Rule Allows Natural Gas Transport by Rail in Dense Areas | Hacker News Reader

Rule Allows Natural Gas Transport by Rail in Dense Areas

npr.org

45 pointspseudolus61 comments

Time to air one of my most controversial opinions: I think transporting LNG by train is good. Hear me out.

When you build a pipeline, it's good for exactly one thing. An LNG pipeline won't do for anything else, not even other types of oil products. But building a railroad on the other hand, that's good for just about anything from transporting bulk grain to truck frames to solid rocket motors. Even though they built the original rail network 150+ years ago, that doesn't define the limits of what it can be used for today (other than the physical dimensions of the carriage etc). If we stop shipping oil by rail we can just build new rail cars and ship other stuff.

Obviously we have to consider safety. There are serious drawbacks of both ways to transport LNG, it's just inherently dangerous. Many people remember Lac Maganetic a few years ago, where a series of technical failures caused a high speed derailment that devastated a small town in rural Quebec. Many also remember the poorly maintained pipelines all over the world that dribble oil into the ground water 24 hours a day. The difference is that trains are comparatively very cheap and easy to inspect and retrofit with sensors. Rail transport is very visible when it goes wrong, but pipelines are far away and far under ground, most of the time buried beneath the 'under class'.

>When you build a pipeline, it's good for exactly one thing. An LNG pipeline won't do for anything else, not even other types of oil products. But building a railroad on the other hand, that's good for just about anything from transporting bulk grain to truck frames to solid rocket motors.

But doesn't that only make sense if there's going to be demand in the near future? Unused rail lines get abandoned all the time because they have maintenance costs, so it's not like we can build it, stop using it, and then resume using it a few decades later when demand picks up.

Those aren't the kind that are abandoned.

The kind to carry natural gas goes from A to B. The ones that are typically abandoned go from B to hamlet-near-B, or to factory-near-B, or were obsoleted due to a change in the network.

I see all three where I live. A new express route was built and bypasses some stations, so fewer trains stop at those stations, which makes local connections to those stations less valuable, and some X-to-hamlet tracks will probably be closed in the end. A new tunnel is being built and when it's done freight traffic will be routed differently than it is now, and it seems likely that one old route will be closed.

A random person being scared of something near their home does not make it actually dangerous. LNG doesn't explode like in the movies, it needs to vaporize and mix with oxygen to burn. A leak in an enclosed space can pose an explosion risk, but that's not an issue for a rail car sitting outside. Boiloff can potentially cause a tank to rupture, but this is easily prevented with a pressure release valve. If there is a leak, there is of course a fire hazard, but such a hazard is no worse than the leak of an oil tank. In fact, where an oil leak could potentially allow a large amount of fuel to pool up creating an explosive hazard prior to ignition, natural gas will mostly dissipate harmlessly prior to ignition. LNG transport is generally safer than crude oil transport, and a crude oil spill has much worse environmental effects. If you are comfortable with oil being transported through densely populated areas, you should be fine with this.

The problem isn’t a train with a single car of LNG, it’s a derailment of a train carrying mostly LNG. Trains of Oil, LNG, or other flammable liquid can become a major hazard in ways that a train full of say lumber isn’t.

Forty-two people were confirmed dead, with five more missing and presumed dead.[3] More than 30 buildings in the town's centre, roughly half of the downtown area, were destroyed,[2][4] and all but three of the thirty-nine remaining downtown buildings had to be demolished due to petroleum contamination of the townsite. https://en.wikipedia.org/wiki/Lac-Mégantic_rail_disaster

Yeah, but we already have trains of flammable liquid, and most are far more dangerous than LNG. Had a LNG train been involved in Lac-Mégantic there would have been no flaming tsunami of oil nor any petroleum contamination.

Latent heat of vaporization means huge quantities of LNG stay liquid for plenty long enough to get a flaming tsunami. Your not going to end up with petroleum contamination, but in terms of loss of life their about equally dangerous.

Anyway rail transport of oil through populated areas is also a major risk. Which is why it’s also banned in some places.

