultivation tests of Chlorella Vulgaris, indicating the releasing algal metabolites were oleaginous (dissolved HEM up to 8.470 mg/L) and might hazard effluent quality. Ultrafiltration adopted as solid-liquid separation step was studied via critical flux and liquid chromatography-organic carbon detection (LC-OCD) analysis. Although nutrients removal was dominated by algal assimilation, nitrogen removal (99.6% maximum) was affected by generation time (2.49 days minimum) instead of specific nitrogen removal rate (sN, 20.72% maximum), while phosphorus removal (49.83% maximum) was related to both generation time and specific phosphorus removal rate (sP, 1.50% maximum). COD increase was affected by cell concentration (370.90 mg/L maximum), specific COD change rate (sCOD, 0.87 maximum) and shading effect. sCOD results implied algal metabolic pathway shift under nutrients stress, generally from lipid accumulation to starch accumulation when phosphorus lower than 5 mg/L, while HEM for batches with initial nitrogen of 10 mg/L implied this threshold around 8 mg/L. HEM and COD results implied algal metabolic pathway shift under nutrients stress. Anaerobic membrane bioreactor effluent polishing showed similar results to synthetic anaerobic secondary effluent with slight inhibition while 4 symbiotic bioremediation of raw municipal wastewater with microalgae and activated sludge showed competition for ammonium together with precipitation or microalgal luxury uptake of phosphorus. Critical flux was governed by algal cell concentration for ultrafiltration membrane with pore size of 30 nm, while ultrafiltration membrane rejected most biopolymers (mainly polysaccharides). Further research would focus on balancing cell growth, specific nutrients removal, and specific COD change by utilizing rotating biological contactor.

This diploma thesis is an experimental study of grease lubrication in a starved elastohydrodynamic lubricated (EHL) contact. Lubricating film thickness is measured with tribological experimental device ball-on-disc using optical interferometry and high speed camera. The experiment is aimed at a comparison of results acquired by ball-on-disc device and full scale axial bearing. In addition, this paper also investigates the influence of number of the rolling elements (overrolling time) on the resulting film thickness.

This thesis aims to describe the differences in grease behaviour caused by degradation. Observation of EHL contact and its surroundings is done using optical fluorescence, which allows to measure lubricant thickness even if it is discontinuous and air is present. New grease is observed, along with samples aged in bearings. One sample was worked for 1000 hours, which was the planned duration of the experiment. Two other samples were stopped prematurely after approx. 900 hours. Several possible age-related factors were examined and strong link between contamination and grease behaviour was found. In observed cases, contamination was identified to be the leading cause of lubricant shortage near EHL contact, which is one of possible bearing failure causes. The results expand existing knowledge about grease lubrication topic, but much further research is needed.

