The Design Of Boiler Monitoring Instrument Based On Fieldbus

As an important part of the generator performance monitoring, the boiler performance monitoring system provides the intuitive and accurate judgment for operating. Many power plants due to the current economic considerations in the combustion of coal or mixed low-quality coal, so coal quality parameters seriously deviate from the design coal, it not only has a significant impact on the safe and economic operation of the unit,but also makes a chanllenge to performance monitoring.This paper puts forward a method of on-line calculation of coal quality parameters and boiler efficiency, combined with the popular ARM embedded technology and the fieldbus communication. We have designed and developed a highly meaningful boiler monitoring instruments, providing a reliable guide for operating personnel and reaching optimization, energy-saving purposes.The main contents and results are as follows:(1) A calculation of gas based on the calorific value of coal and calculation of enthalpy-temperature chart is proposed to improve and simplify the calculation of boiler heat losses and anti-balance efficiency. According to flow and heat transfer mechanism which simplifies the calculation process reheat steam flow;According to the boiler efficiency balance between positive and negative we proposed a model of on-line calculation of coal quality parameters and boiler efficiency.Two invention patents have been applied.(2) Considered in the actual needs of power plant boiler performance monitoring,design principles of instruments based on fieldbus is proposed and we complete the instrument functional requirements analysis.(3) Hardware and software development has been completed,which based on functional requirements analysis completed with TITM4C chip as the core of the data process module,data acquisition module,data communication module,data storage module and electromagnetic isolation module;based on the model of on-line calculation of coal quality parameters and boiler efficiency completed with C++ and assembly language as a tool of software,including the measure model architecture and steam enthalpy query considered in both program memory consumption and computation speed.(4) Testing the monitoring instrument in a lab environment have been completed which the results show the stability of the performance meet the design requirements.