Diesel Oxidation Catalyst Sulfur Capture Region
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Solution Overview
Problem
Diesel engines produce exhaust gases containing sulfur-containing impurities that poison catalytically active metals in emissions control devices, leading to reduced activity and environmental concerns such as acid rain formation.
Innovation Solution
An oxidation catalyst system featuring a capture material with a metal that reacts with sulfur oxides and refractory oxide particles with a low specific surface area, combined with a catalytic region containing platinum group metals, effectively traps sulfur impurities, preventing degradation of the catalyst and downstream emissions control devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfur-containing impurities are present in diesel exhaust gas, then the exhaust gas can be treated by conventional oxidation catalysts, but the catalytically active metals are poisoned leading to reduced activity
Solution Approach 1:
A capture material comprising metal particles and refractory oxide particles is introduced as an intermediary between the sulfur-containing exhaust gas and the oxidation catalyst. The capture material selectively reacts with sulfur oxides to form sulfates, preventing sulfur from reaching and poisoning the catalytically active metals in the oxidation catalyst, thus protecting catalyst activity while allowing exhaust treatment to proceed
Solution Approach 2:
The harmful sulfur-containing impurities are extracted from the exhaust gas stream by the capture material before the gas reaches the oxidation catalyst. The capture material removes sulfur oxides through chemical reaction, separating the harmful component from the exhaust gas and preventing it from affecting the catalyst's performance
2Reliability
If sulfur oxides are removed from exhaust gas, then downstream emissions control devices are protected, but additional capture material and refractory oxide particles are required
Solution Approach 1:
The capture material combines multiple functional components into a single integrated material system: metal particles provide sulfur oxidation activity, refractory oxide particles provide structural support and sulfate storage capacity, and their composite structure creates a monolithic capture region that can be directly integrated into the oxidation catalyst, eliminating the need for separate sulfur removal devices
Solution Approach 2:
The capture material performs multiple functions simultaneously: it oxidizes sulfur oxides to sulfates, provides structural support for the catalyst, and can be integrated into the oxidation catalyst itself, making the system versatile and reducing the need for additional separate emissions control devices
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 system maintains oxidative activity towards carbon monoxide, hydrocarbons, and nitric oxide, while protecting downstream emissions control devices from sulfur poisoning, ensuring sustained performance and environmental compliance.
Implementation Method 1
a capture material for capturing at least one sulfur containing impurity in the exhaust gas produced by the diesel engine; wherein the capture material comprises a metal for reacting with an oxide of sulfur in the exhaust gas
Implementation Method 2
particles of a refractory oxide, preferably wherein the particles of the refractory oxide have a mean specific surface area ≤50 m2/g
Implementation Method 3
a catalytic region disposed on the substrate; wherein the catalytic region comprises a catalytic material comprising a platinum group metal (PGM) selected from the group consisting of platinum (Pt), palladium (Pd) and a combination of platinum (Pt) and palladium (Pd)
Data Source
AI summary
An oxidation catalyst is described for treating an exhaust gas produced by a diesel engine. The oxidation catalyst comprises: a substrate; a capture material for capturing at least one sulfur containing impurity in the exhaust gas produced by the diesel engine; wherein the capture material comprises a metal for reacting with an oxide of sulfur in the exhaust gas and particles of a refractory oxide, wherein the particles of the refractory oxide have a mean specific surface area ≤50 m2/g; and a catalytic region disposed on the substrate; wherein the catalytic region comprises a catalytic material comprising a platinum group metal (PGM) selected from the group consisting of platinum (Pt), palladium (Pd) and a combination of platinum (Pt) and palladium (Pd).