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A small electric flash evaporator to dewater WVO.

This topic can be found at:
http://biodiesel.infopop.cc/eve/forums/a/tpc/f/159605551/m/352100169

September 25, 2007, 03:02 AM
Tim c cook
A small electric flash evaporator to dewater WVO.
philman -- About your drying and nozzle questions, I think you are mixing up the drying of finished biodiesel with this discussions topic of drying only vegoil, not biodiesel. This flash evaporator is a design for drying only oil, not the more volital biodiesel

That said, the reason they dry biodiesel is because they wash it with water after the biodiesel making process to remove any left-over alcohol and also to wash out any soap that got made during the biodiesel process. after the water washing, the bulk of the water and any alcohol and soap that the water contains, is drawn off the bottom of the tank after letting everything settle for a time. The remaining hot - wet biodiesel is then sprayed from the spray nozzle as a fine mist through the air and the hot water vapor is released into the air, being hot vapor, it moves up and out of the open top of the drying tank while the hot oil just falls back into the tank. This is the same basic concept as the flash evaporator, but the FE runs a good bit hotter and under much higher pressure as the thicker oil won't let go of it's water as easily as the much thinner biodiesel. I have tried simply spraying hot oil through the air, all it did was make a mess on my driveway and the oil never did get dry, even after doing this for 5 days.

My FE flash tank is about 5 1/2 inches in diameter and 15 inches tall, the heated and pressurized oil/water enters down through the removable top assembly, through the orifice, then squirts on to a solid 1/8 inch thick, 3 inch diameter plate located 3 inches below the outlet of the orifice, the plate is tilted at a 45 degree angle. Bashing the high-speed jet of oil/water into something solid helps liberate the water.

I have a small air blower mounted through the side of the flash tank, this air comes into the tank a couple inches lower than the bash plate, flows across and up the inside of the tank and exits out of another opening on the opposite side of the tank, up next to the closed top of the tank. The added air, plus the fact that hot steam rises, sweeps all the vapor out of the flash tank, the hot/dry oil stays inside the bottom portion of the tank and then runs back in to the filtering barrel.

The water vapors exiting the tank also include a bit of vaporized oil, this oil floats all over the neighborhood and leaves an oily film on everything it touches, cars, house windows etc, lukily my neighbors never figured out what was causing this -SO- I added an air cooled oil condensing tank on the end of the output opening, the hot water/oil vapor exits the flash tank, then flows up inside the condensing tank (BBQ sized propane tank), the vapors hit the inside top of the tank, the oil condenses and runs down the inside wall, then drips out a couple 1/8 inch holes in the plumbing at the bottom of the tank. There is a smaller diameter tube running up the center of the condensing tank, the top of this tube stays inside the tank and ends a couple inches below the inside top of the condensing tank, the bottom of this tube runs out below the condensing tank, and is open to the air. the water vapor does not condense on the internal tank wall but flows down through the center exit tube and excapes into the air as water vapor. Sometimes this water vapor is visable if the weather conditions are just right but usually it is only visable as wavy air currents like make up a desert mirage.

There are pictures and a description of the flash tank and condensing tank on page 8 of this discussion, starting just a bit more than half way down the page. These pictures don't show the small air blower as I was using compressed air at the time the pictures were taken, but the tiny 12 volt 3 inch diameter squirl cage type blower blows it's air into the flash tank through the same 1 inch pipe that is visable on the left side of the flash tank.


