FCC Stripping Section Structural Packing Inversion
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Solution Overview
Problem
In the Fluid Catalytic Cracking (FCC) process, the inefficiency in stripping hydrocarbons from spent catalyst particles leads to increased residence time, resulting in lower product yield and requiring extensive and costly equipment installation, which prolongs downtime and reduces economic benefits.
Innovation Solution
Locating structural packing at the top of the stripping section and minimizing the use of gratings in the lower region to reduce hydrocarbon residence time and eliminate the need for extensive welding, thereby enhancing stripping efficiency and reducing installation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional stripping internals are installed in an FCC reactor, then stripping function is provided, but extensive welding to the shell is required which prolongs installation time and downtime
Solution Approach 1:
The stripping internals are divided into modular segments that can be installed separately. The structured packing is provided as discrete modular units that can be positioned and secured without extensive welding to the reactor shell, significantly reducing installation time and downtime while maintaining effective stripping function.
2Productivity
If structural packing is located at the bottom of the stripping section, then catalyst contact is improved, but hydrocarbon residence time increases resulting in lower product yield
Solution Approach 1:
The conventional arrangement is inverted by locating the structured packing at the top of the stripping section rather than at the bottom. This inversion ensures that hydrocarbons are stripped from the catalyst as they enter the stripping section and pass through the structured packing at the top, minimizing residence time and maximizing product yield while still providing effective catalyst contact.
3Productivity
If stripping section is made taller to improve stripping efficiency, then hydrocarbon removal is enhanced, but equipment installation becomes more complex and time-consuming
Solution Approach 1:
The stripping section is configured with modular structured packing units that can be installed in a taller configuration to enhance stripping efficiency. The modular nature of the packing allows for efficient installation even in extended vertical configurations, as each module can be independently positioned and secured without requiring complex welding 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 configuration minimizes hydrocarbon residence time, boosts product yield, and reduces downtime by allowing for quicker and less invasive equipment installation, thereby improving the overall efficiency and economic viability of the FCC process.
Implementation Method 1
cascade the catalyst from side to side as it moves down a stripping section and counter-currently contacts a stripping medium
Implementation Method 2
The stripping medium enters from below the lowest layer of stripping internals and continues rising upwardly through the superjacent layers of stripping internals
Implementation Method 3
The primary separation is typically followed by a secondary separation of solids from gases in cyclones
Data Source
AI summary
In an FCC apparatus and process structured packing should be located at the very top of the stripping section in an upper region. The lower region below the structural packing may be equipped with fluidization equipment such as stripping media distributors and one or more gratings. This arrangement enables stripping of entrained hydrocarbons off the incoming catalyst immediately upon entry into the stripping section allowing the entrained hydrocarbon to exit the stripping section with minimized residence time to minimize post-riser cracking. Revamp of stripping sections with tall stripping sections should conducted in this way to improve performance and reduce down-time for equipment installation.