Utility stations are required throughout the plant at various levels for supplying utility services like nitrogen, plant air, water and steam. Utility stations are so distributed that any vessel can be supplied with utility services with hoses of 15 meter length.
Nitrogen is an inert gas. It is required for purging services. When a particular vessel is taken out of service for maintenance purpose, all gases inside it must be purged with nitrogen. Care must be taken that all nitrogen is removed after purging before any maintenance personnel can enter the vessel, otherwise due to lack of oxygen, service personnel may die.
Plant air is used for various cleaning purposes like cleaning of shell and tube heat exchanger tubes, plate heat exchanger tubes etc. It is also used for cleaning of tanks.
Service water is used for cleaning purpose like cleaning of shell and tube heat exchanger tubes, general cleaning of floors, vessels etc.
Steam is used for cleaning of vessels, heating of parts of vessels, cleaning of tubes of heat exchangers etc.