Regenerative Furnace Oxygen Concentration and Flame Control
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Solution Overview
Problem
Oxy-fuel combustion processes face high operating costs and reduced energy efficiency when using low-purity oxygen, leading to increased fuel and oxygen consumption, and adverse NOx emissions due to higher nitrogen content in the oxidant.
Innovation Solution
Controlling fuel velocities through independent adjustable flow controllers to vary flame shape and characteristics, and using an oxidant stream with 60-85 vol.% oxygen, produced by on-site air separation units, to optimize energy release and reduce refractory wall overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high purity oxygen (>90 vol.%) is used as oxidant in oxy-fuel combustion, then combustion temperature and energy efficiency are improved, but operating cost increases due to higher oxygen consumption
Solution Approach 1:
The patent changes the oxygen concentration parameter from the conventional >90 vol.% to a specific range of 60-85 vol.%, optimizing the balance between energy efficiency and oxygen consumption. This parameter optimization allows the system to achieve effective combustion while reducing oxygen demand and operating costs.
Solution Approach 2:
The patent introduces dynamically adjustable fuel velocity control through independent flow controllers for each fuel port. This allows real-time optimization of the flame profile and combustion characteristics, enabling the system to adapt to varying operational requirements and maintain energy efficiency across different operating conditions.
2Quantity of substance
If low purity oxygen (<90 vol.%) is used to reduce operating cost, then oxygen consumption decreases, but energy efficiency reduces and fuel consumption increases
Solution Approach 1:
The patent employs dynamically controllable fuel injection systems with independent flow controllers that adjust fuel velocity and distribution patterns. This dynamic control compensates for the lower oxygen concentration by optimizing fuel-oxidant mixing and combustion efficiency, maintaining energy performance despite using lower purity oxygen.
Solution Approach 2:
The patent optimizes multiple parameters including oxygen concentration (60-85 vol.%), fuel velocity, and flame profile characteristics. By coordinating these parameter changes, the system achieves cost-effective operation with reduced oxygen consumption while maintaining acceptable energy efficiency through optimized combustion dynamics.
3Temperature
If high purity oxygen is used, then combustion temperature increases, but NOx emissions increase due to higher flame temperatures
Solution Approach 1:
The patent uses dynamically adjustable fuel velocity control to shape the flame profile and distribute heat more evenly. This dynamic control prevents localized overheating and reduces peak flame temperatures, thereby suppressing NOx formation while maintaining effective combustion temperatures for process heating.
Solution Approach 2:
The patent creates different flame characteristics at different locations within the furnace by using independent fuel ports with adjustable velocities. This local optimization ensures adequate temperature distribution for heating while avoiding excessive peak temperatures that would generate NOx emissions.
4Productivity
If high velocity fuel injection is used to increase energy release rate, then productivity increases, but refractory walls overheat and service life decreases
Solution Approach 1:
The patent employs dynamically controllable fuel injection velocities through independent flow controllers for each fuel port. This allows precise control of the flame profile and heat distribution, enabling high energy release rates for productivity while preventing localized overheating of refractory walls by adjusting fuel velocity and flame shape.
Solution Approach 2:
The patent creates spatially varying flame characteristics by using multiple fuel ports with independently adjustable velocities. This local optimization distributes heat more evenly across the furnace structure, preventing concentrated thermal loading on refractory walls while maintaining high overall energy release rates for productive operation.
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
Improves energy efficiency, reduces NOx emissions, and minimizes alkali volatilization and refractory damage, while extending the service life of heat recovery devices by tailoring the flame profile and reducing peak temperatures.
Implementation Method 1
passing the oxidant through a heated regenerator to heat the oxidant
Implementation Method 2
combusting the fuel in the furnace with heated oxidant emerging from said oxidant port to produce gaseous hot products of said combustion which heat the charge
Implementation Method 3
passing combustion products through a regenerator to heat said regenerator
Data Source
Figure 1~3
Figure 2
AI summary
Disclosed is a method of operating a furnace (1) containing a charge to heat the charge, comprising wherein gaseous oxidant (15) comprising 60 vol.% to 85 vol.% oxygen is passed through a heated regenerator and into the furnace, so that the oxidant is heated to emerge from an oxidant port (20) at a temperature of 500°C to 1400°C, and gaseous fuel is fed into said furnace through two or more fuel ports (21, 22); and the heated oxidant and fuel are combusted in the furnace to produce gaseous hot products of said combustion which heat the charge; and then the flow of oxidant through the regenerator into the furnace is discontinued, and said combustion products are passed into said oxidant port and through and out of said cooled regenerator to heat said regenerator, wherein the temperature of the combustion products that pass out of said regenerator is at least 500°C; position of the fuel ports with respect to the oxidant port as well as oxidant and fuel velocities are controlled.