Thermal Imaging Control of Cracking Furnace Coil Hotspots
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Solution Overview
Problem
Accurate measurement of radiant coil temperature during hydrocarbon cracking is challenging, leading to coke accumulation and potential damage from hotspots, necessitating improved control methods for decoking operations.
Innovation Solution
Implementing thermal imaging devices outside the hydrocarbon cracking furnace to measure tube metal temperature, coupled with a controller to adjust heat sources independently, optimizing heat input based on temperature measurements to prevent hotspots and enhance decoking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional temperature measurement methods are used inside the furnace, then direct temperature data can be obtained, but the measurement accuracy is insufficient and hotspots cannot be detected reliably
Solution Approach 1:
A viewing window is introduced as an intermediary component that allows infrared radiation from the radiant coil to pass through to the thermal imaging device located outside the furnace. This mediator enables accurate non-contact temperature measurement without requiring physical sensors inside the harsh furnace environment, thereby improving measurement precision while avoiding the complexity of in-situ measurement systems
Solution Approach 2:
The patent replaces traditional mechanical contact temperature sensors with a thermal imaging device that uses infrared radiation detection. This substitution eliminates the need for physical sensor installation inside the furnace, improving measurement accuracy by allowing observation of the entire coil surface simultaneously while reducing system complexity
2Productivity
If uniform heat input is applied to the radiant coil, then simple control is maintained, but coke accumulation occurs and decoking efficiency is poor
Solution Approach 1:
The control system adjusts the heat input from individual heat sources based on locally measured temperature data from different sections of the radiant coil. By applying different heat inputs to different locations according to their specific coke accumulation conditions, decoking efficiency is improved while the complexity is managed through modular control of multiple independent heat sources
Solution Approach 2:
The system uses thermal imaging data as feedback to continuously monitor the temperature distribution along the radiant coil during decoking operations. This feedback information is used to dynamically adjust the heat input from individual heat sources, optimizing decoking efficiency while maintaining controllable system complexity through automated control algorithms
3Object-generated harmful factors
If high temperature steam and air are passed through the radiant coils for decoking, then coke removal is achieved, but radiant coil hot spots develop causing potential damage
Solution Approach 1:
During decoking operations, the thermal imaging device continuously monitors the temperature distribution along the radiant coil as feedback. When hot spots are detected in real-time, the control system immediately adjusts the heat input or steam flow to those specific locations, preventing coil damage while maintaining effective coke removal in other sections
Solution Approach 2:
The system performs preliminary temperature assessment using thermal imaging before initiating high-temperature decoking. This preliminary action identifies vulnerable sections of the coil, allowing the control system to pre-adjust heat distribution or protective measures to prevent hot spot formation during the subsequent decoking process
4Area of stationary object
If multiple thermal imaging devices are distributed along the radiant coil path, then comprehensive temperature coverage is achieved, but device complexity and cost increase
Solution Approach 1:
Instead of placing multiple thermal imaging devices at different locations along the coil path, the patent positions a single thermal imaging device to capture the entire coil in a two-dimensional field of view through the viewing window. This dimensional approach achieves comprehensive temperature coverage while minimizing system complexity by using one device rather than multiple distributed sensors
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
Enhances decoking operations by precisely controlling heat distribution, reducing coke accumulation, and preventing radiant coil damage while maintaining optimal cracking conditions.
Implementation Method 1
A thermal imaging device is arranged outside of the heating compartment, and the thermal imaging device has a field of view encompassing at least a portion of the radiant coil. The thermal imaging device is operable to measure a tube metal temperature of the portion of the radiant coil in the field of view.
Data Source
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AI summary
A system for automatically controlling an operation of a hydrocarbon cracking furnace using radiant coil tube metal temperature measurement data obtained from one or more thermal imaging devices is disclosed. The tube metal temperature measurement data generated by the thermal imaging devices may be provided to a controller that may also be in communication with one or more heat sources used to heat the radiant coils. When multiple heat sources are present, the controller can independently control the heat output of each heat source based on the received tube metal temperature measurement data, which can allow the temperature at different locations along the radiant coils to be varied. In one example, the temperature at different locations along the radiant coils can be varied during a decoking operation in correlation with varying degrees of coke accumulation within the radiant coils.