Posted on 07/18/2013 2:06:47 PM PDT by thackney
5
LNG is not stored under any significant pressure.
Unless you have some serious insulation and/or some serious refrigeration,
Standard vehicle tanks like long haul trucking have insulation to allow 5 days without addition refrigeration or venting from boil off. I assume the aviation industry can handle similar requirements.
LNG is methane cooled to -260°F. Are you confusing it with LPG? LNG is not pressurized, just cooled. LNG will not ignite until after it is vaporized then diluted with air(oxygen).
False. Just as described in the article you linked, typical tanks have enough insulation to keep LNG without venting for about a week, regulations require 5 days.
LNG contained only 60% fuel value of the same weight of diesel.
LNG contains MORE energy per pound, but less per volume.
It costs $70,000 to convert a truck to LNG so it could cost a million dollars to convert a plane.
A million to convert. What a laugh. But in reality these would be built new for the fuel tanking, not converted.
Do you have any idea what the FAA requires for certification on aircraft. You fuel utopia will have to be crash tested on each model of tank. Jet engines will have to be rebuilt for gas fuel and re-certified for gas fuel. Each airstrip with a long runway will need a new cyro fuel service. The planes will have to be drained of fuel or have provisions for re cooling of fuel in emergencies and maintenance. This dream requires a whole new expensive system running parallel to the existing system. Who will pay for this pipe dream, tax payers? Airlines will not pay for this when we have more crude oil discoveries and more oil that was imagined a decade ago.
Air derivative jet engines have been used with natural gas fuel for decades. I've been on the design and construction team that used Rolls-Royce RB211s for compressor stations. That is the same Jet engine that Continental (now United) was using on their larger jets.
The planes will have to be drained of fuel or have provisions for re cooling of fuel in emergencies and maintenance.
Yes, if the plane engines haven't been run in 5 days, they will need to be connected to a vapor recover system, fuel removed or vented. Not a major cost or problem.
This dream requires a whole new expensive system running parallel to the existing system.
No, the planes would only need a single fuel system.
Who will pay for this pipe dream, tax payers?
It should be paid for only by the users. It has been done on trucks, trains, ships, etc already. This isn't a big leap like you suggest.
Nope it was LNG. Yes, LNG is “self refrigerated”, it cools when vented.
LNG or LPG will go bleve under the right circumstances. Cracking the container wide open will release a lot of vapor even as the temperature drops, and any vapor between LEL and UEL will burn. The flash point is -300 or so, so you don’t need to raise the temperature much to get ignitable vapor.
Cracking a container of Jet A does not release anywhere near as much vapor, and you have to heat it to +140F to get it to ignite. That’s considerably above ambient compared to LNG.
Bleve with high-boiling hydrocarbons does happen, that’s what just happened in Canada, but it’s much more frequent with LPG, LNG, propane, etc.
These days we have SERIOUS (and very light) insulation. Remember, the space shuttle tiles are 1980's technology. The science of insulating materials has advanced hugely from "way back then".
Today we have MANY much lighter and better insulating materials (see aerogels). So no, it will not "rapidly boil off". And given these circumstances I fail to see why wings can no longer be used to store fuel. I would guess that the insulated tankage would weigh no more than current ones.
You're mixing CNG properties with LNG. CNG is stored at high pressures (3500 psi). LNG is not. LNG is refrigerated, CNG is not.
And no, I don't think an on-board refrigeration system would be needed. Airports would do what they already do, have the capability on the back of a truck. Drive up, hook up, and cool down.
But given today's high efficiency insulating materials, I doubt that such would be necessary except for REALLY extended delays.
I think the regular jet fuel would be cheaper than going to a whole new system. The airlines are too competitive to spend the kind of money refitting planes and new airport equipment would required. With all the crude oil discoveries crude oil should be coming down in price making LNG less attractive.
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