Exhaust Purification Adsorption Layer Sulfur Poisoning

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Solution Overview

Problem

Exhaust gas containing sulfur oxides impairs the function of reduction catalysts in exhaust purification devices, leading to a decline in the reduction of nitrogen oxides, as sulfur oxides react with silver in the catalyst, reducing its effectiveness.

Innovation Solution

An exhaust purification device with a reduction catalyst and a heating filter that captures particulates, a catalyst adding valve to spray diesel fuel, and an adsorption layer with solid acid metal oxide, which adsorbs ammonia to react with sulfur oxides and produce ammonium sulfate, then decomposes to sulfur dioxide, minimizing reactivity with silver and maintaining catalyst functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a reduction catalyst containing silver is used to promote reaction between hydrocarbons and nitrogen oxides, then nitrogen oxide reduction efficiency is improved, but sulfur oxides in exhaust gas react with silver to form compounds that impair catalyst function

Engineering Contradiction:

Improvenitrogen oxide reduction efficiencyVSAvoidcatalyst function stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A protective layer is introduced as an intermediary between the silver catalyst and sulfur oxides. This protective layer selectively allows nitrogen oxides to pass through while blocking sulfur oxides from reaching the silver catalyst, thereby preventing the harmful reaction between sulfur oxides and silver while maintaining nitrogen oxide reduction efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The catalyst is designed as a composite structure combining silver with other materials that have resistance to sulfur oxidation. This composite material approach allows the catalyst to maintain both high nitrogen oxide reduction activity and resistance to sulfur oxide poisoning simultaneously

Inventive Principle:

Principle #40Composite materials

2Productivity

If the reduction catalyst is exposed to sulfur oxides to treat nitrogen oxides, then exhaust purification is achieved, but the catalyst deteriorates due to sulfur compound formation

Engineering Contradiction:

Improveexhaust purification performanceVSAvoidcatalyst service life

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective layer is designed to preemptively block sulfur oxides before they can reach and damage the catalyst. This preliminary protective action prevents sulfur compound formation on the catalyst surface, extending catalyst service life while maintaining exhaust purification performance

Inventive Principle:

Principle #9Preliminary anti-action

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 solution effectively limits the decline in nitrogen oxide reduction by preventing sulfur oxides from impairing the reduction catalyst, ensuring consistent NOx reduction efficiency and extending catalyst lifespan.

Implementation Method 1

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

The adsorption layer is configured to adsorb ammonia produced in the catalyst layer

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

an amount of the acid sites of the adsorption layer is greater than an amount of the acid sites of the catalyst layer. The adsorption layer is configured to adsorb ammonia produced in the catalyst layer. The adsorption layer has a property of causing sulfur oxides contained in the exhaust gas to contact the adsorbed ammonia, thereby is configured to produce ammonium sulfate through a reaction of the adsorbed ammonia with sulfur trioxide or sulfur tetroxide

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 4

The heating portion is configured to increase the temperature of the exhaust gas to a predetermined temperature which is greater than or equal to a temperature at which the ammonium sulfate thermally decomposes, thereby is configured to produce sulfur dioxide that has less reactivity to the silver than the sulfur trioxide or the sulfur tetroxide has

Methodology Applied

Scientific EffectThermal decomposition: Thermolysis

Implementation Method 5

The catalyst layer is configured to promote a reduction reaction in which the nitrogen oxide reacts with hydrocarbon to produce ammonia

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 6

The catalyst layer is configured to promote a reduction reaction in which the nitrogen oxide reacts with hydrocarbon to produce ammonia

Methodology Applied

Scientific EffectReduction: Reduction

Data Source

PatentEP3181846B1Exhaust purification device

Publication Date: 2019.09.18 HINO MOTORS LTD

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AI summary

This exhaust purification device is provided with a reduction catalyst that reduces nitrogen oxides contained in exhaust. The reduction catalyst is provided with a catalyst layer and an adsorption layer covering the catalyst layer. The catalyst layer contains a catalyst support that supports silver. The adsorption layer contains a solid acid metal oxide that is acidic, and the acidity of the adsorption layer is greater than that of the catalyst layer. The adsorption layer has the characteristic of adsorbing ammonia generated at the catalyst layer, and causing the adsorbed ammonia to contact sulfur oxides contained in the exhaust.