| With the development of economic, the demand for electricity is growing, along with the air pollution getting worse, So "Large-capacity, high-parameter, low-emission" boiler is the inevitable trend of development of electric power industry, and requirements of the State for pollution emission of thermal power plant are very strict. In order to meet environmental requirements, the boiler must be conducted low NOx combustion transformation. However, Low NOx combustion technology will have some influence on the boiler performance. The task of this article is the research on the issue of overtemperature on the superheater and reheater of the boiler caused by using Air-staged combustion technique.We can find from data taken from the scene DCS system and the calculation results of the wall temperature at superheater and reheater that outlet steam temperature of high temperature superheater and reheater is higher than the design parameters,even outlet steam temperature of some tubes have exceeded 20℃ than the design parameters. In order to cope with overtemperature of the wall temperature at superheater and reheater brought by low NOx combustion transformation, this paper presents three solutions, we can transform low temperature superheate in order that we can drop inlet steam temperature of superheater to solve this problem.This paper analyses the thermal performance of the boiler of present operating condition and solutions proposed by this paper, by comparing results of thermodynamic calculation, the specific program can be determined.On the basis of the thermodynamiccalculation, this paper calculate separately the wall temperature of the boiler under transformation of the former, present operating condition and rehabilitation program. By comparing the wall temperature of the boiler under three situations, this paper explore the feasibility of different rehabilitation programs to cope with the problem of overtemperature of the wall temperature at superheater and reheater. |
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