Oil settling

[Guest Close David]

This evening I decided to enjoy the fading light by doing a bit of oil filtering in preparation for some running round this coming weekend.

I grabbed a new filter and a drum of oil straight from the chip shop and pumped it through with my little pump. The oil looked the same coming out as it did going in which was a beautifully clear light tan colour. After about 16L the filter looked no different and was flowing the same as when I started.

To top off the 25L drum I was filtering into, I went over to a 200L drum I have had settling for about 6 weeks and started pumping off the top of that. Within 4-5 Litres, the flow was right down and the filter looked dirty. This oil came from the same place I get all my oil and I remember the drums I put in all looked pretty clear oil and I don't pour all the dregs or fat in.

I backwashed the filter a couple of times with filtered oil into a slops bucket but still the filter would clog again quickly. Getting the 25L drum topped up was a real effort.

I am wondering what could have caused the oil that has been settling so long to block the filter so quick?
The drum is of the blue plastic variety and sits in the sun most of the day. The oil felt quite warm and seemed to flow easily before the filter clogged.
It appears clear as it always is but there is something clagging the filter.

Should the drum be left in the shade instead of the sun?
Could the 40o day we had here yesterday have stirred the drum up by some sort of thermal convection?

If this oil is going to block up filters in under 10L, I'll just have to earmark it for bio production but something seems odd because out of the probably 1500L I have got from this one supplier, I have never had oil block a filter like this especially when it has been settling for a month! The oil that went into this drum was a random selection of drums that had probably been collected over a couple of months so I have no concerns I used a bad " batch" of oil because it is all a mix the same as the other drums I have settling that have been no trouble.

Any suggestions on courses of action or what to look for to diagnose what is up with this particular drum of oil?

[zigparacingtadpole Senior Member Find all posts View Profile Close zigparacingtadpole]

Re: Oil settling

G'day David,

The first question that springs to my mind is the depth of the pick-up for the pump.
If the oil was a bit dirty, or more heavily used than normal, then the particulate and contaminants sink to the bottom usually. Drop the pick up into the bottom and suddenly everything becomes so much more painful.

I have just begun using a drum that has been sitting for several months, if I tap off the top the oil looks really good, tap it off the bottom and you'll NEVER eat fried food EVER again. I get one of my kids, or my missus to hold the pick-up hose just under the surface to try and avoid the crud on the bottom (also notice that I am smart and dont hold the hose myself, hence dont get covered in the stuff, like they always seem too ).

I tend to agree with your idea of putting it aside to make bio out of it.

[Guest Close David]

Re: Oil settling

Hi Adam,

The pickup tube for the pump never went more than about 4 inches under the surface of the full 200L drum. Certainly the oil is clear and bright and nothing like the crud that settles out to the bottom. There was no wisps of fat I could see going in or that came out the filter when I backwashed it.

I have settled out oil like this before in an identical drum right near this lot and had no troubles. I have 5x 60L drums settling that are under cover so I will check those today and see what the oil in them is like.

When I dipped the top of this oil, it looked so clean I wondered if it was even worthwhile filtering it. I certainly have my answer now.

I thought I might run some clean hot oil through this filter and see if that frees it up. If it does I'll at least know what is causing the problem.

[Fitian Was here Find all posts View Profile Close Fitian]

Re: Oil settling

David,

I believe these filters are not coping with your demand. They are not made for oil to start with. I just managed to get half a meter of the 5 micron filter bag material. I can share some of it with you and you can make a fram or holder for it. You will filter your oil faster and better this way.

Cheers,

Fitian

[zigparacingtadpole Senior Member Find all posts View Profile Close zigparacingtadpole]

Re: Oil settling

Hmm, thats a bit odd then. What sort of filter are you using? Have you used this drum before?If not, is it possible the drum was contaminated? Am I correct in assuming that you are not applying any heat during this process? Did you by any chance take a temperature reading of the oil in question? Have you tried a titration on it? Sorry to bombard you with dumb questions but I am just trying to paint a mental picture of your problem.

