Research On Characteristic Of Operation Mode Of Steam Turbine Unit Based On Exergy Analysis

With the development of the times, the energy gradually became an important material basis for human survival and development, and in today’s increasingly tense energy, energy saving becomes an important part of a large thermal power plant. When running in steam turbine under variable conditions affect the heat economy of the main factors include: System design, equipment condition, operation mode, the operating environment and the operators skill levels, of which only run as a deliberate change. Therefore, the unit operating optimization management, looking for optimal operation mode, reduce the large-scale thermal power production costs and enhance competitiveness in important ways. Now based on the first law of thermodynamics study on heat balance analysis methods in unit operation mode, comprehensive preparation program, combined with sophisticated measurement and control technology, has been basically realized automation of thermal performance analysis, online, real-time. But based on the second law of thermodynamics for exergy analysis method is rarely seen, so take advantage of exergy analysis of unit operating optimization is necessary.This article is based on the second law of thermodynamics, takes the typical steam turbine unit for research and analysis. Establishment of general physical model for the steam turbine generator set, deriving the steam turbine exergy loss and exergy efficiency of general matrix equation, analyzing the changes of single factor which is one of the main parameters at the inlet and outlet of the steam turbine. Using the MATLAB software, under the 100%, 75%, 50%, 40%, 30% rated conditions respectively to calculate the steam turbine exergy loss and exergy efficiency, analysis of the exergy loss and exergy efficiency change trend of the steam turbine cylinder and the whole steam turbine under the setting pressure and sliding pressure operation conditions, found with the loss of the unit load, the whole steam turbine exergy efficiency gradually reduce in the setting pressure; increased slightly at first and then gradually reduced in the sliding pressure, but trends were not evident. After that to calculate the two sets of the same type steam turbine unit, compared the exergy efficiency change of the two unit, put forward the operation pressure which is the main factors affecting of the unit exergy efficiency for the variable load operation, provide the exergy analysis theory basis for the steam turbine operation optimization, provide effective ways for the daily operation and management of the large thermal power unit.