About Boilers

Boilers are steam-producing devices used in the process and power generation units. Boilers where steam is generated to generate power alone (as in thermal power generation units) are called power boilers. Process boilers generally generate steam for process use, and excess steam is incidentally used for power generation also.

Boiler Auxiliaries for Efficiency Improvement

1. Air preheater (inlet air heated by flue gas)

2. Economizer (boiler feed water heated by flue gas)

3. Superheater (steam superheated by flue gas)

4. Induced draft/forced draft fans (air circulation devices)

5. High-efficiency burners (better atomization)

6. Auto damper control (air control device)

7. Oxygen monitor/combustion controller

Figures D-1 through D-3 show a typical air preheater layout, an economizer layout, and a superheater. Figure D-1 shows how air passes in the shell side. Flue gas passes through tubes as shown. This increases thermal efficiency by 9 11%. In figure D-2 the main objective of economizer is to increase the thermal efficiency of the boiler by preheating boiler feed water by exhaust flue gases.

Figure D-1: Typical air preheater layout

Figure D-2: Economizer layout

Superheater is designed...