Unblocking SCR Catalyst Pores via Liquid Soak and Steam
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Solution Overview
Problem
Selective Catalytic Reduction (SCR) catalysts face durability issues due to pore blocking, which reduces their NOx conversion performance over time, and existing methods either replace the entire muffler or reactivate metal ions, but there is no method to unblock pores and restore catalyst efficiency.
Innovation Solution
A method involving filling the SCR catalyst with a liquid, allowing it to soak and penetrate into the zeolite pores, draining excess liquid, and heating to vaporize and remove obstructions, thereby unblocking pores and restoring catalyst efficiency without replacing the muffler.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire muffler is replaced to restore SCR catalyst performance, then the NOx conversion performance is improved, but the cost and complexity of the solution increases significantly
Solution Approach 1:
The patent extracts and removes the obstructions blocking the pores of the zeolite catalyst using a chemical treatment process. A liquid solution is introduced to the catalyst, allowing it to penetrate and dissolve the obstructions (such as sulfates, carbon deposits, or other contaminants) that are blocking the active sites, thereby restoring the catalyst's porosity and NOx conversion performance without replacing the entire muffler assembly
Solution Approach 2:
The patent changes the chemical parameters of the catalyst by introducing a liquid solution that alters the composition within the pores. The solution contains chemicals that react with or dissolve the obstructions, changing the physical and chemical state of the blocked pores back to their original functional state, thus restoring catalyst activity without mechanical replacement
2Duration of action of moving object
If the SCR catalyst is used continuously without maintenance, then the operational time is extended, but the pore blocking increases and reduces catalytic activity
Solution Approach 1:
The patent implements a periodic regeneration process where the SCR catalyst is treated with a liquid solution at intervals during its service life. This periodic maintenance restores the catalyst's pore structure and active sites by removing accumulated obstructions, allowing the catalyst to maintain high NOx conversion performance throughout its operational lifespan rather than degrading continuously
Solution Approach 2:
The patent enables the catalyst to undergo self-regeneration through a treatment process that can be performed in-situ without removing the catalyst from the muffler. The liquid solution is introduced directly to the catalyst bed, allowing the catalyst to restore its own functionality autonomously through chemical dissolution of obstructions, eliminating the need for external replacement or complex disassembly
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 method effectively recovers the SCR catalyst's efficiency by re-establishing access to active sites, extending its durability and maintaining NOx conversion performance without the need for muffler replacement.
Implementation Method 1
a step of soaking during which a proportion of the liquid introduced inside the muffler spreads into the pores of the zeolite
Implementation Method 2
a step of drying, at which the SCR catalyst is heated at a temperature above the ebullition temperature of the liquid so as to vaporize the liquid remaining in the pores and generate steam flows through the obstructions, the steam flows removing the obstructions and unblocking the pores
Data Source
AI summary
The invention concerns a method for unblocking pores in a metal zeolite based selective catalytic reduction (SCR) catalyst. The method includes filling, at least partially, the SCR catalyst with a liquid, the liquid being preferably distilled water. The method includes letting said liquid inside the SCR catalyst enough time to allow said liquid to dissolve, at least partially, the obstructions and to penetrate into the pores. The method includes heating the SCR catalyst at a temperature above the ebullition temperature of the liquid so as to vaporize the part of the liquid remained into the pores, and generate steam flows through the obstructions, the steam flows removing the obstructions and unblocking the pores, wherein no hydrocarbons are injected during the step of heating.