Work Update

[Work Update]: Fuel Cambodia - Coconut Baking (Fuel Briquette Prototyping Process) - July 2018

Steven Deng
Steven Deng | 8 months ago | in Sustainable Fuel Consulting

The fuel team in Cambodia proceeded to create a prototype of a biomass waste charcoal briquette to get an idea of the manufacturing process and for initial testing on effectiveness (heat transfer and burning time). These prototypes would also be used for offer testing (to test if villagers like the idea we're developing). Our prototype briquette was made out of coconut husks found on a trailer driving through town. It was obtained free of charge, the only cost being the bags needed to carry them. 

The process is as follows: 

1. Creating the kiln - we obtained an oil barrel for 5USD from a gas station and cut holes in it using a drill according to the document attached (square hole on top of the barrel and 9 holes on the bottom of the barrel). 

2. Carbonising the biomass - the barrel was filled up with all the coconut husks we could find (which wasn't so much that it restricted airflow) whilst a large stick was placed through the middle.The barrel was then placed on stacks of three tiles so it was standing off the ground.

Flammable material (dry grass) was poked through the holes on the bottom of the barrel. A fire was lit underneath the barrel and allowed to spread throughout the barrel. The result is shown in pictures. Allow it to burn for 10 minutes before the smoke turns darker. Then we covered the square hole on top of the barrel with a tile. The barrel was taken off the stacks so that it was touching the ground 

Dirt and mud was then used seal any air into the barrel. The barrel was left for 3 hours for the coconut to carbonise. 

3. Making the powder - the coconuts were then collected from the barrel after carbonization. Non-carbonised biomass was removed (non-black or non-brittle). We then crushed the carbonised matter by manual means (hands, feet etc) until it became powder. 

4. Preparing the binder - Corn starch (from the supermarket) was added to boiling water and put into a container. This mixture was then poured over the charcoal powder and mixed by hand. Sawdust was also added to the mixture to act as an accelerant (shortens heating time of the final briquette). The final mixture was tested by compressing and observing if it would fall apart. It was ready if it would stick together. 

5. Pressing the briquettes - the mixture is placed into the briquette press in sizes that fit the press (the briquette press was engineered from a caulking gun, a PVC pipe for the mould and a hose clamp; details are available in the attached file). The press was then activated and pressed until all moisture possible was squeezed out.

6. Drying - Briquettes were to be dried by sun for at least 2 days (ideally a week). However, we were impatient and decided to dry the briquette by placing them in a cooking pan over the New Lao Stove (clean up was not pretty). The briquettes are then ready to go.

edited on 6th September 2018, 00:09 by Justin Hakeem

Jess Riley 8 months ago

Status label added: Experiment adopted

Reply 0

Ben Disher 8 months ago

Love the pivot guys!
How many briquettes can this process roughly create with the full 16kg worth of biomass? How many do envision yourself needing in order to get out into the villages for testing?

Reply 2

Thomas de Heus 8 months ago

It's tough to say as our hand briquette press is a very temporary prototyping option and was inefficient to use, so we only pressed the amount we needed to test in the final week of project. We had 2/3's of a 55 gallon drum of coconut husks which gave us around 30 or so 40mm diameter, 5cm long cylindrical briquettes (note that this wasn't all of the coconut husk charcoal powder). With a full drum and more efficient pressing process, it's more than feasible to create enough in a single batch to conduct extensive testing with. The guide we based our process off estimated about a 75% reduction, so 4kg of charcoal for the 16kg of biomass. This is definitely dependant on the biomass used however.

We conducted stove tests with many them and found them to work better than expected for a first prototype. Our offer testing this week has involved going out with the briquettes and showing them to households to see the interest in the product. Those who are cooking at the time are given one to test in their new lao stove while we are there, and the fact that the briquettes work so well and are made from coconut waste has impressed every single person so far.

So for testing with customers a large amount isn't needed and hence why in this month we were able to get away with such a small scale prototyping making process. For future months expanding on this should be a focus, as the positive reception to the briquettes has us feeling very optimistic and testing should be taken further. The production process can definitely be improved upon to be made more efficient, paving the way for more extensive testing with customers with a range of different biomass briquettes. Very exciting!

Reply 3

Alexander Teicher 8 months ago

Awesome idea using coconut husks!
For the offer testing, is there a planned method to standardise these tests to gauge responses from villagers? What sort of data would you be looking at collecting through these tests and what would constitute enough of a positive response to suggest that these potential customers would buy the new briquettes? I would assume that adoption would not be difficult as charcoal seems to be widespread. Have you gained insight into how much people are currently willing to spend on fuel sources as an indicator to what kind of market size there might be?

Obviously it is early days looking into briquettes but how are you planning to compete with existing products? Can you differentiate on price, quality, emissions etc. I think Nic asked about this in the work update comments too so I will keep an eye on that too.

Really interested to see results from this testing and where this can go over summer!

Reply 0

Thomas de Heus 8 months ago

Our initial offer testing has been focused on whether customers would purchase coconut waste briquettes over traditional charcoal, and if so what price they would be willing to pay.

Responses have been positive across all 25 housholds, with every single person saying they will purchase it if it's cheaper and they are happy with the quality of the charcoal. Those cooking were given a briquette to test with in their stove, and everyone was impressed with how well it worked. We're aware that saying they'll buy it and actually buy it is a different story, but initial results are very promising.

~15kg bags of charcoal are sold for around $3.25USD and housholds have constistently said they would purchase our bio-waste charcoal if it worked just as well (we know it's better) and was around $2.5 per bag. With proper compression we know that our product will burn for longer than traditional wood charcoal, meaning these 15kg bags will last longer for customers as well. Many customers expressed an interest in initially buying a 1kg bag to test the quality of the product, which currently sells for around 37c for wood charcoal.

The three differentions customers have outlined is price, quality and the environmental benefit. They understand the negatives of deforestation and appreciate the use of waste which clutters the streets of villages. This was surprising and very exciting to hear being brought up.

Offer testing needs to be taken further over summer, with 75 more households as the goal. With such positive initial results, as you said it will be really important to have a method to standardise the results with a consistent method.

Reply 1

Justin Hakeem 7 months ago

Status label added: Work Update

Status label removed: Experiment adopted

Reply 0