If you had a tsunami of LNG it would be more likely to freeze you than burn you. However the latent heat of vaporization for LNG is very low, it will vaporize quickly as it spreads out, unlike crude oil. You certainly won't get a flaming tsunami - you can actually extinguish a flame in LNG.

Transport of oil through populated areas is quite common. Local governments that have restricted its transport are welcome to do the same for LNG.

Latent heat of vaporization of LNG is 512 kJ/kg vs 2257 kJ/kg for water. Which is basically irrelevant when your talking into the million’s of kg of the stuff.

Do some math and even just a single 35,000 gallon tanker load is going to flow around like a liquid for quite some time.

3 kg of dry dirt at 20 deg C has enough energy to vaporize a kg of LNG (it takes slightly less concrete). Assuming on the timescales involved it can come into thermal contact with the top inch of soil, all the LNG from that tanker should dissipate once it spreads over a surface of 3000 m^2, or about 60% of the area a football field. It vaporizes faster when you take into account other sources of heat like the air, and way faster if you light it on fire. At most it'll be on the ground for a few minutes, but for a real spill it could be just seconds.

Sure, if it ended up in a nice flat cornfield somewhere then no problem, but the urban landscape is designed to channel ran. Thus it’s more a question of dispersal not duration.

Let’s say 10 tanker cars so 350,000 gallons or 560,000kg are spread down a water channel at the side of a street at 15mph. At 4 minutes their already covering 1 mile which easily takes them out of most towns making longer durations largely meaningless. If the channel is V shaped with a depth of 2 feet and a width of 10 feet. That only adds up to ~4,5000 square meters, and by your calculations most of it should still be there.

It doesn’t last as long if it’s on fire, but there’s going to be an air gap of unmixed natural gas over a likely several feel thick channel of LNG. So even then it’s going to take a while to burn off meanwhile the wave of fire is destroying everything around it.

10 tanker cars all instantaneously emptying directly into a 2 feet deep and 10 feet wide v shaped channel at the same point is not at all realistic. For starters, your V shaped channel is perfectly full when the LNG is spread out over a mile - over the preceding 4 minutes the LNG was spilling over the side of the channel onto the surrounding flat ground, dramatically increasing the amount of ambient heat it would have absorbed.

In a real scenario, the cars are going to be spread out over an area, their ruptures will be relatively small orifices that the fluid must flow through, it's going to spill out rapidly in all directions from that point, any area where a train is passing through is going to be decently wide and flat, worst case scenario probably a 50 foot wide street.

You can look up pictures of derailed tanker cars, for example [0], and see the area where the liquid spills over. By the time the contents of a tanker car have spread over an area of 1 acre, the fluid is only 1in deep, even if none of it vaporizes it's limited in how far it can meaningfully spread. The spill of a cryogenic fluid will by necessity cover less area. As you can see, the spill of 322,000 gallons of flammable liquid affects an area comparable to that threatened by the derailed train cars themselves. That fire lasted 36 hours, wouldn't it be great if all the fuel evaporated in 36 minutes?

[0] https://www.progressiverailroading.com/federal_legislation_r...

That sounds more like an argument against allowing rail transport of petroleum rather than an argument for allowing rail transport of LNG.

It very well could be if you don't feel the benefits outweigh the risks. But it's dumb to be fine with rail transport of petroleum and not LNG.

Exactly! And none of that would happen with LNG because natural gas is lighter than air, it would all rapidly rise into the sky and make a very pretty, and harmless, fire.

And speaking of lumber: https://bangordailynews.com/2020/07/29/news/a-scene-from-hel... (I need a better link, but basically the cars with hazardous material did not leak, and the fire was from lumber.)

Surprise surprise, Lumber is actually more dangerous than LNG! Because none of that would have happened with LNG. With LNG it all dissipates very fast.

https://en.m.wikipedia.org/wiki/Viareggio_train_derailment

32 dead because of derailment of LPG transporting train. Is the hazard posed by LPG much different to LNG?

Petroleum gas is heavier than air so it stays at ground level for an extended period of time, natural gas is lighter than air so it is dispersed quickly. The gasses in petroleum gas also have significantly lower ignition temperatures.

Yes. Propane is heavier than air, so it sits on the ground and just burns and burns.

