Production Of Activated Carbons From Pyrolytic Char For Environmental Applications

Biomass pyrolysis has the potential to become a major component of future biorefineries, since biomass is cracked to produce gases, liquid products (bio-oil) and solid products (bio-char). In order for the process to be economically feasible, it is necessary to obtain the maximum value from each stream, thus no by-product can be regarded as a waste. Bio-char is normally regarded as a by-product of fast pyrolysis, which is optimized to target bio-oil production. However, there are many potentially attractive applications for it: for example, it can be used for the production of activated carbons, which are the most commonly used adsorbent materials. In this study, a new reactor technology developed at ICFAR, the Jiggled Bed Reactor (JBR) is employed as a fast and reliable tool for the optimization of the production of activated carbons from biomass. Due to its excellent heating system, both slow and fast pyrolysis conditions can be achieved, and activation can be carried out. The results obtained in the JBR show good comparison with larger scale reactors, thus allowing the screening of new pyrolysis and activation conditions as well as different feedstocks in a fast and reliable way. The impact of the type of feedstock, activation and pyrolysis conditions (fast/slow) on the final product characteristic and activation kinetics are studied. Finally, the performance of activated carbons produced in the JBR as adsorbents is evaluated for different environmental applications, such as the removal of ammonia and mercury from wastewater and of naphthenic acids from Oil Sands Process-affected water (OSPW). In particular, activated carbon produced from Kraft lignin is shown to outperform commercial activated carbon for wastewater treatment applications