Sub-control phase-change heat exchange system and method based on grading combination heat exchange

Abstract

The invention discloses a sub-control phase-change heat exchange system based on grading combination heat exchange. The sub-control phase-change heat exchange system comprises a flue, an air channel, an air pre-heater, an external water pipeline, a steam supply valve of a low-temperature water heater, the low-temperature water heater, a water inlet valve of the low-temperature water heater, a steam-liquid heat exchanger, a steam supply valve of the steam-liquid heat exchanger, a steam supply valve of an air channel heat exchanger, an external steam supply valve of the air channel heat exchanger, a main water draining pipeline, the air channel heat exchanger, a water tank, a water pump, a water inlet valve of a flue heat exchanger, the flue heat exchanger, and a steam outlet valve of the flue heat exchanger. According to the sub-control phase-change heat exchange system, heat release exchangers which utilize the waste heat of recycled flue gas are arranged in a grading combination mode; according to different situations such as ambient air temperature, operating conditions and the like, the waste heat can be utilized to heat boiler supplied air, condensed water on the side of a steam turbine and the like in a combination mode; meanwhile, the temperature of the condensed water is improved through grading heating, higher energy quality is obtained, and the optimal economic benefit of recycling the waste heat is achieved.

Description

technical field [0001] The invention relates to the technical field of safe and controllable flue gas waste heat recovery, in particular to a separate control phase change heat system and a heat exchange method based on hierarchical combined heat exchange. Background technique [0002] In domestic and foreign enhanced heat transfer technologies and technologies dedicated to waste heat recovery and utilization, many high-efficiency phase-change heat transfer technologies have been developed by utilizing the characteristics of high heat transfer coefficient and uniform temperature of vapor condensation and liquid boiling evaporation. Separately controlled phase change technology divides the traditional unified phase change heat process into independent units and different processes, and controls the phase change parameters of different units separately according to needs, which has both strong flexibility and strong comprehensive ability. As a result, the adaptability and econ...

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Problems solved by technology

Later patents (see the Chinese patent application with application number 201110322725.9) have improved on this, by entering the vapor-liquid heat exchanger with a high-parameter external steam source to assist in heating the condensate, but due to the high-parameter external steam source and low parameter After the steam is mixed in the vapor-liquid heat exchanger, the temperature decreases, so that the heat exchange temperature difference with the condensate decreases, thereby increasing the heat exchange area of ​​the heat exchanger

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