DE3324123A1 - Apparatus for the utilisation of the heat from flue gases from furnaces - Google Patents

Abstract

A spraying apparatus (1) serves to purify the flue gases and has a treatment chamber (3) in which a disc arrangement (17) acting as an axial fan is arranged in a rotating manner, the discs of which can be impinged by liquid from a liquid bath (22) in such a manner that a liquid coating detaching outwardly in the form of an annular spraying zone is formed on the discs (19). The washing liquid contained in the liquid bath (22) is continuously neutralised by, for example, conducting constantly sprayed detergent away from the treatment chamber (3) by means of a collecting part (39) and adding a neutralising agent to the detergent in a reaction vessel (31). The liquid is then again (transfer line 34) passed into the liquid bath (22). A heat exchanger (30) is arranged inside the spraying zone, which heat exchanger is correspondingly continuously washed. As a result, the heat exchanger (30) can be manufactured from a comparatively corrosion-susceptible material, although the flue gases under some circumstances have high proportions of corrosive impurities. <IMAGE>

Description

The invention relates to a device for utilizing the heat of flue gases from combustion systems, such as Boiler and the like, with a heat exchanger exposed to the flue gases for heating one flowing through the same Heat transfer medium.

So far, the heat exchangers of such devices because of the often very aggressive pollutants contained in the flue gases from very expensive corrosion-resistant Materials are made. So far, this has made full use of the heat content, which is desirable in itself often prevented by smoke gases.

The object of the invention is to create a device which allows the residual heat of the flue gases to be used economically even in smaller firing systems.

This object is achieved in that the heat exchanger is in a treatment room through which the flue gases pass a spray device - serving as a flue gas scrubber - with a heat exchanger arranged in the treatment room is accommodated completely with sprayed washing liquid acting on the spray zone in which in the smoke gases entrained pollutants are absorbed by the sprayed liquid, and that the sprayed Liquid can be fed to a reservoir or reservoir supplying the spray zone, to which a device is assigned to neutralize or monitor the acidity of the collected washing liquid.

The invention is based on the general idea that the scrubbing liquid of flue gas scrubbers, which in the With a view to reducing the pollution of the environment with acid-forming exhaust gases, they are always desirable

a neutralizing agent is to be added to the one hand, long service lives of the used Washing liquid and, on the other hand, an introduction of used washing liquid into the sewage network to enable; this constantly neutralized washing liquid is now used to power the heat exchanger to protect against the corrosive effects of the flue gas by keeping the heat exchanger continuously connected to the sufficiently neutral washing liquid is sprayed and TO is washed off with it. This allows the heat exchanger from comparatively at risk of corrosion Manufacture materials.

Preferred embodiments of the invention, like them The subject of the claims are explained below with reference to the drawing. They show Figures with regard to the partially sectioned spray device corresponding Arrangements with different, exemplary devices for neutralizing the sprayed Liquid, namely shows

Fig. 1 shows a first embodiment in which the

Spray liquid is constantly partially renewed, Fig. 2 shows a second embodiment in which the

Spray liquid continuously discharged from the spray device and with neutralizing agent is returned offset, and

FIG. 3 shows an arrangement similar to FIG. 2,

but with the destruction of the resulting sludge.

According to FIG. 1, the spray device, designated as a whole by 1, is used, for example, for cleaning of flue gases from a boiler, not shown, or the like. serves, a substantially cylindrical Housing 2, the interior of which is divided into a treatment space 3 and an annular space 4 surrounding the same is. A cylindrical jacket 5 open at the bottom serves to separate the annular space 4 from the treatment space 3, whose upper end is welded to an annular plate 6, which in turn with its outer edge attached to an annular bead arranged in the peripheral wall of the housing 2 (by welding or the like.) is. The inner edge of the annular plate 6 is connected to a cylindrical pipe part 7, which extends up to an annular end wall 8 of the housing 2 connected to the tubular part 7 and forms the inlet opening of the treatment space 3. The ring-shaped Plate 6 is perforated on its region projecting radially outwardly beyond the casing 5, in such a way that the annular space 4 is connected to a further annular space 9 surrounding the tubular part 7. This annulus 9 is about a Opening connected to a blow-out line 10.

