Big biochar stove in action again

Here's the hot shot of the day... charring a post on top of our big Elsa stove using as biomass source the trimmings of the same grapevines where the biochar that was produced was then eventually deposited! Nice closed cycle of Carbon...

Check out the short video-clip with my little helper on the site!

Biochar in the vineyard

Today, we have to get a chance of good weather before the next upcoming forecast rains: it's time to do some biochar in the vineyard... using some of the chopped up branches of grapevines that have been drying in the last days. I guess it counts as one of our special homeschooling days.



The preparation is a bit tricky since we have to prepare everything, loading the little car we have available at the moment and reach the spot: do the all thing then... pack up everything and get back home.

An interesting discovery: my first wood vinegar

One day, after doing the usual dry quenching of the super hot biomass that I had pulled out of my biochar making stove, I noticed some sort of a stain on the floor, like a print of the container used for the quenching... but like if there was something wet. Indeed, under the metal plate that I used as a lid of the container there was some condensation. Very interesting: what could have that been??? 

Further tests while a stove is growing

In these days, as we are gearing up for the next festival where I will be able to organize another biochar making workshop, I have started testing my stove a little bit more closely, with a chronometer and an electronic scale. In this way I hope to get some deeper insight while I size up the Elsa design to burn bigger chunks of wood for a longer time.

  

This is the combustion chamber on the top, all connected using a 5 liters recycled tank, a tomato can and some roofing metal sheet. In my idea, the top "mushroom" chimney it's all going to hold tight together so when I have to open it to do the quenching (possibly again without using water, just by chocking the hot charcoal in a proper airtight container) it's going to be easier and less dangerous...

Detail of the inside of the chimney, with the usual cuts and blades to mix secondary air with the smoke coming from below. 

I have also started weighting how much biomass I put inside and how much charcoal comes out at the end: this is an important proportion to check the whole process and to imagine what to expect while sizing it up. With the present stove, I can load about 60-65 grams of biomass and in a couple of burns I got 9 and 8 grams of biochar, which is less than what I was expecting, but considering that the type of quenching return super light and dry biochar maybe it's alright on these small quantities.

 

Also I have started checking about the speed of the whole process: with the super light biomass that I am using (used chopsticks and small twigs) I can get only to about 10 minutes leaving the primary air always open. In this test I have tried to close the inlet of primary air putting some small rocks all around the base of the stove, where the air comes in from underneath. In this way I was able to arrive to almost 12 minutes and in proportion it's already a good improvement. I have also checked the weight of my biochar volume unit (a tomato can), so that now I know how much biochar I have dumped around in the bush or handed out to some people: it's 35 grams.

  
Now I need to keep producing a bit more biochar and find a good location for a bigger deposit: surely there are many areas nearby that can benefit from it! Keep going on...

A charcoal pit and a biochar stove

Here is a long series of pictures taken during a bamboo charcoal workshop held by an elder wizard during Yamauto festival 2013. The whole process is very simple and straight forward... but unfortunately it has some downsides too, in the loss of biomass, leftover ashes and possibly *very* bad emissions at some point.
Perfect opportunity to display and show my improved biochar making stove. Many people came along and were able to grasp the basic concept by watching it happen.  

 At the beginning a shallow square pit is dug out, as big as the corrugated sheet that was gathered to cover it at the end of the process. A small fire gets started in the center of the pit, using the most dry pieces first then adding whatever other pole, even the most wet ones.

As the fire grows bigger, all the humidity of the bamboo boils out in steam. Several loud sounds like gunshots happen as the bamboo sections crack open in the fire... 

We keep adding more and more bamboo, building up a quite big and hot fire. Then when every pieces is burning... we put the fire down doing the quenching by pouring various buckets of water all around the inside of the pit. 

Soon after doing the quenching we cover all the pit with the roofing sheets making sure that there is a good overlap between each piece, then sealing the whole thing with soil so that no smoke is coming out. 

So it's done! After a couple of days the heat goes down and the pit it's ready to be opened to take out the charcoal left. The soil used to seal the top could be reused (I don't know if it will though...) as well as the pit.
On the side of this ancient practice, I laid down my stove set explaining the main features and the substantial difference of approach: (1) trying to have the cleanest emissions as possible, (2) trying to reduce the ashes to zero (meaning no waste of biomass) and (3) use the energy of the process to cook or to heat water.  

My hand made Elsa-stove replica worked quite well, standing on the side of the pit attracting the interest of everybody, being obviously something completely different.

Here are some of the most keen and grateful participants of the workshop that gathered at some point maybe about 20-25 people. Thank you all for watching and putting up with my broken-japanese language and weird foreigner accent... maybe you all carry within the perfect flame of Pyrolysis!!! 

Still life with biochar: on the lower right corner the bottom of the stove is upside down, showing the hexagonal pattern that I chose to make... improving a lot since the very first test. Now getting ready for sizing it up ;)