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PROPANE Heat Exchanger + Chiller Recommendations

thcnology

Member

thcnology

Member
Exergy has some baller heat exchangers. Ben at TouchScience sells the best chinese chillers.


I've been looking at Exergy recently as well. BizzyBee is running LN2 thru a "double tube sheet" style HEX. Honestly this may be the only way to get the kinda cooling I need for PROPANE without spending a ridiculous amount on a chiller..still not sure yet.
 

Old Gold

Active member
I've been looking at Exergy recently as well. BizzyBee is running LN2 thru a "double tube sheet" style HEX. Honestly this may be the only way to get the kinda cooling I need for PROPANE without spending a ridiculous amount on a chiller..still not sure yet.

That heat exchanger is around $8000 by the way
 
I'm now looking at using a bunch of peltier elements (TECs) strung together to make a big solid state chiller. 60W units are about $2/ea in bulk so a 6000-12000W system wouldn't be ridiculous, though the other parts of the system like the heatsinks will likely cost much more than the RECs. There are lots of "solid state" lab chillers on the market in the 200-800W range so I think I may just look at how they've done it and go from there. I've also found these beastly 576W finished units with multiple plates already set up with the heatsink/fans for $85 shipped. A string of these could definitely pump some heat...but you still have to get rid of that heat. I'd imagine that I'd have to do some crazy cascading trickery to get anything down to that -40 to -20°C range but, scaling up, it's bound to be cheaper than a pro lab chiller if I build a 10KW+ system.

https://m.ebay.com/itm/12V-567W-8-C...659606&hash=item440bc04634:g:fAoAAOSw8GtZXJpY
 

thcnology

Member
This was taken form another thread...

Using liquid nitrogen or liquid CO2 for cooling

I would like to switch to chillers for all cooling needs (cold traps, gas injection temperature, column jackets, condensing coil/heatexchangers/etc) . However that's a huge cost up front so I will upgrade slowly over time. Until then I want to get away from dry ice/alcohol mixtures, as that gets expensive over time. It seems to me that using liquid nitrogen or liquid CO2 would be the most cost effective method of cooling at this point.

Before I pick some up though I have a few questions:

Is the use of either of these liquids both effective and efficient for all cooling needs? Which do they work for and which do they not?

How can the temperature of the liquids be controlled? Liquid nitrogen boils at -321F. How would I use it to get my gas to around -30F?

While liquid nitrogen boils at -321*F, you aren't actually going to get anywhere close to that right away because of the thermal mass at a way higher temp that is already present in the system (thermal enthalpy)

As for your second question, I think the DIY way to do it would be a temperature probe set up with a PID controller and a solenoid hooked to your LN2/CO2 tank. May also require some sort of needle valve to throttle the amount that comes out at once.

LN2 works well for subzeroing LPG prior to injection, but wouldn't be the best choice for cooling pump discharge.

We used a counterflow exchanger and injected liquid N2 in one end of the jacket and discharged N2 vapor out the other.

We control the temperature with an orifice on the discharge end of the jacket, and by the rate of flow of the LPG passing through the center heat exchanger tube.

Again this thread is about PROPANE not BUTANE..and seriously I'm not looking to jerry rig a bunch of Chinese junk together..I need a simple efficient time tested based on science plug and play design combination that actually works and doesn't cost 50K.

Sooo...I like this LN2 idea more and more for CHILLING and condensing my PROPANE pump discharge...and as opposed to the counterflow HEX design using a double tubesheet HEX design. I may even be able to have this HEX fabricated for about half than an Exergy but I am having a lil trouble finding a decent diagram of one for my guys or coming up with the appropriate dimensions. I really like this idea above for a basic DIY setup with a thermoprobe PID and solenoid hooked to LN2 tank for some automation.
 
Originally Posted by Gray Wolf...

GW I stole this from another post of yours..I think my math is right?? and lets assume exhausts at 120F...

The latent heat of vaporization for n-Butane is 165.6 btu/lb, so that converts to about 48.5 Watts per pound.

