BIOCHAR PRODUCTION FOR CARBON SEQUESTRATION

At Monash Carbon Capture & Conversion, we aim to use biochar for carbon sequestration purposes. We are aiming at the agricultural sector as it increases plant productivity and reduces nutrient leaching.

1. PYROLYSIS OF BIOCHAR 

Biochar production is a method of long-term carbon sequestration relying on the process of pyrolysis in an oxygen limiting environment. In our proposed solution, microalgal biomass feedstock will be used in biochar production. Through slow pyrolysis and torrefaction, we aim to maximise the solid yield of biochar for agricultural and carbon sequestration purposes.

3. FAST PROLYSIS PYROPROBE TESTING

Initial testing for the viability of pyrolysis to produce sequesterable biochar was performed. Results suggested an O:C ratio of 0.6 can be obtained between 300-400°C and would increase as temperature increases, but consequently the mass of the biochar also decreases as temperature increases. This means a balance needs to be achieved to obtain stable biochar that can still meet a good sequestration rate.

Figure 1: Biochar Testing for soil

2. END TO END SOLUTION

The end to end solution involves the biochar team acting as an intermediary between the forestry and microalgae team. The long term energy is sourced from the forestry team’s wooden offcuts via the BECCS Power Plant and biomass feedstock is sourced from the microalgae team. The produced biochar can then be used as a soil supplement and increase the growth rate of high CO2 conversion plants grown by the forestry team.

Figure 2: Graph of CHNS Analysis

4. FUTURE TESTING

Currently, our investigation involves looking into which potential methods which offer a better solution to our long-term goal. This includes primarily slow pyrolysis and torrefaction as means for future experimentation, as our current data suggests that longer residence times and lower temperatures than conventional pyrolysis offer greater biochar yield whilst maintaining our desired O:C ratio. Our upcoming experiment aims to use a Relative Flash Volatilisation (RFV) rig to emulate slow pyrolysis at temperatures between 280-310°C, with the aims of achieving better results than our first round of experimentation.