Optimisation des cycles de liquéfaction du gaz naturel.

Abstract

The work presented in this thesis is a contribution to the study of the production of electricity by a hybrid thermal power plant exploiting the solar field on the one hand and natural gas on the other hand. This work concerns firstly the evaluation of the thermodynamic performances of a solargas hybrid thermal power system with a power of 150 MW, the method of energy analysis was used in this thesis. This method is used to determine the main parameters in order to achieve improvements in system performance. The development of the analysis model in this thesis is carried out by determining the thermal and solar efficiency as well as the efficiency of solar electricity. Due to the calculation of the thermal and solar performances in typical days and an average of the days of the year, we used simulation software "Aspen Plus" to determine the thermodynamic parameters of the hybrid plant in the case of Algerian weather conditions. As well as the System Advisor Model (SAM), this gives a methodology and information particularly on cylindro-parabolic shapes concerning the part of the solar field in the system studied. The results are calculated hour by hour from sunrise to sunset. The second part of this work is being improved in the overall efficiency of the plant with two levels of pressure that directly affects the capacity of the steam turbine in the power block. In the third part, an optimization of the power at the level of the steam turbine is also carried out. The optimization was carried out in the power block which contains two gas turbines and a double pressure steam cycle where the high pressure part is only heated. Preliminary simulations for this system have shown that the steam turbine cycle can achieve optimum conditions for reheating and low vapor pressure, which would enhance the performance of the system. The fourth part concerns the comparison of the key parameters of the thermal power plant in different sites based on the economic factor (LCOE), the configuration of the solar field section and the line spacing or the so-called effect of shading. The exploitation of the "Aspen plus" and "SAM" software enabled us to establish models of optimal hybrid power plants (solar-gas) in the arid zone of Algeria. Such a study is a reference for the construction and site selection of the installation of this type of power plant.