Sciencemadness Discussion Board

Thinning solid fat/oils for injecting (venturi air suction) into forge?

RogueRose - 23-7-2018 at 20:16

SO I have 25-30 gallons of clean but rancid hard fats (lard, tallow, hydrogenated veggie oils and palm kernel oil) as well as about 20-25 gallons of old canola & soy oil (used but filtered though 2 micron filter). I need to get somethign that will flow via suction from a 45-90PSI air stream (venturi pump / aspirator type pump). Heating is a real PITA and not a great option b/c when too hot too much oil is sucked up with the air and it is very difficult to monitor the flow rate. So I need to figure out how get it a reasonable consistency from 60-90F which will be the room temp where used.

mixing the hard fats with the veggie oils makes a lumpy pudding mix and just doesn't work well. So I thought about adding a fuel/hydrocarbon, and blending it with the heated hard fats and maybe with the veggie oils.

I have diesel, biod, gasoline, E85, kerosene and methanol - I can probably also get #2 heating oil (possibly for free). The diesel is probably the best cost/BTU wise & Biodiesel is same price but I think it has 10,000 BTU less per gallon (not huge deal though). Gasoline is probably the thinnest and economical as well, E85 is about 15% more per gallon than gasoline (regular 87 or 89 octane) then methanol (least BTU) at $4.24/gallon (would take 2 hours to get it though).

So I thought about mixing one of the fuels with the hard fats until liquid. Heat the fats till melted (about 100-120F in hot water bath) then add fuel, blend, allow to settle. IDK if it will stay mixed or if it will seperate. Will one fuel keep it mixed?

Another idea was adding all oils/fats, heating, then adding fuels as the veggie oils might drop the freezing point of the hard facts, so less need for fuels over all.

This will be sprayed into a forge of at least 1200F before the fuel is sprayed in so it should be plenty hot to ignite. I'm just wondering if one fuel will help give more compete combustion of the oils/fats? Mayube even a mix of diesel, gasoline and methanol,

The consistency isn't super crytical, it will probaly get up to 100F by being in proximity to the forge so with added fuel, it is going to be liquid at this point, I'm just wondering if one of these fuels might help everything burn better, even though it will be sprayed in a very fine mist.

Any suggestions on what could be a good mix here?

OldNubbins - 23-7-2018 at 21:10

Try rendering the thicker fats and oils containing solids several times. Heat up low and slow for several hours (don't burn), strain off the solids, repeat several times. You would be surprised how much solidified proteins and other such nastiness continue to coagulate and drop out after multiple renderings. Eventually you will be blessed with a clear oil that smells much cleaner and doesn't solidify as easy at lower temperatures. You can then convert it straight to bio-diesel or thin it with something like kerosene (which I have done in the past for the same application)

Sulaiman - 23-7-2018 at 22:02

Just today I was cleaning glassware of partially polymerised vegetable oil,
kerosene (paraffin) works,
I have gasoline (petrol) but I thoght it a little too volatile - fire risk
I have vegetable and mineral oils but I thought they would be too viscous.
Almost all of the oil/fat dissolved in the kerosene.
A few remaining solid fatty remains were removed/cleaned with NaOH solution and swirling glass beads.
I mention it mainly due to coincidence, not because I have expertise in this topic.

RogueRose - 23-7-2018 at 22:47

Quote: Originally posted by OldNubbins  
Try rendering the thicker fats and oils containing solids several times. Heat up low and slow for several hours (don't burn), strain off the solids, repeat several times. You would be surprised how much solidified proteins and other such nastiness continue to coagulate and drop out after multiple renderings. Eventually you will be blessed with a clear oil that smells much cleaner and doesn't solidify as easy at lower temperatures. You can then convert it straight to bio-diesel or thin it with something like kerosene (which I have done in the past for the same application)


The lard and tallow is completely rendered and it was filtered through a very fine filter when it was good clean fat. the problem is that it sat in a very hot attic over 2 summers so it went bad with a little off-coloring, yellow, orange, pink, but I haven't seen anything solid in it when I melted it.

The problem is that it just congels to hard oils.

I'll try adding some kerosene to it when it's liquid and see how little I can get away with. I see no need in trying to convert to biodiesel if it is just going to be burnt in a forge.

I've never really used oils or fats for this before. I've soaked wood chippings and saw dust, making cakes or gallon jug size "plugs" of fat/oil/sawdust/chips and then burned that but it was kind of messy and didn't burn real evenly, so that is why I thought going to a forced air/venturi might be the best solution. I know people use straight oil for this in their WVO stoves but they also often preheat the oils.

I wonder if preheating the air would be a good idea. Run the compressor line to a 1/4" SS tube coiled inside (or outside touching the steel drum/forge) the forge for a few turns, then exit the forge where the venturi pump can be attached and blow the very hot air/oil mix into the forge. If I have 45-90PSI at standard temp, I would think I would have a much higher PSI after it is heated to near 1200F or so, and it could really help with ignition as it would probably ignite as soon as the oil hits the hot air stream.

The venturi and nozzel is SS as well so I don't think it shoud have a problem dealing with the heat, though IDK about prolonged periods.

I've always been fascinated with the different methods of fueling a stove or forge with oil, fuel and waste oils and have seen a lot of different combos online, some are awesome (ingenious), some are fire traps.

