Catalyst Filter Coating via Air-Blown Slurry Injection

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Solution Overview

Problem

Existing methods for coating exhaust gas purification filters with catalyst slurry face challenges such as inconsistent slurry distribution, porosity limitations, and difficulty in achieving precise control over the amount of coated slurry, which affects catalytic activity and compliance with exhaust gas regulations.

Innovation Solution

A method involving the PnP (Push-and-Pull) technique, where a predetermined amount of catalyst slurry is injected into the filter and air pressure is used to control the distribution, ensuring uniform coating on the inner wall surface of filter cells, regardless of filter porosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the dipping method is used to coat catalyst slurry on the filter, then the filter can be coated with catalyst material, but the slurry distribution cannot be controlled accurately and the coated amount varies

Engineering Contradiction:

Improveslurry distribution controlVSAvoidcoating process complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The filter is divided into multiple sections along its length, with each section being coated independently. The coating apparatus includes multiple nozzles positioned at different locations that can be controlled separately, allowing precise control of slurry distribution in each section of the filter.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The traditional mechanical dipping method is replaced with a gas-phase coating method where catalyst slurry is transported through a carrier gas and deposited onto the filter using controlled gas flow and heating, enabling better control over slurry distribution and amount coated.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the porosity of the filter is high, then the filter can maintain good filtration performance, but the catalyst slurry cannot be effectively coated due to excessive porosity

Engineering Contradiction:

Improvefiltration performanceVSAvoidcoating consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The coating process parameters including temperature, gas flow rate, and slurry concentration are adjusted to optimize coating on high porosity filters. The heating zone temperature and gas flow rate are controlled to ensure slurry deposits uniformly even on highly porous surfaces without being absorbed too rapidly.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a large amount of catalyst slurry is coated, then catalytic activity is improved, but the backpressure increases and exhaust gas flow is restricted

Engineering Contradiction:

Improvecatalytic activityVSAvoidbackpressure

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

Different sections of the filter are coated with different amounts of catalyst slurry based on local requirements. The coating amount is optimized in each section to achieve sufficient catalytic activity while maintaining acceptable backpressure, allowing variation in coating density along the filter length.

Inventive Principle:

Principle #3Local quality

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

This method allows for precise control of slurry distribution, improving catalytic performance by adjusting backpressure and maintaining catalytic activity, while also ensuring compliance with exhaust gas regulations.

Implementation Method 1

blowing air into the catalyst filter from an end of the catalyst filter to control the slurry distribution on the inner wall surface

Methodology Applied

Scientific EffectAir pressure: Pressure Increase

Implementation Method 2

the catalyst slurry injected into the filter has an appropriate viscosity and particle size so as to pass through pores formed in the filter cell wall

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS12280366B2Method for coating exhaust gas purification catalyst filter with fixed amount of catalyst slurry

Publication Date: 2025.04.22 HEESUNG CATALYSTS CORP

AI summary

Described is a method of coating the inside of an exhaust gas purification catalyst filter with a predetermined amount of catalyst slurry while adjusting the distribution of catalyst components in or on a cell wall of the filter. A predetermined amount of catalyst slurry can be injected into an internal channel of a filter to solve conventional problems caused by excess or surplus slurry injection. The predetermined amount of slurry injected into the internal channel of the filter is coated on or in the cell wall, depending on the viscosity and particle size of the slurry. This enables a coating profile in which the slurry distribution at a front portion of the filter and the slurry distribution at a back portion of the filter differ from each other. In addition, the coating profile on the inner surface of the cell wall or in the pores of the cell wall can be adjusted through the subsequent air blowing, so that the back pressure of the filter and the performance of the catalyst filter, such as catalytic activity, can be improved. In addition, the coating length in the filter can be adjusted by controlling the pressure of air during the air blowing.