DE1519948A1 - Device for the recovery of solvents, in particular per- and trichlorethylene, from air - Google Patents

Description

Bremen, November 23, 1966

Sch / Mk

66,113 AMEG / differential kickback

AMEG mbH Apparate-Maschinen-Entwicklungs-Gesellschaft mbH 28 Bremen, Schwachhauser Heerstraße

Device for the recovery of solvents, in particular per- and trichlorethylene, from air Addendum to patent 1 209 105

The invention relates to a device for the recovery of solvents from air, in particular of per- and trichlorethylene, by inserting a filter chamber with activated charcoal filling into an air delivery channel for those with the solvent Contaminated air for the purpose of adsorbing the solvent from the air onto the activated carbon and by subsequent switching the filter chamber for the purpose of desorption of the solvent from the activated carbon by means of flushing steam with a connection to a dedicated one intended for the desorption steam generator on one side and to a condenser on the other side for the purpose subsequent separation of rinsing steam and solvent by condensation, the steam generator with its steam chamber is directly connected to the filter chamber according to patent 1 209 105.

In the device according to the main patent, activated carbon particles are released from the filter chamber into the vapor space of the Steam generator fall, together with dripping condensate from a condensate trap below the open bottom

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The activated charcoal chamber is collected and diverted.

The present invention is based on the consideration that it is not necessary for proper puncture of the device is to collect the condensate with the falling carbon particles and drain it off, it just has to be for this it must be ensured that no coal particles fall on the heating surfaces of the steam generator. The formation more toxic Phosgene gases are linked to the heating of particles containing solvents to well over 100 ° G. To avoid of these dangerous chemical transformations it is therefore only a question of the direct contact from the Filter chamber falling particles with the high temperature heating surfaces of the Dampferaaager avoid. Although this is also achieved by an arrangement according to the main patent with arranged in the vapor space of the evaporation vessel Superheater and a condensate trap installed between the superheater and the activated carbon chamber can be effectively avoided but according to the invention are generally prevented by any different arrangement in which the or the The heating element of the steam generator is protected against direct contact with particles falling from the filter chamber are arranged. In particular, for the condensate and activated carbon particles falling from the filter chamber a continuous fall space from the activated carbon chamber to the water level of the submersible evaporator, to the Steam generator connected to the bottom of the filter chamber

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lead, which is free of radiator surfaces. This has the advantage that both falling condensate particles as well as activated carbon particles are absorbed by the water of the steam generator without reaching dangerously high temperatures, and that solvent present in the condensate and in the activated carbon particles in the subsequent evaporation process is evaporated with and included in the recovery process.

Preferably, means for maintaining a column of water above the submerged radiator are in the steam generator Steam generator connected to the underside of the filter chamber is provided, so that the water level is above the radiator can form the lower boundary of the fall space.

The fall space between the activated carbon chamber and the water level of the steam generator is expediently part of the Steam space, while in a part of the steam space lying outside the fall space there is a radiator for overheating the purge steam are housed. This superheater can also be installed vertically under the opening of the activated carbon chamber in a manner known per se lie, with the vapor space above the superheater against the fall space through roof-shaped sloping guide surfaces is delimited, on which the falling condensate and the activated carbon particles to the water level of the steam generator be guided. However, the superheater can also be located in a part of the steam space that is to the side of the steam space area, the

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is arranged perpendicularly under the opening of the filter chamber is. In particular with such a lateral arrangement of the superheater and the entire steam generator achieve a particularly simple and economical overall system in that two activated charcoal chambers alternate be switched into the steam flow of a common steam generator. The upper opening is expediently located here of the steam generator between the two case spaces under the two filter chambers.

The arrangement for alternating operation of the two filter chambers in adsorption and desorption operation can be according to the invention with a particularly simple and economical design achieve that between the common Steam condenser and the steam outlet sides of the two filter chambers one on the differential pressure between the Filter chambers-responsive valve device is provided for switching, which opens the steam outlet channel of the filter in adsorption operation to the condenser and at the same time blocks the Dampfaus3aßkanal of the filter in desaptionsbetrieb to the condenser. Further the heat economy can be increased in that the feed water for the steam generator in the condenser for the Purge steam is preheated by switching the cooling system of the condenser into the feed water line for the steam generator is.

