Effluent and drain temperature measurement and calculation method of steam turbine surface-type heater

Abstract

The invention discloses an effluent and drain temperature measurement and calculation method of a steam turbine surface-type heater. The method comprises the following steps: a machine set rated power design condition or a performance test condition is selected as a reference condition; the thermal parameter of the j-grade heater under the reference condition is selected; the heat transfer characteristic coefficient of the pure condensation section of the heater under the reference condition is obtained by calculation according to a heat transfer equation of the pure condensation section; according to the heat transfer characteristic coefficient of the pure condensation section of the heater under the reference condition, the numerical experimentation, the model parameter identification algorithm based on a sample and the machine set power Pe under actual conditions, the heat transfer characteristic coefficient of the heater under the actual conditions is obtained; and finally, according to the heat transfer characteristic coefficient under the actual conditions, the effluent temperature under the actual conditions is calculated, wherein, the drain temperature under the actual conditions is equal to the saturation temperature corresponding to the side pressure of a heater case under the actual conditions.

Description

technical field [0001] The invention relates to a method for measuring and calculating the parameters of a surface heater of a steam turbine, in particular to a method for measuring and calculating the temperature of the outlet water and the water discharge of the surface heater of a steam turbine. Background technique [0002] With the continuous improvement of the parameters and capacity of thermal power units, improving the performance of the heat recovery system to improve the operating economy of the unit has attracted increasing attention. The measurement of the outlet water and drain temperature of the regenerative heater plays an important role in the calculation of the heat balance of the regenerative system and the monitoring and optimization of unit performance, so it is necessary to monitor it online. So far, there is no report on the method of measuring and calculating the outlet water and drain temperature of the surface heater in the heat recovery system. [...

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Problems solved by technology

[0003] At present, in the thermal power plant's plant-level monitoring information system SIS (Supervisory Information System) or system distributed control system DCS (Distribution Control System), although there are water outlet and drain temperature measurement points for the surface regenerative heater, but because of Poor measurement reliability is common due to poor operating conditions and weak maintenance. In addition, the conventional measurement method of water side temperature of the heater has the following shortcomings: First, thermal resistance type is often used in thermal power measurement system. Sensors are used to monitor the outlet water temperature of the regenerative heater, and the corresponding data acquisition system needs to use an active balance bridge to measure the resistance value of the sensor, which is expensive to measure; secondly, the thermal inertia of water temperature changes is large, and when the working conditions change greatly , the water temperature response shows a large thermal inertia, which affects the measurement accuracy; third, due to the complicated installation position on site, it is not easy to repair and maintain

The absence of any heater data will result in the inability to calculate the heat transfer coefficient, so the traditional heat transfer equation is suitable for design and verification calculations, and it is not convenient for the calculation and monitoring of outlet water and drain temperature during unit operation or test

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