High-Capacity Regenerable H₂S Sorbent for Reducing Sulfur Emissions

Abstract

The separation of H2S from natural gas, biogas, and coal gas is an essential process that requires large energy input and high capital costs. We propose a new sorption-based process, which can be coupled with the Claus desulfurization process to reduce sulfur emissions. This new process is based on a new sorbent material consisting of a specific composition of Cu, Mg, and Al oxides and exhibiting superior sulfur capacity (∼7.5 mmol/g) at process conditions compatible for integration with the Claus process. CuO is the active sorbent component, which during H2S uptake is converted to CuS and can be fully regenerated during cyclic operation. Al2O3 and small amounts of MgO are shown to be essential components that contribute to sorbent activity and stability.

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

“…However, very little research has focused on the pelletization process for practical application of the materials. As an example of a metal-oxide-based sorbent, we have demonstrated that a mixed metal oxide (MMO) consisting of CuO, MgO, and Al 2 O 3 shows high sulfur capacity (∼7.5 mmol/g) and stability on the laboratory-scale for capturing H 2 S at 100 and 1435 ppm levels . Moreover, the proposed sorption–regeneration process of the sorbent is compatible with integration in the Claus process by redirecting SO 2 formed during regeneration back to the Claus furnace; it can, therefore, achieve both effective sulfur capture and recovery (2H 2 S + SO 2 → 3S + 2H 2 O).…”

“…As an example of a metal-oxidebased sorbent, we have demonstrated that a mixed metal oxide (MMO) consisting of CuO, MgO, and Al 2 O 3 shows high sulfur capacity (∼7.5 mmol/g) and stability on the laboratoryscale for capturing H 2 S at 100 and 1435 ppm levels. 29 Moreover, the proposed sorption−regeneration process of the sorbent is compatible with integration in the Claus process by redirecting SO 2 formed during regeneration back to the Claus furnace; it can, therefore, achieve both effective sulfur capture and recovery (2H 2 S + SO 2 → 3S + 2H 2 O). The preparation of the MMO involves the coprecipitation of Cu, Mg, and Al nitrate solutions with Na 2 CO 3 solution and a calcination step, which yields the final product as a fine powder that is highly porous due to textural porosity.…”

Improving catalytic performance via induction heating: selective oxidation of H2S on a nitrogen-doped carbon catalyst as a model reaction

“…Hydrogen sulfide (H2S), one of the major toxic and malodorous gases, is commonly emitted from chemical industries, such as natural gas refineries, crude oil, biogas purification and coal chemistry. H2S is not only harmful to the human, but also induces corrosion to the facilities and pipeline as well as downstream catalyst poisoning [14][15][16]. The most widely method for removing H2S is the equilibrated Claus process (2 H2S + 3 O2 → 2 SO2 + 2 H2O and 4 H2S + 2 SO2 → 3 S2 + 4 H2O).…”

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 ].…”