Heat Sensitive Dryers
Kathabar dehumidifier pared with gelatine dryer saves 332 tons of regrigeration
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Having manufactured and sold over 80% of the gelatine dryers in the world, Kathabar Inc. has broadened its command over this industry with the recent sale of a gelatine dryer and Kathabar desiccant dehumidification system to a major chemical company in India. Just entering the gelatine market, the company came to Kathabar for its equipment needs. Based upon the desired production rate, Kathabar was able to size and supply a continuous gelatine dryer system and recommend a 29,000 cfm Kathabar dehumidification system to be used in conjunction with the dryer.
Due to its heat-sensitive nature, drying of gelatine is a difficult and exacting process. A scraped surface heat exchanger extrudes lacerated gelatine "noodles" from a gelatinous liquid, creating the greatest possible surface exposure for drying. An oscillating belt then distributes the "noodles" onto the dryer conveyor.
Kathabar desiccant dehumidification equipment, positioned adjacent to the gelatine dryer, removes a tremendous amount of moisture from the air to allow for high drying efficiency. In the first zone of the dryer, 20% RH air is needed so moisture can be extracted from the gelatine by vapor pressure differential. In subsequent dryer zones, higher temperature and humidity air completes the gelatine drying to the desired moisture content.
Also very important to the process, the Kathabar unit removes impurities from incoming air. Kathene, the liquid desiccant used in Kathabar systems, destroys 94% of airborne bacteria, virus and mold. All the air in the dryer is conditioned by the Kathene solution, providing a tremendous benefit to food and pharmaceutical users of the dried gelatine product.
The air inside the dryer is moved through the gelatine bed at optimum velocities by efficient, low horsepower fans. In each dryer zone, heating coils are used as the air is directed upward and downward through the sequential zones of the dryer. Conveyor speed and drying temperatures vary with the gelatine concentrations and extractions. At the discharge end, the product is broken up by a rough grinder in preparation for further processing and storage.
Complicating the process further in this instance was India's climate, where they experience a monsoon season. With the gelatine dryer process requiring 100% outside air, a Kathabar liquid desiccant dehumidification system was the ideal choice to supply conditioned air to the dryer. Kathabar systems are capable of removing up to 150 grains of moisture from the air, three times the amount of moisture a dry desiccant system can handle. In this design, the Kathabar system is able to supply 20% RH even under monsoon conditions. Kathabar removes 2,200 pounds of water per hour from the air; that is 52,800 pounds of water per day since this is a continuous, 24 hour operation.
In effect, the Kathabar dehumidification system "weatherproofs" the dryer. It allows the dryer to produce a better and more consistent end product all year long, regardless of outside weather conditions.
The pairing of Kathabar dehumidifiers with continuous dryers also results in considerable energy savings for the customer. Supplying Kathabar air to the dryer allows an energy efficient use of waste heat from the dryer into the Kathabar process. Adding to the savings is the use of cooling tower water as a coolant and low pressure steam for regeneration. The Kathabar system eliminates 3,980,250 BTU/Hr or 332 tons of air conditioning refrigeration, and 1,472,040 BTU/Hr of reheat energy, in this case.
These energy efficient, sanitary gelatine dryer systems are constructed of stainless steel where gelatine contacts the dryer, and an aluminum clad dryer housing. The Kathabar system is constructed of Fiber Reinforced Plastic (FRP) and non-metals for durability and long equipment life. The Kathabar dehumidification system and gelatine dryer are designed and custom built to suit the production requirements.
