Steam is an invisible gas generated by adding heat energy to water in a boiler. Enough energy must be added to raise the temperature of the water to the boiling point.
Then additional energy addition changes the water to steam – without any further increase in temperature.
Steam is a very efficient and easily controlled heat transfer medium.
It is most often used for transporting energy from a central location (the boiler) to any number of locations in the plant where it is used to heat air, water or process applications.
Steam is the gaseous/Vapor phase of water at pressurized condition. If water is heated into closed vessel / container (not completely filled) it will vaporize. Gas is lesser in density and larger in volume compared to Liquid of the same quantity, it starts accumulating in the empty spaces of the vessel, above water, and gradually increases the pressure inside. On further heating the water, it converts to steam at a certain pressure depending on the volume it occupies.
Steam today is an integral and essential part of modern process technology envisaging heat transfer. Its use is popular throughout industry for a broad range of tasks from mechanical power production to space heating and process applications. It would be difficult to imagine industries like Food, Textile, Chemical, Oil & Petrochemical, Pharmaceutical, Power, Heating and Transport industries, exist or perform without the abundant use of steam.
Water is plentiful in Nature and inexpensive. It is non-hazardous to health and environmentally sound. In its gaseous form, it is a safe and efficient energy carrier. Steam can hold up to five to six times as much potential energy as an equivalent mass of water. Steam can be generated at high pressures to give high steam temperatures. More heat energy is contained in high temperature steam, so its potential to do work is greater.
Modern Shell Boilers are compact and efficient in their design, using multiple passes and efficient burner technology to transfer a very high proportion of the energy contained in the fuel to the water, with minimum emissions.
The boiler fuel may be chosen from a variety of options, including combustible waste, which makes the steam boiler an environmentally sound option amongst the choices available for providing heat (like Coal, Fuel Oil, Fuel Gas, etc).
Highly effective heat recovery systems can virtually eliminate blow-down costs, return valuable condensate to the boiler house and add to the overall efficiency of the steam and condensate loop.