Control Tank Measurement From 1 Of 3 Valves

[Peter Nachtwey]

Of course, I inferred a lot of teeth there and I could be completely off base. It wouldn't be the first time.

If this is a power plant with a turbine, it would be nice to know up front. Why must we, mostly drbitboy, always need to pull teeth.

Ex-Nuke here.

I think drbitboy did a pretty good job but water that goes through the turbine does not go through the cooling tower. The water chemistry of what goes through the turbine is very tightly controlled. If there is a turbine, it has a condenser that cools the turbine water and create a vacuum as the stead condenses to water, that "sucks" more steam through the turbine. The water that cools the condenser goes to the cooling tower.

In my experience it was sea water that cooled the condenser. Land based systems have cooling towers for dissipating heat.

 

[drbitboy]

If this is a power plant with a turbine, ...l

I did not mean to infer this process is a power plant or that this water was from a turbine process. I am quite aware that @Peter is correct when he says boiler/turbine water does not go to a cooling tower, and that managing boiler/turbine water chemistry is a whole 'nother level.

I was only using the analogy of the steam turbine boiler feedwater to introduce and define the term "blowdown" into the discussion.

Without blowdown, I don't see any way to reduce the concentration of dissolved solids that would build up in a cooling tower system that is

1. recirculating most of its water,
2. evaporating (losing) some water as vapor, but keeping the dissolved solids that came in with the vapor when it was water, and
3. gaining makeup water that is bringing in new dissolved solids.

(1) and (2) do not appreciably change the total quantity of dissolved solids in the system; (3) brings in new dissolved solids. Therefore, since the volume of water in the system is more or less fixed, the concentration of dissolved solids, and its proxy EC, must increase over time in that system, that is, absent any blowdown. It's a straightforward material balance.

 

[drbitboy]

The water that cools the condenser goes to the cooling tower.

In my experience it was sea water that cooled the condenser. Land based systems have cooling towers for dissipating heat.

It'd be tough to install a cooling tower on a sub .

Land-based systems that don't have better sources of cooling use cooling towers. E.g. many use sea- or fresh-water, if they are oceanside (Pilgrim Station, Plymouth, MA), lakeside (AEC Cayuga, Ithaca, NY; R. E. Ginna, Rochester, NY), and riverside (Grand Gulf Nuclear, Port Gibson, MI).

Some also use cooling ponds, which trade the higher efficiency of 100% evaporative cooling and a smaller footprint for of a larger cooling surface and longer residence time and a mix of evaporative and lower-efficiency convective cooling; this choice in might be driven by a locale where makeup water is harder to come by.


In the end, it's all about surface area..

 

[Peter Nachtwey]

It'd be tough to install a cooling tower on a sub .
The ocean works well except in the tropics.

Some also use cooling ponds, which trade the higher efficiency of 100% evaporative cooling and a smaller footprint for of a larger cooling surface and longer residence time and a mix of evaporative and lower-efficiency convective cooling; this choice in might be driven by a locale where makeup water is harder to come by.

Yes, when I went to nuke school I trained on S1W which was the prototype for the Nautilus. The reactor was relatively small compared to modern ones and by the time I got there it was over 20 years old so they never ran it above 50% of full power. S1W had cooling ponds. However, they would "steam" or fog like crazy in the winter time. That was water evaporating.

In the end, it's all about surface area..

And temperature differences.

 

[drbitboy]

And temperature differences.

and dewpoint.

 

[joseph_e2]

My steam experience (a loooooong time ago) was on a cargo ship, and seawater temperature made a big difference. Winter North Atlantic vs Suez canal was quite a spread.

 

[teempade04]

A pressure transmitter can be used to determine the liquid level in a tank, well, river or other body of liquid. The pressure at the bottom of a liquid filled container is directly related to the height of the liquid. The transmitter measures this hydrostatic head pressure and gives the resulting liquid level.

 

[drbitboy]

A pressure transmitter can be used to determine the liquid level in a tank, well, river or other body of liquid. The pressure at the bottom of a liquid filled container is directly related to the height of the liquid. The transmitter measures this hydrostatic head pressure and gives the resulting liquid level.

Actually it gives the differential between the two fluid media's heads.

 

[Peter Nachtwey]

My steam experience (a loooooong time ago) was on a cargo ship, and seawater temperature made a big difference. Winter North Atlantic vs Suez canal was quite a spread.

Yes.
Creating a vacuum in the turbine condenser in the northern latitudes is much easier.

 

[Peter Nachtwey]

drbitboy still hasn't extracted the tank size and what the outflow is.

A couple of years ago I wrote an article title something like "when time constants aren't constant. It may apply to this application if the tank level changes.

 

[drbitboy]

drbitboy still hasn't extracted the tank size and what the outflow is.

Nah.

Tank level is a canard; the process to be optimized is fundamentally continuous, even if filling the tank is batch. So tank size does not matter, but we have it and it's about 3m³.

Outflows (plural) are more interesting, but also important is the EC (proxy for solids) of each outflow e.g. cooling vapor EC would be zero, but if there is entrainment of droplets it could matter. Blowdown EC will be that of the the circulating water, so somewhere between 2k and 4k.

Cost functions of the different water sources are necessary to optimize this.

The solution is probably analytical, but even if it takes a numerical approach it can be solved symbolically.

So, nah, the numbers are not important at this point.