Im building a large SS crystallization reactor, i need some recommendations for pumps rated for pentane, anyone have any ideas?
would something like this work; https://westechequipment.com/product/110700-04-12-gpm-methanol-pump-1-in-inlet-3-4-in-outlet-115v-ac-pump-only?gclid=EAIaIQobChMIqJHomPT_4AIV0Rx9Ch0L4g0qEAYYASABEgLdq_D_BwE
is filling with vacuum my best bet???
flow rates are arbitrary, the vessel in question is 33 gallons, it doesnt matter to me how long it takes to fill, just as long as its filled safely and somewhat autonomously.
thanks,
RS
1 Like
I’d go with vacuum. Treat pentane more like butane than ethanol even though its liquid at room temp it’s pretty volatile. That being said you could get a diaphragm pump like the MVP Liquid pump.
https://bhogart.com/master-vapor-pumps/
4 Likes
I kinda figured vacuum would be the best route! thanks for the link ill check them out!! 
A sand piper diaphragm pump would be much cheaper and could still handle the flammable vapor without ignition.
The problem with one of those sand pipers would be metering the amount of liquid your pumping out tho.
Edit: honestly that methanol pump you posted seems like a better option than a sandpiper, are the internals of that methanol pump food grade?
3 Likes
Ive looked at the sandpipers before, they are pretty nice looking, also air powered which is always a plus.
metering is going to be tricky no matter what, ive been considering a peristaltic, it would be slow, and filling would take forever, but i could accurately get the ratio i need with such a pump.
Im going to use the totalizer function of this flow sensor to determine the incoming volume, they are pretty awesome units, ive worked with them before. GPI G2S Series 1 in. Stainless Steel Tri-Clover Meter w/ 1 1/2 in. Clamp Ends - Gallons - John M. Ellsworth Co. Inc.
ive even been thinking about a tandem system with a mass volume pump to get it mostly full, then switching to a dosing pump to get it to the perfect ratio. this is added complexity and cost, but it would be sweet, but im trying to keep this system as KISS as possible, filling the unit with pentane quickly isnt necessarily a problem.
good point about the food grade, im unaware, it doesnt say it is so im going to guess no, ill have to find something food grade, i may have to look a little harder for one. may be one of those things you have to special order from a pump supplier.
2 Likes
A tandem system came to my mind as well, but that would be breaking your KISS rule 
Have you taken a look at Micropump’s mag drive gear pumps?
They offer models with stainless steel and teflon encapsulated magnetic drives, I doubt the motor will be explosion proof unless specified though. Shouldn’t really be a problem if you can adequately isolate the unit from any vapor.
http://www.micropump.com/technology_drives_technology.aspx
1 Like
good recommendation, ill check them out!
vapors are a big concern, im hoping to condense majority of them in a cold trap, mainly during the heat ramp to get everything in solution.
1 Like
That triclamp meter you posted was pretty snazzy, I didnt even know something like that existed.
Theres not much info in the description, do you know if it is compatible with hydrocarbons?
1 Like
yeah all the wetted parts have good resistance.
im also considering an inductive flow meter instead of a impeller meter, they have no moving parts at all! they even have some that are non invasive, you just clamp them on to a triclamp and they sense through it.
https://www.automationdirect.com/adc/overview/catalog/process_control_-a-_measurement/flow_sensors/magnetic-inductive_flow_meters are freaking dope, just unsure of how effective it would be for pentane, i need to call them up and ask them
the clamp on ones are like; Clamp-On Transit Time Ultrasonic Flow Meter
only problem with the non invasive ones is they sense best if there are particles in the solution to reflect the waves.
oh for anyone reading this and considering a meter. GROUND IT.
4 Likes
no electronics is safest! i like it, ill check those guys out.
good recommendation!
We can get some pretty rugged diaphragm pumps, and containment duty pumps from sandpiper,
the supply house is a stones throw from our machine shop. ideally you want a diaphragm pump with a ptfe diaphragm, and flap valves for low pumping speed. Preferably you’d get the pump in a all stainless configuration. Sandpiper to my knowledge is the only company that does the ptfe diaphragm, they call it the Synthesis diaphragm.
4 Likes
with a diaphragm pump do you recommend using a pulsation dampener?
Consider that boiling point is dependent on pressure and pumps (and vacuums haha) reduce pressure, on a warm day a pump or vacuum could well put pentane past boiling point, then your pump will be pulling pentane gas which is more like butane than liquid pentane. This stuff obviously can drop back to liquid state pretty easily
3 Likes
thats an excellent point, thanks for your input. I wonder if prechilling the pentane before pumping would help keep most of it in the liquid state.
One would assume though that his solvent tank has a dip tube that extends the the bottom of the tank.
Same as we use butane, pulling solvent from the bottom of the tank so even under pressure you are always pumping liquid.
1 Like
yeah ill be pulling through a dip tube, the ultimate goal is to just pull directly from a 55G drum.
the new facility im building has a walk in freezer already, so i may prechill the barrel in the freezer, roll it over to the reactor, insert transfer dip tube, and pump and fill the reactor, atleast thats the goal
Edit: i feel like the prechill will reduce vapors in the pumping stage, which will make it safer, itll take more time to ramp temps up, but thats not a big deal. thoughts on prechilling solution before pumping? is this necessary? or waste of energy?
2 Likes
It’s not unheard of to keep the pentane in a chilled room and just pipe it from there to your equipment. If done right can make the safety inspectors happy too
4 Likes
hmm good idea, the layout of this building could facilitate a set up like that.
2 Likes