Microwave effects on the structure of CeO2-doped zinc oxide sorbents for H2S removal

Wu, Mengmeng; Hu, Chengcheng; Feng, Yu; Fan, Huiling; Mi, Jie

doi:10.1016/j.fuel.2014.12.090

Cited by 32 publications

(27 citation statements)

References 14 publications

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“…Sulfur capacity (SC, %) was the ratio of the mass (unit: g) of adsorbed sulfur per 100 g of sorbent. The formula for calculating SC is described elsewhere. , The utilization rate of ZnO (UR, %) is the ratio of experimental SC to the theoretical SC …”

Section: Experimental Sectionmentioning

confidence: 99%

“…It can reduce the concentration of H 2 S from several thousand ppm to sub ppm levels . Zinc oxide is most widely used at midtemperatures (350–400 °C). , A higher desulfurization temperature can result in unfavorable thermodynamics but a larger reaction rate. − However, ZnO can easily be reduced to elemental Zn under the strong reducing atmosphere at high temperatures (>600 °C) . The ZnO could be stabilized by addition of TiO 2 resulting from the formation of Zn 2 TiO 4 with a spinel structure, while the activity reduction of the sorbents is irresistible. , According to Novem’s study, the optimum sulfidation temperature during the IGCC (integrated gasification combined cycle) process ranges from 350 to 550 °C due to lower overall process cost.…”

Section: Introductionmentioning

confidence: 99%

“…6 Zinc oxide is most widely used at midtemperatures (350−400 °C). 7,8 A higher desulfurization temperature can result in unfavorable thermodynamics but a larger reaction rate. 6−8 However, ZnO can easily be reduced to elemental Zn under the strong reducing atmosphere at high temperatures (>600 °C).…”

Section: Introductionmentioning

confidence: 99%

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

Jia

Fan

et al. 2017

Energy Fuels

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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).

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Section: Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Jia

Fan

et al. 2017

Energy Fuels

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Section: Introductionmentioning

confidence: 99%

“…In comparison with traditional preparation methods, microwave irradiation is a burgeoning method to prepare desulfurizer by virtue of it can provide a rapid drying and evenly heating [21]. The advantages of microwave heating over conventional heating have been studied in our previous work [22].But under the condition of high temperature, the ZnO sorbents would evaporate thus limit its development [7,23]. Moreover, single ZnO sorbents show many disadvantages such as decrease of sorbent efficiency and degradation of the mechanical properties [24].…”

mentioning

confidence: 99%

The Effects of CeO2 Addition on the Performance of Zinc Oxide Sorbent Prepared by Microwave Solid-State Method for H2S Removal

Su¹,

Wu²,

Li³

et al. 2015

Proceedings of the 2015 International Symposium on Energy Science and Chemical Engineering

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Abstract. ZnO sorbents with different CeO 2 loadings were prepared by microwave calcination and tested the performance for H 2 S removal in a fixed-bed reactor at 500 . The results r ℃ evealed that the Ce-doped sorbents have a higher efficiency and longer breakthrough time compared with non-modified sorbents. The optimal sulfur capacity (13.03 gS/100 g) and breakthrough time (17.5 h) were obtained when the content of CeO 2 up to 4 wt.%. XRD, SEM, XPS and mercury porosimetry methods were used to characterize the structure of sorbents. Analysis data indicated that the addition of CeO 2 leads to better pore structure and larger specific surface, which facilitates the diffusion of H 2 S into the active sites. Furthermore, the presence of CeO 2 also results in an increase in the content of surface elements including Zn and O, which contributes to improve the ability of H 2 S removal. IntroductionThe integrated coal gasification combined cycle (IGCC) process is considered as one of the promising clean coal technologies in the 21st century [1][2][3], meanwhile the high temperature gas desulfurization (HTGD) was regarded as one of the key techniques in the IGCC system [2][3][4][5][6][7]. The oxides of Zn, Fe, Ca, Mn and Co as H 2 S sorbents for HTGD are investigated extensively nowadays [7][8][9][10][11][12][13].Among these sorbents, Zinc oxide sorbents are considered to be the most promising material for HTGD because of its large sulfur capacity and excellent desulfurization thermodynamics [7,14,15]. Up to now, many synthesis methods have been investigated [16][17][18][19][20]. In comparison with traditional preparation methods, microwave irradiation is a burgeoning method to prepare desulfurizer by virtue of it can provide a rapid drying and evenly heating [21]. The advantages of microwave heating over conventional heating have been studied in our previous work [22].But under the condition of high temperature, the ZnO sorbents would evaporate thus limit its development [7,23]. Moreover, single ZnO sorbents show many disadvantages such as decrease of sorbent efficiency and degradation of the mechanical properties [24]. In order to improve the performance, ZnO sorbents mixed with many metal oxides have been evaluated [24][25][26][27]. CeO 2 as one of the most promising rare earths has an outstanding oxygen storage capacity and improve the performance of ZnO sorbents for desulfurization [11,[28][29][30].In this paper, the performance of ZnO based sorbents doped with various content of CeO 2 employed for high temperature coal gas desulfurization were studied. Also, the effects of the amount of CeO 2 loaded to the sorbents on the performance for H 2 S removal were studied. The analysis data of structure and textural properties were provided by XRD, XPS, SEM and mercury porosimetry.

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Effect of preparation method of active component on the cycling performance of sorbents for hot coal gas clean‐up

Feng

Shi

et al. 2017

Can J Chem Eng

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High temperature gas desulphurization is an efficient environmentally friendly process for high efficiency technologies with syngas clean‐up. The present study investigated the impact of preparation methods on the behaviours of ZnO/red clay sorbent. The sorbents were prepared by the homogeneous precipitation method and solid‐state method, respectively. The surface and structural properties of the sorbents were characterized by thermogravimetric, X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscope‐elemental mapping, and N2 adsorption analysis. Successive desulphurization‐regeneration cycles were conducted to investigate the reusability of the sorbents. After four cycles of desulphurization‐regeneration experiments, the breakthrough times of the two kinds of regenerated sorbents plunged 18.17 % and 23.26 %, respectively. Attritions of sorbents have not been observed, meaning the regenerated sorbents still maintain a high mechanical strength. The sorbents prepared through the homogeneous precipitation method were found to exhibit a longer breakthrough time much greater than those prepared by the solid‐state method. The characterization data indicate that the homogeneous precipitation method results in more uniform distribution of active component sorbent with smaller particle size and better pore structure, which favours the chemical reaction and mass transfer processes.

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Microwave effects on the structure of CeO2-doped zinc oxide sorbents for H2S removal

Cited by 32 publications

References 14 publications

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

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

The Effects of CeO2 Addition on the Performance of Zinc Oxide Sorbent Prepared by Microwave Solid-State Method for H2S Removal

Effect of preparation method of active component on the cycling performance of sorbents for hot coal gas clean‐up

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