PerkHouse -- Pump motor -- This is a salvaged electric sidewalk scooter motor, available on Ebay for from $5 to $15.00 usually. Nice motors, all ball bearings, and big enough and well built enough that they hardly get warm with 12 volts. I have run this motor for well over a year with no problem. It is rated at 24 volts, 350 watts (this is about 1/2 HP) when powered with 24 volts. Powering it with 12 volts it can safely make up to at least 1/6 HP (totaly depends on how hot it gets) but the pump only takes about 1/30 hp to turn even when making 160 pounds pressure. I measured the amps being drawn and it is less than 3 amps at 12 volts when making 165 pounds pressure, less as the pressure is reduced. The motor turns the pump at 1600 RPM when powerd with 12 volts, the smaller flow rated 3400 RPM rated pump I am using is a bit worn internally after 3-4 years of 30-40 hours a week use so leaks a bit of pressure past the back of the gears, I need to turn it faster to make more pressure. I have a 2400 RPM motor from a worn-out Shurflo pump unit, I will try that on this pump and see if I get more pressure. The Suntec pumps are stated to be able to make at least 200 pounds pressure depending on the RPM and the flow rate. I have picked up a couple 1725 RPM rated versions of the same pump, these have a larger gear set and will move 60% more oil for the same rpm, I will be testing flow rates on these larger flow pumps, may be that I can use the same 1600 RPM scooter motor on the larger flow pump and it will make some higher pressure, tests will tell.
October 15, 2007, 09:37 PM
PerkHouse
I've got an issue that maybe you can help me with. I've never resolved it. (I first noticed it a year ago.) When trying to flush my system with kerosene, my pressure drops to zero. Since these pumps are made for fuel oil, shouldn't they pump the lighter viscosity kerosene? Could the problem be the modification I (we) did to make it run at the lower speed? What else could it be?

VO runs at 170 psi; K1 runs at 0 psi. What's up with that?


Brian

2000 Jetta TDI
1982 Mercedes 300D Turbo
1986 Isuzu P'up (NA)
1985 Mercedes 300D Turbo
75/25 WVO/D2 for warm weather
50/50 WVO/D2 for cold weather
Uniqueness is a treasure not to be buried. - Laurence Martel
October 16, 2007, 02:22 AM
Tim c cook
Perk -- I think you had a similar situation when first testing your 2-stage suntec pump.

Testing my single stage pumps I find a bit of a drop in pressure with thinner fluid, I suspect this is caused by the thinner fluid being able to more easily bypass the gears due to the pump having a good bit of wear that has increased the clearances on the sides of the gears and the gear chamber. The pressure never completely drops to "0" but it will drop below the 40 pounds it takes to keep the low pressure safty switch from tripping off.

I don't think the mods would have any direct effect and cause the complete loss of pressure.

One possibility, if you are still using the 2-stage pump. The picture attached at the bottom of this post shows the flow diagram of a model "B" 2-stage pump (disregard the two-step referance). It shows the fluid inlet for the lower set of gears as being at the bottom of the fuel cover fuel chamber, this oil is only used to lube the shaft seal and the gears create no pressure at all as the flow is returned directly back to the fuel chamber in cover of the pump. The upper set of gears is what actually is used to make the pressure and flow, The inlets for this set of gears are located a bit over half way up the columb of oil in the cover. I wonder if somehow the lower gear set is pulling enough oil out of the cover chamber to uncover the oil inlets to the top gear set, the top gears would then suck air and loose all pressure. The lower gear oil should be recirculating back to the cover chamber unless you are sending it back to the supply tank, if it is being recirculated into the cover chamber then the oil level in the chamber should stay high enough to feed the top gear set, don't know where elso to look.

I don't yet have a 2-stage pump to look at or test, been intending to get one to try modifying it so I can use the 2 gear sets independently, one to make pressure for a burner nozzle, the other to use as the feed pump for the gear set that is feeding the burner nozzle, the second gear set will pull oil from the big fuel supply tank and keep the cover fuel chamber full for the other set of gears to pull from, the babington nozzle excess fuel return will run back into the cover chamber under gravity.


October 16, 2007, 07:08 AM
PerkHouse
Actually, I am returning the return line back to the supply, so maybe if I change the orientation of the pump it will work with both fluids. Right now, it's vertical: the motor is shaft up and the pump is shaft down.

Maybe I should re-mount it horizontally instead of vertically. I know the instructions say there is only one orientation that will not work, but an engineer at SunTec told me that any orientation will work. Maybe I found one that won't??? Wink


Brian

2000 Jetta TDI
1982 Mercedes 300D Turbo
1986 Isuzu P'up (NA)
1985 Mercedes 300D Turbo
75/25 WVO/D2 for warm weather
50/50 WVO/D2 for cold weather
Uniqueness is a treasure not to be buried. - Laurence Martel
March 23, 2008, 01:41 PM
frydaddy
what are u using as a mister head at the exit into the dewatered holding container? Can you post some more pics of your flash evaporator, I see the tee where the elec. element is and the exit, but I do not see where the oil enters.
March 23, 2008, 02:35 PM
Tim c cook
The oil entered into the side of the "T" on the bottom of the heater pipe.

