A Boiler is a piece of equipment which acts as a closed vessel to convert the water inside into steam. In order for this to happen chemical energy from a fuel source such as oil or gas is converted into heat by combustion. The heat is then transferred to the contained water, thereby increasing the pressure and eventually converting the liquid form into steam.
Boilers are one of the most fundamental systems of a refinery or chemical processing plant. They are literally the pieces of equipment that keep the plant up and running. Most industrial boilers fall into two broad categories of boiler types:
Fire-Tube Boilers and Water-Tube Boilers.
In fire-tube boilers, hot gas passes through one or many tubes, which through thermal conduction, heats the water surrounding them. In water-tube boilers, water circulates inside the tubes and is heated externally by hot gases generated by the furnace.
The boilers are manufactured as single-pass, two-pass or multi-pass, horizontal or vertical, single or two-drum, with natural or forced circulation. The concept is chosen with respect to the required parameters, operating requirements and local conditions.
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