Ammonia Desulfurization Absorption Tower pH and Temperature Control
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Solution Overview
Problem
Ammonia desulfurization processes face challenges with ammonia escape and aerosol production during absorption, leading to high energy consumption, complex systems, and poor economical efficiency, as existing methods focus on capturing aerosols rather than reducing their production, and the oxidation of ammonium sulfite is inefficient due to low O2 content and temperature.
Innovation Solution
Implementing a gas purification and removal system with staged solution composition control and reaction condition control, using an absorption circulation liquid with ammonium sulfite and ammonium sulfate, and a fine particle washing circulation liquid with different pH values and concentrations to achieve synergistic control of absorption, oxidation, and concentration, reducing ammonia escape and aerosol production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ammonium sulfite and free ammonia contents are maintained at a high level in the absorption liquid to ensure absorption efficiency, then absorption efficiency is improved, but ammonia escape and aerosol production increase seriously
Solution Approach 1:
The patent changes the pH parameter of the absorption liquid from conventional high pH (7.0-8.5) to low pH (5.0-6.5), which fundamentally alters the chemical equilibrium to suppress ammonia escape and aerosol formation while maintaining high absorption efficiency through optimized ammonium sulfite concentration
Solution Approach 2:
The patent applies different concentration levels of ammonium sulfite at different locations within the absorption tower, with higher concentrations (10-20 g/L) in the lower absorption section and lower concentrations (5-15 g/L) in the upper section, optimizing both absorption efficiency and aerosol control in different zones
2Productivity
If absorption temperature is controlled at not higher than 40°C to ensure absorption efficiency, then absorption efficiency is improved, but oxidation and concentration processes become unfavorable, leading to high energy consumption and complex equipment
Solution Approach 1:
The patent raises the absorption temperature from conventional ≤40°C to 45-60°C, which accelerates the oxidation rate of ammonium sulfite to ammonium sulfate and improves evaporation efficiency during concentration, thereby reducing energy consumption and simplifying equipment while maintaining high absorption efficiency through low pH control
Solution Approach 2:
The patent enables the absorption liquid to continuously undergo oxidation and concentration within the absorption tower itself through the optimized temperature and pH conditions, eliminating the need for separate oxidation tanks and evaporation equipment,从而实现 continuous desulfurization and product recovery in one integrated system
3Productivity
If absorption temperature is reduced to not less than 40°C to pursue absorption efficiency, then absorption efficiency is improved, but water in flue gas condenses, requiring waste water discharge and increasing operation cost
Solution Approach 1:
The patent optimizes the absorption temperature to 45-60°C, which is above the dew point of flue gas, preventing condensation of water vapor and eliminating the need for waste water discharge, while maintaining high absorption efficiency through low pH (5.0-6.5) and optimized ammonium sulfite concentration
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 simplifies the technological process, reduces investment and operation costs, and achieves efficient desulfurization and dust removal while controlling ammonia escape and aerosol production, meeting stringent emission standards.
Implementation Method 1
Absorbing sulfur dioxide with ammonium sulfite to obtain a mixed solution of ammonium sulfite and ammonium bisulfite
Implementation Method 2
(NH4)2SO3+H2O+SO2═2NH4HSO3
Implementation Method 3
Supplying oxidation air to the solution to oxidize ammonium sulfite to give ammonium sulfate: (NH4)2SO3+1/2O2═(NH4)2SO4
Implementation Method 4
Subjecting the ammonium sulfate solution to concentration, crystallization, solid-liquid, separation and drying
Data Source
AI summary
Apparatus and methods for controlling aerosol production during absorption in ammonia desulfurization, by removing sulfur dioxide in flue gas with an absorption circulation liquid containing ammonium sulfite, so as to control the aerosol production during absorption in ammonia desulfurization. Efficient desulfurization and dust removal may be achieved by staged solution composition control and reaction condition control. At the same time ammonia escape and aerosol production during absorption may be controlled. The flue gas may be subjected to preliminary temperature lowering and purification, and may be allowed to contact with an absorption circulation liquid and a fine particle washing circulation liquid sequentially. Levels of solution compositions and reaction temperatures may be controlled.