SU1119719A1 - Method of cleaning gases from nitrogen oxides - Google Patents

Abstract

A METHOD FOR CLEANING GAS FROM NITROGEN OXIDES, including contacting gases at elevated temperatures with a catalyst — transition metal oxides deposited on aluminosilicate, characterized in that, in order to increase the degree of purification, the purified gases are passed through a layer of activated carbon with a temperature of 500-600 ° C ;WITH.

Description

WITH

with

The invention relates to methods for purifying gases from nitrogen oxides and may find application in the chemical and petrochemical industries.

A known method of purifying gases from nitrogen oxides is based on passing exhaust gases through heated coke, in which the exhaust gases are mixed with carbon dioxide at a ratio (NO, NOa): CO2 1: 1-1: 2, and coke is heated to 430550 ° From 1.

However, this purification method does not ensure complete reduction of nitrogen oxides.

The closest to the invention in its technical essence and the achieved result is a method of purifying gases from nitrogen oxides at 260-530 ° C on a catalyst, which is Cr, Mn, Fe, Co, Ni, Cu oxides deposited on aluminosilicate. The method provides a degree of purification up to 90% 12.

The purpose of the invention is to increase the degree of purification.

This goal is achieved by the fact that according to the method of purification of gases from nitrogen oxides, which includes contacting gases at elevated temperatures with a catalyst — oxides of transition metals deposited on aluminosilicate, the gases to be purified are passed through an activated carbon layer with a temperature of 500,600 ° C.

The technology of the method is as follows.

Drainage gases containing nitrogen oxides are fed to activated carbon preheated in the first tank with a temperature of 500-600 ° C. The resulting gas mixture containing NX, CO., CO and NO with a ratio of NO .CO of 1 is fed into a container with a layer of aluminosilicate promoted with metal oxides with a temperature of 250-300 ° C. At the same time, air is supplied through the pipeline to the second tank. The heated elements include before the supply of the purified gases in the tank with coal and

catalyst. Purified gases are vented through the valve to the atmosphere. Flowmeters regulate optimal flow, ensuring complete reduction of nitrogen oxides. At the end of the Process, a compressed gas is fed into the grate of the first tank and the resulting zone is removed from the grate during the combustion of the activated carbon through filter valves.

With the help of the gas pumping device in the process (coal combustion, the tank is filled and the carbon level is permanently positioned relative to the heating element. Temperature sensors regulate the operation of the heating elements.

Example 1. Drainage gas with an initial NOx concentration of 1.5 g / l is passed through a layer of activated carbon at 480 ° C, after which apyumosilicate at 300 ° C is fed to the catalyst bed CuO, CrO3, to obtain 87.8% NOx purification - CO is not detected in the purified gas.

Example 2. Under the conditions of Example 1, but at a temperature of activated carbon of 500 ° C, a 92.1% degree of purification of NOx is obtained. CO is not detected in the purified gas. Example 3. Under the conditions of Example 1, but with an activated carbon temperature of 550 ° C, a 97.6% degree of removal of NOx is obtained. CO is not detected in the purified gas.

Example 4. Under the conditions of example 1, but at a temperature of activated carbon of 600 ° C, 0, 99.8% of the degree of purification from is obtained in an amount of 2.5% by volume.

Example 5. Under the conditions of Example 1, but with

activated carbon temperature of 620 ° C

a degree of purification is obtained of 96.3% OTNOx.

CO in the purified gas was 14.8%, which

requires special cleaning.

As follows from the examples, the proposed method allows to increase the degree of purification from NOx to 92.1-99.8% versus 90% in the known method, while at a temperature of 0 activated carbon less than 500 ° C, an increase in the degree of purification is not achieved, and at a temperature of above 600 ° C in the gas after purification, a large amount of harmful CO impurity appears.

Claims (1)

METHOD FOR CLEANING GASES FROM NITROGEN OXIDES, including contacting at elevated temperature gases with a catalyst - transition metal oxides deposited on aluminosilicate, characterized in that, in order to increase the degree of purification, the gases to be purified are preliminarily passed through an activated carbon layer with a temperature of 500-600 ° FROM.