The flue gas enters the desulfurization tower from the bottom of the tower through the flue. In the desulfurization tower, several layers (depending on the specific situation) of swirl plates are arranged. The swirl plate tower has good gas-liquid contact conditions. The lye sprayed from the top of the tower is atomized on the swirl plate to make the flue gas The SO2 in the liquid is fully absorbed and reacted with the sprayed lye. The clean flue gas after desulfurization and washing is dehydrated by the demister and then enters the heat exchanger, and the heated flue gas is discharged into the atmosphere through the chimney through the induced draft fan.
The double-alkali method uses a sodium-based desulfurizer for desulfurization in the tower. Due to the strong alkalinity of the sodium-based desulfurizer, the solubility of the reaction product after absorbing sulfur dioxide is large, and it will not cause supersaturated crystallization and cause scaling and blocking problems. On the other hand, the desulfurization product is discharged into the regeneration tank for reduction and regeneration with calcium hydroxide, and the regenerated sodium-based desulfurizer is sent back to the desulfurization tower for recycling. The dual-alkali desulfurization process reduces investment and operating costs, and is more suitable for desulfurization transformation of small and medium-sized boilers.
The dual-alkali flue gas desulfurization technology uses sodium hydroxide solution as the starting desulfurization agent, and the prepared sodium hydroxide solution is directly injected into the desulfurization tower to wash and remove SO2 in the flue gas to achieve the purpose of flue gas desulfurization, and then the desulfurization product is desulfurized. The agent regeneration tank is reduced to sodium hydroxide and then returned to the desulfurization tower for recycling. The desulfurization process mainly includes five parts: (1) absorbent preparation and supplementation; (2) absorbent slurry spraying; (3) contact and mixing of mist droplets in the tower and flue gas; (4) regeneration tank slurry reduction of sodium base; (5) Gypsum dehydration treatment.