DE102005048298B3 - Rotary bed adsorber for purification of air contaminated with low concentration of organics, uses partial recycle of spent regeneration gases to increase concentration of impurity in final combusted foul gas stream - Google Patents

Abstract

Continuous or semi-continuously operated adsorption bed is contained in a cylindrical housing which rotates, with sealing contact, between pairs of outlet and inlet ducts, such that as one sector (8) is adsorbing, a second sector (18) is being cooled, and a third sector is purging with a mixture of hot air and desorbed gas, viz. 150-250[deg]C and up to 10% recycled gas. An independent claim is included for an adsorber installation for purifying organics polluted air. To prevent thermal damage to seals, the regeneration air connection port may be divided to deliver hot air with an insulating flow of cool air (24) in the vicinity of the seal surface (claimed). The adsorber rotates about an axis (5), in an anti-clockwise direction, so that the adsorbing sector (8) is lined up with foul gas feed (6) and purified air discharge line (16), the regeneration sector (29) is lined up with hot air feed (28) and desorbed gas outlet (31), and the previously regenerated sector (18) is cooled with atmospheric air (21) which is then (26) blended with after-burner combustion gas, under control of a throttling valve (66), and further heated to provide regeneration purge gas.

Description

The The invention relates to a process for the purification of organic Pollutants laden exhaust air and a system for carrying out the Method according to the preamble of claim 14.

Out DE 197 16 877 C1 It is already known to clean exhaust air laden with organic pollutants with an adsorptive cleaning system and an afterburner. The cleaning system comprises an adsorbent-containing cylindrical body which is rotated about its cylinder axis and oppositely disposed on both sides in sectors connections for the passage of the exhaust air to be cleaned from a crude gas line into a clean gas line, for the passage of cooling air from a Kühlluftaufuhrleitung in a cooling air discharge line and for the passage of hot air for desorption of the adsorbed pollutants with a hot air supply line in a pollutant line to the outlet of the exhaust air with the desorbed pollutants. The post-combustion system includes a combustion chamber for combustion of the desorbed pollutants, wherein for heating the hot air, a portion of the hot combustion chamber air is supplied to a mixing chamber.

by virtue of the high flow rate through a suction fan are already in the cooling zone Pollutants desorbed, so due to the heating in the mixing chamber through the hot one Combustion chamber air from the combustion chamber discharge line and the resulting hot air in the hot gas supply line, fed to the desorption zone will, the hot air at least partially from a part of the exhaust air with the desorbed Pollutants, which after heating by the part of the hot combustion chamber air to the connection to the hot air inlet is attributed to the desorption of the adsorbed pollutants.

In order to be with the known system by the absorptive cleaning system the pollutants concentrated. When the concentration of pollutants the exhaust air to be cleaned does not have a certain minimum concentration falls short of, can do with it the pollutants of the post-combustion plant in one concentration supplied be that their combustion no additional energy supplied must, so the post-combustion plant be operated autothermally can.

The maximum possible Concentration of the pollutants is in the known method However, essentially limited by the fact that with the necessary for this small desorption air stream a complete regeneration (> 90%) of the adsorbent not possible is. This reduces the capacity. The cleaning performance and the enrichment factor of the adsorptive cleaning system are so in opposite directions, that is called Cleaning performance decreases with increasing enrichment factor, so The higher the concentration of pollutants in the post-combustion plant supplied Exhaust air opposite the concentration of pollutants in the exhaust air to be cleaned is. At low pollutant concentration in the exhaust air to be cleaned Therefore, additional energy must be supplied in the known method; In addition, the cleaning efficiency is lower than desired.

task The invention is, even at very low pollutant concentration in the exhaust air to be cleaned, the total energy demand of such a system without impairment the high cleaning efficiency and without increasing the equipment cost to reduce substantially.

This is inventively with the achieved in claim 1 method. In the claims 2 to 13 are preferred embodiments the method according to the invention specified. In claim 14 is a preferred system for carrying out the inventive method characterized by the claims 15 to 23 in an advantageous Way is further developed.

at The adsorptive cleaning system will be more than half of the Cross-section of the adsorbent-containing cylindrical Body of flows through polluted exhaust gas, while in a smaller segment the hot air for desorption of the adsorbed Pollutants flows. By the rotation of the cylindrical body and the sector-shaped connections to Supply and removal of the individual gases to and from the body relative to each other a continuous operation is possible. That is, at the Cleaning equipment can rotate while the cylindrical body the sector-shaped connections do not move or can the connections turn while the cylindrical body is arranged stationary is. In this case, the embodiment is described below, preferably at the cylindrical body turns, so forms a rotor.

