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Title: Direct catalytic decomposition of nitric oxide

Abstract

This project investigates a suitable catalyst system for direct NO decomposition in post-combustion NO[sub x] control. Since the process does not use a reductant, 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 by ion exchange. Catalysts of primary interest include Cu, Pd, Ag, and Ni exchanged zeolites. Particular emphasis is given on promoted Cu-exchanged zeolites, especially the catalyst system Mg/Cu-ZSM-5 and a few others, which are promising for NO conversion to nitrogen at typical flue gas O[sub 2] and NO levels and over the temperature range of 723--873K. Effects of zeolite modification, Cu exchange level and catalyst preparation conditions on the catalyst activity are studied in a packed-bed microreactor. Temperature-programmed desorption and reduction experiments will be carried out in a thermogravimetric analyzer and a single-particle electrodynamic balance. Kinetic studies of NO and O[sub 2] interaction with catalysts over a wide temperature range as well as catalyst structural investigations are planned.

Authors:
; ;
Publication Date:
Research Org.:
Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering
Sponsoring Org.:
DOE; USDOE, Washington, DC (United States)
OSTI Identifier:
6788311
Alternate Identifier(s):
OSTI ID: 6788311; Legacy ID: DE93008107
Report Number(s):
DOE/PC/91293-T1
ON: DE93008107
DOE Contract Number:
FG22-91PC91293
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 33 ADVANCED PROPULSION SYSTEMS; CATALYSTS; CHEMICAL PREPARATION; NITRIC OXIDE; DECOMPOSITION; NITROGEN DIOXIDE; AIR POLLUTION CONTROL; CATALYTIC CONVERTERS; COPPER IONS; ION EXCHANGE; MAGNESIUM IONS; PROGRESS REPORT; PROMOTERS; ZEOLITES; CHALCOGENIDES; CHARGED PARTICLES; CHEMICAL REACTIONS; CONTROL; DOCUMENT TYPES; EQUIPMENT; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; IONS; MATERIALS; MINERALS; NITROGEN COMPOUNDS; NITROGEN OXIDES; OXIDES; OXYGEN COMPOUNDS; POLLUTION CONTROL; POLLUTION CONTROL EQUIPMENT; SILICATE MINERALS; SYNTHESIS 540120* -- Environment, Atmospheric-- Chemicals Monitoring & Transport-- (1990-); 330701 -- Emission Control-- Nitrogen Oxides

Citation Formats

Flytzani-Stephanopoulos, M., Sarofim, A.F., and Zhang, Y. Direct catalytic decomposition of nitric oxide. United States: N. p., 1992. Web. doi:10.2172/6788311.
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Flytzani-Stephanopoulos, M., Sarofim, A.F., & Zhang, Y. Direct catalytic decomposition of nitric oxide. United States. doi:10.2172/6788311.
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Flytzani-Stephanopoulos, M., Sarofim, A.F., and Zhang, Y. Wed . "Direct catalytic decomposition of nitric oxide". United States. doi:10.2172/6788311. https://www.osti.gov/servlets/purl/6788311.
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@article{osti_6788311,
title = {Direct catalytic decomposition of nitric oxide},
author = {Flytzani-Stephanopoulos, M. and Sarofim, A.F. and Zhang, Y.},
abstractNote = {This project investigates a suitable catalyst system for direct NO decomposition in post-combustion NO[sub x] control. Since the process does not use a reductant, 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 by ion exchange. Catalysts of primary interest include Cu, Pd, Ag, and Ni exchanged zeolites. Particular emphasis is given on promoted Cu-exchanged zeolites, especially the catalyst system Mg/Cu-ZSM-5 and a few others, which are promising for NO conversion to nitrogen at typical flue gas O[sub 2] and NO levels and over the temperature range of 723--873K. Effects of zeolite modification, Cu exchange level and catalyst preparation conditions on the catalyst activity are studied in a packed-bed microreactor. Temperature-programmed desorption and reduction experiments will be carried out in a thermogravimetric analyzer and a single-particle electrodynamic balance. Kinetic studies of NO and O[sub 2] interaction with catalysts over a wide temperature range as well as catalyst structural investigations are planned.},
doi = {10.2172/6788311},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1992},
month = {Wed Jan 01 00:00:00 EST 1992}
}
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Technical Report:
View Technical Report (0.65 MB)
DOI:  10.2172/6788311
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  • ; ;
    This project investigates a suitable catalyst system for the direct NO decomposition in post-combustion gas streams. The process does not use a reductant, such as the ammonia used in 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. The catalysts of primary interest include copper, palladium, silver, and nickel exchanged ZSM-5 catalysts. Particular emphasis is given in this work on promotedmore » Cu-exchanged zeolites, especially the catalyst system Mg/Cu-ZSM-5 and a few others, which are promising for NO conversion to nitrogen at typical flue gas O[sub 2] and NO levels and over the temperature range of 723--873K. Effects of zeolite modification, copper exchange level and catalyst preparation conditions on the catalyst activity are studied in a packed-bed microreactor. Temperature-programmed desorption (TPD) and reduction (TPR) experiments will be carried out in a thermogravimetric analyzer and a single-particle electrodynamic balance (EDB). Kinetic studies of NO and O[sub 2] interaction with catalysts over a wide temperature range as well as catalyst structural investigations are planned.« less

