Methane storage

[Moreno]

What could be done in order to store liquid methane at room temperature? Possibly some "super-additives" which are capable increase boiling point dramatically?

[Robittybob1]

Not much below room temp as methane hydrates.

[Moreno]

What do you think about this "patent"? They claim 67% of gasoline energy density. And propose to store methane in light hydrocarbons.

http://www.google.ca/patents/US5900515

Edited March 18, 2016 by Moreno

[Robittybob1]

What do you think about this "patent"? They claim 67% of gasoline energy density. And propose to store methane in light hydrocarbons.

http://www.google.ca/patents/US5900515

If it requires active cooling between those temperatures it sounds like a problem for the cooling apparatus may breakdown. What sort of danger would the operators be in if the cooling mechanism failed?

Where is equation 2?

 

The amount of heat transferred to the fuel 30 from its surroundings may be calculated according to the following equation: ##EQU2## where q is the amount of heat transferred

Edited March 18, 2016 by Robittybob1

[Enthalpy]

The industrial way is to liquefy, store and transport methane under cold. As is, it doesn't exist liquid at room temperature, whatever the pressure. I suspect many people searched for an alternative but the most convenient way is cold - not a big problem.

 

Dissolve under pressure in a heavier alkane... Then you have to store and transport the alkane, which expectedly is heavier than the dissolved methane, and this needs still a vessel which may be less convenient than a vessel for cold.

 

If you want methane as a fuel whatever its form, you could convert it to something else, like methanol (poison) or heavier compounds easy to use.

 

It's all a question of "what effort" compared with "what benefit".

[Moreno]

Experimental results for methane adsorption on two high-surface area carbons (TE7-20 and AX-21) and one metal-organic framework (MIL-101(Cr)) are presented, with isotherms obtained at temperatures ranging from 250 to 350 K and at pressures up to 15 MPa. The isotherms were analysed to determine if these materials could be viable alternatives for on-board solid-state storage of methane. The results show a very high adsorbate density in the pores of all materials, which for some can even exceed liquid methane density.

http://opus.bath.ac.uk/43715/

These claims sound a bit unbelievable. Energy density of liquid methane comprises 2/3 from energy density of gasoline and if some materials allow the same or even higher density for adsorbed methane, why there is still no global efforts to replace all the gasoline and diesel with methane?

 

This one article mentions 500 v/v methane uptake at 400 bars, compared to 600 v/v of liquid methane.

http://onlinelibrary.wiley.com/doi/10.1002/ente.201600172/abstract

Edited April 27, 2017 by Moreno

[jessehk]

Maybe pressurize it in a container rated for pressure. (Or just put it in and let it pressurize itself). Not sure though.

[Moreno]

Maybe pressurize it in a container rated for pressure. (Or just put it in and let it pressurize itself). Not sure though.

 

At the moment I'm a theoretician.

[Moreno]

Does it make any sense to use cylinders which are capable to withstand extremally high pressure (around 600 bars) and which could be filled with liquified methane (LNG)? They could be used instead of thermally insulated tanks in which LNG can be stored just a few days without significant losses. What pressure will they need to hold when LNG will get ambient temperature? Will it require some supermaterials?

[mistermack]

They are shipping the stuff in some pretty big tankers. I believe they are cooled. Obviously they reckon they can manage the risk :

http://www.nbcnews.com/id/4276348/ns/us_news-security/t/are-natural-gas-ships-boat-bombs-terror/#.XeGOjJP7Sos  

[Moreno]

34 minutes ago, mistermack said:

They are shipping the stuff in some pretty big tankers. I believe they are cooled. Obviously they reckon they can manage the risk :

http://www.nbcnews.com/id/4276348/ns/us_news-security/t/are-natural-gas-ships-boat-bombs-terror/#.XeGOjJP7Sos  

I meant to use LNG in vehicles as a motor fuel. Obviously constant refrigeration isn't attractive option and it does suppose to be stored for indefinite period of time. Therefore some very high pressure cylinders are needed.

[mistermack]

3 minutes ago, Moreno said:

I meant to use LNG in vehicles as a motor fuel. Obviously constant refrigeration isn't attractive option and it does suppose to be stored for indefinite period of time. Therefore some very high pressure cylinders are needed.

I used to have a van that ran on dual fuel, LPG and Petrol, switchable between the two. The cylinders were very heavy, but not too bad for a van. But in a car, the weight and space is a liability. I believe that LNG cylinders would have to be much thicker and heavier still than LPG. 

Then they might be more explosive in a fire as well. I think it's probably a non-starter for cars. Don't know how it compares to hydrogen though. That might give a clue as to what it would be like.

[Moreno]

12 hours ago, mistermack said:

I believe that LNG cylinders would have to be much thicker and heavier still than LPG.

Then they might be more explosive in a fire as well. 

Isn't something like Kevlar laminated Titanium going to work and be light and cheap enough?

