Sciencemadness Discussion Board

Deep fried wood served with side of sautee'd saw-dust - higher energy wood products

RogueRose - 8-1-2016 at 23:19

My metal forge eats up wood and charcoal, especially with the blower on high. I use dry high density woods (oak usually) but I hate filling it too often. I also have access to waste vege oil. I thought to myself - "self - your WO burner is coming along nicely but sometimes wood works better for some things AND you have the WVO available. What are your options here?"

So I filled a pot up with WVO and put in cut/split pieces of wood, put a weight on top to submerge and put it on the burner. At 212 deg, bubbles stated forming on the surface. It was foaming up with H2O coming out of the ends of the wood. I let the temp get to 350 and cooked until no more water was coming out (no foaming) and then cooked another hour or so. Total time was about 3 hours on med heat on the range. Sure this uses energy but I needed to heat the house so I figured the heat from that will help and not be an extra cost (is that correct thinking or am I missing something here?)

When removed from heat I allowed the everything to cool in the oil then put in a strainer and let sit for a few hours (I thought the cooling might suck in some oil) and then weighed.

Weight of the wood was 975g before frying and 1035 afterwards so 60g of additional weight. I'm guessing the wood was 12-18% water so that means 117-176g of water evaporated and was replaced with oil - let's say 147g of water (147 + 60 = 207g of oil) and 828g (1.823 lbs) of wood.

White oak with 2-4% moisture is about 7,921 BTU/lb
-14,440 BTU in this 828g of ~3% moisture oak

Vege oil is about 128,000 BTU / gal or 35.9 BTU/g
-7,432 BTU in the 207g

Total BTU 1035g of wood/oil & tiny bit H2O
-21,872 BTU total in sample
-21,132 BTU/kg
-9,594 BTU/lb

6,138 BTU/lb in above avg dryness wood (White Oak) before frying
56.3% increase in energy content - or -
Untreated wood has 64% the energy of the treated wood.

BTU / lb of fuels
20,583 - gasoline
22,278 - diesel # 2

So the treated wood is about 47% heating value of gasoline and 43% of diesel - vs - 29% of gasoline and 27.6% of diesel for unprocessed (very dry) wood.

Well I pout about 100g of wood into a hot forge (on top of red coals) and within 10-15 seconds it was ablaze and burning very nicely with natural "breathing". Turning the blower on (very weak fan - probably < than 50 CFM) it turned into an amazing blaze that was very bright yellow to white flames. It was very impressive. I would say that it burnt at the same speed as untreated pieces of the same size but with MUCH more heat.

As far as smoke or pollution, it did burn cleaner with the blower and it had a slight bit of black smoke without the blower. I have no pics of this but I may take some next time and possibly video.

Does anyone have any suggestions on how to improve on this or some insights on this process? I would REALLY like to be able to do this whole process with a pressure cooker at 1 ATM (~15 bar) as I think it would make the wood absorb MUCH more oil. I don't know how pressure cookers work/react when cooking with oil instead of water (input greatly appreciated!!).

Well, I think that's about it on this topic. I'm going to try something similar with sawdust with a pressed product so I can get a uniform size/energy content so I know burn rate and heat for doing specific applications.

Little_Ghost_again - 9-1-2016 at 17:16

I like this alot, thanks for sharing the info. I am looking at making pellet fuels for a biomass boiler and wondered myself about adding an oxidizer, it didnt occur to me to use oil. In my case I have access to waste oils and lard, I wonder how waste engine oil treated wood burns (from pollution perspective) given that a bio boiler often has forced air?

Just as an aside, I centrifuge waste engine oil first, it seems to remove alot of gunk and water

[Edited on 10-1-2016 by Little_Ghost_again]

RogueRose - 9-1-2016 at 21:30

Quote: Originally posted by Little_Ghost_again  
I like this alot, thanks for sharing the info. I am looking at making pellet fuels for a biomass boiler and wondered myself about adding an oxidizer, it didnt occur to me to use oil. In my case I have access to waste oils and lard, I wonder how waste engine oil treated wood burns (from pollution perspective) given that a bio boiler often has forced air?

