Step by Step Guide to Making Biochar Briquettes

At re:char, we are die-hard devotees of open-source methodology. We believe that it’s the responsibility of  innovators to document their work and share it with the world. The only way technologies like biochar will scale is through radical openness.

To that end, we offer the below step-by-step guide to producing charcoal fuel briquettes from biochar. Africa’s growing thirst for charcoal and cooking fuel is the leading cause of deforestation in the region. Other charcoal or biochar briquette solutions exist, but few of them produce briquettes that rival the quality and burn time of wood charcoal. We encourage readers to experiment and report back with their thoughts/ideas/innovations. Our only ask is that you acknowledge our work. If you use our images or information in a presentation or report, please credit it appropriately to re:char.

 

Step 1—Produce Biochar.

Our team of charmakers identifies recently harvested sugarcane fields, and contracts with the owner to convert the waste into biochar. In East Africa, sugarcane and maize waste is normally burned in the field, as it has no other value. In-field burning returns approximately 2-5% of the original carbon to the soil and a negligible amount of NPK.  It does little to improve soil tilth, and is considered a major source of particulate and soot emissions in the region.

 

We deliver between 5 and 20 Rutuba 2.0 Biochar Kilns to the field site. Our team harvests the waste, converts it to biochar in-field and bags it into 50 kg grain sacks. The biochar is quenched with water in the field, leaving it fairly moist. It currently takes ~1 week for a team of 10 experienced charmakers to convert 1-2 acres of cane waste into biochar. For reference, a robust cane field can produce between 7 and 28 metric tonnes of waste in one season.

 

Step 2—Produce Biochar Slurry

 

Raw sugarcane biochar is too coarse to produce optimal charcoal briquettes, so it must be homogenized. We use a device called a screw-press to produce optimal biochar slurry.

 

The raw biochar is loaded into the screw press, and extruded as a tube of slurry. Our system can produce ~200kg of slurry/hour. The incoming biochar must be moist, or it will not bind properly. We then transport the slurry to our briquette production site.

 

Step 3—Produce Briquettes

Most commercial screw presses produce a tubular briquette that is too large and too oddly shaped for widespread usage. East African cooks are very conservative and often unwilling to use unusual cooking fuel. To solve this problem, we employ a team of experienced briquette makers to produce optimally sized briquettes. These ladies (and the occasional man) load our handheld hammer presses with a handful of slurry and press it into an ~4cm cube. A team of 6 can produce up to 2,000 briquettes in one day.

 

The briquettes are left in the sun to dry. Once finished, they are ready for use or resale.

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