LNG rises up into the air and is gone.

Would a crash be sufficient to cause a sudden aerosolization of the lng?

It seems to me that it could, but I am not an expert. Natural gas has a smell added because it has historically exploded...

> If you are comfortable with oil being transported through densely populated areas, you should be fine with this.

What if I'm not comfortable moving crude but train?

It's not enough to just aerosolize the LNG, it needs to mix with air in a rather narrow fuel-air ratio of 5-15% to burn. Further the flame front speed of methane in open air is only 4 mph - it won't explode, though as the flame front spreads it might kind of look like an explosion (think about what it looks like when you light a gas stove or grill). Such a fireball can potentially ignite things in close proximity, but there won't be a pressure wave that damages structures, so you can't have a situation where one tank 'exploding' causes other tanks to explode, though in a crash it's easily possible multiple tanks are damaged.

Natural gas is an explosion hazard in enclosed spaces. If you walk into your house and smell gas, that's very dangerous. Note also that even if there is no explosion hazard, fire is still dangerous.

If you are uncomfortable with rail transport of crude, that's a perfectly legitimate stance to take. Honestly, transporting any flammable substance (and many non-flammable ones as well) does pose risks. If you know the risks and benefits and think the former outweigh the latter, let people and especially your representatives in government know. However, society generally seems to accept rail transport of oil and similar chemicals, so outrage over the transport of a less dangerous substance seems like it would be more likely to come from a place of ignorance than rational analysis.

Your statements do not seem to be consistent with those in the article.

> Ray Mentzer, a chemical engineer at Purdue University, spent his career working on LNG projects for Exxon Mobil. He says the specially designed containers that transport hydrocarbons have a good safety record. But he says transporting the gas through densely populated areas increases the risk if there's a leak.

> "It's not flammable until it's vaporized, but it's going to be vaporized pretty darn quickly and then it's going to seek an ignition source," he says. "Believe me, it will find an ignition source pretty darn readily."

I will also note that those train tracks in the town in the photos had a derailment only a few years back. I am familiar with the area and know people who live there.

https://response.restoration.noaa.gov/about/media/train-dera...

There is no inconsistency. Natural gas is most certainly flammable once it's vaporized (it would be a very poor fuel if it wasn't), but there's a big difference between something being flammable and something being explosive. If you have a big leaking tank, it is very likely that it will catch fire, and no one really wants a big raging fire in a residential area, but that fire will only burn at the leak where fuel and air are mixing. It's very difficult out in the open to form cloud of natural gas and air with a uniform mixture such that it can all burn at the same time, and even then the flame front is too slow to cause a damaging explosion.

I would also note that the engineer's use of informal language here is clearly alarmist.

>Would a crash be sufficient to cause a sudden aerosolization of the lng?

Well yes, but actually no.

You can't get a freight train up to the kind of speed you need to create an "instantly dump the contents of the pressure vessel" type crash without creating a "slowly vent the contents out" type crash first.

You would need to use a bomb to rupture a pressure vessel to get the kind of fuel/air mix you need for an explosion or fireball. Fuel-air explosives operate in this manner. But they are devices with countless engineering man-hours spent making them actually work and fairly precise manufacturing. Parking ye ol' Winnebago (or Penske, if you're a history buff) beside the tracks and waiting for the train to go by is not going to be a very productive approach. Look at people blowing up propane tanks on YouTube. At best they get a fireball.

I'd much rather have nat-gas wafting up and away rather than crude oil, propane, or some other volatile that sits at ground level.

You get real differences of scale which makes smaller models inconsistent with what happens in a train derailment. Lac-Mégantic rail disaster for example had some serious explosions from oil.

According to the Wikipedia article there was much destruction, but... that happened when the oil flowed where it shouldn't and then burned in places where one really doesn't want it to burn.

Lighter-than-air gas is crucially different. If you let that leak out it won't flow downhill through the city, it'll go straight up. Of course you can argue that gas is dangerous, but not by example of an accident where most of the flammable material flowed away (and caused harm elsewhere) instead of either burning or exploding at the site.

