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Burnt Rice Hulls


Somtham

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These char ovens/gasifiers. Can they be set up to burn the gas that they are producing? Do they produce enough to become self sustaining?

That is the whole idea. The thermal efficiency can vary quite markedly depending on design and use.

more information please, never heard of these ovens

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These char ovens/gasifiers. Can they be set up to burn the gas that they are producing? Do they produce enough to become self sustaining?

That is the whole idea. The thermal efficiency can vary quite markedly depending on design and use.

more information please, never heard of these ovens

Basically a sealed drum with a single vent pipe. You fill it full of biomass i.e. wood and light a fire under it. "cooking" the mass in the absence of oxygen produces a, charcoal and b, a flammable gas that can be used for various purposes. In ww2 cars were converted to run such systems due to petrol shortages. Google gasifier.

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These char ovens/gasifiers. Can they be set up to burn the gas that they are producing? Do they produce enough to become self sustaining?

Yes, almost. The closest I have seen was a drum on its side with a metal plate welded across near the bottom creating two chambers. The top chamber is crammed full of wood and has a chimney that comes out the top and then down where it enters the bottom chamber it narrows and becomes a burner. You light a small fire in the bottom chamber and then close the drum up. As the gas is given off the wood in the top it passes into the bottom where it ignites and so the process go on until all the gas is used up. The pictures I saw had a collection point in the chimney were the wood alchol was drawn off.

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These char ovens/gasifiers. Can they be set up to burn the gas that they are producing? Do they produce enough to become self sustaining?

Yes, almost. The closest I have seen was a drum on its side with a metal plate welded across near the bottom creating two chambers. The top chamber is crammed full of wood and has a chimney that comes out the top and then down where it enters the bottom chamber it narrows and becomes a burner. You light a small fire in the bottom chamber and then close the drum up. As the gas is given off the wood in the top it passes into the bottom where it ignites and so the process go on until all the gas is used up. The pictures I saw had a collection point in the chimney were the wood alchol was drawn off.

44 gallon drum, some pipe and a plate.

That sounds cheap and cheerful and worth a go.

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It was some time ago when I looked at this pyrolisis burning technology looking for a better way to produce biochar from rice hulls, do not have wood. You can find the pictures and even building details on the web, I did, if not let me know and this magpie will hunt around. Just maybe I kept a copy.

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  • 1 month later...

From what I've read and my own rough testing, rice husk biochar has a ph of 8-9, making it excellent for acidic soils, particularly sandy soils.

Before I realized how alkaline it was, i added quiet a lot to putting mixes, along with compost, aged manure and rice husk. I think thevph is probably to high. Does anyone know if the alkalinity will drop over time?

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From what I've read and my own rough testing, rice husk biochar has a ph of 8-9, making it excellent for acidic soils, particularly sandy soils.

Before I realized how alkaline it was, i added quiet a lot to putting mixes, along with compost, aged manure and rice husk. I think thevph is probably to high. Does anyone know if the alkalinity will drop over time?

From what I understand, CRH pH persists for a much period than does straw or rice hulls. I use probiotic in the compost which is heavily populated with lactic acid bacteria and that should provide some balance, but I have not tested it. The CRH definitely traps much of the potential nitrogen in the composting process.

Adding CRH to a soil blend with no composting, not so sure.

What it will achieve is an alternative to adding lime that lasts longer. Sequestering carbon and adding silica. A source of Calcium is still missing however.

Edited by IsaanAussie
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  • 10 months later...

The main benefit that biochar imparts on the soil is as a refuge for water, nutrients, microbes, indigenous micro flora etc. A spoonful of char has a surface area of c. an acre. It's like a micro sponge, full of millions of tiny tunnels that gets inhabited. A place of refuge during floods and drought alike and always available to plant roots.The deeper you can get it the longer the drought it can outlast. It takes 2 years to charge up fully in nature, so mixing it with compost and EM first (a la IanAussie) is a must, as it will compete for moisture and nutrients in it's raw state. It does not degrade, even after thousands of years. (Amazon- Terra Preta)

This is something that the depleted corn/sugar soils of Issan need.

Regards.

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We have several topics covering CRH and other forms of biochar. We have talked about the polluting emissions charring rice hulls. Of course if we can burn the emitted gases completely then all is well.

I think I may have found the way......

post-56811-0-83612600-1365084700_thumb.j

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The Philippine IRRI is a great source of information on most things to do with rice. The Philippines are leaders in the development of pyrolisis burners and stoves. I have a contact that I can secure the details of construction for a CRH furnace with a gas output for a one time licence fee of USD2,000. If anyone is interested in a collective project to build these things please contact me by PM.

Basically if you have access to rice hulls this will allow you to dry rice, pellets, fish, whatever, at about 6 tonnes per shot. Of course the CRH is the primary output. The only energy input is enough electricity to drive a few fans.

Equally if you wished to scrub the gas and use it to power a gas engine that can be done as well.

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