The Thermal Performance Calculations Of Combined Cycle Heat Recovery Steam Generator On The Basis Of Environmental Temperature Variation

Gas Steam Combined Cycle (GSCC) has been widely applying. In this system, Heat Recovery Steam Generator (HRSG) is restricted by the parameters of exhaust from gas turbine, the thermal characters of steam is also affected by HRSG meanwhile, and the flue gas resistance numerical value of HRSG has the direct effect on the power and efficiency of gas turbine, which influences the whole efficiency of GSCC importantly. In this thesis, the 100% load of gas turbine exhaust working conditions were formulated considering the characters of local environmental temperature variation, basing on the optimization of steam parameters to a given HRSG at 100% load, the thermal and flue gas resistance calculations of this HRSG were carried out on the basis of environmental temperature variation.In this thesis, the principles and characters of three basic types of GSCC were introduced, the qualitative Thermodynamics and application evaluations were carried out firstly, which settled the base for the future research. Then the energy of the GSCC system with Low-Pressured Evaporator (LEP),Supplementary-Firing Burner Unit (SFBU) and single- pressured HRSG was integrated, and two expressing formulas of the former system power supply efficiency were achieved by the basic theory of Thermodynamics and mathematic deducing. Taking the max power supply efficiency of Combined Cycle when HRSG without SFBU as the objective function, basing on the analyses of Thermodynamics and engineering project restraints, using the thermal models of this HRSG and steam gas turbine, taking the given exhaust parameters of coming into this HRSG as original data, the steam parameters of this HRSG were optimized calculated, and the results were analyzed, compared and selected, which were used as the basis for the thermal performance calculations of this HRSG. In the end, the model of reducing superheated steam temperature with saturated steam was built. An equal quantity relationship equation of superheater thermal balance equation was deduced from the thermal and mass balance equations of the reducing temperature model. Basing on the former work, the thermal calculation method and steps on superheater were introduced in detail, which was combined with the built thermal model of this HRSG, the related contents of the standard calculation method and the experimental data from engineering project, thus the calculation method for this HRSG was gained, the thermal and flue gas resistance calculations in the formulated working conditions of this HRSG were carried out.The conclusions gained through analyses and calculations in this thesis as follows:the rationality of thermal calculation method and the arrangement of heating surfaces for this HRSG; the applicability of thermal calculation method and the models of steam parameters optimization; the instructive functions to other calculations, design and operation of this HRSG; the numerical value of superheater exit steam temperature, the flux of saturated ste(?)m used for reducing superheated steam temperature and this HRSG flue gas resistance as well as their regular patterns along with gas turbine exhaust gas temperature variation.