SU1572686A1 - Method of cleaning waste gases from vapours of organic solvents - Google Patents

Abstract

The invention relates to the technology of purification of waste gases from organic solvent vapors used in the electrical, chemical and engineering industries, which allows to accelerate the regeneration process and reduce energy consumption for cleaning. Exhaust gases containing vapors of toluene, ethyl alcohol and acetone are cooled in a layer of heat-accumulating ceramic heat-accumulating nozzle and passed through a layer of active carbon. After saturation, the layer is regenerated by passing a gas stream. After regeneration, a part of the gas stream is heated in a layer of heat-accumulating nozzle and fed to catalytic oxidation, and then to coal regeneration. The other part of the gas stream after regeneration is passed through an additional layer of active carbon and combined with the gas stream supplied to catalytic oxidation. After reaching the residual capacity of the main layer of coal equal to 0.2-0.4, the entire gas flow after regeneration of the main layer is passed through an additional layer of coal and fed to catalytic oxidation. The regeneration process is accelerated by 32–36%, the energy consumption for the purification of 1000 m ^{3 of} exhaust gases is reduced by 0.012– 0.016 Gcal. 1 il. 1 tab.

Description

The invention relates to the cleaning of gas-vapor mixtures from solvents and can be used in the electrical, chemical and engineering industries.

The aim of the invention is to accelerate the regeneration process and reduce energy consumption for cleaning.

The drawing shows schematically a device for carrying out the cleaning of flue gases from an example of this hydrocarbon.

The device contains an adsorber 1 by its fitting 2 for supplying waste gases and a fitting 3 for exhaust-purified flow, a catalytic reactor 4, a heater 5, a fan 6 for circulating a desorbing gas flow, a heat regenerator 7 and an additional adsorber 8 parallel to it. the heat regenerator 7 with the adsorber 8 connected in parallel, the fan 6, the heater 5 and the catalytic reactor 4 are interconnected in series with the gas ducts and form a closed loop of the desorbing gas flow. To supply the waste gases to the purification device, there is a pipe 9, to remove a purified gas stream, a 10 s a pipe to remove the products of complete catalytic oxidation desorbate hydrocarbons from the device - pipe 11. To adjust the operating modes of the device, gate valves 12-19 are installed.

Activated carbon (for example, brand АR-3) is located as adsorbent in adsorbers 1 and 8; for example, a nichrome wire catalyst with palladium coating (type KN) is placed in catalytic reactor 4. Energy heaters are installed as heating elements in heater 5 TENY). The heat regenerator 7 is filled with a ceramic heat-accumulating nozzle, for example, Raschig rings.

The method is carried out as follows.

Exhaust gases, for example, air containing vapors of toluene, ethyl alcohol, acetone with a total concentration of 4-6 g / m3, at 120 ° C through pipe 9 with the open position of the gates 12.20 and 21 are directed to the heat regenerator 7, passing what

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The gats that are cooled are cooled, for example, to 30-40 ° C, they are fed through the nozzle 2 to supply waste gases to adsorption 1, where the hydrocarbon impurities are adsorbed in the activated carbon layer, and the purified stream through the nozzle 3 when the gate 13 is open brought to the atmosphere.

After saturation of the adsorbent layer in the adsorber 1 (the appearance of hydrocarbon impurities behind the layer in the gas stream), the device for cleaning waste gases from hydrocarbon impurities is transferred to the adsorbent regeneration mode. For this, the gaibers 12 and 13 close, open the gates 14,16,17, 18, 19, turn on the fan 6 and the heater 5 and organize the movement of the gas volume in the circulation circuit in the direction indicated by the arrow. with a temperature of 30-40 ° C after the nipple 2 of the adsorber 1 is divided into two. One is sent to the heat regenerator 7, where the passage through the heat accumulator is heated to 90 ° C, and the second is passed through the adsorber 8, after which both streams are combined both by the fan 6 through the heater 5 and the catalytic reactor 4 at temperature, increasing from 60-70 ° C, through fitting 3 is fed to adsorber 1. Under the heat and displacement effects, adsorbed hydrocarbon impurities at a speed of 0.2-0.3 m / s desorb from the saturated layer of adsorbent to their concentration increasing in regenerating flow m 0 up to 20-30 g / m 39 is directed to the heat regenerator 7 and the adsorber 8, in which desorbed hydrocarbon impurities are re-adsorbed at a moving speed of 0.1-0.2 m / s, and the non-sorbed components are mixed with the heated heat-accumulating nozzle flow. The resulting gas-vapor mixture with a concentration of 4-6 g / m5 (providing catalytic oxidation without energy supply to heater 5) is fed to a catalytic reactor 4, where desorbed hydrocarbon impurities at 320 ™ 380 ° C and flow rate 16-20 thousand 0 1 / h oxide in the presence of a catalyst and in a circulating regenerating flow, the products of catalytic oxidation

