Q2. What was the main liquid fraction collected in the ambient receiver?
The main liquid fraction collected in the ambient receiver was two-phase, a pale-yellow/orange aqueous phase separating above a heavy, dark-brown oily phase.
Q3. What was the pressure sensor used to determine the flow rate of the gas?
Pressure sensors were zeroed and the reactor was purged with nitrogen before establishing a steady flow rate of nitrogen as carrier gas; an inlet flow of 0.33 l min -1 was used giving a calculated linear cold flow velocity within the empty reactor tube of 3 mm s -1 .
Q4. How long did the hold temperature last?
The hold temperature was maintained for 60 minutes before the heating was stopped and the sample cooled naturally, generally cooling to below 100 °C in one hour.
Q5. How much does the yield of biochar decrease with temperature?
With increasing temperature, the yield of liquid and to lesser extent gaseous products increases and consequently the yield of the solid product, i.e. biochar, decreases considerably (approx. 10% points) between 350 °C and 550 °C.
Q6. What is the effect of increasing temperature on the yield of biochar?
With increasing temperature, more and more of the total chemical energy in products is contained in pyrolysis gases and liquids, rather then being retained in the solid.
Q7. How much of the current anthropogenic emissions could be reduced?
The global potential for sustainable global biochar deployment has been recently analysed by Woolf et al.[3] , results showed that net emissions of GHGs could be reduced by as much as 1.8 Gt CO2 – C equivalent per year (i.e. 12% of current anthropogenic emissions).
Q8. What is the key parameter to consider in defining biochar production conditions?
As highlighted in the previous section, the stable fraction of biochar is one of the key parameters to be considered in defining biochar production conditions.
Q9. What is the effect of the pyrolysis temperature on the yield of biochar?
It shows that despite the concentration of the stable fraction in biochar dramatically increasing with temperature, the pyrolysis temperature affects the yield of the stable fraction to a much smaller extent (at least for MLS and Pine).
Q10. What is the key missing set of information for techno-economic analysis of biochar?
One key missing set of information for techno-economic analysis of PBS is the lack of systematic and comprehensive data on pyrolysis product distribution (and energy content), especially for slow pyrolysis systems.
Q11. What is the rate of gas evolution in a pyrolysis experiment?
In general, the rate of gas evolution subsided soon after the hold temperature was reached to leave steady flows, only slightly raised above the carrier gas flow.