Research Of Performance Calculation Model In Cogeneration Units

To pay equal attention to developing and economizing and to give the highest priority to energy-saving is our country's energy policy. Cogeneration, which can be of great benefit to economy and society, plays an important role in primary energy source economizing. But along with the electric power market extending gradually and the competitions increasing vigorously, managers of power plants can not only keep the units working orderly, they also want to keep the units at the best, the most stable and the most economic state.The thesis focus on the general mathematical model of thermodynamic system, the model of economic performance, real-time performance monitoring as well as energy-loss analysis. The main contents are as follows:Thermal economic performance calculation for thermodynamic system is the basic method in designing thermodynamic system, analyzing and directing units operated safely and economically in thermal power plants. The method of cycle function for thermodynamic system and it's general computing formula has been discussed in detail. This method has divided the whole system cycle into several sub cycles, so that all sub cycles own their general computing formula in express. Therefore, local quantitative calculation and characteristic index calculation of each sub cycle, on which the development of general software is based, can be realized. This thesis also work over the characteristic equations and characteristic parameters for cogeneration units, analyze the basic off-design theory and calculating process(in variable parameter condition)at length and discuss the application of equations and parameters for off-design calculation.Applying the concepts of modular modeling, based on "method of cycle function"- thermodynamic system analysis and calculation theory, the forms of typical heater units and auxiliary cycles have been classified comprehensively, and the model database as well as configuration system has been established and realized. The thermal economic analysis software has been designed and developed on the base of the idea above mentioned. Combined with project practice, this software can apply to cogeneration units and fossil-fired generating units. And it has better expansibility, which can meet the need of increasingly more complex thermal generating systems. So it can be used to provide advice on economic operation of units and also can be used to reflect real-time thermal economic performance. A comparatively complete thermal economic index has been established in this paper, which lays the foundation for quantitative analysis. It is very convenient to obtain the cogeneration-generating ration by cycle function method, which gives the effective support to the traditional energy-saving index system. Integrated with development and application of real-time performance monitoring, a comparatively complete mathematical model adapted to the spot is put forward. At the same time, a energy-loss model based on current operating parameter condition is also educed, as well as the framework of the real-time energy-loss analysis system.