Steam recycling system and method in polysilicon production

Abstract

The invention relates to the technical field of polysilicon production, in particular to steam recycling system in polysilicon production. The steam recycling system in polysilicon production comprises a superheated saturated steam source, wherein a temperature-decreased pressure reducer is connected with the superheated saturated steam source for desuperheating and decompressing superheated saturated steam so as to obtain medium-pressure saturated steam and \ or low-pressure saturated steam; a saturated steam utilization device is connected with the temperature-decreased pressure reducer forreceiving the medium-pressure saturated steam and \ or the low-pressure saturated steam and outputting low pressure steam and low pressure condensate after flashing; a steam condensate storage tank isconnected with a flash tank and a low-pressure saturated steam utilization device for receiving the low-pressure condensate; and a high temperature water pump and the steam condensate storage tank isconnected for conveying the condensate from the steam condensate storage tank to the temperature-decreased pressure reducer, and the condensate is mixed and cooled with the superheated saturated steam in the temperature-decreased pressure reducer so as to obtain the medium-pressure saturated steam and / or low-pressure saturated steam.

Description

technical field [0001] The invention relates to the technical field of polysilicon production, in particular to a steam recycling system and method in polysilicon production. Background technique [0002] In the polysilicon production process, there are many reaction equipment and heat exchangers in the cold hydrogenation and rectification workshop, such as: reboiler, silicon tetrachloride preheater, hydrogen heater and rectification tower, etc., which are required in the production process To heat up and cool down, a large amount of medium-pressure steam and low-pressure steam are consumed at the same time. In the process of heating with medium-pressure or low-pressure steam, a large amount of medium-pressure or low-pressure condensate is produced when the steam is cooled, and the medium-pressure condensate passes through the flash tank to flash part of the steam, and the remaining 100-150 degrees Generally, a large amount of condensate cannot be used directly, and further...

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Problems solved by technology

[0003] Since the condensate contains a lot of waste heat, direct discharge will cause waste of heat and water resources; moreover, the condensate contains very low calcium and magnesium plasma, which meets the process index requirements of desuperheating water

At present, the steam desuperheating and pressure reducing devices of various enterprises use 35 ℃ desalted water to cool down, and the cost is relatively high

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