Caixas de gordura são dispositivos para retenção de material gorduroso, de origem animal e vegetal, proveniente de pias de cozinha. Sua instalação é exigida por muitos municípios para liberação de ligações de esgoto, visando reduzir as concentrações de óleos e graxas (OG) lançadas no sistema público de coleta e tratamento. Um fator primordial para que estas caixas cumpram suas funções é o estabelecimento de rotinas de manutenção envolvendo inspeção e limpeza periódica. A instalação de locais para recebimento e pré-tratamento dos resíduos retirados das caixas de gordura pode incentivar boas práticas de operação e manutenção destes dispositivos. Diante disso, os objetivos desta pesquisa contemplam a caracterização de resíduos acumulados em caixas de gordura e a avaliação da flotação como alternativa para o seu pré- tratamento, seguido de caracterização do óleo extraído da escuma produzida no flotador. Para tanto, materiais acumulados em caixas de gorduras de fontes distintas foram caracterizados, possibilitando observar grande variação em sua composição, e elevadas concentrações de DBO, DQO, SST e OG. Para verificar o desempenho da flotação visando à redução de OG no efluente pré-tratado, foram realizados ensaios em bancadas e testados quatro produtos químicos coagulantes, sendo eles o PAC, o cloreto férrico, o tanino e o polímero catiônico. Todos apresentaram eficiências elevadas na remoção de OG, porém o produto que apresentou mais vantagens na aplicação foi o polímero. Utilizando o polímero, foram realizados ensaios para verificação do desempenho de várias dosagens associadas a três pH de coagulação diferentes e o melhor desempenho se deu com a aplicação de 30 mg/L de polímero combinada ao pH 4,3, natural da amostra. Foram também realizados ensaios utilizando diferentes relações A/S (7,5/1000, 15/1000 e 22/1000 gar/gsólidos),obtendo-se melhores remoções de OG com a utilização da relação 22/1000 gar/gsólidos. Os materiais flotados obtidos nos ensaios de avaliação da relação A/S foram caracterizados e apresentaram concentrações de ST entre 9,7 e 10,6% e de OG entre 6,1 e 6,7%. Baseado nos resultados obtidos a flotação mostra-se como alternativa com bom desempenho para o pré- tratamento dos resíduos estudados. Para avaliar a dificuldade do manuseio dos resíduos provenientes de caixas de gordura, uma planta piloto foi operada, e entre as principias dificuldades observadas estão o odor intenso, a necessidade de remoção de sólidos grosseiros e de homogeneização do resíduo no tanque de equalização. Visando reaproveitamento do resíduo flotado, foi realizada a extração do óleo com solvente de uma amostra deste material (com teor de sólidos de 8,86%), obtendo a recuperação de 30g óleo/L resíduo com acidez de 13,76 mg KOH/L. A elevada acidez indica a necessidade de purificação, se o objetivo for a produção de biodiesel. / Grease traps are devices that retain animal and vegetal fatty material from kitchen sinks. Many municipalities demand its installation in order to connect house wastewater to the public network, aiming to reduce fat, oil and grease concentration in the collecting and treatment systems. The establishment of maintenance schedule involving inspection and periodic cleaning is a key factor to the right functioning of the device. The existence of appropriated sites to receive and pretreat grease trap wastes may stimulate good practices on maintenance and operation of these devices. In this direction, the objectives of this research are the characterization of grease trap wastes and the evaluation of flotation as an alternative for its pretreatment, followed by characterization of the oil extracted from the scum formed at flotator. Therefore, grease trap wastes from different sources were collected and characterized. It could be observed a wide variation on its composition and high concentrations of BOD, COD, TSS and FOG. Lab scale tests were performed to assess flotation performance to reduce pretreated effluent FOG using four chemical coagulants: PAC, ferric chloride, tannin and cationic polymer. All of them achieved high efficiency on FOG removal, however the product that presented more advantages on application was polymer. More tests were performed using several dosages of polymer associated to three pH coagulation conditions. The combination that resulted in the best efficiency was 30 mg/L of polymer combined to pH 4.3, samples natural pH. Different A/S ratios were also tested (7.5/1000, 15/1000, 22/1000 gair/gsolids), the ratio 22/1000 gair/gsolids presented the best FOG removal efficiencies. Floated material from A/S ratio tests were characterized and presented TS concentrations between 9.7% and 10.6% and FOG was from 6.1% to 6.7%. Based on the obtained results, flotation appears as a high performance alternative for the pretreatment of studied wastes. A pilot plant was operated to evaluate problems related to grease trap waste handling. The main problems were: bad odor, the need of screening and waste homogenization in equalization tank. Aiming to reuse the floated waste, oil was extracted from a sample (8.86% solid content) using solvent, achieving the recovery of 30g oil/L waste with 13.76 mgKOH/L acidity. The high acidity points to the need of purification if biodiesel production is intended.

