NUL Innovation Hub Professor makes ‘Charcoal’ from Clay

Originally published by NUL Research and Innovations

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Image Cred: NUL Research and Innovations

Well it is not “Charcoal” as you know it. That is because it is way better than charcoal. It is not a normal briquette either.

It is a briquette made from clay and plants’ remains by The National University of Lesotho (NUL) Innovation Hub researcher, Professor Sissay Mekbib.

Unlike your normal charcoal, it doesn’t use much energy to make. Yet it retains and releases the heat very slowly, grilling your mouth-watering barbecue to as close as possible to perfection!

“The product will soon hit the local markets as it has already been approved by the NUL Innovation Hub for incubation as a business,” said the ever-passionate Professor Sissay Mekbib.

It is one of the most interesting products in the area of renewable energy in Lesotho. And it is meant to take advantage of Lesotho’s abundant clay deposits, which we hardly ever use.

First, let’s see why we need briquettes and charcoals and why Professor Mekbib’s work is neither a charcoal nor your normal briquette. The normal practice in Lesotho is to burn wood or cow-dung. Professor Mekbib call these primary energy sources.

“The problem with these primary energy sources is that they release a lot of smoke, which is a killer,” he said. “Also, because of high content of water and less compaction of organic matter , they don’t hold heat well.”

So clever people have found some ways to go around this. They turn wood and other plant matter into charcoal.

Guess what they do. They take wood, and heat it in an environment where there is no oxygen. There is no rocket science there. What happens is, when you provide heat without oxygen, a process called pyrolysis or carbonization happens.

Never mind the fancy words.

Pyrolysis and carbonisation means when the wood is heated in the absence of air (oxygen), first water is driven off, then other volatile materials—materials that evaporate easily—leave the wood, but there is no burning. What remains is mainly carbon. Yes, carbon is the main element in plants and it is the one that take part in burning.

Without water and other volatile materials, carbon burns better, produces more heat and holds the heat better.

So there is no magic behind those barbecue charcoals you see or use every day after all!

However, Professor Mekbib is solving one problem that charcoal don’t solve. Remember we said that to make charcoal, you have to burn wood or plant materials in the absence of oxygen. The problem here is the word “burn.”

So to produce a material that is going to burn , you start by heating it!
That heat comes at a cost.

So he resorted to going back to the basics. Remember we said we don’t want to use biomass as it is for the reasons we gave. However, what if we make it dense? That is, what if, the plant particles are compressed together? That is called briquetting (making them into bricks).

Briquetting makes it easy for biomass to be handled (because it is now in the form of bricks). It also concentrates the plant material together, so that you get more energy per lump of plant material. So briquettes may be better than primary energy sources. But briquettes still don’t work as well as charcoal. They still have that problem of water and volatiles.

Herein comes professor Mekbib.

He first takes plant materials and pound them to powder, very fine material. That increases surface area and makes it easy to mix with other materials. He then premixes the plant material with (organic) material that will improve the binding and energy capacity of the briquettes.

But then, this is where it gets interesting. He adds carefully selected and highly refined clay in the mixture. After months of experimenting with formulations and heat performance tests, the good Professor thinks he has got it—he has got it!

Here we are with a material that has the simplicity of briquettes (no pyrolysis and carbonization stuff), and the effectiveness of charcoals, in one file (oh boy! can his briquettes hold heat!).

Set his briquettes on fire and they become red-hot, releasing heat slowly. The professor has many theories behind this masterpiece of a product. It is possible that some heat is transferred to clay which has a high capacity to hold and release this heat slowly.

It could also be that since each plant material is surrounded by clay when heat is applied, the particles are carbonised in the process, releasing more heat than normal, but without a need for expensive preheating!

The Professor is looking to publish this work. In the good old days, that would be the end of it. But, now, thanks to the NUL Innovation Hub, you will see this product in the markets soon.

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