Method and device for oxidizing sulphite grout in wet flue gas desulfurization process

Abstract

The invention discloses a method and a device for oxidizing sulphite grout in a wet flue gas desulfurization process. The method comprises the following steps: (1) collecting the sulphite grout generated due to the absorption of alkali liquid at an upper section of a desulfurization tower into a grout tank at a lower section of the same desulfurization tower; (2) introducing oxygen-containing gas into a creeping discharge reactor outside the desulfurization tower, and converting the oxygen-containing gas into active gas containing oxygen active substances; (3) injecting the active gas as an oxidizing agent into the sulphite grout, and oxidizing the sulphite grout to form sulfate grout. According to the device, the creeping discharge reactor is arranged outside the grout tank, so that the oxidation rate is increased, the use amount of the oxygen-containing gas is reduced, meanwhile, phenomena of electrode corrosion and grout backflow are avoided, a wet desulfurization absorption process and an oxidation process are integrated and are finished in the same desulfurization tower, an additional oxidation reactor is omitted, the process is simplified, and the cost is lowered.

Description

technical field [0001] The invention relates to flue gas desulfurization technology, in particular to a method and equipment for sulfite slurry oxidation in wet flue gas desulfurization technology. Background technique [0002] Wet coal-fired flue gas desulfurization methods mainly include limestone / lime-gypsum method, ammonia method, magnesium method and sodium method. 2 reaction to generate sulfite, and then oxidize sulfite into sulfate for recycling, namely: including absorption process, oxidation process and by-product disposal process, among which, the oxidation process of sulfite slurry is related to the quality of desulfurization by-products, slurry Pool volume and oxidizing air injection volume. In the wet flue gas desulfurization process, the sulfite oxidation method is mainly the forced oxidation method. The traditional process is to use a blower or an air compressor to blow air into the sulfite slurry, and use the oxygen in the air to oxidize the sulfite. Due to...

AI Technical Summary

Problems solved by technology

In the wet flue gas desulfurization process, the sulfite oxidation method is mainly the forced oxidation method. The traditional process is to use a blower or an air compressor to blow air into the sulfite slurry, and use the oxygen in the air to oxidize the sulfite. Due to the low oxygen oxidation ability, it is necessary to blow in several times the theoretical equivalent of oxygen to oxidize sulfite, which leads to an increase in the amount of air blown in, and then needs to be equipped with a high-power fan, which eventually leads to an increase in the operating cost of sulfite oxidation; moreover , because the rate of oxygen oxidizing sulfite is low, it is necessary to increase the sulfite oxidation time, so the volume of the oxidation zone (slurry pool) in the desulfurization tower also increases, resulting in an increase in the volume of the desulfurization tower and an increase in equipment costs

[0003] In order to improve the oxidation efficiency of sulfite slurry, researchers have carried out a series of studies in recent years. The Chinese invention patent with the publication number CN102188882A discloses an integrated method and special equipment for flue gas desulfurization, denitrification and heavy metal removal. The publication number is CN102188883A The Chinese invention patent discloses a new type of desulfurization and denitrification heavy metal integrated flue gas purification process and device. A device and method for simultaneous desulfurization and denitrification of flue gas by oxidation combined with double-tower washing. The Chinese invention patent with the publication number CN101602537B discloses a treatment method for ozone-enhanced oxidation of sulfite aqueous solution. The Chinese invention patent with the publication number CN102358621A discloses an ozone The method of oxidizing ammonium sulfite or ammonium nitrite, the basic process of these methods is to use the ozone generator to prepare ozone, and then inject the ozone directly into the sulfite slurry tank of the desulfurization tower, or mix it with oxidizing air and then inject it into the desulfurization Tower sulfite slurry tank, oxidized sulfite, the problems of these methods are that the ozone generator produces high concentration ozone and is transported to the slurry tank of the absorption tower through pipelines, and the ozone is decomposed during the transportation process, resulting in ozone loss; the second problem is that ozone The limited amount of gas processed by the generator leads to a limited amount of ozone generated, which makes it difficult to meet the oxidation requirements of desulfurization slurry with large flue gas volume; the third problem is that the ozone generator needs to be equipped with air separation equipment and high-power high-frequency power supply, resulting in equipment costs and operating costs Increase

However, the practical application shows that this method has the following disadvantages: 1) The gas-phase surface discharge system is directly placed in the slurry tank, which makes the electrode system easily corroded; 2) When the slurry pressure is greater than the gas pressure inside the electrode system, the slurry is easy to pour back Enter the discharge electrode system, resulting in damage to the discharge electrode system; 3) The oxidation rate and oxidation rate of sulfite slurry still need to be improved

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