What Is the First Steam Blow Test in Commissioning


Thread Starter


Hi Folks,

Sorry if the question is stupid, but I'd like to know what is the first steam blow step during commissioning of a new power plant?

What does it involve? What does it need to be done prior to start this test on the turbine/generator and boiler? How long it last ?

Let's take for example a steam turbine coupled to a 500MW H2 cooled generator.

Thank you very much

First, all of my experience with steam blows is from combined cycle plants, not straight steam plants. However, the purpose of the steam blows is to clean all of the construction "junk" in the steam lines prior to admitting any steam to the steam turbine. The type of generator coupled to the steam turbine does not change the steam blow procedure. What matters is the steam turbine design.

The general procedure is to separate the steam lines from the steam turbine just ahead of the control valves and connect a temporary pipe to the steam line that will route the steam to the atmosphere. There is a provision to install a target in the temporary pipe just downstream of the connection to the steam line. Then steam is admitted to the steam line from the boiler or HRSG. The target is not installed until after a time specified in the procedure. Once the target is installed, steam is blown for a specified time, the target is removed and taken to the lab for examination. When you get a target that passes the specified requirements, the steam blow is done. Note, a steam blow is required for each pressure level of steam that is admitted to the steam turbine. And, if you have a reheat turbine, the temporary piping gets more interesting.