Right at the moment the only thing that springs to mind is that your theory about the heat is correct, or that it has started to breakdown and filtering is removing the broken bits if that makes any sense.

[Guest Close David]

Re: Oil settling

Hey Adam,

I *think* I have the Mystery solved.
I tried the oil again today and straight away I could see the flow coming out of the filter diminishing by the second. I cleaned the filter again and tried it on some other primo oil I have settling and the same thing happened although not quite as bad. I noticed by this stage the filter element was collapsing quite bady. Then the penny dropped.
The one obvious factor I overlooked in my ignorance was the fact that I was using a different brand of filter to what I normally use.

My complex filtering system consists of settling the oil and then filtering it through those disposable inline type filters that I normally get from supercheapo. I saw some at another place and thought they might be better. Having run out of the supercheapo type, I put one of these on the end of my pump. Obviously despite being more than twice the price, they aren't up to the job.

I did wash the filter out again and then reversed the flow so the pressure was expanding it rather than colapsing the element and it seemed much better. Only trouble here is that the pores of the filter medium may also be expanding letting through more dirt.
Easy soloution is just go back to the cheaper filters till I get myself organised and set a up a proper system.

I have been putting this off a bit as I am in 3 minds which way is the best to go as far as bang for the buck in filtering cost, effectiveness and making the least mess possible. I have been contemplating using a CAV filter, a water type filter or a bag filter.
In reality I am probably not filtering enough oil to make much difference cost wise so maybe I should just set something up and be done with it.

I'll get some more of the usual filters and if they block up as well, I'll just give this drum of oil to a needy Bio maker.

Fitian you are right about these filters. Normally I get around 150L through them and then I backwash them and get at least another 50L out of them. For the amount of oil I use, this has been pretty adequate so far.
I use the same filters on the car and they only needing changing every 6 weeks or so and when I remove them, they appear to be getting blocked from the black gunk that is still coming from the fuel lines and maybe IP. I'm very fussy with the oil I put in the tanks and I know they don't have any of this stringy black goop in them when they go in. I sometimes find it in the bottom of the empty drums I take out so I know it is coming out of the fuel system rather than the oil.

I would be interested in a small piece of your filter material to try. I know you have your own oil refinery going and half a meter isn't much to be cutting up so don't worry if you need it. If you can source more of this stuff, I'd be interested in buying some with you. Would be easy to make up a frame or sew it into bags. I have an industrial sewing machine up the back ( actually 2 I think?) so making up some bags wouldn't be hard at all once I excavate the machine from out of the shed.

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Oil settling

I have used the following for filters.
stainless pickup strainer from a hydraulic shop. 120 micron (assured, but great for the end of an oil pickup as the crap sticks to the outside where it can be brushed off) +cleanable -coarse
Old t shirts (good, depending on weave about 2-20 micron I guess, unless it has holes in it!) put one in a drum with the arms and neck sewn up, fold waist over the lip, put a hole in the base to line up with the filler of the one you stack it on and cheapo filter. Pour oil in top, leave for oil to drain through. +cheap, good, set and leave to filter -unknown tolerance
Bag filters. Can be adapted with a plumbing fittings for forced pressure feeding. +cleanable -not easlily availible
Gravity. Slow but easy. +easy -need backlog of oil
Jeans. about 1/2 a micron, but slow going.
Oil filters. Beware the bypass valve though! found out the hard way on the gemini.
Bog roll. Punch heaps of holes in a drum, cover in flyscreen, lay out the toilet roll on top, about 4 layers thick. make sure no holes and pour slowly on top. mucky at best.

currently using
gravity as much as possible (4 -8 weeks)
t shirt
(pump to) 5 micron bag
(pump to car)
I try to keep the hydrogenated oils in the drum, where they then go for Dad to make bio from.

