Chemical Reactive Separations In Energy And Environmental Processes

Md Arif Khan, North Carolina Agricultural and Technical State University


The main objective of this study was to investigate the application of chemical reactive separation (reactive separation, advanced oxidation) in bio-oil upgradation and air pollution control. Aspen simulation for reactive distillation of pyrolysis bio-oil for the reactive distillation with n-butanol is carried out using RADFRAC module and UNIQUAC property method by minimizing Gibbs free energy. The binary and ternary interaction and chemical and phase equilibrium (CPE) between the components were studied to determine the azeotropes and homogeneous region of mixture. The conversions for the esterification reactions were found to be 70-90% for various simulated bio-oils, and water was separated from the ester products. All the distillation column parameters such as condenser and reboiler heat duty, number of stages, reflux ratio with different inlet conditions etc., were studied to develop a completely energy cost minimized RD unit. The removal of nitric oxide (NO) from simulated flue gas in a bubble column reactor at atmospheric pressure is investigated using combined aqueous persulfate (Na2S2O8) and ferrous ethylenediamine tetraacetate (FeII-EDTA) systems. 0.1 M persulfate solution with 0.01 M Fe2+ was used as the optimum amount of absorption-oxidation reagents and molar ratio of Fe2+ and EDTA was found to be 1:1 for maximum NO conversion. NO absorption experiments were carried out at 23-70 0C, and comparative NO concentration profiles and corresponding conversion (%) plotted. The results show significant improvement in NO removal compared with thermally and Fe2+ activated persulfate systems (at lower temperature 25-30% and at higher temperature 5-10%) and almost 100% NO conversion can be achieved at 70 0C. The detailed chemistry and kinetics are discussed. Iron species' (Fe2+, Fe3+ and FeII-EDTA) concentrations were measured spectrophotometrically to understand the simultaneous and synergistic relationship between persulfate and FeII-EDTA in NO removal.