Dynamic Water-Fuel Ratio Control for Combustion Pulsation
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Solution Overview
Problem
Current combustion technologies struggle to maintain optimal NOx emissions and pulsation levels, especially during the warming up phase and under varying ambient conditions, leading to potential exceedance of legal limits and triggering of protective events.
Innovation Solution
A method and apparatus for dynamically adjusting the water-to-fuel ratio (ω) in a combustion device using a controller to detect and respond to flame-generated pulsations, reducing ω when pulsations exceed a threshold and increasing it gradually as a linear function of time to maintain optimal pulsation and NOx levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If water injection is used to lower NOx emissions by maintaining a fixed ω value, then NOx emissions are reduced, but pulsation levels increase and may trigger protective events
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed ω value to a dynamically adjustable ω value that responds to real-time combustion conditions. The control system continuously monitors combustion pulsations and adjusts the water-to-fuel ratio accordingly, allowing the system to adapt to changing operating conditions while maintaining both low NOx emissions and stable combustion.
Solution Approach 2:
The patent implements feedback control by using combustion pulsation signals as feedback to adjust the water injection rate. The control system measures pulsation levels and uses this information to modify the ω value, creating a closed-loop control system that automatically maintains optimal combustion conditions.
2Stability of the object's composition
If ω is increased to reduce pulsations, then combustion stability improves, but NOx emissions increase above legal limits
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the ω parameter based on real-time combustion conditions. Rather than using a fixed or simply increased ω value, the system modifies this parameter continuously according to measured pulsation levels, allowing optimal balance between stability and emissions control.
3Device complexity
If a single fixed ω value is used during warm-up, then control logic is simple, but NOx emissions exceed legal limits and pulsations remain high
Solution Approach 1:
The patent applies dynamics by implementing a control system that adapts ω values according to the engine's thermal state and operating conditions. During warm-up and at different load levels, the system automatically adjusts the water-to-fuel ratio, providing optimal emissions control without requiring complex manual intervention or multiple fixed control modes.
4Speed
If water injection rate is rapidly adjusted to control pulsations, then pulsation response time decreases, but combustion instability may increase during adjustment
Solution Approach 1:
The patent applies periodic action through continuous monitoring and incremental adjustment of the water injection rate. Rather than making single large changes, the system continuously adapts the ω value in response to ongoing pulsation measurements, providing smooth control that responds quickly to pulsations while maintaining combustion stability during transitions.
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 that NOx emissions remain below legal limits and pulsation levels are kept within acceptable ranges, avoiding protective load shedding and adjusting to different ambient conditions, thereby optimizing combustion behavior throughout the engine's operation.
Implementation Method 1
a water injection system configured to mix water to fuel in the combustion chamber and to adjust a parameter ω defined as a ratio between water and fuel
Implementation Method 2
a controller for detecting flame-generated pulsations above a predefined threshold
Implementation Method 3
an indispensable requisite for achieving an efficient combustion process
Data Source
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AI summary
The present invention generally relates to the field of combustion technology related to gas turbines. More in particular, the present invention refers to a method for operating a combustion device. Advantageously, by means of the invention a pulsation protective load shedding (PLS) is avoided by adjusting the parameter ω (water/oil ratio) in case of too high combustion pulsation levels from the standard operation set point. This implies that the dynamic pulsation control logic (P.C.L.) is activated in case the high frequency pulsation level exceeds a predetermined threshold value and a control unit adjusts the ω, preferably in a stepwise manner, until acceptable and optimum pulsation levels are reached or a maximum reduction of the ω is performed