[Guest Close David]

Re: Oil settling

Hey Chris,

I tried the toilet paper idea but couldn't get it to work. I used a stainless steel strainer as the support and put in some clear oil that stayed there all day without any appreciable movement.

I also was using a synthetic Chamiox for doing the rough filtering but with setteled oil I found I was catching so few particles with it despite how fine a weave it was, I just went straight to filtering after settling.

I have been double settling in settling in a 200l drum and pumping off the top to a 60L drum and resettling that for a minimum of 2 weeks. Again I found that this didn't make much difference, the second settling only let the fats I picked up by sucking too deep off the main drum settle which wasn't much anyway.

I now pump the top oil from the 20L tins into the 60L drums and when I hit the fat, the remainder in those tins goes into the 200L drums. I manage to get about another 80L of clear oil out of the 200 once it has settled.

I now just test the depth of the fat before I start pumping into the drums for the blendable oil and raise the dip tube up above the fat level. Once I have got all the good oil, I do another dip test to find where the layer of grits is and again raise the dip tube up a few inches. I pump all the fat into tins to give to a bio maker and then suck the remaining rubbish out and use it for fuel in the wood fire oven.

Because I was able to get a good headstart with my oil by collecting it before I had a car using it, I am now fortunate in that I have plenty of time to settle all the oil I get which seems the best main filtration method of all.

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Oil settling

I tried the toilet paper idea but couldn't get it to work. I used a stainless steel strainer as the support and put in some clear oil that stayed there all day without any appreciable movement.

Perhaps David you are using a better quality toilet paper than me? Not the real thin stuff? I guess I used a 20L drum to hold it in (more backpressure?), but it seemed to go through fine. I still would not use it, it was mucky to reload the filter without contaminating the "clean" side.

Our filtering methods seem very similar (it must be "great minds think alike" not "fools never differ" ) the only few variations are after pouring off the top of the 20L drums it comes in (stopping when I hit the fat) I then pour the dregs into another 20L drum where it either settles again or goes to bio. I also let it sit in a 200L drum "clean" (still there is some settling out) before it goes into the car. Avoiding the fats seems the trick to filtering and not cleaning filters.

I found setting up the home end of the process as difficult as the car end.

Definately gravity is the most important to include.

[W123 x 2 Senior Member Find all posts View Profile Close W123 x 2]

Re: Oil settling

Hi David and Chris,
A couple of suggestions which work for me. This is my new simplified filtration/ dewatering system mark IV.
First I cold filter through a coarse mesh (fly wire) and nylon filter (panty hose) removes the dead rodents and hydrogenated 'lumpy bits'. This is then placed in an old oil heater tank, a flat wall mounted unit for settling.

Part A) The difference is that this tank is painted black and mounted on a north facing wall with no shading and wrapped in a second hand clear poly carbonate roofing. This raises the settling oil to 50 degrees or more and both the fine particulate and water settle out within a few days. I often leave it a fortnight "to be sure, to be sure". Flash tests confirm no water.

Part B) These oil tanks are readily available at tips etc. and have a tap at the bottom for draining sludge and water which I do at the end of settling; open tap, drain sludge into bucket, turn tap off when clear oil starts flowing. I have mounted second 25mm gate valve 100mm above the bottom of the tank and it is from this point that all my clean dewatered oil is drawn. Fine particulate filtering occurs after this, then blending then into the tank or storage.

Pretty simple process and it seems to get the oil (mostly used cotton seed) clean enough that the 5 micron filter is still clean after approx 400 litres. I believe that it is the heat (passive solar in this case), that greatly enhances the settling process. Certainly speeds up the process anyway as I have tested oil after two days and it is clean and no cleaner (particulate or water) after two weeks.
Obviously the type and quality of your WVO will affect these results, but it works for me.
Cheers, Michael

[Guest Close David]

Re: Oil settling

Hi Michael,

I was wondering about settling in the sun or shade but with your report I now know which way to go. I might even look at painting my drums black Certainly seems like your arrangement is very efficent heating the oil.

