Hot Gas Stream Denitrification for Entrained-Flow Plants
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing denitrification methods for entrained flow treatment systems require high exhaust gas temperatures for efficient nitrogen oxide reduction, leading to energy loss and challenges in further utilizing the thermal energy, especially when catalysts are not used.
Innovation Solution
Introducing a reducing agent, such as ammonia, into the hot gas stream immediately after the hot gas generator before the temperature falls below 700°C, allowing for selective non-catalytic reduction of nitrogen oxides without catalysts, and optionally using additional thermal energy to maintain optimal temperature ranges for denitrification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If selective non-catalytic reduction (SNCR) is used without a catalyst, then costs are reduced, but exhaust gas temperature must be lowered to around 900°C which causes significant energy loss
Solution Approach 1:
The patent introduces the reducing agent into the hot gas stream before it enters the treatment chamber, performing the denitrification action in advance. This preliminary action allows the reduction to occur at higher temperatures where the hot gas naturally exists, avoiding the need to cool the exhaust gas to 900°C and thereby preventing energy loss while still achieving effective denitrification without catalysts
Solution Approach 2:
The patent converts the previously harmful hot gas stream (which caused energy loss when cooled for SNCR) into a beneficial medium for denitrification. By utilizing the high temperature of the hot gas stream before it enters the treatment chamber, the system transforms what was a waste energy carrier into an effective reaction medium that enables catalyst-free reduction without energy penalty
2Ease of manufacture
If reducing agent is introduced into exhaust gas after material treatment, then denitrification can occur, but the hot gas has already cooled and temperature drop reduces reduction efficiency
Solution Approach 1:
The reducing agent is introduced into the hot gas stream before the gas enters the treatment chamber, performing the denitrification action in advance. This preliminary action ensures that the reduction occurs when the gas temperature is still high, maintaining reduction efficiency while simplifying the overall process by eliminating post-treatment steps
3Productivity
If exhaust gas temperature is maintained high for thermal treatment, then material treatment efficiency is improved, but energy loss increases when subsequent cooling is required for denitrification
Solution Approach 1:
The patent converts the hot gas stream, which represents thermal energy that would otherwise be wasted, into a beneficial reaction medium for denitrification. By introducing the reducing agent into this hot gas before it enters the treatment chamber, the system utilizes the existing high temperature to drive the reduction reaction, thereby converting what would be energy loss into a productive denitrification process without compromising material treatment 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
This method achieves efficient nitrogen oxide reduction in the hot gas stream before it mixes with the material, reducing energy loss and allowing for effective denitrification without catalysts, while maintaining high reduction efficiency and minimizing temperature drops.
Implementation Method 1
Introducing a reducing agent, such as ammonia, into the hot gas stream immediately after the hot gas generator before the temperature falls below 700°C, allowing for selective non-catalytic reduction of nitrogen oxides without catalysts
Implementation Method 2
a material is thermally treated, the heat energy used for this purpose being provided at least partially by a hot gas generator
Data Source
Figure 1
Figure 2
AI summary
Disclosed is a method for reducing nitrogen oxides in the exhaust gas of an entrained-flow treatment plant in which a material is subjected to a thermal treatment; at least some of the thermal energy used for said treatment is supplied by a hot gas generator (3). The disclosed method is characterized in that a reducing agent is admixed to the hot gas from the hot gas generator (3) before the temperature of the hot gas drops to 700°C or less, preferably 850°C or less.