Without thinking too much on it I believe they should be close to equal but the cold side may be slightly smaller due to heat and pressure losses in plumbing between the two sides. You need to know not just how many units of power are “created” in your Heater and chiller but how many are actually transferred in your cold and hot heat exchangers. this can be done by evaluating the inlet and outlet conditions of one or both streams in your HEXs to calculate the energy gain or loss of that stream.
Ex:
Looking at the glycol stream of cold side HEX and measure inlet and outlet temps and the flow rates of glycol. Then;
Power (kW) transfered to hydrocarbon from glycol in Condenser HEX= mass flow rate glycol (kg/s) x specific heat of glycol(Cp = kJ/(kg x C or K) × inlet temp vs outlet temp of glycol (C or K) units work out to kJ/s or kW.
Assuming no loss of energy to surroundings (good approximation if HEX is insulated) then energy gained in glycol heating has been energy lost in butane cooling.
I didn’t know what to search for my friend, this is why I asked specifically “how do we reference the math” and not “what is the math”. Thank you very much for that thread. I also assume - and this assumption could be off base - that the requirements and balance for a traditional jacket - tank or jacket - coil - tank system would be different from one where you’re attempting to continuously evaporate and recondense your solvent on the fly.
Is there a difference in evap calcs between a tube in shell and a tube in tube?
The surface/transfer area of a 6" or 8" x 36" spool(w/ heated jacket) is greater than the op’s bvv 19-3/8" tube’n shell, so the transfer rate should also be greater? If using a 180° hollow cone nozzle to evenly coat the sidewalls thats seems potentially better than trying to evenly fill a tube sheet on a shotgun style.
Also a plate exchanger could be interesting and provide a bit more surface area than both tube n shell or tube n tube. There’s some other cool ideas that I think could work paired with a possible cross flow heater similar to what boomtown was doing.
yeah i was curious about pre chilling as well. but one concern i have with pre chilling for injection is that it may clog up due to moisture if there is any present… or even clogs condensing on the recovery side…
ive heard some people have troubles boiling with hydrocarbons on tube n shell… cant imagine what kind of nightmare that would be in a plate exchanger.
Anyone have any experience with it? Doesn’t seem to be for sale anymore or atm.
Kinda dont like the recovery through the same lid idea, but it seems designed as a non shell and tube falling film, kinda conversion kit thing, which is a method im still contemplating and cost comparing.
I think Im going to use a full “surge tank” to collect before evaporation so as to get the solvent off the material and will use it to preheat before “injection”. Might split my days work into two parts 1.blasting tubes into surge tanks, then 2. running them through the evaporator.
Been eyeing up the BETE CW series nozzle, Im shooting for 1 to 2 Lbs / min type speeds so kinda have to decide between the CW25 or the CW50. They are $100usd from my local supplier, but with a 6week lead time.
Question about common setups, using the ETS falling film unit as the example. Is the tube above and attached to collection pot/chamber also a shell and tube and is it used heated to evaporate and catch any remaining entrainment?
Ill be using dry ice to condense, so was thinking about the shotgun style condenser, have only seen them available or in stock at BVV.
Ive seen some of the kerfuffle about the design, @FicklePickle where do you recommend one to procure such a designed unit? Do you care or am I copy and pasting some designs to china fabs?
Who’s running smaller units, 3-5lb material, 20 - 30lb solvent, with falling film methods!? Share some thoughts please!
You’re going to hate how much dry ice you eat up. If you’re going to use dry ice at all I’d recommend using multiple stage cooling via multiple tube and shell condensers in sequence and having one tube and shell hooked up to something to bring temp down to around 0c and then the dry ice essentially cools the rest of the way down to below 0 temps. You gotta remember, a lot of energy is used just for the phase change (turning from gas to liquid) so expecting your dry ice to do a phase change and also cool it down significantly is going to be a burden on your dry ice budget. Ultimately I think tube and shells are better off paired with badass chillers.
That being said, this process is extremely dangerous and without knowing how to calculate kw of heating vs cooling needed, surface area efficiencies in your heat exchangers, you’re going to be risking a very dangerous situation creating that much vapor.
There is a BFFE on the Bzb Beest, its 48inches tube in shell, with the chiller at -30 it recovers 20lbs in 9 minutes @ a 33c boil passively with no nozzle
I honestly don’t know why you would want to evaporate and condense butane any faster than that, we have trouble keeping up as by the time you clear a shot and reload the collection is syrup
Definitely going to have some water chilling before the dry ice, Its cold here so I try to utilize the free cooling as much as possible.
Ive been using GrayWolf’s Lair thermodynamic resources and examples to help my size figuring. 7.5sqft’ish surface area to condense 1lb/m with dry ice, or 71.5’ of 1/2" coil.
Good call with the chiller, I will eventually switch to one, but its not in my cards for this season.
@Myrrdin
Is that a 6" diameter shell on you condenser? Any idea of the surface area or number and size of tubes?
I aint looking to go over 2lb/min, Id be okay with 1 but am looking for a bit more.
You do have me wondering about the falling film though, perhaps it isnt necessary.
I dented my 12x12 collections last year so need a new solution, main priority is to not use any large clamps.
@FicklePickle
Cool, not sure Im going to go that route, gotta budget it. I was looking at your drawings in the prior art dump thread.
please.