In the wake of the heated discussion in the media(and on this forum) about crude petroleum shipment by rail comes the possibility of Liquid Natural Gas transportation by rail:
http://www.reuters.com/article/2014/06/16/us-usa-railway-natgas-insight-idUSKBN0ER0D620140616
The article was written last Summer but I could not find any discussion of it so far on the Trains forum..
At least one US based cryogenic tank car manufacturer is working on LNG designs:
file:///C:/Users/jcarney/Downloads/R-PraMarketingLiterature14722936_LNG%20Railcars14722936%20(1).pdf
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
You might ask Norfolk Southern what they think of the idea. I seem to recall that a misadventure with LNG cars did a number on one of their yards a few decades back.
Bakken crude burns. LNG BLEVES!!*
*Boiling Liquid Explosive Vapor Explosion. Monster fireball and rolling stock parts headed for orbit.
I'm not concerned with Bakken crude passing through town. The individual LNG and propane cars in the nearby industrial area concern me. I don't even want to think about a LNG unit train.
Chuck
tomikawaTTBakken crude burns. LNG BLEVES!!*
That's funny. Just about every serious study I've seen since the '70s notes that there's minimal risk of an actual LNG BLEVE -- and that only if the carrier is colossally poorly designed.
A 'better' argument is that the heat release from a LNG pool fire is greater than that from an equivalent pool of gasoline. But that's after the fuel has been released to atmospheric pressure, and the cryo drops the ambient temperature so the expansion of the ignited gas cloud stays limited.
Chuck, I thought you were familiar with cryomethane in the USAF... ;-}
CNG -- now, that scares me. I don't like large-volume critical-mixture explosions.
LNG is commonly shipped in cryogenc tank truck trailers now anyway. I don't see how moving it by rail would necessarily be more dangerous. See for example this 2012 "white paper" article titled "Delivering LNG in Smaller Volumes" (5 pages, approx. 312 KB electronic file size in this 'PDF' format) from a Finnish company that builds such tanks (mostly small ship and industrial size, but it does mention trucks and containers):
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB4QFjAA&url=http%3A%2F%2Fwww.wartsila.com%2Ffile%2FWartsila%2F1278525949884a1267106724867-ID0112_E5_Delivering_LNG_in_smaller_volumes.pdf&ei=kHBwVJiALqO1sQSWj4HoDw&usg=AFQjCNE91Mmuym2jTwSaqSGpOyoN186gaQ&sig2=9iXJ6vGkwEogkObsDy4C5g&bvm=bv.80185997,d.cWc
LNG has been shipped (imported) by tankers for years, although less so since shale gas. IIRC they would stop all other shipping in Boston Harbor when the LNG tanker came in.
Euclid What is the current status of shipping LNG by rail? To what extent is it limited and why?
http://www.railwayage.com/index.php/mechanical/locomotives/experts-weigh-in-on-lng.html
I guess this quote is the answer to my question above:
“For example, under current FEMA rules, LNG is not permitted to move by rail, unless there is an FRA waiver.”
So I conclude that, yes, getting the public to accept the safety risk of LNG by rail, in unit train production, would be impossible after the safety issue that has developed around crude by rail. However, some believe that the oil by rail safety issue is largely a drummed up pretext to thwart the use of fossil fuels. Thus, LNG would be far more acceptable than the politically correct objections to oil. So for LNG, there may be no safety issue working against it.
However, according to the article in the OP, what is driving up the LNG supply is oil development. So the climate change acceptability of LNG will be offset by the climate change objection to oil because the two are linked in production.
EuclidHere is an article on development to use LNG as locomotive fuel: http://www.railwayage.com/index.php/mechanical/locomotives/experts-weigh-in-on-lng.html
A somewhat better reference to start with might be this .pdf from Wyoming, which contains some technical detail. Interestingly, this seems to take for granted that rail approval for LNG transport will be secured:
"Guidelines for the transportation of LNG by rail are currently being established in partnership with the American Railroad’s[sic; AAR] Tank Car Committee and the Liquefied Natural Gas Technical Advisory Group."
