propane bottles freezing

[WantedWolf]

Were having problems keeping our 100lb bottles of propane in liquid form. Has anyone tried the heating units used in water bed bladers to wrap the bottles? they are thermostatically controlled so it should be safe and waterproof although not grounded.

 

[CCWKen]

Are you talking about the valve or regulator? Propane freezes at -310F. I don't think it gets that cold even in Alberta. Propane remains liquid to -44F (boiling point). For a tank to expell vapor, the liquid must be maintained above -44F. It's self cooling so as it boils, it cools the remainder of the liquid.

If you do want liquid out of the tank, it must be valve down (or a special tank) and be kept at about 60F to maintain vapor pressure in the tank. It's common to use a heat wrap in cold temperatures for automotive air conditioning refrigerants. The same problem occurs when trying to charge an A/C system in cooler temperatures. You can't get gas or liquid out of the tank. Use a heat wrap designed for propane. DO NOT use a heating blanket or pad.

 

[CurlyDave]

I think it would be a lot safer to just put a fan blowing air over the bottles.

As propane evaporates from the liquid in the bottle the latent heat of vaporization must be replaced. In ordinary conditions, enough heat will transfer into the tank to make up this latent heat and even though the bottle will drop in temperature, gas will still come out. In very cold conditions, you will not get enough heat transfer.

While a heater of some sort will work, the real problem is finding one rated for this service. While there are a lot of heaters which are probably safe for this application, getting one the manufacturer is willing to recommend and test for this is going to be difficult. The market is small, but the liability is large.

A fan will increase the heat transfer rate from the ambient air to the propane bottle without ever contacting the bottle. It is an inexpensive way to do a lot of good.

 

[mbohuntr]

Thank-you... I just learned a lot!

 

[Egon]

WantedWolf, Check your regulator size against the flow demand you have. It may be possible a larger regulator would alleviate your problem by reducing the differential pressure across the regulator. You can get quite a bit of cooling across the regulator when the differential pressure is high.

Another thing to consider may be several regulators to help reduce the differential cooling and pressure.

You may also consider covering the top of the bottle and placing a light bulb under it. This has worked for some people but I am not sure of the safety factor?

Others have built fires under their tanks but those were usually on 500 gal plus tanks!

If it is an uncommon thing placing cloths around the regulator and pouring hot water over them may thaw a frozen regulator.

Main thing is to keep safety factors in mind.

Lovely weather you are having out West right Now! I can remember a few time just like it when I lived in Alberta.

 

[tommu56]

I think it would be a lot safer to just put a fan blowing air over the bottles.

As propane evaporates from the liquid in the bottle the latent heat of vaporization must be replaced. In ordinary conditions, enough heat will transfer into the tank to make up this latent heat and even though the bottle will drop in temperature, gas will still come out. In very cold conditions, you will not get enough heat transfer.

While a heater of some sort will work, the real problem is finding one rated for this service. While there are a lot of heaters which are probably safe for this application, getting one the manufacturer is willing to recommend and test for this is going to be difficult. The market is small, but the liability is large.

A fan will increase the heat transfer rate from the ambient air to the propane bottle without ever contacting the bottle. It is an inexpensive way to do a lot of good.

Dave got it I had the problem at my cabin and the propane guy said it was not enough surface area of propane and of the tank above the liquid line so he said i would need a horozonal tank = more surface area but they dont deliver to were I am ar so I ended up putting 6 100lb tanks all on line in the winter to give me the area required and cart them back to him when they need filling in the summer.

tom

 

[ragkar]

What is the size of your 100lb tanks? I had a delivery guy tell me that I have a 100lb tank but I don't believe him because it's 48inch high by 30inch diameter and that calculates to 150 gallons. Allowing for partial filling, I think that I might have 100 gallon tanks but I'm not sure.

 

[Egon]

In here you will find a 100 pound C3 bottle.

Propane Cylinder and LPG Bottle Information

 

[WantedWolf]

Yeah im sorry about the wording I suppose I dont really want the propane in liquid form but not gel either. Weve been sitting here at about -30 for over a week. My friend in the valley is trying to survive the winter in a 96 bounder bus with no shelter around it we have hay bales around the whole thing past the skirt. the water keeps freezing in the distribution line only propane vents lead to the water bay and he's pluged into 120v but maxing out his supply with electric heaters and drilled quite a few vents himself.

when he asked me to look out for a water bed heater I thought it was a good idea.there is no inside to store the tank but we have it surrounded by hay aswell. he thinks hes not getting enough propane to run the heaters at an effective level. Ill talk to him about multiple regulaters but Im not sure I understand how that would help? he told me last night hes thinking of warming them with the tiger torch

Im not complaining about the cold lets keep it coming and wipe out the pine beetles.

 

[ragkar]

Egon, thanks for the info.