The working principle and characteristics of quality OSLO evaporation crystallizer
The quality OSLO evaporation crystallizer is a fluidized bed crystallizer with particle size classification. Its typical feature is that the supersaturated feed liquid rushes through the bottom of the downcomer in the middle of the crystallizer, and then turns to rise. Nuclei are grown and supersaturation is eliminated. The quality OSLO evaporation crystallizer is capable of producing crystals with larger particle sizes.
In the process of quality OSLO evaporation crystallizer, the generation rate of supersaturation depends on the evaporation rate, that is, the evaporation intensity of the equipment. The greater the evaporation intensity is, the faster the supersaturation is generated, and the easier it is to form too high supersaturation. The elimination of supersaturation mainly depends on the spontaneous nucleation of crystals and the growth process of crystals. If the crystallizer has sufficient crystal surface and a fast growth rate, the supersaturation caused by evaporation can all grow on the crystal surface, and the supersaturation of the solution will not exceed the larger supersaturation of the solution. The supersaturation is eliminated by the nucleation process of the solute, so that a large number of nuclei will not be generated.
If the crystal surface in the solution is insufficient, the growth of the crystal is not enough to eliminate the supersaturation caused by evaporation, so that the supersaturation of the solution is too high, and in the unstable region, the supersaturation of the solution will be consumed by the spontaneous nucleation process. supersaturation, resulting in the formation of a large number of fine particles. Therefore, it is necessary to control the evaporation intensity of the quality OSLO evaporation crystallizer in the process of evaporation and crystallization, so that the supersaturation of the crystallization system is always within the crystallization metastable region, so as to ensure that the designed evaporation and crystallization equipment can produce products that meet the requirements of the design task. .
The longer the residence time of the crystal in the growth zone, the longer the crystal growth time and the larger the crystal size. The formation of large grain size crystals requires sufficient growth time. We will design a suitable quality OSLO evaporation crystallizer based on accurate crystallization kinetic data, according to the crystal growth rate and particle size required in the design task.