Catalyst Regeneration Bypass Flow for Halogen Vent Gas Control
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Solution Overview
Problem
Existing catalyst regeneration processes face challenges in managing halogen loss and environmental concerns due to halogen-containing vent gases, particularly in moving bed regeneration zones, where halogen loss deactivates catalysts and venting poses environmental risks.
Innovation Solution
The process involves splitting spent catalyst into a bypass portion and an adsorption portion, where the bypass portion directly goes to the regeneration zone, bypassing the adsorption zone, while the adsorption portion handles additive adsorption, reducing halogen and moisture in the vent gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If all spent catalyst is sent through the adsorption zone before regeneration, then halogen loss is reduced, but the complexity of the process increases and productivity decreases
Solution Approach 1:
The spent catalyst stream is divided into two separate streams: one portion is sent directly to the regeneration zone while another portion passes through the adsorption zone. This segmentation allows different treatment paths for different catalyst portions, optimizing both halogen recovery and regeneration efficiency without requiring all catalyst to undergo the complete adsorption process.
Solution Approach 2:
The adsorption zone is used to extract and remove halogen from the vent gas produced during catalyst regeneration. By positioning the adsorption zone to treat only the vent gas from the bypass portion rather than all catalyst streams, the system efficiently captures halogen losses while maintaining high productivity.
2Productivity
If a bypass portion of catalyst is introduced that skips the adsorption zone, then productivity increases, but halogen loss increases
Solution Approach 1:
The adsorption zone acts as an intermediary component that treats the vent gas from the bypass catalyst stream. By introducing this intermediate treatment step specifically for the bypass portion's vent gas, the system recovers halogen that would otherwise be lost, while maintaining the high productivity benefits of the bypass configuration.
3Loss of substance
If the adsorption zone treats all vent gas from catalyst regeneration, then halogen recovery is maximized, but the volume of vent gas to be treated increases combustion products
Solution Approach 1:
The vent gas treatment is segmented so that only the vent gas from the bypass catalyst portion is sent to the adsorption zone, while the vent gas from the adsorption-processed catalyst is handled separately. This segmentation reduces the total volume of vent gas requiring adsorption treatment, thereby minimizing combustion product generation while still achieving effective halogen recovery.
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 reduces the amount of halides and combustion products in the vent gas, enhancing catalyst regeneration efficiency and minimizing environmental impact by optimizing catalyst processing and gas treatment.
Implementation Method 1
removing coke from the catalyst by burning (combustion)
Implementation Method 2
Adsorption of the halogen on the catalyst particles is advantageous
Data Source
AI summary
Processes and apparatuses for regenerating catalysts used in a hydrocarbon conversion process. The catalyst is separated into a bypass portion and an adsorption portion. The bypass portion is passed to a regeneration zone where coke may be removed. A vent gas from the regeneration zone may include an active additive from the catalyst, like a halogen. The vent gas is sent to an adsorption zone which also receives the adsorption portion. In the adsorption zone, the catalyst will contact and adsorb the active additive and then pass to the regeneration zone. The amount of active additive in the vent gas from the regeneration zone and the adsorption zone is reduced.