Effluent Gas Treatment Combustion Air Preheating
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Solution Overview
Problem
Existing treatment systems for effluent gases in semiconductor manufacturing face challenges in efficiently removing undesirable chemicals like NH3 and NF3, while also reducing combustion by-products and NOx emissions, due to premature quenching of the combustion flame and turbulence caused by secondary combustion air introduction.
Innovation Solution
A heat exchanger is used to pre-heat secondary combustion air by mixing it with exhaust gases before entering the combustion chamber, controlling oxygen depletion and turbulence, and cooling exhaust gases for safer ducting, thereby improving combustion efficiency and reducing NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If secondary combustion air is added downstream of the burner head to improve combustion, then combustion efficiency is improved, but the flame structure is disrupted and temperature is quenched prematurely
Solution Approach 1:
The patent introduces secondary combustion air through preheating channels located upstream of the burner head, allowing the air to be warmed by exhaust gases before entering the combustion zone. This preliminary action ensures that the secondary air does not cause premature quenching when mixed with the flame, while still providing the necessary oxygen for efficient combustion.
Solution Approach 2:
The patent uses exhaust gases as an intermediary medium to transfer heat to the secondary combustion air. By routing exhaust gases through preheating channels in contact with the secondary air inlet, the system transfers thermal energy from the hot exhaust to the cooler secondary air, preparing it for mixing with the flame without causing temperature quenching.
2Productivity
If secondary combustion air is added to improve combustion, then oxidation of process gases is enhanced, but turbulence increases causing particulate deposition on burner head
Solution Approach 1:
The patent performs the mixing of secondary combustion air with exhaust gases in advance, within preheating channels upstream of the burner head. This preliminary mixing occurs in a controlled environment where flow patterns can be managed to minimize turbulence, preventing particulate deposition on the burner head while still achieving the necessary oxidation of process gases.
Solution Approach 2:
The patent uses exhaust gases as an intermediary to deliver oxygen to the combustion zone while controlling flow dynamics. The exhaust gas stream acts as a carrier that introduces oxygen-rich air into the combustion chamber through preheating channels, allowing controlled mixing that enhances oxidation without generating excessive turbulence and particulate deposition.
3Object-generated harmful factors
If exhaust gas is recirculated to provide depleted oxygen air for reducing NOx, then NOx emissions are reduced, but turbulence increases causing flame disruption
Solution Approach 1:
The patent introduces depleted oxygen air through preheating channels upstream of the burner head, allowing the exhaust gas recirculation to occur before the flame zone. This preliminary introduction of oxygen-depleted air prevents direct interaction with the flame structure, maintaining flame stability while still achieving the NOx reduction benefits of exhaust gas recirculation.
Solution Approach 2:
The patent uses preheating channels as an intermediary pathway to deliver exhaust gas recirculation to the combustion zone. This intermediary structure allows controlled mixing of exhaust gases with incoming air and fuel, providing depleted oxygen air that reduces NOx emissions without causing the turbulence and flame disruption that would occur with direct recirculation into the combustion chamber.
4Loss of energy
If combustion air is preheated to improve combustion efficiency, then energy recovery is improved, but system complexity increases
Solution Approach 1:
The patent integrates multiple functions into the preheating channel structure: it serves as both a heat exchange surface for energy recovery and as a flow distribution pathway for introducing secondary combustion air and exhaust gases. By making the preheating channels multi-functional, the system achieves energy recovery without proportionally increasing device complexity.
Solution Approach 2:
The patent combines the heat exchanger function with the air introduction and exhaust gas recirculation functions into an integrated preheating channel system. Rather than separate components, the design merges thermal energy transfer with fluid delivery pathways, achieving energy recovery while simplifying the overall system architecture through functional integration.
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 solution enhances combustion efficiency, reduces particulate fouling, and lowers NOx emissions by ensuring a stable flame structure and controlled mixing of gases, while also allowing for safer and more cost-effective exhaust gas ducting.
Implementation Method 1
a heat exchanger for exchanging heat between a first fluid and a second fluid flowing through respective first and second fluid flow paths, said first fluid flow path being connected to said inlet such that said secondary combustion air flows from said inlet into said first fluid flow path and said second fluid flow path being connected to said outlet such that said exhaust gases received at said outlet flow into said second fluid flow path
Implementation Method 2
Known treatment apparatus use combustion to remove the undesirable compounds from the effluent gas stream
Data Source
AI summary
A treatment apparatus for treating an effluent gas includes a combustion chamber; a burner; an inlet for receiving secondary combustion air; an exhaust gas outlet for outputting exhaust gases from the combustion chamber; and a heat exchanger. The heat exchanger is configured to exchange heat between a first fluid and a second fluid flowing through respective first and second fluid flow paths. The first fluid flow path is connected to the inlet and the second fluid flow path is connected to the outlet such that the exhaust gases received at the outlet flow into the second fluid flow path. The heat exchanger comprises a fluid flow communication path for providing a path for flow of a portion of the exhaust gases from the second fluid into the first fluid; and at least one inlet aperture for inputting the first fluid to the combustion chamber.