The method of flue gas purification in waste incinerators can be roughly divided into several types:
1.1 spray drying method
A high-speed rotating spray head is arranged in the upper part of the absorption tower, and when the slurry for purifying the acid gas is sprayed onto the spray head, it is atomized and neutralized with the flue gas entering the tower, thereby removing harmful substances in the flue gas. Acid gas. The particulate matter in the flue gas is captured by the bag filter in the back, thereby achieving the purpose of dust removal and acid removal.
1.2 Suspended fluidized bed method
The utility model is characterized in that: the boiler fly ash and the added deacidification agent (reactive or incompletely reacted) are used as circulating materials, and the surface area is large, and the reaction activity and reaction surface area between the gas, the solid and the liquid are extremely large. , mixing, good contact, heat transfer, mass transfer is very strong. The repeated circulation of dust increases the residence time of the deacidification agent in the absorption tower, thereby improving the utilization rate of the deacidification agent.
If a high deacidification effect is to be achieved, the amount of circulating ash is very large, and the dust concentration entering the bag filter is extremely high, which can reach 1000 g/m3. The requirements for the bag type dust collector are high, and it is generally preferred to provide a pre-duster in front to reduce the dust load of the bag filter. Therefore, the requirements for the filter bag are also high and the resistance is low.
1.3 NID method
Also known as humidification ash cycle desulfurization technology. It usually uses CaO as a desulfurizer, and it is digested into Ca(OH)2 by adding water in a special digester. Then, the recycled ash collected by the dust collector is added to the mixing humidifier, and the water is humidified and sent to the desulfurization tower. After reacting with the hot flue gas in the tower, enter the dust collector together.
1.4 Dry and wet purification method——pipeline jet flue gas desulfurization technology
This method is currently a method for treating waste incineration flue gas to meet environmental protection requirements, and is most economical and convenient for maintenance and management. Compared with the semi-dry rotary spray drying, it does not require a pulping system, the nozzle is not easy to wear, and the maintenance is simple; compared with the fluidized bed deacidification tower, there is not a large amount of circulating ash returning to the deacidification tower, and no deacidification tower is produced. The danger of bed-slipping also reduces the load on the baghouse, reducing system resistance and saving operating energy.