Fe-Based Sorbent for Hot Coal Gas under Microwave Irradiation: Desulfurization Performance and Microwave Effects

Abstract

The microwave-assisted chemical process is environmentally friendly and energy-saving. In this study, microwave irradiation was applied to enhance the hot coal gas desulfurization process with modified semi-coke-supported Fe 2 O 3 as the sorbent. The results indicate that the sorbent with 20% Fe 2 O 3 shows the greatest breakthrough sulfur capacity (9.0%) at 500 °C in the simulated coal gas. Besides Fe 1−x S, sulfur was also produced during the desulfurization process. The deactivation model could be used to simulate the adsorption behavior of the sorbents for H 2 S. The activation energies of the sulfidation reaction by microwave and conventional techniques are 26.9 and 27.8 kJ mol −1 , respectively. The sorbents adsorbing H 2 S under microwave irradiation show much larger initial rate constants (308−2071 m 3 min −1 kg −1 ) for the sulfidation reaction. In comparison to the conventional technique, microwave desulfurization generally results in much better performance of H 2 S removal and leads to less negative effects on the pore structure of the sorbent. The improvement of desulfurization properties may be attributed to the roles of microwave irradiation (enhanced mass transfer kinetics and intensified ion diffusions). Additionally, the adverse influence of H 2 , CO, and CO 2 on the sulfur capacity of the sorbents under microwave irradiation is not significant when the adsorption time varies from 0 to 120 min.

Catalytic Conversion of Coal and Biomass Volatiles: A Review

“…With differences in catalytic decomposition of NH 3 , sulfur removal in gasification is usually conducted with the help of sorbent that is efficient to absorb H 2 S. Metal oxides are frequently used as the sorbent because of their reactiveness with sulfur contaminants (eq ). Fe − and Zn − based sorbents are the most popular catalysts to react with H 2 S. When they were used individually, some problems appeared, such as the reduction of metal oxides under H 2 and the regeneration of spent catalysts. Hence, the combination of different metals, such as Mn and Ti, ,− can promote the adsorption efficiency and wipe out the drawbacks.…”

Structure Characteristics and Hot-Coal-Gas Desulfurization Properties of Zn-Based Sorbents Supported on Mesoporous Silica with Different Pore-Arrangement Patterns: A Comparison Study

“…Pore Structures of Two Supports. Hot coal gas desulfurization 19,20 in this study occurs at middle and high temperatures (400−700 °C). The structural (especially the pore structure) stability of MCM-41 and MCM-48 at elevated temperatures is an important factor influencing the gas diffusion and mass transfer.…”

Rotten Eggs Revaluated: Ionic Liquids and Deep Eutectic Solvents for Removal and Utilization of Hydrogen Sulfide

“…This is because high temperatures are undesirable for the exothermic sulfurization reaction, even if kinetically beneficial. 46 The commercialization of Fe 2 O 3 for H 2 S removal is limited due to their low specific surface area and small pore-volume, as well as the pores getting blocked during the adsorption. As a result, Fe 2 O 3 is commonly combined with other materials, such as mesostructured silica supports (M41S), 47 semicoke, 46 oxygenated porous carbon (OPC), 48 red clay, 49 and so on, to increase the stability of Fe 2 O 3 and the desulfurization performance.…”

“…46 The commercialization of Fe 2 O 3 for H 2 S removal is limited due to their low specific surface area and small pore-volume, as well as the pores getting blocked during the adsorption. As a result, Fe 2 O 3 is commonly combined with other materials, such as mesostructured silica supports (M41S), 47 semicoke, 46 oxygenated porous carbon (OPC), 48 red clay, 49 and so on, to increase the stability of Fe 2 O 3 and the desulfurization performance. Zinc oxide (ZnO), as a commonly used desulfurizer, has good thermal stability and strong desulfurization ability.…”