Water Tube Boilers
As one of the oldest forms of steam boiler, originally dating back to the eighteenth century, Water Tube Boilers have progressed from powering small stationary steam engines and steam trains to being the powerhouse of large demanding processes with the capacity to provide very substantial outputs. They provide high quality steam, from dry saturated to high temperature superheated and, due to the heat exchanger design, have the ability to also provide very high operating pressures. They are suitable for applications requiring high steam output (up to 500 kg/s), high pressure steam (up to 160 bar) or superheated steam (up to 550°C).
Babcock Wanson has an experienced team of engineers to design Water Tube Boilers to meet your specific application, with mechanical staff and technicians able to assist with and arrange the installation works and carry out the boiler commissioning.
A water tube boiler is typically formed of four parts, a lower feed water drum – sometimes known as a mud drum – an upper steam drum with water surface from which the steam is evolved, water tubes connecting the two drums together and a super heater / economiser section (depending on the quality of steam required). Water circulates by convection between the two drums with the heat passing over the banks of tubes. Cooled water passes down specific tubes and the reheated water rises to the top of the boiler into the steam drum. Saturated steam is drawn off the top of the drum for export to the user or passed through a subsequent superheater within the exhaust gas stream to raise the temperature further. The cooler water from the bottom of the steam drum pre-heats the feed water supply as it returns to the feed water drum.
To improve energy efficiency, exhaust gases are also used to pre-heat the air blown into the furnace and warm the feed water supply.
Advantages of Water Tube Boilers:
- Steam production from 4.5 to 80 t/h.
- Saturated steam and superheated steam up to 550°C.
- 95+% efficiency, without additional heat recovery system.
- 10 – 90 barg typical service pressure.
- Suitable for indoor or outdoor use.
- Can be used with all types of liquid and gaseous fuels.
- Construction compliant with PED: 2014/68/EU and Harmonised Standard EN-12952.
- Different levels of attendance at the boiler from attended mode, i.e. permanent local supervision to unattended operation for periods of up to 72 Hours.
- Very Reliable; the design of the water tube boiler is very robust due to the relatively small diameters of the steam and mud drums and their flooded operation.