Method for comprehensively utilizing heat energy of high-temperature water of reduction furnace and/or hydrogenation furnace

Abstract

The invention discloses a method for comprehensively utilizing heat energy of high-temperature water of a reduction furnace and / or a hydrogenation furnace, comprising the following steps of: respectively introducing high-temperature water backwater from the reduction furnace and / or the hydrogenation furnace to a #1 high-temperature water heat exchanger, a #2 high-temperature water heat exchanger and a high-temperature water cooler so that the high-temperature water backwater in the #1 high-temperature water heat exchanger and hot water backwater from a heat exchanger produced by polysilicon perform heat exchange; carrying out heat exchange on the high-temperature water backwater in the #2 high-temperature water heat exchanger and hot water backwater from a frozen water unit; carrying out heat exchange on the high-temperature water backwater and circulation cooling water supply on the high-temperature water cooler for adjusting the temperature of the high-temperature water backwater; and reducing the temperature of the high-temperature water backwater when the high-temperature water backwater carries out the heat exchange through the #1 high-temperature water heat exchanger, the #2 high-temperature water heat exchanger and the high-temperature water cooler for cooling the reduction furnace and / or the hydrogenation furnace. The method can avoid corrosion destroy on precious equipment due to leakage of the heat exchanger produced by the polysilicon, can reduce the temperature of the high-temperature water backwater, is beneficial to safe operation of the reduction furnace and / or the hydrogenation furnace and saves the energy.

Description

technical field [0001] The invention relates to a method for comprehensive utilization of high-temperature water and heat in a reduction furnace and / or a hydrogenation furnace in polysilicon production. Background technique [0002] The reduction furnace and / or hydrogenation furnace, the main equipment of the polysilicon project, is generally steel equipment, and the internal reaction temperature needs to be maintained at 1000-1300 °C. In order to protect the equipment from being damaged by high temperature, a large amount of temperature range of 90 ~200℃ high temperature water for cooling to protect the safe operation of the equipment. [0003] Foreign technologies have little consideration for the utilization of high-temperature water waste heat in reduction furnaces and / or hydrogenation furnaces, and basically use air coolers or circulating water for cooling. Such technical solutions lead to a lot of waste of heat energy, large investment, and high operating costs. . ...

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Problems solved by technology

[0003] Foreign technologies have little consideration for the utilization of high-temperature water waste heat in reduction furnaces and / or hydrogenation furnaces, and basically use air coolers or circulating water for cooling. Such technical solutions lead to a lot of waste of heat energy, large investment, and high operating costs.

[0004] Domestic engineering companies have mostly considered the utilization of high-temperature water waste heat in reduction furnaces and / or hydrogenation furnaces, but the waste heat utilization is to flash the hot water in the jacket of the reduction furnace and / or hydrogenation furnace into steam, and the steam is used for polysilicon In the production of heat exchangers (such as rectification reboilers, etc.), the condensed water generated after the steam passes through the heat exchanger is returned to the jacket of the reduction furnace and / or hydrogenation furnace for recycling, which will cause:

[0005] (1) If there is a slight leakage of the process medium chlorosilane in the heat exchanger produced by polycrystalline silicon, it will react with steam condensed water to form hydrochloric acid and silicon dioxide. Hydrochloric acid is highly corrosive and will cause damage to the reduction furnace and / or hydrogenation furnace of valuable equipment. Corrosion or even damage;

[0006] (2) Flash evaporation requires a certain temperature difference to generate a large amount of steam. If low-grade steam is produced by flash evaporation, the use of heat exchangers for polysilicon production is not convenient due to the low temperature and pressure of the steam;

[0007] (3) If high-grade steam is flashed, the temperature and pressure of the high-temperature water return must be increased, which will increase the temperature of the inner wall of the reduction furnace and / or hydrogenation furnace, which is closer to the material of the reduction furnace and / or hydrogenation furnace—stainless steel Extreme service temperature, which will reduce the service life of stainless steel, therefore, have an impact on the safe operation of reduction furnace and / or hydrogenation furnace

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