Subsequently to the pipe part 7 is on the annular End wall 8 of the housing 2 is an elbow piece connected to the flue gas outlet of a boiler, not shown 11 arranged, which also serves to support a motor 12, which is connected to the vertical axis of the Housing 2 coaxially aligned motor shaft 12 is arranged. To protect the motor 12 from the effects of heat of the flue gases flowing through the elbow section 11 A bearing block 13 is used, on the flange-like plate 13 'of which the motor 12 is fastened, which is further away from the elbow section is. One attached to the elbow section 11

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Another flange-like plate 13 ″ of the bearing block 13 serves at the same time to hold a bearing part 14 a shaft part 15 which has a coupling piece. 16 is drivingly connected to the motor 12 is and by a provided for this purpose, sealed against the shaft part 15 (seals not shown) Opening in the elbow section 11 in continuation of the Motor shaft protrudes.

A disk arrangement 17 suspended thereon is connected to the shaft part 15 by means of its hollow shaft 18 non-rotatably connected. On the hollow shaft 18 there are several disks 19 forming the disk arrangement 17 (see FIG. 3). attached, which are designed as perforated plates and often cut radially inward from their outer edge are, so that radially flaps 20 are formed, which in the manner of propeller blades opposite the disc plane are twisted or entangled.

The discs 19 have decreasing diameter in the downward direction, so that the radial distance between the Outer edge of the respective disk 19 and the jacket 5 in the case of a disk 19 arranged further below is larger than in the case of a disk 19 arranged further up.

In the peripheral wall of the hollow shaft 18 are respectively in the immediate vicinity of the disks 1-9, in the example shown below the same, openings 21 arranged. The disks with a liquid supplied via the hollow shaft 18 can pass through these openings 21 be applied.

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The liquid provided for this purpose forms a liquid bath 22 on the lower base of the housing 2, into which the hollow shaft 18 with its open lower end between guide webs 23 immersed, which radially to the vertical Axis of the housing 2 are arranged and on the one hand stiffen the lower housing base and on the other hand a Prevent undesirably strong, circular circulating flow in the liquid bath 22.

To get liquid from the liquid bath to the openings and thus to be able to promote the disks 19 is in lower open end of the hollow shaft 19 a propeller-like Conveyor wheel arranged, which is also immersed in the liquid bath 22 and when rotating the hollow shaft 19 in the direction of rotation U detected liquid pushes up.

In order to prevent too much liquid from escaping from the openings 21 associated with the lower disks 19, said openings 21 of the lower disks have a correspondingly smaller overall cross-section.

The device described works in the following way:

If the disk arrangement 17 is driven to rotate in the direction of rotation U by means of the motor 12, then the Discs 19 twisted like a propeller blade due to their Flaps 20 as an axial fan, which the flue gases of the boiler connected to the elbow section 11 or the like. sucks in and drives through the treatment room 3. At the bottom, at a distance above the surface of the Liquid bath 22 ending edge of the jacket 5, the smoke gases when they hit the surface of the liquid

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bath 22 by 180 upwards into the annulus 4 diverted; from there the flue gases pass through the openings in the annular plate 6 into the the upper annular space 9, which they then leave via the blow-out line 10. To prevent the smoke gases reach the blow-out line 10 by the shortest route through the annular spaces 4 and 9, the breakthroughs can be arranged in the annular plate 6 only at a greater distance from the blow-out line 10.

In addition, a shielding plate can be arranged next to the confluence of the exhaust line in the annular space 9, which, for example, penetrates the annular space 9 in the radial direction j parallel to the vertical axis of the housing 2 and causes the flue gases in the annular space 9 to be essentially only in one direction of flow opposite to the Direction of rotation of the disk arrangement 17 to the blow-out line 10 can reach.

