Secondary Nozzle Pilot Fuel Control for Gas Turbine Combustor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional gas turbine combustors face challenges in controlling fuel flow to different regions, leading to high NOx and CO emissions due to high flame temperatures, necessitating independent variable control of fuel flow to optimize combustion efficiency and reduce emissions across varying ambient and load conditions.
Innovation Solution
A gas turbine combustor design featuring a primary combustion chamber, multiple primary nozzles, a secondary combustion chamber, and a secondary nozzle with individually controlled fuel circuits, allowing independent control of fuel flow to different regions within the combustor, including a pre-mix reaction zone and a downstream combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If diffusion combustion is used with separate fuel and air entry, then combustion simplicity is maintained, but flame temperatures exceed 2149°C resulting in high NOx emissions
Solution Approach 1:
The fuel injection system is segmented into multiple independent nozzles (primary nozzles and secondary nozzles with pilot tips) that can be controlled separately. This allows different regions of the combustor to receive different fuel flow rates, enabling optimization of combustion temperatures to reduce NOx emissions while maintaining combustion efficiency.
Solution Approach 2:
Different regions of the combustor are given different combustion characteristics by independently controlling fuel flow to primary nozzles versus secondary nozzles with pilot tips. The primary nozzles provide bulk combustion while secondary nozzles with pilot tips enable precise local temperature control to minimize NOx formation in specific zones.
2Object-generated harmful factors
If independent variable control of fuel flow is implemented, then emissions optimization is achieved, but device complexity increases
Solution Approach 1:
The fuel delivery system is divided into multiple independently controllable circuits (primary fuel nozzles and secondary fuel nozzles with pilot tips), each capable of variable flow control. This segmentation enables separate optimization of fuel delivery to different combustion zones, achieving emissions reduction across full ambient and load ranges.
Solution Approach 2:
The fuel flow rates to different nozzles and pilot tips are made dynamically adjustable and independently variable. This dynamic control allows the system to adapt to varying operating conditions (ambient temperature, load) and optimize emissions in real-time by adjusting fuel distribution across different combustion regions.
3Productivity
If high flame temperatures are maintained, then combustion efficiency is improved, but NOx emissions increase due to nitrogen disassociation
Solution Approach 1:
Different regions of the combustion chamber are given different thermal environments through independent fuel flow control. Primary nozzles maintain higher temperatures for efficient combustion, while secondary nozzles with pilot tips create localized lower-temperature zones that prevent NOx formation, achieving both efficiency and emissions control simultaneously.
Solution Approach 2:
The system changes the temperature distribution parameters across different combustion zones by independently adjusting fuel flow rates. By varying fuel delivery to primary versus secondary nozzles, the system creates optimized temperature profiles that balance combustion efficiency with NOx reduction, preventing nitrogen disassociation in critical zones.
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 design enables precise control of fuel flow, minimizing NOx emissions to sub-5ppm across full ambient and load ranges, enhancing operability and reducing CO and NOx emissions through optimized combustion system tuning.
Implementation Method 1
Traditional gas turbine combustors use diffusion (i.e., non-premixed) combustion in which fuel and air enter the combustion flame zone separately and mix as they burn. The process of mixing and burning produces flame temperatures exceeding 2149 °C (3900 °F).
Implementation Method 2
Because diatomic nitrogen rapidly disassociates and oxidizes at temperatures exceeding about 1650 °C (about 3000 °F) the high temperatures of diffusion combustion result in relatively high NOx emissions.
Implementation Method 3
Because diatomic nitrogen rapidly disassociates and oxidizes at temperatures exceeding about 1650 °C (about 3000 °F) the high temperatures of diffusion combustion result in relatively high NOx emissions.
Implementation Method 4
The secondary nozzle has a plurality of individually controlled fuel circuits. A first fuel flow is conveyed to a reaction zone of the combustor. And a second fuel flow is conveyed to a downstream combustion chamber of the combustor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed herein is a fuel nozzle (36). The fuel nozzle (36) includes a first fuel introduction location, a second fuel introduction location, and fuel passages (50). The first fuel introduction location is located radially about the fuel nozzle (36) and is connected with a fuel passage (50). The second fuel introduction location is located at an end of the fuel nozzle (36) and is connected with another fuel passage (50) such that the fuel passage (50) connected to the first fuel introduction location is separate from the fuel passage (50) connected to the second fuel introduction location.