A safe propane storage?

[John Cuthber]

The freezing point of butane is -140C. That's 40 degrees colder than the worst bits of the antarctic. Butane didn't freeze in the pipes.

The difference in boiling points is significant.

[tinkerer]

On 12/19/2018 at 3:26 AM, John Cuthber said:

The freezing point of butane is -140C. That's 40 degrees colder than the worst bits of the antarctic. Butane didn't freeze in the pipes.

The difference in boiling points is significant.

Correct. However, the concern is that if the liquid will not BOIL, no pressure to deliver it is readily available. IOW,

"Butane boils at -0.5°C so when the ambient temperature falls to around freezing no gas is produced and even at around +4°C the pressure is too low to be useful.
Propane boils at -42°C so can be used in arctic conditions.

[Moreno]

On ‎12‎/‎22‎/‎2018 at 11:08 PM, tinkerer said:

Correct. However, the concern is that if the liquid will not BOIL, no pressure to deliver it is readily available. IOW,

"Butane boils at -0.5°C so when the ambient temperature falls to around freezing no gas is produced and even at around +4°C the pressure is too low to be useful.
Propane boils at -42°C so can be used in arctic conditions.

A sorbent could reduce propane tank weight a lot and allow to make it of more conventional and cheaper squarish shapes. Commonly propane liquifies at 12-15 bars and require heavy tank. In a sorbent it can be stored at 1 bar pressure or even lower what still may provide sufficient supply to the engine. 

[Moontanman]

It's my understanding that during or just after the gasoline crisis of the late 70s propane and natural gas was proposed as a replacement for gasoline powered vehicles. Propane is quite popular in some places even today. Construction sites and other businesses use propane powered vehicles as do some fleet trucks. Propane is said to contribute to long engine life and it burns somewhat cleaner. 

Natural gas was also touted as a replacement for gasoline and quite a few vehicles were produced. Most filled up at home from natural gas lines with a small compressor. Neither gained widespread popularity probably due to limited places to fill up and the cost of conversion. 

Many car companies still offer conversions for their light trucks to allow them to use propane and natural gas..  

[Moreno]

2 hours ago, Moontanman said:

It's my understanding that during or just after the gasoline crisis of the late 70s propane and natural gas was proposed as a replacement for gasoline powered vehicles. 

What do you think could become the most common type of a motor fuel, if plug-in hybrid will become the most common type of vehicle and cars will use only 10% of fuel they use today? I think for now there may be insufficient supply of propane or ethanol to replace all the gasoline and diesel, but what if cars will use many times less fuel than now? Will global transition from gasoline and diesel to cleaner fuels make sense?

[John Cuthber]

On 01/01/2019 at 12:48 AM, Moreno said:

A sorbent could reduce propane tank weight a lot

How?

[Moreno]

5 hours ago, John Cuthber said:

How?

I've already explained this. By reducing pressure on tank walls many times.

[tinkerer]

On 12/31/2018 at 5:48 PM, Moreno said:

A sorbent could reduce propane tank weight a lot and allow to make it of more conventional and cheaper squarish shapes. Commonly propane liquifies at 12-15 bars and require heavy tank. In a sorbent it can be stored at 1 bar pressure or even lower what still may provide sufficient supply to the engine. 

Acetylene gas is stored in steel tanks in fashion similar to your description. It is absorbed by an inner material, carbon, I believe, possibly saturated with acetone, but I forget where I heard that. Typical pressure encountered with usual surrounding temperatures is several hundred pounds per square inch. I have always heard it is stored thusly for purposes of safety, but never understood the issue. 

I expect @John Cuthber has greater knowledge of this than I, and perhaps he will share.

On 12/31/2018 at 5:48 PM, Moreno said:

A sorbent could reduce propane tank weight a lot and allow to make it of more conventional and cheaper squarish shapes. Commonly propane liquifies at 12-15 bars and require heavy tank. In a sorbent it can be stored at 1 bar pressure or even lower what still may provide sufficient supply to the engine. 

Interesting to note here that it is common practice in industry (at least here in the States) to use liquid propane fed directly in that form to the engines of fork-lift trucks. Perhaps delivery volume is inadequate in gas form, made even worse by the cooling effect on the tank of gas leaving it, which lowers the pressure. Such operation would likely be unstable. Delivering liquid ensures fairly constant pressure, so long as surrounding temperature remains relatively constant.

On 1/1/2019 at 1:24 PM, Moreno said:

What do you think could become the most common type of a motor fuel, if plug-in hybrid will become the most common type of vehicle and cars will use only 10% of fuel they use today? I think for now there may be insufficient supply of propane or ethanol to replace all the gasoline and diesel, but what if cars will use many times less fuel than now? Will global transition from gasoline and diesel to cleaner fuels make sense?

IMHO, a glut of gasoline will present itself should a fairly rapid transition, say, changeover for a following model-year occurs, making it the predominating fuel. However, gasoline prices are highly variable, and quite manipulable. I should think if considerable differences exist regarding exhaust emissions between liquid fuel and gaseous, that will affect the result. Hydrogen usage, of course, is most preferable in that respect. Personally, I've witnessed too many hydrogen explosions to yet become comfortable with it's general use. Ask the Germans!

Edited January 7, 2019 by tinkerer
better wording