Yeah owned a few when they were real cheap. They use a pyro pressurization charge in each tank and pyro firing charges in the wand.
The charges were always extremely scarce, nearly unobtainium even when we had open weapons trade with the Chinese.
Small lots of the charges did come in. I had a few boxes up until maybe a decade ago, may still have an American military translation of an LPO Soviet era manual.
As a flame system they received high marks for reliability under extreme conditions and didn't require a charging station.
I fired one of mine up back in the early 90s a couple times, neat toy.
Nope, likely no go on converting them to a pressurized gas system, they were never designed for that.
Might be able to jury rig up CO2 feed with a larger paint ball bottle but you are still stuck on ignition.
Running on the straight fumes of old memory I recall Omega Weapons Systems out of AZ brought in the bulk of LPOs when he was up to his eyeballs buying surplus from the PLA. Bricklee Trading Ltd had them as well, probably sourced through Omega. The character I obtained my charges from back in the day was a Chinese gentleman based in Seattle, certain he's long dead.
You could check with Charlie Hobson, see if he has any ideas on putting a LPO back into use if he's still active.
I'm real cautious regarding flame guns, they are damn dangerous on both ends of the wand.
I wouldn't be the one to attempt to reverse engineer the pressure charges, ignition charges wouldn't be that bad to create though.
Knew a guy who trained with the LPO in the PLA, he stated they never had an issue with the pyro pressure charges igniting the payload and they used everything from diesel to fuel oil, kerosene, even gasoline with and without thickeners.
I'm still a bit uncomfortable with the entire concept.