As the disk arrangement 17 rotates, its disks 19 are continuously filled with liquid via the openings 21; speed applied, which mainly at the edges of the in these disks 19 arranged holes and on the outer edge of the disks 19 to form one each Tears off annular spray zone. The downwardly decreasing diameter of the disks 19 is a undesirably strong obstruction of the flue gas throughput of the treatment room 3 avoided. This can be like explain as follows:

One running below the uppermost disk 19 horizontal (virtual) plane is essentially only penetrated by the liquid which is from the uppermost disc 19 is sprayed. A horizontal one running below the middle disk 19 The (virtual) level, on the other hand, is covered by a larger one

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Amount of liquid crossed, according to the spray performance of the two upper discs 19. One below the horizontal (virtual) plane running through the bottom slice 19 is ultimately defined by that of all three disks 19 interspersed with sprayed liquid. The one in the flow direction of the flue gases downwards increasing space between the edges of the discs and the jacket 5 prevents "clogging" of the the treatment room 3 penetrating flow path of the flue gases through the sprayed liquid.

Within the spray zones formed by the disks 19 the flue gases swirled by the disk arrangement 17 come into intimate contact with the sprayed liquid, so that practically all pollutants contained in the flue gases are absorbed by the liquid will. The flue gases are therefore scrubbed extremely intensively.

It is advantageous that special measures for dehumidifying the smoke gases entering the exhaust line 10 are superfluous are. Any liquid entrained in the flue gases in vapor form is for the most part condenses and thus excreted when the smoke gases impinge on the surface of the liquid bath 22 and diverted into the annular space 4. The remaining liquid condenses on the cooler outer wall of the Annular space 4, since this outer wall through the jacket 5 from the direct action of heat through the 3handlungsraum 3 entering smoke gases is protected and due to the constant cooling by the surrounding air at most can get lukewarm.

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To utilize the heat content of the treatment room 3 penetrating flue gases serves a heat exchanger 30 ring-shaped enclosing the disk arrangement 17, which is flowed through by a heat transfer medium. The heat exchanger 30 consists, for example, in itself known way from helical pipes.

The heat exchanger 30 is protected against the corrosive effects of the flue gases in that it is constantly exposed to the liquid sprayed from the disk assembly 17 and washed off accordingly; which sprayed Liquid is made from the smoke gases by suitable additives, which absorb the liquid neutralize the pollutants washed out, constantly kept in a sufficiently neutral range.

To neutralize the liquid, according to FIG. 1, a reaction vessel 31, which for example soda contains. Fresh water is constantly fed into this vessel via a feed line 32 and a valve 33 controlling the feed introduced, which then, mixed with soda, from the reaction vessel 31 via a line 34 into the liquid bath 22 flows. In addition, the liquid bath 22 is via the feed line 32 and another control valve Fresh water is supplied, so that on the one hand the small liquid losses are compensated for arise that the washed flue gas small proportions of the sprayed liquid in the exhaust line 10 carried off. On the other hand, the liquid bath 22 is controlled by the one controlled by the further control valve 35 Fresh water inflow is continuously partially renewed, since liquid from the liquid bath is constantly flowing through the overflow 46 is fed into the sewage network. This is due to the constant neutralization of the

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existing washing liquid harmless. Otherwise, the quantities involved are relatively small (in the order of magnitude of 1 liter / hour, if the flue gases of a boiler for a single or multi-family house are cleaned Need to become).

The liquid bath 22 is constantly communicating with an expansion tank 37 via a line 36, i.e. the levels in the liquid bath 22 and in the expansion tank 37 are the same. The expansion tank 37 is connected to the supply line 32 via a float-controlled valve 38 and is supplied with fresh water fed as soon as its level and, accordingly, the level of the liquid bath 22 fall below a setpoint value. This ensures that sufficient amounts of liquid are always present in the liquid bath 22 are.

