sci.energy

On Feb 22, 6:14=A0pm, "zzbun...@"
wrote:
> On Feb 22, 7:09=A0am, mytheo wrote:
>
> > Hello,
>
> > can anybody help me with a reference to find out the time needed for
> > various types of power plants (coal, lignite, CCGT, gas turbine, etc)
> > to cool down after they are shut down? The shut down costs would also
> > be of interest. Thanks a lot for helping!
>
> =A0 =A0Well, it depends what you mean by "cool".
> =A0 =A0The coolants go from operating temperatures, like 500 to thousands
> of degrees
> =A0 =A0to stall tempertures, like 220 degrees, fairly quickly, like an
> hour or so.
> =A0 =A0But it could be days of even weeks before you could do any
> maintainence
> =A0 =A0of some of the places, but of =A0a lot of the toxic gases.

I only have experience with coal fired plant, so I will restrict my
comments to those. Typically a boiler can be force cooled to ambient
within 24 hours, merely by running the draft groups. This applies to
boiler auxilliaries as well. Turbine auxilliaries typically take a day
or two to reach ambient. A turbine can typically be force cooled ( at
< 16 =B0C/hr ) to the point that it can be taken off barring within
about three to four days and five to seven days to be cooled to
ambient.