Selection of thin-film evaporators

These all belong to membrane evaporators, while the thin-film evaporator you mentioned should refer to a scraper-type evaporator. Principle of the scraper-type evaporator: The scraper-type thin-film evaporator uses indirect steam heating, and is particularly suitable for drying materials with high water content that are viscous in nature. Various types of scrapers (centrally moving scrapers, hinged moving scrapers, roller-driven scrapers, and fixed rigid scrapers) help to form a uniform thin film on the heated cylinder wall; this film is then rapidly vaporized, with the water being removed from the top. Principle of falling film evaporator: The material is evenly distributed into each evaporator tube via a distributor. Under the action of gravity and the secondary steam generated by self-evaporation, the material forms a spiral-shaped film that flows from top to bottom; simultaneously, heat exchange occurs between this film of material and the steam on the outer wall of the tubes, causing the water in the material to evaporate. A stable temperature difference and heat transfer area ensure a consistent rate of water evaporation. Its characteristic is that the evaporator’s distribution disk is spiral-shaped, enabling particularly even distribution of the material, with the liquid flowing in a film form along the inner wall of the tubes. Principle of the rising film evaporator: The feed liquid is introduced at the bottom of the evaporator; once it enters the heating tubes, it rapidly boils and vaporizes, with the resulting secondary steam rising at high speed. The liquid mixture is driven by the rising steam, rising rapidly along the tube wall in a film-like manner, and continues to evaporate during this process. After entering the separator and undergoing secondary steam separation, the concentrated product is discharged from the bottom of the separation chamber; if the concentration does not meet the requirements, it is recycled for further concentration.

What was said upstairs is quite right; I’d like to recommend a manufacturer – Shijiazhuang Gongda Chemical Equipment Co., Ltd. They have been producing evaporators for many years and possess strong technical capabilities

If the material is corrosive, it is recommended to use a graphite falling-film evaporator.

I know a bit more about scraper-type thin-film evaporators. I think they are suitable for handling materials with high viscosity, but it’s difficult to deal with the residual material; it needs to be in a fluid state so that it can flow. If the viscosity is very high, approaching that of asphalt, it’s also hard to handle, as the residual liquid ends up in the distillation flask.

Could you recommend some manufacturers of thin-film evaporators upstairs?

Shijiazhuang Gongda Chemical Equipment Manufacturing Co., Ltd. has many years of extensive experience in evaporation design, and its work is of high quality For detailed information, please contact me: QQ351191859

There are many such devices available online; you can check them out. One issue is that a high level of vacuum is required – otherwise, there will be plenty of residues left, and the cleaning won’t be thorough

Wuxi Limaa Chemical Machinery Co., Ltd. mainly produces scraper-type thin-film evaporators, rising-film evaporators, and falling-film evaporators. It is currently the domestic manufacturer that offers the largest models of scraper-type thin-film evaporators (40 square meters)

This device is also used in PTA, but the domestic versions seem to not work very well; imported ones are better.

Scraper film evaporators come in two types: floating scrapers and fixed scrapers; they operate by forced film formation and are suitable for processing solutions with high viscosity. Film evaporators are suitable for producing materials with low viscosity, as the evaporation gas velocity is high. The rising film evaporators designed and manufactured by Hebei Nuoda Chemical Equipment Co., Ltd. have achieved good results in evaporating propylene solutions. We also produce film-evaporators; for inquiries, please contact: QQ: 490812555