CO2 Sealing in Oxyfuel Boiler Recirculation Lines
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Solution Overview
Problem
During operation of an oxyfuel combustion boiler facility, negative pressures within the combustion furnace and recirculation line allow outside air to ingress through equipment gaps, lowering the concentration of recirculating carbon dioxide.
Innovation Solution
A method and facility that branch a portion of the recirculating recirculation gas to introduce carbon dioxide gas into equipment through-holes and air ingress points for sealing, preventing external air ingress and maintaining carbon dioxide concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If recirculation gas is used to seal equipment gaps, then carbon dioxide concentration is maintained, but system complexity increases
Solution Approach 1:
The recirculation gas is used for dual purposes: maintaining negative pressure in the combustion furnace and sealing equipment gaps. This multi-functional use prevents air ingress without requiring separate sealing systems, thereby maintaining CO2 concentration while avoiding additional system complexity.
Solution Approach 2:
The system uses its own recirculation gas to seal gaps and prevent air ingress, rather than introducing external sealing gases. The recirculation gas self-services the sealing function, maintaining concentration stability without external intervention or additional complexity.
2Reliability
If seals are installed on combustion furnace to prevent ash infiltration, then equipment protection is improved, but air ingress through gaps still occurs due to negative pressure
Solution Approach 1:
Recirculation gas acts as an intermediary substance that fills gaps and prevents air ingress. The positive pressure recirculation gas displaces the negative pressure environment, creating a barrier that stops harmful air infiltration while maintaining equipment protection.
Solution Approach 2:
The recirculation gas creates an inert atmosphere within the combustion furnace and equipment gaps. By maintaining positive pressure with CO2-rich recirculation gas, the system prevents oxygen-containing air from entering, effectively creating an inert environment that eliminates air ingress problems.
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
Effectively suppresses air ingress into the boiler facility, preventing the lowering of carbon dioxide concentration in recirculating exhaust gas and ensuring stable operation by using recirculated carbon dioxide for sealing and purging purposes.
Implementation Method 1
a combustion furnace, a dust collector, a recirculation line, etc. have negative pressures so that outside air may flow inside through gaps existing in the equipments
Implementation Method 2
carbon dioxide is captured through a cooler as needed
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Provided are fuel feed means 3, an air separation unit 6,air feed means 7, a combustion furnace 11 with a burner 9 for combustion, an exhaust gas line 14 for leading an exhaust gas from the combustion furnace 11 to outside of the combustion furnace 11, exhaust gas treatment means 20a and 20b included in the exhaust gas line 14, and a recirculation line 15 for circulating a portion of the exhaust gas at least exhaust gas treatment means 20a and 20b for recirculation of a portion of the exhaust gas at least dust-removed by the exhaust gas treatment means 20a and 20b to the burner. Further provided are exhaust gas capture means 18 for taking out carbon dioxide gas from a remaining non-recirculating exhaust gas, and carbon dioxide gas feed means 33, 40 and 46 for introducing carbon dioxide gas to equipments 10, 20a and 20b of the oxyfuel combustion boiler facility.