Desulfurized slurry blinding prevention and treatment methods employing wet process

Abstract

The invention discloses desulfurized slurry blinding prevention and treatment methods employing a wet process, and belongs to the technical field of a wet flue-gas desulfurization system of a thermal power plant. The blinding prevention method is characterized by comprising the steps of carrying out classification control and periodic analysis aiming at different running conditions in limestone slurry supply adjustment to grasp the chemical ingredient of the slurry and correct deviation timely; and timely adopting an adjusting technology to prevent blinding aiming at the poisoning blindness precursor; and the blinding treatment method comprises the steps of reasonably reducing the slurry supply amount to digest excessive limestone and control the pH value of the slurry to reduce to the lowest threshold; reasonably increasing the slurry supply amount to ascend and restore the pH value of the slurry; and reasonably controlling the slurry supply amount to restore the desulphurization efficiency to a design value. By application of the methods, the probability of poisoning blindness accidents can be effectively reduced; the reliability and the stability of the desulphurization system are improved; meanwhile, the treatment can be timely and effectively carried out aiming at the poisoning blindness accidents, so that the system can rapidly get rid of adverse effects caused by the poisoning blindness accidents; and the extent of injury caused by the poisoning blindness accidents can be reduced.

Description

technical field [0001] The technical field of the wet desulfurization system of the present invention, in particular, relates to a method for preventing and treating blindness caused by wet desulfurization slurry applicable to a wet desulfurization system of a thermal power plant. Background technique [0002] In the field of air pollution control in thermal power plants in my country, wet desulfurization technology accounts for more than 90% of the entire post-combustion flue gas treatment technology. The feature of this process is that the entire desulfurization system is located after the dust collector of the coal-fired boiler, and the desulfurization project is carried out in the solution. It has the characteristics of fast reaction speed and high desulfurization efficiency. Among the flue gas desulfurization treatment technologies of thermal power units in service, the limestone-gypsum wet desulfurization technology is the mainstream. The early limestone-gypsum wet desu...

AI Technical Summary

Problems solved by technology

[0005] 2) The density of the slurry in the absorption tower is high and the CaSO in the slurry is not discharged in time. 4 *2H 2 O saturation inhibits CaCO 3 dissolution reaction;

[0006] 3) After electrostatic precipitating, the dust content is high or the heavy metal content is high, forming a stable compound in the slurry of the absorption tower, which is attached to the surface of the limestone particles, affecting the dissolution reaction of the limestone particles, resulting in the ineffective adjustment of the pH value of the limestone slurry;

[0008] 5) The quality of process water is poor: the concentration of chloride ions in the system is high, and the quality of limestone powder is poor, which causes limestone blind spots in the slurry of the absorption tower;

[0009] 6) Exceeding the standard of fluoride ions: trivalent aluminum in the slurry reacts with fluoride ions to form AlF 3 The complexes with other substances are attached to the surface of limestone in a viscous flocculation state, which will lead to: closing the surface of limestone particles to prevent its dissolution, reducing the pH value of the slurry, which will inevitably lead to a decrease in desulfurization rate; this requires adding limestone to Adjust the pH value of the slurry. At this time, if the limestone slurry supply flow is automatically input to ensure the desulfurization efficiency, the limestone slurry supply volume will be automatically increased to increase the pH value of the absorption tower, so that the limestone in the absorption slurry is excessive, and the entire system increases the limestone concentration. Consumes, reduces gypsum quality and destroys dewatering properties

[0010] 7) The oil content in the slurry is high, and too much oil will cause foam when it enters the absorption tower, and at the same time, it will affect the chemical reaction of desulfurization. After the oil has accumulated to a certain amount, carbon black, hydrocarbons and other substances in the oil will be wrapped in various Particle surface affects its mass transfer process, and affects gypsum crystallization and desulfurization efficiency; when the oil content in gypsum slurry reaches 250mg / m 3 , the dissolution rate of limestone is almost zero, and the SO 2 The absorption chemical reaction is basically terminated