According to the invention, a portion of the exhaust air with the adsorbed pollutants is not supplied to the post-combustion system, but diverted to form at least a portion of the hot air after heating by a portion of the combustion chamber air. According to the invention thus a correspondingly increased amount of hot air to the cylindrical body guided. At the same time, the hot air in addition pollutants, so that emerges from the cylindrical body, an exhaust air stream with a higher pollutant concentration.

While at high rotor speed and thus high capacity of the rotor complete regeneration of the adsorbent at the same time high accumulation of pollutants in the post-combustion system supplied exhaust air is not yet possible, because the transferred heat by the amount of heat in the hot air stream is limited, the only of the hot air volume flow and the temperature depends can according to the invention, as a Part of the exhaust air with the desorbed pollutants to the connection for hot air intake attributed to the desorption of the adsorbed pollutants, in this ratio more Energy can be used for desorption. This increases the possible concentration of the Pollutants in the post-combustion system supplied exhaust air and the total energy consumption of the system decreases.

The increase of the enrichment factor allows the autothermal operation of the system according to the invention at a constant Cleaning performance and low investment costs.

Preferably be at least 10%, in particular 10 to 60% of the throughput of Exhaust air with the desorbed pollutants to the connection to the hot air inlet recycled.

Of the Throughput of the exhaust air with the desorbed pollutants in the post-combustion plant is preferably at least 4%, in particular 4 to 20% of the throughput of the to be cleaned Exhaust air through the cylindrical body.

to Return of the Exhaust air with the desorbed pollutants have in particular two variants proved suitable. After a variant becomes the exhaust air with the desorbed pollutants from the outlet the cylindrical body with a fan fed to the post-combustion plant, wherein the part of the exhaust air with the adsorbed pollutants, the for hot air intake is attributed between the blower and diverted to the post-combustion plant. One is enough Return line with a throttle valve off to a partial flow of concentrated Attributed exhaust air and so that the amount of heat transferred to the adsorbent to increase, without the inlet temperature or in the post-combustion plant to increase the volume flow to be treated.

To the other variant are at the outlet of the exhaust air with the desorbed Pollutants instead of a sector-shaped connection two sector-shaped connections, wherein the outgoing from the first port exhaust air to the port for the entry of hot air is returned to the desorption of the adsorbed pollutants and from the second Connection exiting exhaust air is fed to the post-combustion system. During the first connection to the connection to the inlet of the exhaust air to be cleaned is adjacent, the second port is the connection to the cooling air passage adjacent.

There the rotor rotates from the first to the second port is the exhaust air, which enters the first port, less loaded and cooler than the exhaust air that enters the second port where the adsorbent from the hot air is heated up to the maximum. After this variant, it becomes a relatively cool, weak loaded part of the exhaust air over a return line returned and for the formation of hot air used. In the return line is preferably a fan intended.

By the repatriation of the cool little loaded Partial current over the blower is the enrichment increased, without reducing the cleaning performance, because so a larger amount of heat can be transferred to the rotor within the desorption sector. In order to Is it possible, even at high rotor speed, which is directly proportional to the capacity of the rotor is still complete to desorb.

Both Variants can also executed together become.

While the to be cleaned exhaust air and the cooling air the cylindrical body flow through in one direction, flows the hot air for the desorption of the adsorbed pollutants in opposite Direction through the cylindrical body.

Around the part of the exhaust air with the desorbed pollutants, which led to the Connection to the hot air inlet is attributed to warm with the combustion chamber air, can be a mixer or a heat exchanger be provided. When a heat exchanger occurs the combustion chamber air as cooled Clean gas.

When cooling air can use ambient air or a part of the exhaust air to be cleaned become. The heated after passing through the cylindrical body cooling air is with the part of the exhaust air with the desorbed pollutants, the Connection to the hot air inlet is attributed united, wherein when using a heat exchanger for heating the hot air the union preferably before entering the heat exchanger he follows.

