Description
The thin film evaporator employs a distinct operational theory to facilitate efficient material processing. The process initiates as the material is introduced radially into the evaporator’s upper heating area. A specialized distributor uniformly directs the material onto the evaporator’s heating wall surface. Subsequently, a rotating film scraper continuously and evenly spreads the material, forming a consistently thin and uniform liquid film on the heating surface. This spiral motion propels the liquid film downward.
Throughout this process, the rotating film scraper plays a pivotal role by ensuring the continuous and uniform distribution of the liquid film. It induces high-speed turbulence, preventing the liquid film from adhering to the heating surface, thus mitigating the risk of coking and scaling. This action substantially enhances the overall transmission coefficient.
As the process unfolds, the lighter components within the material evaporate, giving rise to a vapor stream that ascends and proceeds through a vapor-liquid separator. This separator efficiently isolates liquid droplets from the vapor stream, directing them back to the distributor. This recycling mechanism not only prevents material splashing into the vapor stream but also aids in eliminating foam, ensuring that the material undergoes evaporation exclusively along the heating surface.
Furthermore, positioned in the upper section of the scraper film evaporator is a centrifugal separator, meticulously designed to align with the material’s characteristics. This separator effectively captures and separates liquid droplets carried within the rising vapor stream, redirecting them to the distributor for further processing.
Key Performance Features of the Thin Film Evaporator:
- Minimal Vacuum Pressure Drop:
- The scraper-type film evaporator exhibits an exceptionally small vacuum pressure drop. Unlike traditional evaporators with high pressure drops, this design provides nearly equal pressure throughout the system, achieving a vacuum degree as low as 5mmHg.
- Lower Operating Temperatures:
- The ability to maintain high vacuum conditions allows for lower operating temperatures. With increased vacuum levels, the boiling point of the material decreases significantly, reducing the risk of thermal decomposition during processing.
- Shortened Heating Duration:
- The unique structure of the scraper film evaporator ensures minimal material residence time. Additionally, high-speed turbulence within the heated evaporator prevents product stagnation on the evaporator’s surface. These characteristics make it ideal for heat-sensitive material evaporation.
- High Evaporation Efficiency:
- Lowered boiling points enhance the temperature gradient between the material and the heat medium. The film scraper’s function reduces liquid film thickness, inducing turbulent flow and reducing thermal resistance. Simultaneously, it prevents material scaling on the heating surface, ensuring efficient heat exchange and improved overall heat transfer coefficients.
- Operational Versatility:
- The scraper-type film evaporator’s unique performance characteristics make it suitable for a wide range of applications. It excels in processing heat-sensitive materials, handling high viscosity substances, and coping with varying viscosity concentrations. Furthermore, it effectively manages solid particle-containing materials, crystallization, polymerization, scaling, and similar challenging conditions during evaporation and distillation processes.
The scraper-type film evaporator finds widespread utility in heat exchange engineering, particularly for heat-sensitive materials where swift heat exchange is paramount. Its versatility extends to complex product distillation through various design configurations.
The scraper film evaporator has demonstrated its efficacy across multiple domains, yielding favorable outcomes in processes such as evaporation, concentration, desolvation, vapor extraction, chemical reactions, degassing, and deodorization (gas) for odor mitigation. Notable applications include:
- Pharmaceuticals and Medicine:
- Processing antibiotics, sugar solutions, and herbal medicines like Leigongteng and Huangqi, as well as intermediates like methylimidazole and mononitrile amine.
- Light Industry and Food Processing:
- Handling fruit juices, gravies, colors, flavors, spices, enzyme preparations, lactic acid, xylose, starch sugars, and potassium sorbate.
- Oil and Daily Chemical Industries:
- Evaporating lecithin esters, VE, cod liver oil, oleic acid, glycerol, fatty acids, waste lubricating oils, alkyl polyglucosides, alcohol ether sulfates, and more.
- Synthetic Resins and Fibers:
- Distilling polyamide resins, epoxy resins, paraformaldehyde, PPS (polypropylene sebacate), PBT, and propylene formate. Additionally, it serves in processing synthetic fibers like PTA, DMT, carbon fibers, and polytetrahydrofuran, among others.
- Petrochemicals:
- Suitable for handling TDI, MDI, trimethylhydroquinone, trimethylolpropane, sodium hydroxide, and other petrochemical compounds.
- Pesticides and Biotechnology:
- Applied in the evaporation of herbicides, insecticides, fungicides, and acaricides, including Ethofumesate, Prochloraz, Chlorpyrifos, Furazinol, Pendimethalin, and more.
- Wastewater Treatment:
- Effective in treating various wastewater types, including inorganic salt-laden wastewater.
The scraper-type film evaporator’s adaptability and versatility render it a crucial component in diverse industrial processes, ensuring efficient and precise outcomes across a spectrum of applications.
