Multi-working-medium backheating type Rankine cycle system

Abstract

The invention relates to a multi-working-medium backheating type Rankine cycle system. The multi-working-medium backheating type Rankine cycle system utilizes a turbine to pump steam to heat the air and boiler feed water (or including liquid and gas fuel), so that the identical effect of heating feed water by pumping steam and cycling backheating is achieved. A smoke-air short circuit is effectively avoided by omitting an air preheater in a tail flue. Exhaust temperature is effectively lowered and low-temperature corrosion of smoke is avoided during heat transfer intensifying by arranging the air preheater outside a boiler and arranging a feed water overheater, a feed water heater and a phase change heat exchanger.

Description

technical field [0001] The invention relates to a multi-working medium heat-regenerating Rankine cycle system, and specifically belongs to the technical field of steam extraction and heat-regenerating cycle of a steam power plant in a thermal power plant. Background technique [0002] A thermal power plant that uses water vapor as a working medium is a large-scale factory that converts thermal energy into mechanical energy, and then converts mechanical energy into electrical energy. The cycle applied in power plants is very complicated, but in essence, it is mainly completed by the Rankine cycle composed of boilers, steam turbines, condensers, water pumps and other equipment. The working principle is: the feed water is first pressurized by the feed water pump and then sent Into the boiler, the water in the boiler is heated and vaporized to form high-temperature and high-pressure superheated steam. The superheated steam expands and does work in the steam turbine and becomes l...

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Problems solved by technology

[0010] 2. Due to the large heat exchange area and volume of the air preheater, such as the rotary air preheater, etc., it is prone to wear and low temperature corrosion, resulting in air leakage and air short circuit, thereby increasing the work of the boiler blower and induced draft fan. consumption;

[0011] 3. Because the air preheater has a large volume and must be arranged in the flue, the air and flue gas ducts are long, the equipment (such as blower, air preheater) is difficult to arrange, and the project investment is high;

[0012] 4. Due to the limitation of feedwater temperature and extraction steam flow rate, it is necessary to reasonably distribute the heating degrees of feedwater recuperation heaters at all levels to reduce the irreversibility of the temperature difference between extraction steam and feedwater at all levels. Therefore, the design requirements for steam turbines are high. Facilitate the design of steam turbines using the optimal design method

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