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Another solution to the problem underlying the invention is that the steam space of the steam generator on the top of the filter chamber is connected. Through this there is also the advantage that the direction of the steam and the direction of the condensate fall coincide in the filter chamber.

In the drawing, the invention is illustrated using several exemplary embodiments.

Fig. 1 shows a twin arrangement of two alternately in Adsaptinns- and desorption working activated carbon units in a schematic representation,

Fig. 2 is a partial view of an activated carbon unit according to the invention in another embodiment and

Fig. 3 shows a twin arrangement with vapor deposition of the Filter chambers from above.

In the twin arrangement shown in Fig. 1, two activated carbon devices are operated alternately in adsorption and desaption operation in order to recover solvents, in particular per- and trichlorethylene, from the air, such as those found in chemical cleaning systems for metal degreasing, textile cleaning and chemical extraction systems.

909828/1362 ... β

Of the two activated charcoal chambers 1 and 2, one, for example the left-hand chamber 1, works in adsorption mode and the other, for example chamber 2, works in desorption mode. In adsorption operation, the air to be cleaned, from which the solvent is to be recovered, is sucked in with the aid of a fan J, pressed into the left activated carbon chamber via an inlet opening 4a and blown back into the room via an outlet opening 5. During the desorption operation in the right-hand chamber 2, flushing steam is fed from a steam generator β via a steam inlet opening 7b into the right-hand chamber 2 and exits via a line 8b, laden with solvent. This vapor gas mixture is fed via a differential pressure valve 9 and a line 10 to a Ge ^ en-flow condenser 11, from which the liquid mixture of vapor condensate and solvent condensate flows via a line 12 to a separating container 15 for water and solvent. The specific lighter vapor condensate is taken from this separation vessel at a higher point 14 and the specific heavier solvent condensate is taken from the bottom at 15. The steam condensate flows off via a line 16, while the solvent can be fed to a collecting vessel via a line 17 for reuse.

After a certain time, depending on the operating conditions, e.g. B. after an hour or two, in which experience has shown the activated carbon la in the filter chamber 1 so far with the solution

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has enriched means that a continuation of the adsorption would be uneconomical and in the same time in The adsorbed solvent has been rinsed out of the activated carbon 2a in the right pilter chamber to such an extent that a continuation the desorption process would be uneconomical, the roles of the two filter chambers are switched over by switching the left one Chamber swapped from adsorption to desorption and the right chamber from desorption to adsorption mode. For this switchover, flaps 18 and 19 are provided, which pivot about 90 ° counterclockwise for the switchover will. Through the flap 18, the air inlet opening 4b of the chamber 2, which is in the desorption mode in the Chamber 2 was closed, open to the fan 3 and the Air inlet opening 4a to the filter chamber 1 is closed. The steam inlet opening 7a becomes the filter chamber through the flap 19 1, which was closed in the filter chamber 1 during adsorption, opened and the air outlet opening 5 to Chamber 1 closed.

The switching of the steam outlet ducts 8a and 8b of the filter chambers 1 and 2 is carried out automatically by the differential pressure completed between the two chambers, which acts on the valve 9 designed as a differential pressure valve and this valve is adjusted so that the connection of the channel 8b to the line 10 is blocked and the connection of the Outlet channel 8a to line 10 is opened. The differential pressure valve 9 is on the one hand by the pressure of the blower air from Z. B. 0.03 atm, which is now via the connection 8b to the

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Differential pressure valve acts and via the connection channel 8a the pressure of the vapor gas mixture in the filter chamber 1, the is about 0.2 to 0.3 atmospheres, applied.

