Anyone have a suggestion for a vacuum pump for dewatering wvo?
Jon's killer rotary vane is probably hard to beat!!!
That baby is probably a very good fit with an MM500 push pull GL reactor!!!
Any condenser ideas?
Any new arguments about drying with vacuum?
Will Murphy soon offer plans for a MM 500 GL push pull reactor?
I got mine from a place that sells used meat processing equipment. It was used on a sausage machine to move the meat around by vacuum. I got it for next to nothing, after I took it all apart and cleaned out the meat and made new gaskets for it it worked like new!
Fuelfarmer said he is using a FPHE for a condenser with great results. He said he is going to get some pictures of it up to check out... Sounds like a good idea to me...
Simple schematic for a pump and heater control with a high limit
Sensor for the biodiesel/glycerin layer
I have converted both home garage sized air compressor pumps as well as York auto air conditioning pumps for use as vacuum pumps. these are piston pumps with one or two cylinders. The york is the easiest to adapt as it already has in/out fittings for hose or tubing but it is not too difficult to make up a flat plate to cover the intake port of the air compressor pumps so you have a place to add a fitting for the suction input.
Using these as vacuum pumps will pull a bit of lube oil out of there oil sump over time so you need to check the lube oil regularly (oil gets spit out of the exhaust of the pump). The York compressors are converted for use as on-vehicle air compressors by the off-road 4 X 4 folks and they have come up with verious ways to overcome the lube oil loss situation. This links to one of MANY web pages about modifying a YORK compressor for use as an air compressor, same idea works for vacuum, just make the connection to the suction side of the pump.
Good link...I'm exploring vacuum for reactor # 2...
It seems that there's a GL Reactor evolution happening...LOL
Are you condensing methanol/water efficiently enough and keeping those vapors out of the pump?
How are you cooling the condenser?
Is your inner condenser pipe crimped or coiled?
Do you consider these pumps very durable?
Jon is progressing on efficient vacuum pump dewatering/condensing...
Thanks for the link...
I don't make biodiesel, I run veg blend in my vehicle as well as for home heating, The vacuum pumps have been made up to use for WVO collection super sucker tanks, evacuating air conditioning systems, as well as for use in vacuum forming equipment. These piston pumps all have one or two rings on the pistons that keep any liquids from getting into the lube oil, since the cylinders are under vacuum a tiny bit of the lube oil will be drawn up past the rings and keep everything adequately lubed. Any liquid that gets drawn into the cylinders is simply expelled out of the exhaust port of the pump. I have even used both these type pumps as small water based steam engines so they can handle condensed liquids with no real problem. they are capable of pulling a lower vacuum than most simple Gast type sliding carbon vane type rotary vacuum pumps. These piston pumps use replacable thin metal flapper type reed valves (I have made these valves from feeler guages and steel shim stock) rather than mechanical positive sealing valves like used in an engine so even if some sort of an ignition happened in a cylinder the excess pressure should simply pass out through the exhaust flapper, probably scare the crap out of you but not likely to cause any damage.
The rotary vane Gast type vac pumps will also work pretty well, they also expel any liquids out the exhaust and will draw an adequate vac if you spin them fast enough, main thing is that when spun at high speed they are REALY noisy and the sliding vanes get gummed up by condensed veg vapor/droplets if used for collecting veg, they are easily cleaned but it is a nuisance. The piston pumps are pretty quiet and only make a sorta punkity - punkity lab vacuum pump sort of sound, they also do not need to run at high speed, most air compressor pumps are specked at around 1000 RPM max and are available in many different CFM sizes. Check with your local salvage yard for cheap air compressor pumps, I buy the single cylinder ones for $5.00 or $10.00 for the two cylinder ones. The salvage yard gets in probably 100/year from city folks and farmers, some are totally fine but got replaced because they are pretty cheap to buy new, others have pinholes in the air supply tank so won't hold air. the pinholes are easily fixed with epoxy, especially if used for vacuum, almost always the pump, motor, and controls are fine.
