SU1725991A1 - Method of catalytically disintegrating nitrogen oxides - Google Patents

Abstract

The invention relates to the technology of purification of gas mixtures from nitric oxide (I) with the help of catalysts and can be used in chemical technology and power plants. The purpose of the invention is to reduce the energy intensity of the process. The decomposition of nitrogen oxide (I) on zeolite H-mordenite is carried out in the presence of monoxide or nitrogen dioxide with a molar ratio НО (М02) / №О equal to 0.1-10. The method allows to reduce the heating of the source gas by 100 degrees. 1 tab.

Description

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The invention relates to the technology of purification of gas mixtures from nitric oxide (I) with the help of catalysts and can be used in chemical technology and power plants.

The known method of catalytic decomposition of nitric oxide (I) at temperatures of 350-1000 ° C on a palladium catalyst.

The disadvantage of this method is the use of an expensive catalyst. The method of decomposing nitric oxide (I) on H-mordenite zeolite at 400-700 ° C is the closest to the proposed one.

The disadvantage of this method is high temperature and, as a result, high energy costs for heating the gas.

The aim of the invention is to reduce the energy intensity of the process.

This goal is achieved by the fact that the catalytic decomposition of nitric oxide (I) on the H-mordenite zeolite is carried out in the presence of monoxide or nitrogen dioxide. In this case, the molar ratio MO (М02) / №0 in the initial gas is 0.1–10.

Decomposition of N0 in the presence of monoxide or nitrogen dioxide in comparison with the prototype makes it possible to reduce the process temperature by 100 degrees and reduce the energy costs of heating the gas mixture.

The table shows the results of experiments on the decomposition of N20 on H-mordenite zeolite at various NO (NO) / N20 ratios in the source gas.

The value of TAU given in the table corresponds to the contact time of the gas to be purified with the catalyst and is calculated by the formula

VKaT

TAU

.W

(with).

Xj

hO (L

yoo o

where War is the bulk volume of the catalyst;

W is the volume flow rate of the gas mixture to be purified.

The degree of conversion of nitric oxide (I) X (No. 0) is calculated from the dependence

X (N20)

N0 (N20) -NK (N20) No (N2 O)

where N0 (N20j and N «(# 0) are the initial and final number of moles N20 in the gas being cleaned, respectively.

As can be seen from the table, to achieve the same degree of decomposition of nitric oxide (I) at a constant contact time and at different MO (M02) / No. 0 ratios, different temperatures are required. In the range of the NO (NO) / N20 ratio of 0.1-10, the average temperature reduction is 100 ° C. Consequently, the energy costs of heating the gas to the operating temperature of the catalyst are reduced.

PRI me R 1. The gas mixture in the amount of 100 l / min, containing 1% by volume of nitrogen oxide (I) and 99% by volume of nitrogen, is mixed with 100 l / min of gas containing 0.1% by volume of monoxide nitrogen (the rest is air), heated to 480 ° C and passed through a reactor filled with 200 ml of H-mordenite. At the outlet of the reactor, the concentration of nitrogen oxide (I) is 0.03% by volume, nitrogen monoxide - 0.05% by volume. The conversion ratio # 0 is 0.94. The initial molar ratio of NO / N20 is 0.1.

Example 2. The gas mixture in the amount of 100 l / min, containing 1% by volume of nitrogen oxide (I) and 99% by volume of nitrogen, is mixed with 100 l / min of gas containing 1% by volume of nitrogen monoxide (the rest is air), heated to 490 ° C and passed through a reactor filled with 200 ml of H-mordenite. At the outlet of the reactor, the concentration of nitric oxide (I) is 0.02 vol. %, nitrogen monoxide - 0.5 vol. % The conversion of N20 is 0.95. The initial molar ratio of NO / N20 is 1.

PRI me R 3. A gas mixture in an amount of 100 l / min, containing 1 vol.% Of nitrogen oxide (I) and 99 vol.% Of nitrogen, is mixed with 100 l / min of gas containing 10 vol.% Monoxide. nitrogen (the rest is air), heated to 505 ° C and passed through a reactor filled with 200 ml of H-rdhenite. At the outlet of the reactor, the concentration of nitric oxide (I) is 0.03 vol. %, nitrogen monoxide - 5 vol. %

The conversion ratio # 0 is 0.95. The initial molar ratio of NO / N20 is 10.

PRI me R 4. A gas mixture in an amount of 100 l / min, containing 1% by volume of nitrogen oxide (I) and 99% by volume of nitrogen, is mixed with 100 l / min of gas containing O, 1% by volume of dioxide nitrogen (the rest is air), heated to 480 ° C and passed through a reactor filled with 200 ml of H-mordenite. At the outlet of the reactor, the concentration of nitric oxide (I) is 0.03% by volume, nitrogen dioxide - 0.05% by volume. The degree of conversion of N20 is 0.94. The initial molar ratio of N02 / N20 is 0.1.

PRI me R 5. A gas mixture in an amount of 100 l / min, containing 1% by volume of nitrogen oxide (I) and 99% by volume of nitrogen, is mixed with 100 l / min of gas containing 1% by volume of nitrogen dioxide ( the rest is air), heated to 490 ° C and passed through a reactor filled with 200 ml of H-mordenite. At the outlet of the reactor, the concentration of nitrogen oxide (I) is 0.02% by volume, nitrogen dioxide - 0.5% by volume. The degree of conversion of N, 0 is 0.95. The initial molar ratio Н0а / №0 is 1.

PRI me R 6. A gas mixture in an amount of 100 l / min, containing 1% by volume of nitrogen oxide (I) and 99% by volume of nitrogen, is mixed with 100 l / min of gas containing 10% by volume of nitrogen dioxide ( the rest is air), heated to 505 ° C and passed through a reactor filled with 200 ml of H-mordenite. At the outlet of the reactor, the concentration of nitric oxide (I) is 0.02% by volume, nitrogen dioxide - 5% by volume. The degree of conversion of N20 is 0.95. The initial molar ratio of N02 / N20 is 10.

Thus, when using the proposed method, the energy costs of heating the gas mixture to be purified are reduced.

Claims (1)

Invention Formula A method for the catalytic decomposition of nitric oxide (I), including heating of the initial gas mixture containing nitric oxide (I), and then passing it through a layer of H-mordenite zeolite, characterized in that, in order to reduce the process energy intensity, additionally t monoxide or nitrogen dioxide at a molar ratio of monoxide or nitrogen dioxide to nitrogen oxide (1) 0.1-10.