Recommendations for my WMO filtering centrifuge from the experts.

[giannid]

Hi, I'm new to the forum and am a contractor that has saved my waste oil from my trucks over the years and this winter I decided to build a centrifuge made up of parts I purchased locally and online. What I have is a dieselcrafraft oc50 centrifuge, Oberdorfer 1/3 hp gear pump, drum heating band from pa biodiesel, 100 micron strainers for pre filtering before the oil goes in the drum, thermostat in drum from pa diesel, some valves and gauges from home depot and a hot water pressure relief valve from home depot. I modified the drum, insulated it, and installed a bottom drain to drain and garbage from the bottom of the drum. Also, have it configured so I can pump the oil right into the trucks through a donaldson polishing filter. So my process is mix 35 gallons of waste motor oil with 10.5 gallons of diesel fuel, mix it for about an hour while heating it which is a 70/30 mix. Then I start to run it through the centrifuge and try to keep the oil between 140 to 180 degrees and 80 to 90 psi.. I shut the band heater off when it gets to 180 and that usually lets me filter it for awhile before I need to turn it on. It seems like the first day of filtering the oil I need to clean out the centrifuge twice as it got so gunked up on the first batch it stopped spinning. After the first day I clean the centrifuge one time a day. I've done 2 batches so far and the first batch I filtered for 4 days and the second one I filtered for 5 days. Is that normal or should I go longer or shorter? Seems like I'm still pulling contaminants out of the oil when I'm finished. I take it the centrifuge will always pull more out but when do you know when to stop? I have a 3 micron polishing filter and I figure that will get the rest out. I also let the oil sit for 24 hours to let the air out before using it. I ran two batches of it so far (90 gallons) in a 99 ford f800 dump truck with a 5.9 cummins in it. The truck seems to run a little better on it than regular diesel other than smoking a bit when it's idling. I have a tandem axle dump truck with an M11 cummins in it I'm going to try next but I'm thinking of a 50/50 mix in it. Is there anything else I should be doing? What is this coking of injectors I'm hearing about and is there anything I can do to help prevent it? The disease I'm mixing with it is a premium diesel fuel from a local supplier that is supposed to have soy and extra lubricity additives. We've always had good luck with there fuel. I'm in Ohio and plan on running the wmo only in the fair weather months. The trucks are both stock and no modifications have been made. ANy recommendations or comments would be appreciated. I also put an extra fuel filer with what I need to change it with in the truck I ran it in just in case. After 90 gallons no problems with the fuel filter yet. Thanks!

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[The FNG]

Sounds like you're on the right track with your setup. I do a little more pre-filtering, some do settling. Just know you made the right choice getting a centrifuge. As for time of filtration, I've asked the same question. It can be fairly obvious that in the beginning more sediment will be pulled than later on... Anyway, I have found with my batches that 3-4 days is enough. Mathematically, there will always be stuff to pull out. But that is what I have found to be sufficient for me. I have experimented on various times of centrifuging and it can take about 48 hrs to get the majority of the sediment out of the oil. I give it the extra time just to be certain. Some guys will debate and say that's over kill, but you will need to decide what makes you comfortable and how much you value your injectors. I recommend cleaning your centrifuge every 12-24 hrs and see what you find until you are satisfied with the results.

Coking is the buildup of carbon deposits from the slow-burning oil. It will prevent your injectors from having an efficient spray pattern and will cause smoking. I've found that it can be mitigated and managed, but not prevented. It seems that it will happen in time. Better filtration is one way to help mitigate this.

As for the diesel your mixing with, I might recommend using caution. There have been reports of issues mixing bio-based fuels with wmo. You may want to read up on that (just a note: you may want to shy away from the Jeffery Brooks stuff).


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[Brad S.]

Giannid, ditto on the setup, I'd say more advanced then alot of guys in the section.

The coking issue is something everyone that uses wmo fights at some level.
Just my own opinion, starting a diesel engine on regular diesel then switching/ to a wmo mixture, then before you reach a destination switch back to regular diesel.
But this type of setup requires some more equipment on the vehicle, usually additional tank or at least some 3 port valves to reroute the return fuel line.
Generally speaking as the temp goes down running wmo becomes a little more tricky..

 

[giannid]

I did some research before building this thing but honestly there's not a lot of information out there on wmo compared to wvo. I also am a contractor running trucks and equipment that make money so I'm obviously a little cautious on burning this stuff. Originally, I figured if I burned what I've accumulated over the years, it would pay for the centrifuge. I had almost 200 gallons of waste oil and it's about all burned considering each batch ends up only being 35 gallons of the actual drum as the rest is diesel and I never suck off the bottom 5 inches of the drum. My filtered batches end up being about 45 gallons with about 22% diesel to wmo which is about 35 gallons of oil to 10 gallons of diesel. The only truck I run the wmo in that rich is a cummins 5.9 in a ford f800 dump truck I have. I then turn it into a 50/50 mix to run in everything else. Filled up the tank in my 2001 7.3 powerstroke last batch and it seems to run good on it. Last batch I have brewing right now I added 7 gallons of rug to and 4 gallons of diesel to the 35 gallons of wmo. After 3 days of heating and filtering I'm down about 5 gallons in my drum. Seems like the rug is evaporating in the drum. Never happened with the diesel only mixes. Anyone else having this problems. I know gas is supposed to thin the wmo better that diesel, but if I'm going to loose most of it, it's really not worth it. Thinks I'm going to stick with blending with diesel and leave the gas for cars.

