Ammonia Generating Apparatus for SCR Systems

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Solution Overview

Problem

Inefficient ammonia generation in exhaust aftertreatment systems leads to reductant deposits, reducing system efficiency and requiring frequent maintenance, especially at low temperatures where exhaust gas heat is insufficient for decomposing reductant into ammonia.

Innovation Solution

An ammonia generating apparatus with heating coils within a housing to thermolyze reductant, producing ammonia independent of exhaust gas conditions, and a hydrolysis catalyst to convert reaction byproducts into ammonia, ensuring efficient ammonia production and reducing reductant deposits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If reductant is injected into exhaust gas for ammonia generation, then ammonia is produced for SCR system, but reductant deposits form in exhaust tube and components

Engineering Contradiction:

Improveammonia generation efficiencyVSAvoidsystem maintenance frequency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces an intermediary heating zone between the reductant injection point and the SCR system. This heating zone acts as a mediator that ensures complete vaporization and thermal decomposition of the reductant before it enters the SCR system, preventing direct contact between liquid reductant and exhaust tube surfaces that would cause deposit formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the temperature parameter in the reductant injection zone by implementing active heating elements. This increases the local temperature to ensure rapid vaporization of the reductant, transforming it from liquid phase to gas phase before entry into the exhaust system, thereby eliminating the condition for deposit formation.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If reductant is injected at low temperatures, then exhaust gas heat is insufficient for decomposing reductant, but ammonia generation is reduced

Engineering Contradiction:

Improveexhaust gas temperatureVSAvoidammonia generation rate

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The patent applies preliminary heating action before the reductant enters the exhaust gas flow. By pre-heating the reductant in a dedicated heating zone, the system ensures that the reductant is fully vaporized and decomposed before mixing with the exhaust gas, overcoming the limitation of low exhaust gas temperatures.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the passive reliance on exhaust gas heat with an active thermal processing system. Instead of depending on the exhaust gas temperature to decompose the reductant, the system uses electric or catalytic heating elements to provide the necessary thermal energy for reductant decomposition.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If reductant deposits are allowed to accumulate, then system efficiency decreases, but frequent cleaning is required

Engineering Contradiction:

Improvesystem efficiencyVSAvoidmaintenance time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary anti-action by implementing heating measures that prevent reductant deposits from forming in the first place. By maintaining sufficient temperature in the reductant injection and mixing zones, the system creates conditions where reductant completely vaporizes and mixes with exhaust gas, eliminating the precursor for deposit formation and thereby preventing the need for frequent cleaning.

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

Facilitates high catalytic conversion efficiency of SCR systems at low temperatures, minimizes reductant deposits, and integrates seamlessly with existing aftertreatment systems, reducing maintenance needs and costs.

Implementation Method 1

the heating coil assembly is configured to generate heat sufficient to thermolyze the reductant to generate ammonia and reaction byproducts

Methodology Applied

Scientific EffectThermolysis: Thermolysis

Implementation Method 2

A hydrolysis catalyst may be disposed downstream of the one or more coils and is configured to catalyze conversion of reaction byproducts of the thermolysis reaction into ammonia

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

a hydrolysis catalyst disposed downstream of the one or more coils and is configured to catalyze conversion of reaction byproducts of the thermolysis reaction into ammonia

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS11753979B2Systems and methods for generating ammonia

Publication Date: 2023.09.12 CUMMINS EMISSION SOLUTIONS INC

AI summary

An ammonia generating apparatus comprises a housing comprising a first end wall on which a reductant injector configured to insert a reductant into the housing is mountable. A heating coil assembly is disposed within the housing. A first end of the heating coil assembly is located proximate to a location of the first end wall where a reductant injector tip of the reductant injector is located when the reductant injector is mounted on the first end wall. The heating coil assembly is configured to generate heat sufficient to thermolyze the reductant to generate ammonia and reaction byproducts, in response to an electric current being passed therethrough. A hydrolysis catalyst can be disposed downstream of the heating coil assembly for catalyzing hydrolysis of the reaction byproducts into ammonia.