Dissertations / Theses on the topic 'Coke-oven'

Thesis (MTech(Environmental Health)--Cape Peninsula University of Technology, 2011
Coke ovens may occur in the aluminium, steel, graphite, electrical, and construction industries. In the work area coke-oven workers may be exposed to various chemical compounds. Polycyclic aromatic hydrocarbons (PAHs), as human carcinogen, are primary compounds in coke oven emissions (COEs) generated in the coking process. Coke oven workers are often exposed to PAHs and can lead to a variety of human diseases.The primary routes of potential human exposure to coke oven emissions are inhalation and dermal contact. Occupational exposure may occur during the production of coke from coal, or while using coke to extract metals from their ores to synthesize calcium carbide, or to manufacture graphite and electrodes. Workers at coking plants and coal tar production plants, as well as the residents surrounding these plants, have a high risk of possible exposure to coke oven emissions.It is known that coke production could be carcinogenic to humans (Group-1) by IARC. There has been sufficient epidemiological evidence suggesting an etiological link between carcinogenic polycyclic aromatic hydrocarbon (PAHs) exposure and lung cancer risk among coke-oven workers. Lung cancer among coke-oven workers has been classified as one of the eight prescribed occupational cancers in China, and its incidence rate was about 10 times that of the general population. Therefore, lung cancer of coke-oven workers is still a critical issue in the field of prevention and control of occupational cancers in China.This thesis explores the various exposure levels of workers to PAHs at a steel plant in China. The measurement will focus on the exposure difference of personal sampling among workers in selected job classifications given the job descriptions and the coking process. The Benxi Steel Industry in Liaoning province of China (BXSI) was selected as the research location. Liaoning province is in the North of China and the location of various heavy industries in China. The measurements will be done two separate coke ovens in Benxi Steel Industry. One new coke oven was built in the 90's last century (coke oven N) and the other older coke oven was built in the 1940's in last century (coke oven O). In this research, the total number of employees that were selected in the sample for both coke ovens are 64 samples included 54 coke oven exposure workers and 10 non-exposure administrative workers working at the plants.

La pyrolyse de grains de charbon en four tournant permet de produire un coke réactif principalement utilisé en électrométallurgie. Le but de cette étude est d'analyser et de modéliser les différents phénomènes impliqués dans ce procédé afin d'améliorer le fonctionnement et la conduite de l'installation industrielle. La pyrolyse du charbon a été étudiée par thermogravimétrie et analysé chromatographique des gaz émis afin de déterminer la cinétique de dégagement de chaque constituant des matières volatiles. L’enthalpie de réaction de la pyrolyse a été mesurée par calorimétrie à flux différentiel. Le mouvement de la charge en four tournant a été étudié grâce à des expérimentations en four pilote. Les mesures effectuées concernent le temps de séjour moyen, la distribution des temps de séjour, le profil de chargement et le temps moyen passe par un grain en surface du talus. Des corrélations adaptées à la modélisation du mouvement de la charge ont été déterminées. Les transferts de chaleur ont fait l'objet d'une étude approfondie: ils incluent le transfert en régime transitoire à travers la paroi et le rayonnement paroi/solide qui est partiellement absorbé par le gaz qui s'interpose. La démarche adoptée pour la modélisation de ce procédé a consisté à simuler, dans un premier temps, la pyrolyse d'une particule isolée. Le modèle de grain ainsi établi a ensuite été inséré dans une représentation globale du four en tenant compte de l'hydrodynamique du réacteur, des transferts de chaleur entre la paroi, le solide et le gaz et des réactions de combustion des matières volatiles. Ce modèle a été validé grâce à un ensemble de mesures effectuées sur le four tournant industriel et utilisé avec succès pour l'amélioration du fonctionnement de cette installation

