Advanced generator purging technologies for cleaner and safer energy production

To remove thermal losses from medium-sized and large electrical turbo generators most power generation equipment manufacturer use hydrogen as a cooling gas. The gas purging process plays an important role in preventing explosive atmospheres during the commissioning and decommissioning of this type of generators. Until now, it has been common practice to use carbon dioxide (CO₂) as an inert gas in industrial applications. CO₂ is mostly supplied in liquid form and must then be converted to the gaseous state in a complex process, e.g. CO₂ flash evaporation process. As an innovative new solution, the use of argon has been researched as an alternative to the common practice of using CO₂. Argon is a noble gas with a very low critical temperature, meaning that it is also gaseous at very low ambient temperatures and can be applied at high pressure. A comparison with the relevant physical properties of other gases used in turbo generators showed that this gas can be used as an adequate alternative gas for generator purging. There are many advantages, such as reduced outage time, system simplification and safety improvements. After tests in the generator test field and practical tests in power plants, the patented purging process with argon is now used as a standard procedure for all new Siemens generators and is available as an upgrade for existing power plants.