Removal of highly concentrated toluene from flue gas by an anode-supported solid oxide fuel cell reactor to generate electricity

• SOFC to remove highly concentrated toluene.
• Excellent power performance is obtained at an intermediate temperate of 650 °C.
• The power performance increases when flow rate and toluene concentration increase.
• The generating efficiency of the cell with toluene as the fuel is evaluated.

Toluene, a typical volatile organic compounds (VOCs), is raising growing concern due to its harm to human health and atmospheric environment. However, it also can become a fuel for that C–C and C–H bonds contain considerable chemical energy. In here, we utilize a solid oxide fuel cell (SOFC) reactor to degrade toluene as an environment pollutant and to take full advantages of its chemical energy simultaneously to generate electricity. The scanning electron microscopy (SEM) results show a uniform three-layer structure of the cell and the porous morphology of the anode. Energy dispersive spectroscopy (EDS) illustrates the atomic ratio of the fuel cell and reveals a diffusion layer of the cell between the cathode and the electrolyte with an atomic ratio of Ce:Gd:O = 5:26:69. In the reactor, the toluene can be removed from a low temperature of 600 °C. It can be totally removed under 650 °C and obtain a power density of 14 mW/cm2. The removal efficiency can reach 94.19% under high toluene concentration of 1.874 × 105 ppmv and a temperature of 650 °C and obtain a power density of 14 mW/cm2. However, it decreases as the flow rate increases to 200 mL/min. With the initial concentrations varying from 1.243 × 105 ppmv to 5.472 × 105 ppmv, the cell efficiency declines from 29.93%, 20.89%, 19.13% and 19.61% to 16.06%, 5.030%, 8.297% and 7.874% as the flow rate increases from 50 mL/min to 200 mL/min. The impedance spectra are analyzed for the mechanism of cell performance. The economic analysis shows that it can save energy not only in that it generates electricity while removing toluene but also in that the heat it releases can well help preheat the cathode air.

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