High surface area porous carbon from cotton stalk agro-residue for CO2 adsorption and study of techno-economic viability of commercial production

Abstract

Cost concern of solid CO2 adsorbents has encouraged to synthesize porous carbon from surplus biomass. Porous carbon was derived from abundantly available, non-fodder cotton stalk agro-residue via single step KOH + alum chemical activation. Derived carbon exhibited notable BET surface area of 2695 m2/g, and CO2 adsorption capacity of 6.9 mmol/g at 273 K/1 bar and 4.24 mmol/g at 298 K/1 bar respectively. The isosteric heat of CO2 adsorption at zero loading was 23.5 kJ/mol and CO2/N2 selectivity was calculated to be 42 at 273 K. Techno-economic model of a plant producing 2 tons/day of porous carbon suggested levelized cost of 284.38 ₹/kg (3.78 USD/kg), net present value of 54.79 million ₹ (0.7 million USD), internal rate of return of 39.15% and payback time of 3.47 years. Monte Carlo sensitivity analysis of feedstock price, porous carbon selling price and activating agent recovery was studied. This work opens up possibility of CO2 capture by porous carbon obtained from non-fodder agro-residues through cost-effective methodology particularly for post -combustion CO2 capture.