For sealing the sector-shaped An Closures to the relatively rotatable cylindrical body seals are used, which have a limited temperature resistance of eg up to 250 ° C. They thus withstand, for example, heated to 150 to 200 ° C hot air for the desorption of pollutants. Although most of the pollutants are desorbed at this temperature in order to remove a residue of higher-boiling pollutants, according to the invention the sector-shaped connection for hot air inlet is preferably in an inner region which is at a distance from the connection to the cooling air passage and at a distance from the connection to the clean air outlet is divided, and divided into the outer regions, which are adjacent to the connection to the cooling air passage and the connection to the clean air outlet. The inner area can thus be supplied with a hot air, which is heated to a higher temperature than the hot air supplied to the outer areas, without damaging the seals, the one outer area of the connection to the cooling air passage and the other outer area of the connection to Disconnect the clean air outlet. Thus, the temperature of the hot air supplied to the inner region may be from 20 to 150 ° C, preferably 30 to 80 ° C, above the temperature of the hot air supplied to the outer regions.

The supplied to the inner area Hot air can be over one Bypass pipe with a heater connected to the hot air supply pipe is connected, supplied become. Also, the inner region combustion chamber air can be supplied.

For the inner one Area can be a sector-shaped Connection may be provided, which between the two seals and at a distance from the two seals of the sector-shaped connection is arranged, to which the hot air supply line connected.

Around to prevent the hot gas can reach from the inner region to the seals, the hot air supplied to the inner area lower pressure than the hot air supplied to the outer areas.

By the to the hot air supply line Connected bypass line with a heater on the sector-shaped Connection is connected, which between the two seals of the sector-shaped Connection to which the hot gas supply line is connected, to which a "bake-out", for example at 250 to 350 ° C can be performed, without the seals having the e.g. at 250 to 350 ° C hot air the bypass line in contact come. For desorption of high-boiling pollutants in the "bake-out" operation of the cylindrical bodies, without being exposed to the exhaust air to be cleaned, with a speed rotated, which is lower than the exhaust air cleaning operation.

For example For example, the speed of the exhaust air cleaning operation can be three to six revolutions per minute Hour, but only in "bake-out" operation one to three revolutions per hour.

below the invention with reference to the accompanying drawings by way of example explained in more detail. It shows:

1 a schematic view of the cleaning system according to a first embodiment;

2 and 3 a plan view of the side of the cylindrical body with the sector-shaped connections to the outlet of the clean air after adsorption of the pollutants, the exit of the cooling air and the entry of the hot air for desorption of the adsorbed pollutants or to enter the exhaust air to be cleaned, the entry of the cooling air and Outlet of the exhaust air with the desorbed pollutants of the cleaning system after 1 ;

4 a schematic view of a cleaning system according to another embodiment and

5 a plan view of the side of the cylindrical body with the sector-shaped connections for the entry of the exhaust air to be cleaned, the entry of the cooling air and the outlet of the exhaust air with the desorbed pollutants of the cleaning system after 4 ,

According to 1 the system consists of an adsorptive cleaning system 1 and an afterburner 2 ,

The adsorptive cleaning system 1 has a cylindrical body 3 on top of that with an adsorbent 4 coated or filled and about an axis 5 is offset by a motor, not shown in slow rotation.

The cylindrical body 3 is via a crude gas line 6 to be cleaned, laden with organic pollutants exhaust air with a blower 7 fed. Between the blower 7 and the cylindrical body 3 is in the crude gas line 6 a shut-off device 9 intended. The crude gas line 6 is connected to a port, not shown, which is one of the adsorption sector 8th corresponding circular sector shape, wherein the edge region of the terminal with a seal 10 . 11 opposite the gas-permeable side or side wall 12 of the body 3 is sealed, as in 2 Darge provides.

A corresponding segmental connection in the adsorption sector 8th is opposite, so on the other side or side wall 13 of the cylindrical body 3 arranged, which is likewise gas-permeable. At this connection, opposite the side wall with the gaskets 14 . 15 is sealed ( 3 ) is the clean gas line 16 connected to a fireplace 17 leads.

Another sector-shaped connection is in the area of the cooling sector 18 provided, which is opposite the side wall 12 of the body 3 on the one hand with the seal 10 and on the other hand with a seal 19 is sealed ( 2 ). This connection to the refrigeration sector 18 the cooling air is via a pipe 21 fed with a filter 22 and a shut-off device 23 between filters 22 and cylindrical body 3 is provided.

Instead, the cooling air supply line may also be through a bypass line 24 be formed, which is the crude gas line 6 with the connection to the cooling sector 18 combines. In this case, the seal located at the inlet of the main stream ( 10 ) account for the cooling sector.

