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A small electric flash evaporator to dewater WVO.
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Poor pictures -- Yep, camcorder captures. I can't seem to get the white balance correct to keep them from washing out, last ones were interlace also as I forgot to deinterlace them. These aren't much better unfortunatly, gona have to get a digital still camera I guess, looks a lot better as video.

5 ounces of condensed oil -- Yes the oil was condensed from the vapor being swept out of the flash chamber. If this is allowed to float off into the air with the water steam it condensed on everything in site, seems to especially like greasing up my windshield. I did not use the same "T" outlet pipe as is in the earlier picture. I added a 4 ft length of downwardly pointing 1 1/4 inch conduet, see "conduit" picture 3 posts below)

I have placed numbers on the attached poor quality deinterlaced picture, hopefully some discription will help, disregard the junk in the background, it is as organized as I get.

1 = the blue barrel is my filtering barrel, it is the supply for the wet oil.

2 = Hard to see but the silver thing is my prototype heating pipe, thermostat is to the left of the pipe. The heater pipe is wrapped in a couple inches of fiberglass insulation then covered with several layers of tinfoil.

3 = This is the small high-temp cintered brass in-line hydraulic filter (pictures of it earlier in this discussion). This has entirely ended the orifice plugging problem so far. This will eventualy need cleaning. Part of the test is to see how many cold starts I get before having to clean it. Seems the crud is baked oil flaking off the heater during warm-up.

4 = This is the newly added air input, I used a 1 inch pipe to allow the use of low pressure air at a low vollume. It's input is located just a bit above the internal splash plate. The idea is to pass an air flow across the flash area. The water-oil vapor is hot and wants to rise up in the flash tank. The outlet is on the opposite side of the tank and at the highest location, the vapor and added air rise up and flow out the outlet opening into some sort of condensing setup- yet to be deturmined.

5 = This is a small air pressure regulator to drop the compressed air down to just a slight flow at almost no pressure. This turned out to be a bit of a problem as the air flow would stop as the pressure in the compressor tank dropped. I had to set the regulator to flow more air than I would have liked to insure the flow did not stop. I intend to replace the compressed air with air from a small 4 inch muffin fan. The air will be prewarmed by passing it around the outside of the final vertical heater pipe, the threaded air inlet fitting on the flash tank will also serve to be the support for the final vertical heater pipe (see earlier pictures of the flash tank with proposed vertical heater pipe).

6 = This is the actual flash tank. I wrapped the tank in 3/8 inch closed cell plastic insulation, didn't have a choice about the blue color. Surpisingly the plastic did not melt. May be because the cross-flow of compressed air lowered the temp of oil collecting in the tank to between 170-185 deg f, depending if the heater was on or off. (wet input oil was about 100 deg f due to heating for filtering, outside temps were in the 40's f)

7 = this is the vapor outlet pipe. This is the first way I tried to condense the vapor. The tip of the pipe was placed first 1/4 inch then 2 inches below the surface of water in the cooking pot, didn't work. vapor bubbles simply quickly rose to the surface of the water without any detectable condensing taking place. The bubbles burst at the surface and released the oil-water vapor to rise up out of the pot and float away in the air.

Vapor in/out fittings are both made from a 1 inch pipe coupling that was cut in half and shaped to fit the side of the tank then brazed over a clearance hole in the tank.

8 = this is a piece of 3/8 copper tubing carring the dry oil off to be collected.

9 = This is a piece of 3/8 copper tubing running from a drain valve at the bottom of the flash tank.

Imageoverview-water_pot_setup_with_numbers.JPG (193 Kb, 310 downloads) initial flash tank condensing test
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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This picture is just a bit closer view of the flash tank and the air inlet and outlet pipes.

Imagecloser_view-air_inlet.JPG (225 Kb, 220 downloads)
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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This is a picture of bubbles rising through the water in the cooking pot, the vapor does not show up well, it sort of looks like density changes in the silver color of the sides of the pot. I tried a lot more water in the pot but it caused more pressure to be generated in the flash tank and caused the dry oil to rise up and run out the top of the vacuum-braker pipe just above the outlet shut-off ball valve. I also tried adding a cintered bronze air muffler to the end of the vapor outlet pipe in an attempt to brake the bubbles into much tinier bubbles, this also caused the internal pressure to increase and overflow the vacuum-braker pipe.

