Start calculation method and system for supercritical boiler

Abstract

The invention discloses a start calculation method and system for a supercritical boiler. According to the method, first, furnace combustion calculation is performed, wherein a furnace is divided into two parts, namely a radiation heat exchange area and a radiation convection area, and calculation is performed on the two parts respectively to obtain furnace outlet smoke temperature, furnace heat absorption percentage and smoke specific heat under different combustion rates; and second, boiler heating surface heat exchange calculation is performed, wherein on the basis of analyzing and simplifying flowing heat transfer characteristics of an in-pipe working medium side and an out-pipe smoke side in a heating surface in the boiler starting process, a distributed parameter model considering changes of thermal parameters along with position coordinate changes is adopted, mathematic models of change laws of working medium temperature, pressure, enthalpy values, heating surface metal temperature and smoke temperature in the starting process are established according to a mass conservation equation, a momentum conservation equation, an energy conservation equation, a metal heat reservation equation and a complementary equation, and solving is performed. Through the start calculation method and system, arrangement forms of different boiler starting systems can be calculated and compared, and an optimal boiler starting system can be provided for a user.

Description

technical field [0001] The invention belongs to the field of boiler start-up, and in particular relates to a start-up calculation method and system for a supercritical boiler. Background technique [0002] Boiler start-up system and steam turbine bypass system are installed on the supercritical unit, which can greatly improve the flexibility and economic benefits of the supercritical unit. How to design the best boiler start-up system according to the user's investment situation and power plant operation mode, so as to minimize the heat loss during start-up; The temperature of metal walls such as heaters is within the allowable range. While satisfying the above conditions, the operator also needs to know the matching relationship between the boost curve and the combustion rate curve so that the boiler can boost the pressure according to the predetermined boost curve. The basis for solving the above problems is to research and develop calculation methods that can accurately...

AI Technical Summary

Problems solved by technology

Most of the existing calculation methods are only suitable for the calculation of the dynamic characteristics of the boiler when there is a small change near the steady-state operating point, and the error is large when used for the calculation of the start-up process

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