A presente pesquisa objetivou estudar a remoção dos poluentes presentes em uma água residuária de coqueria, através do processo biológico de nitritação/desnitritação operando um reator de lodo ativado em bateladas seqüenciais em duas etapas sucessivas. Durante a primeira, o reator foi alimentado com um efluente sintético composto por dois poluentes abundantes em despejos de coqueria: nitrogênio amoniacal (500 mg N/L) e fenol (1.000 mg C6H5OH/L). Na segunda, o reator foi alimentado com o despejo gerado na unidade de coqueria de uma indústria siderúrgica integrada. Ao longo da primeira etapa, ao final da fase aeróbia dos 28 ciclos de tratamento, foi possível alcançar eficiências de remoção de N-NH3 superiores a 90% com predominância do N-NO2 - na massa líquida do reator evidenciado pelas relações N-NO2 -/ (N-NO2 - + N-NO3 -) superiores a 86%. O principal mecanismo de inibição das bactérias oxidantes de nitrito (BON) foram concentrações de amônia livre no conteúdo do reator entre 3,2 e 19,5 mg NH3/L. As taxas específicas de nitritação variaram entre 0,03 e 0,11 kg N-NH3/ kg SSV.dia, para temperaturas no conteúdo do reator entre 15 e 34°C. Durante a fase anóxica, o fenol mostrou-se adequado como fonte de carbono para a biomassa desnitritante, desde que as taxas de aplicação volumétricas fossem inferiores a 0,02 kg fenol/m³.hora. Respeitando essa condição, foi possível alcançar: eficiências de remoção de fenol entre 45 e 56%; taxas específicas de remoção de fenol entre 0,03 e 0,09 kg C6H5OH / kg SSV.dia; taxas específicas de desnitritação entre 0,03 e 0,06 kg N-NO2 -/ kg SSV.dia e eficiências de remoção de (N-NO2 - + N-NO3 -) superiores a 95%. Ao longo da fase anóxica foram retiradas amostras do conteúdo do reator para a realização de análises de nitrofenóis (NF). Os resultados acusaram a presença de 2 nitrofenol e 4 nitrofenol em concentrações proporcionais à taxa de aplicação volumétrica do fenol na massa líquida do reator. A presença desses compostos em concentrações inferiores a 0,5 mg/L não causou impacto sobre a desnitritação biológica. As análises realizadas em amostras coletadas ao final da reação anóxica, não acusaram a presença de 2 e 4 NF, demonstrando que esses compostos podem ser biodegradados por uma biomassa bem adaptada ao fenol. A concepção do sistema para tratamento da água residuária de coqueria via nitritação/desnitritação envolveu a operação de dois reatores (principal e reator de polimento) operados em bateladas seqüenciais. As condições de operação do reator principal eram manipuladas para viabilizar o acúmulo de NNO2 - ao final da fase aeróbia e promover a desnitritação durante a fase anóxica, utilizando como fonte de carbono a própria matéria orgânica presente no despejo. Como o sobrenadante do reator principal apresentava concentrações elevadas de N-NO2 -, esse efluente era aplicado no reator de polimento, juntamente com etanol como fonte de carbono para redução do NNO2 -. Ao final da fase aeróbia dos ciclos de tratamento conduzidos no reator principal alcançaram-se: relações NO2 -/ (N-NO2 - + N-NO3 -) superiores a 88%; eficiências de remoções de nitrogênio total superiores a 60%; remoções de N-NH3 superiores a 90%, para valores de pH na massa líquida do reator entre 7,8 e 8,5 e, temperatura entre 23 e 31°C. Tal qual ocorrido durante a primeira etapa da investigação, o principal mecanismo de inibição da atividade das bactérias oxidantes de nitrito foi a toxicidade conferida pelas concentrações de amônia livre (3,7 a 15,7 mg NH3/L) no conteúdo do reator. Durante a fase anóxica, as eficiências de remoção de (N-NO2 - foram limitadas pela disponibilidade de matéria orgânica biodegradável no despejo da coqueria, razões DBO/DQOafluente superiores a 80% resultaram em remoções de N-NO2 - próximas de 100%. Quanto ao reator de polimento, pode-se afirmar que o etanol teve um efeito positivo sobre a remoção de matéria orgânica da água residuária da coqueria, considerando a configuração (dois lodos) utilizada.
The present research aimed to study the coke-oven wastewater treatment over nitritation/denitritation in an activated sludge sequencing batch reactor in two successive phases. During the first one, the reactor was fed with a synthetic effluent composed by two abundant pollutants present in coke-oven wastewaters: total ammonia nitrogen (500 mg TAN.l-1) and phenol (1,000 mg C6H5OH.l-1). During the second phase, the reactor was fed with the wastewater produced in an integrated steel industrys coke-plant. The results of the first phase (28 cycles) showed that was possible to achieve TAN removal efficiencies higher than 90% with NO2 --N predominance in the reactor content, evidenced by the rates NO2 --N/ (NO2 --N + NO3 --N) higher than 86%. The main mechanism of the nitrite oxidizer bacteria (NOB) inhibition was free ammonia concentrations between 3.2 and 19.5 mg NH3.l-1. The specific nitritation rates varied between 0.03 and 0.11 kg TAN. kg VSS-1.d-1, for temperatures between 15 and 34oC. Phenol showed to be suitable as carbon source for denitrifying biomass, once the volumetric application rates were lower than 0.02 kg phenol.m-3.h-1. Obeying this condition, it was possible to achieve: phenol removal efficiencies between 45 and 56%; specific phenol removal rates between 0.03 and 0.09 kg C6H5OH. kg VSS-1.d-1; specific denitritation rates between 0.03 and 0.06 kg NO2 --N . kg VSS-1.d-1 and removal efficiencies of (NO2 --N + NO3 --N) higher than 95%. During the anoxic phase, samples were collected from the reactor content for nitrophenols analyses. The results showed the presence of 2- nitrophenol (2-NP) and 4-nitrophenol (4-NP) in concentrations proportional to phenol volumetric application rate in the reactor liquid mass. The presence of those compounds in concentrations lower than 0.5 mg/L does not cause impact over the biological denitritation. The analyses accomplished in samples collected at the end of the anoxic reaction do not show the presence of 2 and 4-NP, demonstrating that these compounds can be biodegraded by a well-adapted biomass. The arrangement of the system for the treatment of coke-oven wastewater (Phase 02) over nitritation/denitritation involved the operation of two sequencing batch reactors (the main reactor and the polishing one). The operational conditions of the main reactor were manipulated to make feasible the NO2 --N accumulation at the end of the aerobic stage and promote the denitritation using the own organic matter present in the cokeoven wastewater as carbon source. As the supernatant of the main reactor presented high nitrite concentrations, this effluent was conducted to a biological denitrifying polishing reactor with ethanol as carbon source. At the end of the aerobic stage of the treatment cycles conducted in the main reactor, it was achieved: NO2 --N/ (NO2 --N + NO3 --N) higher than 88%; total nitrogen removal efficiencies higher than 60%; ammonia nitrogen removal higher than 90%. As occurred during the first phase of the investigation, the main NOB activity inhibition was the toxicity of the free ammonia concentrations (3.7 to 15.7 mg NH3.l-1) in the reactor content. At the end of anoxic stage, the NO2 --N removal efficiencies were limited by the availability of the biodegradable organic matter in the coke-oven wastewater but BOD/CODinfluent higher than 80% resulted in NO2 --N removals next to 100%. Regarding to the polishing reactor, it can be stated that the ethanol had a positive effect over the organic matter removal of the coke-oven wastewater.