Imagebubbles_in_pot.JPG (142 Kb, 173 downloads)
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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This picture shows the 4 ft long downwardly pointing piece of conduit on the vapor outlet. This forces the vapor to float up along the top of the inside surface of the conduit insuring contact with the cold metal, water vapor still did not condense. The oil vapor did condense in the pipe and ever-so-slowly dripped out the bottom end. Took about 10 gallon of dewatering before any oil drops appeared at the end of the pipe. There was a continious flow of water steam rising from the conduet. (If you look close you can see dry oil dropping into the big funnel.)

Imagesetup_with_conduit_pipe_outlet.JPG (124 Kb, 225 downloads)
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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Thanks Tim, I don't feel nearly so bad about my messy clutter of barrels, filters, wires, hoses, etc Wink

Everything at home is frozen solid, and is likely to stay that way until warmer weather. The bucket of wvo I upended over the collection barrel is still solidly stuck in the bottom of the bucket after 2 weeks. I've taken the diesel off insurance and am now driving the petrol-powered car. To get to work requires burning about a gallon of gasoline that someone died for. Hard not to dwell on the implications.
 
Location: Moses Lake, WA, USA | Registered: August 15, 2001Reply With QuoteReport This Post
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Your wvo is fuel. Can you not burn some of it to heat the rest and carry on regardless? I just built a large shop burner and wish I had done it months ago.


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post



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Tim, once again thanks for the progress you have made for us all. I'm glad more people are reading the thread now it has been properly rated.


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post
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I started following this post last summer. It is wonderful to see it come through... Amazing work, Tim!
 
Registered: February 22, 2005Reply With QuoteReport This Post
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i do like the way you did this post but i was thinking today isnt there a way to build the setup to save on the cost of electricity to heat everything?
 
Registered: April 25, 2005Reply With QuoteReport This Post
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So, maybe I'm missing the boat, but wouldn't it be easier to just heat a 55 gallon drum full of oil much the same way a fryer does and wait for it to stop popping? Just leave the small bung open to vent pressure. Once your above about 275 if there's any water it'll be entertaining to listen to....and safe as long as you are protected from the splatter. In other words you're doing a really huge frying pan test. A small stream could be pumped if you have a concern of suspended water.
 
Registered: January 24, 2006Reply With QuoteReport This Post
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Welcome to the forum Steve,


Boiling water out of a drum ov wvo is nearly impossible for several reasons. it has been discussed often on the forum previously. It is very wateful of energy..and tend to leave a lot of water in since the temp of the oil varies enough to allow water vaporized on the bottom to condensin while still in the oil before it escaped at the surface.

And boiling tends to leave a LOT of suspended wate rwhich must be removed some other way. Mushc eassier to just use a more effective water removal method in the first place.
quote:
Originally posted by Stevonator:
So, maybe I'm missing the boat, but wouldn't it be easier to just heat a 55 gallon drum full of oil much the same way a fryer does and wait for it to stop popping? Just leave the small bung open to vent pressure. Once your above about 275 if there's any water it'll be entertaining to listen to....and safe as long as you are protected from the splatter. In other words you're doing a really huge frying pan test. A small stream could be pumped if you have a concern of suspended water.
 
Location: Central MN..Brrrrrr! | Registered: November 06, 2001Reply With QuoteReport This Post
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Tim,
Any update on this project?

heavily interested in mobile dewatering,
Rob
 
Registered: January 26, 2006Reply With QuoteReport This Post



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Still a bit too cold to work outside, just doing paper ideas now. Will be trying a different steam condensing scheme eventualy and installing a permanent 1 or 2 heatpipe setup to hold the heating at or below the current 60 watts/sq inch to keep from burning the oil. Here is another discussion with a bit of info on ideas about heat density and using glowplugs to heat a mobile dewatering setup.
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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Tim what would you say for or agains the idea of using a diesel vehicle injection pump as a way to get the oil into a fine mist in a Flas Evaporator. I have an extra IP and was thinking about driving it with an Electric Motor.


