SU1593691A1 - Method of cleaning gaseous mixture from nitrogen oxides - Google Patents

Abstract

The invention relates to the chemical industry and can be used in the purification of gases from nitrogen oxides by absorption, in particular using a suspension of vanadium pentoxide in nitric acid. In order to reduce the specific consumption of the V 2 O 5 suspension, nitrogen oxides are in contact with the suspension in the presence of mordenite, wide-porous, with a pore size of 6.2-10 A or H-clinoptilolite with their mass ratio equal to (0.1-0.5): 1 . The gas mixture is cleaned in an absorber at a temperature of 20–25 ° C, and the spent V 2 O 5 suspension is regenerated in a stripper at 60–100 ° C. Compared with the prototype, this invention allows to reduce the specific consumption of the V 2 O 5 suspension by 1.67-1.75 times and to increase the volume of purified gas, as well as to reduce the energy consumption for the regeneration of the suspension. 1 tab.

Description

The invention relates to the chemical industry and can be used in the purification of gases from nitrogen oxides by absorption, in particular, using an acidic suspension of vanadium pentoxide.

The purpose of the invention is to reduce the specific consumption of a suspension of vanadium pentoxide in vanadium in nitric acid.

For this purpose, the contacting of nitrogen oxides with a suspension of vanadium pentoxide is carried out in the presence of mordenite granulated granules with a pore size of 6.2-10 A or H-clinoptilolite with a mass ratio to the suspension equal to (0.1-0.5): 1.

The gas mixture is cleaned at 20–25 ° C by passing it through an absorber into which granules with a size of 3-5 mm of mordenite of wide porous or H-clinoptilolite and a suspension of vanadium pentoxide are preloaded at a mass ratio of, respectively.

equal to (0.1-0.5): 1. The spent suspension is regenerated in a desorber at 60-100 ° C and returned to the absorber. Granules of mordenite wide porous and H-clinoptilolite do not regenerate.

These acid-resistant silica-containing substances in this process catalyze the oxidation of N0 to N02. This is confirmed by an increase in the volume of gas to be purified, since the absorption of N02 is 3 times less than V205. than on N0 absorption:

pH1.5

V205 + H20 - 2HV03. N0 + 3HV03 + 5HN03 3 (VOXN03) 2 + 4H20,

N02 HVOa + HN03 VO (N03) 2 + H2O.

Example 1. A mixture of air with nitrogen oxides was passed at a speed of 0.3 m / s through a sparger, placed in a cylindrical column with a diameter of 100 mm. 200 ml of pentoxide suspension were loaded into the column.

cl

with

sl o so o

vanadium in an aqueous solution of nitric acid containing, in wt.%: VaOs 5, HNOs 30, the rest is water, and 60 g of mordenite broadly porous. The mass ratio of the granules: suspension was equal to 0.3; 1. Gas purification was carried out at 20-25 0. The volume of purified gas was measured with a gas meter from the beginning of the experiment to the time it appeared on the exhaust 0.005 vol. % nitrogen oxides. Then the spent suspension was poured into a glass, covered with a lid and heated on a hot plate. Nitrogen oxides began to precipitate through a nozzle in a lid at 60 ° C. The excretion of nitrogen oxides was completed at 95-10 ° C. After completion of the regeneration, the suspension was cooled to 20-25 ° C and returned to the column. Analysis of the gas for NOx content was performed in the initial gas mixture periodically using a titration method, and at the exit from the column continuously by a coulometric sensor.

The volume of purified gas and the specific consumption of the suspension for its purification are shown in the table,

When processing the experimental results, the first 2-3 experiments were not taken into account in order to analyze the conditions corresponding only to the equilibrium state of the granules of an acid-resistant silica-containing substance. Each experimental point given in the table is obtained by averaging the results of 3-5 ogates. The mismatch of material balance, i.e. difference

between the amount of nitrogen oxides fed into the column with the source gas mixture and the amount of oxides bound in the form of EO (MOz) 2. did not exceed 15%.

Thus, the proposed method according to

in comparison with the known, it allows to reduce the specific consumption of a suspension of vanadium pentoxide in nitric acid by 1.67-1.75 times or to increase the volume of purified gas at a constant consumption of suspension. Besides,

in connection with a decrease in the consumption of the suspension, the energy consumption for its regeneration is reduced.

The formula of the invention. A method of purifying a gas mixture from nitrogen oxides, including contacting it with a suspension of vanadium pentoxide in nitric acid, characterized in that, in order to reduce the specific consumption of the suspension, contacting is carried out in the presence of wide-range mordenite granules with a pore size of 6.2-10 or H-clinoptilolite with their mass ratio to a suspension of vanadium pentoxide, equal to (0.1-0.5): 1.

NOx content in gas at inlet, vol. %

0.18

0.18 0.18

0.18

Claims (1)

Claim A method for purifying a gas mixture of nitrogen oxides of nitrogen, including contacting them, with a suspension of vanadium pentoxide in nitric acid, characterized in that that, in order to reduce the specific consumption of the suspension, contacting is carried out in the presence of granules of mordenite broadly porous with a pore size of 6.2-10 A or N-clinoptilolite with their mass ratio to a suspension of vanadium pentoxide equal to (0.1-0.5) :1. pw .......................... Example The content of вχ in the gas at the input de, about % Silica-containing substance Pore sizes, A The mass ratio of granules: suspension The volume of purified gas, 1 · 10 ~ ² m ³ The specific consumption of the suspension, l / m ³ 1 0.18 Mordenite , 6.2 10 0.3: 1. 101 0.198 2 0.18 broad-pore N-clinoptis 8.0 0.3: 1 103 0.194 3 0.18 LOLIT Same 8.0. 0.1: 1 99.5 0.201 4 0.18 8.0 0.5: 1 104.5 0.191 5 (famous) 0.18 - - - 65 0.335 Compiled by L. Popova Editor L. Zaitseva Tehred M. Morgenthal Corrector N.Korol Order 2788 Circulation 577 Subscription VNIIIPI of the State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035. Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Plant Patent, Uzhgorod, Gagarin St. 101