Nanofibrous carbon with herringbone structure as an effective catalyst of the H2S selective oxidation

Abstract

Granular nanofibrous carbons (NFCs) with herringbone structure were synthesised by the decomposition of natural gas over Ni/Al 2 O 3 catalysts, and their performance in the selective oxidation of hydrogen sulphide was studied. Samples obtained over pure Ni catalysts are the strongest mechanically and easiest to produce. However, they show low selectivity for sulphur and are unstable during operation. Boiling in nitric acid followed by annealing led to improvements in catalytic stability and a significant increase in the selectivity for sulphur in the direct oxidation of hydrogen sulphide. The addition of large amounts of water vapour to the reaction mixture dramatically improved the selectivity and stability of the NFCs.

Catalytic behaviors of combined oxides derived from Mg/AlxFe1−x–Cl layered double hydroxides for H2S selective oxidation

“…Nowadays, the most wellknown technique is the Claus process. 1 However, almost 1% H 2 S is left in the Claus tail gas due to the thermodynamic limitations. [2][3][4] Fortunately, various additional purification processes have been used such as absorption, adsorption and the selective catalytic oxidation technique.…”

Comprehensive study of H2S selective catalytic oxidation on combined oxides derived from Mg/Al-V10O28 layered double hydroxides

“…Today, H 2 S is usually removed by the well-known Claus process [1,2]. However, it is still difficult to reach a permissible level of sulfur emissions due to the thermodynamic limitations of the Claus process and increasingly stringent environmental regulations.…”

Modeling and simulation of an improved ammonia-based desulfurization process for Claus tail gas treatment

“…Currently, the Claus process is one of the most important and widely used technologies to recover elemental sulfur from H 2 S-containing gases. 3,4 Nevertheless, the sulfur recovery efficiency is only 90-96% for two-stage Claus reactors and 95-98% for three stage Claus reactors, [5][6][7][8] due to the thermodynamic limitations of the Claus equilibrium reaction. Thus, there are still 2-3% of sulfur compounds (elemental sulfur vapor, COS, CS 2 , SO 2 and H 2 S) le in Claus tail gas.…”

“…Subsequently, SO 2 is further absorbed by alkaline absorbents and transformed into useful byproducts. Among them, NH 3 based desulfurization process is the most promising one, taking into account that NH 3 can be easily obtained in coal chemical industries. However, in the case of traditional ammonia-based desulfurization process, a tail gas cooling system is required to cool the fuel gas, which wastes a lot of water and energy.…”