Commonly it is claimed that it is a methane fumes which are explosive. (But the same is true about gasoline fumes.) Not LNG by itself. There is a trick when a burning match is extinguished by putting it in LNG. 

Edited November 30, 2019 by Moreno

[mistermack]

That actually sounds expensive, not cheap. Not that I know much about manufacturing costs. But also, it doesn't sound like it would be safe in a fire, which is important for use in vehicles. 

[Moreno]

6 hours ago, mistermack said:

But also, it doesn't sound like it would be safe in a fire, which is important for use in vehicles. 

Why should it be more dangerous than gasoline?

[John Cuthber]

On 4/4/2016 at 5:53 PM, Enthalpy said:

As is, it doesn't exist liquid at room temperature, whatever the pressure.

A few years ago, Enthalpy made that simple, easy to understand observation.
And yet we still have people asking things like this.

22 hours ago, Moreno said:

 What pressure will they need to hold when LNG will get ambient temperature?

 

[mistermack]

2 hours ago, Moreno said:

Why should it be more dangerous than gasoline?

I meant the Kevlar, not the natural gas. I'm guessing that it wouldn't survive well in a fire. 

[Moreno]

8 hours ago, mistermack said:

I meant the Kevlar, not the natural gas. I'm guessing that it wouldn't survive well in a fire. 

What about gasoline plastic tanks? And there are plenty of strong materials that do not burn. 

On 11/29/2019 at 5:24 PM, mistermack said:

Don't know how it compares to hydrogen though.

Toyota Mirai suppose to store hydrogen at 700 bars. These cylinders do not look extremely thick. Methane at that pressure would probably have 2/3 volumetric density of gasoline.

https://en.wikipedia.org/wiki/Toyota_Mirai#High-pressure_hydrogen_tanks

[mistermack]

There is some tried and trusted technology available : 

[dimreepr]

1 hour ago, mistermack said:

There is some tried and trusted technology available : 

like this?

[Moreno]

Please, correct me if I'm wrong, but it looks like Toyota Mirai hydrogen cylinders are just about 2 times thicker than regular hydrogen tanks. And there seem to be no metal. What a miraculous material is it? What will happen in a case of a car crash? Will it explode?

[Enthalpy]

As far as I know, all manufacturers of hydrogen cars store hydrogen under pressure at room temperature.

Much research proposes to adsorb the hydrogen, make hydrides, compounds hydrogenated at will (cyclohexadiene <-> benzene), cool the hydrogen without liquefying it, and so on. I suggested to use abnormally light alloys and in magnetostrictive and shape-memory alloys
https://www.scienceforums.net/topic/79128-alloys-to-store-hydrogen/I do believe storing the hydrogen as a liquid is excellent for the mass and the evaporation rate is quite acceptable for a vehicle serving regularly
https://www.scienceforums.net/topic/73798-quick-electric-machines/?tab=comments#comment-738806
that would be perfect for helicopters and quadcopters, excellent for airliners. Less good for a car that may be immobile for months, but then a fuel cell can consume the boiled hydrogen to cool the remaining liquid. It was a project at Nasa for space probes, by the way.

What happens to a hydrogen tank in a crash? Much the same as to a gasoline tank. In a small crash, nothing. In a big crash, leak. Difficult vehicle design saves the passengers up to 70km/h crash in good circumstances. What happens to the tank at 100km/h is less important if the passengers are dead anyway.

A tank that resists 70km/h within a deformable car doesn't seem very difficult to me. For crash-tests, I build hardware, indefinitely reusable, that decelerated from 120km/h within 0.15m, that's worse than a crash. Both metal and fibre tanks are conceivable.

Storing methane is much like hydrogen, only easier, both as a gas and a liquid. Denser, less cold, leaks less, more heat capacity.

With battery cars being simpler, easier to fill, and available, I fear the attempts with hydrogen cars are over. But for helicopters and airliners, batteries are far from satisfying presently, while hydrogen looks perfect.

 

[Moreno]

How much LNG pressure suppose to increase when it will reach room temperature?

Edited December 6, 2019 by Moreno

[swansont]

37 minutes ago, Moreno said:

How much LNG pressure suppose to increase when it will reach room temperature?

At STP, an ideal gas occupies 22.4 liters per mole. If we start with a volume of 0.224 liters (you'd need to do the calculation to get the exact number), you could apply PV= nRT. At room temperature, the gas will exert 100 atmospheres in that volume. That should approximate what would happen for a non-ideal gas.

[Moreno]

3 hours ago, swansont said:

At STP, an ideal gas occupies 22.4 liters per mole. If we start with a volume of 0.224 liters (you'd need to do the calculation to get the exact number), you could apply PV= nRT. At room temperature, the gas will exert 100 atmospheres in that volume. That should approximate what would happen for a non-ideal gas.

Maybe you may make calculation for methane in particular? For example, if we fill some cylinder with LNG and will wait when temperature of LNG will become equal to room temperature. How much pressure on cylinder walls it will exert now?