  • ; ;
    This project investigates a suitable catalyst system for direct NO decomposition in post-combustion gas streams. This process does not use a reductant, such as the ammonia used in Selective Catalytic Reduction (SCR) of NO{sub x} to nitrogen. Therefore, it is a greatly simplified process 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. The catalysts of primary interest are copper, cerium, palladium, silver, and nickel exchanged ZSM-5 catalysts. Particular emphasis is given in this work on promoted Cu-ZSM-5more » zeolites, especially the catalyst system Mg/Cu-ZSM-5, Ce/Cu-ZSM-5 and a few others, which are promising for NO conversion to nitrogen at typical flue gas 0{sub 2} and NO levels and over the temperature range of 723--873K. The effect of zeolite modification, copper exchange level and catalyst preparation conditions on the catalyst activity are studied in a packed-bed microreactor. Kinetic studies of NO and 0{sub 2} interaction with catalysts over a wide temperature range as well as catalyst structural investigations by STEM/EDX, XRD, and XPS are aimed at elucidating the role of cocation on the copper ion activity and stability in dry and wet reaction mixtures. During this quarter, the atomic ratios of copper, cerium, oxygen, and silicon on the surface of fresh, and used Cu-ZSM-5 and Ce/Cu-ZSM-5 catalysts were measured by x-ray-excited photoelectron spectroscopy (XPS). Dynamic change of copper with treatment of the samples was identified. Enrichment of copper was found in hydrated and steamed samples, while copper migrated into zeolite channels after the samples were heated in dry gas streams. Cerium was highly concentrated on the zeolite surface regions, and was much less mobile than copper.« less

  • ; ; ; ...
    This project will investigate a suitable catalyst system for the direct NO decomposition, for post-combustion NO{sub x} control. The proposed process will not use a reductant, such as ammonia in case of Selective Catalytic Reduction (SCR) process for catalytic reduction of NO{sub x} to nitrogen. This is a simplified process basically involving passing the flue gas through a catalytic converter, thus avoiding problems generally associated with the commercial Selective Catalytic Reduction (SCR) process, namely high operating cost, ammonia slip, and potential N{sub 2}O emissions. A brief description of the proposed work is as follows: catalysts will be prepared by incorporatingmore » metal cations into zeolite supports according to ion exchange procedures widely used in preparation of metal/zeolite catalysts. Zeolites will be modified to improve catalytic activity, by blocking ion exchange sites in the small pores of zeolites with promoter cations of high valence. The catalysts of primary interest include copper (Cu), palladium (Pt), silver (Ag), and nickel (Ni) exchanged zeolites. Additional tests will be conducted for the promoter/Cu-exchanged zeolites, particularly the catalyst system Mg/Cu-ZSM-5 for NO conversion to nitrogen at typical flue gas O{sub 2} and NO levels and over the temperature range of 723-873K. Effects of zeolite modification, copper exchange level and catalyst preparation conditions on the catalyst activity will be studied in a packed-bed microreactor. Temperature-programmed desorption (TPD) and reduction (TPR) experiments will be carried out in a thermogravimetric analyzer and a single-particle electrodynamic balance (EDB). Kinetic studies of NO and O{sub 2} interactions with catalysts as well as catalyst structural investigations are planned. These would provide new ways for improving the decomposition in oxygen-containing exhaust gas stream.« less

  • ; ;
    This project investigated a suitable catalyst system for the direct NO decomposition for post-combustion NO{sub x} control. The studied process does not use a reductant, such as ammonia in the case of Selective Catalytic Reduction (SCR) process for catalytic reduction of NO{sub x} to nitrogen. This is a simplified process basically involving passing the flue gas through a catalytic converter, thus avoiding problems generally associated with the commercial SCR process, namely high operating cost, ammonia slip, and potential N{sub 2}O emissions. The main results from this research project are summarized in the following: Cu-ZSM-5 and M/Cu-ZSM-5 were synthesized by incorporatingmore » metal cations into ZSM-5 zeolite supports by optimized ion exchange procedures. It was found that (1) the catalytic activity of Cu-ZSM-5 only increased with copper loading when the Cu-ZSM-5 was prepared in an aqueous copper acetate solution with pH lower than 5.74; (2) high pH of the solution led not only to ion-exchanged Cu{sup 2+}, but also copper deposition on the zeolite surface forming inactive CuO particles as identified by STEM/EDX and XRD; (3) the sequence of metal ion exchange first, followed by copper ion exchange to synthesize M/Cu-ZSM-5, where M represents any metal ion but copper, was important for the cocation to show promotion effects; and (4) air-calcination of M-ZSM was effective in keeping M cations in the zeolite during subsequent copper ion exchange. Positive alkaline and rare earth metal cocation effects on the Cu-ZSM-5 were identified in oxygen-containing gas mixtures in the high temperature region (450--600C). Cerium ion promoted the Cu-ZSM-5 activity in the low temperature range (< 450C) in oxygen-free gas mixture, while alkaline earth and transition metal cocations improved the NO conversion to N{sub 2} in high temperature region.« less

  • ; ; ; ...
    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. A systematic study of water vapor effects on the structure and Cu{sup 2+} ion exchange capacity of parent ZSM-5 zeolites and on the catalytic activity of the Cu-ZSM-5 and metal ion (mg{sup 2+} and Ce{sup 3+}) modified Cu-ZSM-5 catalysts for NO decomposition hasmore » been performed during this quarter. Mg{sup 2+} and Ce{sup 3+} cocations in copper ion-exchanged ZSM-5 zeolites display a positive effect on the decomposition of nitric oxide to nitrogen and oxygen. The catalytic activity of a Cu-ZSM-5 catalyst was examined after it was exposed to different inert and oxygen-containing gas streams. The results show that the steady-state catalyst activity is not sensitive to three treatments.« less