In the exemplary embodiment according to FIG. 2, a is located inside the treatment room 3 in an upper area arranged channel-shaped collecting part 39, which receives a small portion of the sprayed liquid and passes through a line 40 into a settling basin 41. (It may be sufficient if instead of the collecting part 39 a correspondingly large opening connected to the line 40 is arranged in the jacket 5). On the bottom of the Settling basin 41, the sludge-like dirt that has passed into the settling basin 41 settles Liquid. The liquid essentially freed from the sludge-like constituents flows out of the settling basin 41 into the reaction vessel, from where the liquid with soda or the like. offset via line 34 in turn the liquid bath 22 is supplied. Otherwise, the embodiment shown in FIG. 2 agrees that of FIG. 1 is the same.

The embodiment of FIG. 3 differs from that of FIG. 2 in that from the deeper Sludge accumulation zone 41 'of the settling basin 41 a Line 42 leads to a sludge pump 43, which directs the sludge into an evaporator tray 44, which within the flue gas line between the spray device 1 and the combustion system, not shown is arranged. The hot flue gas in this area constantly removes the liquid contained in the sludge and leads it into treatment room 3. At the same time, the dried sludge, apart from very small residues, is under the heat of the flue gas converted to gaseous substances or burned, which then in the treatment room 3 are washed out.

If necessary, this can be done in the embodiments according to 2 and 3 separately arranged reaction vessel 31 are superfluous by the liquid in the settling tank 41 neutralizing agents (e.g. soda) are constantly added. In this case, the line 47 can directly to Run liquid bath 22. To add the neutralizing agent, for example soda, a little can be added to the Liquid of the settling basin 1 immersing container (not shown) be arranged on its of the underside of the liquid has an opening through which the liquid enters the neutralizing agent can absorb sufficient quantities.

In Fig. 3 there is a wind vane switch on the flue gas line connecting the combustion system to the spray device 1 45 arranged, which by means of its wind vane 45 'protruding into the flue gas flow is operated. The arrangement is such that the switch 45 is only actuated when the current is stronger

as it is present during operation of the spray device 1, the disk arrangement 17 of which acts as a fan. The wind vane switch 45 serves as a safety switch, which only in its actuated state the burner to switch on the combustion system. This ensures that the combustion system is only operated can be if the spray device 1 is also working.

Since the arrangement according to the invention allows practically the entire heat content of the flue gases to be used - the flue gases are cooled to almost room temperature, the device according to the invention can also be advantageously combined with open chimneys, which would otherwise lead very considerable amounts of heat to the outside via the flue gases. A combination of this type is also possible without major difficulties because the spray device works very quietly, in that the jacket 5 prevents the sprayed liquid from impinging directly on the walls of the housing. If necessary, the housing 2 can also be clad in a sound-absorbing manner.

Due to the extraordinarily high purity of the washed gases introduced into the blow-out line 10 5 chimneys made of particularly corrosion-resistant or acid-resistant Materials are superfluous.

The embodiment shown in Fig. 3 can optionally can be modified in such a way that the 0 sludge pump 43 is discharged via line 42 Propels sludge into a sludge filter, which is preferably a quick-change filter medium, e.g. in the form of a filter cartridge. This is where the solid constituents of the sludge are held back

Liquid passing through the filter can then in turn - for example next to the mouth of the line 40 - in the settling tank 41 are initiated.

In a modification of the embodiment shown in FIG. 1, the reaction vessel shown there can optionally 31 and the lines connected therewith (line and the line having the valve 33) are unnecessary will. Instead, something above the level of the liquid bath 22 on a housing 2 provided for this purpose Housing opening a basin-like shoulder 27 be arranged in the operation of the spray device 1 due to Wave movements on the surface of the liquid bath 22 reaches washing liquid. In paragraph 27 a Cup 28 or the like. used, which absorbs a neutralizing agent. This comes through small openings (not shown) near the bottom or in the bottom of the cup 28 in the sloshing into the shoulder 27 Washing liquid and thus - in accordance with the dimensioning of the openings in the cup 28 and in the arrangement of the paragraph 27 at a corresponding height above the level of the liquid bath 22 - in dosed quantities into the liquid bath 22.

