Talk:Alleged Chemical Attack, April 7, 2018

At the UN meeting (video)(with Russian and the other proposed sessions combined) Nebenzya told that Russian experts went there but were unable to find evidence of attack (no poisonous samples, no bodies in the only hospital or the graveyard, no witness evidence. He invited OPCW to visit immedeately, tomorrow. After all that, some theater of absurd, Dutch and US rep blaming Russia for everything, baby crying and so on. I mean, one of the sides must be very badly lying, on purpose; quite sickening to listen all this Babylonian tower miscommunication  --20:13, 9 April 2018 (UTC)

'US wants UN vote' today --to fail and justify military strikes(talk) says Reuters. Brilliant plan. (Nikki Haley posterior shown out of the UN door with assistants in tow yesterday when Syrian rep got the floor. And she was talking babies photos right after Russian rep told that no traces of attack could be found). --Resup (talk) 04:25, 10 April 2018 (UTC)

Frost on Cl Cylinder ? Nah.
The usual suspects are now claiming the whiteish object in the roof hole 'on the day' is frost on a yellow cylinder.

This document gives some information



Reading in general on evaporation of liquids in cylinders, most heat is absorbed into the boiling liquid, not into the gaseous part and not where it exits the cylinder through a valve.

The position of the cylinder and presumed vent pointing into the room underneath show that the liquid in the cylinder would be at the the bottom of the cylinder. This will result in the liquid being expelled under pressure and not boiling inside the cylinder.

This results in two effects.


 * The liquid would boil outside the cylinder and presumably some distance from it. As a result the cylinder won't be cooled by heat boiling the chlorine inside the cylinder
 * There will be no gas expansion at the vent thus absorbing heat, so no cooling effect from gas coming out and expanding

There will inevitably be an argument that the chlorine in the cylinder is gas, not liquid. However:


 * Chlorine liquefies at 778kPa at room temperature see Chlorine Data That's about 112psi.
 * 112psi in a 40 litre container is naff all. When was the last time your air compressor tank frosted over when you hit the release valve?

Conclusion:


 * There would not have been frost formed if the cylinder contained only compressed chlorine gas - not liquid.
 * If the cylinder had liquid chlorine it would have been jetted out the exit hole and cooled elsewhere - so no frost or minimal frost on the cylinder
 * If the cylinder was leaking so slowly that there was significant boiling inside it, it would have taken hours and people would have had plenty of time to escape

--Charles Wood (talk) 20:38, 17 April 2018 (UTC)



Hi, interesting (in general abstract/knowledge sense), generally agree but maybe slightly trickier (below), do not have time to sort if out now (hopefully later), but in any case, it is quite irrelevant to the chemical attack situation, whether freezing tank or freezing green men from Mars, it's still a staged fake all the same, so kind of not worth it to put much effort in figuring another theory. On the content, what might be going on is, as you say, there is liquid at the bottom, gas on top, and they are in equilibrium, which means that pressure and temperature are related by Clausius-Clapeyron boiling pressure-temperature relation, P = P_o exp(-H_b /RT (1/T-1/T_0)), H_b specific boiling heat. As it leaks out and pressure tries to drop, it makes liquid above new lower boiling temperature, so just enough of it evaporates quickly to compensate and stay on Clausius-Clapeyron. Cooling occurs because (1) gas expands inside the tank as volume of liquid inside drops (2) whatever is needed to evaporate the liquid still inside to stay on the boiling curve; but as you say, escaping liquid evaporation does not contribute. Gas inside may be taken as ideal but the amount of gas is tricky as it is in equilibrium with (leaking out) liquid. It can be worked out but a bit messy and also not relevant, a fake is still a fake, before or after sorting this out. On practical side I guess it is like charging air conditioner, not like emptying air compressor. In charging AC, tank does freeze a bit at the bottom, I guess for the reasons above, as there is quite a lot of inside the tank evaporation in gas-liquid mix at equilibrium --Resup (talk) 07:11, 18 April 2018 (UTC)


 * The most suitable reference is BBQ propane cylinders. If run hard enough they cool down at the bottom where the liquid is evaporating - maybe even frosting but I've never seen it.
 * And the best test of the Smiggins theory is get a large propane cylinder, invert it, and open the valve. Lots of liquid propane on the ground and nil freezing of the cylinder. --Charles Wood (talk) 07:33, 18 April 2018 (UTC)