Method for measuring drainage pump output of low pressure heater system of thermal generator set based on energy balance

Abstract

The invention relates to a method for measuring the drainage pump flow of a regenerative system of a thermal generator set based on energy balance. A thermodynamic system in the method consists of low pressure heaters connected in series. The method comprises the following steps of: mixing drained water of a first-stage low pressure heater with outlet condensed water of the first-stage low pressure heater by using a drainage pump, wherein the drained water of the other low pressure heaters of all stages flows automatically stage by stage; acquiring the extraction temperature and pressure, the outlet water temperature and pressure and the drained water temperature of each low pressure heater from a database of a plant-level supervisory information system (SIS) or a decentralized control system (DCS) of a thermal power plant; calculating the stream extraction enthalpy value of each low pressure heater, the outlet water enthalpy value of the low pressure heater and the drain water enthalpy value of the low pressure heater; establishing a heat balance equation for each low pressure heater, and establishing a flow balance equation and a mixing point heat balance equation for a mixing point of outlet water of the drainage pump of the first-stage low pressure heater; deducing an iteration-free soft measurement model according to the balance equations, and calculating flow shares of the drainage pump; and finally, calculating the drainage pump flow according to a flow detection value of the condensed water.

Description

technical field [0001] The invention relates to an energy balance-based method for measuring and calculating the flow rate of a drain pump in a thermal power unit's low heating system, and belongs to the field of soft measurement. Background technique [0002] With the expansion of the capacity of thermal power units, the influence of the heat recovery system on the units has attracted more and more attention. In regenerative heaters, in order to improve the regenerative effect of surface heaters, low pressure heaters are usually equipped with a drain pump. The measurement of the flow rate of the drain pump has an important impact on the performance monitoring of the drain pump, the optimal operation of the drain pump, the analysis of the operating status of the heater group, and even the heat balance calculation of the heat recovery system. Therefore, it is necessary to monitor the flow of the drain pump online. At present, there are no reports on the calculation of the f...

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Problems solved by technology

It can be seen that using this calculation method not only needs to artificially preset the error threshold, but also needs to spend a certain amount of calculation time to obtain the result, so there are also certain disadvantages

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