The working principle of the falling film evaporator is that the feed liquid is fed from the top of the heating chamber, distributed evenly into each heat exchange tube via the liquid distribution and film forming device, and flows down in a uniform film along the inner wall of the heat exchange tube.
During the downflow process, it is heated and vaporized by the shell-side heating medium, and the generated vapor and liquid phase enter the evaporator separation chamber together, and the vapor and liquid are completely separated, and the secondary vapor enters the condenser. The condensate turns into a liquid state, and the concentrated feed liquid is discharged from the outlet at the bottom of the separation chamber to complete the evaporation and concentration process.
Functional principle of the falling film evaporator
In falling film evaporation, speise liquid added from the upper tube box of the heating chamber of the falling film evaporator Through the liquid, the distribution and film-forming device is distributed evenly in each heat exchanger tube and flows from top to bottom in a uniform film form under the action of gravity, vacuum induction and air flow.
During the flow process, it is heated and vaporized by the shell-side heating medium, and the generated vapor and liquid phase enter the evaporator separation chamber together. The vapor and liquid are completely separated, and the vapor enters the condenser to condense (single-effect operation), or enters the next effect evaporator as a heating medium to realize multi-effect operation, and the liquid phase is discharged from the separation chamber.
Evaporation is a unitary process of concentrating a solution. In general, the solvent can be volatilized, but themost solutes have near-zero vapor pressure and cannot volatilize. The process of removing some of the solvent and concentrating the solution by evaporating it under boiling conditions is called evaporation.
In most cases, the evaporator uses water vapor as the heating medium (commonly called heating steam, primary steam or live steam) and transfers heat indirectly through the metal wall to the solution. After that, the solution is heated, the solvent boils and evaporates, and the vapor produced (in most cases also water vapor) is called secondary vapor.