PYROLYSIS & CARBON BY-PRODUCTS
Biochar, activated carbon, and charcoal are three forms of carbon that share similarities in composition and the way they are produced. The latter is something most people are aware of as a medium for sizzling a sausage or burning a burger. However, many people are not necessarily aware of how charcoal and these other carbon forms are made or their historical importance.
With the world now focussed on carbon and its capture, pyrolysis has taken on the task of sequestration. The pyrolysis of waste woods and organic material captures around 45-60% of the carbon within the feedstock and retains it. Not only does this aid Net Zero aspirations, but it also contributes towards a circular economy through the onward use of materials (as biochars or activated carbon). In this way, sustainable value chains can be created.
When you consider the significant amount of energy generated from this process, the overall picture is very exciting from an environmental and economic standpoint. The energy generated offsets fossil fuel derived energy and further decarbonises the solution whilst offering financial savings.
The RHS describe biochar as “a catch-all term describing any organic material that has been carbonised under high temperatures (300-1000°C), in the presence of little, or no oxygen. This process (called ‘pyrolysis’) releases bio-oils plus gases and leaves a solid residue of at least 80% elemental carbon which is termed biochar”.
Pyrolysis creates a carbon-rich char with increased porosity and surface area. This Carbon-rich char is ideal for enhancing soils due to its ability to harbour beneficial microfauna and prevent nutrients from being washed out of the soil.
Pyrolysis derived biochar has been used for its soil regenerative properties as far back as the Aztecs. In the Amazon, low fertility soils were transformed by the area’s indigenous inhabitants across the region through the addition of charred organic material now termed Terra Preta or Amazonian dark earth. Its introduction into the region helped develop and sustain an advanced agricultural population now estimated at over twenty million people.
The use of biochar in soil also helps prevent the leaching of chemical fertilisers and herbicides by trapping them within the intended soil. Ultimately lowering the quantity and frequency that these chemicals are used while promoting the soil’s natural regeneration.
Charcoal is an “impure form of graphitic carbon, obtained as a residue when carbonaceous material is partially burned, or heated with limited access of air.”
Pyrolysis is an ideal solution for the conversion of organic material into a char in a controlled manner that allows the formulation of chars with specific characterisations. For charcoal, it will hold energy that is released when lit in a barbeque and in this instance, the physical size of the lumps is also important.
In the case of charcoal, which is further burnt as a fuel/heat source, the carbon aspects are less strong, however with a large amount of charcoal coming from South America producing local charcoal from sustainable sources has to be the way forward to protect deforestation and the transports of charcoal thousands of miles by boat. Plastic derived charcoal is also a possibility.
3. ACTIVATED CARBON
Activated carbon is a carbon-rich solid derived through pyrolysis from biomass or other carbonaceous substances such as coal. In the process, a carbon material is also “activated” by processes that greatly increase the surface area of the material, allowing it to capture (or “adsorb”) a larger quantity of molecules. This high adsorption capability allows activated carbon to be effective at removing contaminants from water and air, which is why activated carbon is typically intended for remediation or purification projects.
It is also these properties that have lead to activated carbons increased use in everyday life, toothpastes, face masks, and dietary cleansing pills can be found containing activated carbon as a detoxifying agent.
Activation for activated carbon involves a secondary process where steam is introduced to remove carbon from already carbonised material at higher temperatures. This process opens the pores of the carbon to further increase its surface area.
At our demonstration and research facility, we have run tests on a number of different types of recovered and contaminated wood. Processing conditions include pyrolysis temperature and duration, particle sizing, moisture content, and activation. These can be controlled by the PyroCore process to achieve char that is either graphitic (for enhanced carbon capture) or better suited for agriculture.
To get more information about our specific results or to learn more about our carbon capture technology get in touch with a member of our team at email@example.com
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