Dual Alkali Flue Gas Desulfurization for Industrial Boiler SO2 Removal
Product Details
Dual Alkali Flue Gas Desulfurization for Industrial Boiler SO2 Removal
Technology Principle
The calcium-sodium dual alkali process first uses a sodium-based alkaline absorbent solution for flue gas desulfurization. The sodium-based absorbent, typically sodium hydroxide (NaOH) or sodium carbonate (Na₂CO₃), reacts with sulfur dioxide in the flue gas. After the absorption step, the spent solution is regenerated using lime (calcium hydroxide). The regeneration step converts the sodium sulfite back to sodium hydroxide while precipitating calcium sulfite.
Because the entire reaction process occurs between liquid and gas phases, the system avoids the scaling problems common in traditional lime-gypsum processes. The dual alkali process offers several additional advantages: high absorption rate, low liquid-to-gas ratio, high absorbent utilization, lower capital investment, and reduced operating costs.
Technical Characteristics
Reduced Corrosion and Fouling
Using NaOH (or Na₂CO₃) as the absorbent keeps the circulating solution primarily as an aqueous sodium-based solution. This chemistry is less corrosive and less prone to scaling than calcium-based slurries. Pumps, piping, and equipment experience less erosion, corrosion, and plugging. Equipment operation and maintenance are therefore easier compared to lime-based systems.
High SO₂ Removal Efficiency
Sodium-based absorbents react quickly with SO₂. This fast reaction rate allows operation at a lower liquid-to-gas ratio while still achieving high desulfurization efficiency. Typical SO₂ removal efficiency is 90 percent or greater.
External Regeneration and Precipitation
Absorbent regeneration and solids precipitation occur outside the absorber tower. The scrubber itself handles only clean sodium-based solution. This arrangement prevents scaling and wear inside the tower. Operational reliability is improved. Operating costs are reduced.
Reliable Tower Design
The absorber is an empty spray tower with no internal packing. This design provides high operating reliability and low risk of internal plugging or damage. Tower pressure drop is low, typically 600 Pascals or less.
Application Range
Dual alkali desulfurization is primarily used to remove SO₂ from flue gas. Typical applications include coal-fired boiler flue gas, coke oven gas, and industrial boiler exhaust gases.
Haihui Expertise
Dual alkali flue gas desulfurization is a proprietary technology developed and successfully applied by Haihui. The sodium-calcium circulation achieves regeneration and reuse of the absorbent. Operating costs are reduced. Scaling and plugging problems are effectively overcome. System operational reliability is improved. Haihui determines specific parameters based on each customer’s actual operating conditions.
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