Bi-Drum boiler is generally used to generate high steam-pressure required for incidental power generation or cogeneration. It is also used for saturated steam applications, which demand uninterrupted operation on highly choking fuels. This boiler is rugged and can operate continuously throughout the year. In addition, since it has small water content, it responds rapidly to changes in loads and heat inputs.
In Bi-Drum boilers, water is circulated inside the tubes, with the heat source surrounding them. The energy from the heat source may be extracted as radiant or convective & conduction. The furnace or radiant section is an open area accommodating the flames. The walls of the furnace section are lined with finned tubes called membrane panels, which are designed to absorb the radiant heat from the flame.
The convection section is designed to absorb the heat from hot gases by conduction and convection.
Bi-Drum boilers are categorised by:
- Reservoir drum position - longitudinal or cross drum
- Number of drums - single or double