Background technology:

The limestone/lime gypsum flue gas desulfurization technology began to emerge in the 1960s and 1970s and has become a mature process for flue gas desulfurization. Due to the fact that the oxidation of potassium sulfite requires a lower pH value, early limestone gypsum methods used the method of external oxidation and acid adjustment to adjust the pH value of lime slurry to prepare desulfurization gypsum. Subsequently, a desulfurization process with lower pH value absorption and oxidation inside the tower was gradually developed, which improved the performance of the desulfurization system and produced desulfurization gypsum as a byproduct. Chinese invention application 9 discloses a dual loop limestone/lime gypsum wet flue gas desulfurization method, which adopts a dual loop desulfurization tower spray system. Each loop system has a relatively independent spray layer, slurry circulation pump, and slurry collection device, and there is a connecting pipeline between the two slurry collection devices. The dual loop desulfurization tower spray system operates at different pH values, with the upper loop slurry pH controlled between 5.5-6.8 and the lower loop slurry pH controlled between 4-5.

technological process:

The flue gas enters between the lower loop slurry circulation box and the lower loop spray layer in the desulfurization tower. It first reacts with the slurry sprayed from the lower loop spray layer, while cooling down. Then, it further reacts with the slurry sprayed from the upper and upper loop spray layers. The purified flue gas after desulfurization is discharged after passing through the demister. The limestone slurry is transported to the upper loop slurry circulation box, and the reacted slurry is collected in the upper loop slurry collection tray located in the middle of the desulfurization tower, and returned to the upper loop slurry circulation box through pipelines. Part of the slurry in the upper loop slurry circulation box is sent to the lower loop slurry circulation box at the bottom of the desulfurization tower through a connecting pipeline, and the slurry that reacts with the flue gas after spraying returns to the lower loop slurry circulation box. Air is blown into the bottom of the desulfurization tower to oxidize the sulfite slurry in the lower loop slurry circulation box into potassium humate slurry, which is then pumped out by the gypsum discharge pump and sent to the gypsum dehydration system.

The device and method for flue gas desulfurization and dust removal using carbide slag gypsum method include:

The desulfurization tower, wet electrostatic precipitator defogger, sedimentation tank, dehydration system, and slurry preparation system adopt a two-stage desulfurization tower and wet electrostatic precipitator defogger series structure. Compared with the traditional dual tower dual cycle desulfurization process, the desulfurization efficiency can reach over 99%, while reducing the occupied space of the desulfurization tower. The present invention uses carbide slag as the desulfurizer to treat waste, with significant environmental and economic benefits. At the same time, two-stage cyclone classification pulping is used to produce different specifications of slurry. While the absorption efficiency of the desulfurization tower is improved, the internal packing layer of the desulfurization tower is avoided from being blocked. Combined with the wet electrostatic precipitator defogger, the efficiency is further improved, especially for PM2.5, which can almost achieve zero emission of dust such as PM2.5. It is also very effective in haze control.

The characteristics of the calcium carbide slag gypsum flue gas desulfurization and dust removal device include:

A desulfurization tower, comprising a spray tower and a packed tower connected in series through a flue, wherein the desulfurization tower is a spray tower, the secondary desulfurization tower is a packed tower, and the flue gas is fed into the desulfurization tower from the flue gas inlet; The wet electrostatic precipitator is connected to the flue gas outlet of the secondary desulfurization tower through a flue. The wet electric spray layer inside the precipitator is connected to the clear liquid tank through a wet electric circulation pump pipeline; The sedimentation tank is connected to the secondary desulfurization slurry tank at the bottom of the secondary desulfurization tower. The upper clear liquid of the sedimentation tank is connected to the clear liquid tank, and the bottom of the sedimentation tank and the clear liquid tank are respectively connected to the desulfurization slurry tank at the bottom of the desulfurization tower; The dehydration system is connected to the bottom of the desulfurization slurry pool through a pipeline. The desulfurization slurry pool is connected to an oxidation air duct, which oxidizes the slurry settled at the bottom of the pool into gypsum slurry and sends it into the dehydration system.