Dust Collector SO2 Purification Spray Tower Desulfurizer

Dust Collector SO2 Purification Spray Tower Desulfurizer

1. Brief introduction

The SO2 purification tower is widely used for gas purification in the brick and tile industry. It uses alkali as a solvent and can absorb acidic gases such as SO2, So3, HCl etc.

The flue gases from the furnace enter the desulfurization tower tangentially, the fine smoke and dust contained in the flue gases are absorbed and collide with each other to form particles. Under the action of centrifugal force, they are thrown onto the wall of the tower and, under the action of a film of water, are pulled to the bottom of the tower; The exhaust gas swirls up the tower wall and collides at high speed through the rotating layer with the atomized desulfurization liquid. At this time,  the three-phase flow of gas, liquid and solid comes into complete contact, and the SO2 in the exhaust gas is mostly absorbed by the alkaline components in the liquid, thereby completely purifying the exhaust gas.The cleaned flue gases are dewatered using demisters and discharged via a flexible chimney.

The residual liquid after desulfurization is drained from the bottom of the tower into the ash washing channel. After sedimentation in the clarifier (with a small amount of dust in the flue gas), the clarified liquid is then sent via a desulfurization pump to the tower body, where it is recycled. A small amount of wastewater is discharged from the desulfurization plant; After a certain period of time, the sludge present in the circulation tank is cleaned manually or mechanically.

2. Main technical parameters

3. The advantages of Alkali type desulfurizer tower

• The system has a small liquid-to-gas ratio and low operating energy consumption. The desulfurization absorption liquid is sodium-alkali solution and the desulfurization efficiency is high, generally above 90%.
• Using swirling jet and pressure atomization technology, the equipment resistance is small.
• Sodium-alkali desulfurization, the circulating water is basically an aqueous solution containing Na+. During the circulation process, there is no corrosion or blockage of water pumps, pipelines, and equipment. The system operation is stable and reliable, and it is convenient for equipment operation and maintenance.
• The regeneration of the absorbent and the precipitation of desulfurization slag occur outside the tower, avoiding blockage and wear in the tower, improving operational reliability and reducing operating costs;
• When the coal type and boiler load change, the system pH value, liquid-gas ratio and other factors can be appropriately adjusted to ensure the realization of desulfurization efficiency.
• The process is simple and not easy to scale. The system does not discharge desulfurization wastewater and does not produce secondary pollution. It is more suitable for use in industrial boilers and furnaces.

4. The working principle

The desulfurizer tower uses NaOH solvent to absorb the SO2 in the flue gas, the reaction equation as below:

2NaOH+SO2→Na2SO3+H2O (1)

Na2SO3+H2O+SO2→2NaHSO3 (2)

Notes:

a. Equation (1) represents the main reaction of SO2 absorption by the desulfurization solution during the start-up stage, when the NaOH solution absorbs SO2 and the pH value of the regeneration solution is high (above 8);

b. Equation (2) represents the main reaction when the pH value of the desulfurization solution is low (5-8).

c. As the absorption process going, the amount of Na2SO3 in the absorption solution increases, and the absorption capacity of the absorption solution decreases. It is necessary to add alkaline solution to the absorption solution, maintain a relatively stable concentration ratio of Na2SO3 in the absorption solution, and regularly discharge a portion of the waste liquid.

d. The acidic gases such as SO3 and HCl contained in the flue gas will also be absorbed by the absorbent.

5. The structure diagram of desulfurizer tower

The SO2 absorption system consists of a desulfurization tower, an internal spray system, a cyclone, a mist separator, an absorption liquid circulation pump, a pipeline power supply  and other components.

6. Detail images: