[AR] Re: RP-1 (was Re: [LPL] IPA Effects on Copper)
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Tue, 4 Apr 2017 15:34:03 -0400 (EDT)
On Tue, 4 Apr 2017, Brian Feeney wrote:
Actually, my understanding is that the BE-4 runs on LNG.
That would be quite something in light of what we've been discussing.
Has anyone on the list used LNG in a regen engine from your local source
(i.e. no modifications to the LNG).
Remember, above all, that LNG is not a single standardized substance.
There are specs (plural!), but also variation within them. Somebody who's
buying the stuff by the kiloton, and is willing to pay a premium price if
necessary, will have a lot of say in what he gets. Smaller customers will
have to take what's in stock, which can vary depending on where they are,
time of year, phase of moon :-), etc. Individual favorable experiences
might not apply elsewhere.
Commercial LNG is normally pretty much sulfur-free, because sulfur is hard
on the liquefier machinery and so it has to be pretty thoroughly scrubbed
out first (and LNG is not a consumer product, much, so safety concerns are
reduced some). Do-it-yourself LNG, liquefied from consumer natural gas,
might be a different story -- most stenchants will freeze out, but maybe
not completely, YMMV.
As for things that will polymerize, could depend on where you are and
where your gas comes from. North American (and British) natural gas is
usually "lean", lower in heating value, which means close to straight
methane with not much in the way of heavier impurities, maybe just a bit
of ethane -- anything heavier has been removed to be sold separately.
Asian or European natural gas is usually "rich", and may well have things
like propane added (or not removed) to boost its heating value, so that
could be more of a concern (e.g. propane often comes with some propylene).
Vulnerability to coking might depend on details. The Aerojet
experimenters found that adding a bit of ethylene to their tech-grade
methane *didn't* cause classical coking -- not clear why.
... i.e. is it legal, safe to road transport in bulk in a purified non
odour form.
As above, if LNG is okay for road transport at all, it's probably okay
without stenchants, since it normally doesn't have any. (Propane might be
a different story, although I did recently see railroad tank cars whose
markings suggested non-stenchant propane -- they were marked as containing
LPG, with an obviously-more-recent addition of "non-odorized" or something
like that. Don't know whether this meant an actual change in contents or
just a more explicit warning label.)
Henry
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