Direct catalytic decomposition of nitric oxide. Quarterly technical progress report No. 10, January--March 1994
This project investigates a suitable catalyst system for the direct nitric oxide decomposition in post-combustion gas streams. This process does not use a reductant, such as the ammonia used in the Selective Catalytic Reduction (SCR) of NO{sub x} to nitrogen. Therefore, it is a greatly simplified process basically involving passing the flue gas through a catalytic converter. Catalysts are prepared by incorporating metal cations into zeolite supports according to ion exchange procedures widely used in preparation of metal/zeolite catalysts. Particular emphasis is given in this work on promoted Cu-exchanged zeolites, especially the catalyst systems Mg/Cu-ZSM-5 and Ce/Cu-ZSM-5, which are promising for NO conversion to nitrogen at typical flue gas O{sub 2} and NO levels and over the temperature range of 673--873{degrees}C. The effect of zeolite modification, copper exchange level and catalyst preparation conditions on the catalytic activity are studied in O{sub 2}-free, O{sub 2}-rich gases, as well as wet (2--20% H{sub 2}O) gas streams in a packed-bed microreactor. Characterization of catalysts is performed by XRD, STEM, TEM and ESR. During this quarter it was found that severe steaming (20% H{sub 2}O) of Na-ZSM-5 at temperatures above 600{degrees}C caused partial vitreous glass formation and dealumination. Unpromoted Cu-ZSM-5 catalysts suffer drastic loss of NO decomposition activity in wet gas streams at 500{degrees}C. Activity is partially recovered in dry gas. Copper migration out of the zeolite channels leading to CuO formation has been identified by STEM/EDX. In Ce/Cu-ZSM-5 catalysts the wet gas activity i`s greatly improved. CuO particle formation is less extensive and the dry gas activity is largely recovered upon removal of the water vapor.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-91PC91293
- OSTI ID:
- 10154180
- Report Number(s):
- DOE/PC/91293-10; CONF-940301-34; ON: DE94012616; BR: AA1525050
- Resource Relation:
- Conference: 207. spring national meeting of the American Chemical Society (ACS),San Diego, CA (United States),13-18 Mar 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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Direct catalytic decomposition of nitric oxide. Quarterly technical progress report number 12, July--September, 1994
Direct catalytic decomposition of nitric oxide. Final report
Related Subjects
FOSSIL-FUEL POWER PLANTS
AIR POLLUTION CONTROL
NITROGEN OXIDES
NITRIC OXIDE
REDUCTION
DECOMPOSITION
CATALYSTS
COPPER
CATALYTIC EFFECTS
ZEOLITES
CATALYST SUPPORTS
PROGRESS REPORT
MAGNESIUM
CERIUM
X-RAY DIFFRACTION
ELECTRON MICROSCOPY
ELECTRON SPIN RESONANCE
WATER VAPOR
200202
NOXIOUS GAS AND PARTICULATE EMISSIONS