System with extraction condensing unit changed into back pressure unit on basis of spraying heat pump and operation method of system

Abstract

The invention provides a system with an extraction condensing unit changed into a back pressure unit on the basis of a spraying heat pump and an operation method of the system. The system is reasonable in structural design and efficient, and saves energy. The system comprises a high-pressure cylinder, a low-pressure cylinder, a boiler, an oxygen removing device, a water feeding pump, a high-pressure heater, a boiler water feeding pipeline, a main steam input pipeline, the spraying heat pump, a water supplementing heater, a cooling device, a control system, a first valve, a second valve, a third valve, a high-pressure heat supply steam pipeline, a low-pressure heat supply steam pipeline, a high-pressure drive steam pipeline, a water supplementing heater water input pipeline and a water supplementing heater water output pipeline. For heat users requiring high-pressure steam parameters, the spraying heat pump injects low-pressure heat supply steam with high-pressure drive steam, and the high-pressure heat supply steam pipeline supplies the high-pressure heat supply steam. When the requirement for temperature of the high-pressure heat supply steam needed by the heat users is not high,the water supplementing heater is additionally arranged in the high-pressure drive steam pipeline, and the boiler supplies water to cool and drive the high-pressure drive steam of the spraying heat pump.

Description

technical field [0001] The invention relates to a system for converting a condensate extraction unit into a back pressure unit based on a jet heat pump and an operation method thereof. Background technique [0002] In recent years, the electric power industry has become a key area of ​​energy saving and pollution reduction. Small and medium-sized condensing units have high coal consumption for power generation, which is not compatible with the energy-saving and emission-reduction requirements currently advocated by the country. The production cost is relatively high, and power generation losses affect corporate profits. Under the condition that the heating load condition permits, the back pressure transformation of the extraction condensing unit is carried out, and the heat discharged from the condensed steam of the extraction condensing turbine to the atmosphere through the cooling tower is eliminated, so as to avoid the loss of the cold source and fully realize the energy ...

AI Technical Summary

Problems solved by technology

[0004] In the conversion of condensing unit to back pressure unit, there are the following two situations: (1) Most of the heat users in the heating power station require low steam source pressure, while individual heat users require high steam source pressure. At this time, if Transform the extraction condensing unit into a back pressure unit with higher exhaust steam pressure. If the higher exhaust steam pressure is used to meet the needs of all heat users, and the lower pressure steam is obtained by throttling the temperature and pressure reducer 8, then the economical Great discount; at the same time, the exhaust pressure is too high, resulting in a large reduction in the power generation of the whole plant, which cannot meet the electricity demand of the self-provided power station

(2) The steam source pressure required by all heat users is low, but since the high-pressure cylinder is made of cast steel and the low-pressure cylinder is made of cast iron in the structure of small and medium-sized extraction condensing turbines, if the exhaust pressure of the modified steam turbine is required to be low, Due to the difficulty of opening the cylinder behind the cast iron, it is impossible to adopt the usual scheme of adding a heat-resistant baffle and opening an exhaust pipe in front of the plate. Only by lowering the exhaust pressure of the steam turbine can the exhaust temperature be lowered. If the safety temperature requirements of the rear cylinder material are met, the user’s steam requirements cannot be met at this time; if the hole is opened at the high-pressure cylinder, the exhaust steam pressure will be higher, and the steam parameters required by the user must be obtained through the desuperheater and pressurizer

Since the principle of temperature and pressure reducer 8 is the throttling effect, there is a large throttling loss, which greatly reduces the economy of the whole plant after the transformation; at the same time, the original low-pressure cylinder is not used (the part in the dotted line in the figure), resulting in The power generation has dropped a lot and cannot meet the power demand of the self-provided power station

Images