Hudson Beare, LT2
Novel Activated Carbon Materials Development for Various Industrial Applications
Ajay K. Dalai (and Sepideh Shahkarami)
Canada Research Chair in Bioenergy and Environmentally Friendly Chemical Processing, Catalysis and Chemical Reaction Engineering, Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, Canada
Professor Dalai has focused on the development of activated carbon from biochar, coal and other carbon sources for various industrial applications such as mercury capture, hydrogen sulfide capture and carbon dioxide capture. Research on the CO2 adsorption on activated carbon (AC) adsorbents has gained significant interest due to their low cost, low regeneration energy, and eco-friendly characteristics. The current seminar is focused on the systematic development of AC using different types of biomass, pyrolysis conditions and activation condition to prepare adsorbent with tailored textural properties for CO2 separation under simulated flue gas conditions. The work is divided into two phases. The first phase of the work was focused on the synthesis of activated carbon using steam, CO2 and potassium hydroxide (KOH) as activation agents and evaluation the CO2 adsorption performance under a range of temperature and inlet CO2 concentrations (CCO2). The KOH treated activated carbon had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure under the optimized experimental conditions of 30 mol% CO2 and 25°C. However, all prepared activated carbon samples had a poor performance at high temperature (~65°C) and/or low CCO2 (~10 mol%). The KOH activation conditions in the first phase was then used for the activated carbon preparation using three different types of biomass (forest residue, agricultural residue and animal manure) as precursor and two different pyrolysis processes (fast and slow pyrolysis). The main finding in this phase was that activated carbons have different sensitivity to CO2 separation according to their micro-pore distributions and total pore volume and surface area are not significant factors for CO2 adsorption on ACs. Overall, the pinewood sawdust derived ACs showed the best adsorption capacity of 78.1 mg/g (at 15 mol% CO2 in N2 and 25°C). An isothermal mass transfer model for CO2 adsorption in a mixture of CO2/N2 is developed. The adsorption equilibrium data of CO2 and N2 on KOH activated carbon are determined at 273, 298, 323 and 348 K. The model is used to reproduce the CO2 adsorption breakthrough curves in CO2/N2 gas mixture and can be considered for designing a fixed-bed adsorption process to separate CO2 and N2 using microporous and mesoporous carbon materials.
Ajay K. Dalai completed his B.Sc. (Hons) at S.C.S. College, Puri (Utkal University, India), his B.Sc. Tech. at Nagpur University (India), his M.Tech. at the Indian Institute of Technology (Kanpur, India), and his Ph.D. at the University of Saskatchewan (SK, Canada). Following a Postdoctoral Fellowship at the Texas A&M University and the University of Calgary (AB, Canada), he began his career with the University of Saskatchewan in 1996 as Assistant Professor in the Department of Chemical Engineering, with promotions to Associate Professor in 1998 and to Full Professor in 2002. To date, Dr. Dalai has supervised and co-supervised over 100 M.Sc., M.Eng., and Ph.D. students, post-doctoral fellows, and visiting professors. In 2001, he was awarded a Tier 2 Canada Research Chair in Bioenergy and Environmentally Friendly Chemical Processing and Tier 1 in 2009. In 2007, Dr. Dalai was appointed as Head of Chemical Engineering and in 2009, he accepted the position of Associate Dean of Research and Partnerships for the College of Engineering, in addition to his professorship and supervisory role, and in 2012 as Special Advisor on Energy and Minerals research theme to the Vice President Research at the University of Saskatchewan.