Solid Fuel Firing Unit Regulation via Flue Gas Moisture
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Solution Overview
Problem
Existing solid fuel firing systems face challenges in maintaining optimal combustion quality due to fluctuating water content in fuels, leading to unstable combustion conditions, slag formation, and insufficient combustion, especially when multiple fuels are used simultaneously.
Innovation Solution
A control system that automatically adjusts primary air and primary flue gas recirculation based on the water content of the flue gas, eliminating the need for manual intervention or precise fuel water content measurement, by using a measuring device connected to control the air fans, and an auxiliary burner for support when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual regulation of air supply and support burner is used, then device complexity is reduced, but combustion quality becomes unstable due to long reaction times
Solution Approach 1:
The control system continuously measures flue gas water content and uses this feedback to automatically adjust primary air supply and primary flue gas recirculation rates, eliminating the long reaction times associated with manual regulation and maintaining stable combustion conditions
Solution Approach 2:
The patent replaces manual mechanical regulation with an automated control system that uses electronic sensors to measure water content and electronically controlled actuators to adjust air supplies, thereby improving response time and combustion stability
2Manufacturing precision
If precise measurement of fuel water content is implemented, then combustion quality can be optimized, but measurement effort and system complexity increase unreasonably
Solution Approach 1:
Instead of directly measuring fuel water content, the system uses flue gas water content as an intermediary parameter that reflects fuel moisture conditions, thereby achieving combustion optimization without the complexity of direct fuel measurement
Solution Approach 2:
The control system automatically measures and adjusts parameters based on flue gas analysis, eliminating the need for manual fuel sampling and measurement while maintaining precise combustion control
3Reliability
If primary air volume is increased to handle high water content fuel, then combustion stability improves, but energy efficiency decreases due to excess air
Solution Approach 1:
The control system dynamically adjusts primary air supply and primary flue gas recirculation rates based on real-time flue gas water content measurements, allowing the system to optimize the balance between combustion stability and energy efficiency for each operating condition rather than using fixed high air rates
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 solution ensures consistent combustion quality over time by dynamically adjusting air supply and recirculation, preventing slag formation and maintaining stable temperatures, even with varying fuel compositions.
Implementation Method 1
a measuring device for measuring the water content of the flue gas
Implementation Method 2
connected via a control device to a primary air fan and to a fan for primary flue gas recirculation
Implementation Method 3
The combustion of completely dry wood would lead to a water content in the flue gas of around 5.3%
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a method for regulating a solid fuel firing unit, at least comprising a primary air supply (5) and a primary flue gas recirculation device (6). The invention is characterised in that the nominal values for the quantity of primary air and air from the primary flue gas recirculation device is adjusted depending on the water content of the flue gas. This guarantees the availability of a continuous, automatic regulation of a solid fuel firing unit that permits the most uniform combustion quality possible over a long period of time.