结晶技术 溶液结晶器

溶液结晶

溶液结晶设备

溶液大量结晶。

Pimai NaCl

在大量结晶领域,GEA 的专业知识涵盖了进行溶液结晶的所有基本类型的结晶器,例如强制循环或套筒隔板式 (MSMPR) 结晶器、涡流 (DTB) 结晶器和流化床 (OSLO) 结晶器。因此,GEA 可以根据所需的产品结晶质量和大小,满足每位客户的特殊需求。GEA 供应上游和下游组件,例如预浓缩(多效、机械蒸汽再压缩、闪蒸和其他蒸发器配置)、去盐渍(增稠、过滤或离心)、干燥、固体物处理和包装。GEA 还可应客户要求,供应适合其设备、预制和模块化装置的管道、仪表和工艺控制系统。

 

工作原理

每个结晶工艺都会受到多个其他因素的影响。下面列出了部分最重要的因素。

工艺详情

装置 DU ZLD 结晶器

表面冷却结晶法The surface-cooling process produces supersaturation directly on the heat exchanger surface. The supersaturation in the heat exchanger is the highest in the entire crystallizer. Incrustations on the heat transfer surface and eventual plugging of the tubes are the normal consequences. This can be an acceptable situation for discontinuous operation, because with each next batch the incrustations may be dissolved again. For continuous processes, however, the surface cooling is only an option if the low operating temperature required in the crystallizer makes vacuum cooling crystallization impractical. If a continuous crystallizer must employ surface-cooling, especially large heat exchanger surface area is supplied, in an effort to increase the operating cycle.

VACUUM-COOLING CRYSTALLIZATION
Vacuum-cooled crystallization is the preferred cooling crystallization method for continuous operation. Because cooling is generated by adiabatic expansion of the solvent, and the condensing of the vaporized solvent is done in a separate heat exchanger, scaling of cooling surfaces is not experienced. Vacuum cooling becomes uneconomical (or impractical) only if operation at very low temperatures is required.

EVAPORATION CRYSTALLIZATION
The evaporative crystallization is generally a vacuum process, much like vacuum-cooled crystallization. The difference is that this process is independent of the concentration and temperature of the feed solution. External heat can be added to the system and the concentration of mother liquor can be adjusted by evaporation. Like vacuum-cooled crystallization, there are no special encrustation problems in evaporative crystallization. Operating difficulties may arise in the case of concentration of inversely soluble substances, like some sulfates and carbonates. In such cases the same encrustation model exists as in surface-cooled crystallization. High suspension velocities in the heater tubes and high suspension density (to increase the desupersaturation rate) and can improve the operating cycle. Multiple-effect evaporative crystallization plants are supplied in cases where low energy consumption is especially important.