Friday, November 20, 2020
Separations Division (02) (PreRecorded+)
The development of efficient materials and processes that can concentrate and oxidize volatile organic compounds (VOCs) from flue gas streams in a hybrid adsorption-reaction system provides a cost-effective alternative for current VOCs disposal technologies. With the purpose of reducing catalyst inventory needed for oxidation of VOCs and the amount of heat/energy needed to regenerate the adsorbent, combining separation and reaction in a single unit operation is expected to improve the overall performance of VOCs emission control systems while addressing the drawbacks of the current abatement methods. In this study, the performance of a series of mixed metal oxides (MMOs: TiO2/SiO2 and ZrO2/SiO2) in a temperature swing adsorption-reaction (TSAR) system for abatement of aromatic hydrocarbons as model VOCs was investigated through experimental and modeling studies. The TSAR consisted of three steps, namely, adsorption at 25° C, heating/desorption/oxidation at 250° C, and cooling back to 25° C. The adsorption isotherms were obtained experimentally at 25° C and used to estimate equilibrium adsorption parameters. The actual adsorption-oxidation runs were performed to fit the concentration profiles predicated by gPROMS models. From simulations, the process performance metrics such as VOC removal efficiency, VOC conversion, product yields, step times, cycle time, throughput, productivity and energy consumption were analyzed to determine the optimum operating conditions for the hybrid VOC abatement TSAR process. Post chemical analysis were also performed to determine coke formation after oxidation experiments. The detailed experimental-theoretical analysis provides a basis to rationally design integrated separation-reaction processes in cyclic fashion for VOCs emission control.
