Catalytic Reactor Bypass for Dehydrogenation Pressure Management
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Solution Overview
Problem
Catalytic dehydrogenation processes for producing light olefins, such as propylene from propane, frequently require costly maintenance shutdowns due to screen fouling, which leads to high differential pressure and maldistribution of flow, and existing efforts to reduce fouling or modify reactor designs have been largely unsuccessful.
Innovation Solution
Implementing a process that measures internal differential pressure in catalytic reactors and bypasses a portion of the hydrocarbon feed stream around reactors experiencing fouling, allowing the flow to be redirected to downstream reactors, thereby managing pressure increases and extending the time between maintenance shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalytic dehydrogenation process is operated continuously, then productivity is improved, but screen fouling causes differential pressure to increase leading to forced shutdowns
Solution Approach 1:
The system dynamically adjusts the number of active reactors in the series based on the differential pressure of individual reactors. When one reactor reaches its pressure limit, the system switches to use fewer reactors (e.g., from 4 to 3 or 2), allowing continuous operation by redistributing flow dynamically rather than shutting down the entire system.
Solution Approach 2:
The system changes the operational parameters by altering the configuration of reactors in series. By switching between different numbers of reactors (4, 3, 2, or 1) based on their differential pressure status, the system adapts to fouling conditions and maintains continuous operation with extended run lengths between shutdowns.
2Productivity
If screen fouling is allowed to progress, then more propylene is produced, but differential pressure increases causing flow maldistribution and shutdown
Solution Approach 1:
The system dynamically monitors differential pressure across each reactor and switches the operational configuration before severe fouling occurs. This dynamic adjustment prevents flow maldistribution by redistributing feed flow through available reactors, allowing the system to maintain ease of operation while continuing production.
Solution Approach 2:
The system uses differential pressure measurements as feedback to determine when to switch between different reactor configurations. This feedback mechanism allows the system to respond to fouling conditions in real-time, maintaining proper flow distribution by adjusting the number of active reactors based on their pressure status.
3Reliability
If maintenance shutdowns are performed frequently, then screen fouling is cleared, but production losses and execution costs increase
Solution Approach 1:
The system performs preliminary switching to alternative reactor configurations before complete fouling occurs. By proactively switching from 4 to fewer reactors when differential pressure thresholds are reached, the system prevents severe fouling that would require shutdown, thereby extending the time between maintenance events and reducing production losses.
Solution Approach 2:
The system maintains continuous propylene production by switching between different reactor configurations rather than shutting down. This continuity of useful action eliminates production losses during the transition between reactor sets, allowing the system to operate continuously with extended run lengths between maintenance shutdowns.
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 reduces the frequency of costly turnarounds by managing differential pressure and maintaining reactor efficiency, allowing for significantly longer operation periods while minimizing production losses and costs.
Implementation Method 1
catalytic dehydrogenation processes are commonly used for the production of light olefins by conversion from their corresponding paraffins
Implementation Method 2
inner and/or outer screen fouling in the reactors. The screen fouling leads to high differential pressure
Data Source
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AI summary
Processes for catalytic dehydrogenation of paraffin stream is disclosed. The process includes passing a first portion of the paraffin-containing feedstream through a select catalytic reactor in a plurality of catalytic reactors. An internal differential pressure is measured in the select catalytic reactor. A second portion of the paraffin-containing feed stream is bypassed around the select catalytic reactor when the measured internal differential pressure is above a predetermined limit of the internal differential pressure. The bypassed second portion is passed to at least one other catalytic reactor in the plurality of reactors located downstream of the select catalytic reactor being bypassed.