A reutilização de resíduos e sua destinação são desafios seguidamente enfrentados na indústria. Por ser extensa e empregar uma grande variedade de processos, matérias-primas e insumos, a cadeia do aço se beneficia por ter ampla flexibilidade e diversas possibilidades de reintrodução de compostos em sua rota de fabricação. Resíduos carbonosos, por exemplo, podem ser parcialmente usados em misturas de carvões no processo de coqueificação dependendo do tamanho e da composição química. Este trabalho, teve como objetivo, avaliar a influência da adição de moinha de carvão vegetal em uma mistura de carvões para a produção de coques em forno piloto de coqueificação e determinar os teores máximos de incorporação suportados pela mistura, avaliando parâmetros de qualidade do coque. Para isso, a moinha de carvão vegetal de eucalipto foi introduzida em duas frações granulométricas distintas, uma composta por partículas mais grosseiras (fração G) e outra composta por partículas mais finas (fração F), e caracterizado juntamente com a mistura utilizada. Posteriormente, os coques produzidos em forno piloto também foram caracterizados através de diversas análises: imediata, elementar, área superficial, porosidade, textura óptica, reatividade em termobalança, CRI/CSR e DI150/15. Os resultados atingidos mostraram que inserção da fração G de moinha comprometeu menos os parâmetros de qualidade dos coques com carvão vegetal. Teores de até 3% de moinha foram suportados para essa distribuição de tamanho de partícula enquanto que para a fração F, somente 1%. Outro fator observado foi que os coques produzidos com adição de moinha de carvão vegetal não tiveram queda significativa no teor de enxofre, a exceção da amostra contendo 10% de carvão vegetal na fração G. Em todas as amostras com moinha de carvão vegetal também foi possível notar o aumento da área superficial em relação ao coque de referência. Os testes termogravimétricos dinâmicos também trouxeram informações relevantes a respeito das temperaturas e taxas aparentes de reações dos coques feitos com moinha de carvão vegetal.
The reuse of waste materials and its destination are challenges continuously faced for industry. For being far-flung and apply a huge variety of process, raw materials and inputs, the steel supply chain benefits from having a high flexibility and many possibilities of reintroducing compounds in its manufacturing route. For example, carbonaceous materials can be used partially in coal blends for cokemaking process depending on particle size and chemical composition. The current work aimed to evaluate the influence of adding fine charcoal to a coal blend for coke production in a pilot oven and to determine the maximum content tolerated for the blend, assessing coke quality parameters. For this, a eucalyptus charcoal residue was introduced in two different size distributions, one composed of coarser particles (fraction G) and another of finer (fraction F), and characterized together with the coal blend used. Afterwards, the cokes produced in pilot oven were also characterized through several analyzes: proximate, ultimate, surface area, porosity, optical texture, reactivity on thermobalance, CRI/CSR e DI150/15. The results achieved showed that the insertion of charcoal on fraction G compromised less the quality parameters of cokes with charcoal. Contents up to 3% of charcoal were tolerated for this particle size distribution while for fraction F, only 1%. Another point noticed was that the coke produced with charcoal addition had no significant drop on sulfur content, with the exception of the coke sample with 10% of charcoal and fraction G. In all samples with charcoal it was also possible to see an increase on surface area in relation to the reference coke. The dynamic thermogravimetric tests also provided relevant information regarding to the temperatures and apparent reaction rates of cokes made with charcoal.

