Distal Flame Holder Combustion Control via Pilot Preheating
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Solution Overview
Problem
Existing combustion systems face challenges in maintaining stable and efficient combustion reactions, particularly in transitioning between preheating and standard operating states, due to instability issues and inefficiencies in fuel and oxidant mixing, leading to suboptimal performance and increased NOX production.
Innovation Solution
A combustion system with a distal flame holder and a controller that uses a pilot flame sensor and distal flame holder sensor to adjust parameters and transition between states, employing a continuous pilot burner and perforated flame holder to stabilize combustion reactions, reduce NOX production, and optimize fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional combustion system operates without preheating the flame holder, then the system structure is simpler and easier to operate, but the combustion reaction becomes unstable and NOX production increases
Solution Approach 1:
The patent implements preheating of the distal flame holder before introducing the main fuel stream. A pilot flame is maintained to heat the flame holder to operating temperature in advance, ensuring that when the main combustion reaction is initiated, the flame holder is already at the required temperature to maintain stable combustion. This preliminary action eliminates combustion instability and reduces NOX production without requiring complex real-time control systems during the actual combustion process.
2Speed
If the pilot flame output is increased to preheat the distal flame holder faster, then the heating speed improves, but the system consumes more energy and produces more NOX
Solution Approach 1:
The patent employs a variable output pilot burner that can dynamically adjust its fuel output based on the heating requirements. The controller modulates the pilot flame output to provide sufficient heat for preheating the distal flame holder to operating temperature, then maintains it at the minimum necessary level to sustain stable combustion. This dynamic adjustment prevents excessive energy consumption and NOX production that would occur with continuous high-output pilot burning, while still achieving rapid enough heating to maintain combustion stability.
3Power
If the distal flame holder is positioned closer to the fuel nozzles, then the combustion reaction is more intense, but the flame stability decreases and flashback occurs
Solution Approach 1:
The patent introduces a distal flame holder as an intermediary component between the fuel nozzles and the combustion reaction zone. The flame holder is positioned at an optimized distance from the fuel nozzles to receive the fuel stream and maintain a stable combustion reaction. This intermediary structure allows the combustion to occur at a controlled location, preventing flashback into the fuel nozzles while maintaining sufficient combustion intensity. The flame holder acts as a thermal and physical buffer that stabilizes the flame and prevents direct coupling between the fuel delivery system and the combustion zone.
4Reliability
If the system operates in preheating state continuously, then the distal flame holder remains at operating temperature, but the fuel efficiency decreases and energy is wasted
Solution Approach 1:
The patent implements dynamic control of the pilot flame output based on actual combustion conditions. The controller monitors parameters such as flame holder temperature, combustion stability, and NOX levels, and adjusts the pilot flame output accordingly. When the distal flame holder reaches operating temperature and stable combustion is achieved, the system transitions from high-output preheating mode to low-output maintenance mode, minimizing unnecessary energy consumption. This dynamic adjustment ensures that the system maintains combustion stability only when necessary, improving overall fuel efficiency while preventing energy waste during continuous preheating operation.
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 system achieves stable and efficient combustion with reduced NOX production, improved fuel efficiency, and the ability to maintain combustion under conditions where conventional systems would fail, by using sensors and actuators to control the combustion process and optimize fuel and oxidant mixing.
Implementation Method 1
The pilot flame is positioned to heat the distal flame holder to an operating temperature
Implementation Method 2
the distal flame holder holds a combustion reaction of a main fuel and an oxidant
Data Source
AI summary
A combustion system includes a distal flame holder, a pilot fuel distributor, a main fuel distributor, an oxidant source, an array of sensors, and a controller. The oxidant source outputs an oxidant. The pilot fuel distributor supports a pilot flame configured to preheat the distal flame holder by outputting a pilot fuel at least when the combustion system is in a preheating state. The main fuel source outputs a main fuel in the standard operating state. The distal flame holder is configured to support a combustion reaction of the main fuel and the oxidant in the standard operating state. The sensors are configured to sense parameters of the pilot flame and the distal flame holder and to output sensor signals to the controller. The controller executes software instructions that include adjusting the flow of the main fuel, the pilot fuel, and the oxidant responsive to the sensor signals.