For more than 20 years, cap-and-trade system has served as an efficient market-based mechanism to reduce emission of air pollutants such as sulfur dioxide and greenhouse gas. In this system, a limited amount of emission allowances are traded between affected firms with no price restriction. A potential problem arises when market demand of the allowances significantly surpasses market supply: allowance prices could boom to unexpected high level that jeopardizes the overall economy. Safety valve, an innovative mechanism, sets an upper limit of the allowance price and eliminates the risk of allowance price spike. Yet individual firms would bear less incentive to undertake substantial investment in costly emission reduction equipment. This paper analyzes how firms would change their investment strategy when we add a safety valve to a cap-and trade system. Since the allowance price evolution process is time dependent and does not follow the standard Geometric Brownian Motion, there is no analytical solution to this problem, hence we base our analysis on numerical analysis. Using a lattice model, we conclude that a safety valve would undoubtedly delay firms’ actual investment in emission reduction equipment. We also conduct sensitivity tests to analyze how would a firm’s investment strategy respond to change in some model parameters.

For more than 20 years, cap-and-trade system has served as an efficient market-based mechanism to reduce emission of air pollutants such as sulfur dioxide and greenhouse gas. In this system, a limited amount of emission allowances are traded between affected firms with no price restriction. A potential problem arises when market demand of the allowances significantly surpasses market supply: allowance prices could boom to unexpected high level that jeopardizes the overall economy. Safety valve, an innovative mechanism, sets an upper limit of the allowance price and eliminates the risk of allowance price spike. Yet individual firms would bear less incentive to undertake substantial investment in costly emission reduction equipment. This paper analyzes how firms would change their investment strategy when we add a safety valve to a cap-and trade system. Since the allowance price evolution process is time dependent and does not follow the standard Geometric Brownian Motion, there is no analytical solution to this problem, hence we base our analysis on numerical analysis. Using a lattice model, we conclude that a safety valve would undoubtedly delay firms’ actual investment in emission reduction equipment. We also conduct sensitivity tests to analyze how would a firm’s investment strategy respond to change in some model parameters.

This research project was carried out at the von Karman Institute for Fluid Dynamics (VKI), in Belgium, in collaboration and with the funding of Centre Technique des Industries Mécaniques (CETIM) in France.<p>The flow of a mixture of two fluids in pipes can be frequently encountered in nuclear, chemical or mechanical engineering, where gas-liquid eactors, boilers, condensers, evaporators and combustion systems can be used. The presence of section changes or more generally geometrical singularities in pipes may affect significantly the behavior of twophase flow and subsequently the resulting pressure drop and mass flow rate. Therefore, it is an important subject of investigation in particular when the application concerns industrial safety valves.<p>This thesis is intended to provide a thorough research on two-phase (air-water) flow phenomena under various circumstances. The project is split in the following steps. At first, experiments are carried out in simple geometries such as smooth and sudden divergence and convergence singularities. Two experimental facilities are built; one in smaller scale in von Karman Institute and one in larger scale in CETIM. During the first part of the study, relatively simple geometrical discontinuities are investigated. The characterization and modeling of contraction and expansion nozzles (sudden and smooth change of section) is carried out. The pressure evolution is measured and pressure drop correlations are deduced. Flow visualization is also performed with a high-speed camera; the different flow patterns are identified and flow regime maps are established for a specific configuration.<p>A dual optical probe is used to determine the void fraction, bubble size and velocity upstream and downstream the singularities.<p>In the second part of the project, a more complex device, i.e. a Safety Relief Valve (SRV), mainly used in nuclear and chemistry industry, is thoroughly studied. A transparent model of a specific type of safety valve (1 1/2" G 3") is built and investigated in terms of pressure evolution. Additionally, flow rate measurements for several volumetric qualities and valve openings are carried out for air, water and two-phase mixtures. Full optical access allowed identification of the structure of the flow. The results are compared with measurements performed at the original industrial valve. Flowforce analysis is performed revealing that compressible and incompressible flowforces in SRV are inversed above a certain value of valve lift. This value varies with critical pressure ratio, therefore is directly linked to the position at which chocked flow occurs during air valve operation. In two-phase flow, for volumetric quality of air=20%, pure compressible flow behavior, in terms of flowforce, is remarked at full lift. Numerical simulations with commercial CFD code are carried out for air and water in axisymmetric 2D model of the valve in order to verify experimental findings.<p>The subject of modeling the discharge through a throttling device in two-phase flow is an important industrial problem. The proper design and sizing of this apparatus is a crucial issue which would prevent its wrong function or accidental operation failure that could cause a hazardous situation. So far reliability of existing models predicting the pressure drop and flow discharge in two-phase flow through the valve for various flow conditions is questionable. Nowadays, a common practice is widely adopted (standard ISO 4126-10 (2010), API RP 520 (2000)); the Homogeneous Equilibrium Method with the so-called !-method, although it still needs further validation. Additionally, based on !-methodology, Homogeneous Non-Equilibrium model has been proposed by Diener and Schmidt (2004) (HNE-DS), introducing a boiling delay coefficient. The accuracy of the aforementioned models is checked against experimental data both for transparent model and industrial SRV. The HNE-DS methodology is proved to be the most precise among the others. Finally, after application of HNE-DS method for air-water flow with cavitation, it is concluded that the behavior of flashing liquid is simulated in such case. Hence, for the specific tested conditions, this type of flow can be modeled with modified method of Diener and Schmidt (CF-HNE-DS) although further validation of this observation is required. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

