Premixed Gas Combustor With Internal Exhaust Recirculation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing industrial combustors face limitations in controlling fuel and oxidizer mixing characteristics, leading to a limited range of operating conditions and increased NOx emissions, particularly when applied to radiant tube heating systems, which can result in local heating and burnout risks.
Innovation Solution
An industrial premixed gas combustor utilizing internal exhaust gas recirculation, featuring an oxidizer supply chamber, injection block, fuel injection orifices, and an internal recirculation tube, which adjusts flame temperature and mixing characteristics through secondary recirculation of exhaust gas to improve temperature uniformity and reduce NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional combustors are used with independent direct injection or coaxial nozzle structures, then the mixing characteristics of fuel and oxidizer are determined based on operating combustion load and air ratio, but this requires a separate control device for controlling the position or injection angle of injection nozzles, increasing device complexity
Solution Approach 1:
The combustor structure itself performs the control function through its geometric design. The pre-mixing chamber with specific volume ratio (0.3-0.7), the angled injection nozzles (30-60 degrees), and the diffuser section work together to automatically achieve optimal fuel-oxidizer mixing based on the inherent flow dynamics, eliminating the need for external control devices
Solution Approach 2:
The invention changes the physical parameters of the combustion system by optimizing the pre-mixing chamber volume ratio (0.3-0.7), injection nozzle angles (30-60 degrees), and creating a diffuser section with specific expansion angles. These parameter changes enable effective mixing control without additional control mechanisms
2Adaptability or versatility
If conventional combustors are used, then the mixing characteristics are limited by operating conditions, but this results in a limited range of operating conditions and increased NOx emissions
Solution Approach 1:
The combustor is divided into distinct functional sections: a pre-mixing chamber (occupying 30-70% of total volume), an injection section with multiple angled nozzles, and a diffuser section. This segmentation allows each section to perform its specific function optimally, enabling broad operating range and low NOx emissions across different conditions
Solution Approach 2:
The invention replaces complex mechanical control systems with fluid dynamic principles. The pre-mixing chamber design and angled nozzle arrangement create natural turbulence and mixing through flow geometry alone, eliminating the need for mechanical adjustment devices and enabling versatile operation without increasing NOx emissions
3Productivity
If conventional combustors are applied to radiant tube heating systems, then heating is provided, but this can result in local heating and burnout risks due to poor temperature uniformity
Solution Approach 1:
The diffuser section is specifically designed with expansion angles (15-30 degrees) to create a velocity profile that promotes uniform flow distribution. The pre-mixing chamber geometry (0.3-0.7 volume ratio) ensures homogeneous fuel-oxidizer mixing before entry into the radiant tube, creating locally optimized conditions throughout the tube length that prevent hot spots and ensure uniform heating
Solution Approach 2:
The pre-mixing chamber performs preliminary mixing of fuel and oxidizer before they enter the combustion zone. This pre-mixing action (occupying 30-70% of combustor volume) ensures homogeneous combustion occurs throughout the radiant tube, preventing localized overheating and burnout risks while maintaining heating efficiency
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
The combustor effectively reduces NOx emissions and prevents radiant tube burnout by optimizing flame temperature and mixing, enhancing temperature uniformity and reducing local heating through internal exhaust gas recirculation and controlled flame discharge.
Implementation Method 1
an internal recirculation tube formed to be spaced apart from the outer surface of the output end of the oxidizer supply chamber at a predetermined interval and to extend toward the outlet, and recirculating exhaust gas due to combustion
Implementation Method 2
a plurality of injection channels where oxidizers are introduced from the oxidizer supply chamber and fuel and the oxidizers are mixed and injected
Implementation Method 3
a throttling portion with a gradually decreasing inner diameter in-between the oxidizer chamber and the output end
Implementation Method 4
flame is created by the injection channels
Data Source
AI summary
The present disclosure relates to relates to an industrial premixed gas combustor using internal exhaust gas recirculation and an operating method thereof. Particularly, the industrial premixed gas combustor using internal exhaust gas recirculation includes: a fuel chamber that is provided in the central part of the interior of an injection block surrounded with an output end of the oxidizer supply chamber; an injection block that has a plurality of injection channels where oxidizers are introduced from the oxidizer supply chamber 10 and fuel and the oxidizers are mixed and injected; an orifice for fuel injection that is provided in-between the fuel chamber of the injection block and each of the injection channels, and injects fuel inside the fuel chamber to the injection block; and an internal recirculation tube that is formed to be spaced apart from the outer surface of the output end of the oxidizer supply chamber at a predetermined interval and to extend toward the outlet, and recirculates exhaust gas due to combustion.