Hydrolysis Catalyst Coating for SCR Reactor Deposit Mitigation

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Solution Overview

Problem

Urea deposits in selective catalytic reduction (SCR) systems lead to corrosion, erosion, and emissions compliance failures due to the buildup of urea byproducts, which are not effectively addressed by existing hydrolysis catalyst coatings in reductant decomposition reactors.

Innovation Solution

A hydrolysis catalyst coating is applied to various regions within the after-treatment system, including the reductant decomposition reactor, to rapidly decompose urea and urea-based deposits into ammonia, preventing their formation and reducing corrosion, and allowing for the use of less expensive materials like stainless steel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If urea dosing is used in SCR systems, then nitrogen oxide reduction is achieved, but urea deposits form causing corrosion and erosion

Engineering Contradiction:

Improveemissions complianceVSAvoidurea deposit corrosion and erosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A hydrolysis catalyst coating is applied to the reactor surfaces as an intermediary layer between the urea solution and the metallic reactor walls. This catalyst coating facilitates the decomposition of urea into ammonia and carbon dioxide, preventing the formation of harmful urea deposits that would otherwise cause corrosion and erosion of the reactor components.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The hydrolysis catalyst coating changes the chemical reaction parameters by providing an alternative reaction pathway with lower activation energy. This enables urea decomposition to occur efficiently at lower temperatures and shorter residence times, preventing deposit formation while maintaining emissions compliance. The coating modifies the local chemical environment to favor complete decomposition over deposit formation.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional materials are used in reductant decomposition reactor, then manufacturing cost is reduced, but component lifetime is shortened due to corrosion

Engineering Contradiction:

Improvemanufacturing costVSAvoidcomponent lifetime

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The solution employs a composite structure combining conventional metallic reactor materials with a hydrolysis catalyst coating layer. This composite approach allows the use of cost-effective base materials while the protective catalyst coating provides corrosion and erosion resistance, extending component lifetime without significantly increasing manufacturing cost.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The hydrolysis catalyst coating acts as a sacrificial protective layer that can be applied to inexpensive reactor materials. The coating itself serves as the durable element, allowing the use of cheaper base materials that would otherwise corrode quickly, thereby reducing overall system cost while maintaining extended component lifetime.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Use of energy by moving object

If low temperature operation is used in decomposition reactor, then energy consumption is reduced, but urea decomposition efficiency decreases

Engineering Contradiction:

Improveenergy consumptionVSAvoidurea decomposition efficiency

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent replaces thermal energy input with a catalytic mechanism for urea decomposition. Instead of relying solely on high temperature to drive the decomposition reaction, the hydrolysis catalyst coating enables the reaction to proceed efficiently at lower temperatures, substituting thermal energy with catalytic activity and thereby reducing energy consumption while maintaining decomposition efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 hydrolysis catalyst coating enhances ammonia generation kinetics, eliminates harmful byproducts, and lowers urea dosing temperature, improving the efficiency and durability of the after-treatment system, enabling urea dosing in previously impractical regimes and extending component lifetime.

Implementation Method 1

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

the hydrolysis catalyst coating decomposes the urea and the urea based deposits into ammonia in a short residence time

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS8114364B2Increased reductant decomposition reactor robustness through the use of a hydrolytic catalyst coating

Publication Date: 2012.02.14 CUMMINS FILTRATION IP INC

AI summary

A means for increasing the robustness of a SCR after-treatment system is provided. Specifically, a hydrolysis catalyst coating is applied to multiple surfaces within a decomposition reactor to aid in urea and urea based deposit decomposition and mitigation of urea based deposits. The reactor includes an injector mount attached to a middle tube portion, an inlet tube, an outlet tube and a mixer. A hydrolysis catalyst coating is applied to an inner surface of the injector mount, an inner surface of the middle tube portion, an inner surface of the outlet tube and an outer edge of the mixer. The hydrolysis catalyst coating is capable of decomposing urea and urea based deposits that comes in contact with the hydrolysis catalyst coating and mitigates the formation of urea based deposits.