Indirect Air/Gas Heating
General
Air heaters or inert gas heaters are commonly
considered when products, process operations, or the facility environment
are potentially compromised by using direct drying/heating systems.
Because issues including plant layout, local
regulations, and fuel type affect these considerations, many of the
processes in this section and the preceding section are served by
both indirect and direct heating.
Process Uses
Two general processing categories are considered:
1. Food products cooking, baking, and drying.
- Roasters used in coffee and cocoa processing
- Baking ovens used for breads, cakes, etc.
- Toasting and drying systems for cereals
2. Finish drying and curing systems.
- Dryers following painting and
or final cleaning operations in furniture and metals fabrication
industries (transportation & industrial equipment, beverage
cans, etc.)
- Dryers used in finishing periodicals and newspaper
production processes
Integrating for Cogeneration
Air heaters are often industrial versions of fired furnaces
used in HVAC systems. Although many of the operations mentioned above
require only modest temperature heat (200-600F), the heater itself
may have radiation induced "hot side" temperatures above
1,500F. A new heat exchanger would probably be needed.
For more information on each application: