Process calculations for partial-recycle dryers

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Chemical Engineering

OSTI ID:218578

Cook, E M ^[1]

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1. Energy Savings Consultants, Boynton Beach, FL (United States)

Throughout the chemical process industries, the majority of drying operations--used to produce dry powders, grains, granules, crystals, pellets, flakes and chips--rely on directly heated dryers, which use a large stream of hot air to release the unwanted moisture from the wet material. In their most common configuration, directly heated dryers use a once-through flow of drying air, and the air and liberated vapors are exhausted to the atmosphere. A variation on this dryer setup is the closed-loop design, in which the entire hot air or gas stream used to heat the product is confined and eventually recycled. Between once-through and closed-loop systems, there is a third class of dryers: partial-recycle systems. In a partial-recycle dryer, a substantial portion of the outlet air is returned to the dryer, minimizing heating requirements and effluent-treatment requirements. The paper discusses the recycle process, recycle system layouts, software to ease the calculations, key inputs needed to design and operate the dryer, impact of moisture on performance, calculation procedures, equipment sizing, and the use of psychrometric charts.

• OSTI ID: 218578
• Journal Information: Chemical Engineering, Journal Name: Chemical Engineering Journal Issue: 4 Vol. 103; ISSN CHEEA3; ISSN 0009-2460
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
COMBUSTION
COMPUTER CALCULATIONS
COMPUTER CODES
COMPUTER-AIDED DESIGN
DRYERS
ENGINEERING
NATURAL GAS
OPERATION
PSYCHROMETRY
SCRUBBERS