LNG isn’t a gas, it’s a cryogenic liquid like liquid nitrogen except flammable. If we are talking say 100+ DOT-111 tank car‘s that’s 3,450,000+ gallons which isn’t going to simply fly into the air instantly. The phase change from liquid to has takes significant energy at the scale which takes time.

Again it’s a question of scale, you don’t think of say molasses as fast moving liquid but increase the scale to 2.3 million gallons and you can be talking about a 25 foot tall 35 mph wave. https://en.wikipedia.org/wiki/Great_Molasses_Flood

AIUI it's not flammable. It is flammable when mixed with air in the right proportion, but if it's mixed with air it is a gas and rises straight up, rather than flow as a wave across the landscape.

You can't have your cake and eat it.

Again small scale vs large scale. If your talking a square foot of the stuff then it’s going to rise like your suggesting. Cover a few acres in LNG you get complex boundary layer interactions and giant swirls of natural gas mixed with air.

Read up on how you can get temperature inversion layers in the atmosphere. In your model that kind of effect shouldn’t happen, but actual fluid dynamics gets complicated.

Explain how you get spontaneous combustion in the spots where the mixture is right.

Or were you thinking about transporting LNG together with something that that would help start a fire?

Train crashes have plentiful ignition sources as metal scrapes across metal. Oddly enough it’s surprisingly common for train crashes to result in fires ex: https://youtu.be/vww5V-xmtzs or https://baltimore.cbslocal.com/2016/07/06/recent-derailments... or the original disaster I mentioned.

At which point those secondary fires can easily ignite the literal pools on LNG being described.

I've thought about this a few times now.

Would you describe this as a noticeable risk compared to driving around in a car, in urban traffic, with gasoline? Or are you comparing it rather to an alternative that more or less avoids transport of LNG?

It could. But so could a crash of a truck or a train carrying any type of liquid/gaseous fuel (e.g. truck carrying the gas to your local gas station). The article talk about LNG requiring thicker tanks than ethylene and ethane, both of which could also 100% explode if in a wreck.

I think the worry is that the volume of shipments for LNG would be much higher, and hence the probability of something happening is higher. A singular shipment of LNG would be no worse than a single shipment of car gas.

Natural gas is lighter than air.

Any such aerosolization would rapidly go up into the sky.

It would make a fire, but not a disaster.

A Boiling liquid expanding vapor explosion (BLEVE) "blev-ee" is what I'd be worried about. Not for an explosion causing damage via shrapnel but from the radiant heat which can scorch things a kilometre away.

Here is a PDF with seems to have the longest url I've ever seen: https://pdf.sciencedirectassets.com/278653/1-s2.0-S187770581...

Disasters involving the transportation of fuel are not merely hypothetical or historically remote. The 2013 Lac-Megantic rail disaster led to 47 deaths and destroyed a small town [0].

[0] https://en.wikipedia.org/wiki/Lac-M%C3%A9gantic_rail_disaste...

This is why I never understood the intense Dakota Access Pipeline protests. Pipelines are much safer and better for the environment than shipping by rail. Shutting down the pipeline won't make the drilling stop, it will just make things worse for the environment and raise the cost of gas/oil

Yeah that was a bit of a head scratcher to me as well- I consider myself to be quite "green" in my political views, and I could not really grasp why this was picked up as an issue to champion for environmental rights- and why it even became such a political football. Pipelines are far superior in just about every way, and cheaper to boot- there isn't even a cost component like there is against the argument for nuclear (another head scratching issue to me).

It's one thing to make a case that this is infringing on their property rights, and that may have been a true and valid concern, but for it to get coopted as an environmental cause, was just strange and made environmental advocacy as a whole look bad IMHO.

The protest for Dakota isn't about the pipeline, it's about where the pipeline goes. Would you be okay with a pipeline going through your house?

Also pipelines are usually taking the human element out. When an oil train derails, you know about it. When there's a hole in a pipeline, it can take days for anyone to notice.

The route of the Dakota pipeline was along the exact path of an existing pipeline.

The real reason for the protests was that the tribe was NOT paid off because the pipeline CIRCUMVENTED their reserve.

