The control of particle emissions from an oil refinery is often difficult, due to changing operational conditions and the limited range of available treatment options. Excessive particle emissions have often been attributed start up problems with Fluidized Catalytic Cracker Units (FCCU) and little information is available regarding the exact composition and nature of these excessive emissions. Due to the complex nature of a FCCU, it has in the past been difficult to identify and control emissions, without the use of expensive end of pipe technologies. An Australian Oil Refinery, concerned with their catalyst emissions, sponsored this study of FCCU particle emissions. Due to the industrial nature of the project, a holistic approach to the management of emissions was taken, instead of a detailed investigation of a single issue. By looking at the broader range of issues, practical and useful outcomes can be achieved for the refinery. Initially, detailed emissions samplings were conducted to investigate the degree of particle emissions under start up conditions. Stack emissions were collected during a standard start up, and analysed to determine the particle size distribution and metal concentration of the emitted material. Three distinct stages of emissions were discovered, initially a high concentration of larger particles, followed by a peak in the very fine particles and finally a reduction of particle emissions to a more steady or normal operational state. The variation in particle emissions was caused by operational conditions, hardware design and catalyst characteristics. Fluctuations in the gas velocity through the system altered the ability of the cyclones to collect catalyst material. Also, the low bed level allowed air bypass to occur more readily, contributing to the increased emissions levels seen during the initial stage of the start up. Reduced fluidity characteristics of the circulating catalyst also affected the diplegs operations, altering the collection efficiency of the cyclone. During the loading of catalyst into the system, abraded material was quickly lost due to its particle size, contributing to fine particle emissions levels. More importantly, thermal fracturing of catalyst particles occurred when the cold catalyst was fed into the hot regenerator. Catalyst particles split causing the generation of large amounts of fine particle material, which is easily lost from the system. This loading of catalyst directly linked to the period of high concentration of fine particles in the emissions stream. It was found that metals, and in particular iron, calcium and silicon form a thick layer on the outside of the catalyst, with large irregular shaped metal ridges, forming along the surface of the particle. These ridges reduce the fluidity of the catalyst, leading to potential disruptions in the regenerator. In addition to this, the metal rich ridges are preferentially removed via attrition, causing metal rich material to be emitted into the atmosphere. To overcome these high particle emissions rates from the FCCU the refinery should only use calcinated catalyst to reduce the influence of thermal process and particle fracture and generation. Although the calcinated catalyst can fracture when added to the system, it is far less than that obtained with uncalicinated catalyst. To further reduce the risk of particle fracture due to thermal stresses the refinery should consider reducing the temperature gradients between the hot and cold catalyst. Due to the economics involved with the regenerator, possible pre-warming of catalyst before addition into system is the preferred option. This pre-heating of catalyst should also incorporate a controlled attrition stage to help remove the build up of metals on the surface of the particles whilst allowing this material to be collected before it can be released into the atmosphere. The remove of the metal crust will also improve the fluidity of the system and reduce the chance of catalyst blockages occurring. Finally, modelling of the system has shown that control of key parameters such as particle size and gas velocity are essential to the management of air emissions. The refinery should look at adjusting start up procedures to remove fluctuations in these key parameters. Also the refinery should be careful in using correlation found in the literature to predicted operational conditions in the system as these correlations are misleading when used under industrial situations.

This diploma thesis should bring not only working machine into the branch of agricultural industry, but also new approach to design. Obviously, the contribution of technical innovations, which are required in this segment, is concerned, too. All knowledge and concepts come from the practise of this field. The project partly takes up the pre-diploma thesis called Vision of the agricultural cutting machine with container arrangement and shares some details of the concept as such. The technical part was solved during the winter term within the scope of the subject Machines and equipment. From this project will be adopted all bases of constructional innovations of agricultural machine concept.

No description available.

