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The global distillery and bio-ethanol industries are experiencing unprecedented growth, driven by the increasing demand for renewable energy sources and alcoholic beverages. However, this rapid expansion brings forth significant environmental and operational challenges, primarily centered around the management of spent wash—also known as stillage, vinasse, or distillery effluent. Spent wash is an extraordinarily complex, dark brown, highly viscous liquid byproduct characterized by an intensely high Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), and a heavy concentration of inorganic salts and organic matter.
Historically, the disposal of spent wash involved discharging it into nearby water bodies or utilizing it for fertigation. In 2024 and beyond, these primitive methods are completely obsolete. Environmental Protection Agencies worldwide have implemented stringent Zero Liquid Discharge (ZLD) norms. Discharging untreated stillage leads to severe aquatic toxicity, soil alkalization, and groundwater contamination. Consequently, modern distilleries are legally and ethically obligated to treat and recover by-products from their effluent. This regulatory pressure has transformed the management of spent wash from a mere waste disposal issue into a critical requirement for sustainable industrial operation.
Conventional wastewater treatment methods, such as anaerobic digestion alone or simple open-pond evaporation, are insufficient for modern production scales. They require massive land areas, emit foul odors, and fail to recover the valuable resources trapped within the effluent. Furthermore, traditional forced circulation evaporators often struggle with the severe scaling and fouling characteristics of spent wash, leading to frequent downtime, immense steam consumption, and unsustainable operational expenditures (OPEX). The industry desperately required a technological leap—which was realized through the advanced application of the Climbing Film Evaporator.
Compliance with strict global environmental regulations by completely eliminating liquid waste discharge through advanced evaporation.
Drastically reducing steam consumption and operational costs by integrating with MVR and TVR technologies.
Converting highly polluting waste into profitable commodities like DDGS animal feed and concentrated bio-fertilizers.
The Climbing Film Evaporator (also known as a rising film evaporator) represents the pinnacle of thermal separation technology for handling heat-sensitive, highly fouling, and foaming liquids like distillery spent wash. Its design and operational thermodynamics are specifically tailored to address the unique rheological properties of vinasse and stillage.
The core mechanism of a Climbing Evaporator relies on the principle of thermosiphon action. The spent wash is introduced at the bottom of long vertical tubes encased within a steam-heated shell. As the liquid absorbs heat, it begins to boil rapidly. The generated vapor expands violently, creating a high-velocity core that propels the remaining liquid upward along the inner walls of the tubes as a thin, highly turbulent film. This rapid upward movement ensures an exceptionally high heat transfer coefficient and an incredibly short residence time—often just a few seconds. For heat-sensitive distillery by-products, this means the organic compounds do not degrade, preserving their nutritional value for downstream applications like Distillers Dried Grains with Solubles (DDGS) production.
One of the most profound advantages of the Climbing Evaporator in this specific application is its inherent resistance to fouling. The high-velocity, turbulent flow of the liquid-vapor mixture creates a continuous scouring effect on the tube walls, significantly mitigating the deposition of calcium sulfate, silica, and organic scaling that plagues traditional evaporators. Furthermore, when integrated with Thermal Vapor Recompression (TVR) or Mechanical Vapor Recompression (MVR), the Climbing Evaporator achieves unparalleled thermal efficiency. By compressing and reusing the secondary vapor generated during the boiling process, distilleries can reduce their fresh steam consumption by up to 70%, radically transforming the economic viability of the ZLD process.
The utility of the Climbing Evaporator extends far beyond mere volume reduction; it is an integral component in the modern circular economy of the biochemical and fermentation industries.
In grain-based distilleries (such as corn or wheat ethanol plants), the thin stillage remaining after centrifugation contains valuable proteins, fats, and unfermented fibers. The Climbing Evaporator concentrates this thin stillage from approximately 5-8% total solids to a thick syrup of 30-40% total solids. This concentrated syrup is then blended back with the wet distiller's grains and sent to tube bundle dryers. The efficiency of the Climbing Evaporator directly dictates the energy consumption of the downstream drying process. By achieving higher concentration levels without fouling, the evaporator maximizes the yield and nutritional quality of the DDGS, which is sold globally as premium livestock feed.
