Stainless Steel DTB Crystallizer

The DTB crystallizer is a crystal slurry internal circulation crystallizer. Its typical features are that there are stirrers, guide tubes and baffles inside the crystallizer, as well as matching heat exchange devices and fine crystal elimination devices.

The crystal slurry liquid rises from the bottom of the inner guide tube through the built-in stirrer, and contacts with the area with higher supersaturation at the liquid surface to consume the supersaturation. It then descends along the annular local area between the inner guide tube and the outer guide tube. At the annular gap between the crystallizer cylinder and the outer guide tube, the crystal slurry liquid and the clarified liquid are separated, and the crystal slurry liquid continues to circulate downward. The clarified liquid enters the fine crystal elimination device from the outer annular gap to dissolve the excess fine crystal nuclei, which ensures that the crystal nuclei will not be excessive, making the particle size distribution of the crystals more uniform.

In the evaporation crystallization process, the rate of supersaturation generation depends on the evaporation rate, that is, the evaporation intensity of the equipment. The greater the evaporation intensity, the faster the supersaturation is generated, and the easier it is to form an excessively high supersaturation. The elimination of supersaturation mainly depends on the spontaneous nucleation and growth process of the crystal.

If there is enough crystal surface and a faster growth rate in the crystallizer, the supersaturation generated by evaporation can grow completely on the crystal surface, and the supersaturation of the solution will not exceed the larger supersaturation of the solution, so that the solute will not eliminate the supersaturation by nucleation process, and thus a large number of crystal nuclei will not be generated.

If there is insufficient crystal surface in the solution, the growth of the crystal is not enough to eliminate the supersaturation generated by evaporation, so that the supersaturation of the solution is too high and in an unstable area. The supersaturation of the solution will consume the supersaturation by spontaneous nucleation process, thus forming a large number of fine particles. Therefore, it is necessary to control the evaporation intensity during the evaporation crystallization process so that the supersaturation of the crystal system is always within the crystal metastable zone, so as to ensure that the designed evaporation crystallization equipment can produce products that meet the requirements of the design task.

The longer the crystal stays in the growth zone, the longer the crystal grows, and the larger the crystal size. The formation of large-size crystals requires sufficient growth time. Based on accurate crystallization kinetics data, we will design a suitable DTB crystallizer according to the crystal growth rate and the particle size required in the design task.

Based on the original DTB crystallizer, Kang Jinghui made a lot of improvements to the crystallizer to make it more in line with actual production conditions.

Operation method: continuous crystallization, intermittent crystallization

Crystallization method: water cooling crystallization, evaporation crystallization, freezing crystallization, vacuum crystallization

Name: Kelvin

Mobile/Whatapp No.: M/W:+86 18593449637

Email: kelvin@cnenco.com