Flexible Bristle Pig Cleaning Without Damaging Protective Layers
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Solution Overview
Problem
Existing methods for cleaning coke deposits from process equipment, such as steam decoking and hydraulic pig scraping, often damage the metal protective layers, and hydroblasting is time-consuming and uneconomical.
Innovation Solution
A flexible pig with a polymeric body and partially encapsulated bristles, including a metal protective layer, is used to clean coke deposits without damaging the internal surface of process equipment, utilizing a fluid force of less than 60 psig to effectively remove coke without compromising the metal protective layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steam decoking or hydraulic pig scraping is used to remove coke deposits, then the internal surfaces can be cleaned, but the metal protective layer is damaged
Solution Approach 1:
The invention changes the mechanical parameters of the cleaning tool by using a flexible polymeric body with durometer between 30-90 and bristles with specific stiffness characteristics, allowing effective coke removal while controlling the force applied to the metal protective layer
Solution Approach 2:
The cleaning tool uses composite construction with a polymeric body and bristles made of different materials (polymer, metal, or natural fibers), where each material contributes specific properties: the polymeric body provides flexibility and cushioning, while the bristles provide cleaning capability without excessive hardness that would damage the protective layer
2Strength
If hydroblasting is used to decoke the internal surfaces, then the metal protective layer is preserved, but the process becomes very time-consuming and uneconomical
Solution Approach 1:
The invention replaces the high-pressure fluid blasting system with a mechanical pigging system that uses a flexible body with bristles, achieving effective cleaning through mechanical contact while maintaining gentler forces that preserve the metal protective layer
Solution Approach 2:
The flexible polymeric body with its ability to conform to internal surfaces and flex during passage provides effective cleaning contact without the need for high-energy hydroblasting, achieving both productivity and protective layer preservation
3Loss of information
If standard external UT gauging or internal video inspection is used to evaluate internal surfaces, then equipment condition can be assessed, but the data is incomplete or semi-qualitative when coke deposits are present
Solution Approach 1:
The flexible pig with bristles performs preliminary cleaning action by removing coke deposits before the inspection process, ensuring that subsequent UT gauging or video inspection can accurately assess the metal protective layer condition without obstruction
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 flexible pig efficiently removes coke deposits while preserving the metal protective layer, reducing downtime and operational costs, and can be used to clean complex geometries within process equipment, such as furnace tubes, without damaging the internal surfaces.
Implementation Method 1
a fluid source which provides a fluid force of less than about 60 psig (413685 Pa) to an end of the flexible pig causing at least one of the plurality of bristles of the flexible pig to contact the coke deposit
Data Source
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Figure 5
AI summary
A method for cleaning a coke deposit from an internal surface of a process equipment, comprising removing at least a portion of the coke deposit from the internal surface using a flexible pig comprising a plurality of bristles, without damaging a metal protective layer of the internal surface of the process equipment. A flexible pig (100) for cleaning a coke deposit from an internal surface of a process equipment without damaging a metal protective layer of the internal surface, comprising a flexible body (110) formed of a polymeric material (130), and a plurality of bristles (120) partially encapsulated by the polymeric material of the flexible body.