To amplify a bit, LNG composition varies widely depending on the field
it came from. "Vehicle grade" LNG tends to be from wells naturally both
low-sulfur (don't recall the ppm) and relatively high CH4 fraction (98%
plus in our case IIRC). Your average LNG well delivers something with
considerably more sulfur and heavier hydrocarbons.
And if you need to know more than that about what you're using, you can
draw off samples and send them out for analysis as to how much ethane,
propane, etc is present - at the time it cost on the order of some
hundreds of bucks per sample.
Henry
On 4/4/2017 11:12 AM, Doug Jones wrote:
We ran the 5M15 on LNG obtained from the truck fueling facility at the
garbage dump in Palmdale. We bought an LNG tank that had been removed
from an LNG fueled truck, mounted it on a trailer, got an account with
the depot, and routinely sent a couple techs down to fill it up the day
before a test. Swipe a credit card, hook up the hose, push a couple
buttons. LNG has no odorants and we had no hint of any coking.
Doug Jones, Chief Test Engineer
XCOR Aerospace
1325 Sabovich
Mojave CA 93501
(661) 824-4714 x117
cell 661 313-0584
On 4/4/2017 10:11 AM, Brian Feeney wrote:
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).
As an aside Jeff Bezos said they were using Hydrostatic bearings on
the turbopumps for long life, cooled by the fuel and LOX appropriately
- no maintenance between firings.
Cheers
Brian Feeney
On Tue, Apr 4, 2017 at 12:56 PM, Rand Simberg <simberg@xxxxxxxxxxxxxxx
<mailto:simberg@xxxxxxxxxxxxxxx>> wrote:
Actually, my understanding is that the BE-4 runs on LNG.
On Tue, 2017-04-04 at 12:53 -0400, Brian Feeney wrote:
Both Blue Origin and Space X are using Methane in their new
engines currently under development.
Again both say they are shooting for very high reusability rates,
rapid turn around times measured in hours and 100's if not 1,000
cycles plus target in the case of Blue.
I assume they must be using a high purity form of methane as
described by Henry Spencer to reduce the chances of coking,
corrosion with the copper inner chamber...
Can one get a non stenchant form of purified methane in bulk and
or would they both have to purify it (remove Mercaptans, any
polymerizing compounds etc) after taking delivery. i.e. is it
legal, safe to road transport in bulk in a purified non odour form.
Cheers
Brian Feeney
On Tue, Apr 4, 2017 at 12:30 PM, Henry Spencer
<hspencer@xxxxxxxxxxxxx <mailto:hspencer@xxxxxxxxxxxxx>> wrote:
On Sun, 2 Apr 2017, Graham Sortino wrote:
Is there any general guidelines in terms of the temperature or
pressure at
which point coking in coolant channel occurs when using Jet-A
(ie. some kind
of max temp and/or pressure to avoid)?
Never heard of anybody looking into that, although it's not
something I've gone looking for. Possibly there might be
something to be found in studies of fuel stability in
high-supersonic and hypersonic aircraft (where friction heating
can get fuel in wing tanks pretty hot) -- not quite the same
problem, and often dealt with by using special fuels, but it
might offer some hints.
It would be tricky to get good numbers for something like Jet-A
because there's so much variation in its exact composition.
Henry
