Treatment of acid wastewater from coal-based ethylene glycol production*ao

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In the process of producing ethylene glycol from syngas, a liquid phase is formed in the process stream, containing *ao acid at a concentration of 0.5–5%. The low-concentration *ao acid present in this liquid phase not only causes severe corrosion to the production equipment but also makes subsequent environmental treatment more difficult. Dalian Rick Technology Co., Ltd. has successfully developed a catalytic reduction technique that converts the dilute *ao acid present in the process liquid phase into sub-*ao acid esters, which are then returned to the ethylene glycol system as raw materials. This approach not only reduces the consumption of nitrogen oxides and the amount of alkali needed for neutralizing the liquid phase, but it also addresses the issue of equipment corrosion, as well as helping to solve environmental problems. The *ao acid content in the liquid phase of the treated process fluid can be reduced to below 0.1%. The reaction principle is as follows: HNO3+2NO+3CH3OH = 3CH3ONO+2H2O