Have you ever used old motor oil as a fuel? That seems like a good source of fuel as I think it has a VERY high BTU of 170,000 -190,000 from some sources I've seen. Can't really beat that!

unionised - 24-7-2018 at 01:48

Have you considered converting it to "bio diesel"?
You say you have methanol and you can almost certainly get NaOH.
The methyl esters will have significantly lower melting points that the original fats.

stygian - 24-7-2018 at 09:47

Converting to biodiesel would be an excellent way to go, and if the flow rate is too rapid you might be able to put a needle valve or similar into the feed line. As an oxygenate biodiesel may help improve combustion as well.

gnitseretni - 24-7-2018 at 14:38

Quote: Originally posted by RogueRose  
[
Have you ever used old motor oil as a fuel? That seems like a good source of fuel as I think it has a VERY high BTU of 170,000 -190,000 from some sources I've seen. Can't really beat that!


I used waste motor oil for my furnace back in the day when I was still melting metals. When I first constructed the furnace I didn't preheat the oil. But I added preheating later because during cold days the flow would slow down enough that it would take too long to melt the metal. Well too long for me anyway. Preheating the oil really saved a lot of time during cold days.

RogueRose - 24-7-2018 at 16:07

If I were going to use it in a vehicle, then I would consider Biodiesel conversion, but since it is simply for running a forge for melting metals and maybe to purify some compounds like K2CO3 from wood ash leaching, I think it is too much work.

I've never mixed diesel or kerosene with oil, IDK if they mix, nore do I know if they would mix with methanol. maybe a mix of the 3 would keep them from seperating, IDK, but I'm almost certain that it will lower the MP to a point where it will work for what I need as long as I don't get stratification of layers. I'll have to do a couple tests and see what happens with diesel & soy, diesel & fats, ethanol & soy & methanol & fats, then mix them together and see.

Thanks for the suggestions, this isn't something that I would think many people do as having this much hard fat isn't a common thing.

Also, if I needed glycerine for some reason, that might be a good reason to make biodiesel, but alas, I have no need ATM.

RogueRose - 24-7-2018 at 18:16

SO i have a current test running (chilling in the fridge).

I added 8ml of pure lard to 4 vials - heated to about 130F.

I then added 3ml, 1.5ml and 1ml of diesel into each of the vials, and then 3ml of methanol in another. The vial which received 1ml of diesel also got 2ml of soy oil which should help lower the MP of the lard.

Well the methanol didn't work with the lard, at all. It wouldn't mix with diesel either, so there is no way that a diesel/methanol mix would help any better than diesel alone.

vial A - 8ml Lard - 3ml diesel
vial B - 8ml Lard - 1.5ml diesel
vial C - 8ml Lard - 1ml diesel + 2ml soy oil (non-hydrogenated)


So after the 3 vials were in the fridge for about 3 hours @ 34 deg F, everything had thickened significantly and turned cloudy/opaque. The lard was pure white when I started then yellow when melted (same as diesel). After sitting out for 3-4 mins I swirled all vials and vial A was wobbly and soft, it had the most movement, but when swirled/agitated, it always returned to the same shape, kind of like jello, but much softer. Then vial C was almost the same but a little more stiff than A. Finally vial B had the least "jiggle" when aggitated by a decent amount in comparison. I do think that all of these could be pulled up with adequate suction, actually relatively low compared to trying to pull up solid pure lard. The color was the same in all vials.

I placed the vials in a water bath at 62F. A and C had almost identical characteristics, when swirled they would quickly coat the sides of the vial and then immediately pull back into the body of the solution, leaving almost no coating on the walls. Vial B was slightly thicker and when swirled the coating on the wall remained like a coating of thick syrup where as the other two acted like a moderately warm oil (say 120-140F- maybe even hotter - so I mean thinner) that only left a very thin film on the walls.

I am going to heat to about 80-90F and see if there is much difference, but from where I stand, I think A or C would work find for my application and I will guess that B would work as well (but requires more Diesel which is more cost).


I may try again with different ratios of soy/lard alone and see where the congeal point is in relation to the two. It is certain that the diesel drops the MP by a very high amount even at a 8:3 ratio - lard:diesel.

This is actually quite interesting because many WVO vehicles say they mix 50/50 with veggie oil and even up to 80:20 diesel/WVO "blends" (which may have any plant or animal fat) and it's been reported to be used in places like SoCal where temps aren't going to be an issue like up north.

I am curious to try gasoline with some of these and see how it compares to diesel. I have a feeling that IPA may work differently than methanol, and I'm interested in the behaviors of alcohols in the various fats/oils.

RogueRose - 24-7-2018 at 18:34

So at 80-85 the viscosities increased a lot. A was best by far, followed closely by C and even B wasn't far off. So it looks like this will work very nicely at any temp above about 60F which is great and I think I'm going to go with a mix of the following:

8 part hard fat, 1 part diesel and 3 parts veggie oil, which should give results closer to vial A with 1/3 of the Diesel used. Since I have enough veggie oil to even do 50/50 oil/fat, this won't be a problem, but I like having the oil for other things like baths, cutting, etc.

I'm just wondering if there is going to be a benefit when it comes to ignition by having more diesel in the mixture.

Has anyone used straight up diesel in a forge? I would think it would work, but I also think that a fat/oil might work better, though that is only from what I have read. They all have similar BTU's but their diesel's flash point is much lower than veggie oil or fats.

RogueRose - 25-7-2018 at 14:10

Found something very interesting. Last night the lard/diesel or lard/diesel/soy mix looked like winners. The methanol lard would not mix at all - oil water so I heated for 8 seconds in microwave, stirred and allowed to sit overnight. Now it is milky cloudy and it is the thinnest of all of them, and the best lard/diesel has nearly seperated now. It is like the two reversed, and I have the vials labeled so I didn't mix them up.

This seems worth investigating a little more

gnitseretni - 25-7-2018 at 16:42

Quote: Originally posted by RogueRose  

I've never mixed diesel or kerosene with oil, IDK if they mix.


They do mix. That's what I did before I was preheating the WMO. The diesel thins it down nicely.