Discussion of small-scale liquefaction starts roughly on p.103. I think, however, that a much more likely approach would be to build out a larger liquefaction plant close to service terminal areas -- the report notes this:
" ... the capital cost of such liquefaction must now be at least partially covered by the new LNG user, if they intend to own and operate the LNG plant; or another vendor must deal with those capital costs and potentially find multiple LNG users nearby to provide the necessary revenuestream to payback those costs. As interest in natural gas continues to grow, finding a financial lender to back a new LNG plant may be a viable option for larger operations. An increasing number of financial institutions are enteringthe market to support LNG projects of all sizes, due to low commodity costs and projections of increased natural gas production and consumption."
I would think that many railroad service points might have 'brownfield' areas that might provide attractive sites for liquefaction facilities...
In any case, as already noted, a 'likely' short-term alternative will be to use trucks to handle refueling delivery, perhaps coordinating with crew-change stops. That will remain a highly preferred strategy until a high percentage of locomotives are converted -- which I don't think will happen for at least a few years.
The Wyoming link is about local in-state production and use of LNG for mine trucks, drilling rigs, locos, etc. The study states:
"This report concludes it
is unlikely that a large centralized LNG production plant will
be the best approach to supply the state’s estimated LNG
demand of 509,000 GPD. This is primarily due to 1) the risks
developers would face in building large-scale LNG plants in
tandem with a one-to-two decade phased LNG market, and 2)
the higher costs of LNG for end users if it is transported over
distances exceeding about 250 miles."
This indicates that the cost savings of using LNG as an alternative to diesel, diminishes with the transport distance. While transporting crude-by-rail is somewhat more expensive than by pipeline, transporting natural gas as LNG-by-rail is way more expensive than transporting natural gas as gas thru a pipeline. As indicated in the OP's referenced link, it is being considered in the Bakken and other remote fields that are yet under-served by pipeline. Shipping gas as LNG-by-rail is the conservation minded alternative to flaring the gas that is produced along with the oil. It will be a niche market until gas pipelines catch up to production. It has even less economic potential than CBR.
I should probably add that I was discussing the shipping of LNG in the context of using it as a locomotive fuel, as an alternative to having it trucked either to servicing points or to consists. I don't particularly think there is much market for long-distance shipping of cryomethane in a necessary purpose-built fleet of dewar cars.
Something I'd like to find a resource for: what is the market for the heavier fractions (butane, propane, etc.) that are separated from the cryomethane as it is liquefied?
Could LNG be combined with frozen good shipments? Less damage then in a spill.........
(In the same train. Not the same car. Duh!)
LensCapOn Could LNG be combined with frozen good shipments? Less damage then in a spill......... (In the same train. Not the same car. Duh!)
I cannot speak to the use of LNG as a refrigerant intransport of frozen food, but for years there has been truck shipments of very perishible medical supplies, in van trtucks and trailers utilizing 'blanketing' of the cargo from an on board supply of liquid nitrogen that is vaporized to freeze the cargo.
Some consumer products are now using packaging that add to its shelf life with nitrogen blanketing. My guess is that using LNG as a coolant would possibly effect not only taste, but as it was gassed off, a combustion problem.
tomikawaTT You might ask Norfolk Southern what they think of the idea. I seem to recall that a misadventure with LNG cars did a number on one of their yards a few decades back. Bakken crude burns. LNG BLEVES!!* *Boiling Liquid Explosive Vapor Explosion. Monster fireball and rolling stock parts headed for orbit. I'm not concerned with Bakken crude passing through town. The individual LNG and propane cars in the nearby industrial area concern me. I don't even want to think about a LNG unit train. Chuck
Under normal conditions Natural Gas in liquid form will not cause a BLEVE:
http://www.netl.doe.gov/publications/proceedings/02/ngt/quillen.pdf
However,LNG accidents can trigger very intense fires. I'm certainly not saying it's not a hazardous commodity..
I do bet though that if any of the U.S railroads starts transporting LNG in large quantities there will be many stories in the media repeating the BLEVE claim. People seem to think LNG tankers are floting bombs so trains will be viewed as rolling ones....
A BLEVE (Boiling Liquid Expanding Vapor Explosion) can occur in a 55 gallon drum.
