Furnace Burner Temperature Uniformity via MIMO Control
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Solution Overview
Problem
Achieving and maintaining high temperature uniformity in heat treating furnaces is challenging due to the need for manual adjustments of fuel/air ratio in burners, which are time-consuming and result in cascading effects, requiring repeated certification tests to meet stringent temperature specifications.
Innovation Solution
A method involving a training phase to record temperature changes caused by burner adjustments and a tuning phase to iteratively adjust burner conditions using a MIMO control algorithm to optimize air-fuel ratios, ensuring uniform temperature distribution across the work zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual fuel/air ratio adjustment valves are used on individual burners to achieve temperature precision, then temperature uniformity in the work zone is improved, but the complexity of operation increases and time-consuming adjustments are required
Solution Approach 1:
The patent replaces manual mechanical adjustment of fuel/air ratio valves with an automated control system that uses electronic actuators and a control algorithm to adjust burner settings. The system measures temperatures at multiple locations and automatically adjusts the fuel/air ratio of individual burners to achieve uniform temperature distribution, eliminating the need for manual intervention while maintaining temperature precision.
2Manufacturing precision
If individual burner adjustments are made to achieve temperature uniformity, then temperature precision is improved, but the time required for certification and tuning increases
Solution Approach 1:
The patent performs preliminary characterization of the furnace by measuring the temperature response to unit adjustments of each burner. This data is stored and used to predict the effect of any adjustment combination on temperature uniformity. During certification, the system uses this pre-collected data to rapidly calculate and implement the optimal adjustment settings, dramatically reducing the time required compared to trial-and-error manual adjustment.
Solution Approach 2:
The system continuously monitors temperatures at multiple locations in the work zone and uses this feedback to automatically adjust the fuel/air ratio of individual burners. The control algorithm calculates the required adjustments based on measured temperature deviations from the target uniformity, iteratively converging on the optimal settings without requiring repeated manual certification tests.
3Manufacturing precision
If manual adjustment of fuel/air ratio is performed to meet temperature specifications, then temperature uniformity is improved, but the complexity of the adjustment process increases due to cascading effects
Solution Approach 1:
The patent replaces complex manual adjustment procedures with an automated control system that uses a control algorithm to calculate the optimal fuel/air ratio for each burner. The system measures temperatures at multiple locations and automatically determines the required adjustments, eliminating the need for operators to understand and manage the cascading effects of individual burner adjustments.
Solution Approach 2:
The patent introduces a control system as an intermediary between the burners and the temperature uniformity requirement. This intermediary collects temperature data from multiple sensors, calculates the optimal adjustment settings using a control algorithm, and automatically implements the adjustments. This intermediary layer simplifies the overall control process by managing the complexity of multiple interacting burners through systematic calculation rather than manual trial-and-error.
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 approach allows for precise and efficient achievement of high temperature uniformity, reducing the need for frequent re-certifications and improving the consistency of heating quality across the work zone, meeting stringent ASTM and AMS2750F Class III requirements.
Implementation Method 1
The combustion system will be comprised of a number of burners positioned high on the fired wall above the load intended for heating
Implementation Method 2
Cross-fired burners can also be located low on the wall, firing beneath the load when it is placed on piers in the furnace
Implementation Method 3
This is done by placing a three-dimensional array of thermocouples into the work zone
Data Source
AI summary
A method includes firing a first burner into a furnace process chamber in a first initial condition, firing a second burner into the process chamber in a second initial condition, and measuring temperature at each of an array of locations in the process chamber. The first burner is adjusted to a first adjusted condition while the second burner is being fired at the second initial condition, and a resulting first temperature change is measured at each of the locations. The second burner is adjusted to a second adjusted condition while the first burner is being fired at the first initial condition, and a resulting second temperature change is measured at each of the locations. The measured first and second temperature changes are recorded as reference data for adjusting burner conditions to adjust temperatures at each of the locations. The method can thus be used to improve temperature uniformity throughout the array of locations.