Biochar or inertinite?

Biochar, char, charcoal, carbonized or torrefied biomass, vegetable carbon are commonly used terms in industry, media and science. Do all these refer to the same thing?

For simplicity let's call this thermally treated biomass, biochar. Due to its untapped Carbon Dioxide Removal (#CDR) potential, especially if used in soils, #biochar is taking the conversations like a storm.

The CDR of chars revolves around permanence or stability; in other words, how long is the carbon sequestered before being released into the atmosphere as CO2? The accepted permanence is around 100 years, but is there more to this?

We know that higher temperatures and longer residence time (measured in hours) result in higher carbon content, Cfix and Corg, and less volatiles and hydrocarbons. The higher the Cfix, the more stable and less reactive, the biochar is, resulting in longer permanence. With temperatures above >500 oC, the expected Cfix in biochar is >80%.

To break it down according to accepted market ready, commercial technology, and the respective process temperatures, there is steam explosion (200 oC), torrefaction (250-350 oC), pyrolysis and carbonization (500-900 oC).

As biochar can be produced from biomass and agricultural residues, which are sequestering the carbon from the CO2 in the atmosphere (CDR), it is a perfect means of Atmospheric Carbon Capture and Storage (CCS), if buried underground.

Now the scientific discussion evolves around the permanence of such storage and here is where the quality and the characteristics of the individual biochar come into play.

Literally, it is the reactivity of the biochar that is the key measure to understanding whether the biochar buried will stay put or whether it will react and partly resurface.

As such the Cfix, the Corg and the volatiles in the biochar are the parameters determining the permanence character.

Now, have you heard of?inertinite?

In nature we find inertinite, a biocarbon that has over time, matured into a material that contains almost no volatile components and resembling graphite or even diamonds.

This inertinite has proven to be a permanent carbon in the earth′s crust and hence it can become the benchmark for categorization of permanence in CCS.

It seems that biochar of very low volatile content resembles the inertinite as it will not release any meaningful number of volatiles anymore.

Here`s the segway to our Green Carbon carbonisation technology! After a decade-long development, in 2015, a fully commercial, industrial facility was built to produce high-quality organic carbon (biochar). Yes, this is a high-temperature, slow pyrolysis plant with operating temperatures between 500-650 oC, residence time of up to 2 hours and an achievable Cfix of 98%!

Perhaps these chars should be called inertinite. :-)

More on Green Carbon in future newsletters.

This article is meant to present other plausible views, ideas and narratives to that of what is mainstream.

Written by: Viktor Radic, dipl.ing.