Those working in the field of bio-energy regularly come across the term Pyrolysis. What does it mean, and what are its benefits?
Pyrolysis refers to heating of biomass to a high temperature, but with no supply of air.
Under such circumstances, the biomass gets converted to a mixture of fuels – charcoal (solid), organic gas (gas) and oil (liquid). Thus, pyrolysis is a unique process that, starting with biomass, results in fuels in all the main physical forms – solid, liquid and gas!
Depending on the temperature variations during the pyrolysis process and the speed at which the process is completed, the percentages of charcoal, gas and oil vary.
Let us briefly look at each of the three end products of pyrolysis:
- Charcoal – this can be used as a high calorific value fuel, or used as a feedstock to make activated carbon from which a number of natural filtration products are made. Charcoal is the main end product for most pyrolysis processes worldwide.
- Oil – This is a thick oil similar to furnace oil, with calorific value about half that of gasoline or diesel. This oil is suitable for use in some heating applications, especially in applications where furnace oil is currently used.
- Organic gas – This forms only a small component of the by products from the pyrolytic process; this is a low calorific value gas that could find some applications for heating or small scale power generation.
Pyrolysis is thus an effective way to convert biomass, especially waste agricultural waste and such, into useful fuels and products. (Pyrolysis can also be used to convert plastic to oil – see here for more)
In the past few years, I have met many entrepreneurs and businesses working in the pyrolysis sectors – some of them focus on charcoal as the end product and the others, especially those using plastics as the feedstock, typically focus on oil as the end product. Based on what I have seen, it appears to me that the charcoal / biocoal business appears to be doing much better than plastics-to-oil currently.