MULTI-STAGE FLASH EVAPORATION ACID RECYCLING SYSTEM

Abstract

The present invention relates to a system for acid recovery via multistage flash evaporation, including a preheating unit, a high-pressure reaction kettle, a flash evaporation unit, and a gas-liquid separator. The preheating unit comprises at least one preheating tower connected to a first feed port of the high-pressure reaction kettle for preheating the slurry. The flash evaporation unit includes at least one flash evaporation tank connected to a first discharge port of the high-pressure reaction kettle for flash evaporation of the post-reaction slurry. The vapor outlet of the flash evaporation tank is connected via a steam pipe to a heat exchanger of the preheating tower. A gas-liquid separator is installed on the steam pipe to separate the sulfuric acid droplets from the vapor.Compared with existing technology, the multi-stage flash evaporation acid recovery system provided by the present invention has a gas-liquid separator on the steam pipe of the flash evaporation tank, which separates and recovers sulfuric acid from the steam. This design only requires the pipe in front of the gas-liquid separator to be treated for corrosion resistance, thereby avoiding scale formation in the preheating tower, reducing pipe corrosion treatment costs, and minimizing sulfuric acid waste.

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