Hey all,

We're running SVO in an old Mercedes 300D.

We process the WVO as follows -- the waste oil is settled for extended periods of time, then it's heated and mixed with a bit of diesel, kerosene and other additives. While it's hot, we pump it thru 10 micron and 1 micron filters and the filtered fuel is then sent to the storage drum.

When we pump it out of the drum to fuel the car, it passes thru a waterblock goldenrod filter (10 micron I think). We've taken samples of this fuel when we fill the car -- the samples were put in 1 quart mason jars. The fuel looks good and we get zero precipitate even after the sample sits for a month.

The problem we are having is that we are plugging up the primary fuel filters faster and faster. We can now plug a filter in about 20 miles. Cutting open the used filters reveals an abundance of brown-black gunk. We've changed the feed and return fuel lines. There appear to be some really tiny cloth-covered rubber lines that go from the secondary filter and daisy chain to each if the injectors. Could this be the problem? Do these fuel tanks have an interior coating that could be failing? Perhaps something else I'm overlooking?

Any ideas for a solution would be most welcome. Thanks.

This message has been edited. Last edited by: rhinert,

Why do you heat the oil to filter it? What kind of filters do you use, and is the rating absolute? What do you do to remove water? Do you test for water content before blending? What is the system in the vehicle that you put this fuel into?

Sounds like animal fat or PHO. solution is to filter at temps below 65F. water is a different and very important issue. Water blocking filters do not work with VO.

We use a water heater and pumps to mix the WVO, kero and additives. We turn on the heat to make the mixing process more reactive. Sounds like we should try mixing cold or allow the mix to cool completely before pumping thru the filters.

The filters are bag filters that we order from industrial supply places like Grainger. I doubt they are absolute filters. We have homemade filter housings made from 6" pvc.

We have 'handled' water issues by long term settling. Sounds like we need to address this issue more diligently. From reading here, maybe we need to run the raw WVO thru a centrifuge? What is the cheapest rig we could buy or build?

We were running this thru a older Mercedes 300D with no modifications.

I see no problem heating the oil during the filtering process. I have been doing it for years, no issues. You don't describe your car heating system. Does your tank have a heat exchanger so that oil is heated too? If not, then you could be having a fat issue clogging the filters. If you have a heat exchanger and your oil is warm or hot, you may have a algae issue. The problem is getting worse because it is growing. Take the brown stuff, scrape it off into a spoon or small metal can and heat it slowly. Does it melt and return to oil? If so, probably fat, if not then it is something else. The daisy chain lines could be injector return lines, if so, they are not the problem.

There is no need to filter the oil after it is blended, except to "polish". The problem you have is fats and/or PHO. You have to filter the oil unblended at temps below 65F. If you settle it in cubies, you can just pour off the good oil and leave the fat. If you settle in a barrel, you are going to have some nasty clean up. If you cold filter the fat, you will clog your bags filters, and the pressure may force fat through the filters anyway. You might look up John Galt's upsettle method, depending on your climate. What is your climate?

You need not heat the oil and kero to blend unless you are in pretty cold weather. You can run such a blend in that vehicle, but you need to add at least a block heater, again, this depends on your climate. If you are in much of Africa, Central America, or the desert Southwest of the USA, OK. Any place else, this is going to cause problems, it is just a matter of when. Describe you situation in more detail.

We do settle the oil for over a month. Location is Florida.

We cut open an old filter today and collected some of the filter-clogging junk. Held a match to it and it "melted" and started to run down the cardboard it was collected on. It has to be fats coming out of solution.

The more I look at it, the more I think a centrifuge is the solution. I wish I could buy a cheap, effective unit at a reasonable price. I don't have time to spend hours researching this and handbuilding a solution ......

quote:

The more I look at it, the more I think a centrifuge is the solution.

Not unless you chill the mix, otherwise the fats will stay in solution and pass through the 'fuge, just like through filters..

quote:

Originally posted by rhinert:
We do settle the oil for over a month. Location is Florida.

We cut open an old filter today and collected some of the filter-clogging junk. Held a match to it and it "melted" and started to run down the cardboard it was collected on. It has to be fats coming out of solution.

The more I look at it, the more I think a centrifuge is the solution. I wish I could buy a cheap, effective unit at a reasonable price. I don't have time to spend hours researching this and handbuilding a solution ......

Your problem is very easy to fix....

1. Settle longer and make sure your settling tanks are out of the sun, preferably in the coolest place you can put them.
My oil gets settled a minimum of 3 months. I cold filter and dry it by evaporation through a jet of oil squirting back into the tank to aerate it. At the same time the oil is multipass filtering through a 5 UM bag and when it is dry it is pumped out through a 1 Um water filter.
I never have a problem with fats and last time I changed my filters I had put over 2500L through them and they looked like they could have gone at least 3 times more before they needed changing.

You don't have to complicate things or do anything different other than leave the oil alone longer. It dosen't get any cheaper than that either. If you can't do that, then cold filter it.


2. Hot filtering is the cause of your problem and is completely unnecessary.
The reason you are blocking filters quicker is because the weather in your parts is getting colder so more fats are falling out of suspension that the heating of the oil allowed to go through the filters. If you cold filter, the fats will get trapped in your filter bag, not in the car filters.
longer settling will allow more fats to drop out and the oil on the top to become clearer.

3. Do you have a HE in your system? If you put a HE before the filters, this will also eliminate the problem. I can run my 300D on pure liquid fats in winter. The fuel pump will pull them through the stock fuel lines and the fuel in the oem filter will allow the engine to warm up enough from dead cold before it blocks for the HE to melt the fats and let them pass through. Of course normally the engine is warm before I change over ( and I run a low blend in the main tank in winter anyway) but I have tested this a few times as an experiment and there has never been a problem ( even though I was expecting one!)

Veg will hold DISSOLVED water so don't expect it to settle to the bottom of a jar. It is dissolved so no matter how long you leave it, it will stay that way without some other outside force to cause it to drop out. Just because you don't see any water certainly doesn't mean it's not there, it just means you can't see it. I have tested oil that looked clear and shiny but still had a substantial water content. Your oil would have to be quite water logged in order for there to be enough to drop out for you to see. This should have happened in the settling process even if you do only leave it a month. Settling will reduce the amount of water in the oil but on it's own it will NOT ( in my experience) dry it unless you are in a very cold climate. My settled oil looks very clear but a hot pan test always shows some water ( even after 6+ months settling) which is why I set up the drying and filtering tank so both jobs are done in the one go and the process only requires about 10 Min of hands on time to dry 150L+.

ATM your process is creating and exacerbating the fats problem. Settle longer, cold filter and put a HE before your filters and you won't have any problem.
In fact, any 2 of these procedures would fix your current problem but all 3 is better and still easy to do.

That is the Simple, cheap and 100% effective solution that you don't have to research any more.