Generally, a BLEVE occurs when fire impinges directly on the vapor space of a closed vessel. The metal weakens at the point of impingement, meanwhile the pressure inside the container rises. At some point, the metal fails and the liquid is released.
If the liquid is flammable (a container of water could actually BLEVE), it obviously ignites and we're off to the races.
Half of one of the cars that BLEVE'd at Oneonta travelled some 3000 feet, stopping only when it ran into a riverbank. Usually one half of the tank remains intact and takes off like a rocket, while the other flattens out and stays more or less in place.
Because of the resulting improvements to LPG tankers, we don't hear about incidents like Kingman, Crescent City, or Oneonta much any more, yet LPG is moved all across the country on a daily basis.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Tree68 (Larry) said[snipped] "...Half of one of the cars that BLEVE'd at Oneonta travelled some 3000 feet, stopping only when it ran into a riverbank. Usually one half of the tank remains intact and takes off like a rocket, while the other flattens out and stays more or less in place.
Because of the resulting improvements to LPG tankers, we don't hear about incidents like Kingman, Crescent City, or Oneonta much any more, yet LPG is moved all across the country on a daily basis..." [snip]
Larry and others : You might find the following linked NTSB Report of some interest.
https://s3.amazonaws.com/omeka-net/361/archive/files/981afb3a79122f40628455a9ba0c7370.pdf?AWSAccessKeyId=AKIAI3ATG3OSQLO5HGKA&Expires=1416914318&Signature=61%2FvgiO8oVrOk0Hzcy0T%2FYe5oOU%3D
This is the report of the accident at Waverly, Tenn on Feb. 22, 1978 on L&NRR Train 584 and the subsequent BLEVE of an LPG tank car. Kiled were 16 and 57 injured. 6 of the killed were Fire Service. 7 reilroad and Contractor employees were killed, and 19 sustained pretty serious injuries.
I happened to be in the area when the wreck occured, and left before the explosions occured. I also was back several days after the 23 Feb explosion had happened... The photos do not really do justice to the scene.
carnej1 However,LNG accidents can trigger very intense fires. I'm certainly not saying it's not a hazardous commodity..
The mother of one of my very long term friends was in Cleveland when the LNG accident happened during WW2. If she had been one bock closer, she would not have survived. Part of the problem was that the LNG from the leaking tanks flowed into the sewers, so the "cloud" of flammable gas had a chance to spread before it found an ignition source, which then led to a fuel air explosion.
One thing that helps a bit with methane is that it has a very high ignition temperature, IIRC, the equivalent octane rating (really performance number) of methane is 130. Another aspect that reduces the risk a bit is that ambient temperature methane is lighter than air and disperses rapidly.
- Erik
LPG and LNG are very, very different materials. LPG is kept liquefied by pressure alone, and is normally transported at ambient temperature; it BLEVEs quite nicely under a variety of common railroad-accident conditions, but that has nothing to do with what LNG would do under similar conditions. Butane as in lighters, propane as in torch cylinders...
The heat content of a given volume of LPG is considerably higher (about 2.5 times) than that for LNG, so a critical-mixture explosion involves that much more fun.
Cleveland was indeed an example showing difficulties with cryomethane: the material ran down into the sewer, and did not boil off immediately, leading to repeated problems both with pool fires and with critical-mixture explosions when the correct proportion of gas and air developed in the enclosed spaces of the sewer system. I doubt that this situation would recur in most LNG scenarii, even if the tank vessel were catastrophically breached to release a large volume of cryo material -- the likely 'accident' would be a pool fire, as previously indicated, with no tendency to form a detonable mixture.
Overmod ... Something I'd like to find a resource for: what is the market for the heavier fractions (butane, propane, etc.) that are separated from the cryomethane as it is liquefied?
...
Butane is mainly used (90%) in blending with gasoline.
http://pubchem.ncbi.nlm.nih.gov/compound/butane
About half of propane production is used in LPG for heating, cooking, etc, and much of the other half is used in the petrochemical industry.
http://pubchem.ncbi.nlm.nih.gov/compound/propane
The other component seperated at gas plants is ethane, which is mainly used in the chemical industry.