Just as an aside, I centrifuge waste engine oil first, it seems to remove alot of gunk and water

[Edited on 10-1-2016 by Little_Ghost_again]


I have had VERY good success using VERY tightly packed cotton swabs in PVC pipe or a wide mouth plastic jug (jug is gravity fed & slow). Use square swabs and line a row up with them over-lapping by about 80% and then roll them very tightly and press into bottle mouth. for a 2L bottle I use about 16-22 swabs and it is a PITA to get them in, but the product looks pure (this is for water based solutions). Do the same for PVC but use some kind of pressure or vacuum to aid filtering as well has heat for oil.

As far as motor oil, there should only be fuel and carbonized oil in the oil (maybe some dissolved gases like NOx, SO3, etc but minimal I would think). Filtering should remove the carbon. Either way, when burning, it will all burn and with forced air and a proper combustion setup (maybe a re-burner after primary combustion chamber where additional air is blown in - this can REALLY help emmissions - think of it like a catalytic converter).

I'm going to look into what goes into pressure cooking with oil and how dangerous it is. I suspect I can get the weight of the wood to at least double (minus water loss) would be about a 300-350% increase of fuel content.

these setups are ideal if liquid fuels can't be used or if it is too much of a bother to change from solid to liquid. If a WO burner can be used I don't know if there is a benefit to impregnating the wood over burning the WO straight. Obviously if the stove can't handle WO then impregnation is best.

Another benefit is ability to control heat output. if little heat is requires, place small pieces in or a single large piece with less surface area than same volume of many little pieces, this will give less heat but long burn time.

there's lots of reasons to try this. I wouldn't recommend this unless you have a good blower system as it wil produce soot if not enough air is added (of course less fuel could be added).

Also, have some sand/kitty litter/clay near by in case of fire. This stuff can be pretty nasty. I was amazed that there were no cracks and pops from the cooked wood. I think that is b/c there was no water so there were no sparks flying like usual - bit plus in my book.

[Edited on 10-1-2016 by RogueRose]

hyfalcon - 10-1-2016 at 00:51

Sounds like you're trying to make coal out of wood. Why not just find some coal? Is it an access issue? If coal doesn't get hot enough quick enough, coke it first. You'll go through some fuel quick but it will get very hot in doing so.

RogueRose - 10-1-2016 at 03:07

Quote: Originally posted by hyfalcon  
Sounds like you're trying to make coal out of wood. Why not just find some coal? Is it an access issue? If coal doesn't get hot enough quick enough, coke it first. You'll go through some fuel quick but it will get very hot in doing so.


Coal doesn't work well for my application. I've had some very strange situations were the coal is burning orange/white hot and I come back 10 mins later and it's all but cold. All I had done was turn down the blower from high to med which is still a good amount of air. The coal wasn't burnt up yet and was able to be burnt in the next batch. I'm sure I could use it if I rebuilt the combustion chamber.

I was trying to find another way to use waste oil instead of using a pressurized blower. There are some nice things about being able to use solid fuels at times, especially if it has a high energy density (hence popularity of coal).

violet sin - 10-1-2016 at 11:51

I had typed this twice yesterday, but couldn't find a vid of it... But if you wanted to maximize oil absorbtion, you could make a vac chamber, load with wood and oil, apply a vacuum and sink the oil in while removing bubbles/moisture from wood.

The video I was trying to find was someone removing bubbles from a HV transformer's windings in an oil tank. Instead a bunch of transformer oil purification machine videos popped up :(

I know a household vacuum cleaner will collapse a standard plastic 5 gal bucket... Tried making a big buchner funnel with a 5gal bucket, vacuum and a hand drill for the lid. ~1/3 of the top surface area was holes, and damp cloth payed over, it crunched in the bucket sides like a soda can. Good idea for makeshift vac assisted filter, but not in practice.

Just a thought.

Broken Gears - 11-1-2016 at 02:41

Maybe a bit off-topic, but can't you use a homemade propane burner or just a waste oil burner instead? Maybe more expensive, but more reliable. I don't have any problems with my DIY propane furnace.
Have a look at backyardmetalcasting.com for ideas.