Desulfurization of Hot Coal-Derived Fuel Gases with Manganese-Based Regenerable Sorbents. 2. Regeneration and Multicycle Tests

Ben-Slimane, R.; Hepworth, M.T.

doi:10.1021/ef00048a004

Cited by 48 publications

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“…Nanophase transition metal oxide particles are invoked in many actual and potential catalytic processes, e.g., carbon monoxide oxidation, organic synthesis by Fischer−Tropsch reactions, and desulfurization of exhaust gases (36,37). In such processes, the preparation of the catalyst is critical to its function.…”

Section: Discussion: Geochemical and Technological Implicationsmentioning

confidence: 99%

“…In such processes, the preparation of the catalyst is critical to its function. Often such preparation involves a final "activation" step, wherein the catalyst is exposed for a controlled period to a temperature high enough to remove all or most surface water but not high enough to change its morphology and particle size (38,39). The catalyst is then used at lower temperatures.…”

Section: Discussion: Geochemical and Technological Implicationsmentioning

confidence: 99%

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Rapidly reversible redox transformation in nanophase manganese oxides at room temperature triggered by changes in hydration

Birkner

Navrotsky

2014

Proc. Natl. Acad. Sci. U.S.A.

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Chemisorption of water onto anhydrous nanophase manganese oxide surfaces promotes rapidly reversible redox phase changes as confirmed by calorimetry, X-ray diffraction, and titration for manganese average oxidation state. Surface reduction of bixbyite (Mn 2 O 3 ) to hausmannite (Mn 3 O 4 ) occurs in nanoparticles under conditions where no such reactions are seen or expected on grounds of bulk thermodynamics in coarse-grained materials. Additionally, transformation does not occur on nanosurfaces passivated by at least 2% coverage of what is likely an amorphous manganese oxide layer. The transformation is due to thermodynamic control arising from differences in surface energies of the two phases (Mn 2 O 3 and Mn 3 O 4 ) under wet and dry conditions. Such reversible and rapid transformation near room temperature may affect the behavior of manganese oxides in technological applications and in geologic and environmental settings.phase transformation | oxidation/reduction | water adsorption/desorption M anganese oxides are ubiquitous in the natural environment, often occurring as very fine grained (nanopahase) precipitates and coatings, and also find numerous technological applications, especially in catalysis. Easy variation of manganese oxidation state (Mn 2+ , Mn 3+ , Mn 4+ ) lends complexity to phase behavior and physical and chemical properties of manganese oxides. The thermodynamic stability of manganese oxide nanoparticles helps determine the robustness of such oxides and their behavior in soils and larger-scale geochemical cycles, as well as in applications in catalysis, renewable energy, and environmental remediation. The structure and energetics of nanoparticle surfaces are influenced by the phase present and its oxidation state and by the extent of surface hydration; thus dry surfaces are structurally and thermodynamically distinct from hydrated surfaces (1, 2). Using Mn 3 O 4 (hausmannite), Mn 2 O 3 (bixbyite), and MnO 2 (pyrolusite), previously, we showed that the position in temperature−oxygen fugacity space, of oxidation−reduction (redox) phase equilibria, is shifted at the nanoscale due to differences in nanophase surface energy as a function of particle size and surface hydration and that this thermodynamic shift is in favor of the lower surface energy phase (3). In the manganese oxides, the surface energy increases in the order hausmannite, bixbyite, pyrolusite, so small particle size favors the more reduced oxide phase.This paper summarizes observations in the nanoscale Mn 2 O 3 − Mn 3 O 4 system, which is found to undergo rapidly reversible redox phase transformations at room temperature induced by the adsorption/desorption of surface water. It is expected that the degree of reduction is a function of both average particle size and particle size distribution, but this work focuses on only one representative material to provide proof of concept. The rapid response of activated surfaces to changing hydration condition implies thermodynamic control and has implications for geochemistry, planetary scie...

