Ammonia Desulfurization via Segmented Absorption and pH Control
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Solution Overview
Problem
Current ammonia-based desulfurization processes struggle to effectively remove sulfur dioxide from exhaust gases while minimizing ammonia escape and aerosol formation, leading to inefficiencies and secondary pollution.
Innovation Solution
The process involves separate chambers for mixing and oxidizing ammonia-containing liquids with sulfur dioxide-containing gases, utilizing a balance hole for mass transfer and recirculating liquids to enhance ammonia utilization and reduce ammonia escape, achieving high purification efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ammonia-based desulfurization is used to remove sulfur dioxide from exhaust gases, then desulfurization efficiency is improved and waste water/slag is reduced, but ammonia escape and aerosol formation increase causing secondary pollution
Solution Approach 1:
The absorption tower is divided into multiple absorption sections (first absorption section with first spray absorption liquid, second absorption section with second spray absorption liquid) with different functional characteristics. This segmentation allows each section to optimize for specific tasks: the first section focuses on sulfur dioxide removal while the second section controls ammonia escape and aerosol formation, thereby resolving the contradiction between desulfurization efficiency and secondary pollution prevention.
2Productivity
If ammonia is used as removal agent to achieve low SO2 concentration, then desulfurization performance is improved, but ammonia loss increases
Solution Approach 1:
The patent employs parameter changes by adjusting the pH values of different spray absorption liquids to optimize the balance between SO2 removal and ammonia retention. The first spray absorption liquid operates at a higher pH (4.5-6.5) to maximize SO2 absorption, while the second spray absorption liquid operates at a lower pH (3.0-5.0) to minimize ammonia escape. This parameter differentiation resolves the contradiction by allowing each section to operate at optimal conditions for its specific function.
3Loss of substance
If recirculating spray absorption liquid is implemented to reduce ammonia loss, then ammonia utilization is improved, but system complexity increases
Solution Approach 1:
The patent merges the circulation systems of the first and second absorption sections by allowing the spray absorption liquid to flow from the first absorption section to the second absorption section, and then discharging from the second absorption section. This merged circulation approach reduces ammonia loss through continuous recirculation while avoiding the need for completely separate circulation systems, thereby limiting the increase in system complexity.
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 a high sulfur dioxide removal efficiency with minimal ammonia loss, reducing secondary pollution and operating costs, and maintaining stable operation.
Implementation Method 1
a first spray absorption liquid and a gas stream are contacted in a first spray absorption section
Implementation Method 2
removing sulfur dioxide from exhaust gases... use of separate chambers applying different forms of ammonia to remove sulfur dioxide
Implementation Method 3
an oxygen-containing gas is fed into an oxidation chamber. At least a portion of the spray absorption liquid... is fed into the oxidation chamber
Implementation Method 4
The ammonia-mixing chamber and the oxidation chamber are in fluid communication with each other through a balance hole
Implementation Method 5
at least a portion of the spray absorption liquid... is recirculated to the inlet of the first spray absorption section and/or the inlet of the second spray absorption section
Data Source
AI summary
Apparatus and methods for desulfurization of a sulfur-oxide containing gas by treatment with ammonia containing liquids. The apparatus and methods may utilize two distinct circuits of two different ammonia containing liquids which are applied in two distinct chambers. The gas may be cooled prior to entry into the circuits. There may be fluid communication between the two circulation circuits.