On 2/14/2018 6:26 PM, Henry Spencer wrote:
On Wed, 14 Feb 2018, Randall Clague wrote:
When we first started with methane, we put some effort into using liquid nitrogen to liquefy natural gas from our municipal supply. We found that natural gas gets tarry as you cool it, and that it's easy to freeze it unintentionally. When we froze it, we were done for the day.
I wonder if that is at least partly due to impurities, both hydrocarbon (unsaturated hydrocarbons reportedly get *very* viscous down at the bottom of their liquid ranges) and non-hydrocarbon (notably the sulfur-compound "stenchant" put into municipal gas so you can smell it).
That is to say, it might not be an issue for relatively pure propane. But it's certainly something that would need checking before you relied on it. (And cheaper propane often has some propylene in it...)