Vapor-liquid separators Falling film evaporators

Figure 1 Flowsheet of the RCH/RP hydroformylation process 38 1 Continuous flow stirred tank reactor,424 2 Phase separator, 3 Stripping column, 4 Distillation column, 5 Heat exchanger, 6 Falling film evaporator, 7 Liquid vapor separator.

Fig. 4. Flow diagram of the Ruhrchemie/Rhone-Poulenc process (137) 1, continuous-flow, stirred tank reactor 2, phase separator 3, stripping column 4, distillation column 5, heat exchanger 6, falling film evaporator 7, liquid-vapor separator.

The head vapor was liquefied in a condenser cooled by a chilled glycol solution. The condensate, forming two liquid phases as expected, was collected in a static decanter separating a light phase rich in hexane and a heavy phase rich in water and alcohols. A vacuum pump connected to the condenser maintained the system under a reduced pressure in the order of 200 torr to lower all temperatures to the end of reducing polymerization in the falling film evaporator. 

Falling-Jilm-type evaporator. A variation of the long-tube type is the falling-film evaporator, wherein the liquid is fed to the top of the tubes and flows down the walls as a thin film. Vapor-liquid separation usually takes place at the bottom. This type is widely used for concentrating heat-sensitive materials such as orange juice and other fruit juices, because the holdup time is very small (5 to 10 s or more) and the heat-transfer coefficients are high... 

---