In a departure from the representations in Figures 1 to, the heat exchanger 30 can also be designed as a double-walled, from Heat transfer medium flowed through hollow cylinder be formed. If necessary, it can be inside the hollow cylinder between its double walls a helical one be arranged approximately transversely to the walls of the double-walled cylinder extending guide surface, which causes that the heat transfer medium or the like the heat exchanger only on a helical path. can enforce.

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The wind vane switch 45 shown only in FIG. 3 can of course also be used with all the others in the Embodiments shown in the drawing or explained in the description may be arranged.

Claims (7)

Expectations 1.) Device for utilizing the heat of flue gases from firing systems, such as boilers, etc., with a heat exchanger exposed to the flue gases for heating a heat transfer medium flowing through the same, characterized in that the heat exchanger (30) in a treatment room (3) penetrated by the smoke gases. - serving as a flue gas scrubber - Spray device (1) with a arranged in the treatment room, the heat exchanger (30) completely with spray zone acting on the sprayed washing liquid is housed in which the pollutants carried along in the flue gases are absorbed by the sprayed liquid be, and that the sprayed liquid one the W COPY ROTERMUND MANITZ FINSTERWALD HEYN MORGAN Deutsche Bank AG 219 915 (BLZ 60070070) Seelbergstrasse 23 / 2S.7O00 Stuttgart 50 Robert-Koch-Str. 1,8000 Munich 2 ?. Lande.olrokass Stuttgart 2 09O 616 (BLZ 600 5O1 <3 Postschick: Stuttgait 40734-706 (BLZ 60010070) The storage container or reservoir (liquid bath 22) supplying the spray zone can be supplied to which a device assigned to the neutralization or monitoring of the acidity (31) of the collected washing liquid is. 2. Apparatus according to claim 1, characterized in that the heat exchanger (30) than ring-like in plan view Sheath at a radial distance encloses a disk arrangement (17) which is mounted rotating about a vertical axis is and their disks (19) with the washing liquid to be sprayed to form a on the disks adherent and on the edge and / or on recesses or recesses or the like. the discs (19) in the form of a annular spray zone tearing liquid coating can be acted upon. 3. Apparatus according to claim 2, characterized in that the heat exchanger (30) is arranged within a jacket (5) which surrounds it in a ring shape, which impinging sprayed washing liquid onto the heat exchanger (30) - at least partially - throws back. 4. Device according to one of claims 1 to 3, characterized in that the one connected to an overflow (46) Storage container or basin (liquid bath 22) constantly fresh washing liquid and / or from one The reaction vessel (31) can be supplied with washing liquid which is accommodated in the reaction vessel (31) Neutralizing agent (e.g. soda) has been added. mm <• tt «ft 5. Device according to one of claims 1 to 4, characterized in that a from the spray zone a small proportion of the sprayed liquid can be discharged into a settling basin (41), on the bottom of which accumulate sludge-like contamination of the liquid that in the settling basin (41) or a A neutralizing agent (e.g. soda) can be fed in to the same downstream reaction vessel (31), and that the liquid mixed with the neutralizing agent in the storage basin or the storage container (Liquid bath 22) is recyclable. 6. Apparatus according to claim 5, characterized in that in the sludge collection zone (41 ') of the settling basin (41) a line leading to a sludge pump (43) is arranged, which promotes the sludge in an evaporator tray (44), which is in a furnace with the spray device (1) connecting the flue gas line is arranged. 7. Device according to one of claims 1 to 6, characterized in that on the flue gas line connecting the spray device (1) to the furnace a wind vane switch (45) is arranged with a wind vane (45 ') protruding into the flue gas flow is which a burner of the combustion system is only switched on, sucking in the flue gases Switching on the spray device (1) is permitted.