Adjustable Impeller Vapor Separation for Lignite Boiler Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lignite-fired boilers face challenges in maintaining safe operation and flame stability at low load conditions due to limitations in fuel concentration and pressure losses associated with existing vapor separation systems, which fail to guarantee broad operation range and safe ignition.
Innovation Solution
A combustion system with a vapor separation system that includes an impeller with adjustable blades to separate fuel flows into concentrated and reduced content streams, allowing for adjustable pitch angles to optimize separation and pressure losses based on load conditions, ensuring safe operation across a broad load range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an impeller is used to separate fuel flows, then separation effectiveness is improved, but pressure losses increase
Solution Approach 1:
The impeller blades are made adjustable in pitch angle, allowing the separation system to dynamically adapt its characteristics. By varying the blade pitch angle, the system can optimize the balance between separation effectiveness and pressure losses depending on operating conditions such as load and fuel quality.
2Reliability
If fuel concentration is increased for safe operation at low load, then operational safety is improved, but pressure losses in vapor separation systems increase
Solution Approach 1:
The system changes the operational parameters of the impeller by adjusting the blade pitch angle according to load conditions. At low load, the adjusted pitch angle optimizes separation to achieve the necessary fuel concentration for safe operation while minimizing pressure losses.
3Device complexity
If a fixed pitch angle is used, then device complexity is reduced, but adaptability to different load conditions deteriorates
Solution Approach 1:
The impeller blades are made adjustable in pitch angle, allowing the separation system to dynamically adapt its characteristics. By varying the blade pitch angle, the system can optimize the balance between separation effectiveness and pressure losses depending on operating conditions such as load and fuel quality.
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 enables safe and stable operation at low and very low loads while minimizing pressure losses, maintaining efficient operation at medium and high loads by adjusting the impeller blade pitch angles, thereby stabilizing flames and ensuring fuel concentration.
Implementation Method 1
an impeller with adjustable blades (12b) to separate the non-homogeneous flow into a fuel rich flow and a fuel lean flow; the impeller defines, through the blades (12b), a fuel concentrated content flow (FC) and a fuel reduced content flow (FR)
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The combustion system (1) comprises a furnace (2) with an enclosure (3) and burners (4a, 4b, 4c) having different elevation, a mill (6), a vapour separation system (7) for receiving a non-homogeneous flow of vapour and pulverized fuel and providing a fuel rich flow through first ducting (10) to burners (4a, 4b) having a lower elevation, and a fuel lean flow through second ducting (11) to burners (4c) having a higher elevation. The first ducting (10) comprises an impeller (12) at a position downstream the branching area (9). The impeller (12) defines a fuel concentrated content flow (FC) and a fuel reduced content flow (FR). The combustion system comprises also ducting (15) for supplying the fuel concentrated content flow (FC) to first burners (4a) and ducting (16) for supplying the fuel reduced content flow (FR) to second burners (4b). The second burners (4b) have a higher elevation than the first burners (4a).