Coking Wastewater Single-Effect Evaporator

Coking wastewater is a high-concentration organic wastewater generated during coking, coal gas purification, and chemical product recovery processes. It contains various toxic and harmful substances such as phenols, cyanides, ammonia nitrogen, and sulfides. Its complex composition and high treatment difficulty make it a key and challenging area in industrial wastewater treatment. Our single-effect evaporator for coking wastewater is specifically designed for the characteristics of coking wastewater, providing a complete solution from pretreatment to evaporation and crystallization, helping enterprises achieve zero wastewater discharge goals.

I. Challenges and Countermeasures in Coking Wastewater Treatment

Coking wastewater has the following characteristics: high pollutant concentration, complex composition, poor biodegradability, and high toxicity. Traditional biological treatment methods are difficult to meet discharge standards, while simple evaporation and concentration face problems such as severe scaling, strong corrosiveness, and high energy consumption. Our single-effect evaporators address these challenges through the following technical solutions:

1. Comprehensive Pretreatment System: A complete pretreatment system is provided to handle tar, suspended solids, and colloidal substances in coking wastewater. This includes oil removal, coagulation and sedimentation, and filtration to ensure the cleanliness of the feed entering the evaporator and reduce scaling and clogging.

2. Corrosion-Resistant Design: Coking wastewater contains highly corrosive substances such as sulfides and cyanides. Parts of the equipment that come into contact with the material are made of special corrosion-resistant alloys or titanium, ensuring long-term stable operation under harsh conditions.

3. Anti-Scale Technology: A forced circulation evaporation process is used, with high-flow-rate circulation preventing material deposition on the heat exchange tube walls. An online cleaning system is also included for periodic chemical cleaning to maintain heat exchange efficiency.

II. Technical Parameters and Performance

1. Evaporation Capacity: Customized according to customer needs, with single-unit processing capacities ranging from 1T/H to 20T/H.

2. Evaporation Temperature: Flexibly set according to wastewater composition, typically within the range of 80-120℃. 

3. Material Selection: Parts in contact with materials can be made of 316L stainless steel, titanium, or special alloys.

4. Automation Level: Fully automatic control, enabling unattended operation.

III. Process Flow 

After entering the evaporation system, coking wastewater first passes through a preheater where it exchanges heat with condensate to recover heat, and then enters the evaporator heating chamber. Under the action of heating steam, water evaporates, and pollutants gradually concentrate. The secondary steam generated by evaporation is condensed and reused as clean water. The concentrated liquid can be further processed or valuable substances recovered depending on its composition.

For coking wastewater containing high concentrations of inorganic salts, after evaporation and concentration, it can enter the crystallization system to separate and recover salts such as sodium sulfate and sodium chloride, achieving comprehensive resource utilization.

IV. Environmental and Economic Benefits

1. Zero Wastewater Discharge: All water is evaporated, condensed, and reused; there is no wastewater discharge.

2. Resource Recovery: Valuable salts and chemical raw materials are recovered.

3. Energy Saving and Consumption Reduction: Energy saving is 30-50% compared to traditional evaporation technology.

4. Compliant Discharge: Meets increasingly stringent environmental regulations.

After adopting our evaporation system, a large coking enterprise can treat 500,000 tons of coking wastewater annually, recover 450,000 tons of condensate, and recover 3,000 tons of salts such as sodium sulfate. This saves millions of yuan in hazardous waste disposal costs annually, demonstrating significant economic and environmental benefits.