Molasses-based distilleries face a unique challenge: their spent wash contains extremely high levels of potassium and ash, making it highly corrosive and prone to severe scaling. Climbing Evaporators designed for this scenario utilize advanced metallurgy (such as duplex stainless steel or titanium) and precise temperature gradients to concentrate the vinasse into a potash-rich syrup. This concentrated syrup can be co-fired in specialized incineration boilers to generate high-pressure steam and power, while the resulting ash serves as a high-grade potash fertilizer. This creates a self-sustaining energy loop within the plant.
Many distilleries first treat their spent wash in anaerobic digesters to generate biogas (methane) for boiler fuel. However, the resulting biomethanated effluent (BME) still requires concentration to achieve ZLD. The Climbing Evaporator efficiently processes this BME, separating it into a clean condensate (which is recycled back to the fermentation process or cooling towers) and a concentrated sludge that is dried and utilized as organic fertilizer. This multi-stage approach ensures zero waste and maximum resource recovery.
As the distillery industry moves towards Industry 4.0, the evolution of Climbing Evaporators is heavily influenced by digitalization, automation, and advanced materials science.
The future of spent wash evaporation lies in smart, autonomous systems. Modern Climbing Evaporators are being equipped with IoT sensors that continuously monitor feed flow rates, viscosity, temperature differentials, and condensate quality. Artificial Intelligence (AI) algorithms process this real-time data to create digital twins of the evaporation plant. The AI can predict fouling rates, automatically adjust the MVR compressor speed, optimize the feed distribution, and schedule predictive maintenance before a catastrophic scaling event occurs. This AI-driven technology ensures the evaporator operates at its peak thermodynamic efficiency 24/7, minimizing human error and downtime.
We are witnessing a shift towards hybrid evaporation systems that combine the high heat transfer of Climbing Films with the high-concentration capabilities of Forced Circulation or Agitated Thin Film Evaporators (ATFE) for the final finishing stages. This modular approach allows distilleries to push the concentration of spent wash beyond 60% total solids, facilitating easier drying or incineration. Furthermore, advancements in compressor technology are making MVR-driven Climbing Evaporators more robust, capable of handling higher boiling point elevations, and further driving down the carbon footprint of the distillery by-product recovery process.
(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. 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.
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).
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.
While meeting domestic market demand, the company's DDGS alcohol equipment and tube bundle dryer series products have been exported to Russia and Southeast Asian markets. We are capable of providing professional technical support and after-sales service nationwide for our vast user base.
In March 2002, the company took the lead in obtaining ISO9001:2015 international quality system certification (Certificate No.: 45021), establishing a complete quality assurance system aligned with international standards. In July 2007, it became a Jiangsu Provincial High-Tech Enterprise. In April 2009, the company obtained the Special Equipment Manufacturing License of the People's Republic of China (License No.: TS2232C42). In August 2012, it acquired the ASME "U" Stamp authorization, marking the company's entry into a new phase of development. The company possesses strong R&D capabilities and advanced manufacturing processes, currently employing over 3 senior engineers and more than 20 engineers and assistant engineers. Multiple innovative technologies have been patented, and many products hold leading positions domestically.
The company currently holds an absolutely leading position in evaporation technology and has extensive cooperation with many renowned large domestic group companies, including Zhuofeng Biology, Meihua Group, Yufeng Group, Yihai Kerry, North China Pharmaceutical Group, Harbin Pharmaceutical Group, Shouguang Juneng, Qilu Pharmaceutical, Qiyuan Pharmaceutical, Xiwang Group, Shengtai Biology, Zhejiang Huakang, Kelun Pharmaceutical (Yili), and Shandong Tianli.
We warmly welcome friends from various industries, both domestic and international, to visit us for cooperation and mutual development!
