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Mixed metal large crystal molecular sieve catalyst compositions, catalytic articles, systems and method

A molecular sieve and product technology, applied in the field of selective catalytic reduction catalysts, can solve the problems of poor conversion rate, poor hydrothermal stability, decreased catalytic activity, etc.

Active Publication Date: 2017-08-29
BASF CATALYSTS (SHANGHAI) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Prior to the discovery of the metal-promoted zeolites described in U.S. Patent No. 7,601,662, although many metal-promoted zeolites had been proposed in the patent and scientific literature for use as SCR catalysts, each proposed material suffered from one or all of the following drawbacks: (1) poor conversion of nitrogen oxides at low temperatures, such as 350°C and lower; and (2) poor hydrothermal stability manifested by a significant drop in catalytic activity in the conversion of nitrogen oxides by SCR

Method used

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  • Mixed metal large crystal molecular sieve catalyst compositions, catalytic articles, systems and method
  • Mixed metal large crystal molecular sieve catalyst compositions, catalytic articles, systems and method
  • Mixed metal large crystal molecular sieve catalyst compositions, catalytic articles, systems and method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0117] Example 1 - Preparation of large crystal Cu-CHA

[0118] The organic template (TMAOH and TMAA), to prepare CuCHA powder catalyst. Ludox AS40 was used as silicon source, while aluminum triisopropoxide was used as aluminum source. After adding the two templates, the resulting pH of the gel was approximately 14.2. The synthesized gel was transferred to an autoclave for hydrothermal crystallization at 170° C. for 24 hours with a stirring rate of 200 RPM.

[0119] After hydrothermal crystallization, the resulting suspension had a pH of 12.6. The suspension is mixed with deionized water and filtered with a porcelain suction filter directly or with the aid of a flocculant. The wet product was then heated to a temperature of 120° C. for 4 hours in air. The dried product was then further calcined in air at 600° C. for 5 hours to remove the template and ensure a C content of less than 0.1 wt%. The calcined product is thus ready for ion exchange with Cu to obtain a metal-con...

Embodiment 2

[0123] Example 2 - Preparation of Fe-CHA

[0124] The FeCHA powder catalyst was prepared by ion exchange by calcining CHA (traditionally made with a crystal size of less than 0.5 microns) at 80°C and pH 4 for 2 hours. The mixture was then washed with deionized water, filtered and vacuum / air dried. A slurry of Fe-CHA was prepared to 45% target solids and 2.5% ZrOAc binder was added based on zeolite solids. Mix the slurry well, then grind to 7-10 micron D 90 %.

Embodiment 3

[0125] Example 3 - Preparation of large crystal Fe-CHA

[0126] FeCHA powder catalyst was prepared by ion exchange of calcined CHA prepared according to the method of Example 1 at 80°C and pH 4 for 2 hours. The mixture was then washed with deionized water, filtered and vacuum / air dried. A slurry of Fe-CHA was prepared to 45% target solids and 2.5% ZrOAc binder was added based on zeolite solids. Mix the slurry well, then grind to 7-10 micron D 90 %.

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Abstract

Described are compositions and catalytic articles comprising both a first molecular sieve promoted with copper and a second molecular sieve promoted with iron, the first and second molecular sieves having a d6r unit and the first molecular sieves having cubic shaped crystals with an average crystal size of about 0.5 to about 2 microns. The weight ratio of the copper-promoted molecular sieve to the iron-promoted molecular sieve can be about 1:1 to about 4:1. The catalytic articles are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.

Description

field of invention [0001] The present invention relates generally to the field of selective catalytic reduction catalysts and methods of making and using such catalysts for the selective reduction of nitrogen oxides. Background of the invention [0002] For a long time, nitrogen oxides (NO x ) harmful components have caused air pollution. Contains NO in, for example, exhaust gases from internal combustion engines such as cars and trucks, from combustion facilities such as power stations heated by natural gas, oil or coal, and from nitric acid production plants x . [0003] Various treatments have been used to treat NO-containing x gas mixture to reduce air pollution. One type of treatment involves the catalytic reduction of nitrogen oxides. There are two methods: (1) a non-selective reduction method in which carbon monoxide, hydrogen or a lower hydrocarbon is used as a reducing agent; and (2) a selective reduction method in which ammonia or an ammonia precursor is used ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/72B01D53/86B01D53/94B01D53/56
CPCB01D53/8628B01D53/9418B01J29/723B01D2257/404B01D2255/9022B01D2255/9032B01D2255/9202B01D2255/20738B01D2255/20761B01D2255/50B01J2235/00B01J2235/30B01J35/56B01J35/77B01J37/0246B01J29/80B01J37/0244C01B39/48B01J2229/186B01J29/763Y02A50/20B01J35/19B01J29/72B01J37/0248B01J29/87B01J29/86B01J29/7638B01J29/83B01J29/76B01J29/85B01J29/84B01J29/89B01J35/30
Inventor J·L·莫哈南J·杨P·伯克K·E·福斯
Owner BASF CATALYSTS (SHANGHAI) CO LTD