A corresponding circular sector-shaped connection is in the area of the cooling sector 18 on the other side 13 of the cylindrical body 3 arranged and opposite the same by the seal 15 and a seal 25 sealed ( 3 ). At this connection is the cooling air discharge line 26 connected to a heat exchanger 27 leads.

For desorption of the adsorbed pollutants is a hot gas supply line 28 provided, which leads to a connection, not shown, on the side wall 13 of the cylindrical body 3 which leads to the desorption sector 29 corresponding circular sector shape and with respect to the side wall 13 through the seal 14 and the seal 25 is sealed ( 3 ). A corresponding unillustrated sector-shaped connection in the desorption sector 29 is on the other side wall 12 of the cylindrical body 3 arranged and opposite the side wall 12 with the seals 11 and 19 sealed. To the connection on the side wall 12 in the field of desorption 29 is a pollutant line 31 connected a blower 32 and to a post-combustion plant 2 leads.

While the cylindrical body 3 rotates, are the connections to the entry of the exhaust air to be cleaned and the outlet of the clean air, the entry of the hot air for desorption and the exit of the exhaust air with the desorbed pollutants and the passage of the cooling air firmly.

The post-combustion plant 2 has two over a combustion chamber 34 with a burner 35 connected chambers 36 . 37 on, which are each filled with a heat storage mass.

Every chamber 36 . 37 is via a shut-off or switching organ on the one hand with the pollutant line 31 and on the other hand with a clean gas line 41 connectable to the fireplace 17 leads. Between the shut-off devices 38 . 39 and the fireplace 17 is in the clean gas line 41 a valve 42 intended.

From the combustion chamber 34 is via a combustion chamber air discharge line 43 a partial flow of the 700 to 900 ° C hot combustion chamber air from the combustion chamber 34 subtracted and the heat exchanger 27 supplied, wherein the cooled combustion chamber air via the line 44 the clean gas line 16 is supplied. The proportion of over the combustion chamber air supply line 43 the heat exchanger 27 supplied combustion chamber air is via a control valve 45 in the combustion chamber air discharge line 43 set.

To the temperature of the combustion chamber air in the combustion chamber air discharge line 43 to be able to degrade is a bypass line 46 provided, which the combustion chamber air discharge line 43 with the clean gas line 41 combines. Another valve 47 is between bypass line 46 and the heat exchanger 27 in the combustion chamber air discharge line 43 provided, further a valve 48 downstream of the bypass line 46 between combustion chamber air discharge line 43 and clean gas line 41 ,

To the pollutant line 31 is between the blower 32 and the shut-off devices 38 . 39 a return line 49 connected to the cooling air discharge line 26 connected, whereby the cooling air and a part of the exhaust air with the desorbed pollutants together the heat exchanger 27 is supplied. When passing through the heat exchanger, the mixture formed from cooling air and exhaust air is heated to eg 150 to 250 ° C and as a hot gas via the hot gas supply line 28 the desorption sector 29 of the cylindrical body 3 fed.

About the bypass line 46 For example, by supplying clean gas from the clean gas line 41 to the combustion chamber air in the combustion chamber air supply line 43 the heat exchanger 27 an air at a temperature of for example 450 ° C are supplied. The valve 48 serves to remove too much hot clean gas. With the throttle valve 42 the pressure is adjusted so that the mixture of clean gas through the bypass line 46 is supplied, and the combustion chamber air from the Brennkammerluftabfuhrleitung 43 with the desired throughput of pure gas tung 16 is supplied.

The trained on the example as three-way valves shut-off 38 . 39 connected line 51 connected to the pollutant line 31 connected and with a shut-off device 52 is provided, which serves when switching the post-combustion system 2 escaping peak of pollutant-containing air of the pollutant line 31 supply.

With a bypass line 53 on the one hand to the Brennkammerluftabfuhrleitung 43 and on the other hand to the hot gas supply line 28 connected and with a shut-off or throttle 54 is provided, the hot gas in the hot gas supply line 28 be heated to a higher temperature in order to desorb higher-boiling substances can.

In the return line 49 is a throttle valve 66 arranged to reduce the proportion of exhaust air with the desorbed pollutants in the return line 49 to be able to adjust. For example, 50% of the exhaust gas flow in the pollutant line 31 the post-combustion plant 2 and 50 the return line 49 be supplied.