I test my oil every so often for water but so far haven't had any problem with it. I was reading some threads on the info pop site the other day and it seems the yanks have an obsession with it. Every second thread seems to have some over the top argument about wether it is allowable to have one part of water per million or per billion in the oil and what is the best way to get it so dry, it tries to suck the moisture from your body if you stand too close!

I tested mine on a very hot bit of metal the other night and noticed a lot of bubbles but no crackling. Concerned, I went inside and opened a new bottle of oil ( and suffered the wrath of her indoors for not using the already opened bottle) and found this oil given the same test possibly had more bubbles. I concluded my near red hot plate I had pulled from the fire was probably a little too enthuastic for the test but my oil was free of water anyway. I know the place I get it from turn off the fryers and let the oil cool a bit then drain it straight back into the drums it came out of. I have never found water in it yet.

I had also thought about a cone bottom drum for settling and tapping off the fat and crunchy's or using a standpipe arrangement like you describe. I am waiting to hear back on a new source of oil which I believe will be very clean to start with so I'm holding off doing anything with my filtering setup till I know what oil I am likely to be getting and set myself up something substantial and suitable from there.

[W123 x 2 Senior Member Find all posts View Profile Close W123 x 2]

Re: Oil settling

Yep, the yanks are scared stiff about water in WVO and I got a lot of ideas from infopop. Water is not the issue otherwise water injection would be a problem. It appears that water from WVO contains acids and dissolved salts that pit the injectors and pumps, causing at best bad spray patterns and at worst IP failure.

Incidentally, I test my oil a lot in summer on the BBQ plate .

Cone bottoms can be expensive but dead solar HWS have a dome bottom with central outlet. These are cheap ($20) as the panels fail before the tank, which is often stainless steel, and about 350 litres. Already insulated with polyurethane which means heating with a wand will work but solar requires stripping the insul off. Cut in half one would be a good size for a batch. I've got one but haven't fiddle with it yet.

Cheers Michael

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Oil settling

Michael how do you do your water test? Do you look for spitting or small bubbles forming? Water if disolved in oil will not be a big issue I would imagine (small bubbles), but of course if it can seperate out (spitting) it will be a bigger issue.
Also I belive a 2 tank system to be "nicer" on injection pumps, as whatever is in the oil will be flushed from the IP on shutdown, unlike a 1 tank or biodiesel setup, where it sits in the IP 24/7

[W123 x 2 Senior Member Find all posts View Profile Close W123 x 2]

Re: Oil settling

Hi Chris, I use half an old jaffle iron over the open grill section of the BBQ, I let it get hot on the low setting and drop in a table spoon of oil. It spits (big steam bubbles) if there is water in it and some times v. small steam bubbles form and just sit there. I now use an old welding mask with clear lens to get close up and inspect, don't ask why but boiling oil ain't fun. Anyway I don't think heat is the panacea but it certainly gets rid of water in my oil, and hopefully the acids and salts too.

I like the modest heat (50 - 60 degrees C) selttling solution because the water drops out of suspension carrying with it the acids/salts. I've read of people raising the temps to water boiling range in their WVO. Seems silly to me as the water will be removed leaving the salts and possibly acids behind in the oil.

Yep a two tank system would solve many of the problems with the IP but I read on infopop that the acids and salts still eat away at the nozzles and stuff the spray pattern up, causing incomplete combustion etc.

[Alga Senior Member Find all posts View Profile Close Alga]

Re: Oil settling

"I grabbed a new filter and a drum of oil straight from the chip shop and pumped it through with my little pump."

David could you tell me what your little pump is and where you got it, I'm having great trouble filtering as I keep getting the slimmy fatty stuff in my pre-filter (t-Shirt).