It's a cold liquid, behaving much like liquid nitrogen (although not as cold). Has relatively low viscosity, so it flows from breaches and seeks the lowest level fairly readily. Both the liquid and the gas cloud evolving from it are made visible as moisture in the air changes state. Liquid methane changes state to gas, relatively smoothly and more from its surface than via nucleate boiling; gas is lighter than air at equivalent temperature and rises and dissipates much as any gas leak would -- it is cold, just as CNG is after release from a breach, but doesn't mix (and carburete) as readily since the turbulent mixing caused by pressure release from compressed pressure is absent.
One other detail: there is little or no odor to cryomethane, as the mercaptans etc. that are odorants in typical 'gas' freeze out long before methane. That means you need good and sensitive methane detectors, particularly at accident sites.
Overmod ... Liquid methane changes state to gas, relatively smoothly and more from its surface than via nucleate boiling; gas is lighter than air at equivalent temperature and rises and dissipates much as any gas leak would -- it is cold, just as CNG is after release from a breach, but doesn't mix (and carburete) as readily since the turbulent mixing caused by pressure release from compressed pressure is absent. ...
... Liquid methane changes state to gas, relatively smoothly and more from its surface than via nucleate boiling; gas is lighter than air at equivalent temperature and rises and dissipates much as any gas leak would -- it is cold, just as CNG is after release from a breach, but doesn't mix (and carburete) as readily since the turbulent mixing caused by pressure release from compressed pressure is absent.
"gas is lighter than air at equivalent temperature" The thing is that methane gas evolving from LNG has a temperature about half way to absolute zero from ambient (air) temperature. Since methane is about half the molecular weight of air, the temperature difference between the air and gas, would leave them at about the same density. (IIRC my college chemistry)
MidlandMike Overmod ... Liquid methane changes state to gas, relatively smoothly and more from its surface than via nucleate boiling; gas is lighter than air at equivalent temperature and rises and dissipates much as any gas leak would -- it is cold, just as CNG is after release from a breach, but doesn't mix (and carburete) as readily since the turbulent mixing caused by pressure release from compressed pressure is absent. ... "gas is lighter than air at equivalent temperature" The thing is that methane gas evolving from LNG has a temperature about half way to absolute zero from ambient (air) temperature. Since methane is about half the molecular weight of air, the temperature difference between the air and gas, would leave them at about the same density. (IIRC my college chemistry)
Not claiming to be a pool-fire expert here -- but look at your college physics, too. As soon as a molecule of CH4 at cryo temp has reached the gas phase, it mixes with (ambient) air following gas kinetics, and therefore will heat far more rapidly than the underlying pool, becoming gradually lighter as it does so, but as you note, remaining substantially denser than the surrounding atmosphere for some time. That is part of the reason why LNG pool fires can be so intense - there is a 'rich mixture' proportion of fuel in the gas state close to the pool, and should there be ignition of the gas plume at any point, the heat release will almost certainly amplify the turbulent mixing of that plume as well as the rate of phase change from liquid to gas at the pool surface.
For those who were counting molecular weights and wondering why CH4 is about half the atomic weight of air, remember that both major constituent gases in the atmosphere are diatomic -- N2 and O2.
I can see two possible reasons why people might oppose adding LNG trains to the railroads:
1) Adding LNG would simply add more fire and explosion hazard to rail traffic.
2) Adding LNG would add fire and explosion hazard that is more severe and more dangerous than the fire and explosion hazard of crude oil.
EuclidCertainly reason #1 is true. But is reason #2 true or false?
I don't think there's a 'straight' answer to that, any more than there's a noncomplex answer to why some railroads say quiet zone crossings are less safe than those where horns are sounded.
Bakken crude-oil fires vs. those for some other types of crude already show a great difference. I think that's already been covered to death in the various Lac Megantic beatdowns.
LNG probably has less propensity to prompt ignition in a typical railroad accident: it's inside an armored Dewar, comes out as a cold liquid, and as noted its vapor is initially very cold and a substantial mass of cold vapor has to be brought up to transition temperature before combustion reactions will be sustained in the gas plume. On the other hand, once that combustion is initiated above a gas plume the fire will be hotter, although still non-explosive.
