Platinum Palladium Oxidation Catalyst for Diesel Exhaust Regeneration
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Solution Overview
Problem
Conventional purification systems for diesel engine exhaust gases face issues with high particulate matter accumulation leading to increased filter pressure, engine stoppages, and insufficient filter regeneration due to the thermal durability limitations of platinum-based catalysts and hydrocarbon adhesion at low temperatures.
Innovation Solution
A purification method using an oxidation catalyst supported by both platinum and palladium, refractory inorganic oxides coated on a 3-dimensional structure, which supplies hydrocarbon-based liquid to raise the exhaust gas temperature above 550°C for effective filter regeneration, even at high temperatures, and prevents carbon-containing component adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum-based oxidation catalyst is used for filter regeneration, then combustion reaction can be initiated, but thermal durability is insufficient at high temperatures leading to insufficient regeneration after long period
Solution Approach 1:
The patent uses a composite oxidation catalyst containing both platinum and palladium on a refractory oxide carrier. This composite structure combines the high catalytic activity of platinum with the superior thermal stability of palladium, enabling effective regeneration at high temperatures (600-800°C) while maintaining durability over extended periods. The refractory oxide carrier further enhances thermal resistance.
2Ease of operation
If hydrocarbon is supplied for filter regeneration at low temperature, then combustion reaction can occur, but carbon-containing components adhere to the catalyst
Solution Approach 1:
The patent changes the operational temperature parameter from low temperature to high temperature (600-800°C) for filter regeneration. At this elevated temperature range, the oxidation catalyst effectively combusts accumulated particulates while preventing carbon-containing components from adhering to the catalyst surface. The high temperature ensures complete oxidation and eliminates the adhesion problem that occurs at lower temperatures.
3Temperature
If high concentration of hydrocarbon is combusted for filter regeneration, then heat supply is sufficient, but thermal durability requirement increases due to high temperature exposure
Solution Approach 1:
The patent employs a composite catalyst system with platinum and palladium on refractory oxide, specifically designed to withstand high temperature conditions (600-800°C). This composite structure maintains catalytic activity and structural integrity at the high temperatures required for effective regeneration, preventing catalyst degradation that would occur with conventional single-component catalysts.
Solution Approach 2:
The patent utilizes an oxidation catalyst to promote accelerated oxidation of hydrocarbon and particulates at high temperatures. This strong oxidation process efficiently combusts accumulated PM while the catalyst itself remains stable due to its composite structure, enabling sustained high-temperature operation without catalyst degradation.
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 approach enables stable, long-term filter regeneration with reduced carbon adherence, maintaining efficient combustion reactions and extending the lifespan of the purification system.
Implementation Method 1
an oxidation catalyst supported by both platinum and palladium... supplies hydrocarbon-based liquid to raise the exhaust gas temperature above 550°C for effective filter regeneration
Implementation Method 2
combustion reaction of hydrocarbon on the oxidation catalyst... raise temperature of the exhaust gas up to equal to or higher than 550°C
Implementation Method 3
prevents carbon-containing component adherence... maintaining efficient combustion reactions
Data Source
AI summary
A purification method excellent in removing particulates or the like from exhaust gas from an internal combustion engine, in particular, a diesel engine or the like. The purification method uses an exhaust gas purification apparatus including an oxidation zone installed with an oxidation catalyst supporting both platinum and palladium, and a filtering zone installed with a particulate filter, along exhaust gas flow at the exhaust gas passage of an internal combustion engine. Hydrocarbon-based liquid is supplied to the inflow side of the exhaust gas of the oxidation zone at the time when 2 to 10 g of particulates per 1 liter of the particulate filter are caught, to raise temperature of the exhaust gas up to equal to or higher than 550° C. by the oxidation catalyst so as to make the residue of the particulate filter combusted.