ASME PTC 4.2

Description / Abstract: OBJECT AND SCOPE

This Code appIies to the pulverizing system as a whole, including all the component parts necessary to take the raw coal, hot air and tempering air at the system inlet, and deliver pulverized coal in proper mixture with air and/or flue gas at the desired temperature at the outlet of the system. This Code applies to the most commonly used systems.

The direct-fired system in which pulverizers deliver the coal directly to the burner. This system usually comprises the following equipment:

Pulverizer and classifier

Feeder

Exhauster or pulverizer fan

Air inlet and tempering air connection, including control damper

Discharge coal and air piping, including valves

Motors and/or steam drives

Sources of hot air or flue gas

Figures 1 and 2 iIlustrate the arrangement of these components in pressure and suction systems for direct firing.

The storage system in which the coal is pulverized and stored in bins from which it is fed to the burners as needed. This system usually comprises the following equipment:

Pulverizer and classifier

Feeders, raw coal and pulverized coal

Exhauster or pulverizer fan

Pulverizer and hot flue gas fan

Coal and air piping including hot air inlet damper, cold air damper, and vent damper

Motors and/or steam drives

Source of hot air or flue gas

Vent cleaning equipment, which may be vent cyclone, concentrators or filters

Cyclone, cyclone air lock

Vent fan

Figure 3 illustrates the arrangement of these components for a typical storage system.