Direct catalytic decomposition of nitric oxide. Final report

Flytzani‐Stephanopoulos, Maria; Sarofim, A.F.; Zhang, Yanping

doi:10.2172/111932

Cited by 4 publications

(8 citation statements)

References 4 publications

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“…More recently, zinc oxide has also been investigated as a regenerable sorbent. [39][40][41][42][43][44][45][46] The thermodynamic equilibrium for sulfidation of ZnO is quite favorable, yielding desulfurization down to a few ppm H 2 S. The sulfidation kinetics of ZnO, however, are slower 47 compared to those of pure iron oxide, and the regenerability of ZnO is restricted above 700 °C by the loss of surface area and the formation of zinc sulfate at low regeneration temperatures.…”

Section: Sorbent Developmentmentioning

confidence: 99%

“…[43][44][45][48][49][50][51][52][53][54] A compound of zinc and iron oxides, zinc ferrite, ZnFe 2 O 4 , developed by DOE/METC was tested at the pilot stage for desulfurization of low-Btu gases. [55][56][57] Physical durability of the zinc ferrite sorbent in long-term testing precluded further use at that time, but recent work suggests that improved performance can be obtained with new preparation techniques.…”

Section: Sorbent Developmentmentioning

confidence: 99%

“…58 Because of the apparent limitations of the zinc ferrite sorbent, many investigators have been conducting research to develop a superior mixed metal oxide sorbent. [42][43][44][45][59][60][61][62][63] Earlier experimental studies that pioneered the use of mixed-metal oxides were performed at the Massachusetts Institute of Technology (MIT), [64][65][66] Research Triangle Institute (RTI), 67 68 Electrochem, 69 44,45 has shown that titanium oxide is a better alternative to iron oxide additives in terms of the higher stability of the titanates over the ferrite compounds of zinc, and their similar sulfidation equilibria. With zinc titanates, the sulfidation temperature has been shown to extend to 700 °C, and sintering of the ZnO was greatly reduced.…”

Section: Sorbent Developmentmentioning

confidence: 99%

See 2 more Smart Citations

Advanced Sorbent Development Program; Development of Sorbents for Moving-Bed and Fluidized-Bed Applications

AYALA¹,

VENKATARAMANI²

1998

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The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 °C (900-1000 °F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 °C (650 °F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes.The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 °C (650-1000 °F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a cost assessment and a market plan for large-scale fabrication of sorbents were developed. As an optional task, long-term bench-scale tests of the best moving-bed sorbents were conducted.Starting from thermodynamic calculations, several metal oxides were identified for potential use as hot gas cleanup sorbents using constructed phase stability diagrams and laboratory screening of various mixed-metal oxide formulations. Modified zinc titanates and other proprietary metal oxide formulations were evaluated at the bench scale and many of them found to be acceptable for operation in the target desulfurization temperature range of 370 °C (700 °F) to 538 °C (1000 °F) and regeneration temperatures up to 760 °C (1400 °F). Further work is still needed to reduce the batch-to-batch repeatability in the fabrication of modified zinc titanates for larger scale applications.The information presented in this Volume 1 report contains the results of moving-bed sorbent development at General Electric's Corporate Research and Development (GE-CRD). A separate Volume 2 report con...

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Section: Sorbent Developmentmentioning

confidence: 99%

Section: Sorbent Developmentmentioning

confidence: 99%

Section: Sorbent Developmentmentioning

confidence: 99%

See 1 more Smart Citation

Advanced Sorbent Development Program; Development of Sorbents for Moving-Bed and Fluidized-Bed Applications

AYALA¹,

VENKATARAMANI²

1998

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“…More recently, zinc oxide has also been investigated as a regenerable sorbent. [4][5][6][7][8] The thermodynamic equilibrium for sulfidation of ZnO is quite favorable, yielding desulfurization down to a few ppmv H 2 S. The sulfidation kinetics of ZnO, however, is slower 9 compared to that of iron oxide, and the regenerability of ZnO is restricted by the loss of surface area at high temperatures and the formation of zinc sulfate at low regeneration temperatures.…”

mentioning

confidence: 99%

“…[6][7][8][10][11][12][13][14][15][16] A compound of zinc and iron oxides, zinc ferrite, ZnFe 2 O 4 , developed by DOE/FETC has reached pilot-stage (testing) for desulfurization of low-Btu gases. [17][18][19] However, physical durability of the zinc ferrite sorbent in long-term testing appears to be inadequate for IGCC application.…”

mentioning

confidence: 99%

Advanced Sorbent Development Program

UNKNOWN¹

1998

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The overall objective of this program was to develop regenerable sorbents for use in the temperature range of 343 o to 538 o C (650 o to 1000 o F) to remove hydrogen sulfide (H 2 S) from coal-derived fuel gases in a fluidized-bed reactor.The goal was to develop sorbents that are capable of reducing the H 2 S level in the fuel gas to less than 20 ppmv in the specified temperature range and pressures in the range of 1 to 20 atmospheres, with chemical characteristics that permit cyclic regeneration over many cycles without a drastic loss of activity, as well as physical characteristics that are compatible with the fluidized bed application. Background Information

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Process Intensification by Membrane Reactors: High‐Temperature Water Gas Shift Reaction as Single Stage for Syngas Upgrading

Brunetti¹,

Caravella²,

Drioli³

et al. 2012

Chem Eng & Technol

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Pd-based membrane reactors (MRs) selectively removing hydrogen shift the equilibrium conversion of this new reactor type to values higher than those imposed by thermodynamics to traditional reactors. Thus, the equilibrium conversion of CO is significantly increased and can be very strongly depending on the hydrogen extracted also at a higher temperature. This property of the MRs offers important benefits also in terms of process intensification. In the typical high-temperature range for this reaction, i.e., 300-450°C, the performance of an MR turned out to be so effective that the two reactors of a traditional process can be replaced by one MR of lower volume, too. The conversion of the MR is higher than the one of the whole traditional process which includes a heat exchanger in addition to two reactors. Consequently, less and smaller unit operations are required when an MR operates the water gas shift reaction pursuing the process intensification philosophy.

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Direct catalytic decomposition of nitric oxide. Final report

Cited by 4 publications

References 4 publications

Advanced Sorbent Development Program; Development of Sorbents for Moving-Bed and Fluidized-Bed Applications

Advanced Sorbent Development Program; Development of Sorbents for Moving-Bed and Fluidized-Bed Applications

Advanced Sorbent Development Program

Process Intensification by Membrane Reactors: High‐Temperature Water Gas Shift Reaction as Single Stage for Syngas Upgrading

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