Flue Gas Low-Temperature Adsorption Denitrification
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Solution Overview
Problem
Current flue gas denitrification methods, such as SCR selective catalytic reduction and wet denitrification, face issues like temperature-dependent catalyst activity, high operating costs, secondary pollution, and rapid catalyst aging, as well as the need for pre-oxidation and expensive catalysts or high power consumption.
Innovation Solution
A low-temperature adsorption denitrification method that pressurizes and precools flue gas, allowing physical adsorption of NOx without catalysts or pre-oxidation, using activated carbon or molecular sieves in a thermally insulated denitrification tower, achieving NOx removal through staged cooling and recycling of condensate water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SCR selective catalytic reduction method is used to remove NOx, then NOx can be reduced to N2, but the catalyst has high activity only in a specific temperature range and operating cost is high due to ammonia escape and catalyst aging
Solution Approach 1:
The invention changes the temperature parameter of the flue gas from high temperature (suitable for SCR) to low temperature (below room temperature) through cooling systems. This parameter change enables the use of physical adsorption instead of catalytic reduction, eliminating catalyst aging issues and reducing operating costs while maintaining denitrification efficiency
Solution Approach 2:
The invention replaces the chemical catalytic reduction system (SCR) with a physical adsorption system. By using activated carbon or molecular sieves at low temperatures, the process substitutes chemical reactions with physical adsorption, eliminating the need for ammonia injection and catalyst maintenance
2Reliability
If pre-oxidation methods are used to oxidize NO to NO2, then insoluble NO can be converted to soluble NO2, but extra strong oxidants are consumed leading to high operation costs and secondary pollution
Solution Approach 1:
The invention converts the low reactivity of NO (which normally requires strong oxidants) into a benefit by using low temperature physical adsorption. The cooling process itself enables direct adsorption of both NO and NO2 without requiring pre-oxidation, turning the challenge of NO's insolubility into an opportunity for a simpler process
Solution Approach 2:
The invention extracts the pre-oxidation step from the denitrification process entirely. By removing this intermediate step and directly adsorbing NOx at low temperatures, the process eliminates the need for ozone, hydrogen peroxide, or other strong oxidants, thereby preventing secondary pollution
3Reliability
If low-temperature plasma oxidation is used to oxidize NO, then NO can be converted to NO2, but power consumption is high leading to high operation costs
Solution Approach 1:
The invention replaces the energy-intensive plasma oxidation system with a passive cooling and physical adsorption system. Instead of using high-energy plasma to drive chemical reactions, the process uses cooling to enable direct physical adsorption, dramatically reducing power consumption while achieving the same denitrification goal
4Reliability
If SCR denitrification is used, then NOx can be removed, but catalyst aging and loss are very fast requiring frequent replacement
Solution Approach 1:
The invention substitutes the catalyst-based SCR system with a catalyst-free physical adsorption system. By using activated carbon or molecular sieves that work through physical adsorption rather than chemical catalysis, the process eliminates catalyst aging, sintering, and poisoning issues, enabling long-term stable operation without catalyst replacement
Solution Approach 2:
The invention uses inexpensive adsorbent materials like activated carbon that can be easily replaced or regenerated, replacing expensive precious metal catalysts. The adsorbents can be regenerated by heating or pressure swing, extending their service life significantly
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 100% NOx removal without secondary pollution, reduces operational costs, and recycles water resources, with improved denitrification efficiency by maintaining the process below room temperature and enabling the collection of NOx for valuable by-products.
Implementation Method 1
cooling the precooled flue gas to a temperature lower than room temperature by a flue gas cooling system
Implementation Method 2
performing physical adsorption denitrification in the low-temperature denitrification system
Implementation Method 3
A denitrification adsorption tower is filled with activated carbon or molecular sieves to adsorb NOx
Implementation Method 4
A denitrification adsorption tower is filled with activated carbon or molecular sieves to adsorb NOx
Implementation Method 5
precooling the flue gas that has been subjected to dust removal and desulfurization with the denitrificated flue gas
Implementation Method 6
Condensate water generated after flue gas cooling is recycled to a reclaimed water treatment system
Data Source
AI summary
The present invention discloses a flue gas low-temperature adsorption denitrification method, including: pressurizing a flue gas that has been subjected to dust removal and desulfurization, precooling the pressurized flue gas, cooling the precooled flue gas to a temperature lower than room temperature by a flue gas cooling system, flowing the flue gas at the temperature lower than room temperature into a low-temperature denitrification system, performing physical adsorption denitrification in the low-temperature denitrification system, precooling the flue gas that has been subjected to dust removal and desulfurization with the denitrificated flue gas, and flowing the heat-absorbed clean flue gas into a chimney to be discharged.