Online Denitrification Catalyst Regeneration via Dust Monitoring
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Solution Overview
Problem
Current denitrification catalyst regeneration methods are either offline, disrupting production, or online methods like US-A-2008/089822, which prioritize ammonia optimization over catalyst regeneration effectiveness, lack reliable indicators for complete regeneration, particularly failing to account for particulate salts like metal chlorides that recombine during cooling.
Innovation Solution
The process involves online thermal treatment of the denitrification catalyst using burners to increase flue gas temperature from 170°C to 380°C, monitoring downstream dust content to ensure complete regeneration, with burners active until dust levels drop below a threshold (20 mg/Nm³ or 10 mg/Nm³), allowing continuous production without stopping the fumes treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If offline regeneration methods are used, then catalyst regeneration can be performed, but production must be stopped or significantly reduced
Solution Approach 1:
The patent implements online regeneration of the denitrification catalyst while the flue gas treatment system continues to operate. The catalyst is regenerated in situ within the SCR reactor without requiring shutdown of the production line, thus maintaining continuous productivity while restoring catalyst activity through periodic thermal treatment and washing cycles
2Productivity
If online regeneration with burner heating is used, then production continuity is maintained, but regeneration effectiveness is insufficient due to ammonia optimization priority
Solution Approach 1:
The patent incorporates a feedback control system that monitors dust content in the flue gas during regeneration. The dust content measurement serves as an indicator of regeneration progress, and this feedback information is used to adjust the regeneration process parameters, ensuring complete removal of salt deposits and poison substances from the catalyst surface
Solution Approach 2:
The patent replaces the conventional ammonia-based regeneration approach with a water washing-based regeneration system. Instead of relying on ammonia reactions to volatilize deposits, the system uses water to physically wash and remove salt deposits and poison substances from the catalyst, providing more effective regeneration while maintaining production continuity
3Loss of substance
If downstream pollutant monitoring is used, then ammonia consumption is optimized, but regeneration completion cannot be reliably determined due to undetected particulate salts
Solution Approach 1:
The patent utilizes changes in the optical properties of the flue gas as an indicator of regeneration status. The dust content measurement, which detects particulate matter including metal chloride salts, provides a visible and measurable parameter that indicates when the catalyst surface is sufficiently cleaned, enabling reliable determination of regeneration completion
Solution Approach 2:
The patent introduces dust content measurement as an intermediary parameter that correlates with regeneration completion. Rather than directly measuring catalyst surface cleanliness or ammonia reaction efficiency, the system uses dust content in the flue gas as an indirect but reliable indicator that the regeneration process has successfully removed deposits and poisons from the catalyst
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 method ensures reliable and effective catalyst regeneration with continuous production, as the increase and subsequent decrease in dust content serve as a reliable indicator for completing the regeneration process, preventing recombination of poisons and ensuring the catalyst's activity is fully restored.
Implementation Method 1
thermal treatment of the catalyst by means of fumes to denitrify the crossing through the catalyst, in particular by increasing the temperature of the fumes to denitrify, by means of burners, relative to their temperature during operation under normal conditions
Implementation Method 2
the excess heat from the flue gases partially regenerates the catalyst, by volatilizing the ammonia salts which had been deposited and accumulated until then
Implementation Method 3
increase the temperature of the fumes to be denitrified, relative to their temperature observed during operation under normal conditions: the temperature of the fumes then goes from a predetermined value for normal operation... to an increased value... using one or more burners
Data Source
Figure 1
AI summary
The invention proposes to improve the regeneration of a denitrification catalyst, so that this regeneration is less disruptive to the production of denitrified fumes using this catalyst, as well as so that it is more reliable with regard to the quality of the regeneration obtained. To achieve this, the invention provides that, while fumes to be denitrified (1), which have a temperature between 170°C and 280°C, preferably between 220°C and 250°C, and in which a denitrification reagent (2) is introduced, are sent through the catalyst to be regenerated, the temperature of these fumes is raised, to a value between 240°C and 380°C, using at least one burner (401) as long as the dust content, which is continuously measured downstream of the catalyst, has not successively passed above and then below 20 mg/Nm3 dry corrected to an oxygen reference value.Thus, the regeneration process according to the invention can be carried out online and efficiently.