This links to an old sucker tank discussion that I put in the wrong forum, it has pictures of a Gast rotary pump that I made up and used for collecting (pictures may take a minute to recall), this was later replaced with one made from a single cylinder air compressor pump, I will post a picture of it if I can find one.
Pump location in condensing chain - I assumed any vac pump would be placed on the output of the collection tank and the input to the tank would be plumbed so that the tank worked as an aspiration type liquid/vapor seperator (input tube to the collection tank would run down well inside the tank so liquids were spit into the pool of liquid in the bottom of the tank rather than possibly being carried up and through the pump. There will still be some amount of vapor withdrawn out of the tank so I would seem to be wise to install some sort of liquid seperator between the output of the collection tank and the pump, something like a cheap air compressor centrifugal liquid seperator with a screw-in drain?).
A sealed frig compressor should also work for a good while if placed at the end of the line (other posters have said they use them) but these only move a VERY SMALL amount of vapor unless they are from a large 220 volt air conditioner, they also pass the vapor through there internal oil bath so they eventually fail do to there lube oil becoming contaminated, these are designed for intermittant use so will run hot if run continuously for more than say a half hour at a time, they are cheap enough to replace from a salvage yard though.
I recently had to service the brakes on my SKoda Felicia 1.6 diesel and removed and checked the vacuum pump. The Skoda uses the Volkswagen SD diesel engine used on early Golf/ rabbit cars. the vacuum pump is a really nice unit well constructed and reliable. I produces 10 psi at engine idling speed and more at higher speeds.
It would be fairly easy to mount to an electric motor using a length of rubber hose as a flexible coupling.
I'm hoping to get more input on vacuum dewatering and demething and to learn how to prevent distillate vapours from entering the pump...
Any facts available on the consequences of the water soluble contaminents left behind...the acids, salts, sugars...
I do a water wash of all my veg oil by adding a cubie of water to a barrel of oil, I also dissolve one pound of baking soda into the water prior to mixing it with the oil, the baking soda converts some (or all, depends on the state of the oil) of the FFA into soap and the water gets absorbed into the crud bits so they become heavy and drop to the bottom of the barrel over the next 2 week settling time.
All used veg has some water in it when collected and from observation I find that adding more water does NOT increase the amount of water in the final settled oil. The water also should wash out the bulk of any water soluble contaminants that was in the collected oil. The water ends up on the bottom of the barrel, the soap ends up as a layer on top of the water, the almost clean oil ends up above the soap layer. In the past I was dewatering the oil using an electric flash evaporator at the same time I circulated the settled oil through my filter setup, worked fine but the electricity needed to heat the 24 hour flash evaporation period was prohibitive. The filtering oil is heated to around 100 deg f as it circulates through the filter bank for at least 48 hours so I now simply spray the return oil from the filters back across the top of the heated oil barrel and let convection evaporation dry the oil. This process has been working well now for the last couple years.
Others use a water spray mist over the oil to extract the water soluble contaminants but I prefer mechanically mixing the water into the oil because of the baking soda I add. I have not read of any other method for removing the contaminants, most folks don't seem to do this extra wash step?
This links to a more detailed description of this cleaning process. It is a bit out of date and needs updating but I am still using the basic process.
It appears you intend to process the veg into biodiesel so you won't be doing the filtering step before the oil goes into the processor, is the slight reduction in yield due to the loss from the small amount of water creating soap actually worth all the time and energy needed for all the extra work in completely drying the oil? If you water wash the end biodiesel that should remove the contaminants that were in the original oil, the particulate should mostly drop out with the glycerin. If you intend to dry wash the biodiesel than I can only suggest water washing the oil as a first step in the process.
I appreciate your input...
Your flash evaporator seems the most impressive...
And water washing therefore has many benefits...