All-backheating drainage system of heat supply network heater for supercritical concurrent boiler thermal power plant

Abstract

The invention relates to an all-backheating drainage system of a heat supply network heater for a supercritical concurrent boiler thermal power plant. Condensed water in a condenser passes through a shaft seal cooler of a condensed water system and then enters into a condensed water precision processing device; a drainage water cooling section is arranged in the heat supply network heater, and drainage water in the heat supply network heater is cooled by the drainage water cooling section; the cooled drainage water is boosted by a drainage pump, then passes through a drainage water cooler and exchanges the heat with condensed water from the condensed water precision processing device in the drainage water cooler; the heat-exchanged drainage water and the condensed water from the shaft seal cooler of the condensed water system are mixed to enter the condensed water precision processing device; and the condensed water from the condensed water precision processing device returns to the system after heat exchange, therefore, the desalting of more than 80 percent of a unit steam-water system through a chemical processing system is ensured, the boiler feedwater quality is ensured, and the long-term safety operation of a supercritical concurrent boiler and the heat exchange between the drainage water of the heat supply network heater and the heat supply network are also ensured; and compared with schemes of partially recovering the heat and then discharging the heat to the condenser, the invention improves the efficiency by a larger extent.

Description

technical field [0001] The invention relates to a supercritical (direct-current boiler) heat network heater drainage system for a steam turbine generator set in a thermal power plant. The influence of entering the condenser on the efficiency of the unit maintains that the efficiency of the unit does not decrease basically. Background technique [0002] At present, the heating and heating units are mainly subcritical and below parameters, and the 300MW class extraction and condensing units are the most assembled units. Now the parameters of the steam turbine generator units are gradually increasing, and the supercritical heating units are gradually entering the power system. [0003] At present, domestic units of 300MW and above are generally equipped with condensate polishing equipment to perform deep desalination of condensate to ensure the quality of condensate. The boiler evaporation capacity of the 300MW heating and heating unit is about 1000t / h, the steam extraction ca...

AI Technical Summary

Problems solved by technology

As a supercritical heating unit, if it still adopts the subcritical unit mode, the heat network heater drains water and directly enters the deaerator, less than 20% of the steam water system circulation of the unit will pass through the condensate polishing system, and more than 80% of the working fluid steam water will not pass through. Chemical water desalination is difficult to ensure the quality of boiler feed water, which will have a serious impact on the safety of the boiler and should be strictly prohibited

However, this method still has a certain amount of heat loss due to the drainage of the heating network heater, and there is a large efficiency difference between the system efficiency and the direct return of the drainage to the deaerator.

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