I. Introduction
Separation technology is one of three major chemical production technologies. The separation process has a great impact on product quality, efficiency, consumption and benefit. The TFE Mechanically-agitated Short Path Distillation Machine is a device used to perform separation through the volatility of the materials. This device has a high heat transfer coefficient, low evaporation temperature, short material residence time, high thermal efficiency and high evaporation intensity. It is widely used in the industries of petrochemicals, fine chemicals, agricultural chemicals, food, medicine and biochemical engineering, to conduct the processes of evaporation, concentration, solvent removal, purification, steam stripping, degassing, deodorization, etc.
The Short Path Distillation is a new and efficient evaporator that can carry out falling film evaporation under vacuum conditions, in which the film is forcibly made by the rotating film applicator and has a high flow speed, high heat transfer efficiency and short residence time (about 5-15 seconds). It also possesses a high heat transfer coefficient, high evaporation strength, short flow time and large operating flexibility, which is especially suitable for the concentration by evaporation, degassing, solvent removal, distillation and purification of heat-sensitive materials, high viscosity materials and easy crystal and particle-containing materials. It consists of one or more cylinders with jackets for heating and a film applicator rotating in the cylinder. The film applicator continuously scrapes the feed materials into a uniform liquid film on the heating surface and pushes them downward, during which components with low boiling points evaporate and their residues are discharged from the bottom of the evaporator.
II. Performance Characteristics
•Low vacuum pressure drop:
When the vaporized gas of the materials transfers from the heating surface to the external condenser, there exists a certain differential pressure. In a typical evaporator, such a pressure drop (Δp) is usually relatively high, sometimes to an unacceptable degree. In contrast, the Short Path Distillation Machine has a larger gas space, the pressure of which is almost equal to that in the condenser; therefore, there is a small pressure drop and the vacuum degree can be ≤1Pa.
• Low operating temperature:
Due to the above property, the evaporation process can be conducted at a high vacuum degree. Since the vacuum degree increases, the corresponding boiling point of materials decreases rapidly. Therefore, the operation can be conducted at a lower temperature and the thermal decomposition of the product is thus reduced.
• Short heating time:
Due to the unique structure of the Short Path Distillation Machine and the pumping action of the film applicator, the residence time of the materials in the evaporator is short; in addition, the rapid turbulence of the film in the heating evaporator makes the product unable to stay on the evaporator surface. Therefore, it is especially suitable for the evaporation of heat-sensitive materials.
• High evaporation intensity:
The reduction of the boiling point of materials increases the temperature difference of heated media; the function of the film applicator decreases the thickness of the liquid film in a turbulent state and reduces the thermal resistance. Meanwhile, the process suppresses the caking and fouling of materials on the heating surface and is accompanied by good heat exchange, thus increasing the overall heat transfer coefficient of the evaporator.
• Large operating flexibility:
Due to its unique properties, the scraper film evaporator is suitable for treating heat-sensitive materials which require smooth and steady evaporation and high-viscosity materials whose viscosity increases dramatically with the increase of concentration, as its evaporation process is smooth and steady.
It is also suitable for the evaporation and distillation of materials containing particles or in cases of crystallization, polymerization and fouling.
III. Application Areas
The scraper film evaporator has been widely used in heat exchange projects. It helps the heat exchange of heat-sensitive materials (short time) especially, and can distil complex products with its various functions.
The scraper film evaporator has been used for concentration by evaporation, solvent removal, steam-stripping, reaction, degassing, deodorization (de-aeration), etc. in the following areas, and has achieved good results:
Traditional Chinese medicine and Western medicine: antibiotics, sugar liquor, thunder godvine, astragalus and other herbs, methylimidazole, single nitrile amine and other intermediates;
Light industrial foods: juice, gravy, pigments, essences, fragrances, zymin, lactic acid, xylose, starch sugar, potassium sorbate, etc.
Oils and daily chemicals: lecithin, VE, cod liver oil, oleic acid, glycerol, fatty acids, waste lubricating oil, alkyl polyglycosides, alcohol ether sulfates, etc.
Synthetic resins: polyamide resins, epoxy resins, paraformaldehyde, PPS (polypropylene sebacate esters), PBT, formic acid allyl esters, etc.
Synthetic fibers: PTA, DMT, carbon fiber, polytetrahydrofuran, polyether polyols, etc.
Petrochemistry: TDI, MDI, trimethyl hydroquinone, trimethylolpropane, sodium hydroxide, etc.
Biological pesticides: acetochlor, metolachlor, chlorpyrifos, furan phenol, clomazone, insecticides, herbicides, miticides, etc.
Waste water: Inorganic salt wastewater.
Post time: Nov-17-2022