The feed water for the steam generator 6 is preheated in the condenser 11. For this purpose, the condenser consists of a series of concentrically surrounding tubes. The inner pipe coil is connected to the water line 21 with a shut-off valve 22 and the cooling water with an inlet temperature of about 17 ° C flows through it in countercurrent to the vapor gas mixture to be condensed that flows through the outer pipe coil. The cooling and feed water exits the condenser at a temperature of up to almost 100 ⁰ C and arrives via a feed line 23 with a solenoid valve 24 in the steam generator 6. The solenoid valve 24 is actuated depending on the water level 25 in the steam generator 6, so that in Steam generator above the submerged electric heater 26 a column of water 27 is constantly maintained. For this purpose, a water level controller 28 is connected to the steam generator 6, which controls the solenoid valve 24 via a switching contact actuated by the liquid level.

If the solenoid valve 24 after feeding in water until reaching the desired water level in the steam generator closed, an overflow valve 29 opens a branch line 30 to an overflow to reduce the flow of water in the Capacitor 11 to maintain. The overflowing water

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can be used again. The steam formed in the steam generator is superheated by a superheater J51 in the steam room of the steam generator to about 14o to 150 ⁰ C, so that the desorption takes place with dry superheated steam.

The activated carbon filling la or 2a rests on a perforated plate Ib or 2b, which thus limits the top of the steam space of the steam generator during desorption operation. Active carbon particles that fall from the perforated plate and are contaminated with solvent may, if there are e.g. B. chlorinated or fluorinated hydrocarbons, where dangerous chemical conversions are to be feared, under no circumstances should be heated up to the critical temperature at which the chemical conversion of the used Lcamgsmittel takes place. It must therefore be prevented that these coal particles falling from the filter chamber touch the heating surfaces of the heating elements 26 and Jl in the steam generator. A direct contact with the heating surfaces of the heater 26 iat characterized excluded that this radiator is covered by a water column 27 constantly, so that access into the steam generator coal particles reaching into the heated to about 100 ⁰ C water. Solvent in the coal particles is evaporated together with the water and fed into the recovery process.

There is contact with the heating surfaces of the superheater 31 The illustrated example according to Fig. 1 is excluded by that the superheater ^ l is in a part 32 of the steam space,

909828/1362 ORIGINAL BATHROOM

1 η

the one to the side of the vapor space area 33 * the one vertically below the Perforated plate 2b sets, is arranged. For the activated carbon particles and condensate particles falling from the filter chamber

a continuous fall space 33 is thus created, which extends from the activated carbon chamber to the water level 25 of the submersible evaporator and is free of radiator surfaces. The falling space 33a or 33b located under the perforated plate Ib or 2b is limited at the bottom by a sloping to the steam generator 6 guide surface Ic or 2c, over which condensate and Active carbon particles flow off into the steam generator without coming into contact with the heating elements of the steam generator.

Another embodiment is shown in FIG. 2, in which a steam generator 36 with an immersed heating element 26 and a superheater 31 located in the steam space is provided directly under the perforated plate y \ of an activated carbon chamber 35. As in the first exemplary embodiment, a column of water 27 is constantly maintained over the immersed heating element 26, whereby an effective protection against dangerous heating of falling activated carbon particles is achieved. The superheater 31, located vertically below the passage plate 3 ^ in the steam space of the steam generator, is shielded from the perforated plate 3 * by guide surfaces 37 sloping in the shape of a roof. The steam space of the steam generator is divided into two spaces 38 and 39 by these guide surfaces 37. The space 38 located above the middle of the water level 25 in the steam generator contains the superheater 31, while the steam clearing part 39 which covers this space in a bell-shaped manner

BATH ORIGINAL

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forms a continuous fall space for condensate and activated carbon particles, from the perforated plate ^ 4 to the water level 25 is enough.

Fig. J shows an embodiment in which the vapor space of the Steam generator 40 is not connected to the bottom, but to the upper oil of the filter chambers, while the Air to be cleaned flows through the filter chambers from bottom to top. Corresponding parts are provided with the same reference numerals as in Fig. 1. Falling condensate and Activated carbon particles can flow off via the condenser 11 to the separating vessel 13. Activated carbon particles can also be darch hold back a filter or trap that is switched on to the condenser. The solvent adhering to them is carried along by the steam and fed to the condenser and separation tank.