Caixas de gordura são dispositivos para retenção de material gorduroso, de origem animal e vegetal, proveniente de pias de cozinha. Sua instalação é exigida por muitos municípios para liberação de ligações de esgoto, visando reduzir as concentrações de óleos e graxas (OG) lançadas no sistema público de coleta e tratamento. Um fator primordial para que estas caixas cumpram suas funções é o estabelecimento de rotinas de manutenção envolvendo inspeção e limpeza periódica. A instalação de locais para recebimento e pré-tratamento dos resíduos retirados das caixas de gordura pode incentivar boas práticas de operação e manutenção destes dispositivos. Diante disso, os objetivos desta pesquisa contemplam a caracterização de resíduos acumulados em caixas de gordura e a avaliação da flotação como alternativa para o seu pré- tratamento, seguido de caracterização do óleo extraído da escuma produzida no flotador. Para tanto, materiais acumulados em caixas de gorduras de fontes distintas foram caracterizados, possibilitando observar grande variação em sua composição, e elevadas concentrações de DBO, DQO, SST e OG. Para verificar o desempenho da flotação visando à redução de OG no efluente pré-tratado, foram realizados ensaios em bancadas e testados quatro produtos químicos coagulantes, sendo eles o PAC, o cloreto férrico, o tanino e o polímero catiônico. Todos apresentaram eficiências elevadas na remoção de OG, porém o produto que apresentou mais vantagens na aplicação foi o polímero. Utilizando o polímero, foram realizados ensaios para verificação do desempenho de várias dosagens associadas a três pH de coagulação diferentes e o melhor desempenho se deu com a aplicação de 30 mg/L de polímero combinada ao pH 4,3, natural da amostra. Foram também realizados ensaios utilizando diferentes relações A/S (7,5/1000, 15/1000 e 22/1000 gar/gsólidos),obtendo-se melhores remoções de OG com a utilização da relação 22/1000 gar/gsólidos. Os materiais flotados obtidos nos ensaios de avaliação da relação A/S foram caracterizados e apresentaram concentrações de ST entre 9,7 e 10,6% e de OG entre 6,1 e 6,7%. Baseado nos resultados obtidos a flotação mostra-se como alternativa com bom desempenho para o pré- tratamento dos resíduos estudados. Para avaliar a dificuldade do manuseio dos resíduos provenientes de caixas de gordura, uma planta piloto foi operada, e entre as principias dificuldades observadas estão o odor intenso, a necessidade de remoção de sólidos grosseiros e de homogeneização do resíduo no tanque de equalização. Visando reaproveitamento do resíduo flotado, foi realizada a extração do óleo com solvente de uma amostra deste material (com teor de sólidos de 8,86%), obtendo a recuperação de 30g óleo/L resíduo com acidez de 13,76 mg KOH/L. A elevada acidez indica a necessidade de purificação, se o objetivo for a produção de biodiesel. / Grease traps are devices that retain animal and vegetal fatty material from kitchen sinks. Many municipalities demand its installation in order to connect house wastewater to the public network, aiming to reduce fat, oil and grease concentration in the collecting and treatment systems. The establishment of maintenance schedule involving inspection and periodic cleaning is a key factor to the right functioning of the device. The existence of appropriated sites to receive and pretreat grease trap wastes may stimulate good practices on maintenance and operation of these devices. In this direction, the objectives of this research are the characterization of grease trap wastes and the evaluation of flotation as an alternative for its pretreatment, followed by characterization of the oil extracted from the scum formed at flotator. Therefore, grease trap wastes from different sources were collected and characterized. It could be observed a wide variation on its composition and high concentrations of BOD, COD, TSS and FOG. Lab scale tests were performed to assess flotation performance to reduce pretreated effluent FOG using four chemical coagulants: PAC, ferric chloride, tannin and cationic polymer. All of them achieved high efficiency on FOG removal, however the product that presented more advantages on application was polymer. More tests were performed using several dosages of polymer associated to three pH coagulation conditions. The combination that resulted in the best efficiency was 30 mg/L of polymer combined to pH 4.3, samples natural pH. Different A/S ratios were also tested (7.5/1000, 15/1000, 22/1000 gair/gsolids), the ratio 22/1000 gair/gsolids presented the best FOG removal efficiencies. Floated material from A/S ratio tests were characterized and presented TS concentrations between 9.7% and 10.6% and FOG was from 6.1% to 6.7%. Based on the obtained results, flotation appears as a high performance alternative for the pretreatment of studied wastes. A pilot plant was operated to evaluate problems related to grease trap waste handling. The main problems were: bad odor, the need of screening and waste homogenization in equalization tank. Aiming to reuse the floated waste, oil was extracted from a sample (8.86% solid content) using solvent, achieving the recovery of 30g oil/L waste with 13.76 mgKOH/L acidity. The high acidity points to the need of purification if biodiesel production is intended.

