SOx Trap Catalyst Segmentation for SO2 Volume Utilization
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Solution Overview
Problem
The surface of SOx trap catalysts becomes blocked by sulfates, preventing SO2 from diffusing and being trapped, leading to underutilization of the catalyst's trapping volume.
Innovation Solution
Incorporating SO2 adsorption-use oxides and an SOx storage material into the SOx trap catalyst, allowing SO2 to be adsorbed without oxidation, and storing it as sulfates when the catalyst temperature exceeds a specific start temperature, facilitating the movement of SO2 towards the storage material for effective trapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SO2 is oxidized on the surface of the SOx trap catalyst and trapped in the form of sulfates on the surface part, then the SOx trap rate is restored, but the surface part of the catalyst is covered by sulfates blocking SO2 diffusion and the trapping volume cannot be sufficiently utilized
Solution Approach 1:
The catalyst is divided into two functional zones: a surface part for SOx storage and a deep part for SO2 adsorption. This segmentation allows the surface to be covered with sulfates for NOx trap rate restoration while the deep porous structure remains accessible for continuous SO2 adsorption, resolving the contradiction between surface blocking and volume utilization.
Solution Approach 2:
The invention transitions from two-dimensional surface trapping to three-dimensional volumetric trapping by utilizing the deep porous structure of the catalyst. SO2 adsorbs in the deep part of the catalyst, moving the trapping process from the surface to the interior volume, thereby utilizing the trapping volume effectively despite surface blocking.
2Reliability
If the surface part of the catalyst is covered by sulfates, then the NOx trap rate is restored, but SO2 can no longer diffuse inside the catalyst and the trapping volume cannot be sufficiently utilized
Solution Approach 1:
The catalyst structure is segmented into surface and deep regions with different functions: the surface handles NOx trapping while the deep porous region handles SO2 adsorption. This spatial segmentation allows both functions to operate simultaneously without interference, resolving the contradiction between NOx trap rate and SO2 trapping capacity.
Solution Approach 2:
The deep porous structure acts as an intermediary zone that receives SO2 from the exhaust gas and provides a large surface area for adsorption. This intermediary deep region compensates for the blocking at the external surface, maintaining SO2 trapping capacity despite surface sulfate coverage.
3Reliability
If SO2 is trapped on the surface part of the SOx trap catalyst, then the SOx trap rate is restored, but the trapping volume of the catalyst cannot be sufficiently utilized
Solution Approach 1:
The catalyst volume is segmented into surface and deep regions, assigning different trapping functions to each. The surface region traps SOx while the deep region traps SO2, allowing the total trapping volume to be sufficiently utilized by both mechanisms operating in parallel within the same catalyst structure.
Solution Approach 2:
Different regions of the catalyst are given different local qualities: the surface has high sulfate coverage for NOx/ SOx trapping, while the deep porous region has high porosity and surface area for SO2 adsorption. This local differentiation allows each region to optimize its specific trapping function, maximizing overall volume utilization.
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 the full utilization of the SOx trap catalyst's volume by allowing SO2 to be trapped as sulfates within the catalyst, rather than on its surface, thereby enhancing the catalyst's trapping efficiency.
Implementation Method 1
the SOx trap catalyst has a property of being able to adsorb SO2 contained in the exhaust gas at the SO2 adsorption-use oxides without oxidizing
Implementation Method 2
when a temperature of the SOx trap catalyst becomes higher than a start temperature of adsorbed SO2 movement where the SO2 adsorbed at the SO2 adsorption-use oxides starts to move toward the SOx storage material
Implementation Method 3
SO2 adsorbed at the SO2 adsorption-use oxides is oxidized and is stored in the form of sulfates in the SOx storage material when a temperature of the SOx trap catalyst becomes higher than a start temperature of adsorbed SO2 movement
Data Source
AI summary
An internal combustion engine in which an SOx trap catalyst (13) for trapping SOx contained in the exhaust gas contains an oxygen adsorbing and releasing material (54) which can adsorb SO2 contained in the exhaust gas and an SOx storage material (55) which can store SOx in the form of sulfates. The SO2 which is contained in the exhaust gas is chemically adsorbed at the oxygen adsorbing and releasing material (54) without being oxidized. If the temperature of the SOx trap catalyst (13) becomes higher than the start temperature of adsorbed SO2 movement, the SO2 which is chemically adsorbed at the oxygen adsorbing and releasing material (54) is oxidized and stored in the form of sulfates in the SOx storage material (55).