Components
Design Criteria
Boiler types
Representative firetube boilers
Representative water-tube boilers
Water walls
Boiler installation
Furnace
Superheat
Boiler accessories and trim
Combustion equipment
Spreader stoker
Conveyor stoker
Underfeed stoker
Coal burners
Gas and oil burners
Operation and performance
Heat balance of a steam generator
Some important points under development
Components
Design Criteria
Boiler types
Representative firetube boilers
Representative water-tube boilers
Water walls
Boiler installation
Furnace
Furnace Heat Release Rates
Many types of furnace walls are in use;
1. Solid masonry
2. Air cooled masonry walls
3. Partially water cooled walls
4. Water jacketed furnace
Materials chiefly used are fire clay, silica, kaolin, diaspore, alumina, and certain products of the electric furnace.
Fire clay bricks are preferred because of their low cost whenever they give satisfactory results.
Ordinarily optical thermometers used with furnaces give wall temperatures.
Superheat
Boiler accessories and trim
Combustion equipment
Spreader stoker
Conveyor stoker
Underfeed stoker
Coal burners
Functions of a burner
1. There is stability of ignition.
2. 2. Effective adjustment for control of point of ignition and resulting flame shape.
3. Complete combustion
4. Heat unformly developed in flame
5. Adequate protection against overheating, internal fires, and excessive abrasive wear.
Pulverised coal burners are classified as long-flame, short-flame (or turbulent), and tangential burners.
Cyclone burner
Gas and oil burners
Operation and performance
Operation of the boiler consists in ascertaining that equipment is following the load and functioning normally, but also in making secondary adjustments which refine the thermal efficiency beyond the normal abilities of the usual complement of automatic equipment. Automatic equipment must be watched through instruments for periodic inspections, load shifts between multiple units made, critical points for pressure, temperature, etc., inspected from time to time and other precautionary actions taken.
In most plants, especially, central stations, part of the supervision is "taking log", ie the record of flows, pressures, material quantities, and other physical data. These are supplemented by samples of coal, water, etc., for testing in the plant laboratory. Performance of the plant as a whole, or parts of it are computed at intervals from such data. Then there is always a certain amount of maintenance and repair. In larger installations, there are specialized groups such as operations, tests, plant improvement, maintenance, repair etc.
Heat balance of a steam generator
