[Gasification] Screening Char

[andrew schofield]

Dear Doug,

  At Abu grab in Iraq, Bruce Jackson had good sucess gasifying charred shipping pallet-wood. I've since become friends with Bruce and have visited his camp in Michigan. He operates gasified four-cylinder tractors for powering saws in the bush.

 Our Friend Greg Manning says most understandably that slipped-char is the "conveyor-belt for ash". This makes sense to me. A hearth can plug up quickly with fines, if not removed continuously.

 When driving moderate distances on wood blocks last year, I became flooded with quantities of excess char removed from my imbert ash-pit. I bagged up the char, and gave it to friends involved with cutting and removing a prolific tree-species that had begun to displace native beech/maple stands. They burned the char to ash in a special pizza oven during their autumn music-fest just for fun. They had been using raw wood in the oven, but it smoked objectionably during the party the year before. They loved the char product.

 Visiting Jim Mason's shop this spring, and talking with biochar experimenters there, I learned the char from my imbert may not be most useful for gardening, because my char is made at temperatures way higher than temperatures at which the most beneficial biochar is made.

 Excess quantities of char required for cooking pizzas at parties will be expected when heavier imbert gasification use of this invasive-species biomass is at the higher potential.
The trees sprout anew from cut stumps faster than the boys in the woods can saw, and skid.

 What size char is good for the charcoal cross-draft you described? No dust I assume...
The engine displacement-fit here is about 5 Liter, give or take 1/2 L.

Andrew Schofield
Captain; Little Schooner Madeline

 

> Hi Jai,
> You ask:
> 
> Can any one can tell me about the gasification of horizontal gasification process how the grid can be made and position of the nozzles should be. 
> 
> The only horizontal gasification that may fit your question, is applied to charcoal gasifiers, and also in a modified version to those used for coal, and then of the better quality like anthracite. In technical terms, you would refer to these as cross draft, which in a bed of charcoal needs no tar burning or cracking to make clean gas. These are not suitable for raw fuels.
> 
> In rough dimensions, you have a single water cooled nozzle/steam generator that should be able to slide in and out to set the best oxidation lobe position, so that the distance between the grate and nozzle can vary from say, 20-25cm (8-10").
> The nozzle bore can be 2-3cm, or smaller depending on the output you seek. I am sure you will find very specific information in any books discussing charcoal gasifiers. The water is fed to the nozzle by drip control, and the steam generated is added to the in going air, to make up the hydrogen content of the gas.
> 
> The grate should have vertical bars about 1cm apart and say 10x10cm for a smaller output, and about 15x15cm if you use a larger nozzle.
> 
> Because ash will form along the underside of the oxidation lobe, you will need to be able to drop the char bed by shaking a second support grate located about 5cm under the air nozzle. Failure to do this will see the ash melt and clinker form.
> 
> I suggest you read up on charcoal gasification before you build anything, but it is hard to fail when the fuel is just charcoal.
> You can see an old one from WW2 on the Fluidyne Archive  www.fluidynenz.250x.com  under Australian WW2 gasifier. These were photos, not digital, so not sure if I can find any shots of the insides, but will try and find them if this is what you have in mind for you project.
> 
> Hope this helps.
> Doug Williams,
> Fluidyne.


 		 	   		  
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