The oriface I am using is available from McMaster-car, the style I am using is basically a pipe plug that has been drilled with a tiny calibrated .o18 straight-drilled hole through the center of it, this gives a flow of 5 1/4 gallons/hour. A home furnace oil burner nozzle could also be used by removing it's easily removable internal spray insert, the insert makes the nozzle create a fog but by removing it you end up with a straight hole through the front portion of the nozzle, only problem is they use an odd thread for mounting so you have to either buy a furnace burner nozzle adapter or buy the correct threading tap to rethread a pipe fitting.

I had a failure in my temp controller last fall and the heater was turned on continuously for about 12 hours, made a good bit of a mess by loading the entire unit with crusty oil, been too cold to rework the unit til now so I will be cleaning it up in the near future, adding a cheap $35.00 Ebay temp controller, and also moving up to a .o23 orifice, this should up the flow to closer to 10 G/H. The higher flow rate will likely keep the heater turned on 100% of the time for the first several hours til the entire barrel heats up, not a problem as I now only heat the oil through the evaporator to around 230-250 degrees to keep from causing the polimerization that happens when running it at 350 deg f. Yhe lower temp does not do a complete one-pass dewatering of really wet oil so I now let the eveporator run for the entire 3 days that I circulate the oil through the filters so no time is lost.

Once I get the unit up and running again I will post some pics. I want to rework it a bit by mounting it slightly off to the side of the filter barrel rather than settin on the plywood top of the barrel, getting tired of moving it every time I want to open the barrel.

Still intend to switch to a centrifuge eventually, It will cut my filter/dewater time from 3 days to only a few hours, and reduce the electricity cost of cleaning 50 gallons of oil down from around $8.50 to under a dollar.
April 11, 2008, 09:19 PM
frydaddy
what all do i need to make flash evaporator? I was told a power steering pump and an electric motor. piping and an electric water heater or two, and a thermostat. If i could get a few pics and some good advice i would much appreciate it
April 12, 2008, 01:04 AM
Tim c cook
The only pictures I have of the verious parts are scattered throughout the early part of this discussion, they are poor pics as they were captured from video, unfortunatly I caught a computer virus that wiped out all the registeries on my computer hard drive and I lost even these poor pics.

I still have not cleaned and repaired my unit after the temp controller failed so don't have even current pics.
Now that the weather is getting better I will be disassembling the unit to clean it up and get it back in service, I now have a digital still camera so I will take pics again and post them here, probably should put a "Synopsis" page at the front of the discussion like Sunwizard did for his centrifuge thread.
April 12, 2008, 09:29 PM
frydaddy
thanks for replying, i just put tags on my mercedes 300 td. I am trying to set up a system to clean and dry my oil. I am using filter bags for now, they are 1 micron but i am not sure if they are absolute. On my rabbit i am using a parker racor 900 filter water seperator with electric heating element. what is your opinion on those, do those filters really block water? My rabbit has done fairly well except for a glow plug incident and fuel milage loss. I have been told injectors are probably malfunctioning. I appreciate all your help and look forward to seeing your new setup so i can build one. thanks again
frydaddy
July 28, 2008, 08:43 PM
Tony Vickers
Tim --Wondering if there was any updates to your rig you could share


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June 28, 2009, 08:57 PM
philman692000
i was wondering how you been doing are you still useing your FE i was thinking of building one so i was reading your post again my CF is not keeping up with oil drying its taking about 7 hrs to dry oil ! any updates ?


