Hot Coal Gas Desulfurization Using Regenerable ZnO/MCM41 Prepared via One-Step Hydrothermal Synthesis

Abstract

ZnO/MCM41 sorbents with bimodal pore structure were prepared via one-step hydrothermal synthesis. The structure of fresh, sulfided, and regenerated sorbents was characterized using XRD, TEM, SEM, nitrogen adsorption isotherms, and XPS techniques. The results indicate that the desulfurizer with 35% ZnO shows the highest sulfur capacity (11.0 g of S/100 g of sorbents). The optimum regeneration conditions were 650 °C, 3000 h −1 , and 6% O 2 concentration. Both ZnO and ZnSiO 4 were observed in the regenerated sorbents. The increase of regeneration cycles leads to higher content of the Zn 2 SiO 4 . However, it results in no significant effect on the performance of sorbents during five sulfidation/regeneration cycles. It may be due to the transformation of Zn 2 SiO 4 into ZnO under conditions of desulfurization. After five successive sulfidation/regeneration cycles, the sorbents still maintain high sulfur capacity (9.8 g of S/100 g of sorbents) and mechanical strength (80 N/cm).

Sub-Micrometric MCM-41 Particles as Support to Design Efficient and Regenerable Maghemite-Based Sorbent for H2S Removal

“…18 Concerning this latter application, H 2 S removal from natural gas and sour syngas is of particular interest considering the large amounts produced and the harmful effects on the environment, and damages on pipes and turbines caused by corrosion phenomena in industrial plants. [19][20][21] Among the several metal oxide-based candidates, although ZnO shows the most favorable thermodynamics, its main disadvantages such as the high regenerate temperature (at about 650 C, depending on particle dimension and atmosphere composition), 19 21 22 and the moderate sulfur removal * Author to whom correspondence should be addressed. capacity per mass unit, 22 27 render other oxides 20 23 24 like maghemite appealing substitutes.…”

Removal of Hydrogen Sulfide from Gas Streams Using Porous Materials: A Review

“…The large mesopores and high surface area allow high dispersion of the metal oxides into the mesoporous silica frameworks, preventing the agglomeration or sintering of particles under exposure to high temperatures. The metal oxide can be loaded into mesoporous silica matrix either during its synthesis (direct synthesis) 82 or by postsynthesis (two steps approach) 83 in which the mesoporous silica matrix is first synthesized and then the desired metal oxide is loaded to the structure through different methods. The latter is often preferred since it is difficult to maintain the ordered mesoporous structure by simultaneous condensation of two phases.…”

“…Improved H 2 S desulfurization activity of ZnO/ mesoporous silica nanocomposites prepared through various strategies has been demonstrated in different studies. Wu et al 82 synthesized ZnO supported mesoporous silica MCM41 with bimodal pore structure via a one-step hydrothermal approach and observed high sulfur capacity up to 110 mg g −1 at 35% ZnO loading. In the preparation method, the zinc source was inserted already during the synthesis of MCM-41.…”

Removal of hydrogen sulfide gas using coal fly ash – blast furnace cement composite

“…In a previous study on the removal of H 2 S gas, porous metal oxides such as Fe 2 O 3 /Al 2 O 3 (Su et al 2017), Co 3 O 4 (Wang et al 2017a), three-dimensionally ordered macropore CuO (Wang et al 2017b), ZnO (Tran 2016), and zeolite (Liu & Wang 2017;Yang et al 2018), metal oxide-loaded mesoporous silicas (Montes et al 2013;Wu et al 2017;Cara et al 2018), and Fenton reagent (Wang et al 2019) were proposed. However, these adsorbents require significant preparation costs.…”