The topic of this diploma thesis is to design the co-firing of blast furnace gas and coke-oven gas. First, the stoichiometric calculation for the gas mixture was made. It is followed with the determination of basic measures of heating surfaces and with their thermal calculation. The part of the work is also the drawing documentation of the boiler.

Orientador: João Andrade de Carvalho
Resumo: Caldeiras de produção de vapor são utilizadas no setor siderúrgico para produzir e disponibilizar vapor para o processo de geração de energia e para os vários setores que necessitam de aquecimento durante a fabricação de seus produtos, como por exemplo, a vaporização de criogênicos para distribuição na planta. Portanto, caldeiras são equipamentos que necessitam ter confiabilidade. Atualmente, a CSN (siderúrgica brasileira de grande porte) possui duas caldeiras do início da década de 80 que somente partem e operam com uma chama piloto utilizando gás de coqueria, um gás que é subproduto da produção de coque em uma planta siderúrgica. Assim, para alcançar o objetivo de mais confiabilidade e flexibilidade na operação destas caldeiras, utilizou-se os métodos de índice Wobbe, corrigido pela pressão, e o método dos múltiplos índices de Weaver para avaliar a substituição do gás de coqueria pelo gás natural de modo que estas caldeiras possam operar com gás natural em caso de indisponibilidade de gás de coqueria. Mesmo que o aporte energético entre os gases seja diferente, este pode ser ajustado pela pressão do gás. A temperatura de chama adiabática não tem variação significativa, reduzindo-se apenas 1,4%. As emissões de fumaças e CO2 aumentam com a substituição, porém as emissões de NOx tem redução. A utilização do método dos múltiplos índices de Weaver para análise de intercambiabilidade demonstra que o gás natural não é um substituo para um queimador projetado para queimar gás de co... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Steam generators are used in the steel industry to produce and supply steam process for power generation and for other sectors that need heat to manufacture their products, such as the cryogenics vaporization for distribution in the facilities. Therefore, steam generators are equipment that need to have reliability. Currently, CSN (large Brazilian steelmaker) has two steam generators from the early 1980s that only startup and operate with a pilot flame using coke oven gas, a gas that is a byproduct of coke production at a steel plant. Thus, in order to achieve the working objective, reliability and flexibility in the operation of these steam generators, the Wobbe index method, with pressure-corrected, and the Weaver's multiple index method were used to verify the coke oven replacement for natural gas, and then, these steam generators can operate with natural gas in case of coke oven gas unavailability. Results shown in the same way that the energy increase between the gases are different can be adjusted in the pressure reduction. The flame temperature has insignificant variation, only 1.4%. Off gas and CO2 emissions increase with interchangeability. However, NOx emissions are reduced. The Weaver multiple index method for interchangeability analysis demonstrates that natural gas is not a gas to replace coke oven gas in a burner designed to burn coke oven gas, but if the burner is designed to natural gas, coke oven gas may be the substitute gas. Regarding the heat input and pri... (Complete abstract click electronic access below)
Mestre

The diploma thesis deals with design of gas steam boiler with given parameters of steam. Blast furnace and coke oven gas are used as fuel. At the beginning of this work, both co-fired fuels are presented to us, their chemical analysis and stoichiometry are performed. The main part of the diploma thesis deals with the dimensioning of individual heat exchange surfaces such as steam superheaters, evaporators, economizers and air heaters. All heat exchange surfaces meet recommended parameters such as recommended steam rates, flue gas, etc. At the end, the total heat balance of the boiler is performed. Part of the work is also drawing documentation showing the main dimensions of the boiler. It is also indicated the connection of individual heat exchange surfaces.