The worry I have with natural-gas fires in general is if they occur in a confined space, or if the LNG liquid or dense vapor flows into confined spaces (as in part of the accident in Cleveland and is exposed to an ignition source. Critical-mixture combustion produces great heat release in a short period of time, and when the mixture is confined the flame-front propagation easily goes from normal burning to detonation. See this reference from Combustion and Flame, or this one which describes some of the parameters, for example (there are many other references). Midland Mike can take over to describe how the vapor from various crudes compares.
In any case, there is comparatively little likelihood that the capital needed to construct long trains of insulated Dewars for LNG 'service' would be used for that purpose instead of building better and safer oil trains. But that's a whole nother thread.
EDIT: I give up on getting this Bangalore software to make that first link live: it's www.dtic.mil/get-tr-doc/pdf?AD=ADA520957
Here is an introductory reference for unconstrained gas clouds.
Listen to Mike about this. It seems to me that you're continuing to assume incorrectly.
The problem at Lac Megantic was due to explosions and then combustion of hydrocarbons at ambient temperature. A similar incident with cryomethane would have resulted in flash-freezing an extensive area, with some likelihood of flash gas fires (probably fairly quickly extinguished due to local lean conditions) until the pool of cryo material began heating up -- likewise, most sources of ignition from the accident itself will be rapidly chilled below the temperature they would serve as ignition sources for a rich enough gas cloud.
I would assume that a fairly large number of dewar tankers would be damaged enough to leak patently, in an accident with the force of what happened at Lac Megantic, and I would be unsurprised if the released cryomethane did not cause damage to some other cars. On the other hand, let me repeat that the likelihood of an explosion from cryomethane is extremely, EXTREMELY unlikely... do you not like to read the references I provided?
The risk is of late ignition, and starting a pool fire. That will rapidly escalate to a situation where reliable flameholding for any other pools will exist, and you will have a hot, perhaps disseminated fire until the gas has boiled off. That may be enough for many people to dislike the idea of bulk shipment of LNG in unit trains; indeed, it's enough for me not to like the idea of bulk shipment of LNG in unit trains or blocks. But you need to get your reasons straight, and not keep arguing about the wrong ones.
One other difference between a petroleum fire and an LNG fire is that there are almost no molecules with carbon-carbon bonds in LNG. Without the C-C bonds, there is much less soot produced and the flame emits far less infrared radiation. The downside is the flames are harder to see.
Someone had posted a video on YouTube of an open air natural gas "explosion" (deflagration)- looked more like a very strong gust of wind than a detonation wave. Looked like the tree, poles and buildings got a minor scorching.
Keep in mind that the high pressure gas lines occasionally get punctured or burst. A recent exmple of the latter is San Bruno, California.
P.S. There is a big difference between deflagration and detonation. In a gasolene engine, deflagration is normal combustion, detonation is what causes knocking. The detonation results from the gas/air mixture being confined under great pressure.
WizlishI would assume that a fairly large number of dewar tankers would be damaged enough to leak patently, in an accident with the force of what happened at Lac Megantic, and I would be unsurprised if the released cryomethane did not cause damage to some other cars. On the other hand, let me repeat that the likelihood of an explosion from cryomethane is extremely, EXTREMELY unlikely... do you not like to read the references I provided?
For there to be an 'explosion magnitude' at all, there first has to be an explosion. Which is one of the points you continue obdurately to maintain. Read my lips: there are no explosions in LNG accidents, for purposes of this discussion.
Find me a reference for LNG cars ... mind you, not LPG cars ... being 'tossed a half mile or more'.
EuclidI suspect that the potential for explosion magnitude in an LNG fire involving leaking tank cars would be much greater than in a Bakken oil fire involving leaking tank cars.” I was not referring to the likelihood of an explosion occurring. I was referring to size of the explosion if one does occur.
I think a better question would be the size (and characteristics) of the fire when one occurs. This is probably the chief concern in a LNG accident. If the intensity of a LNG pool fire is substantially greater than a gasoline pool fire, I'd expect it to be greater still than a crude-oil pool fire ... I'd expect it to burn out sooner than a crude-oil fire, though.
A secondary question would be whether the higher pool-fire intensity would augment secondary damage to other cars, or chemicals contained in other cars, involved in an accident or derailment.
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