SCR Catalyst Sulfur Regeneration Using Reductant Fluid
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Solution Overview
Problem
Existing exhaust aftertreatment systems, particularly those using selective catalytic reduction (SCR) catalysts, are impaired by sulfur poisoning, which requires high temperatures for regeneration, leading to reduced efficiency and increased costs, as well as potential damage to catalysts and other components.
Innovation Solution
A system and method that uses a fluid stream with a reductant, such as urea or hydrocarbons, at controlled temperatures between 300-700°C to regenerate the SCR catalyst, allowing for sulfur removal without the need for extreme high temperatures, and includes a controller to determine sulfur levels and manage the regeneration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperatures are used to remove sulfur from the SCR catalyst, then sulfur removal effectiveness is improved, but fuel economy deteriorates and other exhaust aftertreatment components experience increased aging
Solution Approach 1:
The patent changes the chemical parameters of the treatment fluid by introducing reductants (urea, ammonia, or hydrocarbons) to enable sulfur removal at lower temperatures (300-700°C) rather than requiring extreme high temperatures, thus improving fuel economy while maintaining sulfur removal effectiveness
Solution Approach 2:
The patent introduces a reductant as an intermediary substance that facilitates the sulfur removal process at lower temperatures. The reductant acts as a mediator between the sulfur compounds and the catalyst, enabling regeneration without the need for extreme thermal conditions that would harm other components
2Reliability
If high temperatures are used to remove sulfur from the SCR catalyst, then sulfur removal effectiveness is improved, but the service life of the catalyst and other components deteriorates
Solution Approach 1:
The patent modifies the temperature parameter from extreme high temperatures to a moderate range (300-700°C) by introducing reductants, thereby preserving the catalyst and other components from thermal degradation while still achieving effective sulfur removal
Solution Approach 2:
The reductant serves as a protective intermediary that enables sulfur removal through chemical reduction rather than thermal decomposition, preventing the catalyst and other components from experiencing the damaging effects of extreme high temperatures
3Reliability
If the SCR catalyst is exposed to sulfur compounds over time, then the catalyst effectiveness decreases, but periodic removal of sulfur compounds requires high temperature treatments
Solution Approach 1:
The patent enables the catalyst to self-regenerate by introducing reductants that can be delivered through the existing exhaust aftertreatment system, eliminating the need for complex external high-temperature regeneration equipment and procedures
Solution Approach 2:
The patent changes the regeneration approach from high-temperature thermal processing to moderate-temperature chemical reduction using reductants, simplifying the regeneration process and allowing it to be integrated into normal exhaust aftertreatment operations
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 effectively regenerates the SCR catalyst, restoring its NOx conversion efficiency while reducing the stress and costs associated with high-temperature treatments, allowing for in-use sulfur regeneration and improved catalyst service life.
Implementation Method 1
providing a fluid stream having a reductant amount and a temperature, the temperature being between 300-700° C. inclusive and the reductant amount comprising an amount of urea, ammonia, or hydrocarbons
Implementation Method 2
providing a fluid stream having a reductant amount and a temperature, the temperature being between 300-700° C. inclusive
Data Source
AI summary
System, apparatus, and methods are disclosed for treating a reduction catalyst that has been exposed to an amount of sulfur. The treating of the reduction catalyst includes providing a fluid stream at a position upstream of the reduction catalyst. The fluid stream includes a temperature and a reductant amount, and the reductant amount includes an amount of urea, ammonia, or hydrocarbons.