Regenerator Segmentation for NOx Reduction and Heat Recovery
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Solution Overview
Problem
High-temperature furnaces, such as those used in glass melting, face challenges in reducing NOx emissions without compromising heat recovery efficiency, as existing methods either reduce flame temperature and thus heat recovery or require additional equipment and fuel penalties.
Innovation Solution
A method involving a heat recovery process using two regenerators in alternating cycles, where flue gas from high-temperature furnaces is cooled and then mixed with fuel for endothermic reactions to form syngas, which is recycled and combusted in the furnace, reducing NOx emissions while maintaining heat recovery efficiency without additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If combustion air preheat temperature is reduced to lower flame temperature, then NOx emissions are reduced, but heat recovery efficiency decreases
Solution Approach 1:
The regenerator is divided into two distinct zones: a first zone for cooling flue gas and a second zone for endothermic reforming reactions. This segmentation allows simultaneous heat recovery and NOx reduction without compromising overall heat recovery efficiency, as each zone performs its specific function independently.
Solution Approach 2:
The invention changes the temperature parameter profile within the regenerator by creating a controlled temperature gradient between the first zone (cooling zone) and second zone (reforming zone). This parameter change enables the system to maintain high heat recovery efficiency while achieving NOx reduction through endothermic reactions in the second zone.
2Object-generated harmful factors
If additional NOx reduction equipment is installed, then NOx emissions are reduced, but device complexity and operating costs increase
Solution Approach 1:
The regenerator is designed to perform multiple functions: heat recovery from flue gas, cooling of flue gas, and endothermic reforming for NOx reduction. By making the regenerator multi-functional, the invention eliminates the need for separate dedicated NOx reduction equipment, thereby reducing device complexity and operating costs.
Solution Approach 2:
The invention merges the heat recovery function and NOx reduction function into a single integrated regenerator system. The first zone handles heat recovery and cooling, while the second zone performs endothermic reforming, combining what would traditionally require separate equipment into one unified device.
3Loss of energy
If flue gas temperature is maintained high for heat recovery, then heat recovery efficiency is improved, but downstream equipment must operate at higher temperatures
Solution Approach 1:
The regenerator is segmented into a first zone for high-temperature heat recovery and a second zone for endothermic reforming that cools the gas. This segmentation allows the system to maintain high heat recovery efficiency in the first zone while reducing the temperature of exhaust gases through the endothermic reactions in the second zone, protecting downstream equipment.
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
This approach effectively reduces NOx emissions by up to 27% without imposing a fuel penalty, achieving efficient heat recovery and reliable NOx reduction over longer residence times, thus addressing the limitations of existing technologies.
Implementation Method 1
reacting the gaseous combustion products and the fuel in an endothermic reaction to reduce NOx in said gaseous combustion products to nitrogen and to form syngas comprising hydrogen, CO, and said nitrogen
Implementation Method 2
passing a first part of said cooled gaseous combustion products from said first regenerator, and fuel, into a heated second regenerator
Implementation Method 3
passing said syngas from the second regenerator into the furnace and combusting it in the furnace
Data Source
AI summary
Disclosed is a combustion method in which heated flue gas heats a regenerator through which a mixture of fuel and flue gas containing NOx is passed to undergo endothermic reactions that produce syngas and destroy NOx.