I'm one of the new ones here so I might as well jump in with both feet!
Since you seem to love the rocket stove and so do I, I think it's grea.t You see I live the the north of canada where it gets snow 6 months and -40c so I spend a lot of time thinking about heaters.
Anyways I'm also interested in bio-char but only made in the clean burning way as in a gasification stove. First I wish to say that if there is a way for us to reduce co2 and build soil which could then grow trees better and faster that's what I want to do.
I think I have an idea for how to build it. Sorry for the crappy drawing.
So, If this doesn't seem to make sense....
Center pipe is heat riser in typical RMSH. It is fed directly through the center of your gassifier unit (a 30 gal...ish drum barrel). Then tees off before getting to the top, it is channeled into outer 55 gal drum barrel.
It makes sense to wrap exhaust around gassifier for efficiency. Less radiant heat is lost from gassifier chamber and exhaust gasses have 2nd chance to heat up the chamber with greater surface area.
Gassifier chamber (G-Chamber) is 30 gal drum with tight fitting lid and syngass escape port.
Idea: Direct a small amount of syngass from G-chamber into burn chamber where wood is. Greater heat=Greater efficiency
Another idea..... Put entire unit described as above into yet another LARGER barrel for cooking purposes. It too would need a removable lid, and syn gas port would have to make a 90 degree turn out of the side of larger barrel.
Only reason for the larger barrel is because surface area in previous design is very limited.
I favor taking an existing woodgas stove design and modifying it somewhat to be even more efficient. Here's the idea.
I really like the concept of the biomass-woodgas stove, especially its by-product of biochar. Not only does it allow very cheap/free cooking, but the cooking is about as non-polluting as possible and the biochar allows for long-term soil enrichment (the carbon sequestration is cream on the cake). I have looked at the Biolite website http://biolitestove.com/ where they have a rocket stove that has its fan powered by an attached thermoelectric generator...which also produces enough extra electrical power to charge various devices via a USB interface. Soooo, the thought arises that one could redesign a woodgas stove to include the TEG and its power-production capabilities. That would be the best of all worlds: ultra-clean and cheap heat for cooking, plus no batteries or electricity needed, plus the production of biochar, plus extra power to charge phones, tablets, etc. Heck with a big enough TEG and stove, you could charge a deep-cycle 12V battery, and power all kinds of things with it. I am no engineer, but it seems that if one heat-producing stove can have a heat-powered fan swirl incoming air around via a TEG to make the stove more efficient, so can another stove…and why not make some biochar in the process (unlike a rocket stove, that gets so hot that it leaves nothing but ash)?
And if you could adapt some type of water pasteurization unit to fit on top of the woodgas stoves, then WOW! The stove would be a complete dream for preppers or anyone who knew they’d be away from civilization for a while – heat and water, not to mention some bonus electrical power (maybe for charging a Sat phone, if you're that far from everything), and all you’d need is a means to start a fire. In addition to all of the traditional methods one could even use a fresnel magnifier and some sun to ignite paper or some dry grass, you wouldn’t even need matches, lighters or any other non-renewable means.
I'm not sure I follow your drawing. It could be similar to what I was thinking. Below is what I was imagining. It would be very cool if you could build an Organic Rankine Cycle system like http://www.infinityturbine.com/ORC/ITmini_ORC_System.html into thermal mass to generate some electricity. I imagine producing bio char while heating and lighting a greenhouse.
Hi all, this is my UNPROVEN process submission for RMH toward generating charcoal. This may have already been invented & proven, I just haven't seen it like this, I know that many have proven the RMHRocket Mass Heater, so I'm hopeful of this add on charcoal making process. I'm hoping to build this outside the house initially at least, and my hope is that I would be able to have several portable 35 gallon barrels, each for different stages in the charring process. The first 35 gallon barrel is 'cooking' atop the RMH 55 gallon burn barrel. As the pix shows, the syngas is simply piped via a removable/flexible hi-heat hose for additional fuel to use in the RMH burn tunnel. The second 35 gallon barrel is staged nearby for cooling, while the charcoal within continues to cook on its own, this 'cooling stage' continues to emit syngas, and should be also piped to the RMH burn tunnel intake manifold. The third 35 gallon barrel is staged nearby also, it is being filled with dry raw wood products. This third 35 gallon barrel is rotated with the other barrels, based on the stage of the charcoaling process.
Also my picture does NOT show a 'working/cat walk area' that is located above the RMH, because the lifting and emptying of the filled portable 35 barrels should be such that if the barrel is dropped or knocked over, the distance to the platform is not much. The catwalk would be such that the operator can roll filled barrels into and out of place, upon the top of the RMH 55 barrel heat source.
Also my picture does NOT show the staging areas of the various barrels, which could be racks just above the RMH exhaust pipes, so that the staged 35 gallon barrels can be part of the mass heat absorption, to help dry the fresh supply wood. And to also absorb some of radiant heat given off by the 35 gallon barrel during the cooling process. Like perhaps another special 35 gallon barrel LID, that has (2) manifold pipes on the lid, one connected via flexible pipe to 'the cooling barrel' and the LID is placed on the raw wood barrel, and the second pipe on this special lid...is connected to the burn tunnel manifold, thereby drawing hot gases off the cooling barrel, drawn thru the raw wood barrel (to dry & increase the raw wood temperature), and then onto the burn tunnel to be incinerated.
Also I have thoughts of a non-flammable throw rug to be hitched around the 35 gallon & 55 gallon barrels at same time during the charcoal cooking stage, this is because of outdoor wind & temperatures and rain problems.
This second picture might show alittle better how the loaded 35 gallon barrels are staged, one 35 gallon barrel containing/baking char atop the 55 gallon barrel, heated with the RMH. Other filled 35 gallon barrels are staged atop the exhaust heated mass bench, this pix shows barrel cradles molded into the top of the mass bench. I hope this pix demonstrates the plumbing of the syngas from the portable 35 gallon barrels to the RMH burn tunnel, the auxiliary supply of syngas is from the baking process occuring within the 35 gallon barrel, as the RMH is fired properly from small sticks of wood in the wood burn tunnel, and as the baking continues, syngas is emitted thru the blue pipe into the burn tunnel. Of the various 35 gallon barrels in the staging area, cradled in the mass bench, one of those has already been baked for various times, and yet the very hot emissions from the baking process can be safely routed into the next staged barrel of dry raw wood. From that dry wood barrel the hot gases & moisture might return via the horizontal blue hose to the burn tunnel for incineration in the RMH. I don't expect to use any blowers or fans. I'm hoping for very little emissions from the whole process.
I've also been contemplating producing improved baked charcoals, changing the process alittle nearing the batch baking completion. Water may be added thru the pipe in the lid, thus quenching the coals, breaking & 'activating' the charcoal within, once allowed to cure with steam for a time, the 35 gallon drum may be returned atop the RMH burn barrel, for final heating to drive off remaining toxins, water, whatever. The flexible syngas hose may be left disconnected while the steaming process is performed, to prevent damping the RMH burn tunnel with moisture heavy steam. I'm hoping for true activated charcoal as the final product, to be used as a very coarse water filter media, large particles 3-4" thick and 20" long.