NH3-Atmosphere Calcination for Low-Temperature Denitrification Catalysts
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Solution Overview
Problem
Existing NOx emission control technologies, particularly in coal-dominated energy structures, face challenges in achieving high-efficiency denitration due to catalyst deactivation from excessive calcination temperatures and lack of effective calcination methods in flue gas denitration processes.
Innovation Solution
A method involving charging catalyst raw materials with oxides of V, Mo, W, Ce, Fe, Co, Ni, Cu, Nb, Sn, or Mn supported by titanium-based materials into a denitration reactor, where NH3 and an inert gas are introduced, and the temperature is held between 300°C-550°C for 1-10 hours, followed by natural cooling, to enhance catalyst activity without altering the existing preparation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excessive calcination temperature is used to improve catalyst activity, then catalyst sintering occurs, but catalyst deactivation results
Solution Approach 1:
The invention changes the calcination temperature parameter from excessive high temperature to a controlled range of 300-550°C, and introduces NH3 atmosphere as a new parameter condition. This parameter optimization prevents sintering while achieving catalyst activation, resolving the contradiction between improving catalyst activity and maintaining stability.
Solution Approach 2:
The invention uses NH3 atmosphere during calcination instead of air or oxygen atmosphere. The NH3 environment prevents oxidation and sintering of the catalyst while still enabling activation, thus maintaining catalyst stability while improving activity.
2Productivity
If conventional catalyst preparation process is used, then manufacturing simplicity is maintained, but denitration efficiency is insufficient
Solution Approach 1:
The invention performs catalyst activation during the calcination step itself, which is already part of the conventional preparation process. By introducing NH3 atmosphere during this preliminary calcination step, the catalyst is pre-activated before actual use, improving denitration efficiency without adding separate activation steps.
Solution Approach 2:
The calcination step serves dual functions: traditional sintering/formation of catalyst structure and simultaneous activation through NH3 atmosphere treatment. This multi-functionality improves denitration efficiency while maintaining the simplicity of the conventional preparation process.
3Reliability
If traditional calcination atmosphere is used, then process simplicity is maintained, but catalyst activity is limited
Solution Approach 1:
The invention replaces traditional air or oxygen calcination atmosphere with NH3 atmosphere. This creates a reducing environment that prevents catalyst oxidation and promotes active phase formation, significantly improving catalyst activity while only requiring modification of the gas supply system.
Solution Approach 2:
The invention changes the calcination atmosphere from oxidative (air/oxygen) to reductive (NH3), and optimizes temperature to 300-550°C range. These parameter changes activate the catalyst through controlled chemical reactions without requiring complex additional 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 method significantly improves denitration efficiency by 20-25% across various catalyst forms, extends catalyst service life, and maintains economic benefits by enhancing activity in both low-temperature and SO2/H2O conditions.
Implementation Method 1
Calcination, as a key step in catalyst preparation, is an important factor affecting the catalyst activity. Excessive calcination temperature will cause catalyst sintering, resulting in catalyst deactivation.
Implementation Method 2
Excessive calcination temperature will cause catalyst sintering, resulting in catalyst deactivation.
Implementation Method 3
A catalyst is a core part of a NH3-SCR system, and its performance directly affects the overall denitration efficiency and stability of the system
Implementation Method 4
The temperature of the denitration reactor is controlled at 300°C-550°C, the temperature holding time is 1 h-10 h
Data Source
AI summary
A method for preparing an active catalyst for high-efficiency denitration is disclosed. The method includes: a catalyst raw material is charged into a denitration reactor, NH3 and an inert gas are introduced and then heating is performed, and the temperature is held and then natural cooling is performed, thereby obtaining the catalyst. The active catalyst can greatly improve the denitration activity in low temperature range, and can not only improve the denitration efficiency under the condition without SO2 and H2O, but also can improve the denitration efficiency under the condition with both SO2 and H2O. The service life of the catalyst is prolonged under the premise of not changing the existing catalyst preparation process, and the economic benefit is significant. The denitration efficiency of a powder catalyst can be increased by 25%, and the denitration efficiency of a honeycombed catalyst or a corrugated catalyst can be increased by 20%.