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Title: Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx

Abstract

Nanocrystalline zeolites with discrete crystal sizes of less than 100 nm have different properties relative to zeolites with larger crystal sizes. Nanocrystalline zeolites have improved mass transfer properties and very large internal and external surface areas that can be exploited for many different applications. The additional external surface active sites and the improved mass transfer properties of nanocrystalline zeolites offer significant advantages for selective catalytic reduction (SCR) catalysis with ammonia as a reductant in coal-fired power plants relative to current zeolite based SCR catalysts. Nanocrystalline NaY was synthesized with a crystal size of 15-20 nm and was thoroughly characterized using x-ray diffraction, electron paramagnetic resonance spectroscopy, nitrogen adsorption isotherms and Fourier Transform Infrared (FT-IR) spectroscopy. Copper ions were exchanged into nanocrystalline NaY to increase the catalytic activity. The reactions of nitrogen dioxides (NO{sub x}) and ammonia (NH{sub 3}) on nanocrystalline NaY and CuY were investigated using FT-IR spectroscopy. Significant conversion of NO{sub 2} was observed at room temperature in the presence of NH{sub 3} as monitored by FT-IR spectroscopy. Copper-exchanged nanocrystalline NaY was more active for NO{sub 2} reduction with NH{sub 3} relative to nanocrystalline NaY.

Authors:
;
Publication Date:
Research Org.:
University Of Iowa
Sponsoring Org.:
USDOE
OSTI Identifier:
921000
DOE Contract Number:
FG26-06NT42739
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 74 ATOMIC AND MOLECULAR PHYSICS; ADSORPTION ISOTHERMS; AMMONIA; CATALYSIS; CATALYSTS; COPPER IONS; ELECTRON SPIN RESONANCE; MASS TRANSFER; NITROGEN; NITROGEN DIOXIDE; POWER PLANTS; SELECTIVE CATALYTIC REDUCTION; SPECTROSCOPY; SURFACE AREA; X-RAY DIFFRACTION; ZEOLITES

Citation Formats

Sarah C. Larson, and Vicki H. Grassian. Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx. United States: N. p., 2006. Web. doi:10.2172/921000.
Sarah C. Larson, & Vicki H. Grassian. Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx. United States. doi:10.2172/921000.
Sarah C. Larson, and Vicki H. Grassian. Sun . "Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx". United States. doi:10.2172/921000. https://www.osti.gov/servlets/purl/921000.
@article{osti_921000,
title = {Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx},
author = {Sarah C. Larson and Vicki H. Grassian},
abstractNote = {Nanocrystalline zeolites with discrete crystal sizes of less than 100 nm have different properties relative to zeolites with larger crystal sizes. Nanocrystalline zeolites have improved mass transfer properties and very large internal and external surface areas that can be exploited for many different applications. The additional external surface active sites and the improved mass transfer properties of nanocrystalline zeolites offer significant advantages for selective catalytic reduction (SCR) catalysis with ammonia as a reductant in coal-fired power plants relative to current zeolite based SCR catalysts. Nanocrystalline NaY was synthesized with a crystal size of 15-20 nm and was thoroughly characterized using x-ray diffraction, electron paramagnetic resonance spectroscopy, nitrogen adsorption isotherms and Fourier Transform Infrared (FT-IR) spectroscopy. Copper ions were exchanged into nanocrystalline NaY to increase the catalytic activity. The reactions of nitrogen dioxides (NO{sub x}) and ammonia (NH{sub 3}) on nanocrystalline NaY and CuY were investigated using FT-IR spectroscopy. Significant conversion of NO{sub 2} was observed at room temperature in the presence of NH{sub 3} as monitored by FT-IR spectroscopy. Copper-exchanged nanocrystalline NaY was more active for NO{sub 2} reduction with NH{sub 3} relative to nanocrystalline NaY.},
doi = {10.2172/921000},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Dec 31 00:00:00 EST 2006},
month = {Sun Dec 31 00:00:00 EST 2006}
}

Technical Report:

