SAPO-34 Catalyst Hydrothermal Stability for SCR

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

There is a need for improved microporous crystalline materials with enhanced performance and hydrothermal stability for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) in exhaust gases, as existing zeolitic catalysts face challenges in retaining surface area and micropore volume under elevated temperatures and humidity.

Innovation Solution

A microporous crystalline silicoaluminophosphate (SAPO) material with pore openings ranging from 3 to 5 Angstroms, comprising metals from the alkali-earth, rare-earth, or alkali groups, and copper, exhibiting excellent hydrothermal stability and used in forms like channeled or honeycombed-shaped bodies for SCR processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional zeolitic catalysts are used for SCR of NOx, then catalytic activity is achieved, but hydrothermal stability deteriorates with loss of surface area and micropore volume under elevated temperatures and humidity

Engineering Contradiction:

Improvehydrothermal stabilityVSAvoidsurface area and micropore volume

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent employs composite materials by combining multiple metal components (copper, iron, and rare-earth metals such as lanthanum, cerium, or neodymium) within a microporous crystalline structure (SAPO-34 or SAPO-41). This composite approach enhances hydrothermal stability while maintaining catalytic activity for NOx reduction, as the synergistic interaction between different metals reinforces the structural integrity under harsh conditions.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the catalyst by incorporating specific ratios of copper (0.5-10 wt%), iron (0.5-10 wt%), and rare-earth metals (0.1-5 wt%) into the microporous crystalline framework. These parameter changes optimize both the catalytic performance and resistance to hydrothermal degradation, preventing collapse of the micropore structure.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If microporous crystalline material is exposed to high temperatures and humidity during SCR process, then NOx conversion occurs, but surface area and micropore volume are lost

Engineering Contradiction:

ImproveNOx conversion efficiencyVSAvoidsurface area and micropore volume

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent optimizes the metal composition parameters within the microporous structure, specifically incorporating copper (0.5-10 wt%) and iron (0.5-10 wt%) along with rare-earth metals, to maintain catalytic activity for NOx conversion while resisting structural degradation at elevated temperatures and humidity conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The synergistic combination of multiple metal oxides (copper oxide, iron oxide, and rare-earth metal oxides) within the SAPO-34 or SAPO-41 framework creates a composite catalyst that simultaneously achieves high NOx conversion efficiency and maintains structural integrity under reactive exhaust conditions.

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The material retains at least 70% of its surface area and micropore volume after exposure to high temperatures and humidity, demonstrating improved NOx conversion efficiency and stability, particularly when used in SCR processes for diesel exhausts and coal-fired power plants.

Implementation Method 1

selective catalytic reduction (SCR) of nitrogen oxides (NOx) in exhaust gases

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

microporous crystalline material having pore opening ranging from 3 to 5 Angstroms

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS9981256B2Stabilized microporous crystalline material, the method of making the same, and the use for selective catalytic reduction of NO<sub>x </sub>

Publication Date: 2018.05.29 ADVANCED MATERIALS & CATALYSTS LLC

AI summary

There is disclosed a microporous crystalline material having pore opening ranging from 3 to 5 Angstroms, where the material comprises a first metal chosen from alkali earth group, rare earth group, alkali group, or mixtures thereof, and a second metal chosen from iron, copper or mixtures thereof; and has a molar silica to alumina ratio (SAR) from 3 to 10. The microporous crystalline material disclosed herein may comprise a crystal structure having building units of double-6-rings (d6r) and pore opening of 8-rings as exemplified with framework types defined by the Structure Commission of the International Zeolite Association having structural codes of CHA, LEV, AEI, AFT, AFX, EAB, ERI, KFI, SAT, TSC, and SAV. There is also disclosed a method of selective catalytic reduction of nitrogen oxides in exhaust gas, comprising at least partially contacting the exhaust gases with an article comprising the disclosed microporous crystalline material.