Sulzer falling film process

More materials are purified by the Sulzer falling film processes (Sulzer Brothers, Inc. 1988), some of which are included in the following list ... 

According to Jancic (1989), the product lost in a sweating step is about 10%. The sweating times are also rather different with respect to the processes. Between 10 min in the dynamic Sulzer falling film process (see Jancic 1989) and 30 h in case of the static Hoechst process (see Rittner and Steiner 1985) are example sweating times for the purification of monochlorous acetic acid. 

The flowing melt improves the heat and mass transfer, reducing the boundary layer thickness and, therefore, the possibility of constitutional supercooling. Here, for instance, the Sulzer MWB process (falling film), nowadays called Sulzer falling film process (Figure 17.3), of Sulzer Chemtech Ltd needs to be mentioned. 

These above-mentioned dynamic operating mode plants have, besides pumps, no moving parts and produce the product in liquid form. The scale-up of the plants is quite easy, just by adding tubes or a new apparatus of tubes. AcryUc acid, benzoic acid, bisphenol A, and napthalene are few examples of materials which are purified with such a dynamic solid layer operating mode (Sulzer falling film process). 

The second group of the batch type of solid layer techniques are those with moving melts. Here again, three processes must be named the MWB-Sulzer, nowadays called Sulzer falling film (CH-PS 1967 U.S. 1985), the ICI-process (GB-PS 1964), and the BASF-process (DE-PS 1976), which is now distributed by the Kvaerner company. In all processes, the crystallization takes place on the inside of tubes, which are cooled from the outside. The melt coming from a feed tank is continuously circulated through the tubes until the crystal coat at the walls is thick enough, i.e., until... 

Commercial Equipment and Applications The falling-film crystallization process was invented by the MWB company in Switzerland. The process is now marketed by Sulzer Chemtech. Products successfully processed in the falling-film crystallizer are listed on Table 20-9. The falling-film crystallization process is available from the Chemtech Div. of Sulzer Canada Inc., 60 Worcester Rd., Rexdale, Ontario N9W 5X2 Canada. 

Sulzer A family of processes for purifying organic chemicals by melt-crystallization without using solvents. Two systems are in use static crystallization, and falling-film ciystalliza-tion. The latter is proprietary to Sulzer Chemtec, Switzerland. 

Falling film crystallization was developed by Sulzer Chemtech. Figure 2.3.5-7 shows a schematic of the process, which is characterized by three operating phases ... 

Figure 17.3 Flow diagram of a falling film crystallizer (Sulzer MWB process), (reproduced with permission from Sulzer Chemtech Ltd).

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