To the hot gas supply line 28 is a bypass line 55 with a shut-off device 56 and a heater 57 connected. The bypass line 55 is doing an in 3 schematically illustrated internal segment-shaped connection 58 connected, which between the two seals 14 and 25 and is spaced from them. The connection 58 can thereby by at a distance from the side wall 13 arranged baffles may be formed. The with the heater 57 heated to a higher temperature hot air is thus from the seals 14 and 25 kept away so as not to damage them. For this, the points the connection 58 In addition, hot air supplied to a lower pressure than the hot air, via the hot gas supply line 28 the desorption sector 29 outside the terminal 58 is supplied. The lower pressure is through the throttle valve 56 set.

With the over the bypass line 57 supplied hot air can be a "bake-out" of the adsorbent 4 of the cylindrical body 3 be carried out, wherein in contrast to the emission control mode in the "bake-out" operation of the cylindrical body 3 over the crude gas line 6 no exhaust gas is supplied and the cylindrical body 3 rotates more slowly.

About the line 59 with the obturator 60 can the chambers 36 . 37 over the pollutant line 31 and the valves 38 . 39 Fresh air is supplied to the post-combustion plant 2 to approach.

The embodiment according to 4 is different from the after 1 essentially in that the return line 49 in 1 through the return line 61 replaced, which is a blower 62 and a throttle valve 63 having. The return line 61 is like the return line 49 with its one end to the cooling air discharge line 26 connected.

With its other end is the return line 61 to a circular sector-shaped connection 64 connected, as in 5 shown in the desorption sector 29 on the side wall 12 of the cylindrical body 3 is arranged.

The sector-shaped connection 64 is at the of the refrigeration sector 18 opposite side of the desorption sector 29 arranged. By rotation of the cylindrical body 3 in the direction of the arrow 65 and by the high heat capacity of the body 3 turns on the sidewall 12 about the desorption sector 29 In operation, a temperature profile, which at the seal 11 between adsorption sector 8th and desorption sector 29 starts with the raw gas temperature and to seal 19 to the cooling sector 18 increases.

By the sector-shaped connection 64 in the desorption sector 29 Thus, a little loaded, relatively cool partial flow with the blower 62 recycled to increase the accumulation of pollutants, without reducing the cleaning performance, as a greater amount of heat on the cylindrical body 3 within the desorption sector 29 can be transferred. This makes it possible, even at high speed of the cylindrical body 3 which is directly proportional to the capacity of the adsorbent 4 is yet to completely desorb this.

The system works as follows:
The contaminated with pollutants exhaust air is via the crude gas line 6 the adsorption sector 8th of the cylindrical body 3 fed, in which the pollutants are adsorbed. The cleaned exhaust air flows through the clean gas line 16 in the fireplace 17 ,

The cylindrical body 3 turns continuously according to the arrow 65 around the axis 5 so that the pollutant-laden adsorbent 4 in the cylindrical body 3 from the adsorption sector 8th in the desorption sector 29 is rotated while the desorption sector 29 in the refrigeration sector 18 and the refrigeration sector 18 in the adsorption sector 8th passes to adsorb pollutants from the exhaust air to be cleaned again.

About the line 21 is either ambient air as cooling air or over the line 24 a partial flow of the exhaust air to be cleaned as cooling air to the cooling sector 18 fed to the straight with hot air from the hot air supply line 28 desorbed desorption sector 29 to cool. After flowing through the cooling sector 18 The then heated cooling air through the cooling air discharge line 26 to the heat exchanger 27 guided, over the combustion chamber air discharge line 43 hot air from the combustion chamber 34 is fed to the heat exchange, as clean air over the line 44 into the clean air line 16 flows.

The hot air for the desorption of pollutants in the desorption sector 29 on the one hand from the heated cooling air in the cooling air discharge line 26 and on the other hand formed from the partial flow of the exhaust gas with the desorbed pollutants, which via the return line 49 ( 1 ) or the return line 61 ( 4 ) is supplied. The mixture of heated cooling air and the partial exhaust gas flow is with the heat exchanger 27 heated and over the hot air supply line 28 the desorption sector 29 fed.