L’objectif de ce mémoire de maîtrise est de développer et de caractériser diverses sources de neutres réactifs destinées à des études fondamentales des interactions plasmas-surfaces. Ce projet s’inscrit dans le cadre d’une vaste étude de la physique des interactions plasmas-parois mises en jeu dans les procédés de gravure par plasma des matériaux de pointe. Une revue de la littérature scientifique sur les diverses méthodes permettant de générer des faisceaux de neutres réactifs nous a permis de sélectionner deux types de sources. La première, une source pyrolitique, a été caractérisée par spectrométrie de masse en utilisant le C2F6 comme molécule mère. Nous avons montré que le C2F6 était dissocié à plus de 90% à 1000ºC et qu’il formait du CF4, lui-même dissocié en CF2 vers 900ºC. Ces résultats ont été validés à l’aide d’un modèle basé sur des calculs d’équilibres chimiques, qui a aussi prédit la formation de F à 1500ºC. La seconde source, un plasma entretenu par une onde électromagnétique de surfaces, a été caractérisée par spectroscopie optique d’émission et par interférométrie haute fréquence. Dans le cas du plasma d’argon créé par un champ électromagnétique (>GHz), nos travaux ont révélé une distribution en énergie des électrons à trois températures avec Te-low>Te-high<Te-tail. Nous avons conclu que la formation d’électrons suprathermiques était liée à la génération d’instabilités de plasma au point de résonance au voisinage des parois du réacteur et à des mécanismes d’amortissement de ces instabilités de type Landau. Le même phénomène a été observé dans le plasma de Cl2, mais cet effet disparaissait pour des pressions élevées du au fait de l’amortissement collisionnel. Nous avons aussi montré que ces sources pouvaient conduire à des degrés de dissociation du Cl2 près de 100%. / The goal of this Master thesis goal is to develop and characterize different sources of reactive neutrals aimed at fundamental studies of plasma-surface interactions. This project is part of a broader study on the physics driving plasma-wall interactions during plasma etching of advanced materials. Following our literature review of the various approaches used to generate radical beams, we have selected two types of sources. The first one, a thermal cracker, was characterized by line-of-sight mass spectrometry using C2F6 as the mother. We have shown that more than 90% of the C2F6 was dissociated at 1000ºC, producing CF4 that dissociates into CF2 at temperatures close to 900ºC. These results were in good agreement with the predictions of a model based on chemical equilibrium calculations, which also predicted the formation of F radicals at 1500 ºC. The second source, a surface-wave plasma, was characterised by optical emission spectroscopy and microwave interferometry. For a high-frequency (>1GHz) argon plasmas, we have shown a three temperature electron energy distribution function with Te-low>Te-high<Te-tail. We have concluded that the formation of suprathermal electrons was linked to the generation of plasma instabilities at the resonance point near the chamber walls, and to Landau damping of these instabilities. The same phenomenon was observed in Cl2 plasma, but this effect vanished at high pressures because of collisional damping. We have shown that this type of source could produce near 100% dissociation of Cl2, depending on operating conditions.

L’objectif de ce mémoire de maîtrise est de développer et de caractériser diverses sources de neutres réactifs destinées à des études fondamentales des interactions plasmas-surfaces. Ce projet s’inscrit dans le cadre d’une vaste étude de la physique des interactions plasmas-parois mises en jeu dans les procédés de gravure par plasma des matériaux de pointe. Une revue de la littérature scientifique sur les diverses méthodes permettant de générer des faisceaux de neutres réactifs nous a permis de sélectionner deux types de sources. La première, une source pyrolitique, a été caractérisée par spectrométrie de masse en utilisant le C2F6 comme molécule mère. Nous avons montré que le C2F6 était dissocié à plus de 90% à 1000ºC et qu’il formait du CF4, lui-même dissocié en CF2 vers 900ºC. Ces résultats ont été validés à l’aide d’un modèle basé sur des calculs d’équilibres chimiques, qui a aussi prédit la formation de F à 1500ºC. La seconde source, un plasma entretenu par une onde électromagnétique de surfaces, a été caractérisée par spectroscopie optique d’émission et par interférométrie haute fréquence. Dans le cas du plasma d’argon créé par un champ électromagnétique (>GHz), nos travaux ont révélé une distribution en énergie des électrons à trois températures avec Te-low>Te-high<Te-tail. Nous avons conclu que la formation d’électrons suprathermiques était liée à la génération d’instabilités de plasma au point de résonance au voisinage des parois du réacteur et à des mécanismes d’amortissement de ces instabilités de type Landau. Le même phénomène a été observé dans le plasma de Cl2, mais cet effet disparaissait pour des pressions élevées du au fait de l’amortissement collisionnel. Nous avons aussi montré que ces sources pouvaient conduire à des degrés de dissociation du Cl2 près de 100%. / The goal of this Master thesis goal is to develop and characterize different sources of reactive neutrals aimed at fundamental studies of plasma-surface interactions. This project is part of a broader study on the physics driving plasma-wall interactions during plasma etching of advanced materials. Following our literature review of the various approaches used to generate radical beams, we have selected two types of sources. The first one, a thermal cracker, was characterized by line-of-sight mass spectrometry using C2F6 as the mother. We have shown that more than 90% of the C2F6 was dissociated at 1000ºC, producing CF4 that dissociates into CF2 at temperatures close to 900ºC. These results were in good agreement with the predictions of a model based on chemical equilibrium calculations, which also predicted the formation of F radicals at 1500 ºC. The second source, a surface-wave plasma, was characterised by optical emission spectroscopy and microwave interferometry. For a high-frequency (>1GHz) argon plasmas, we have shown a three temperature electron energy distribution function with Te-low>Te-high<Te-tail. We have concluded that the formation of suprathermal electrons was linked to the generation of plasma instabilities at the resonance point near the chamber walls, and to Landau damping of these instabilities. The same phenomenon was observed in Cl2 plasma, but this effect vanished at high pressures because of collisional damping. We have shown that this type of source could produce near 100% dissociation of Cl2, depending on operating conditions.

