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Steam is a motive force used to generate electric power |
What is steam?Sorry, but we need to get everybody on the same page here. Steam is water vapor, produced by the application of heat to water. In order for steam to do work and serve as a useful energy source, it must be under pressure. There can be applications that employ steam at atmospheric pressure, but most are pressurized.
The heat goes on, the water boils, steam is produced and flows through the piping system to where it is used. Sounds simple, sounds easy. It is not. There are intricacies of designing and operating a steam system that determine its raw performance, as well as how efficiently it uses the fuel or other heat source employed to boil water. Steam utilization equipment is also carefully designed to provide its rated performance when supplied with steam of a given condition.
Steam at any given pressure has a saturation temperature, the temperature at which the vaporized water content of the steam is at its maximum level. Heat steam above its saturation temperature and you have superheated steam. Cool it below the saturation temperature and vapor will start to condense. The way in which the steam is to be used determines whether, and how much, superheat is desirable or necessary.
- Turbine operations benefit from properly superheated steam because it avoids exposure of the turbine to liquid water droplets, generally a source of surface erosion and other accelerated wear.
- Heat exchanger performance is based upon certain inlet conditions, one of which is the degree of superheat.
- Maintaining sufficient superheat throughout a continuously operating steam system minimizes the need for, and size of, a condensate return system
Some process requirements may focus on temperature of the delivered steam, without regard to superheat level. Others will rely on a specified level of superheat. The application scenarios are vast, with equipment available to accomplish whatever is needed.
Either operation can be accomplished with a specialized heat exchanger or other device that extracts heat from the steam. Another option relies on the addition of atomized water to the flowing steam to manage temperature or superheat level. Share your steam system challenges with steam system experts, leveraging your own knowledge and experience with their product application expertise to develop an effective solution.