Charcoal vs. Wood gasification

Lets talk about the pros and cons of both types of gasification here so new comers will know the differences of what to expect.
This will include all types of applications.
Bob

7 Likes

The charcoal gasifer has its limits for how far you can go. But if you can carry enough charcoal for a round trip it is great. Charcoal Gasifer total unit weight vs. Wood Gasifier total unit weight is a big difference in weight. Charcoal weights less but is more bulky per weight of wood and energy stored. Charcoal has half the energy in charcoal vs. Wood, but you can get some back in water being added and making Hydrogen to burn on.
Some have said losses are minium. Also making charcoal first is more time consuming then processing wood. Maintenance is less with charcoal.
Lots of factors to think about.
Bob

5 Likes

I can definitely name some for charcoal, I can’t speak for raw wood yet other than perceived observations from others.

Pros for Charcoal:
For Charcoal you will typically have a system that weighs less than wood gasifiers

with an updraft charcoal gasifier you can run smaller engines easier

With some methods of making the charcoal you don’t need to cut down the wood into chunks(flame cap method)

Updrafts don’t need a lot of cooling down the gas, usually cool enough once it’s filtered until it runs low on fuel

Charcoal doesn’t weigh a lot so it’s easier to carry the fuel

Filtration is pretty easy, a sewn up towel will do the trick

Byproduct of charcoal production is the dust, great to add into compost

Edit: Charcoal is more fuel efficient because it doesn’t spend heat energy to drive moisture out

Cons for Charcoal:
Nozzle design can be crucial and without good materials or a big mass to absorb heat the nozzles will just melt away/degrade rapidly

If you run an updraft and use unfinished charcoal you run the risk of tarring up your engine

Updrafts like a specific charcoal size to keep heat down and gas rich enough(I learned this the hard way)

You have to make the charcoal which means you can’t let yourself annoy your neighbors with smoke and steam and dust

You have to grind, classify, then dry store the charcoal

Sort of a double edged sword, the light weight of the charcoal means your hopper doesn’t go as far as a raw wood system if we go off of the average 2 miles per pound

Ash melts into slag, I personally find slag annoying to clean out.

9 Likes

Cody, you sumerised it well. Just one thing, i find mileage per same volume hopper is better with charcoal. How do you guys feel about this?

Not to mention weight, charcoal is way more energy dense per weigt.

10 Likes

With my 55 gallon drum I would get about 100 miles per refill of 30 gallons if I was careful about driving, not sure how far others get on a hopper of 30 gallons.

5 Likes

When H2O is added into the charcoal I agree, plus no dust. Nice to work with.
Bob

5 Likes

I have a lot of experience running the Predator 8750 on both fuels. In my experience the little M-2 I just tested has 1/3 less volume fuel capacity as the older M-2 units in raw fuel form. The run time is actually slightly longer on the charcoal unit with less capacity. Even though there is less energy density by volume the charcoal gasification process is much more efficient then wood gasification. Charcoal by weight is much more energy dense, as most wood is going to have a moisture content. Charcoal is 9600 BTU per lb a quick google search tells me that 15% MC wood is around 6800 btu. You can not just compare fuel energy density pr weight or volume you must factor the efficiencies the the gasifier reactions as well amongst many other factors. All analysis Ive seen so far are incomplete.

As for raw fuel Versus Charcoal the energy you put into fuel production verses what you get out of the application is about the same at the smaller scale. When you add in fuel energy to run a chipper, add in the losses from that process, add in the 30% from, the gasification process and then the loss in char ash (if not reclaimed) it actually equals out. Now larger scale with a chunker thats a different story.

However if you are using your charcoaling system for heat or are reclaiming the gas produced it is hands down far more efficient. Then factor this in, if can use that gas for appliances and use it as a direct energy conversion instead of an electric counterpart this is a HUGE efficiency gain. As this gas is for one reclaimed from process and two if you use the electric counter part you lose over 75% in engine losses converting this gas into electric energy.

Charcoal is only less efficient if you allow it to be. Charcoal fuel production can give you energy back, not so easy with raw wood processing.