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Section: Discussion: Geochemical and Technological Implicationsmentioning

confidence: 99%

Section: Discussion: Geochemical and Technological Implicationsmentioning

confidence: 99%

Rapidly reversible redox transformation in nanophase manganese oxides at room temperature triggered by changes in hydration

Birkner

Navrotsky

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The fuel gas consists of mainly CO, CO 2 , H 2 , CH 4 , N 2 and H 2 S. This mixture of CO, CH 4 and H 2 produced through gasification is burned after a hot gas cleanup unit and the very hot exhaust is routed through a gas turbine to generate electricity. Afterwards, the residual heat in the exhaust gas is used to boil water for a conventional steam-turbine generator via a heat recovery steam generator thus producing more electricity (Ben- Slimane and Hepworth 1994b).…”

Section: Integrated Gasification Combined Cycle Systemsmentioning

confidence: 99%

“…This completely eliminates the low-temperature liquid-based fuel gas scrubbing systems. Additionally, since the volume of the fuel gas stream is considerably smaller than that of conventional flue gas streams, the removal of H 2 S at high temperature results in considerably lower hardware costs (Ben- Slimane and Hepworth 1994b).…”

Section: Integrated Gasification Combined Cycle Systemsmentioning

confidence: 99%

Cleaner energy production with integrated gasification combined cycle systems and use of metal oxide sorbents for H2S cleanup from coal gas

Atimtay

2001

Clean Products and Processes

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World primary energy demand increases with increases in population and economic development. Within the last 25 years, total energy consumption has almost doubled. In order to meet this demand, research into new sources of energy as well as improving the efficiency of energy production technologies is being carried out. In both cases, the production of clean energy is very important because of environmental concerns and regulations. Integrated gasification combined cycle (IGCC) technology seems to be one of the most promising technologies for production of energy by using fossil fuels, especially coal. Hot gas desulfurization is a crucial issue in the development of the IGCC system. This paper reviews the importance of clean energy production, the IGCC technology and focuses on the development of several metal oxide-based sorbents used for desulfurization of the hot coal gas in the IGCC system.

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“…Among them, we know that wet scrubbing process has gained much more concern due to the SO 2 is easily soluble in water and could be removed completely after scrubbing by absorbent, and manganese oxides (MnO x ) have received special emphasis as a quite effective absorbent for sulfur dioxide recovery recently [11][12][13]. It was known that the SO 2 in the emitted gases reacts with the manganese oxide to forms manganese sulfate, and then treated to regenerate back to the manganese oxide, which is quite effective as an absorbent, but it is uneconomical to regenerate since manganese sulfate is too stable to entirely decompose at temperature about 900°C [18], resulting in relatively high costs. Meanwhile, as the dominant technology in china, and domestic large power plant widely used, the lime/limestone process has been attracting the attention of the world due to its high efficiency and stability [19].…”

Section: Introductionmentioning

confidence: 99%

Resource-Based Method for Realizing Zero Emission of Sulfur Dioxide from Flue Gas

Han¹,

Chen²

2017

Proceedings of the 3rd 2017 International Conference on Sustainable Development (ICSD 2017)

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A resource-based method for completely removal of SO 2 from flue gas by utilizing recycling manganese hydroxide (Mn(OH) 2 ) as an absorbant was proposed, which utilized catalytic oxidation of the manganese in the air on the oxidation of sulfur dioxide to soluble sulfate while removing impurities by filtration to produce high value-added products. Eeffects of reaction temperature and O 2 concentration on sulfite content and effects of PH value and Mn (OH) 2 content on SO 2 removal efficiency were investigated with a bubbling device to obtained the optimal experimental conditions. The method presented 100% removal efficiency with regenerated absorbent, indicating a relatively thorough desulfurization, sulfur dioxide to achieve zero emissions by recycled Mn (OH) 2 in this system. The sulfite content was very low, under 0.027%, compared with manganese sulfate 10%, which show the main component is sulfate ion, reaching to 99.7%, further for the preparation of high quality gypsum products.

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Desulfurization of Hot Coal-Derived Fuel Gases with Manganese-Based Regenerable Sorbents. 2. Regeneration and Multicycle Tests

Cited by 48 publications

References 0 publications

Rapidly reversible redox transformation in nanophase manganese oxides at room temperature triggered by changes in hydration

Rapidly reversible redox transformation in nanophase manganese oxides at room temperature triggered by changes in hydration

Cleaner energy production with integrated gasification combined cycle systems and use of metal oxide sorbents for H2S cleanup from coal gas

Resource-Based Method for Realizing Zero Emission of Sulfur Dioxide from Flue Gas

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