FCC Unit Corrosion-Resistant Coating Anchoring Process
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Solution Overview
Problem
Corrosion-resistant coatings in fluid catalytic cracking (FCC) units face degradation due to erosion and corrosion, particularly at the junctions of the anchoring structure and metal walls, leading to coke formation and detachment, which existing solutions fail to adequately address.
Innovation Solution
A process involving a metal anchoring structure with fastening tabs that are welded to the metal wall, allowing the composite material to fill the space between the tabs and the wall, thereby reducing gas penetration and corrosion, while maintaining flexibility and expansion compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anchoring structure is welded to the metal wall, then the coating provides erosion protection, but gas penetrates through interstices and causes corrosion and coke formation at the welds
Solution Approach 1:
The anchoring structure is divided into multiple discrete weld points distributed across the metal wall, rather than continuous welding. This segmentation allows gas to be blocked at multiple locations while preventing concentrated corrosion at single weld points, thereby maintaining coating protection while reducing gas penetration effects.
Solution Approach 2:
The welding is performed only at specific localized points on the metal wall rather than across the entire surface. This local quality approach provides sufficient anchoring strength at the weld points while leaving other areas open to prevent gas penetration pathways, thus balancing protection with corrosion resistance.
2Stability of the object's composition
If the composite material fills the cells of the anchoring structure, then the coating absorbs expansion differences, but the gaps between composite material and anchoring structure allow coke formation
Solution Approach 1:
The anchoring structure is pre-formed with a configuration that creates controlled gaps between the composite material and the metal wall. These pre-designed gaps are positioned to allow expansion difference absorption while being arranged to prevent coke accumulation, thus addressing both requirements simultaneously.
3Area of stationary object
If the strips of the anchoring structure are assembled in pairs, then the coating provides comprehensive coverage, but the junctions of the strips create pathways for gas penetration
Solution Approach 1:
The strips of the anchoring structure are designed with asymmetric junction configurations where the meeting points of adjacent strips are positioned to minimize gas penetration pathways. This asymmetric arrangement maintains comprehensive coverage while creating less favorable conditions for gas accumulation at the strip junctions.
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
The solution effectively prevents gas penetration and corrosion, extending the lifespan of the coating and reducing maintenance needs by enhancing the resistance to degradation and coke formation, while simplifying the welding process.
Implementation Method 1
the free edge of at least some of the fastening tabs being welded to the metal wall
Data Source
AI summary
The invention relates to a process for the positioning of a corrosion-resistant coating on an internal or external metal wall (20) of a fluid catalytic cracking unit chamber, comprising:(i) the shaping of a metal anchoring structure (10) formed from a plurality of strips (12) assembled in pairs by joining assembly portions (121, 122) so as to form a plurality of cells (14), the anchoring structure comprising a plurality of fastening tabs (16) integral with strip portions other than assembly portions,(ii) the fastening of said anchoring structure (10) by welding the free edge (18) of a part at least of the fastening tabs to the metal wall (20), defining a space between a longitudinal edge (12b) of an anchoring structure and the metal wall,(iii) the insertion of a composite material into the cells (14) from the metal wall (20) and at least up to the upper longitudinal edge (12a) of each strip.