An on-line estimation method for the expected value of upper end difference and lower end difference under all working conditions of heater

Abstract

The invention provides an on-line estimation method for target values of an all-condition upper end difference and lower end difference of a heater. The method comprises: step one, real-time data of a related measuring point at a given time are obtained; step two, calculation is carried out to obtain on-line estimation values of steam extraction quality flows of all heaters; step three, a heat transfer coefficient from a steam side to a heat exchange tube wall outside a heat exchange tube and a heat transfer coefficient of an aqueous phase working medium to the heat exchange tube wall inside the heat exchange tube are calculated, so that a theoretical maximum value of a total heat transfer coefficient of the heater is obtained when the dirtiness resistance of the heat exchange tube wall surface is zero; step four, a theoretical value of a dewatering outlet temperature of the heater is calculated, definition is carried out by a lower end difference and then a target value of the lower end difference of the heater is obtained; and step five, a theoretical value of an aqueous phase working medium outlet temperature of the heater is calculated, definition is carried out by an upper end difference, and thus a target value of the upper end difference of the heater is obtained. According to the invention, influences on the heat economy of the set by the upper end difference and the lower end difference of the heater can be analyzed; and a support condition is provided for real-time evaluation of heat economy of the heat regeneration steam-extraction system.

Description

technical field [0001] The invention relates to the technical field of thermal power plant operation optimization control, in particular to an online estimation method for the upper end difference and lower end difference of the heater under all working conditions. Background technique [0002] Various auxiliary equipment of thermal power plants play a very important role in the economy and reliability of power plant operation. The heater is one of the most important auxiliary equipment of the steam turbine. Using the steam recovery and steam extraction of the steam turbine to heat the condensed water and feed water can reduce the loss of cold source and improve the cycle heat efficiency of the unit. Therefore, the operating state of the heater has a great influence on the thermal economy of the whole unit. direct impact. During the operation of the unit, the difference between the upper end and the lower end of the heater is an important indicator for monitoring the operat...

AI Technical Summary

Problems solved by technology

In essence, the above-mentioned linear function relationship is only applicable to the estimation of the upper end difference and the lower end difference under the test working conditions, and whether the calculation error is large or small under the conditions other than the test working conditions becomes an uncontrollable factor

In addition, this method only involves the calculation of the upper and lower differences of the heater, and cannot be used to estimate the expected value of the upper and lower differences of the heater, and cannot analyze the influence of the upper and lower differences of the heater on the thermal economy of the unit. impact, and cannot provide support conditions for the real-time evaluation of the thermal economy of the regenerative steam extraction system

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