博士
國立成功大學
化學工程學系
87
Absorption technology has long occupied a crucial position in the industrial gas treatment processes. Refer to the existing absorption problems encountered in the coke-oven gas treatment plant of China Steel Corporation, three absorption topics were defined and studied in this work. They are：(1) surfactant effects on gas absorption under different flow patterns, (2) promotion mechanism for CO2 absorption into dilute aqueous NH3/MEA/DEA solutions, and (3) chemical enhancement for H2S absorption into dilute aqueous NH3 solutions and the effect of NH3 vapor on the acid gas removal by using aqueous NH3 solutions. Detailed understanding of the above absorption topics is both of industrial importance and of academic interest. Four typical types of absorber were designed and built for simulating the necessary absorption condition with diversified flow patterns. Except for the laboratory prepared absorbents, i.e. pure water, surfactant solutions, and chemical absorbents, an industrial absorbent sampling from a coke-oven gas treatment plant was also used in this work. A series of absorption tests were conducted and their corresponding absorption rates were carefully measured. Based on the experimental data and/or the related thermodynamic analysis result, the appropriate quantitative mechanism/expression for every absorption topic was proposed. The effect of organic impurities in industrial stripped coal water (SCW) on the absorption of CO2 was measured experimentally. Removal of these impurities via activated carbon showed a marked improvement in interphase mass transfer of a vertical wetted-wall column absorber. However, this benefit was not found in a stirred-cell absorber, in which different flow pattern from that in wetted-wall column absorber is expected. An ad hoc systematic study on the effects of three deliberately added surfactants on gas absorption by pure water in three different absorbers with different flow patterns was thereafter conducted. The experimental results reveal that absorption deterioration also prevails only in vertical wetted-wall column absorber and the reduction in liquid phase mass transfer by the addition of surfactant can be satisfactorily correlated with surface pressure of solutions. This indicates that the effect of the industrial impurities in SCW on gas absorption may successfully be simulated under the same flow pattern by a surfactant solution with the same surface pressure. A possible modification of the existing coke-oven gas (COG) treatment process for the benefit of absorption enhancement was finally proposed. Chemical enhancement factors for CO2 absorption into dilute aqueous NH3/MEA/DEA solutions in a batch stirred-cell absorber were experimentally determined over a wide range of CO2 loadings. The experimental data are used to examine the validity of two promotion mechanisms: the zwitterion mechanism, by which the carbamate formation is the sole main reaction occurring in the liquid, and the bulk-equilibrium mechanism, by which both the carbamate formation and the carbamate hydrolysis are two fast main reactions to enable the chemical equilibrium to prevail in the bulk-liquid. Concerning the above-mentioned two mechanisms, zwitterion mechanism is the well-known in literature, while the bulk-equilibrium mechanism is proposed in this work. For the absorption of CO2 into partially carbonated aqueous NH3 solutions, the chemical enhancement factors predicted by the bulk-equilibrium mechanism are in good agreement with the experimental data available. In cases of CO2 absorption into dilute aqueous MEA/DEA solutions, the results reveal that the zwitterion mechanism satisfactorily predicts the experimental data for CO2 loadings below 0.3, while the bulk-equilibrium mechanism is more competent in describing those for CO2 loadings larger than 0.5. A detailed rigorous thermodynamic simulation shows that the equilibrium extent of the carbamate hydrolysis, which generates free NH3/MEA/DEA in the bulk and hence promotes absorption, increases with the decrease of the initial amine concentration and with the proceeding of CO2 loadings. The cause of the difference on the appropriate promotion mechanisms for the absorption of CO2 by dilute aqueous NH3/MEA/DEA solutions is explained by the difference on the hydrolysis rates of NH3/MEA/DEA carbamates. Regarding H2S absorption into dilute aqueous NH3 solution, the absorption model based on an irreversible instantaneous reaction has been proved to be appropriate in predicting the chemical enhancement factor. The minor addition of NH3 vapor into the gas phase has experimentally shown a remarkable promotion of CO2 absorption into an aqueous NH3 solution. The absorption model presented in this work can fairly estimate the quantitative extent of this promotion. The result indicates that adding NH3 vapor into the gas phase to accelerate the removal rate of acid gas is practical. Finally, a set of data consisting of the measured composition along three absorbers of a coke-oven gas treatment plant is presented in this work.

