Another PSA about relief valves: make sure they’re sized appropriately to handle how much gas is going to have to blow out to save your ass. If any water may be present (or liquid CO2) icing is a real problem and you should consider using two PRVs or a PRV and rupture disc.
Lastly: make sure you vent your relief devices! That gas has to go somewhere and unless your in a classified environment (in which case your relief has to be vented anyways) you don’t want that to be indoors
If there are minor leaks I start seeing them around 60 psi. And also some valves loosen up when frozen below 0 and can leak unless you adjust the packing.
Master graywolf once told me- go with the 12x12 collection, you wont regret it.
I prefer not to use tri clamps over 6” but I agree it’s good to give yourself room to grow. A custom collection vessel solves the larger clamp issue.
I understand that the large vessel cant take as much pressure- at the same time a large vessel is under less pressure unless you overfill it.
my 12x12 can hold 100 psi for a day, I havent tried testing it further becaue I dont think my hydrocarbons make that much pressure.
The short answer is: yes.
At a temperature of 110F (which is really too high of a temperature to operate at if you’d like to retain terps), the pressure of 100% n-Butane is 47psig (the g indicates what a gauge on a closed system would register).
Per ASME pressure vessel code, a closed vessel should be able to hold 1.3x its pressure rating meaning a 100psi system should withstand 130psig. Which is about 36% of what your max pressure should be.
There are, however, some caveats:
you should be aware that the addition of nitrogen to the system can lead to pressures above safe levels…this is ESPECIALLY true if you are using a pump—please do not use a hydrocarbon recovery pump to pump nitrogen…they are to compress LPGs ONLY.
Pressure tests should be conducted after each assembly/disassembly.
Utilize volume and weight to ensure you’re not overfilling your system. It is better that you don’t fill columns and definitely not solvent tanks to the top. Leave some room.
its the wrong thread but im about to use notrogen for the first time. Im confused. for example if I use nitrogen to push through crc then what I THINK I should do is = keep the collection cold and burp out the headspace to a safe area. Will this get all the nitrogen out? I have a propane iso butane mix so its tough to get it so cold that there is no pressure from the gas themselves.
The gas pressure will actually help push the nitrogen out of the headspace
so I havent done it yet but what I descrived should work?
That will work for the collection. Depending on your set up you may need to vent your tank or columns.
They don’t necessarily have to be cold if you’re venting to a safe area and don’t mind the loss of gas.
Edit: cold is definitely more ideal though, not recommending that people vent warm.
def gona vent tank the same way. Ill be using the nitrogen to push though a cooling coil into material. so are you saying that the nitrogen leaves first? Kinda like the propane is first to go in the mix due to higher pressure?
The gases will be mixed to a large extent. If you’re venting than you’re venting hydrocarbons and nitrogen.
Yes I can take a loss in gasses but you scared me about not letting the pump pump nitrogen- I am also just going from passive to active. I have done a couple dry runs just using mol sieve to clean up the gas but am about to try the real deal.
Dead wrong!!
Unless you over fill, volume of solvent is irrelevant. It is temp that defines pressure.
Yeah you’ll definitely take a solvent loss and throw off your gas blend that way but it can be done
it has to be done to push cold hydrocarbons right?
If you’re just using propane and butane the chart @TheGratefulPhil posted upthread will get you blend with just a thermometer and a temp probe.
If you’ve got isobutane in there you’ll have to find the Aussie Bush grub table I put up somewhere.
Yeah I have that chart in my screen shots for quick reference 