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  • The U. S. Department of Energy (DOE), Electric Power Research Institute (EPRI), Pennsylvania Electric Energy Research Council, (PEERC), New York State Electric and Gas and GPU Generation, Inc. jointly funded a demonstration to determine the capabilities for Hybrid SNCR/SCR (Selective Non-Catalytic Reduction/Selective Catalytic Reduction) technology. The demonstration site was GPU Generation's Seward Unit No.5 (147MW) located in Seward Pennsylvania. The demonstration began in October of 1997 and ended in December 1998. DOE funding was provided through Grant No. DE-FG22-96PC96256 with T. J. Feeley as the Project Manager. EPRI funding was provided through agreements TC4599-001-26999 and TC4599-002-26999 with E. Hughes asmore » the Project Manager. This project demonstrated the operation of the Hybrid SNCR/SCR NO{sub x} control process on a full-scale coal fired utility boiler. The hybrid technology was expected to provide a cost-effective method of reducing NO{sub x} while balancing capital and operation costs. An existing urea based SNCR system was modified with an expanded-duct catalyst to provide increased NO{sub x} reduction efficiency from the SNCR while producing increased ammonia slip levels to the catalyst. The catalyst was sized to reduce the ammonia slip to the air heaters to less than 2 ppm while providing equivalent NO{sub x} reductions. The project goals were to demonstrate hybrid technology is capable of achieving at least a 55% reduction in NO{sub x} emissions while maintaining less than 2ppm ammonia slip to the air heaters, maintain flyash marketability, verify the cost benefit and applicability of Hybrid post combustion technology, and reduce forced outages due to ammonium bisulfate (ABS) fouling of the air heaters. Early system limitations, due to gas temperature stratification, restricted the Hybrid NO{sub x} reduction capabilities to 48% with an ammonia slip of 6.1 mg/Nm{sup 3} (8 ppm) at the catalyst inlet. After resolving the stratification problem, the catalyst did not have sufficient activity in order to continue the planned test program. Arsenic poisoning was found to be the cause of premature catalyst deactivation.« less
  • The report documents the travels of a four-member study team in Japan during March 1980 to assess NOx flue gas treatment (FGT) technology and related areas. Overall goals of the study were to obtain new information on current issues concerning application of FGT technology and to update information previously published. A total of 28 equipment vendors, process operators, government agencies, and industry groups were contacted. Substantial recent progress was discovered with regard to commercial applications of selective catalytic reduction (SCR) technology to gas- and oil-fired boilers. There are several applications where SCR systems are operated continuously and are successfully removingmore » 80% of the NOx from the flue gas stream. Current development and demonstration efforts are aimed at applying SCR technology to coal-fired boilers since that fraction of Japan's total electric power generation is expected to increase to 12.5% in 1995 and since most of the new coal-fired boilers will use FGT technology for NOx control. Since four SCR systems on coal-fired boilers are scheduled to start up in 1980 and 1981, the Japanese activity in the NOx control field should be of considerable interest in the U.S. for at least the next 4 years.« less
  • The report gives results of a study of the impact of the ammonia leaving a nitrogen oxide (NOx) selective catalytic reduction (SCR) process on downstream flue gas cleaning processes. (NOx emissions from electric utility boilers may be reduced 80-90% by the application of pollution control technology based on the SCR of NOx with ammonia; however, some unreacted ammonia may be emitted from the control system.) These processes include electrostatic precipitators (ESPs), baghouses, and flue gas desulfurization (FGD) systems. In normal operation, most ammonia leaving the SCR system will be removed, either as particulate salts by the particulate removal system ormore » as free ammonia by the FGD system. Very little ammonia should be emitted at the stack. The operation of ESPs and FGD systems will, in most cases, be improved by the presence of ammonia in the flue gas. The effects of ammonia and ammonia salts on baghouse operation are not known. At normally expected emission levels, no adverse environmental impacts are projected; however, at high ammonia emission levels, the potential exists for problems with ammonia in the waste streams from fly ash and SO2 collection devices. Potential adverse environmental impacts exist in the ash and sludge ponds where collected ammonia may be concentrated and emitted as a gaseous pollutant.« less
  • The report documents actual costs, reliability, and operational characteristics of commercial SCR systems to control nitrogen oxides (NOx) for small prime movers. A database was developed via telephone survey and site visits, and data were analyzed to evaluate SCR systems under anticipated operating conditions. The report presents details (e.g., unit numbers, location, fuel type, new vs. retrofit installations, operating status, load characteristics, and operating system parameters) on all sites where SCR is used on turbines and internal combustion engines (less than 15,000 hp).
  • This paper describes the status of the Innovative Clean Coal Technology project to demonstrate SCR technology for reduction of NOx emissions from flue gas of utility boilers burning U.S. high-sulfur coal. The project is sponsored by the U.S. Department of Energy, managed and co- funded by Southern Company Services, Inc. on behalf of the Southern Company, and also co-funded by the Electric Power Research Institute and Ontario Hydro; and is located at Gulf Power Company`s Plant Crist Unit 5 (75 MW tangentially-fired boiler burning U.S. coals that have a sulfur content near 3.0%), near Pensacola, Florida. The test program ismore » being conducted for approximately two years to evaluate catalyst deactivation and other SCR operational effects. The SCR test facility has nine reactors: three 2.5 MW (5000 scfm), and six 0.2 MW(400 scfm). Eight reactors operate on high-dust flue gas, while the ninth reactor operates on low-dust flue gas using a slip stream at the exit of the host unit`s hot side precipitator. The reactors operate in parallel with commercially available SCR catalysts obtained from vendors throughout the world. Long-term performance testing began in July 1993. A general test facility description and the results from three parametric test sequences and long term test data through December 1994 are presented in this paper.« less