avoid paying the man
June 29, 2009, 12:22 AM
Tim c cook
I am just now getting around to cleaning oil again this summer, just stockpiled the oil over the winter. I had a failure of my temp controller last fall, this turned the heater full-on and I didn't catch it until the next day. This filled the heater pipe and the 1 gallon collection tank with crispies, it also burnt the paint off of everything. I will be rebuilding the setup sometime soon and intend to up the flow rate to 10 G/H by increasing the diameter of the orifice by 50%, I may also have to move up to the larger flow rate 1750 RPM rated Suntec oil burner pump to be able to supply the 150 pounds pressure at this higher flow rate, won't know for sure til I get it all back together and try it out. Rough calculations and past testing indicate that the existing 1125 watts of heat should be about right to keep this higher flow rate in the 250 deg f range if it runs full time but I will have to test this. I will post pictures of the rebuild.
May 07, 2010, 05:03 AM
evergreen
Well here is just an Idea ,what about a solar water heater with a small hole at the top to alow steam to escape .The generate plenty of heat even in mild weather .Direct sunlight is all you would need .They are expensive but wont need replacing and it is free energy someting we all like
April 21, 2011, 04:07 AM
Tim c cook
Just read back through this discussion and now see that I never actually brought my testing to a close. I was asked if I was still using the FE to dry oil in another short FE discussion dated April 2011, the following is a copy of the answer I gave there -

I have stopped using the FE for a few reasons. To get totally dry oil in one pass I needed to run the temp up around the 350 deg f point but at this temperature you create a lot of polymerization on the inside surface of the heater pipe and the plumbing going to the orifice, bits of this plasticized material would break off and plug up the tiny orifice opening, I got tired of burning the begeses out of my fingers unscrewing and cleaning the hot pipe plug orifice. The polymerization goes away if you run the temp down around 250 deg f but you then have to recycle the oil through the unit several times to insure it is dry, either way it takes a good bit of electricity to do the extra heating, this was adding about $5.00 to the cost of each 50 gallon barrel of cleaned oil, the extra 10 cents/gallon is just something I would rather not have to pay.

Somewhere on the biodiesel side of the forum I read of a setup being used for drying biodiesel by injecting a high speed stream of the biodiesel back into the top of the open topped dryer tank such that the stream was directed directly down into the top of the biodiesel, this high speed stream draws a LOT of air with it by venturie action as the stream impacts and drives through the surface of the bulk fluid, the air then spreads out under the surface of the oil and rises as bubbles that break on the surface and release the water vapor. This required passing the oil through more than once but so did the FE when run at the lower temp. I heat my settling and filtering barrels to 100 deg f and re-circulate the oil continuously through the filters for 48-72 hours anyway so by adding some plumbing I was able to do this same "venturie" thing with the oil out of the last filter, this has worked fine for the last couple years even in the more humid Illinois weather, it works GREAT in the less than 10% Arizona humidity. I do have to change filters a bit more often than before adding the venturie to keep the flow through the filters high enough to produce a high speed stream out of the 1/4 inch hose barb that I have screwed onto the end of the 1/2 inch pipe plumbing. The 1/4 inch hose barb restriction has an internal diameter of 3/16 inch and works to increase the stream velocity high enough to draw plenty of air down under the surface of the oil. With the heated oil I can actually see the water vapor rising out of the top of the open topped barrel for the first several hours, or up to a day, after that enough water has been removed that the vapor is no longer visible, I just let the setup circulate the warm oil unattended for the total cleaning/drying period of 2-3 days, this eliminates the added electricity cost, and the burnt fingers, and I still end up with nice clean dry oil.

Thanks to everyone who participated in the development of small flash Evaporators and for all the info they added to this discussion - Thanks - Tim

(I forgot all about doing more testing using low temp/high pressure, this may still be usable as a dewatering approach for a mobile dewatering setup.)
April 22, 2011, 06:46 AM
CraigCurtin
Hey Tim,

Wondering if you could post a link to that discussion you found (i cant find it) about drying BIO/OIL with the new setup ?

I am both a WVO user and also a BIO maker and would like a better way of drying both

Craig
April 24, 2011, 12:06 AM
Tim c cook
Don't have a clue now, the post had to be from well over two years ago now, there was a picture but it was from an off site web page, did you check the archives?

Finding old discussions is a chore, been trying to find one of my own old posts for a couple weeks now, still nothing.
May 03, 2011, 10:19 AM
gaval1988
i find this peace of information very useful, i tried several dewatering techniques and this one is great. good work and more power men!


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