Remove gas from water

[Silvermink]

Is there a setting on the purge valve that won't force water into my gas output? The gasses aren't water vapor.

[JeanDeaux]

I'm also giving this another go as it's still not making sense to me.

https://steamcommunity.com/sharedfiles/filedetails/?id=3128400909
In this configuration I've got a liquid pipe network from an ice crusher to a tank, added a heater to bring the temp up to 20°C. Steam is present (assuming from the melting/warming process even though the temp NEVER gets anywhere near close to boiling). Once in this pipe network and the temp settles from warming up, everything becomes stationary and the steam remains at a constant value.

https://steamcommunity.com/sharedfiles/filedetails/?id=3128401565
Attempting to convert that steam back to liquid, I add a Purge and Condensation valve along with a Liquid Back Pressure Regulator (set to 0%) to push out liquids into the liquid pipe network. Since I used insulated gas pipes, the steam didn't change temp and just sat there with no change. I added a radiator and a freeze icon appeared and the temp flash dropped to -167°C. Neither case cooled the steam to liquid form.

The Stationpedia clearly states that "Steam will condense back to Water if it's temperature is below it's boiling point". To this, I don't see this working as described in any attempt or fashion I attempt to test. It also states that steam is created by "rasing" (yes, that's a typo in the pedia) to its boiling point. So by their own outline, there should not be steam in this system at.

Someone want to take a shot at explaining this mechanic to me, again?

[Alizia Kaline]

Originally posted by JeanDeaux:

In this configuration I've got a liquid pipe network from an ice crusher to a tank, added a heater to bring the temp up to 20°C. Steam is present (assuming from the melting/warming process even though the temp NEVER gets anywhere near close to boiling). Once in this pipe network and the temp settles from warming up, everything becomes stationary and the steam remains at a constant value.

You forgot a parameter, the pressure. The matter state depend of the temperature, but also of the pressure.

Water with no pressure will boil, even at 20°, until the pressure is enough to maintain the liquid state. You can see this effect IRL with water drying at ambiant temperature.

You can check the state graphic on F1. Use a neutral gas like Nitrogen to pressurize your liquid pipe and maintain the water in liquid state.

For the op problem, to purge a stranger gas you can use a Purge Valve. It will remove all the gas. Reinject the vapor into your liquid pipe with a Pressurant Valve and exit the rest.

[Thiesen]

Yeah... I have gaseous H2O in my big insulated tank at like 14 degrees C... 1150 liters of water... that can't be right unless the tank is a negative pressure vessel... :-)

And yes... water will slowly evaporate at room temp in open air at 1 Bar of pressure...

[JeanDeaux]

Alright, so I need to add a pressure regulator to route some Nitrogen also generated from the ice crusher, but will likely need a pressure relief to exit some Nitrogen as the water line fills. So I need about 600W of regulation equipment just for the water system... ouch.

https://steamcommunity.com/sharedfiles/filedetails/?id=3128609001
Here's an update with your suggestion of adding Nitrogen (for anyone else experimenting). I added a Back Pressure Regulator to my (dedicated) Ice crusher, so only Nitrogen will be available in this line; set it to a value of 50kpa to be sure I always have a supply available to inject. This feeds a Pressure Valve (set to 15 kpa) to inject the Nitrogen, found I no longer needed the radiator so I removed that device. The steam did eventually condense down and now there's only Nitrogen gas in the line, success thank you. I opted to hold off on the back pressure gas to see if it's ever really needed, so we'll see.

If anyone has any further suggestions or warnings on things to come, I'd be eager to hear your insight.

[JeanDeaux]

I wonder, would this issue be self-solving as you add more and more water to the system? I'm currently at initial development of the pipe network so as I add more crushed/melted ice the pressure should increase and therefore achieve the same end result? Or does the early fill cause pipe-bursting issues with the steam build-up in the line?

[powerkek]

It's really a non-issue even without adding nitrogen. As the pipe fills with more water the steam pressure will rise, causing more steam to condense. This keeps the pressure at whatever the water graph shows for your current temperature. As long as temp stays below some 361C (was it?) and the pipe isn't 99.9% full of liquid water it won't break from steam overpressure.

Though do be careful with filling pipes too fast as condensation/evaporation takes a few seconds.

[Alizia Kaline]

Originally posted by Thiesen:

Yeah... I have gaseous H2O in my big insulated tank at like 14 degrees C... 1150 liters of water... that can't be right unless the tank is a negative pressure vessel... :-)

If there is no pressure in it, it's normal. I explained it.

[Alizia Kaline]

Originally posted by JeanDeaux:

I wonder, would this issue be self-solving as you add more and more water to the system? I'm currently at initial development of the pipe network so as I add more crushed/melted ice the pressure should increase and therefore achieve the same end result? Or does the early fill cause pipe-bursting issues with the steam build-up in the line?

Yes, as powerkek said it, you can use simply the water as pressurant. Be just careful, state change impact temperature and evaporation cool down, with water it can be a problem. The advantage of Nitrogen is that it block state change and require only a little backup to reinject the Nitrogen pumped with the liquid back to the network.