In physics class, bucket of water experiment is used to demonstrate the effect of centrifugal forces. This experiment is fairly easy to carry out as we need a bucket of water & someone to turn it around. Its amazing to see water stays on the inside as bucket goes around and more amusing when water accidentally spills over your friend. Centrifugal pump design harnesses the concept of centrifugal force in discharging liquids. In its simplest form centrifugal pump is about an impeller rotating in a casing accelerated the incoming liquid and discharge them out. This enable liquids to move against gravity, through pipeline, into pressure vessel & various other plant applications.
While centrifugal pump moves liquids around. There are other centrifugal machines used in gas applications. Centrifugal compressor & fan are rotating machine operating on the principle of centrifugal force to move gases around. Like centrifugal pump, both compressor and fan have an impeller rotating within a casing. Liquids & gases have different physical properties which has significant influence on the machine design and construction. All these physical properties will affect not just the machine itself it affects the design and construction of the associated piping and ducting. Centrifugal pumps looks very similar to centrifugal fan as both can be constructed using a two bearing system with overhung impeller. Obviously, fan and pump are not interchangeable. Plates used for fan impeller looks deceivingly easy to construct.
PTA plant multistage centrifugal air compressor delivers compressed air to oxidation reactor and it needs a house by itself. This humongous machine takes not only big space but hefty electricity bill. One compressor train is fitted with steam turbine and the other train with turbo-expander to take advantage of the reactor off gas after the plant is up and running. By hooking up drivers like steam turbine & turbo-expander the cost of electricity to operate the air compressor can be reduced. Thus, a cost saving to company.
Centrifugal force is a benign concept that we learn in physics that gives rise to wide ranging applications in oil & gas industries. In fact, these centrifugal machines has its application in multitude of services essential to our modern living such as water supply, power generation & refrigeration.