A method and a system for separating and treating impurities from a hydrogen chloride liquid mixture

Abstract

The present invention relates to a method and a system for separating and treating impurities from a hydrogen chloride liquid mixture, and particularly relates to a method and a system for separating and treating impurities from a hydrogen chloride liquid mixture produced from the process for preparing isocyanate with phosgenation. Said method comprising the steps of: sending said hydrogen chloride liquid mixture into a gas-liquid separation column for separation to yield a liquid phase flow comprising impurities at the bottom of said gas-liquid separation column, and the impurities comprising ammonium chloride; making the liquid phase flow comprising impurities flow into a neutralization tank through a liquid phase flow pipeline from the bottom of the gas-liquid separation column, neutralizing the liquid phase flow comprising impurities with an alkaline liquid in the neutralization tank to yield a neutralized solution, and sending the neutralized solution into a waste liquid treatment device from said neutralization tank for treatment. The method and system provided by the invent ion solve the problem of the blocking of the liquid flow pipeline, the valve and the gas-liquid separation column due to impurity deposit ion, and reduce the shutdown frequency for maintenance.

Dependencies are inferred from the claim text.