Exhaust Gas Treatment via Selective Cooling and Thermal Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for denitrification of exhaust gases from industrial processes, such as flue gases, face challenges in achieving efficient nitrogen oxide removal under all operating conditions, particularly in large-scale plants, due to issues like temperature imbalances, incomplete reduction, and high costs associated with catalytic processes, while secondary non-catalytic reduction methods suffer from low effectiveness and ammonia slip.
Innovation Solution
A method involving selective cooling of exhaust gases using a coolant, followed by chemical reduction with a nitrogenous reducing agent, where the temperature profile is optimized through controlled injection devices to ensure effective nitrogen oxide separation, mimicking the efficiency of catalytic reduction processes at a lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If selective catalytic reduction (SCR) is used to achieve high nitrogen oxide removal efficiency, then the nitrogen oxide separation rate is improved, but the cost and device complexity increase significantly
Solution Approach 1:
The patent replaces expensive, long-lived catalytic systems with a cheaper, non-catalytic thermal reduction approach using readily available reducing agents (ammonia or urea) that are injected and consumed in the high-temperature flue gas stream. This eliminates the need for costly catalyst materials and their associated handling infrastructure.
Solution Approach 2:
The patent utilizes the temperature parameter of flue gas (typically 850-1100°C) to enable thermal decomposition of reducing agents and subsequent reduction of nitrogen oxides. By changing the operational approach from catalytic (low temperature) to thermal (high temperature) reduction, the system achieves comparable efficiency without catalyst costs.
2Productivity
If flue gas temperature is reduced to optimize reducing agent injection, then the reduction effectiveness is improved, but the energy loss increases
Solution Approach 1:
Instead of cooling the flue gas to achieve optimal reduction conditions, the patent reverses the approach by injecting the reducing agent at high flue gas temperatures and relying on the thermal energy already present in the flue gas to drive the reduction reactions. This eliminates the energy loss associated with cooling while maintaining effective nitrogen oxide removal.
Solution Approach 2:
The patent converts the high temperature of flue gas, which was previously considered a challenge for reducing agent stability, into a beneficial parameter that drives the thermal decomposition and reduction reactions. The thermal energy that would otherwise be wasted is now utilized to enhance the reduction effectiveness.
3Productivity
If reducing agent injection is optimized for maximum nitrogen oxide removal, then the separation rate is improved, but the ammonia slip increases
Solution Approach 1:
The patent employs dynamic control of reducing agent injection based on real-time monitoring of flue gas composition and flow conditions. By continuously adjusting the injection rate and distribution, the system optimizes the reaction efficiency while preventing excess ammonia from passing through untreated, thereby reducing ammonia slip while maintaining high nitrogen oxide removal rates.
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 achieves nitrogen oxide separation rates comparable to catalytic reduction methods, reduces ammonia slip, and minimizes reducing agent consumption, while being cost-effective and flexible for retrofitting existing boilers, effectively addressing the limitations of existing denitrification technologies.
Implementation Method 1
selective cooling of the exhaust gases takes place, wherein at least one coolant is introduced into and/or brought into contact with the exhaust gas stream
Implementation Method 2
the removal and/or separation of the nitrogen oxides from the exhaust gases takes place, wherein the separation and/or removal of the nitrogen oxides from the exhaust gases is carried out by means of chemical reduction of the nitrogen oxides
Data Source
Figure 1
AI summary
The present invention relate to a method for treating exhaust gases containing nitrogen oxide from technical processes, such as fume gases, for purpose of removing or precipitating the nitrogen oxide and/or for the purpose of reducing the nitrogen oxide content, in particular by chemically reducing the nitrogen oxide.