Talk of generators and the first thing that comes to mind is power (electricity) or water pumps. These are certainly valuable equipments as they do not only make work easy but are also highly functional. There are also other types of generators and although some are very small in size, they are certainly effective for what they are designed. One type of generator that is very useful is the heat recovery steam generator (HRSG).
From its name, this is a generator designed to specifically recover heat from a stream of hot gas. It literally transforms the heat that it recovers into steam, which can be used in different ways including driving steam turbines. Presently, HRSGs are widely used in ocean vessels and institutions for the purpose of producing safe and reliable electricity. This type of generator features four important components that make it operational; super heater, evaporator, water pre-heater and an economizer.
There are basically two types of HRSGs; vertical and horizontal HRSGs. While a horizontal HRSG has its exhaust gas flowing horizontally above tubes positioned vertically, a vertical HRSG has its exhaust gas flowing vertically above tubes positioned horizontally. The two types of HRSG can be designed to be of either single or multi pressure levels. A single pressure HRSG only features a single steam drum, which means that generation of steam is at a single pressure level. On the other hand, a multi-pressure HRSG is designed with either two or three stem drums, meaning that it has low, intermediate and high pressure levels. In this regard, each pressure level has an evaporator area for conversion of water into steam, which goes through super heaters, which in effect raises temperature above saturation point.
Another type of HRSG that has been availed into the market is the Once-Through Steam generator. This type does not feature any super heater, economizer or evaporator. Instead, its inlet allows for a clear pathway, which provides for high flexibility and efficiency. This is made possible by the fact that there are no steam drums, which makes it possible for quick steam production.
Like with other types of generators, HRSGs are available in different models. They are designed and manufactured by varied companies. Apart from local appointed generator dealers, they are also available from various online stores that specialize in selling generators and other equipments. They can also be purchased directly from manufacturers through their websites. HRSGs are available in packages of assembled units.