Research and experience has shown that vegetable oil can be processed, by transesterification, into a useable fuel for compression ignition engines. Earlier research examined using straight vegetable oil as a fuel, but found it to cause detrimental engine problems. Trial and error has shown that heating the vegetable oil prior to injection, is a viable option. A diesel vehicle engine was operated for over 188 hours or approximately 7,000 miles, using waste cooking oil as fuel. The longevity of the vehicle engine was limited by an undetermined engine failure. Using stationary testing, with no engine load and various power settings, engine emissions of several engines operating on waste cooking oil were compared to emissions from two other fuels, diesel and Biodiesel, and found to be very positive. Waste vegetable oil (WVO) had lower overall emissions than diesel and lower levels of nitrogen species than Biodiesel. Agricultural yield predictions estimate that currently only 5% and at most 20% of all diesel fuel needs can be met with vegetable oil. Currently WVO is a disposal problem. It is primarily used as a feedstock. WVO is not a commodity and has disposal fees associated with it. If WVO is used as a fuel, it would not only provide another source for disposal, but it may also increase the value of WVO making it a commodity instead of a disposal burden.

A clutch actuator is used in a vehicle to transmit movement and force from the clutch pedal to the release bearing of the clutch. A pneumatic clutch actuator consists of an anodised aluminium cylinder, inside of which a piston, with a rubber lip seal and a PTFE guiding ring, slides. The system is lubricated with silicone grease before assembly. A commercial clutch actuator of this type, has a service life of 3 million actuations and must function in a wide temperature range, from -40 ºC to 140 ºC. In this thesis, the complex tribological system of pneumatic clutch actuators has been studied. Field worn actuators have been disassembled and investigated. A laboratory test method has been developed to understand the tribomechanisms present in pneumatic clutch actuators. The test method's capability of simulating the real contact has been verified, by the comparison with studied actuators from the field. The influence of contact parameters: temperature, load, lubrication and particle contamination, has been investigated. In addition, different anodised aluminium surfaces have been studied. The manufacturing method of the aluminium cylinder influences surface topography and structure of the oxide, resulting in different mechanical and frictional properties. The wear during tests with only silicone grease is reminiscent, but on a lower scale, to the wear during tests with a mixture of silicone grease and standard dust. The initially applied amount of silicone grease is not important, the friction seems to depend on the amount of silicone grease that is dragged into or pushed out from the contact area during testing. Silicone grease lubrication reduces wear of the lip seal. However, during some tests, an adhesive layer, composed of  grease residuals and some PTFE, was formed on the lip. A triple PTFE transfer, from guiding ring to aluminium surface, to lip seal, to aluminium surface, occurred. Such transfer of material from the PTFE guiding ring was detected from the unlubricated tests, and also from the silicone grease lubricated tests, i.e. silicone grease lubrication does not prevent PTFE material transfer.

Energy and vegetable oil prices have caused many biodiesel producers to turn to waste cooking oils as feedstocks. These oils contain high levels of free fatty acids (FFAs) which make them difficult or impossible to convert to biodiesel by conventional production methods. Esterification is required for ultra-high FFA feedstocks such as Brown Grease. In addition, ultrasonic irradiation has the potential to improve the kinetics of the esterification reaction. 2-level, multi-factor DOE experiments were conducted to characterize the esterification reaction in ultra-high FFA oils as well as determine whether ultrasonic irradiation gives any benefit besides energy input. The study determined that sulfuric acid content had the greatest effect followed by temperature and water content (inhibited reaction). Methanol content had no effect in the range studied. A small interaction term existed between sulfuric acid and temperature. The study also concluded that sonication did not give any additional benefit over energy input.