SU1197705A1 - Method of cleaning gases from nitrogen oxides - Google Patents

Abstract

A METHOD FOR CLEANING GAS FROM NITROGEN OXIDES, including contacting gases with an absorber — an aqueous solution containing a metal oxide of variable valence; high degree of purification; an alkali solution is used as an aqueous paci- thi; bismus oxide Ta is used as a metal oxide (iv, while contacting gases is carried out in the anode space of electrolysis and simultaneously with regeneration at a contact time of not less than 0.50, 6, and alkaline scavenger maintained by electrodialysis.

Description

The invention relates to methods for purification of gases from nitrogen oxides and may find application in the chemical and metallurgical industries.

The purpose of the invention is to improve working conditions and simplify the process while maintaining a high degree of purification.

Example. The initial solution. Containing a suspension of '} Bi (N0 ^) ^ in an amount of 30-40 g / l is fed into the anode space of the electrolyzer, where it is electrochemically oxidized to Βί ₂ 0 ₄ at a current density of 0.323-0.334 and a potential value of 1.3- 1.4 V · The p-fc network is used as the anode, and the cathode ^ W is used. A gas containing N0 _x '; (θ, 2 vol.%) With a linear velocity of 0.3 m / s is also supplied to the anode space of the electrolyzer. ^! Nitrogen oxides are oxidized by bismuth oxide IV resulting from electrochemical oxidation to HNO ₅ .

The oxidation process Ν0 _χ with Βΐ ₂ 0.4 in a slightly alkaline medium should be carried out at pH = 8–9 .. Since the regeneration process gradually produces an acid that interferes with the anodic oxidation of B; 0Ν0 ^ * use electrodialysis, which allows the thief to regulate the acidity of using a membrane.

When using electrodialysis, a solution containing B (OMO _{? Is} circulated, passing sequentially through the electrolyzer and electrodialyzer.

In the electrolyzer, as in electrodialysis, an AM-1 industrial homogeneous membrane was used.

The degree of absorption of nitrogen oxides at a contact time of 0.5 s corresponds to 99.9%. ¹

The conditions for the oxidation of nitric oxides with Βί (ΐν) oxide in a slightly alkaline medium 15 were selected on the basis of a series of experiments and are presented in Table I.

The study of the electrochemical oxidation of the absorber was carried out ₂₀ by the method of taking polarization curves. The results are shown in table.2_. '>

The anode process can be represented by the following electrode reaction:

²⁵ 2BiO ⁺ + 2H ₂ O = Bi £ O ₄ + 4Η * + 2ε ~, at the cathode:

2Н ₂ О + 2е '= Н ₂ + 20Н ~

The total reaction is 2BiO ⁺ + 2H ₂ 0 = BijO * + 4H ⁺ .

Table 1

------ t to Content Time Power Bi (N0 _$ ) ₃ contact cleaning in suspension, g / l from %

323 30-40 0.2 75,2 0.3 82.5 0.4 97.7 0.5 99.9 0.6 99.9 Table and 2 t, K Content Potential Density Exit Bi (N0 3) 5 in suspension, g / l E, B current, 1, and / m ^g current% 1,2 0.14 97.2 323 30-40 1.3 0.323 97.5 14 0.334 97.7 1,5 0.42 87.5

VNIKLI Order 7650/7 Circulation 658 ____ Subscription

Affiliate PPP ^ Patent ^ ’^ g. Uzhhorod, st. Project, 4

Claims (1)

METHOD FOR CLEANING GASES FROM NITROGEN OXIDES, including contacting gases with an absorber - an aqueous solution containing variable-valence metal oxide, and electrochemical regeneration of an absorber in an electrolyzer with a semipermeable membrane, characterized in that, in order to improve working conditions and simplify the process when maintaining a high degree of purification, an alkaline solution is used as an aqueous solution, and bismuth oxide (1 ¥) is used as a metal oxide _? wherein the contacting of gases is carried out in the anode space of the electrolyzer simultaneously with regeneration at a contact time of at least 0.50.6 s, and the alkaline medium of the absorber is maintained by electrodialysis. ►o »>