The loaded by desorption with high pollutant concentration exhaust gas passes from the pollutant line 31 with the fan 32 over the valves 38 . 39 in one of the two chambers 36 . 37 the post-combustion plant 2 , The heat storage mass in the relevant chamber 36 . 37 , which had been heated in the forthcoming cycle, heats the exhaust gas containing the desorbed pollutants, whereupon the desorbed pollutants in the combustion chamber 34 to be burned. In this case, the combustion can be carried out autothermally, that is, the burner according to the invention due to the high pollutant concentration of the exhaust gas 35 does not normally need to be turned on during the emission control operation. With the hot combustion chamber air, the heat storage mass of the other chamber 36 . 37 heated, causing largely cooled clean gas in the clean gas line 41 arrives. The chambers 36 . 37 alternately eg every one to three minutes by switching the valves 38 . 39 either to the pollutant line 31 or the clean gas line 41 connected.

To avoid getting out of the chamber 36 . 37 who last over the line 31 has been charged with the exhaust gas with the desorbed pollutants, after switching that in this chamber 36 . 37 contained exhaust gas with the desorbed pollutants in the clean gas line 41 is reached, just before the start of switching the valves 38 . 39 by closing the valve 33 and opening the valve 52 over the line 51 the chamber 36 . 37 supplied only slightly polluted exhaust gas.

Claims (23)

