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whereisthenutella t1_j1961r0 wrote

Reply to comment by GenericUsername2056 in Why do we use phase change refrigerants? by samskiter

Technical nitpicking phase change happens at fixed temperature for a given pressure for pure fluids.

We use mixtures as refrigerant fluids for liquefying natural gas for example although not the only way.

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paulHarkonen t1_j19vkki wrote

I'm curious, what are you using? The only liquefaction plant I've gotten to visit mentioned they were using gas as the working fluid (it was a peak shaving plant) but I have no idea if that's standard or not.

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whereisthenutella t1_j1a6dnr wrote

Regasification I imagine you mean.

Large scale liquefaction will use some kind of proprietary process. The core is a the main cryongenic heat exchanger(s) one or more in series, that is large aluminium multistream exchanger.

The refrigerant is compressed, cooled in the main cryongenic heat exchanger and then expanded and it then becomes the cold stream. The refrigerant is a natural gas mixture adjusted based on the Natural gas composition.

If curious search for LNG MR process, or air products MR process, you are bound to find something.

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paulHarkonen t1_j1a7wpz wrote

No, I meant liquefaction. It's a peak shaving facility so they take from their distribution system, liquify for storage in summer and then re-gasify for injection in winter.

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whereisthenutella t1_j1a8xxy wrote

Ahh okay I haven't encountered cases of that.

At least in Europe there are some underground storage facilities, basically stored in underground caverns (wells) for that very purpose.

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paulHarkonen t1_j1aa45p wrote

They use depleted wells for long term storage of compressed gas but some places also use LNG for on system peak shaving. It sounds from your comment like it's reasonably common to use some processed natural gas (presumably with all the heavies extracted) as the refrigerant feeding the cryogenic heat exchangers.

Thanks.

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