Case study of using a triple-effect evaporator to treat wastewater from an epoxy resin company.
Source: Date:May 21, 2026 Click:
Project Name: Wastewater Treatment Case Study of an Epoxy Resin Company
Evaporator Type: Triple-Effect Evaporator
Equipment Specifications: Processing Capacity 200t/d
Project Overview:
Water Quality Characteristics and Process Analysis:
Epoxy resin wastewater has a complex composition, mainly consisting of macromolecular intermediates generated from polymerization reactions and some inorganic salt ions. It contains high concentrations of sodium chloride and small amounts of sodium hydroxide, resulting in high chemical oxygen demand (COD) and significant treatment challenges. Pretreatment is required before it enters the evaporation system.
The wastewater contains COD, and after repeated concentration, the COD content gradually increases. When it accumulates to a certain level, the COD content exceeds the salt content, which will prevent the evaporation system from effectively desalinating, further increasing the concentration of the mother liquor. We designed a system where all mother liquor is discharged externally to control the COD content within the system, ensuring stable operation of the evaporation system. This project utilizes a triple-effect plate forced circulation evaporator tailored to the specific water quality conditions.
Process Flow Description:
The triple-effect evaporation system process:
The raw liquid first enters the pretreatment system to remove most of the COD before entering the preheating system for preheating.
After entering the preheating system, the mixed liquid and the fresh steam condensate from the first-effect heater are preheated. The preheated material, following a three-effect co-current process, first enters the first effect.
The material entering the first-effect evaporator system is circulated and heated in the heating chamber by a circulating pump, then evaporated and separated in the separator. The boiling vapor rises, while the concentrated liquid remains in the system. When the second effect needs feeding, the automatic control system automatically sends the concentrated liquid from the first effect to the second effect; when the third effect needs feeding, the automatic control system automatically sends the concentrated liquid from the second effect to the third effect. When the crystal slurry concentration in the third effect reaches the design value, it is discharged from the separator. The crystal slurry enters the thickener, then enters the centrifuge for separation, yielding solids, while the mother liquor is completely discharged.
Secondary Steam Flow:
First-Effect Heater Heat Source: External saturated fresh steam
Second-Effect Heater Heat Source: Secondary steam from the first effect
Third-Effect Heater Heat Source: Secondary steam from the second effect
The secondary steam generated by evaporation carries a small amount of liquid droplets. This contaminated secondary steam rises and enters the demister. Through countercurrent washing, the tiny liquid droplets entrained in the secondary steam are washed out and reintroduced into the feed liquid. The secondary steam, now free of mist, enters the steam side of the next effect heater.
The external saturated fresh steam, after heat exchange, condenses into water and goes to the preheater to preheat the raw materials.
The secondary steam from the third effect enters the condenser for condensation.
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