Overview
An international salt distribution company approached Carrier Vibrating Equipment with an uncommon request: one machine capable of producing two separate products, crushed rock salt and table salt, without requiring the purchase of two separate systems. Only one product would be processed at a time, and both salts had similar drying requirements. The complication was in how each end product was packaged and handled after drying. Carrier’s engineering team designed a custom vibrating fluid bed dryer/cooler that could be quickly reconfigured between the two processes as production demands changed.
Herausforderung
The client was purchasing already dried salt from overseas producers and wanted to reduce costs by purchasing wet, partially dried salt at a lower price and drying it in-house. The capital investment in a drying system had already been justified by the projected savings.
The two salt products created distinct processing requirements:
Rock salt was going to be bulk stockpiled for later shipment. At high exit temperatures, rock salt could continue evaporative cooling in the open air without any quality concerns, making its drying requirements straightforward.
Table salt was being fed directly into a packaging line after drying. The high exit temperature from the dryer created two serious problems. First, the heat risked damaging or melting the packaging bags. Second, table salt continues releasing moisture vapor as it cools after leaving the dryer. If the hot, still-releasing salt was immediately sealed into bags, that moisture vapor would be reabsorbed by the salt, creating solid lumps and product quality failures.
The company needed a single drying system that could handle the full output rate for rock salt and then be converted to include a cooling zone when processing table salt.
The client’s goals were:
Lösung
The client sent samples of both salt products to Carrier’s test laboratory in Louisville, KY, and was invited on-site to observe the testing process. Testing determined the required drying temperatures and residence times for each product and confirmed that a vibrating fluid bed dryer/cooler was the best fit for the application.
Unlike rotary dryers or static fluid bed systems, a vibrating fluid bed dryer can incorporate an integrated cooling zone within the same machine. The vibrating action also gently handles the salt, reducing product degradation and fines generation throughout the process.
Carrier’s engineering team developed a custom design that allowed the machine to operate in two configurations:
Rock salt mode: The full length of the fluid bed was used as a drying zone. All air was heated by a natural gas burner and blown into both sections of the plenum with the automated damper left open. This configuration maximized production rate.
Table salt mode: The automated duct damper was closed, partitioning the machine into two zones. The first section continued to operate as a dryer. The second section became a cooling zone supplied by a separate blower providing cooler air. This brought the table salt down to a safe temperature for immediate bagging while also removing the residual moisture vapor released during cooling.
The client’s PLC was programmed to manage the changeover between modes quickly. The entire vibrating fluid bed was insulated for energy efficiency. Rubber marshmallow isolation springs were included in the design to allow easy cleanup and the ability to hose down the system to remove salt accumulation.
Results
- Rock salt output: 60 tn/hr of dried product ready for bulk stockpiling
- Table salt output: 20 tn/hr of dried and cooled product ready for immediate bagging
- Single machine handles both products, eliminating the cost of a second system
- Rapid automated product changeover via PLC-controlled duct dampers
- Integrated cooling zone removes residual moisture vapor before bagging, eliminating lump formation and quality failures
- Insulated design reduces energy consumption
- Rubber isolation springs simplify cleaning and maintenance
Contact Carrier Vibrating Equipment
Carrier Vibrating Equipment engineers custom drying, cooling, and handling systems for food, mineral, and industrial processors. Contact our team to discuss your application and find out which solution fits your specific processing requirements.