近年來，隨著能源價格不斷飆漲以及溫室氣體大量排放造成的氣候異常變化，引起世界各國對於提高能源使用效率與加強溫室氣體排放管制的重視。溫室氣體大多由化石燃料燃燒所產生。因此，一般被視為能耗較高的發電、鋼鐵、水泥以及石化等產業，遂成為眾所矚目而被要求加強溫室氣體排放管制的主要產業。未來的產業發展規劃，必需兼顧經濟與環保，否則必將被世界潮流所淹沒。 因應全球溫室氣體排放管制趨勢，就台灣經濟發展面、財政建設面、環境永續經營面等層面考量分析，現階段石化產業之發展應對產業競爭力及環境保護做更多且更審慎的考量。於產業競爭力部分，建議中油開放民營，並運用部份釋股取得的資金，一方面引進先進的製程技術及進行設備更新，提升企業競爭力；另一方面整合國內仰賴台灣中油公司供料且在各產品領域擁有數十年營運經驗的中下游業者，建構泛中油體系的石化經營團隊。如此泛中油體系與國內另一石化產品鏈已相當完整的台塑體系，形成兩大石化體系，互為良性競爭。於環境保護方面，則建議我國應終止國光石化投資案，降低溫室氣體排放量，並藉提升廠商製程效率減少能耗，如此將使經濟發展及環境保護得以兼顧，亦達成原興建國光計畫之目的。 而未來台灣石化產業發展策略，技術發展需長期向下扎根，產品則朝高值化、精緻化發展，開發低能耗、低污染之替代能源，提升產品的附加價值，並將大宗石化耗能的產品移往海外能源低廉的地區，持續提升產業競爭力，並達成溫室氣體減少排放為目標。如是，台灣在環境保護日益重視之趨勢下，石化產業也得以永續發展。 / The high energy cost and the unusual climate change due to increasing green house gases（GHG）emission in recent years have attracted the global attentions and called for improvement of energy utilization efficiency and enhancement of GHG emission control. GHG are mostly produced by the combustion of fossil fuels. And the higher energy consumption industries such as power generation, steel, cement and petrochemical industries are thus strongly requested to reduce GHG emission. Economic development and environmental protection both are needed to be equally evaluated in the planning of future industry development. Taking petrochemical industry as an example, many of its mid-stream and down-stream products have become an unseparable part and of our daily life. In Taiwan, it has been over half century since the establishment of petrochemical industry, and now become top 10 petrochemical production countries in the world. The production value of petrochemical-related industries are very close to 4 trillion NT dollars, about 30% of total production value of domestic manufacturing sectors. Petrochemical industry and electronic industry are the two strong arms in supporting national economic growth. As a very important industry in Taiwan, however, the intensity of its GHG emission is only next to steel industry. The significant technology improvement in petrochemical industry has been achieved since the installation of the existing refinery, naphtha crackers and many petrochemical mid-stream production plants in Taiwan. It is well recognized that the GHG emission will be greatly reduced if the advanced technologies are introduced and the old facilities are revamped. Therefore, the writer would like to address a different approach toward KuoKuang Petrochemical Project which the government is giving an impetus to its execution. Here the writer would propose Taiwan CPC company, the state-owned petroleum company and the leader of Kuokuang Petrochemical Project, to become privatized after asset re-evaluation and collect some government capital from privatization through issuance of part of its shares to the open market. The capital thus collected can be used for enterprise reform. The important items of the enterprise reform include but not limited to introduction of the advanced technologies, revamping of existing facilities and establishment of a new well-integrated petrochemical conglomerate through mutual investment between Taiwan CPC and the mid-stream companies that rely raw material supplies from Taiwan CPC. From viewpoints of both economy and environment, government policy of implementation of KuoKuang Petrochemical Project is worthy for reconsideration. Formation of a CPC-lead petrochemical conglomerate would also benefit the current petrochemical companies that rely on raw material supplies from Taiwan CPC as their operation efficiencies would improved from business intergration. The newly formed conglomerate would be more powerful in further business development and more competitive in world market. They would have more resources to explore their potential in advanced technology development, in new business fields such as biomass energy, solar energy and so on. The CPC-lead petrochemical conglomerate would be able to enchance its competitiveness to another domestic petrochemical giant, Taiwan Formosa Group, and other petrochemical giants in the global market.