 

[AcIdBuRn02ZTS]

If the trucks get up to temperature quickly and see little idle time, then coking shouldn't be a huge issue. One of the nice things about running it in a larger truck is the load placed on the engine. The higher the load, the higher the EGTs which in turn burns the fuel more completely.

I ran into issues with coking with my 4bt but I blame that on the extremely short drives. In the grand scheme of things, it takes me about an hour to pull the injectors, clean the tips and reinstall. Only cost there is the copper crush washers... The best way to combat coking is to start and shutdown on straight pump diesel. A small tank and a couple valves and it could be done on the cheap. Also, I would say every few tanks to run a tank of straight diesel and run it good and hard.. that will also help a good bit.

If you are blending with gasoline then heating the oil, the gasoline will evaporate fairly quick. I would suggest either thinning with gasoline then centrifuging... or heat the straight oil while centrifuging... then mix the gasoline on the last pass without heat.

I didn't know people were running their centrifuges that long... I thought my 20hrs was overkill (and cleaning the bowl every 2 hours...)

Looks like I'll be upping my game a bit.

 

[giannid]

I'm going to be running this stuff in multiple truck so a two tank system is not an option. I'm probably going to be able to make a batch a week so it will be used on and off with regular diesel fuel so hopefully that will help keep the injectors clean. The trucks are all ran hard, especially the 5.9 cummins in a f800 dump as it's underpowered for the application. Only reason I filter for so long as I really never got a straight answer on how long to filter. I have come to the conclusion though it doesn't matter how long I filter, the fuge will still pull crap out. It doesn't bother me filtering for so long s I only really heat the oil for the first two days and that's only for a short time till I get the oil hot then I shut it off. I have the tank insulated well so I only heat it for a little while. The first day the fuge gets cleaned out twice in 24 hours, then I only clean one time a day after that.

 

[AcIdBuRn02ZTS]

Then I'd say your operation is fine...

I would still change up when you mix the gasoline/heat just to reduce evaporation.

 

[giannid]

I'm not loving the ideal of using gas. Think I'm just going to use a 80/20 blend in the 5.9 cummins and a 50/50/ blend in the other trucks/equipment. The 80/20 does smoke at idle quite a bit but runs well with the mix.

 

[AcIdBuRn02ZTS]

I would suggest looking at kerosene then... Diesel won't thin the oil nearly enough. The goal is matching the viscosity of d2 as closely as possible... RUG does this very well but has its downfalls.

 

[The FNG]

The thicker it gets and the colder gets, the more issues you will have. I suggest using RUG as it will reduce your issues moving forward. Remember, coking WILL happen, but it can be MITIGATED. I will leave the choice to you, but running mostly 15w-40 as fuel will cause hard starts and an ether dependence much quicker than you'd think (even in summer months). The idea of using RUG can be unsettling, but it is mostly necessary. Acid is correct about thinning...


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[giannid]

I'm probably not going to be using wmo in the winter months as our work is mostly exterior and we don't work much in the winter and I don't want to deal with the problems associated with it. You guys think thinning is even required at a 50/50 mix wmo to diesel? To me it seems like its not any thicker at that mix than d2. Maybe I'll try thinning again on the next batch with rug after I run the wmo through the centrifuge hot for a few days. After 2 or 3 days I shut the heat off and the oil is only about 100 degrees for the last day or two when filtering. Kerosene seems to be very expensive and I'm already running a dose of diesel clean in my wmo. I shouldn't have any problems with the rug evaporating at 100 degrees. You guys suggest 15% rug or more for final mix? I'm surprised that gets the wmo at such a low dose.

 

[Shadetreemechanic]

I avoid using RUG in anything that works hard. My guess is that it is volatilizing in the injection pump, but am not sure. I ran 80/20 WVO and RUG for several months in my john deere tractor, ford IDI and benzes. Towed a trailer with the benz in 90 degree weather and it quit on me an hour into the trip. All I could do to get it going was dilute what was in the tank with transmission fluid and d-2. With the John Deere it ran great until I put on the bush hog and worked it at full capacity. I got about an hour out of it and it gradually lost power and died. Again I just diluted the fuel and got it going again. Running light impliments or unloaded I never had any problems out of either vehicle. Never had issues with the IDI, but I didn't tow with an RUG blend.
I may try 5% or so RUG in the winter because it does tend to aid starting, but K-1 or D-2 seem to be much safer blenders.
Also I have been preblending and running the mix through my centrifuge without heat. It seems to work finend with my WVO it removes saturated fats much better when the oil is cooler.

 

[giannid]

Shadetreemechanic, are you strictly using wvo or have you used wmo also? Obviously the two act very differently. I don't plan on ever using wvo in my operation. Just wondering if the same apply to wmo and wvo. Thanks

 

[giannid]

I'm also wondering if using rug without alcohol ethanol may be the best. I have a local station that has real gas with none of the alcohol in it which is what your buying at all stations these days. The rug with alcohol in it is expensive though. I'm sure that could be a culprit to some of the problems people experience.

 

[The FNG]

I just had 3000# of oil in the bed of my f-250 and drove nearly 500 miles on my blend without a hiccup. My blend is W85 (15% RUG). Most of my oil is 15w-40, so I'm not sure how that relates to WVO. I think there is a bit of common sense and experimentation to figure out what works best for your rig. That being said, I still recommend blending with RUG even if you use a lower percentage. You could always blend 5% RUG and 10% diesel to start and see where that gets you.


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