Process for the purification of exhaust air laden with organic pollutants, with an adsorptive purification plant ( 1 ) with at least one an adsorbent ( 4 ) cylindrical body ( 3 ) around its cylinder axis ( 5 ) and opposite on both sides ( 12 . 13 ) relative to the cylindrical body ( 3 ) arranged in sectors connections for the passage of the exhaust air to be cleaned from a crude gas line ( 6 ) in a clean gas line ( 16 ), for the passage of the cooling air from a cooling air supply line ( 21 . 24 ) in a cooling air discharge line ( 26 ) and for the passage of hot air for the desorption of the adsorbed pollutants from a hot air supply line ( 28 ) into a pollutant line ( 31 ) to exit the exhaust air with the desorbed pollutants, with an afterburner ( 2 ) with a combustion chamber ( 34 ) for combustion of the desorbed pollutants, wherein for heating the hot air, a portion of the hot combustion chamber air of a heating device ( 27 . 57 ) is supplied and the heated hot air at least partially consists of a portion of the exhaust air with the desorbed pollutants, in addition to the pollutant ( 31 ) to a return line ( 49 . 61 ) in turn to the Kühlluftabführleitung ( 26 ) and a throttle valve ( 66 ) in the return line ( 49 . 61 ) is arranged to adjust the part of the exhaust air with the desorbed pollutants. Method according to claim 1, characterized in that that at least 10% of the exhaust air with the desorbed pollutants to the connection to the hot air inlet to be led back. A method according to claim 1 or 2, characterized in that the throughput of the exhaust air with the desorbed pollutants in the post-combustion plant ( 1 ) at least 4 wt .-% of the throughput of the exhaust air to be cleaned by the cylindrical body ( 3 ) is. Method according to one of the preceding claims, characterized in that the exhaust air with the desorbed pollutants with a blower ( 32 ) from the exit from the cylindrical body ( 3 ) of the post-combustion plant ( 2 ) is supplied and the part of the exhaust air with the desorbed pollutants, which is returned to the hot air inlet, between the blower ( 32 ) and the post-combustion plant ( 2 ) is diverted. Method according to one of the preceding claims, characterized in that two sector-shaped connections are used at the outlet of the exhaust air with the desorbed pollutants instead of a sector-shaped connection, wherein the from the first port, which is adjacent to the connection to the inlet of the exhaust air to be cleaned exiting Exhaust air is recycled with the desorbed pollutants to the connection to the inlet of the hot air for the desorption of the adsorbed pollutants and the exiting from the other terminal Ab air adjacent to the cooling air passage of the post-combustion plant ( 2 ) is supplied. A method according to claim 1, characterized in that the part of the exhaust air with the desorbed pollutants, which is returned to the connection for the hot air inlet, with a heat exchanger ( 27 ) is heated by the combustion chamber air. Method according to one of the preceding claims, characterized in that the cooling air after passing through the cylindrical body ( 3 ) is combined with the part of the exhaust air with the desorbed pollutants, which is returned to the connection to the hot air inlet, combined. A method according to claim 6 and 7, characterized in that the cooling air with the part of the exhaust air with the desorbed pollutants before entering the heat exchanger ( 27 ) is united. Method according to one of the preceding claims, characterized characterized in that for the desorption of higher boiling pollutants the sectorial Connection to the hot air inlet in an inner area at a distance from the connection to the cooling air passage and hot air is supplied at a distance from the connection to the clean air outlet, to a higher temperature heated is as in outer areas of the sector-shaped Connection to the hot air inlet, the connection to the cooling air passage and the connection to the clean air inlet are adjacent. Method according to claim 9, characterized that the hot air supplied to the inner area has a temperature of more than 20 ° C above the the outer areas supplied hot air having. Method according to claim 9 or 10, characterized that the hot air supplied to the inner area has a lower pressure has as the outer areas supplied Hot air. A method according to claim 9, characterized in that for the desorption of high-boiling pollutants instead of the emission control operation, a "bake-out" operation is carried out, in which without acting on the cylindrical body ( 3 ) to be cleaned with the exhaust air to the inner region of the sector-shaped connection for hot air inlet hot air at a temperature of more than 250 ° C is supplied. A method according to claim 12, characterized in that the rotational speed of the cylindrical body ( 3 ) relative to the sector-shaped terminals in the "bake-out" operation is lower than the exhaust air purification operation. Plant for carrying out the method according to one of the preceding claims, with an adsorptive cleaning system ( 1 ) with at least one an adsorbent ( 4 ) cylindrical body ( 3 ) around its cylinder axis ( 5 ) is rotatable and opposite on both sides ( 12 . 13 ) relative to the cylindrical body ( 3 ) arranged in sectors connections for the passage of the exhaust air to be cleaned from a crude gas line ( 6 ) in a clean gas line ( 16 ), for the passage of the cooling air from a cooling air supply line ( 21 . 24 ) in a cooling air discharge line ( 26 ) and for the passage of hot air for the desorption of the adsorbed pollutants from a hot air supply line ( 28 ) into a pollutant line ( 31 ) to exit the exhaust air with the desorbed pollutants, and with an afterburner ( 2 ), at least two via a combustion chamber ( 34 ), filled with a heat storage mass chambers ( 36 . 37 ), wherein in the pollutant line ( 31 ) a blower ( 32 ), each chamber ( 36 . 37 ) with the pollutant line ( 31 ) and a clean gas line ( 41 ) and to the combustion chamber ( 34 ) a combustion chamber air discharge line ( 43 ) is connected to the hot air heating, characterized in that a return line ( 49 . 61 ) for returning a portion of the exhaust air with the desorbed pollutants to the hot air supply line ( 28 ) and between the return line ( 49 . 61 ) one to the combustion chamber air supply line ( 43 ) connected heater ( 27 . 57 ) is provided for heating the supplied part of the exhaust air with the desorbed pollutants. Plant according to claim 14, characterized in that the return line ( 49 ) between the blower ( 32 ) and the post-combustion plant ( 2 ) to the pollutant line ( 31 ) connected. Plant according to claim 15, characterized in that a throttle valve ( 66 ) in the return line ( 49 ) is provided. Plant according to one of Claims 14 to 16, characterized in that the cylindrical body ( 3 ) at the outlet of the exhaust air with the desorbed pollutants instead of a port two, having ports, wherein at the one port, which is adjacent to the connection to the cooling air passage, the pollutant line ( 31 ) and at the other connection the return line ( 61 ) connected. Plant according to claim 17, characterized in that in the return line ( 61 ) a blower ( 62 ) is provided. Installation according to claim 14, characterized in that the heating device by a heat exchanger ( 27 ) is formed. Installation according to one of the preceding claims, characterized in that the Kühlluftabführleitung ( 26 ) to the return line ( 49 . 61 ) connected. Installation according to one of the preceding claims, characterized in that seals ( 10 . 11 . 14 . 15 . 19 . 25 ) for sealing the connections with respect to the relatively rotatable cylindrical body ( 3 ) are provided to the hot air supply line ( 28 ) and / or combustion chamber discharge line ( 43 ) a bypass line ( 55 ) connected to a ( 58 ), which at a distance from the two seals ( 14 . 25 ) of the connection is arranged at which the hot air supply line ( 28 ) connected. Plant according to claim 21, characterized in that the to the Heißluftzuführleitung ( 28 ) connected bypass line ( 55 ) a heating device ( 57 ) having. Plant according to claim 21 or 22, characterized in that the combustion chamber air supply line ( 43 ) over the line ( 53 ) and the throttle ( 54 ) directly to the bypass line ( 55 ) or to the hot air supply line ( 28 ) connected.