[pt] Os desafios na construção de poços de petróleo vêm aumentando ao longo do tempo, seja pelo aumento das dificuldades técnicas devido à maior complexidade das áreas a serem desenvolvidas, sejam pelas melhorias nas regras dos órgãos reguladores visando aumentar a segurança. Existem dois pilares que devem nortear um projeto de um poço de petróleo: segurança e produtividade. O equipamento denominado dispositivo de segurança de sub-superfície e seu sistema de controle podem ser considerados importantes para os dois, pois caso o sistema falhe, obtendo-se um fechamento prematuro do poço, afetará diretamente a produção. Por outro lado, caso a falha ocorra em uma tentativa de fechamento, poderá influenciar nas consequências de um desastre, o que afetaria tanto pessoas como o meio ambiente. O objetivo deste estudo e comparar a confiabilidade de alguns modelos de sistemas de controle do dispositivo de segurança de sub-superfície, levando em consideração as disposições dos equipamentos ao longo do sistema e suas respectivas taxas de falha. Além disso, a maioria dos estudos de confiabilidade realizados nesta área tem como foco principal a segurança, porém este estudo visa obter um foco de eficiência de produção, e as análises serão baseadas em comparações entre algumas configurações disponíveis do sistema, entre componentes em série e em paralelo, utilizando o modelo de análise de confiabilidade markoviano. / [en] The challenges in well construction have been increasing over time, sometimes by increasing the technical difficulties due to the greater complexity of the areas to be developed, sometimes by the improvements in the rules of regulatory agencies to increase security. There are two pillars that should guide the project of a petroleum well: safety and productivity. The equipment called Subsurface Safety Valve and its control system can be considered important for both pillars, because if the system fails resulting in a premature well closure, it will directly affect the production. On the other hand, if the failure occurs in an attempt to closing it, may influence the consequence of a disaster, which would affect both people and the environment. The objective of this study is to compare the reliability of some control systems models taking into account the equipment positions throughout the system and their failure rates. Furthermore, most reliable studies conducted in this area has mainly focused on safety, but this study has a focus on production efficiency, and the analysis will be based on comparisons between some configurations available for subsurface safety valves control system, including serial and parallel components, using the model of Markov reliability analysis.

In this thesis I review the sufficient flow capacity of the safety valve against high-pressure heater thermal pressurization in high-pressure feedwater heater on nuclear power Dukovany. I present basic possible cases of thermal pressurization both a high node heater, and the extended pressure unit in case of closure all power heads to steam generators.

Theme of diploma thesis is the heating of the indoor swimming pool. The thesis is departed to three parts. In the first part, there is a theoretical solution indoor climate of swimming pool. In the second part, there is a calculation solution of the project. Project solves heating of the indoor swimming pool. The last part is an experimental part. Theme of the experiment is measurement of temperature and relative humidity of the swimming pool.

The subject of this thesis is energy storage systems in building services. In the first part the theoretical acquaintance with the nature of energy storage. In the second part has two variants preparation hot water in an apartment building. In the third part of the test solution storage tank of hot water. Development of computational algorithms, comparison of calculation used and the final summary.

The theoretical part of the thesis deals with the hydraulics of heating systems. The aim of the project is a design of the heating and hot water preparation system for an apartment building. The building has 6 above-ground floors and 2 underground floors. Two different options of heating systems were designed, comparison and results are presented in the thesis. In the first case the heat source during the winter season and for water heating, where chosen two gas condensing boilers, situated in separated room on the second underground floor. In the second case, each apartment has its own gas condensing boiler. The experimental part of the project deals with measurements of pressure losses in water armatures used in heating systems. The aim of this part is the determination of coefficients of added resistance for uncontrolled elements, which are normally presented as tabular value. In thesis are presented results for a ball valve, backflow preventer, filter, for slide valve and thermostatic valve. Measurements for thermostatic valve where done with different settings and results are compared with parameters listed in the datasheet.