New Way of Removing Hydrogen Sulfide at a High Temperature: Microwave Desulfurization Using an Iron-Based Sorbent Supported on Active Coke

Microwave was applied to the high-temperature removal of H 2 S by a Fe-based sorbent supported on active coke (Fe 2 O 3 /AC). The influence of the loading content, adsorption temperature, and desulfurization way on the sulfidation properties of sorbents was investigated. N 2 adsorption, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques were used to characterize the structure of sorbents before and after desulfurization. The results reveal that the microwave sulfidation performs best at 600 °C, while a further increase of the temperature leads to a lower sulfur capacity and utilization rate of Fe 2 O 3 as a result of the pore structure deteriorating sorbents. The Boltzmann function is suitable for describing the H 2 S evolution behavior of the Fe 2 O 3 /AC sorbent bed. Several advantages of microwave sulfidation over the conventional way are as follows: much better performance of Fe 2 O 3 /AC sorbents, less decline in surface area and pore volume per unit sulfur capacity when removing H 2 S at 400, 500, and 600 °C, and more S 2– and oxygen vacancy species on the surface of used desulfurizers. In comparison to conventional desulfurization, there is no notable decrease in the apparent activation energy of the overall sulfidation reaction by the microwave way. The enhancement of the desulfurization rate may be due to quicker ion diffusions and/or better mass transfer under microwave conditions.