Regenerable Sorbent Pellets for the Removal of Dilute H₂S from Claus Process Tail Gas

Abstract

The Claus process is the most important sour gas sweetening process to recover elemental sulfur from H2S, which is present in raw natural gas and byproduct gases from crude oil refineries. However, current methods for treating the tail gas of the Claus process are expensive and often not environmentally friendly. Various sorbents have been reported for H2S capture, but few reports focus on the pellet design, formation, and testing. In this study, we developed a pelletization method to prepare sorbent pellets with high sulfur capacity and good regenerability for the removal of dilute H2S from Claus process tail gas. The sorbent pellets consisted of mixed metal oxides of Cu, Mg, and Al with fumed silica as the binder and were characterized using various techniques, including X-ray and electron diffraction, N2 sorption, and scanning and transmission electron microscopy. The H2S sorption capacity was evaluated by breakthrough experiments at 150 °C in a gas stream consisting of 100 ppm of H2S in N2. The optimized sorbent pellets gave a stable breakthrough sulfur capacity of ∼5 mmol/g over three cycles of sulfidation and regeneration. They exhibited an average radial crush strength of 154 ± 40 N.

Hydrogen sulphide

“…Additionally, and perhaps significantly, research has shown that the EOR injection of the acid gas mixture has a delayed breakthrough at the producing well compared to a CO₂ EOR injection alone [78]. Furthermore, there can be another case made for the sequestration of these gases especially for H₂S, as the alternative, the desulphurisation process that ends in the reduction of the produced H₂S into sulphur [79] is proving to be financially unfeasible [80] mainly due to a reduced global appetite for elemental sulphur.…”

Effect of Bimetallic-Activated Carbon Impregnation on Adsorption–Desorption Performance for Hydrogen Sulfide (H2S) Capture

“…The modification of mesoporous materials particularly focuses on activated carbon, which is commonly modified through an impregnation process. Several chemicals from basic groups, such as NaOH and KOH [ 32 , 33 ] or transition metal oxides [ 34 , 35 , 36 , 37 ], have been widely used to enhance adsorbent performance. The modified adsorbents show significant results for their H 2 S capture capabilities due to the characteristics of their morphology (i.e., high surface area and micropore or mesopore volume) and, most importantly, due to the surface chemistry, which can promote an adsorption–catalytic oxidation mechanism for H 2 S (resulting in elemental S, SO 2 , sulphates, and sulphuric acid, in addition to metal sulphide) in the presence of even trace amounts of oxygen and high moisture content [ 38 , 39 ].…”

“…The modified adsorbents show significant results for their H 2 S capture capabilities due to the characteristics of their morphology (i.e., high surface area and micropore or mesopore volume) and, most importantly, due to the surface chemistry, which can promote an adsorption–catalytic oxidation mechanism for H 2 S (resulting in elemental S, SO 2 , sulphates, and sulphuric acid, in addition to metal sulphide) in the presence of even trace amounts of oxygen and high moisture content [ 38 , 39 ]. Hence, some recent literature reports suggest that dispersing Zn or Cu oxides onto activated carbon supports can yield effective low-temperature adsorbents capable of simultaneously removing H 2 S and other pollutants from reformate streams [ 36 , 37 ].…”