Sulphur dioxide

[toprunner]

Hello !

As far as I can see sulphur dioxide (SO2) seems to be a very good refrigerant. It doesnt have the issues regarding high pressure as CO2 (R744) and is not flammable. Anyone have any good information ?? I know it was used in early ages but is not used at all today as far as i can see??

[refteach]

If people think the smell of ammonia is bad, just take a wiff of this bad boy. The refrigerant has that rotten egg smell that you get from sulfur. But if you are sensitive to sulfur (allergies) it can kill you, I am sensitive to sulfur and the moment I can even get a hint of sulfur it starts to get hard to breath, I can't even use a sulfer stick without problems.

An old timer who used to work on Cental refrigeration systems that were popular in apartment buildings, told me a story where there was a leak in a coil in an apartment refrigerator, the Sulfur Dioxide bleached all the veggies and fruit white, preserved them quite well, but took out all the coloring.

[toprunner]

Yes,, i am aware of the smell problem. I had in mind closed refrigeration systems though . The smell can be a benefit since leaks are easy to find. It seems to be easier to use than Ammonia and have pressure range better than R134.. so why not ?? For automobile industry it would be nicer than the CO2 option discussed right now.

[US Iceman]

The only system I remember SO2 being used in were the old General Electric domestic refrigerators called the "Monitor Top", circa 1930 or thereabouts.

It was a good refrigerant, but I seem to remember the system had to be kept extremely dry & leakfree to prevent water getting into the refrigerant though.

I agree it is easy to find the leaks. You sure don't have to look too hard to find them.

Ammonia smells like an air freshener compared to SO2.

[walden]

Don’t you have to use only steel pipe work: because sulphur dioxide will dissolve the copper from pipes and deposit it on the steel compressor pistons so that over time the compressor seizes up? Or am I thinking of some other early refrigerant?

[refteach]

It will make sulfuric acid when exposed to heat, moisture, and air, H2SO4.

[US Iceman]

Hi Walden,

Yes, I think all of the tubing on these units was required to be carbon steel.

On the copper plating issue, I'm not too sure but it does make some sense. If the copper can be dissolved, similar to a acid problem in any other halocarbon system, then the copper could be deposited anywhere in the system.

I have seen some of this on valve plates and oil pumps, but I don't think I have ever seen a compressor seize up. I can't think of a reason why it would not though.

The oil pumps will certainly do this.

[Josip]

Hi,

In CoolPack SO2 is not listed under refrigerants. There must be some reason for that.. beside that evaporating temperature is -10C

http://www.uwm.edu/Dept/EHSRM/CAMPUS/BOL/
http://www.uwm.edu/Dept/EHSRM/HAZCOM...furdioxide.pdf

I will stay with ammonia

Best regards, Josip

[US Iceman]

I think the refrigerant number for SO2 is R-764 if anyone wants to look for properties.

[Paulajayne]

Yes SO2 is R 764

sulfur dioxide, chemical compound, SO2, a colorless gas with a pungent, suffocating odor. It is readily soluble in cold water, sparingly soluble in hot water, and soluble in alcohol, acetic acid, and sulfuric acid. It is corrosive to organic materials and dissolves in water to form sulfurous acid, H2SO3. Sulfur dioxide is used in bleaching and in chemical manufacture and as a refrigerant and a food preservative, e.g., for fumigating fruit. It may be produced by reaction of sulfur with oxygen, e.g., by burning sulfur in air, and it is often produced during the roasting of sulfide ores, e.g., in zinc smelting. Sulfur dioxide is a dangerous air pollutant because of its corrosive properties; it irritates the eyes, nose, and lungs. It is produced by combustion of coal, fuel oil, and gasoline, since these fuels contain sulfur. The sulfur content of a fuel can be reduced by refining, so that less sulfur dioxide is emitted when the fuel is burned.

Paula

[US Iceman]

I also think it reacts with zinc too.

[Paulajayne]

Great site

http://www1.boc.com/uk/sds/all.asp

http://www1.boc.com/uk/sds/special/sulphur_dioxide.pdf

Paula

[Andy P]

Thanks Paula,

That's a really useful link. SO2 had a further advantage in the early days - it acts as lubricant in the compressor and so there was no need for oil in the system. However it is seriously toxic, which was the main reason it fell out of favour in the 1930s when it was replaced by R-12 for small domestic units. Sulphurous acid is almost as nasty as HF (product of combustion of R-134a ) so definitely worth avoiding!

cheers
Andy P

[mickandlee]

Hi
I can remember that about 20 years ago in Central London an ancient thermost capillery was broken releasing the small SO2 charge. This was enough to empty the building and cause the fire and ambulance services attended. - Its that bad.

If I remember it was a good refrigerant, but was only ever used in small open drive compressors and the shaft seals were always a problem. Leaks were always hard to find as you could not get close enough due to the smell.
Some of our mad engineers used a lighted match to find a small leak !!! Same trick was used to discover if a system was charged with R12 or Methyl Chloride. Strangle we never had a major explosion or lost any of these engineers.

Mick

[Andy]

Hi
I can remember that about 20 years ago in Central London an ancient thermost capillery was broken releasing the small SO2 charge. This was enough to empty the building and cause the fire and ambulance services attended. - Its that bad.

Mick

Linde used to use SO2 in their defrost terminatio stats. I remember emptying a supermarket as a apprentice, just had to break the bulb off to prove the stat was still ok to the engineer I was with
He did see the funny side as I got the full brunt of the gas

Kind Regards Andy

[US Iceman]

Here is a link I found to some safety and health effects due to SO2 exposure.

http://www.gasdetection.com/TECH/so2.html

[VS-41]

SO2 will also cause your teeth to fall out if exposed long enough. I knew a man who worked with it back in the 1930s. He said it was used mainley in walk in coolers. He also said it was the best roach killer ever made. one interesing fact, SO2 is a very good lubercant, meaning you do not need any oil in the system.

[monkey spanners]

I think those old teddington QR stats had SO2 in them, Used to take all the duff ones out of dads van for dismantling, used to make you feel like the top of your head was coming off, probhably explains a lot now that i come to think of it!

[US Iceman]

SO2 was used in the first commercially manufactured residential refrigerators. These were made by General Electric and called the "Monitor Top". The reason for the name I suspect is because the refrigeration system sat on top of the refrigerator and looked like the turret on top of the Civil War ironclad called the Monitor.

[NH3LVR]

Many years ago my Dad had a old refrigerator that failed. He went and bought a new one.
Being as the old one was all metal he thought it would make a good smokehouse.
In my ignorance I took and chopped the lines with a axe in order to remove the compressor.
How was I to know that the S02 would kill off the strawberry patch?

[US Iceman]

How was I to know that the S02 would kill off the strawberry patch?

I would be willing to bet, you did not stand around and watch the refrigerant spray from a close location, heh?

I had my first smell of this stuff many years ago at a tender young age and can still remember my grandfather laughing at my reaction to it.