Angled Baffle Assembly for FCC Catalyst Stripping
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Solution Overview
Problem
Conventional FCC process catalyst strippers experience reduced efficiency due to coalescence of rising gas bubbles along the underside of co-aligned baffle surfaces, leading to inadequate stripping of entrained gas from the catalyst.
Innovation Solution
The use of a baffle assembly with baffles oriented at specific angles (5° to 80° and 100° to 175°) to prevent gas coalescence, combined with curved surfaces and perforations, enhances the mixing of falling catalyst with upward flowing steam, improving stripping efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional co-aligned baffle surfaces are used in the stripper, then the structure is simple and easy to manufacture, but gas bubbles coalesce along the underside of the baffles, reducing stripping efficiency
Solution Approach 1:
The patent applies asymmetry by orienting adjacent baffles at different angles relative to the vertical axis. Specifically, baffles are arranged with angles between 10° and 70° from the vertical, with adjacent baffles having different orientations. This asymmetric configuration prevents gas bubbles from coalescing along the underside of baffles, thereby improving stripping efficiency while accepting increased structural complexity
Solution Approach 2:
The patent introduces angular orientation as an additional dimension of variation in the baffle arrangement. By specifying that adjacent baffles be oriented at different angles (10°-70° from vertical) and that baffle rows be offset axially, the design adds dimensional complexity to the otherwise simple vertical baffle structure, preventing harmful gas coalescence patterns
2Productivity
If baffles are oriented at specific angles (5° to 80° and 100° to 175°) to prevent gas coalescence, then stripping efficiency improves, but the baffle assembly becomes more complex to manufacture
Solution Approach 1:
The patent applies parameter changes by specifying precise angular orientations for baffles (5° to 80° and 100° to 175° from vertical) and axial offsets between baffle rows. These parameter specifications optimize stripping efficiency by preventing gas coalescence, though they do increase manufacturing complexity compared to simple vertical baffles
Solution Approach 2:
The patent employs curved surfaces on baffles, specifically noting that baffle surfaces can be curved rather than flat. This curvature helps disrupt gas flow patterns and prevents coalescence along the baffle underside, improving stripping efficiency while adding to manufacturing complexity
3Productivity
If a network of baffles is used to promote mixing of falling catalyst with upward flowing steam, then stripping effectiveness increases, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the baffle structure into multiple rows with axial offsets. Each row contains multiple baffles oriented at specific angles, and rows are staggered along the axial direction. This segmented arrangement promotes thorough mixing of falling catalyst with upward flowing steam while managing the complexity through modular repetition of the baffle pattern
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 increases the effectiveness of gas stripping from the catalyst, reducing hydrocarbon content on the spent catalyst and enhancing the separation process, thereby improving the overall efficiency of the fluidized catalytic cracking system.
Implementation Method 1
The network of baffles can promote mixing of the falling catalyst with the upward flowing steam
Implementation Method 2
The spent catalyst is typically stripped in the presence of steam in a catalyst stripper to separate the residual cracked hydrocarbons
Data Source
AI summary
Systems and methods for contacting solids with a fluid are provided. The system can include a first baffle having a latitudinal centerline that is in a plane defined by first and second axes, the latitudinal centerline of the first baffle being oriented at a first angle from about 5° to about 80° with respect to the second axis. The system can also include a second baffle axially offset from the first baffle along the second axis and having a latitudinal centerline in the plane that is oriented at a second angle from about 100° to about 175° with respect to the second axis and a third baffle axially adjacent to the second baffle along the second axis and having a latitudinal centerline in the plane that is oriented at a third angle from about 5° to about 80° with respect to the second axis.