Zeolite Catalyst Body Soaking Transition Metal Oxide
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Solution Overview
Problem
Current methods for manufacturing catalyst bodies for engine exhaust systems, such as zeolite-based honeycomb bodies, face challenges in achieving efficient nitrogen oxide (NOx) reduction across a broad temperature range without the need for excessive washcoating, which can lead to decreased catalytic performance and increased backpressure.
Innovation Solution
A method involving soaking a fired zeolite-based body in a transition metal oxide solution, followed by exposure to a humidified atmosphere, drying, and calcining, which results in a catalyst body with a primary phase of zeolite and a honeycomb or foam structure, capable of achieving greater than 75% NOx reduction from 250°C to 600°C without the need for a washcoating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If washcoating is applied to honeycomb substrates to improve catalytic performance, then NOx reduction capability is improved, but backpressure increases and catalytic performance decreases
Solution Approach 1:
The patent removes the washcoating layer from the catalyst system and instead incorporates transition metal oxides directly into the zeolite body through soaking and calcining processes. This extraction of the washcoating step eliminates the harmful backpressure effect while maintaining NOx reduction capability through the integrated metal oxide-zeolite structure
Solution Approach 2:
The patent creates a composite material by combining transition metal oxides with zeolite through a multi-step process involving soaking, humidified atmosphere exposure, drying, and calcining. This composite structure integrates the catalytic activity of metal oxides with the porous framework of zeolite, achieving NOx reduction without requiring separate washcoating layers that would increase backpressure
2Reliability
If washcoating is applied to honeycomb substrates to improve catalytic performance, then NOx reduction capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the catalyst formation process with the substrate manufacturing process by soaking the zeolite body in transition metal oxide solution and calcining it in-situ. This eliminates the need for separate washcoating operations and reduces manufacturing complexity by integrating multiple functions into a single process flow
Solution Approach 2:
The patent performs preliminary soaking of the zeolite body in transition metal oxide solution before final calcining, allowing the metal oxide to be pre-loaded into the zeolite structure. This preliminary action simplifies the overall manufacturing process by avoiding the need for complex washcoating applications and multiple processing steps
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 method provides a catalyst body that achieves significant NOx reduction across a broad temperature range, minimizing ammonia slip and reducing the need for high surface area washcoating, thereby improving catalytic performance and reducing backpressure in engine exhaust systems.
Implementation Method 1
soaking at least part of a fired zeolite-based body in a transition metal oxide solution
Implementation Method 2
drying the body
Implementation Method 3
exposing the body to a humidified atmosphere at one or more temperatures above 20° C.
Implementation Method 4
calcining the body
Data Source
AI summary
A method of manufacturing a catalyst body which includes: soaking at least part of a fired zeolite-based body in a transition metal oxide solution; removing the body from the transition metal oxide solution; exposing the body to a humidified atmosphere at one or more temperatures above 20° C.; then drying the body; and calcining the body.