Exhaust Sulfur Adsorber Regeneration With Catalyst Bypass Control
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Solution Overview
Problem
The challenge of sulfur poisoning in methane oxidation catalysts used in exhaust gas treatment systems of LNG-fueled ships is exacerbated during the regeneration process of sulfur adsorption parts, leading to reduced catalytic activity and performance degradation.
Innovation Solution
An exhaust gas treatment apparatus with a sulfur adsorption part, a catalyst part, a gas temperature switching mechanism, and a passage switching system that allows for high-temperature gas inflow during regeneration to desorb sulfur from the adsorption part, while bypassing downstream catalysts to prevent poisoning, and a control system to manage these processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature gas is supplied to the sulfur adsorption part to desorb sulfur during regeneration, then the adsorption ability of the sulfur adsorption part is restored, but sulfur poisoning of the downstream catalyst occurs
Solution Approach 1:
The exhaust passage is divided into multiple sections with independent flow control: the sulfur adsorption part, the catalyst part, and a catalyst bypass passage. This segmentation allows high-temperature gas to be directed to the sulfur adsorption part for regeneration while bypassing the catalyst part, preventing sulfur poisoning during the regeneration process.
Solution Approach 2:
The passage switching part acts as an intermediary mechanism that controls the flow path of exhaust gas. It switches between directing gas through the catalyst (normal operation) and directing gas through the bypass passage (regeneration mode), thereby mediating between the need for sulfur desorption and catalyst protection.
2Object-affected harmful factors
If the sulfur adsorption part is used continuously to adsorb sulfur, then sulfur poisoning of the catalyst is suppressed, but the adsorption ability decreases as sulfur accumulates
Solution Approach 1:
The system operates in periodic cycles: during normal operation, the sulfur adsorption part adsorbs sulfur from exhaust gas, protecting the catalyst; periodically, the system switches to regeneration mode where high-temperature gas desorbs accumulated sulfur, restoring adsorption ability. This periodic alternation maintains long-term functionality.
Solution Approach 2:
The system discards accumulated sulfur from the sulfur adsorption part through thermal desorption during regeneration, and recovers the adsorption ability of the sulfur adsorption part for continued use. The bypassed catalyst is protected during this discarding process.
3Object-affected harmful factors
If a sulfur adsorption part is added upstream of the catalyst, then sulfur poisoning is prevented, but the device complexity increases
Solution Approach 1:
The exhaust passage structure serves multiple functions: during normal operation, it allows sulfur adsorption and catalytic treatment simultaneously; during regeneration, it enables sulfur desorption while protecting the catalyst. The passage switching part and bypass passage are integrated into the existing exhaust system, making the additional components multi-functional rather than purely additive.
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 system effectively suppresses sulfur poisoning of catalysts, maintains catalytic performance, and reduces manufacturing costs by using cheaper materials in non-high-temperature sections of the exhaust gas treatment apparatus.
Implementation Method 1
a sulfur adsorption part provided in an exhaust passage in which exhaust gas discharged from an engine flows, for adsorbing a substance containing sulfur in the exhaust gas
Implementation Method 2
a catalyst part provided on a downstream side of the sulfur adsorption part in the exhaust passage, for oxidizing or reducing a predetermined substance in the exhaust gas
Implementation Method 3
performed is a regeneration process in which high-temperature gas is supplied to the sulfur adsorption part, to thereby desorb sulfur from the sulfur adsorption part
Data Source
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AI summary
An exhaust gas treatment apparatus (3) includes a sulfur adsorption part (41) which is provided in an exhaust passage (2), a catalyst part (42) which is provided on a downstream side of the sulfur adsorption part (41) in the exhaust passage (2), a gas temperature switching part (5) which is capable of switching between a normal gas inflow state in which the exhaust gas having a normal temperature flows into the sulfur adsorption part (41) and a high-temperature gas inflow state in which the exhaust gas having a temperature higher than the normal temperature flows into the sulfur adsorption part (41), a catalyst bypass passage (76) which is provided in the exhaust passage (2) and bypasses a target catalyst (422) included in the catalyst part (42), a passage switching part (6) which is capable of switching between a bypass state in which the exhaust gas flows in the catalyst bypass passage (76) and a non-bypass state in which the exhaust gas flows in the target catalyst (422), and a control part (30) which switches the passage switching part (6) from the non-bypass state to the bypass state in execution of regeneration of the sulfur adsorption part (41) by switching the gas temperature switching part (5) from the normal gas inflow state to the high-temperature gas inflow state.