Biochar gasifier questions

I am in the process of building a biochar gasifier like the one shown here http://biocharproject.org/biochar-technology/tlud-gassifier-awesome-modifications-karl-frogner-phd/

As a fuel I have bamboo offcuts, some are long peices that will need to be cut down, while others are peices of 1.5" - 2.5" and 6" long 12", these are from the base of the pole and are almost solid. Most of the bamboo is dry, some is still a bit green however.

I also have access to tons of rice husks. These are very fine particles, smaller than wood chips, but nothing like sawdust. They are very uniform.

Does anyone know if these fuels can work and what are the best steps to ensure success? I chose this gasifier because I already have the 55 gallon drum and because it has lots of adjustments for air flow, so I figured it may be suited to a wide variety of fuels.

Any help is much appreciated.

There are designs for rice hull cook stoves, http://www.sulit.com.ph/index.php/classifieds+directory/q/rice+husk+stove+design . What is your gasifier to be used for?

It would primarily be used for bamboo, however as I need biochar and have rice husks, I would also like to use these.

Sorry, my question was not clear. I meant what are you using the gasifier for? Is it for cooking or for heat or to produce charcoal?

I'll be using it to make biochar/charcoal

Today I tried the oven with a rice husks, it didn't really ignite, there was lots of smoke so after more than an hour I put it out with water. The rice husks seem to have burn't whether I end up with biochar or ash I'm not sure, the drum was hot over it''s whole length.

I think the rice husk may to fine, not allowing enough air, bamboo or wood may be a better choice. From what I've read starting the TLUD's takes practice, so any pointers would be much appreciated.

Google "belonio", "rice husk", and "gasifier". If all you want is biochar/charcoal look up charcoal retorts or kilns. You could use a belonio gasifier to heat a charcoal retort to make high quality bamboo charcoal. You can still get biochar from the carbonized rice husks.

Andrew Parker wrote:Google "belonio", "rice husk", and "gasifier". If all you want is biochar/charcoal look up charcoal retorts or kilns. You could use a belonio gasifier to heat a charcoal retort to make high quality bamboo charcoal. You can still get biochar from the carbonized rice husks.

One of the best home made TLUD (Top Lit Up-Draft) Retort Hybrid stove designs to make biochar. The JRO makes 30 gallons of char per 90 minute run. The fan assist allows for some moisture in the feedstock;
JRO; TLUD / Retort hybrid http://www.youtube.com/watch?v=Kg95KYrH8PI

Attached is a picture of the bamboo off cuts we have. These are left over from our work. Would it be possible to use these straight in the 55 gallon TLUD?

Moisture content is the biggest enemy of biochar production. If your rice hull or bamboo is moist it will make your production hard work and produce heaps of smoke. 20% moisture content or lower is where you should be. You can char bamboo with a gasifier but you will need to layer it through the chamber and fill the spaces around the bamboo with a dry wood chip. You always need to have a good air flow in the main chamber but you can't allow open gaps or spaces as hot coals will drop to the bottom of the chamber and start to smoulder reducing the available oxygen in the above biomass which will produce poor results. I would use a sledge hammer to smash/crack all the bamboo up a little so you get a better/full char.

This is my Fatboy 1 and 2 batch gasifier systems. The unit is now in it's next major rework which will include an emission oxidiser. http://www.biochar.net/fatboy-gasifier/ and http://www.biochar.net/fatboy-v2-gasifier/

- just my two cents : burning any bio-mass JUST to produce bio-char is a wasteful practice that if done in any other burner than a Rocket stove almost always is going to create more air pollution, please, over a life time the heating, cooking, and hot water needs of one person should generate all the charcoal needed ! Is it really too pie-in-the-sky-bye-and-bye to suggest a Bio char producing co-op if much more charcoal is needed ! Pro-AL

Allen,

I believe this thread is about converting waste into a usable commodity. Certainly it would be great if the volatile gases can be utilized, but that is not always feasible. Making char(coal) cleanly (relatively) is the next best thing.

The rocket design is not the do all and end all in stove efficiency. A 3 stone fire can outperform a rocket stove, and has in testing, depending on the variables. I am not poo-pooing rocket stoves, but I think it is a mistake to become married to the design.

Normally, if you are producing charcoal with a rocket stove, you are doing something wrong.

Gasifiers are very clean burning, more so than the rocket design, and they can be designed to produce char or burn everything to ash.

Theoretically, a rocket stove can be designed as a kind of gasifier (or perhaps more appropriately, a smoke burner).

To answer your last question, Yes.

I don't like to use the term 'burn' when referring to making biochar. I carbonise it using interrupted combustion and a wet quench which produces a much higher quality biochar than wood coal from a fire. The process also creates very little ash. Most of the carbon from the biomass is converted into a graphitic structure which is chemically different from it's original organic structure and research suggests it will last 1000's of years in the soil. The woody biomass I use would in general rot and break down with in 12 months releasing it's stored carbon and volatiles back into the atmosphere. The production of Biochar just speeds up the process and captures a high percentage of that carbon and converts it to a fixed or recalcitrant carbon.

The process of gasification is to cleanly burn the volatile (smoke) gases produced by the charring process. The development of my open source fatboys has been to refine the air fuel mixtures and increase flue turbulence which reduces process emissions. There is nothing stopping you from cooking and or heating water while running a biochar making gasifier.

I run a company called Black Earth Products which produces Biochar commercially, our continuous technology produces very little in the way of emissions and we use our excess heat energy to supply another industrial business. My feedstock is by-product from a sustainable timber milling company. Biochar production can be done right.