Steam Plant Operation, Eighth Edition
Packed with illustrations and fundamental descriptions, this definitive reference keeps readers current with the latest design methods of various systems and assists in all areas of steam plant operation.
TABLE OF CONTENTS Steam Plant Operation, Eighth Edition
Chapter 5: Boiler Settings, Combustion Systems, and Auxiliary Equipment
In order to apply the principle of combustion, it is necessary to design, construct, and operate equipment. A wide variety of equipment is required to burn solid, liquid, and gaseous fuels satisfactorily. The functions that must be performed are supplying and mixing fuel and air, confining the high temperature during combustion, directing the heat to the heat-absorbing surfaces of the boiler and heat-recovery equipment, and discharging the ash and products of combustion from the unit at an emission rate within the limits imposed by environmental requirements.
5.1 Boiler Settings
As defined by today s modern boiler designs, the boiler setting includes all the water-cooled walls, casing, insulation, lagging, and reinforcement steel that form the outside envelope of the boiler and furnace enclosure and which safely contains the high-temperature flue gases that result from the combustion process. Fire-tube boilers have been supported by the brickwork setting or independently suspended from overhead steel beams. Figure 2.5 shows an older design of a horizontal-return tubular boiler supported by brickwork. Note that the boiler rests on rollers so that it can expand independently of the setting. The overhead suspension was considered best because it relieved the brickwork of extra load, kept the boiler at the proper level, and permitted repairs to the brickwork without disturbing the boiler. Figure 2.7 shows the support of a modern four-pass fire-tube package boiler. Note how this boiler design has all combustion taking place within the boiler.
Water-tube boilers may be either bottom or top supported. On a two-drum...
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