Crystallizers concentrate the feed into solid crystals and pure water. Crystallization, a solid-liquid separation method, produces solid crystals from a liquid solution. Crystallizers can eliminate liquid waste, achieving zero liquid discharge (ZLD). While, primary nucleation forms crystals; secondary nucleation drives mass creation, fostering crystal growth in crystallization. Evaporative crystallization and cooling crystallization are two different types of crystallization.
A crystallizer is a device that delivers a heated saturated solution to a insulated, sealed vessel maintained under a vacuum. So, the solution evaporates and cools adiabatically, resulting in crystallization. Hence, flashing the solution in a vacuum progressively lowers the solution temperature, leading to crystallization as the solubility of the salt decreases. Moreover, preheating can be done with the resulting vapor stream. Alaqua is a vacuum crystallizer supplier in USA that also supplies other processing equipment to meet various industrial demands.
Process of Vacuum Cooling Crystallization:
Industries primarily employ vacuum cooling crystallization for salts that experience a decrease in solubility as the temperature decreases. The multi-stage vacuum crystallizer K1-4 receives a warm, nearly saturated solution. In this situation, we gradually decrease the pressure, causing the solvent (water) to evaporate and the solution to cool to the boiling point. Moverover, lowering the temperature results in the crystallization of salt. Therefore, air drawn in at the bottom of the crystallizer (air agitation) keeps this in suspension and transports it to the exit. Hence, the suspension pump SP propels the suspension to the cyclone ZY for thickening. Centrifuge Z then separates the liquid. Hence, utilize Dryer T for drying the salt. Use cooling water in MK to condense vapor; warm mother liquor in BK. Steam jet pump D lowers pressure, aided by vacuum pump VP for inert gas removal.
Vacuum Crystallization offers the following advantages:
- Crystallization under control
- Crystals are larger and more uniform
- The authorities reduce fines
- The color formation decreases.
- Crystal yield is high
Characteristics of Vacuum Cooling Crystallization
- No cooling surface incrustation (fouling) occurs as there is no need for cooling surfaces in the form of heat exchangers during evaporation. Consequently, the time between cleaning processes is maximized.
- After separating salt, you can recover heat by reheating the draining solution.
- It is feasible to operate with partial loads in a flexible manner.
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- You can use it in various ways.
- Impeller with a hydrodynamic design.
- Calandria has a smooth bottom and a low head for better circulation
- We quickly mix the seeding material.
Variants of Vacuum Cooling Crystallization-
- In order to optimize heat recovery, the number of steps should be increased.
- With or without separation of salt.
- Horizontal crystallizers with air agitation, an external circulation circuit (Forced Circulation, FC), or vertical crystallizers with a draught tube and bottom flange stirrer (Draft Tube Baffled, DTB).
- Engineers create vacuum generators by utilizing vacuum pumps and/or steam jet pumps.
- Using acid condensation or refrigerating equipment and refrigerants achieves the reduction of pressures and discharge temperature in the solution/suspension.
- The last-step vapor condenses in mixing or surface condensers.
Alaqua is a crystallizers supplier in USA along with other processing equipment suppliers to fulfill various industrial processing equipment requirements worldwide. Along with processing equipment suppliers they also provide their services for equipment fabrication, commissioning and installation services, personnel training, field services, retrofitting services, and troubleshooting services. To know more about our processing equipment and services, feel free to contact us today!
