An Overview Of Boilers And The Importance Of Boiler Service And Efficiency

Boiler may be defined as a closed vessel in which water or other types of fuel are heated to generate steam. There are some boilers in which the fuel inside it does not boil, however the vaporized fluid is made to exit the boiler and this vapour is used for several applications like power generation, sanitation systems, and central heating and even in cooking.

The body of the boiler, called the pressure vessel, is made of steel or its alloy like wrought iron. Wrought iron boiler body was very famous in the Victorian era and wrought iron sheets were riveted together to make the pressure vessel. In smaller sized boilers, used in cooking applications and heating, brass or copper is used to construct the body since these can be very easily fabricated. Copper is the best choice to make the body of the boiler since it has a high thermal conductivity and a good formability, but due to the higher cost of copper, this metal is substituted nowadays with other cheaper alternatives.

The heat source in the boiler is from the combustion of fuel, which can be of different materials like oil, wood, coal or natural gas. Immersion or resistance types of heating elements are used in the electric boilers.

There are some professional organisations that specialises in defining a set of rules and standard regulations that must be followed while designing a boiler. Historically, there have been many incidents where boilers were a source of destruction of lives and properties due to faulty constructions, owing to poorly understood engineering concepts. There may be incidents where the metal sheets may rupture or the rivets can open up which will inevitably result in violent eruption. The importance of boiler service and safety in the design and construction stages are vital.

The steam or vapour generated in the boiler is carried through pipes to distant places where energy is needed. The steam carries heat energy form the boiler site to the operational site where the heat energy can be converted to any type of energy that is needed. If the boiler does not function properly or generate enough steam due to poor boiler efficiency, then the operational site will not function profitably and loss will be incurred.

Boiler efficiency is defined as the ratio of the output energy to the input energy of the boiler and this efficiency is generally expressed as a percentage. There are four different types of efficiencies that may also indicate the efficiency of a boiler and these are- fuel efficiency, combustion efficiency and thermal efficiency. The fuel efficiency defines the overall efficiency of the boiler whereas the combustion efficiency gives the ability of the burners to burn fuel and the thermal efficiency denotes the effectiveness of the heat exchangers to transfer the heat from the combustion of the fuel to the steam of the boiler.

Installation of a boiler is a costly process and herein comes the importance of boiler service and efficiency. The annual cost of fuel can be 3 times more than the installation cost of a boiler and if the efficiency of the boiler reduces then the difference in fuel cost may offset the capital cost difference. The reduction in the efficiency will also cause a reduction in the output of the boiler thereby bringing a cascading reduction in the output of the process for which the steam of the boiler was required, for example, thermal power generation. As a result the cost of the production will increase exponentially and sustaining the operation will be difficult with reduced profit.