碩士
國立中山大學
機械與機電工程學系研究所
104
Carbon accumulation occurs significantly on the walls of inside a coke oven and it may cause serious blocking problems during the coke-making operation. Therefore, the coke oven is scheduled regularly to burn the accumulated carbon under maintenance. Due to the slow combustion rate of deposited carbon, the maintenance time is often long and reduces the yield rate. The study focused on a 3D unsteady coke oven burning model to simulate the real coke oven including heat blocking materials It simulated different convection conditions, which were natural convection, force convection by air blower and force convection by a nozzle pipe, to assist field personnel to select the best operating mode. The burning rate of solid carbon is dominated by the oxygen diffusion, so a forced inflow is proposed to increase the carbon-burning rate. However, if the air inflow rate is too high, it will lower the oven wall temperature and consequently the carbon-burning rate may be slowed down, even terminated. The results showed that more fresh air flow could increase coke burning rate. When flow rate was too high and cool down the oven wall temperature, it may be below the brick safety temperature and the wall brick was damaged. Comparing the simulation results of force convection by air blower and a nozzle pipe, it showed that when the mass flow rate of force convection by a nozzle pipe was 33% smaller than that by air blower, the coke burning rate was 13% higher than force convection by air blower and the burning location was closer to the thicker coke zone. Thus, the method using the forced convection by a nozzle is more time-efficient to coke burning operation. In these three conditions natural convection resulted in an unstable flow field and the coke burning position will change a lot, while the flow field of force convection by air blower could quickly reach a relatively stable state. As a result, a steady state simulation of forced convection by air blower can be used to evaluate the coke burning rate and shorten the simulation time.

碩士
國立成功大學
航空太空工程學系
102
Carbon Deposits are often occurred inside the industrial coke oven during coking process. Accumulation of carbon deposits may cause a big issue, which seriously influences the coking operation. The carbon is burning off by injecting fresh air through pipes into coke oven which is an efficient way practically operated in industries. The burning off carbon deposition in coke oven performed by Computational Fluid Dynamics (CFD) method has provided an evaluation of the feasibility study. A three dimensional, transient, turbulent reacting flow simulation has performed with three different injecting air flow rate and another kind of injecting configuration. The result shows that injection higher air flow rate would effectively reduce the carbon deposits. In the meantime, the opened charging holes would suck extra oxygen from atmosphere to participate in reactions. In term of coke oven operating limits, the wall temperatures are monitored to prevent over-heating of the adiabatic walls during burn-off process. It is demonstrated that the burn-off method by injecting fresh air is feasible to remove the carbon deposits in coke oven. Due to the number of computational nodes being as huge as about 5×10^7, a result at time of 8.3 s would require 3 months computation time in the present study.

碩士
國立成功大學
電機工程學系碩博士班
92
This thesis investigates the characteristics of induction motors (IMs) for driving coke oven plant’s coke transfer cars of China Steel Corporation (CSC). The employed mathematical model and parameters of the studied IMs are very important for performance analyses of the studied system. The induction machine’s q-d axis and a-b-c axis equivalent-circuit models are respectively utilized to analyze both transient and dynamic behaviors of the studied IMs. 　　This thesis discusses and compares the output performance of four independent IMs driven by four independent small frequency converters and four parallel-operated IMs driven by a large frequency converter. By comparing field measured results and computer simulated outcomes, it can be confirmed that the employed model and parameters for the studied IMs are proper and feasible.

