No description available.

Voir résumé étendu en français en fin de thèse. / In the actual energetic and economic context, energy polygeneration represents the answer regarding the efficient use of a fuel. This solution would diminish the losses associated to the classical methods of energy production and, as a result, would increase the installations' efficiency. The polygeneration systems (cogeneration/trigeneration of energy), consist of various technologies that offer alternatives to the global problems linked to energy, such as energy scarcity, energy supply security, emissions control from the production of energy, economy and energy conservation, etc.. This doctoral thesis examines two types of polygeneration of energy. The first part focuses on the analysis of a high power trigeneration system based on a gas turbine installation for production of electrical energy, the second part of the thesis is dealing with a system of micro-cogeneration of energy powered by a solar Stirling engine. Given the actuality and interest for the polygeneration field of energy production, there is a constant concern to simulate and optimize the operation of this kind of systems in order to achieve significant performance designed to satisfy the consumers' needs

The thesis is devoted to the utilisation of expansion turbines in the thermal power stations and in the industry companies using gas pressure reduction for technology purposes. The theoretic part of this thesis deals with the technology equipment such as steam and gas turbines, generators and reduction stations. The special attention is given to the expansion turbines with regard to its dividing in two groups: for steam reduction and for gas reduction. The parctical part includes the preliminary and detailed calculation of the expansion turbin for parameters of reduction line for combustion turbines, the generator proposal and the possibility of power extraction. The economic part completes the thesis with the economic evaluation of investment efficiency.

This thesis deals with the characteristics of natural gas and the problems of transport. Furthermore, this work deals with the most commonly used thermodynamic cycles, both steam and gas and their applications in the energy industry. The main part of this thesis focuses on the calculation of the thermodynamic properties of the gas, determine the minimum temperature gas after expansion in the turbine to prevent the formation of hydrates, design calculation of main dimensions and thermodynamic parameters of the expansion turbine on natural gas. As a final design will be drawn slice computed expansion turbine.