(344f) Efficient Conversion of Ethanol to Acetaldehyde with Induction Heating
AIChE Annual Meeting
2023
2023 AIChE Annual Meeting
Topical Conference: Decarbonization of the Chemical Industry through Electrification
Decarbonization by Electrification: Reactors & Reactions 3
Wednesday, November 8, 2023 - 9:35am to 9:53am
The utilization of renewable biomass as an alternative resource has received great attention to relieve the reliance on fossil fuels, which can lead to the emission of greenhouse gases causing global warming. Besides, process heating from the combustion of fossil fuels in many industrial applications is also one of the largest sources of greenhouse gas emissions. Ethanol is a sustainable resource from biomass fermentation, and its non-oxidative dehydrogenation is a vital source to obtain H2 and acetaldehyde, which is a key intermediate for producing acetic acid, ethyl acetate, n-butanol, and 1,3-butadiene. Supported Cu catalysts have been reported to show excellent ethanol conversion and selectivity to acetaldehyde at 280 ËšC. Since ethanol dehydrogenation to acetaldehyde is highly endothermic, a higher temperature is needed to increase the conversion efficiency. However, this can lead to uneven temperature distribution in the catalyst bed, decreasing the selectivity to acetaldehyde resulting from the undesired side products.
Such problems can be solved by applying induction heating (IH). IH is proven to be an alternative heating method for chemical reactions using a varying magnetic field and is considered a sustainable heating method due to the possible direct usage of clean energy, such as wind, solar, and hydropower. Although being explored in various applications, from cancer treatment in the medical field to metallurgic manufacturing on an industrial scale, IH hasn’t been studied in the catalysis field until recently. In our work, we apply IH to ethanol-to-acetaldehyde reaction with physically mixed Co powder as the susceptor in the catalyst bed to provide heating directly to the catalyst. Our results show that ethanol conversion by IH is 1.7 times higher than that by conventional furnace heating at a temperature as low as 215 ˚C, suggesting the high production and energy efficiency of using IH. When the reaction temperature was increased to 245 ˚C with the furnace, the resulting conversion matched well with that obtained with IH at 215 ˚C, showing that IH significantly improves the energy efficiency by lowering the reaction temperature by 30 ˚C. The ethanol-to-acetaldehyde reaction by the IH and furnace heating showed comparable activation energies of 24.1 kJ/mol and 19.77 kJ/mol, respectively. In addition, reactions with IH and furnace heating show similar acetaldehyde selectivity of 80% from 215 ˚C - 245 ˚C, showing that the external magnetic field (MF) doesn’t affect the active sites on the catalyst. To study and further improve the catalyst’s activity with IH, we provided a model in COMSOL Multiphysics to simulate the temperature distribution and design the configuration of the catalyst bed. The temperature gradient along the reactor length was decreased to 1.5 K with the new design. In addition, the energy consumption was only 145 W compared to 435 W with the old design. The new configuration significantly increased the conversion, maintained the selectivity, and slowed down the deactivation by almost two times. The model provided a method to design the catalyst bed configuration and predict the energy consumption with desired product and energy efficiency.
Such problems can be solved by applying induction heating (IH). IH is proven to be an alternative heating method for chemical reactions using a varying magnetic field and is considered a sustainable heating method due to the possible direct usage of clean energy, such as wind, solar, and hydropower. Although being explored in various applications, from cancer treatment in the medical field to metallurgic manufacturing on an industrial scale, IH hasn’t been studied in the catalysis field until recently. In our work, we apply IH to ethanol-to-acetaldehyde reaction with physically mixed Co powder as the susceptor in the catalyst bed to provide heating directly to the catalyst. Our results show that ethanol conversion by IH is 1.7 times higher than that by conventional furnace heating at a temperature as low as 215 ˚C, suggesting the high production and energy efficiency of using IH. When the reaction temperature was increased to 245 ˚C with the furnace, the resulting conversion matched well with that obtained with IH at 215 ˚C, showing that IH significantly improves the energy efficiency by lowering the reaction temperature by 30 ˚C. The ethanol-to-acetaldehyde reaction by the IH and furnace heating showed comparable activation energies of 24.1 kJ/mol and 19.77 kJ/mol, respectively. In addition, reactions with IH and furnace heating show similar acetaldehyde selectivity of 80% from 215 ˚C - 245 ˚C, showing that the external magnetic field (MF) doesn’t affect the active sites on the catalyst. To study and further improve the catalyst’s activity with IH, we provided a model in COMSOL Multiphysics to simulate the temperature distribution and design the configuration of the catalyst bed. The temperature gradient along the reactor length was decreased to 1.5 K with the new design. In addition, the energy consumption was only 145 W compared to 435 W with the old design. The new configuration significantly increased the conversion, maintained the selectivity, and slowed down the deactivation by almost two times. The model provided a method to design the catalyst bed configuration and predict the energy consumption with desired product and energy efficiency.
IH significantly improves the efficiency of ethanol-to-acetaldehyde reaction, with the well-mixed Co powder providing the heat directly from inside the reactor, eliminating the heat transfer difficulties, quickly responding to the local temperature drop due to the highly endothermic reaction, and maintaining the stable reaction temperature. Therefore, it has great potential in highly endothermic and exothermic reactions, reducing carbon footprint, and further applications in producing value-added chemicals.