Crystallizers

Crystallizers can help you reduce your wastewater discharges and, in many cases, capture revenue-producing products. The technology reduces your environmental impact and help you achieve zero liquid discharge. The crystallizers are simple to install, generally skid-mounted and fully packaged with all auxiliary equipment and controls. Automated controls and wash systems make the equipment easy to operate. Systems use mechanical vapor recompression (MVR) technology to recycle the steam vapor, minimizing energy consumption and costs. Crystallizers can recover specific salts that can be sold to offset operating costs. Because industrial wastewaters often contain mixtures of salts in variable concentrations, the design of an effective crystallizer system requires special expertise

Forced Crystallizers

Oslo Crystallizers

Crystallizers

Advantages

• Reduced water consumption
• Capture of revenue-producing products
• Ease of operation
• High energy efficiency

Common Processes

• by concentration
• by cooling (under vacuum or with a heat exchanger)
• by reaction or equilibrium displacement

Common Types

Forced circulation crystallizers

Forced circulation crystallizers are of the (Mixed Suspension Mixed Product Removal) MSMPR type and operate either on controlled or "natural" slurry density depending upon process requirements and/or unit material balance.

These systems can be either single or multiple effects and the vapor recompression concept (either thermal or mechanical) is often applied. Usually, they operate from low vacuum to atmosphere pressure.

As a rule, these units are used for high evaporation rates and when crystal size is not of the utmost importance or if crystal grows at a fair rate.

Oslo type crystallizer

Oslo type crystallizer also called classified-suspension crystallizer is the oldest design developed for the production of large, coarse crystals.

The basic design criteria are twofold:

• desupersaturation of the mother liquor by contact with the largest crystals present in the crystallization chamber
• keeping most of the crystals in suspension without contact by a stirring device, thus enabling the production of large crystals of narrow size distribution

Induced Circulation Crystallizer

The Induced Circulation Crystallizer design has been recently developed to provide additional agitation of the active volume of forced circulation crystallizers with the use of only one pump.

It has been successfully applied to the following productions:

• NaCl
• NH4ClO4
• NH4Cl