SU679229A1 - Method of cleaning gas from sulphur dioxide - Google Patents

Description

I

The invention relates to the field of gas purification from cepifflCToro anhydride and can be used in the chemical industry.

A known method of cleaning gases from sulfur dioxide by neutralizing the latter with lime milk 1J. However, the gypsum resulting from the treatment of gases causes the equipment to become blocked. Other known methods, ammonia, magnesite, and catalytic, either do not provide regeneration of the absorbers, or are very sensitive to impurities in gases and require significant capital investment 2.

The closest to the invention in its technical essence is a method for purifying gas from sulfur dioxide by absorbing the latter with an acidic suspension of vanadium pentoxide 3. At the same time, the oxidation of sulfur dioxide by the ion of pyvalent vanadium occurs in the liquid phase. The resulting vanadium sulfate solution is sent for regeneration, which consists in treating the absorption solution with ammonia. As a result of neutralization, ammonium sulfate and vanadium oxide hydrate are formed. After filtration, the vanadium hydroxide is calcined at 600 ° C to obtain vanadium pentoxide, which is recycled. The disadvantage of this method is the low absorption capacity of the suspension.

The aim of the invention is to increase the absorption capacity of the suspension. The goal is achieved by the proposed method of gas purification from sulfur dioxide by absorbing the last acidic suspension of vanadium pentoxide, followed by regeneration of the suspension electrochemically at 35-40 ° C, the decomposition potential is 1.017-1.193 V and current capacity is 225-350 A / m

Distinctive features of the method are the implementation of the regeneration of the suspension electrochemically at, the value of the decomposition potential 1,017-1,193 V and a current density of 225-350A / m

Claims (2)

The process technology is as follows: waste gases containing sulfur dioxide are treated with a sulfuric acid suspension of vanadium pentoxide in scrubbers. while at a discount (| gas station: the sulfur dioxide is oxidized by the petvioleptic vanadium ion, possessing the oxidative property: regenerated. At the same time, the tetravalent vanadium is oxidized to the equivalent state at the anode. At the anode, the oxidation is oxidized with atomic oxygen:% 1, 3 results in which the peroxide cation VO is formed, which has a greater oxidative capacity Compared with VOj ion obtained by diluting pentoxide with vanadl in 10% sulfuric acid. The concentration of vanadium peroxide pentoxide in the absorption solution after regeneration by electrochemical route is up to 60 g / l, which increases the chemical the capacity of the absorber and allows for a decrease in the reaction volume when absorbed is 1. The electrolysis process is uninterrupted at 110 ° C, the potential is also 1-1.193 V, and the current density is 225-350 A / m. The current output is 68.9-91.2%. Example. The initial solution is a suspension containing 1:10 by volume of insoluble vanadium pentoxide in a solution of pk 10% acid, in which, after regeneration, up to 60 g / l of the OOZ peroxide cation, which has oxidizing properties, are contained. This solution after regeneration is fed to the scrubber irrigation. Since the absorption capacity of the solution has increased, a contact time of 0.075 seconds is sufficient to obtain an absorption rate of 98.8%. Linear gas velocity 0.3 m / s. Waste industrial gases, gases with a content of 0.5-2 vol. % arrive at school. The gas temperature should not exceed 40-50 ° C. The waste solution with a salt concentration of up to 200 g / l is fed into the anode cells of the electrolytic bath. The electrolytic bath is a ceramic tank divided by a septum. Each half of the bath is divided by porous porcelain diaphragms into two anodic and three cathode separated. The thickness of the diaphragm is 3 mm. The anode is a platinized titanium rod, the cathode is a graphite rod. The electrolyte flows by gravity through all the cells. The outgoing anolyte is directed to the collector, compressed air is squeezed into the tank and fed to the cathode cells of the bath. 4 The mechanism of the process at the anode can be represented by the following reactions: -. I. Ij I-S P t W -I. 20N VOSO. 20 -V03- - €. The reaction proceeds at the cathode: The electrolysis process proceeds continuously at 40 ° C. Vanadium sulfate oxidation occurs in the anode compartment and some increase in the concentration of sulfuric acid occurs, while in the cathode separation, the concentration of sulfuric acid decreases. The conditions of electrochemical oxidation were chosen based on the study of polarization curves. The choice of optimal temperature ranges, decomposition potential and current density is justified by the following considerations. Apply A decrease in temperature above 40 ° C leads to an overrun of the current, and the use of a lower temperature slows down the chemical reaction of the formation of the peroxide cation POS. A study of the polarization curves leads to the conclusion that the decomposition potential cannot be less than 1.017 V (the process does not proceed). The use of a decomposition potential greater than 1.193 V does not have a physical meaning. It was experimentally found that the current density at a potential of 1.193 V can be increased from 225 to 350 A / m, since this does not require an increase in the area of the year and leads to its more economical use. The conditions for electrochemical oxidation are presented in the table; temperature 30 ° C, VOSO concentration 200 g / l, NZO concentration: 10%. The concentration of pyvalent vanadium in the whole VOs reaches 60 g / l. The use of the proposed method of purifying waste sulfur dioxide with sulfur dioxide provides, as compared with the prototype, an increase in the absorption capacity of the suspension by a factor of three. Claims A method for purifying a gas from sulfur dioxide by the absorption of an acidic suspension of vanadium pentoxide followed by regeneration of the suspension, characterized in that 5 6792296 in order to increase the absorption capacity1. Bulletin of NIITEKHIM, No. 11. p. 46, suspensions, regeneration carried out by elect-1961. rochemically at 35-40 ° C decomposition potential equal to 1,017-1.93 V, 2. USSR author's certificate number 231534, and current density of 225-350 cells. From 01 to 17/60, 1968. Sources of information taken3. Avtopsky certificate of the USSR No. 362630, into consideration with the expertise. B01 O 53/16, 1969 (prototype).