There are still many modifications within the scope of the invention and other designs possible. In particular, the continuous fall spaces for the activated carbon and condensate particles instead of the water level of the steam generator lead to another point, for example to a vessel, which is switched on behind the solenoid valve 24 in the feed line of the steam generator.

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... 12

Claims (11)

Claims 1. device for the recovery of solvents from air, especially of per- and trichlorethylene, by switching on a filter chamber with activated charcoal filling into one Air delivery channel for the air contaminated with the solvent for the purpose of adsorbing the solvent from the air the activated carbon and by subsequent switching of the filter chamber for the purpose of desorption of the solvent from the Activated carbon by means of purging steam with connection to a steam generator specially provided for desorption on one side Side and to a condenser on the other side for the subsequent separation of purge steam and solvent by condensation, whereby the steam generator with its steam chamber is connected directly to the filter chamber is (according to patent 1 209 105), characterized in that the heating element (s) (9 »H) of the steam generator (6) are arranged protected against direct contact with particles falling from the filter chamber (2). 2. Apparatus according to claim 1, characterized in that for the falling from the filter chamber and condensate Activated carbon particles a continuous fall space (5Yes, 53b Fig. 1 and 39 Fig. 2) from the activated carbon chamber to Water level (25) of the submersible evaporator connected to the underside of the filter chamber (6 Fig. 1 and 37 Fig. 2) which is free of radiator surfaces. 909828/1362 '"^1J> 3 · Device according to claim 2, characterized in that Means (28) for maintaining a water column (25) above the heating element (27) on the underside of the filter chamber connected evaporator vessel are provided and that the water level above the immersed radiator (26) represents the lower pallet space limit. 4. Apparatus according to claim 2, characterized in that the fall space (33, 39) only part of the vapor space between Water level (25) of the evaporation vessel (6, 36) and Occupies activated charcoal chamber, and that in the part (32, 38) of the vapor space lying outside the fall space a known steam superheater (31) is housed. 5 · Device according to claim 4, characterized in that the superheater (3I) is in a known manner vertically below the strainer (34) of the filter chamber (35), and that the steam space (38) above the superheater (31) is delimited from the fall space (39) by roof-shaped sloping guide surfaces (37). β. Device according to claim 4, characterized in that the The superheater is located in a part of the steam chamber that is to the side of the steam chamber area (32) and that perpendicularly under the strainer (Ib, 2b) lays, is arranged. 7. Apparatus according to claim 1 to 6, characterized in that two activated charcoal chambers (1, 2) alternately connected to the steam flow of a common evaporation vessel (6) 909828/1362 will. _k -H- 8. Apparatus according to claim 7> characterized in that the opening of the steam generator (6) is between the fall spaces (33a, 33b) lies under the two Pilterkammerη (1, 2). 9. Apparatus according to claim 7 *, characterized in that between the common steam condenser (11) and the steam outlet sides of the two filter chambers (1, 2) a to the differential pressure between the filter chambers responsive valve device (9) is provided, which the steam outlet channel (8a) of the filter (1) in desorption operation to the condenser (11) opens and at the same time the steam outlet channel (8b) of the filter (2) in adsorption operation to the condenser closes. 10. Apparatus according to claim 1 to 9, characterized in that the feed water for the steam generator (6) in the condenser (11) is preheated for the purge steam by inserting the cooling system of the condenser into the feed water line (23) is switched on for the steam generator. 11.Vorrichtung according to claim 1, 7 * 9 and 10, characterized in that the steam space (38) of the steam generator (6) is connected to the top of the filter chamber (^ 4 ) (Fig. 3). 909828/1362 ... Delimitation of the scope of protection: An arrangement with a superheater arranged in the vapor space of the evaporation vessel and between the heater and the The condensate trap attached to the activated carbon chamber is the subject of the main patent. 909828/1362 Blank page