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Location: North Tx | Registered: November 23, 2002Reply With QuoteReport This Post
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Injector pump -- Without thinking this over much yet, doesn't seem to fit the requirements to well. Pressures come in several thousand pound high pressure pulses rather than a steady 150 pounds pressure. I intend to try using an oil feed pump from a standard home furnace oil burner unit, these have internal pressure adjustments that can be set anywhere from 100 to 200 pounds output pressure. These are about the size of a baseball and the standard motor is usualy 1/6 HP, this motor also powers a blower so it should take even less to run just the pump. The standard 1750 rpm pump (higher speed allowed, could turn it with a 12 volt DC motor) will flow up to about 3 G/H and the 3500 rpm unit flows up to about 7 G/H. they are available with even much higher flow rates. These are available on ebay for usualy under $35.00. Suntec pump page is here.

I also want to try to change the pressure spring in one of these small pumps and see if it will make a reliable 5 to 15 pound pressure vegoil fuel lift pump. The flowrate table shown on the web page seems to indicate that even the 3 G/H pump will actualy flow up to 7-8 G/H ?
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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this is cool! just found it. my suggestion to control the pressure is a variable speed dc motor driving a small gear pump, like the oil furnace pumps. the orifice size can be fixed. faster pump speed- more oil flow, lower temp, higher pressure. slow it down just a bit to raise the temp to what you want. dc motors availble from grainger- gear pumps too.

have you worked on this more? probably needs a low level shutoff if run unattended.

good work!

pat


quote:
Originally posted by Tim c cook:
I recently tried several dewatering techniques, Heat-and-let-settle, Spray hot oil through the air, electric frypan. None did what I wanted. All these require that the oil go round-and-round til it may finaly be dry ( high humidity in illinois never did let it get really dry). you have to keep testing the oil and run the process for however long it takes, I wanted to run the oil through a process once and be assured it was dry. -- FOUND IT .. FLASH EVAPORATION ...With this method you pump cold, wet oil into the heater and get absolutly dry, hot oil out.

This dry oil can then be collected into a separate container and immediately used, no waiting for the entire batch to get dry and no testing needed. It does take a bit of electricity, I figure around 2 cents per gallon on my prototype but I was not recovering any of the heat with it, the new unit will pre-heat the incoming wet oil by running it through tubing emersed in the outgoing hot condensed steam (around 200 deg F) and hot (300 degree f) oil. Everything will get wrapped in insulation. I think this will recover at least 1/2 the heat so the additional heat should only cost about 1 cent/gallon.

In the "sugar in WVO" thread (here,2nd and 5th posts down) Magnito describes his large flash evaporator, it does around 5 gallon a minute, my small unit does about 2 gallon/hour. His evaporater is a modified pressure type oil fired steam genny. This is way bigger than I need ( only need a couple gallons per hour if it can run unattended 24 hours/day) and his big unit has to be monitored continuously. I came up with a small version using an 1100 watt electric water heater element for the heat and a 12 volt shurflo RV pump to pressurise the oil to 90-150 pounds to keep the water from boiling inside the heater pipe, flow rate is about 2 1/2 gallon/hour.

The pressurized wet oil is heated by the water heater element inside a 12 inch long piece of 1 inch pipe, the heater is screwed into a "T" on one end of the pipe, the oil is input into the side of this same "T", the 300 degree hot,wet oil comes out the other end of the pipe through some sort of small oriface, the water immediately flashes off into steam due to the reduction in pressure. I initially used a ball valve as an orifice and sprayed the oil/steam into a cooking pot. This works (I dewatered 25 gallon this way, absolutely NO bubbles seen, not one, using the "frypan bubble test") but there is a fair amount of oil vapor that drifts off with the steam, it condenses on everything in sight , it also is a big fire hazard. I am now working on the next generation that uses a fixed size orifice from a oil fired furnace burner unit and sprays the hot oil/steam into a couple of small tanks (2 quart),the first tank seperates the steam from the oil, then the steam-with-oil-vapor goes into a second tank where the steam is condensed into water and the oil vapor is condensed back to liquid oil, the oil floats on the water so they can easily be seperated using a gooseneck grease-trap type method.