The latent heat of vaporization for PROPANE is 184 btu/lb, so that converts to about 53.9 Watts per pound.

https://www.engineeringtoolbox.com/butane-d_1415.html
https://www.engineeringtoolbox.com/propane-d_1423.html
https://www.rapidtables.com/convert/p...TU_to_Watt.htm

You have to remove both any heat added by the pump, as well as the heat of vaporization to return it to liquid state at about (31.2F for BUTANE)...((-44F) for PROPANE)

You can measure the temperature of the gas exiting your pump closely enough for our purposes, measuring the plumbing fitting at the pump discharge with a hand held infrared thermometer.

If you subtract (31.2F for BUTANE)...((-44F) for PROPANE) from that reading, you will have your delta T for your calculations.

The specific heat of both BUTANE and PROPANE is 0.39 btu/lb/F, and can be found in the engineering toolbox links above.

It says that it takes 0.39 btu’s per pound for both BUTANE and PROPANE, to raise its temperature 1 degree F.

So if you pump exhaust is 120F, your delta T is 120F – 31.2F= 88 degrees delta T for BUTANE.
So if you pump exhaust is 120F, your delta T is 120F – (-44)F= 164 degrees delta T for PROPANE.

Soooo, 1 lb of n-butane at 88 degrees delta T, requires 88/0.39=225.6 btu to return it to 31.2F.
Soooo, 1 lb of PROPANE at 88 degrees delta T, requires 164/0.39=420.5 btu to return it to -44F.

BUTANE 225.6 btu + 165.6 btu heat of Vaporization = 279.8 btu/lb to remove to return it to liquid state.
PROPANE 420.5 btu + 184 btu heat of Vaporization = 604.5 btu/lb to remove to return it to liquid state.

Using the converter above, that is about 82W per pound for BUTANE.
Using the converter above, that is about 177W per pound for PROPANE.

So ~50lb*82W=4,100 Watts for BUTANE??
So ~50lb*177W= 8,850 Watts for PROPANE??

I think this is right GW slap me if I’m wrong…SMH..I deduce from all this that chilling PROPANE is TWICE as Hard and TWICE as Expensive but I sorta already knew that:tiphat:

So from looking at this these formulas how would I use these equations to calculate the BTU or watts required in order to turn the liquid into a gas constantly
 

Gray Wolf

A Posse ad Esse. From Possibility to realization.
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Veteran
So from looking at this these formulas how would I use these equations to calculate the BTU or watts required in order to turn the liquid into a gas constantly

Are you asking about turning liquid N2 into a gas?

N2 has a specific heat of about .25 btu/lb/F and a boiling point of -320F, so typically at around -321F in Dewar.

Heat of vaporization is 1.200688 btu/lb.

Sooo, it will take about 1.45 btu/lb to turn it from a liquid to a gas, but cooling continues as a gas, as the gas is still cryogenic.

Stainless steel has an R Value of about 1.4 btu/ft2/F/hr, which at 1/1.4 would give a K Value of about .714 btu/hr/F/ft.

With a boiling point of -43.6F, and N2 at -320F, the delta temperature is about 276 degrees F.

That brings us to residence time, which is how long the propane and N2 share the same heat exchanger, which is a function of size of the HEX and propane flow rate.

What exchanger, and what rate are you planning?
 
Are you asking about turning liquid N2 into a gas?

N2 has a specific heat of about .25 btu/lb/F and a boiling point of -320F, so typically at around -321F in Dewar.

Heat of vaporization is 1.200688 btu/lb.

Sooo, it will take about 1.45 btu/lb to turn it from a liquid to a gas, but cooling continues as a gas, as the gas is still cryogenic.

Stainless steel has an R Value of about 1.4 btu/ft2/F/hr, which at 1/1.4 would give a K Value of about .714 btu/hr/F/ft.

With a boiling point of -43.6F, and N2 at -320F, the delta temperature is about 276 degrees F.

That brings us to residence time, which is how long the propane and N2 share the same heat exchanger, which is a function of size of the HEX and propane flow rate.

What exchanger, and what rate are you planning?
I'm trying to heat water in the jackets below my honey pots in order to gas off 70/30 pro butane mix, I wanna keep the water at 105 F so I can gas off fast enough for my recovery pumps to be supplied constant amount of gas
 

Zipsort

Member
i use the the #20bhogart for injection the #100 is covered in ice next to it. i use Dynalene HC-50 and a 80/20 butane/propane.

Wow, you got a ballin setup. I have just the #20 mounted on my solvent tank for recovery.. Is there a chiller you think that would keep up with just the small one? Preferably without adding any ice.
 

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