Pro’s to charcoal:

No tar (number one)
Self sustaining and stable under operation
Fast Starting
Water Injection reclaim
Simpler design
Less Complexity
Less cost to build
Lower Maintenance and servicing (No tar in your filter to deal with)
No condensate
Little to no ash clean out servicing
No waiting for fuel to dry
Faster fuel process time
Wider range of Fuel feed stock. ( You can only feed a chipper stock that fits. You are really unlimited to what you can feed a kiln or retort) << That is also wasted fuel if you cant use it
Higher energy dense fuel (smaller goes farther)
Can reclaim Fuel process for heat and other uses
Higher gas energy density with water injection
All around cleaner gas

OK now, Pros to Wood Gasification:

Better for a truck? I give up you got me.:slight_smile:

8 Likes

Matt, if someone could run a big engine on charcoal it would be all over for wood gasifers ruling as king of the V-8 driving on wood. Lets say 50 miles on a hopper same size as wood gas hopper But that has not been done yet that I know of. Smaller engines yes. Anyone willing to try It on a big V-8?
Bob

6 Likes

Yeah thats what Im developing the M-4 Alpha to do. A team of them should be able to do it.

If my Peru order comes in that Is what I plan to bring to Argos is the M-4 Alpha teamed system in truck carry mode. But Ill more than likely have the S-10 with the 2.5 ltr.

7 Likes

I may try it for the 4.3L, that’s a lot of displacement.
Eddy Ramos’ Ford Falcon has the Inline 6 3.6L and he hasn’t had issues. I’m amazed a 19mm nozzle works so well even if it is an updraft.

7 Likes

My only question is how do you determine when the hopper is almost empty on a downdraft charcoal unit? Hopper temp same as raw wood? I knew that for updrafts you measure exit gas temps and it climbs as it has less charcoal to scrub with but with a downdraft it should be near constant temps.

7 Likes

Yes Cody, my down draft charcoal gasifer when running low on fuel heats the hopper up. So watching the hopper temperature lets you know.
Bob

7 Likes

Cody, its actualy easyer as there is a sharp spike in temperature once charcoal gets low, compared to wood that takes some time for the temp to rise. On the other hand, when there is a heat spike on a charcoal gasifier, that realy is it and you need stoping NOW, while with wood you got a mile or two

9 Likes

Yes what Kristijan said. This why on my unit it will have a quick fill feature that I can operate from the drivers seat to give time to find a good spot to pull over and do a complete refill on the hopper or it might just start to feed more charcoal in from a storage hopper and I can just keep driving. Lots of possibilities to work with.
Bob

5 Likes

Only to mention, since im somewhat stuck in the history aspects, after ww2 there was a investigetion on how to prepare if there come more fuel shortages in future, one of their goal was to investigate if charcoal gassing should be “not allowed” in a future fuel shortage, (due to fuel economy, more wood for same power, labour for making charcoal,) what they came up with was that there shoul be used both wood AND charcoal, charcoal was better and easier for smaller applications, and easier to use for “novices” if i remember correctly there was some limit, about up to 1,8 liters of displacement for charcoal, ofcourse this investigation was based on a very large scale, supplying a whole country with fuel.
Little note: i have somewhere dimensions for Svedlunds charcoal gasifier, rated for 7 liters engine displacement. :slightly_smiling_face:

10 Likes

Very interesting Bob, is this something you built, or plan to build? I like the idea, auger feed?

5 Likes

Goran, whenever you can find documents on any of the charcoal gasifier please upload them. Chris could add them to the Library section. Do you have any of the Mako designs?

3 Likes

Charcoal vs wood gasification is a short question . My answer would be to do what ?

The above is kinda like asking what gun is the best for hunting ? :grinning:

18 Likes

I have three ideas for this on the fly build for loading a low hopper. It is a side of the hopper dump it in and a side of the hopper push it in for wood gasification. The charcoal is a auger feed. All on paper for now. Much cheaper to change design flaws this way.
Bob

4 Likes

Yes you are right on the question Wayne. And I know it is a very open one. But I just learned somethings new I did not know and that is great from Goran, and Matt.
What gun for hunting? The one that shoots straight and hits the target.
Bob

5 Likes