SO2 filter

I had two different people who are, or where chemists tell me they saw absolutely on reason a drier wouldn't work with methyl formate. I assume the same is true for SO2.

They told me to stay away from pellet types and to go for the solid core ones. They also said no company would put their neck on the line for something they had not tested, however the worst that could happen is the drier would absorb the refrigerant and then be useless, but no harm would come of it.

I did not plan for it, at least not yet but I am tempted in the future.

This is the actual response from one of the guys I had asked.

"Chris,

Although no one is willing to go "out on a limb" to guarantee refrigerant compatibility, refrigerant desiccants generally fall into two categories- activated alumina and molecular sieve materials that generally looks like this: Ca4,5 [(Al02)12(SiO2)12] · nH2O. There are variants to the m-sieve, changing the cation varies the pore size. Not really an issue for you.

Most good line driers are a mix of pellets of alumina and m-sieve pellets. There is some compatibility issue with m-sieve using certain 500 class HCFC's, but no reported issues with straight HC refrigerants. The 'issue' is not severe, it is simply binding of the refrigerant to the substrate, reducing the active refrigerant level in a system. There is no chemical breakdown of either that I can see that would produce acids or contaminant release.

One issue I did (I think?) mention earlier was abrasive fines in the system, and unfortunately all pellet filled driers produce them as they age. For this reason I would use a solid-core rather than pellet drier if possible.

I have a .pdf from Parker Hannifin explaining their solid-core line (Spoorlan Catch-all) and showing the internals of both pellet and solid core driers. I cannot attach it here to a PM so I will email it if you provide an email address."