Dryer

7 Pages 1646 Words

II. Problem Statement
We have been using a high cost desiccant in our facility to remove water from an air stream. Someone has suggested that we test “kitty litter” and a different desiccant as potential replacements. However, these materials, although cheaper than the current mole sieve material, are not so inexpensive that we can simply discard them when they become saturated. Your job is to:
• Determine the H2O uptake for each of the materials.
• Determine the optimum drying conditions for each material.
• Do not exceed 80 deg C in the batch dryer.
• Scale up the process to 12 T/day on a continuous belt dryer that is 4 ft wide and 50 ft. long for the best candidate.
• Report your findings to management with your recommendations.
• Temperature control should be included.
• Include PFD in both reports.


III. Introduction
A desiccant is a material that readily soaks up water vapor from surrounding air. The desiccant will continue to adsorb moisture until it becomes saturated. These desiccants or adsorbents are generally classified as amorphous or structured, and hydrophobic or hydrophilic. Many different substances exist which are capable of adsorbing, but few are of industrial significance. Commonly used industrial desiccants include silica gel, molecular sieves, activated carbon, and activated alumina. These desiccants are used to eliminate moisture or other impurities from gas streams.
Once the desiccant is saturated with moisture, it can be recycled through a process of regeneration. The regeneration process is a form of drying, in which water or some other liquid is evaporated from a solid material to reduce the content of liquid to some acceptable value. During regeneration, hot air or inert gas is used to dry the adsorbent. This is a form of thermal vaporization which is a highly energy intensive process.
Various different types of drying equipment are available depending on the ...