Coke Removal in Vertical Riser Using Centralized Hydroblasting
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Solution Overview
Problem
The buildup of coke in vertical risers of fluid catalytic converters poses a challenge for cleaning, as high-pressure hydroblasting can damage the refractory walls and feed nozzles, and existing methods are ineffective when the coke blockage is severe, making it dangerous for personnel to intervene.
Innovation Solution
A centralizer body with radially-extending guide arms and an elongated stem equipped with angled nozzles is used to create a drainage orifice, allowing for controlled high-pressure water jetting to clear blockages while minimizing risk to the refractory walls, with adjustable configurations to accommodate varying coke buildup heights and angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-pressure water (40,000 psi) is used to remove coke build-up, then the coke removal effectiveness is improved, but the risk of damaging the refractory walls and feed nozzles increases
Solution Approach 1:
The patent applies different water pressures to different locations: high pressure (40,000 psi) is used locally at the coke build-up areas for effective removal, while lower pressure is used when cleaning the refractory walls and feed nozzles to prevent damage. This localized quality adjustment resolves the contradiction between removal effectiveness and damage prevention.
Solution Approach 2:
The cleaning process is segmented into distinct phases: first creating a drainage orifice with high-pressure jets, then evacuating water and debris, and finally cleaning the walls and nozzles with reduced pressure. This segmentation allows optimal pressure application at each stage, maintaining productivity while reducing harmful effects.
2Ease of operation
If personnel are introduced into the riser for manual hydroblasting, then the cleaning accessibility is improved, but the safety risk increases when coke blockage is severe
Solution Approach 1:
The system creates its own drainage capability by using high-pressure water jets to bore a drainage orifice through the coke obstruction. This self-service approach allows the system to evacuate water and debris autonomously through the created orifice, eliminating the need for personnel intervention in dangerous blocked conditions while maintaining cleaning effectiveness.
Solution Approach 2:
Before personnel would need to intervene, the system performs preliminary action by creating the drainage orifice and establishing water evacuation capability. This preliminary action removes the hazard of water accumulation, making subsequent cleaning operations safer and reducing the need for personnel entry into blocked risers.
3Measurement precision
If the stem is made sufficiently long to reach the obstruction, then the nozzle positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
The stem is designed as a modular, extendable structure that can be adjusted in length and configuration. This dynamic design allows the stem to be extended to the precise length needed to position nozzles accurately at the obstruction while maintaining manageable device complexity through modular construction that can be assembled and disassembled as needed.
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 method effectively clears coke blockages without damaging the riser or feed nozzles, allowing for safe evacuation of debris and subsequent thorough cleaning of the riser walls, reducing the risk of refractory damage and ensuring consistent operation.
Implementation Method 1
The nozzles are fed to produce water jets at 40,000 psi in a narrow angled cone well away from the walls of the riser. The objective of this first stage is to blast away a small diameter orifice in the obstruction
Implementation Method 2
The guide arms are in contact with the inside wall of the riser. As a result, the centralizer body and the nozzles are substantially centered along the longitudinal axis of the riser
Data Source
AI summary
A method of removing an obstruction of coke built up in a riser of a fluid catalytic converter and of cleaning the riser involves using a suspended centralizer and narrowly angled nozzles for first hydroblasting a drainage orifice in the obstruction, adjusting guide arms and manipulating the suspended apparatus to allow enlargement of the orifice, further adjusting the guide arms and enlarging the angles of the nozzles to work the remaining coke built up.