Crystallizer MESSO

In comparison with existing crystallizers, including DTB, DP and Standard-Messo... 

Commercial suspension crystallizers are manufactured, among others, by Swenson and GEA Messo GmbH. Wirges [47] cites the following companies as suppliers of solution crystallization processes CT Umwelttechnik, HPD Evatherm AG, Chematur Ecoplanning Oy, Ebner CO KG, Balcke-Diirr GmbH, and Gea Kestner SAS. 

The Standard Messo multistage vacuum crystallizer Figure 8.52) provides a number of cooling stages in one vessel. The horizontal cylinder is divided into several compartments by vertical baffles that permit underflow of magma from one section to another but isolate the vapour spaces. Each vapour space is kept at its operating pressure by a thermocompressor, which discharges to a barometric condenser. 

Figure 8.52. Standard Messo multistage vacuum crystallizer...

Fig. 8.2-7 Continuously operated routing tube crystallizers with fine grain dissolving. Left) draft-tube-baffled (DTB) right) MESSO crystallizer...

Agitated tank crystallizer for continuous and discontinuous operation, crystallizer with forced suspension circulation, horizontal crystallizer and multistage, crystallizer with agitator and controlled flow (DTB), vortex crystallizer according to Standard-MESSO. 

Conical cooling crystallizer with settling zone according to Howard, vibrated crystallizer to prevent build-up of solid on the heating elements, fluidized-bed crystallizer system Krystal with cooling, evaporation or vacuum crystallization, DP-crystallizer system Escher-Wyss-Tsukishima, evaporation crystallizer with carrier gas by Robinson, vortex crystallizer Standard-MESSO. 

Table 7-7. Typical crystallizers using flash evaporation for solution supersaturation classified by supersaturation control, nucleation control and crystal bed control. Representation according to Mannesmann Engineering AG, Messo-Chemietechnik.

Forced-circulation crystallizer with control of solution supersaturation, crystal phase and nucleation (Messo crystallizer... 

The determination of the main dimensions of classifying crystallizers is briefly discussed in the following. For a comprehensive design method, see References [7.1, 7.39, 7.51]. In a classifying crystallizer, such as the Oslo and Messo crystallizer, a separation effect is caused by the different sedimentation behavior of different grain sizes in the upflowing solution. 

In the Messo turbulence crystallizer, a secondary circulation loop (see vortex) -driven by the primary circulation loop - is created in the outer suspension section. This secondary circulation loop serves the purpose of sorting out the coarser crystals from the inner draft tube recirculation process, concentrating them in an outer... 

A quadmple-effed evaporative crystallization is chosen as the adequate process (Figure 16.18). Whereas FC-type crystallizers are selected for the production of PDV salt with the desired average particle size of around 0.4 mm, a Messo Oslo-type crystallizer is chosen to produce the granular salt with the average particle size of... 

The Messo Oslo-type crystallizer reached runtimes of around 3 weeks between washouts without any disturbance from scaling. This was a breakthrough in the Oslo crystallizer history for salt crystallization and the approved consequence of the inversion of the internal recirculation. The process required about 11 t/h of heating steam and evaporated 34 t of water per houn... 

Figure 17.10 Principle process flow diagram of a suspension crystallization process without growth vessel, (reproduced with permission from GEA Messo PT).

Figure 9.4 Influence of nucleation on crystal size (GEA Messo).

---