Coimbatore stands as one of South India's premier industrial, textile, and chemical processing powerhouses. With rapid industrial expansion comes an escalating regulatory focus on environmental compliance. Tamil Nadu Pollution Control Board (TNPCB) norms mandate stringent Zero Liquid Discharge (ZLD) systems across chemical, pharmaceutical, and textile dyeing sectors. For manufacturing units dealing with high-TDS effluents, RO rejects, and hazardous chemical sludges, conventional evaporators often fall short.
An Agitated Thin Film Dryer (ATFD) represents the pinnacle of thermal separation technology. By converting heavy, viscous slurries and pastes directly into free-flowing dry powder in a single continuous pass, ATFD systems provide the ultimate safeguard for regulatory compliance and resource recovery.
What is an Agitated Thin Film Dryer (ATFD)?
An Agitated Thin Film Dryer (frequently referred to as a wiped film dryer) is a specialized mechanical thermal evaporator designed to process extremely viscous liquids, concentrated slurries, and crystallizable solutions that would instantly foul conventional heat exchangers.
Unlike standard shell-and-tube or plate evaporators, an ATFD utilizes high-speed internal rotor blades. These blades mechanically sweep the incoming liquid against the heated inner walls of a vertical cylindrical vessel, creating an ultra-thin, highly turbulent film. This rapid wiping action prevents scaling, localized overheating, and fouling, ensuring exceptional heat transfer coefficients even as the product transitions from a liquid phase to a semi-solid paste and finally to a dry powder.
Core Working Principle of Our Industrial ATFD Systems
- Continuous Feed Injection: The concentrated effluent or slurry is introduced uniformly into the upper section of the vertical heating jacket zone.
- Mechanical Agitation & Wiping: Specially designed pendulum or rigid rotor blades spread the liquid into a turbulent, thin film against the inner surface of the thermal jacket.
- Rapid Evaporation & Phase Change: Heat (via steam, thermic fluid, or electricity) transfers instantly across the vessel wall. Volatiles flash off immediately as vapor, while the residual solids progressively thicken.
- Solid-Vapor Separation: The downward-moving concentrated solids dry into powder or flakes and discharge through the bottom air-lock valve. Simultaneously, the evaporated vapors pass through an integrated vapor-liquid separator (cyclone/entrainment separator) to capture fine droplets before entering the condenser.
Key Technical Specifications & Build Variants
Local engineering and fabrication excellence in Coimbatore allow for custom-tailored metallurgy and drive configurations to match specific process chemistries.
| Technical Parameter | Standard Industrial Specification Range |
|---|---|
| Evaporation / Drying Capacity | 50 kg/hr to over 1,500 kg/hr (Custom scalable modular builds) |
| Heat Transfer Area (MOC) | 0.5 m² to 30 m² |
| Materials of Construction | SS304, SS316, SS316L, Duplex Stainless Steel, Hastelloy cladding |
| Heating Medium | High-pressure Steam, Thermic Fluid (up to 300°C), or Electrical Heaters |
| Operating Pressure | Full vacuum (for heat-sensitive solvent stripping) up to atmospheric pressure |
| Rotor Drive & RPM | Variable Frequency Drive (VFD) controlled, heavy-duty planetary/helical gearbox |
| Discharge Mechanism | Bottom discharge valve coupled with dual-stage bagging or screw conveyors |
Industrial Applications Across Coimbatore & Tamil Nadu
- Textile Processing & Dyeing Clusters: Recovery of concentrated salts (Sodium Chloride / Sodium Sulphate) from RO reject streams in ZLD ETP plants across Tirupur and Coimbatore districts.
- Chemical & Specialty Synthesis: Drying of heat-sensitive pigments, resins, polymers, and agrochemical intermediates without thermal degradation.
- Pharmaceutical Bulk Drugs & APIs: Solvent stripping, concentration of mother liquors, and recovery of high-value organic solvents under deep vacuum.
- Electroplating & Metal Finishing: Safe concentration of heavy-metal-bearing effluents and hazardous sludge stabilization.
Why Source Your ATFD from Coimbatore Manufacturers?
Custom Metallurgy & Piloting: Local fabrication units can perform bench-scale feasibility trials to determine exact heat transfer rates and blade profiles for unique effluent chemistries.
Turnkey ZLD Integration: Seamless integration with existing Multiple Effect Evaporators (MEE), centrifuges, and automated PLC-SCADA control panels.
Rapid Spares & Maintenance Support: Immediate availability of mechanical seals, bearings, wiper blades, and skilled field technicians to minimize plant downtime.
 Systems in Coimbatore | Zero Liquid Discharge Solutions){kind=link}