Combustion Gas Recycling Loop for Oxy-Combustion Temperature Control
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Solution Overview
Problem
Existing combustion systems face challenges in controlling combustion temperature and oxygen concentration during oxy-combustion with recycling, leading to uncontrolled high temperatures and potential halts in combustion, especially during start-up and shut-down phases, and lack automatic adaptation to molecular oxygen deficiencies.
Innovation Solution
A combustion system with a control unit managing a recycling loop, bypasses, and valves to switch between conventional and oxy-combustion modes, using molecular-oxygen-rich gas and air to maintain stable combustion, with automatic adjustments to oxygen concentration and temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If oxy-combustion with recycling of combustion gas is implemented, then CO2 capture is facilitated and pollutant emissions are reduced, but combustion temperature becomes difficult to control and may become excessively high
Solution Approach 1:
The system implements a feedback control mechanism where combustion gas is recycled back to the combustion chamber inlet. This recycled gas acts as a cooling agent that automatically responds to temperature increases, forming a negative feedback loop that stabilizes combustion temperature while maintaining the benefits of oxy-combustion for CO2 capture and pollutant reduction.
Solution Approach 2:
The system changes the composition parameter of the oxidizing gas by adding recycled combustion gas (containing CO2 and H2O) to the molecular oxygen stream. This parameter change modifies the thermal properties of the oxidizing gas, reducing its oxygen concentration and thereby controlling the combustion temperature to remain within safe limits while preserving CO2 capture efficiency.
2Power
If molecular oxygen supply is increased to maintain combustion, then combustion intensity is improved, but risk of uncontrolled high temperature increases
Solution Approach 1:
The recycling loop provides continuous feedback control where excess heat from high-intensity combustion is automatically dissipated by recirculating combustion products back to the combustion zone. This creates a self-regulating system that maintains combustion intensity while preventing temperature runaway through passive thermal feedback.
Solution Approach 2:
The recycled combustion gas acts as an intermediary substance between the fuel and molecular oxygen. Instead of allowing direct high-temperature reaction between fuel and pure O2, the recycled gas (containing CO2 and H2O) serves as a thermal buffer that mediates the energy transfer, reducing peak temperatures while maintaining combustion power output.
3Temperature
If combustion gas recycling is implemented, then temperature control is improved, but system complexity increases due to additional valves and control mechanisms
Solution Approach 1:
The recycling loop serves multiple functions simultaneously: it cools the combustion chamber, controls temperature, facilitates CO2 capture by maintaining appropriate gas composition, and provides feedback control. This multi-functionality reduces the need for separate temperature control devices, thereby limiting the increase in system complexity despite the added recycling infrastructure.
Solution Approach 2:
The system merges the temperature control function with the existing combustion gas handling infrastructure. By combining the cooling function with the CO2 capture process (both achieved through gas recycling), the system avoids adding separate temperature control equipment, thus minimizing the increase in device complexity while achieving effective temperature management.
4Reliability
If automatic control of oxygen supply and recycling is implemented, then combustion stability is improved, but control system complexity increases
Solution Approach 1:
The automatic control system uses feedback from combustion chamber conditions (temperature, oxygen concentration) to dynamically adjust the recycling valve and molecular oxygen supply valve. This feedback mechanism improves combustion stability by automatically compensating for disturbances while using a relatively simple control architecture that monitors key parameters and adjusts valve positions accordingly.
Solution Approach 2:
The control system is designed to be self-regulating, where the recycled combustion gas itself provides the control signal through its thermal and compositional feedback to the oxygen supply and recycling valves. This self-service approach improves combustion stability without requiring complex external control systems, as the system uses its own operating conditions to automatically adjust its behavior.
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
Ensures safe and stable operation by automatically adapting to oxygen concentration changes and temperature fluctuations, preventing uncontrolled conditions and enabling seamless transitions between combustion modes without halting the process.
Implementation Method 1
remove the water vapor by condensing these combustion fumes and collecting the water in liquid form
Implementation Method 2
combustion of a fuel C by means of at least one oxidizing gas GC
Implementation Method 3
mixing air (an oxidizer) in a combustion apparatus with a fuel under high-temperature conditions to create oxidation. The reaction is exothermic
Implementation Method 4
recycling means comprising a recycling loop between the combustion device and a second inlet of the mixer
Data Source
AI summary
A combustion system including a bypass which opens to the open air during two different operating modes (“conventional combustion”; “oxy-combustion”), and which has the function, on the one hand, in the two operating modes, when the discharge valve is at least partially open and the recycling valve is closed or open, of allowing air to enter the recycling loop, and which has the function, on the other hand, in the second operating mode, when the discharge valve is closed and the recycling valve is open, of allowing a surplus of the combustion gas produced by the combustion device to be discharged from the recycling loop, the other fraction of the combustion gas produced by the combustion device supplying the mixer.