Catalytic oxidation of n-hexane in a fluidized bed with modified flow

• Published in: Journal of cleaner production Vol. 402; p. 136848
• Main Authors: Żukowski, Witold, Migas, Przemysław, Żurek, Marta, Wrona, Jan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 20.05.2023
• Subjects: Baffle; Bubble size; Fluidization; MnO2/Al2O3 catalyst; VOC; MnO2/Al2O3 catalyst; Bubble size; VOC; Fluidization; Baffle
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2023.136848

The results of the n-hexane oxidation process in a fluidized bed reactor with a catalytic bed are presented. Additional baffles were located in the fluidized bed reactor, the purpose of which was to modify the flow in a way to increase the efficiency of the process, while maintaining constant values of the residence time of the reactants in the fluidized bed. The characteristics of a reactor without flow modifications and those of reactors using three types of baffles, two vertical and one of horizontal were compared. It turned out that the best results were achieved by a reactor using horizontal elements in the form of grids. Thanks to the use of a set of 3 meshes, it was possible to significantly improve the conversion of n-hexane to carbon dioxide. For example, at 350 °C it is possible to improve the full conversion of hexane from 85 to 97%. The oxidation efficiency is improved by reducing the size of the bubbles, which was visually confirmed. Additionally, the analysis of recorded pressure fluctuations was used to analyze flow of bubbles in the nonmodified and modified fluidized bed reactors. A relation between the recorded values of pressure fluctuations and chemical effects in the form of emissions of incomplete combustion products was shown. Baffles that improve n-hexane conversions also reduce the amplitudes of pressure fluctuations. In addition, the calculated values of bubble sizes in the reactor without modification and in the reactor modified with elements in a horizontal system are shown. •MnO2/Al2O3 catalyst was prepared and used in the modified fluidization bed reactor.•Baffles reduce size and velocity of bubbles that improve the oxidation efficiency.•Introduction of selected baffles to the fluidized bed intensifies gas-solid mixing.•Pressure fluctuations were reduced by baffles application.