Section 1 - General
1.1 Scope
1.2 Referenced publications
1.3 Definition of terms
Section 2 - General considerations in selecting an air
preheat system
2.1 Factors affecting system applications
2.2 Types of air preheat systems
2.3 Factors affecting air preheat system choice
Section 3 - Interaction of the air preheat system with
the fired heater
3.1 Process design
3.2 Burners
3.3 Draft
3.4 Linings and heat loss
3.5 Convection section
3.6 Mechanical design
Section 4 - Selecting an air preheat system
4.1 Regenerative air preheat system
4.2 Recuperative air preheat system
4.3 Heat pipe air preheat system
4.4 Indirect closed circulating air preheat system
4.5 External heat source air preheat system
Section 5 - Safety, operability, and maintenance
5.1 Safety
5.2 Operability
5.3 Accessibility for maintenance
5.4 Performance checks
5.5 Air preheat equipment failure
Section 6 - Selecting system temperatures
6.1 Introduction
6.2 Selecting cold-end temperatures
6.3 Selecting hot-end temperature
6.4 Combustion considerations
Section 7 - Combustion air and flue gas quantities
7.1 Introduction
7.2 New installations
7.3 Retrofits
Section 8 - Duct design and damper selection
8.1 Introduction
8.2 Pressure drop calculation
8.3 Zone concept
8.4 Draft effects
8.5 Dual draft systems
8.6 Velocity guidelines
8.7 Damper consideration and selection
8.8 Duct stratification
8.9 Additional references
Section 9 - Guidelines for specifying equipment
9.1 Introduction
9.2 Ductwork and stack
9.3 Expansion joints
9.4 Dampers
9.5 Ductwork insulation and refractory
9.6 Fans and drivers
9.7 Air preheaters
9.8 Burner
Section 10 - Environmental impact of air preheat systems
10.1 Energy conservation
10.2 Stack emissions
10.3 Noise
10.4 Heat
10.5 Effluent
Section 11 - Preparing an inquiry
11.1 Introduction
11.2 Inquiry
11.3 Air preheat system checklist
Appendix A - Flue gas dew point discussion and
references
Appendix B - Data sheets
Tables
1 Fittings
2 Recommended damper types
A-1 Flue gas dew point data from oil-fired industrial
boilers
Figures
1 Air preheat system using regenerative,
recuperative, or heat pipe air preheater
2 Air preheat system using an indirect closed air
preheater and mechanical circulation
3 External heat source for air preheating
4 Recommended minimum metal temperature
5 Sample flow sheet for duct design and damper
selection
6 Moody's friction factor
7 Pressure drop for flue gases in ducts
8 Equivalent lengths (LD) for multiple piece miter
elbows of round cross section
9 Branch loss coefficients
10 Duct zones
A-1 Dew point of flue gas versus sulfur in fuel oil
(test data from industrial boilers)
A-2 Dew point of flue gas versus sulfur in fuel oil
(test data from industrial boilers and data of
Attig and Sedor)
A-3 Dew point of flue gas versus sulfur in fuel oil
(test data from industrial boilers and data of
Energy Technology, Inc.)