Combustion Control via Relative Heat Release Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current combustion control methods in process fired heaters face challenges due to variations in fuel heating value, leading to inefficient operation, increased emissions, and product variability, as they rely on empirical air-to-fuel curves and PID control, which struggle to manage complex interactions and compensate for varying fuel energy content.
Innovation Solution
Implementing a control strategy that calculates a relative heat release value and determines fuel demand based on actual fuel flow, using a cross-limiting approach to adjust airflow and fuel flow, and integrating Model Predictive Control (MPC) to stabilize product temperature and reduce excess air, thereby optimizing combustion efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If empirical air-to-fuel curves and PID control are used, then the control system is simple to implement, but it cannot compensate for varying fuel energy content leading to product variability and inefficient operation
Solution Approach 1:
The patent implements a feedback mechanism where the actual fuel flow is measured and fed back to the control system. The controller uses this feedback to calculate the relative heat release value and dynamically adjust the air-to-fuel ratio, enabling the system to adapt to varying fuel energy content while maintaining manageable complexity through automated closed-loop control
Solution Approach 2:
The control system dynamically changes the parameter of air-to-fuel ratio based on the calculated relative heat release value. By continuously adjusting this parameter in response to fuel flow variations, the system achieves adaptability to different fuel energy contents without requiring complex manual intervention or multiple fixed control curves
2Reliability
If excess air is used to ensure complete combustion, then combustion safety is improved, but operational efficiency decreases and emissions increase
Solution Approach 1:
The patent transitions from static excess air margins to dynamic air-to-fuel ratio control. The system continuously calculates the relative heat release value based on actual fuel flow and adjusts the air supply dynamically, allowing the combustion process to maintain safety while minimizing excess air, thereby improving operational efficiency and reducing emissions
Solution Approach 2:
The control system uses real-time measurements of actual fuel flow to self-adjust the air supply requirements. By calculating the relative heat release value from the measured fuel flow, the system determines the precise air demand without requiring external manual intervention or conservative fixed margins, achieving both safety and efficiency
3Ease of operation
If fixed air-to-fuel ratios are used, then the control system is easy to operate, but it cannot handle variations in fuel heating value leading to incomplete or variable combustion
Solution Approach 1:
The patent replaces manual control mechanisms with an automated control system that electronically measures actual fuel flow and calculates relative heat release values. This substitution of mechanical/manual adjustment with electronic sensing and computational control maintains ease of operation while achieving precise combustion consistency through real-time adaptation to fuel variations
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 ensures consistent product temperature, minimizes excess air, reduces emissions, and enhances operational efficiency by dynamically adjusting to variations in fuel energy content, allowing for the use of waste fuels with variable heating values and improving throughput in process fired heaters.
Implementation Method 1
monitoring an actual flow of fuel into a combustion process
Implementation Method 2
calculating a relative heat release value corresponding to the fuel in the combustion process
Implementation Method 3
combustion processes, such as those used in process fired heaters, boilers, and the like, are used extensively throughout multiple industries for heating, vaporizing, or thermal cracking of various process fluids
Data Source
AI summary
Example methods and apparatus to control combustion process systems are disclosed. An example method includes monitoring an actual flow of fuel into a combustion process, calculating a relative heat release value corresponding to the fuel in the combustion process, and determining a fuel demand for the combustion process based on the relative heat release value.