碩士
國立高雄第一科技大學
環境與安全衛生工程所
92
Through incomplete burning or pyrolysis, hydrocarbons can produce polycyclic aromatic hydrocarbons (PAHs) that may be carcinogenic or cause mutations. Operators who were persistently exposed to these compounds can cause adverse health effect. Therefore, this study used male laborers who worked at coke ovens and were exposed to PAHs environment as the subjects to investigate the correlations between exposure to PAHs and changes in the quality of semen of laborers. The findings were indicate that the PAHs concentration were 3664.84±3615.56 ng/m3 at oven top that significant higher than 1123.12±1829.28μg/m3 at oven sides，P=0.0022. The percentage of normal morphology of sperm at oven top were significant lower than that workers at oven sides（67.0±5.1﹪to 83.7±3.6﹪, P=0.0010）. The other analysis were not significant include that percentage of abnormal DNA of sperm, concentration of sperm, motility of sperm and the quantity of reactive oxides species. Coke oven workers may work either fixed daytime shift or work in variable morning, afternoon or night shift. So study proceeded to investigate the impact of shift arrangement. The findings indicate that the work-shift pattern also causes significant differences in negative impact on the percentage of normal pattern of semen（P=0.0449）. The percentage of normal pattern of semen of variable shift workers was lower than that of fixed daytime shift workers (i.e. normal shift) （72.1±4.2﹪to 84.7±4.4﹪）.In sperm cell completion（COMP α T）and mitochondria function, normal shift workers are better than variable shift workers, respectively (15.6±2.9 to 26.7±2.8、24.6±2.8 to 16.5±2.7). The exist significant differences, with P being 0.0089 and 0.0400 respectively. To further investigate whether PAHs and work shift pattern had additive consequence on the negative impact on semen, the coke oven workers were divided into four groups, oven side normal shift, oven side variable shift, oven top normal shift, and oven top variable shift, and the oven side normal shift group was designated as the control group. The findings were analyzed and indicate that there exist significant differences in both the percentage of normal morphology of sperm and the percentage of abnormal head of sperm, with P being 0.0306 and 0.0136 respectively. In the percentage of normal pattern of semen, oven side normal shift workers (85.6±7.3﹪) are higher than oven side variable shift workers (80.8±18.5﹪), who are higher than oven top normal shift workers (80.1±11.5﹪), who are higher than oven top variable shift workers (62.7±34.1﹪). These four groups show a decline curve in terms of this percentage. In sum, both PAHs and work shift pattern have negative impacts on the semen of laborers who working at coke ovens; they have consistent negative on the normal pattern percentage of semen and have an additive function trend.

In this study, coke oven tar addition over a range of 0 – 8 wt.% was evaluated as a possible substitute for imported coals fractions. Coke oven tar used was collected from coke oven tar decanters of the by-products section of the coke making plant. Moisture content in coke oven tar varied depending on the residence time and water carryover from coke oven tar separators to storage tanks. Therefore, various moisture ranges were considered in order to observe its effect on coal blend, carbonization and coke properties. The optimum moisture content in coke oven tar was found to be 3% with a coke oven tar addition of 6 wt.% in the coal blend. At the same coke oven tar addition of 6 wt.% in the coal blend but with 6% moisture content in coke oven tar, coke properties improved, coke yield showed up to 4% decrease. On the other hand, with 1% moisture content in coke oven tar of 6 wt.% in the coal blend, coke yield increased by 1% and low coke properties such as I40 of 42.9 and Stability of 50.3 were achieved. The latter process was characterized by excessive increased in wall pressure and pushing energy. Both wall pressure and pushing energy increase are less desirable due to their detrimental effect on the physical condition of the oven walls. Furthermore, addition of coke oven tar with 1% moisture content to coal blend can be prohibited by its high viscosity. At 3% moisture content in coke oven tar addition of 6 wt.% in the coal blend, coke properties improved. When the amount of coke oven tar was increased to 8 wt.% at the optimum coke oven addition, coke yield was not affected but low CSR of 57.8 against a target of ³60 was achieved as opposed to CSR of 65.4 at 6 wt.%. Also, coke stability of 52.2 at 8 wt.% as opposed to 56.1 at 6 wt.% was achieved. Moreover, the highest I40 of 50.9 was achieved at 6 wt.% whereas with 8 wt.% coke oven tar, I40 of 47.9 was achieved. However, up to 2% decrease in coke yield was observed. Despite this 2% decrease in coke yield, coke oven tar addition is a positive and viable option based upon economic factors (i.e. this reduces the quantity and cost of imported coals and still achieves improved coke quality which result in improved blast furnace operation and better hot metal quality).

