Glycol evaporation

[DemonBrew]

Hi,

I have a glycol chiller which is situated outside.
It feeds 4 x 2bbl fermenters and a 4bbl cold liquor tank.

The glycol storage tank is approx 40 litres.
I have noticed recently an increase in the number of times I have to top up the tank. Becoming to be once a week.

Is this too much? I have checked for leaks and can't see any.

[One2Remeber]

Once a week? I replace the glycol in the chiller every 6 months or so. It feeds 5 5bbl FV. Depends on your size but once a week seems like you have a leak. We had a hole in our long draw chiller the size of a pin and it leaked very slowly over a couple days before we noticed. I would get it checked out.

[jimvgjr]

I agree, this definitely seems like a leak is occurring somewhere in the system. Because of condensation, it can be a challenge to determine the difference between a leak or just sweating pipes.

Some customers have purchased glycol dye to help determine the difference (or used a food coloring), but in small amounts it can be real hard to see the dye. If you notice a spot with consistent leaking or condensation, try to catch in a container- then you can test the sample with refractometer.

Check closely around the pump and tank connections.

Good Luck,

Jim
Pro Chiller Systems

[DemonBrew]

Thanks,

Will check for leaks with food colouring.

I am getting a new supply of Propylene Glycol but it doesn't have any corrosion inhibitors in it.
Is that a concern? The piping to the FV's is copper.

I think the last user of the system was putting in car anti-freeze! Should I try to drain the system completely or will it be ok just to let the level go down and start using the PGlycol?

Finally, the pipes do have a lot of condensation on them.
I take it putting insulation on them should help stop this?

Cheers

[jimvgjr]

Yes, definitely drain the current glycol solution if you suspect it could be an ethylene base (toxic)- even though remote, the risk of this getting into the product is real and not worth taking a chance.

1/2" to 3/4" walled pipe insulation will definitely control and reduce your condensation, as well as reduce heat loss and increase efficiency. Try to seal all joints in the insulation.

You should be fine without a rust inhibitor with copper piping.

Good Luck,

Jim

[DemonBrew]

Thanks guys.

Will check all of the above.

[KWLSD]

If you are able to drain down your chiller of glycol, another way to check for leaks would be to pressurise the empty system with an inert gas (eg. nitrogen).

A slow drop in pressure will indicate leaks and you can also use a proprietary leak detector (or simply a detergent solution) to check around external joints, etc.

It is not uncommon for glycol to leak across the chiller plates due to crevice corrosion in areas of poor flow, so it would be worth stripping the assembly and carefully inspecting, especially under seals, etc.

[DemonBrew]

Have found the leak. It appears that the seal in the pump used to circulate the glycol is leaking.

Will drain the fluid and strip the pump, replacing the seal.
Job done hopefully!

Thanks to all for advice.