The flow through this unit is a balance between heat, pressure and flow rate. You want to keep the oil temp at around 300 deg f so if you add more heat you need to increase the flow rare linearly, twice the heat = twice the gallons/hour etc, as long as the pump can hold the pressure you can build the unit to dry what ever gallon/hour you want.

I am using a shurflo rv pump for the pressure. I was amazed that these pumps will create way over 150 pounds pressure (and survive, at least so far). I adjusted the pressure cutoff switch to 150 pounds and the pump cycles off at 150 pounds and back on at 90 pounds. I am working on a pulse width modulated electronic motor control for the shurflo pump that will hold a more constant pressure. You could also use a fueloil pump from an oil fired furnace burner, it does this exact same job on the oil burner.

On the prototype I ran the heater continuously and controlled the oil temp by slightly opening/closing the ball valve. This works but you have to tweek it every few seconds. On the new unit I am using a constant flow burner orifice and will use a thermostat to control the heater, this way the unit will run without needing to be watched or tweeked.

I think this unit can be reduced to fit in the space of less than one cubic foot. It also could be built to run entirely on 12 volt DC power for mobile dewatering

Here is a picture of the prototype dewatering oil. The steam can sorta be seen as lighter patches floating away from the pot, hard to see in a still pic.
 
Registered: January 15, 2006Reply With QuoteReport This Post
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Anything else to add to this very solid work Tim?


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post
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OK - Warm weather is finally here and I have dried a few barrels of oil again this spring. No big updates but several small problems and improvements.

Pumps -- I have been using a shurflo RV 1.8 G/M water pump for all but the latest barrel of oil. The shurflo has worked well, the electric motor has run warm enough that you did not want to hold your hand on it for more than about half a second and still keeps on running, no electrical problems with the motor. The actual pump housing is plastic and the internal design of the pump uses 3 small plastic diaphragms. Because of the diaphragms the pump creates pressure pulses, this causes a pressure guage to girate a good bit and it also will cause the pump housing screws to loosen a bit when running it at over a hundred pounds pressure over long periods while filtering oil. The pump would develop a drip after running continuously for several days, no real problem, simply tighten the screws. -BUT- 120 to 150 pounds pressure is a lot more than the normal shurflo pump is designed for and a couple of problems associated with the pressure shutoff switch have shown up over time.

The following picture is of the basic shurflo pump type that I am using.

Imagestandard_shurflo_pump_2_.JPG (34 Kb, 98 downloads)
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post



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The first problem is with the actual electrical switch that is used in the pump. The switch is located in the plastic section on the very front of the pump, the switch itself is an industry standard " microswitch" type switch. It can be replaced by removing the 3 center screws on the switch housing and prying the plastic snap tabs open to expose the switch

Mechanical switches are only designed to operate for a few tens of thousands of times before something gives up so this switch gets a workout on my filter setup when the filters get clogged and the pressure reaches the set point, the pump may turn on/off every second, depends on how fast the oil is seeping through the filters. this action has caused me to replace the switch a couple times over the last couple years, again, no big deal, luckily it has always failed in a manner that has shut the pump off so nothing has gotten over pressurized.

This picture is a closer view of the switch housing.

Imagepump_switch_assembly_cu_1_.JPG (27 Kb, 75 downloads)
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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A caution about removing the pressure switch unit. There is a plastic diaphragm located under it that has a spring and a check valve behind it, these parts will jump out as you pull the switch housing away from the pump.

This picture is of the diaphragm and the parts located behind it.

Imageck_valve_parts_4__.JPG (23 Kb, 80 downloads)
 
Location: fisher,illinois,usa | Registered: June 03, 2003Reply With QuoteReport This Post
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