DSK wrote:
Actually, they aren't. There is no bypass from the HP and/or IP
turbine directly into the condenser in any plant I've ever steamed,
naval or civilian. So, there may be many plants out there with such
valves, but they're certainly not standard.


Nav wrote:
Well I guess this company for one never sells any?

http://www.emersonprocess.com/fisher...ditioning.html

Thanks for one good laugh today. Did you read the description of these
valves? Did you just type "turbine bypass" into Google and grab the
first link that came up?



Doug please try to engage your brain. In a plant where multiple engines
are used there has to be a way of taking one of them off line without
trashing steam flow in the whole plant right?

Are you under the impression that a set of HP, IP, and LP turbines, all
geared to a common shaft, are considered "multiple engines"? What you're
talking about is a main steam loop.

A main steam loop has to supply power to propulsion engines (turbine or
whatever), feed pumps (recip or turbine), SSTG (do you what that stands
for?), and also feeds steam into auxiliary systems through pressure
reduction control valves & sometimes via desuperheaters. Some systems
have forced draft blowers on main steam also, but most FDBs are on an
aux loop.

A main steam loop is laid out similar to a firemain loop... the idea is
to supply all stations with redundant paths, so that you can isolate any
part of the system and still keep the rest running. Each section and
each piece of equipment will have stop valves and/or guarding valves.
Your "bypass valve" is for something else entirely.

... Think about what happens
when a generating turbine trips! You can't just close the turbine inlet
valve as the boiler pressure would skyrocket.

Why? Do you not have combustion controls down there? Or even firemen
that can stay awake on burner watch?


... What you do is open a
bypass valve.

That depends on the plant.

... In big plants you may also inject water to cool the steam
(it's pressure is dropped by adiabatic expansion after the valve) and
thence to the condenser.

That's not what is done on any marine plants I ever heard of, or for
that matter, any stationary ones. It would be incredibly wasteful of
fuel. Hey Rick, you following this?


If you have a plant where one engine takes the steam from another and
you want to drop the second off line you first open a bypass valve. So,
that's all, why did you even argue about it with me?

I'm not arguing, I was trying to explain some of the basics of what
likely happened when the watch officer on the bridge of the Titanic
tried to dodge that iceberg. Since this discussion has wandered so far,
I've mostly been laughing at you... trying to explain 'condensate
depression' with an integral, and confusing HP & LP turbines for
"multiple engines." Thanks for the laughs, Navvie.

DSK

That's not what is done on any marine plants I ever heard of, or for
that matter, any stationary ones. It would be incredibly wasteful of
fuel. Hey Rick, you following this?

No, have just got home a few minutes ago,brought a boat down from Alaska
and am now on my way to the airport to fly to Lauderdale for the
superyacht show ...

The only place water gets injected into the steam is in an attemperator
just before the evaporators. I cannot think of any single more wasteful
exercise than adding water to steam for any reason other than to cool
the steam going to an evaporator feed water heater running on live steam
rather than bleed steam.

Rick