sent to adsorber 1. The concentration of desorbed hydrocarbon impurities before the catalyst bed at 4-6 g / m3 when their content changes after adsorber 1 is ensured by changing the ratio of flow rates through the heat regenerator 7 and adsorber 8 desorbate by the positions of the gates 19 and 21.

Upon reaching the residual capacity of the regenerated adsorbent by adsorbed hydrocarbon impurities 0,, 2 (determined by the output concentration of hydrocarbons after adsorber 1, and then introduced into a temporary regeneration program), the entire circulating flow of regeneration products from adsorber 1 is sent to adsorber 8 desorbate For this purpose, the gate valves 20Li 21 are closed, and the gate 19 is set in the position providing the concentration after the generated adsorbent layer in the adsorber 8 at the level of 4-6 g / m3.

The amount of oxygen required for the complete catalytic oxidation of hydrocarbons, and the removal of excess oxidation products from the device is ensured by opening the gates 12 and 15, while air is supplied to the device through pipe Y, and products of complete catalytic oxidation of desorbed hydrocarbon impurities are removed through pipe 11. By reducing the hydrocarbon impurities after the adsorber 8 to 0 (or the effective level set by the program), the regeneration stage is stopped, the layers of the adsorbent are cooled by air and the device by opening the gates 10, 12, 19, .20 is switched to the flue gas cleaning mode.

The table shows the test results of the known and proposed methods. i

When the concentration of organic impurities in the exhaust gases is 4-6 g / m and the average calorific value of the desorption products is 4000 kcal / m3, the acceleration of the adsorbent regeneration process is 32-36%, and the energy consumption for purification of 1000 megs of exhaust gases is reduced by 0.012-0.016 Gcal .

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The method of purification of waste gases from organic solvent vapors, including their cooling in the layer of heat-accumulating nozzle, passing the active carbon through the layer, regenerating the coal by passing the gas stream obtained by catalytic oxidation of the gas stream after the heat-accumulating nozzle, so that that, with the chain of acceleration of the regeneration process and reduction of energy consumption for cleaning, a part of the gas stream after regeneration is passed through an additional layer of active carbon and combined with the gas stream, avaemym on catalytic oxidation of the residual capacity after reaching the base layer coal equal 0.2-0.4, lss gas stream after regeneration of the base layer is passed through a further layer of the coal and fed to a catalytic oxidation

thirty

The duration of the regeneration of the adsorbent to achieve the concentration of desorbate in the regenerating flow before the fan is 0.05 g / m3,

min78 52

Duration of the electric heating of the regenerating flow before the catalytic reactor up to 360 ° C, min 57 16 The share of the calorific value of the adsorbate, derived from the regeneration circuit of the adsorbent without using the heat balance of the regeneration stage0 42

Claims (1)

Claim The method of purification of exhaust gases from organic solvent vapors, including their cooling in a layer of heat-accumulating nozzle, passing through a layer of activated carbon, regeneration of coal by passing a gas stream obtained by catalytic oxidation of a gas stream after a heat-accumulating nozzle, which consists in In order to accelerate the regeneration process and U to reduce energy consumption for cleaning, part of the gas stream after regeneration is passed through an additional layer of activated carbon and combined with the gas stream, aemym 20 catalytic oxidation, and after reaching the residual capacity of the main layer of coal, 0.2-0.4 equal, the entire gas stream after regeneration of the base layer is passed through a coal layer dopol25 tional and fed to a catalytic oxidation. thirty Indicators Way Ί ----- Famous Proposed 35 The duration of regeneration of the adsorbent until the concentration of desorbate in the reg 40 non-irrigation flow in front of the fan 0.05 g / m ³ , min 78 52 Duration of electric heating of regenerative 45 current before reactive rum up to 360 ° C, min 57 16 fifty The fraction of the calorific value of the adsorbate is derived 55 is taken from the regeneration circuit of the adsorbent without using the regen stage in the heat balance nonration 0.42 0