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The electroplating and metal finishing industries are vital cornerstones of modern manufacturing, providing corrosion resistance, aesthetic appeal, and enhanced electrical conductivity to components in automotive, aerospace, electronics, and heavy machinery sectors. However, these processes generate vast quantities of highly toxic rinse water. Containing complex mixtures of heavy metals (such as chromium, nickel, copper, zinc, and cadmium), cyanides, acids, alkalis, and organic brighteners, this effluent poses severe environmental and public health risks if left untreated.
Historically, facilities relied on chemical precipitation to remove metals, followed by discharging the treated supernatant into municipal sewers or surface waters. Today, this approach is no longer commercially or regulatory viable. Environmental protection agencies worldwide have instituted stringent regulations, pushing the industry toward Zero Liquid Discharge (ZLD). Consequently, the commercial demand for robust, energy-efficient thermal separation technologies has surged, positioning the Multi Effect Forced Circulation Evaporator as the definitive standard for industrial rinse water reclamation.
By maintaining high hydrostatic pressure within the heat exchanger tubes, boiling is suppressed until the liquor enters the vapor separator vessel. This design prevents localized concentration gradients and subsequent scaling inside the tubes.
An integrated axial flow pump drives the rinse water through the heat exchange tubes at velocities ranging from 1.5 to 3.5 meters per second. This high shear force continuously sweeps the tube walls clean, mitigating fouling.
By arranging multiple evaporation stages (effects) in series, the vapor generated in one stage acts as the heating medium for the next. This configuration drastically reduces raw steam consumption, lowering operational costs.
In chrome plating lines, rinse water carries away valuable chromic acid. A Multi-Effect Forced Circulation Evaporator concentrates this rinse water back to the original bath concentration, allowing direct recycling of the chromate solution into the plating tank. Simultaneously, it yields high-purity distillate water, which is routed back to the rinsing stations, closing the loop. The same principle applies to nickel plating, where nickel sulfate and nickel chloride are concentrated and reclaimed, saving thousands of dollars in raw chemical costs annually.
Metal finishing frequently requires acid pickling (using hydrochloric, sulfuric, or nitric acids) to remove oxides and scale from metal surfaces. The spent pickling liquor is highly corrosive and loaded with dissolved metal salts. Utilizing corrosion-resistant materials of construction, such as Titanium, Hastelloy, or Duplex Stainless Steel, our forced circulation evaporators safely concentrate these acidic streams. This enables the separation of clean acid for reuse and concentrates the metal salts into a crystallizable slurry, minimizing disposal volumes.
For facilities operating multiple plating lines (copper, zinc, tin, etc.), segregating waste streams can be logistically complex. The mixed rinse water is collected, neutralized, and routed to the Multi-Effect Forced Circulation Evaporator. The system concentrates the mixed salts to their saturation limit. The slurry is then discharged to a centrifuge or filter press, yielding dry salt cake for safe disposal or metal smelting reclamation, while returning 98%+ of the wastewater as pure boiler-feed quality water.
To achieve the lowest possible energy consumption, forced circulation evaporators are frequently paired with Mechanical Vapor Recompression (MVR) or Thermal Vapor Recompression (TVR). MVR compresses the waste vapor, raising its temperature and pressure so it can be reused as the heating source for the same evaporator. This setup bypasses the need for continuous boiler steam, making it the most energy-efficient thermal separation technology available for large-scale metal finishing plants.
Jiangsu Zongheng Concentration & Drying Equipment Co., Ltd. (formerly Yixing Yangxi Light Industry Machinery Factory), founded in 1992, is located in Zhoutie Town, Yixing City, on the shores of the beautiful Taihu Lake. The company covers an area of over 54,000 square meters, with a production workshop area of over 22,000 square meters.
Jiangsu Zongheng is a modern high-tech enterprise specializing in the manufacturing of concentration, drying, starch industry, alcohol DDGS, and Category III medium & low-pressure vessel equipment. It is currently a member enterprise of the China Starch and Alcohol Association. Its products are widely used in industries such as food fermentation, alcohol, chemical, pharmaceutical, environmental protection, and petrochemical.
The company's other main products include Tube Bundle Dryers, with design and manufacturing capabilities reaching 1600m² (making it a primary manufacturer of large tube bundle dryers). Other main products such as Single Screw Fiber & Germ Dehydrators and Wash Cyclones are recognized as high-quality products by starch manufacturers and the industry. High-quality products and a sincere service attitude have won consistent praise and trust from numerous users at home and abroad, fully demonstrating the company's first-class technical advantages and manufacturing capabilities for large-scale equipment.
Jiangsu Zongheng is always committed to exploration and innovation. Through years of sincere effort and user support, it has achieved sustained development. Main products include evaporation plants, comprising Multi-Effect Evaporators, Thermal Vapor Recompressors (TVR), Waste Heat Evaporators, and Mechanical Vapor Recompressors (MVR, achieving minimal unit energy consumption). These are widely used for liquid concentration, including distillates, alcohol stillage, ammonium sulfate, corn steep liquor, itaconic acid, threonine, starch sugar, sorbitol, glucose, fructose, trehalose, erythritol, organic wastewater, high-salinity wastewater, etc., making the company one of the domestic manufacturers with the most extensive product variety.
Modern metal finishing plants are integrating AI-driven monitoring systems. By monitoring temperature drops, flow rates, and pressure differentials across heat exchanger tubes, algorithms can predict scale formation and optimize Clean-in-Place (CIP) cycles, minimizing downtime.
As electroplating chemistries become more complex, evaporators must handle highly acidic and halide-rich environments. The industry is shifting toward exotic alloys like Super Duplex Stainless Steel, Titanium Gr. 2, and Hastelloy C276 to extend equipment lifespan to over 20 years.
To reduce capital and operational expenditure, hybrid systems combining membrane filtration (such as High-Pressure Reverse Osmosis or Electrodialysis Reversal) with thermal evaporation are gaining traction. Membranes pre-concentrate the rinse water, reducing the thermal load on the evaporator.
