Boiler Oxygen Supply Control for Combustion Stability
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Solution Overview
Problem
Boiler facilities with oxyfuel combustion systems experience unbalance in oxygen supply and exhaust gas flow rates between wind boxes, leading to unsteady combustion.
Innovation Solution
A method and apparatus that control oxygen supply and exhaust gas flow rates by adjusting oxygen amounts and flow rates based on real-time measurements, using sensors and dampers to maintain balance and stability, ensuring consistent combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If exhaust gas is circulated through the recirculation gas line to increase carbon dioxide concentration, then carbon dioxide capture efficiency is improved, but unbalance in oxygen supply amount and exhaust gas flow rate occurs between left and right wind boxes, resulting in unsteady combustion
Solution Approach 1:
The patent divides the oxygen supply control into separate left and right channels, with independent oxygen flow rate control for each wind box. This segmentation allows independent adjustment of oxygen supply to each side, preventing unbalance and maintaining combustion stability while enabling exhaust gas recirculation for carbon dioxide concentration enhancement.
Solution Approach 2:
The patent implements local quality control by measuring oxygen concentration separately in left and right recirculation gas lines and adjusting oxygen supply independently to each wind box based on local conditions. This ensures uniform oxygen distribution and stable combustion while maintaining high carbon dioxide concentration through exhaust gas recirculation.
2Stability of the object's composition
If oxygen supply amount is increased to maintain combustion stability, then combustion stability is improved, but oxygen supply unbalance between left and right wind boxes worsens
Solution Approach 1:
The patent employs feedback control by measuring actual oxygen concentrations in left and right recirculation gas lines and using these measurements to automatically adjust oxygen flow rates. This closed-loop feedback system maintains precise oxygen supply balance between both sides while ensuring stable combustion, eliminating the need for manual adjustment and preventing oxygen supply unbalance.
3Quantity of substance
If exhaust gas flow rate is increased to enhance carbon dioxide capture, then carbon dioxide concentration is improved, but exhaust gas flow rate unbalance between left and right wind boxes occurs, leading to unsteady combustion
Solution Approach 1:
The patent segments the exhaust gas recirculation system into separate left and right channels with independent flow control. By dividing the recirculation system and controlling each side independently, the patent prevents exhaust gas flow rate unbalance while maintaining high carbon dioxide concentration, thereby ensuring combustion stability.
Solution Approach 2:
The patent dynamically adjusts exhaust gas flow rates as controllable parameters in the recirculation lines. By treating exhaust gas flow rate as an adjustable parameter and controlling it independently for each wind box, the system optimizes carbon dioxide concentration while preventing flow unbalance and maintaining stable combustion.
Data Source
AI summary
An apparatus of controlling oxygen supply for a boiler having wind boxes 2a and 2b arranged on left and right of a boiler body 1 is configured to control supply balance of oxygen by adjusting oxygen supply opening degrees of the left and right oxygen distribution dampers 15a and 15b in accordance with a oxygen supply flow rate and left and right actually measured oxygen concentrations when controlling the oxygen supply amounts and to control the exhaust gas flow rates by correcting an exhaust gas flow rate set value corresponding to a boiler load demand in accordance with an oxygen concentration set value corresponding to a boiler load demand, left and right actually measured exhaust gas flow rates and left and right actually measured oxygen concentrations and adjusting left and right exhaust gas introduction opening degrees of the left and right exhaust gas introduction dampers 8a and 8b when controlling the exhaust gas flow rates.