碩士
國立成功大學
機械工程學系碩博士班
97
In this study, we developed an inspection device protecting a camera inside and sustaining high temperature long enough such that it can be permanently-installed on the pusher ram beam. Note that the temperature of a coking chamber during operation is about 1200 �aC while the maximum tolerable temperature of a camera is less than 40 �aC. The developed device should function as a good thermal insulator and with a cooling device for the camera at the pusher head and for signal cables along the beam. We numerically demonstrated the performance of a proposed inspection device, which can eliminate all concerns above by employing air cooling and thermoelectric coolers. The cooling air is guided into a heat insulated box and divided into two streams. One stream cut off the heat coming from the exterior surface of the box. The other stream was mainly used to discharge the heat from the thermoelectric cooler. In this work, three-dimensional numerical model of the device was built for simulating the temperature distribution inside the device with CFD commercial-available software. The numerical results show that the camera can maintain around 35 �aC during normal operation of coke oven under given conditions. These conditions are: (a) The flow rate of the cooling air is 3~4 Nm3/min and its temperature is 30 �aC; (b) Each thermoelectric cooler requires 45 W as the input power with a heat sink whose heat transfer area is 0.15 m2. In addition, the weight of insulated box is about 10 kg, and its dimensions are 420 mm × 280 mm × 280 mm。

碩士
高雄醫學大學
職業安全衛生研究所碩士班
92
Objective: To study the temporal change of urinary 1-hydroxypyrene (1-OHP) in coke–oven workers after exposed to polycyclic aromatic hydrocarbons (PAHs). Method: From October, 2003 to March, 2004, 18 top-side oven workers and 41 side-oven workers from one coke oven plant of a large steel company were studied. Personal ambient PAHs exposures were measured in the 1st and 6th working days, whereas individual spot urine specimens were collected in the first day before work and after work, the third day after work, and the sixth day before and after work as well as the seventh and eighth day’s morning, and the first day before work in the following working shift. GC/MS and HPLC-FLD were used to measure ambient PAHs and urinary 1-OHP levels. Results: Top-side oven workers were exposed to significantly higher ambient PAHs concentrations than sideoven workers (mean ± SE＝8357.44 ± 4261.46 ng/m3 v.s. 1196.81 ± 265.56 ng/m3, p < 0.001). 1-OHP concentrations in the first day before work were significant higher in top-side oven workers than in sideoven workers (mean ± SE＝236.23 ± 70.00 v.s. 35.17 ± 9.93μg / g creatinine, p < 0.001). Among the top-side oven workers, the trend of 1-OHP increased sharply from the first day before work and became a plateau in the sixth day before (443.67 ± 125.47 μg / g creatinine)and after work (424.62 ± 91.43μg / g creatinine). And it declined dramatically in the 8th day morning(201.53 ± 49.41μg / g creatinine). In contrast, in sideoven workers, 1-OHP concentrations increased slowly and reached to the top in the third day after work(70.54 ± 13.09μg / g creatinine) and the sixth day before work (61.93 ± 10.52μg / g creatinine). Conclusion: Top-side oven workers were exposed to significantly higher ambient PAHs concentrations than sideoven workers. The excretion of 1-OHP was also significantly higher in top-side oven workers than sideoven workers. In addition, the patterns of the temporal change of 1-OHP concentrations in top-side oven workers and sideoven workers were different.

The effect of microwave radiation on the prepared 0.5Fe/ZSM-5 catalysts as a post-synthesis modification step was studied in the methanol-to-hydrocarbons process using the temperature-programmed surface reaction (TPSR) technique. This was achieved by preparing a series of 0.5Fe/ZSM-5 based catalysts under varying microwave power levels (0–700 W) and over a 10 s period, after iron impregnating the HZSM-5 zeolite (Si/Al = 30 and 80). Physicochemical properties were determined by XRD, SEM, BET, FT-IR, C3H9N-TPSR, and TGA techniques. It was found that microwave radiation induced few changes in the bulk properties of the 0.5Fe/ZSM-5 catalysts, but their surface and catalytic behavior were distinctly changed. Microwave radiation enhanced crystallinity and mesoporous growth, decreased coke and methane formation, decreased the concentration of Brønsted acidic sites, and decreased surface area and micropore volume as the microwave power level was increased from 0 to 700 W. From the TPSR profiles, it was observed that microwave radiation affects the peak intensities of the produced hydrocarbons. Application of microwave radiation shifted the desorption temperatures of the MTH process products over the HZSM-5(30) and HZSM-5(80) based catalysts to lower and higher values respectively. The MeOH-TPSR profiles showed that methanol was converted to DME and subsequently converted to aliphatic and aromatic hydrocarbons. It is reasonable to suggest that microwave radiation would be an essential post-synthesis modification step to mitigate coke formation and methane formation and increase catalyst activity and selectivity.
Chemical Engineering
M. Tech. (Chemical Engineering)