The scraper film evaporator is a new type of high-efficiency evaporator that uses a rotating scraper to force film formation and high-speed flow, with high heat transfer efficiency and short residence time (about 10-50 seconds), and can perform falling film evaporation under vacuum conditions.
It consists of one or more cylindrical bodies with jacket heating and a simply rotating scraper. The scraper continuously scrapes the feed onto a uniformly thick liquid film on the heating surface and moves it downwards; During this process, low boiling components are evaporated, while the residue is discharged from the bottom of the evaporator.
Working principle of scraper film evaporator:
The material enters the evaporator radially from above the heating zone; The material is distributed to the heating wall of the evaporator through the fabric dispenser, and then the rotating scraper continuously and uniformly scrapes the material onto the heating surface to form a thin and uniform liquid film, which is pushed downwards in a spiral shape. During this process, the rotating scraper ensures continuous and uniform liquid film to generate high-speed turbulence, and prevents the liquid film from coking and scaling on the heating surface, thereby improving the heat transfer coefficient. Light components are evaporated to form a steam stream Ascend and reach the external condenser directly connected to the evaporator through the vapor-liquid separator; The heavy components are discharged from the cone at the bottom of the evaporator.
A special distributor can not only throw materials evenly to the inner wall of the evaporator to prevent materials from splashing into the evaporator and injecting steam flow, but also prevent materials just entering from flashing here, which is conducive to the elimination of foam. Materials can only evaporate along the heating surface.
A centrifugal separator designed based on material characteristics is installed at the upper part of the scraper evaporator to separate the liquid droplets in the rising steam flow and return them to the distributor.