Energy Transfer Partners (aka Sunoco) are pulling similar crap in Pennsylvania. Through or under dense housing, shopping malls, tearing up little league fields, occupying rights-of-way for years on end with drilling machines. They've already ruined many aquifers, poisoned a drinking reservoir, caused sink holes, even damaged their own nearby pipelines. All this before the thing gets pressurized with propane, ethane and butane. They subvert legislatures using public utility classification, eminent domain anything they want, and then bully anyone observing. Then they play the national security card for anyone asking about a disaster plan or blast radius.

There must be enormous profit here for such enormous public harm.

Marsh Creek lake: https://stateimpact.npr.org/pennsylvania/2020/08/11/mariner-...

Backfires? https://whyy.org/articles/sunoco-says-mariner-east-2-system-...

Criminal investigation: https://www.nbcphiladelphia.com/news/politics/chester-county...

Secrecy protection: https://www.spotlightpa.org/news/2020/12/mariner-east-pipeli...

It can take longer than just days, most leaks happen for months or more before it builds up enough to get a bunch of citizen complaints and cops go out to investigate. 70% of pipeline leaks are found by cops or civilians, and that is despite most pipelines going through the least dense possible areas without many people around.

That was a runaway train that wound up going 105 kph around a turn rated for 16 kph and derailed on the main street of a town. It wasn't even carrying natural gas, just crude oil. This change to regulations would have no impact on such an event happening again.

If that train had been carrying corn, would the result have been the same amount of damage?

What could have happened on the worst case if the train was carrying LNG?

Natural Gas is lighter than air, not much would have happened.

The LNG would vaporize, rise into the air and there would be a short lived fire.

If you read the damage description it's mostly due to petroleum contamination and fire. None of that would happen with LNG.

The article says that trucks carrying LNG are already allowed in the area, though. Just considering the likelihood of damage to the container, it seems like pipelines > trains > trucks, no?

The problem with pipelines for oil is that they tend to leak in isolated areas, where trains and truck can be maintained at their origin and destination.

It's unlikely that a hundred trucks will all crash at the same time in the same place.

True. The article said that 3 could be transported at once. I don’t know what (if any) limitations there are on the number of trucks carrying LNG in the same area, at once. I’m just thinking that it’s far more likely that a truck would be involved in an accident that involves a fire vs a train.

A large amount of oil comes into New Jersey on a single line near the Hudson river owned by Norfolk Southern. Every single crossing on the line is in a deplorable state of repair where rails are loose enough that they bounce around when cars and trains run over them. A highway grade crossing had collapsed in on itself and they ignored it for a year. They had to be forced kicking and screaming to start fixing them a couple years ago and the work is still ongoing. I wouldn't trust the assholes running these companies or the FRA to maintain safe infrastructure for dangerous cargo. Their current tactic is to punish the towns that complained loudly by ripping up the crossings and then not working on them for a month.

Not saying you are incorrect, but it’s hard to imagine a rail company intentionally leaving a productive line inoperable for a month just to punish a town. They had to have lost a ton of money because of that.

I think the implication of the parent was that the car part was ripped up not the rail part. The line works just fine, just f* the cars that need to cross it.

The rails are still in place with the road blocked.

Then perhaps you should consider the possibility that you're imagining the wrong thing. Greed is indeed a powerful motive, but insufficient as your only roadmap to the world.

What towns has this occurred in?

The ammonia and chlorine tank cars would scare me more. I've seen these running close to residential areas before.

Famous chlorine train incident:

https://en.m.wikipedia.org/wiki/Graniteville_train_crash

Non-mobile link: https://en.wikipedia.org/wiki/Graniteville_train_crash

And nitric and sulphuric acid. And calcium carbide (gives off acetylene if it gets wet). And toxic waste. And literal military bombs.

Warren Buffet likes trains for oil transportation:

https://www.vice.com/en/article/qvamxw/warren-buffett-really...

but a truck or tractor full of LNG can drive directly in front of your house. also some people, _gulp_ actually have a never ending supply piped into their houses directly!

We already see the "Big Rolling Bombs" of crude oil rolling through Hammond, Indiana on their way across the country. I'm very glad I live miles away from those tracks.

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