EP1682821B1 - Method and device for controlling a chimney draught in an upstream connected exhaust gas cleaning system - Google Patents

Abstract

Process for reducing a chimney pulling action comprises immersing a lower open chimney tube (1) in a sink, forming a liquid barrier as an end of the chimney tube using a liquid (condensate) collected in the sink, and exposing a part of the chimney tube to release the pressure of the flue gas purification system by reducing the liquid meniscus below the edge of the chimney tube. An independent claim is also included for an arrangement for reducing a chimney pulling action. Preferred Features: The sink is lowered together with the liquid to lower the liquid meniscus. A groove (12) assigned to the lower end of the chimney is used as the sink. The liquid flows over an outer wall of the groove like a weir.

Description

The invention relates to a method and an arrangement for controlling the chimney draft of a chimney draft on an upstream emission control system.

Recently, it is permissible to operate exhaust gas purification systems without reheating the clean gas leaving the scrubber system and to use wet systems as chimneys. As a result, on the one hand, the total production costs and, on the other hand, the maintenance costs of the exhaust gas purification system can be markedly reduced. For inspection work and repairs in the components of the emission control system, especially in the scrubber, it must be ensured after switching off the boiler system that the chimney draft is largely interrupted in the system component to be cleaned or repaired. This is done in a conventional manner by suitable flaps or other closure elements, which are permanently or temporarily installed in the supply and / or discharge lines ( DE 34 01 922 A ). Permanently installed closure elements, such as flaps and the like, form additional line resistance and are themselves susceptible to interference and repair. Temporarily installed in the cable closure elements, such as inflatable balloons from the outside, can not absorb the occurring at large wire cross-sections differential pressures and loads sufficiently reliable and / or they require a relatively high installation costs.

The invention has for its object to provide a faster and easier dynamic seal / opening of the air passage cross-section available to regulate the pulling action of a chimney on an upstream emission control system.

This object is achieved by a method having the features of claim 1.

The arrangement for carrying out the method according to the invention is characterized by the features of claim 10.

A preferred embodiment of the arrangement for controlling the pulling action of a chimney on an upstream exhaust gas purification system is characterized in claim 14.

With the invention, a chimney or chimney draft can be reliably prevented by the components of the exhaust gas purification system during revisions and maintenance work and the condensate can be safely removed. The lowering of the liquid or condensate level is easy and quick to accomplish by removing the liquid from the pan, e.g. is discharged until the chimney is no longer immersed in the liquid. Through this process, the cross-section of the chimney pipe, possibly also a partial cross-section is exposed from below.

From the DE 23 46 515 B it is known per se to compensate for temperature-dependent changes in length of chimney pipes by Tauchkompensatoren. The lower end of a steel flue gas pipe has three concentric pipe sections, which are closed at the top and form narrow, but deep annular chambers. The middle tube section dives into a narrow, deep, filled with heavy oil ring cup. Means for lowering the tub together with the liquid level under the edge of the chimney pipe are not provided.

According to the invention, the bottom, open end of the chimney tube can be exposed so far by a correspondingly deep lowering of the tub, that the opening is easily accessible and, depending on the dimensions, even walkable. To resume operation of the emission control system, the tub only needs to be raised so far that a flue gas closure is ensured over the dipping into the liquid of the tub chimney. Depending on the distance of the liquid level to the lower edge of the chimney pipe, the flue gas termination can also be brought about by increasing the liquid level by supplying liquid up to the lower end of the chimney pipe.

In a preferred embodiment of the invention, a channel assigned to the lower end of the chimney and defining a drainage bottom on the outside is used as the tub. This has the advantage that only a small amount of liquid is needed to ensure a Rauchgasabschluss, since the wall of the flue gas tube is surrounded by a comparatively small volume of liquid. The drainage floor discharges impacted or precipitated condensate to the gutter.

The liquid barrier not only ensures the reliable flue gas seal, but also the continuous flow of the forming condensate. For this purpose, in a further development of the invention, the liquid is overflowed via a gutter outer wall in the manner of a weir.

The immersion depth of the chimney pipe in the channel can be adjusted and varied by vertical position positioning of the channel.

In a further development of the arrangement according to the invention it is provided that the bottom connected to the liquid channel is pyramid-shaped, conical or spherical cap-shaped and ensures a distributed over the circumference of the liquid flow into the liquid-conducting groove.

A particular advantage of both the method according to the invention and the associated arrangement is that the prerequisite for a completely open exhaust gas purification system is provided. The emission control system requires in Advantageously, no internals, such as flaps that contribute to the total cost of the system both in the creation and in the entertainment not inconsiderable. In this open system, a reliable interruption of the chimney draft during maintenance work is provided; because the chimney pipe is exposed so far that the flue draft can be carried out over the free opening between the tub or the raised and lowered floor assembly and the chimney pipe and the chimney draft at the emission control system can be dismantled. In the conventional arrangements, it is usually unnecessary to supply drafts outside the lower end of the chimney pipe. The drafts required for carrying out the method according to the invention, the drafts from below to be supplied to the chimney, the chimney shaft, for example, introduced in the conversions of the chimney pipe, suitable ventilation louvers and / or a roller shutter.

The chimney tube is freely accessible from below via its raised and lowered floor assembly. The drainage of the gutter is carried out automatically via the liquid barrier, the weir and at least one liquid drainage. The weir drains off only clear condensate, while solid particles can sediment on the gutter floor.

Advantageous and / or preferred developments of the invention will become apparent from the dependent claims.

• Fig. 1 eine schematische Darstellung des unteren Abschnitts einer Rauchgas- bzw. Schornsteinröhre mit Reingaskanalanschluss und einer Ablaufboden-Baugruppe, die in der dargestellten geschlossenen Position das offene untere Ende der Schornsteinröhre gegenüber der Umgebung luftdicht abschließt;
• Fig. 1A eine gegenüber Fig. 1 vergrößerte schematische Schnittansicht des in Fig. 1 mit "A" bezeichneten Teils einer längenveränderlichen Aufhängung, die die Ablaufboden-Baugruppe in der geschlossenen Position gemäß Fig. 1 hält;
• Fig. 1B eine schematische Schnittansicht des in Fig. 1 mit "B" bezeichneten Teils der Schornsteinröhre in der geschlossenen Position der Ablaufboden-Baugruppe im Bereich einer Flüssigkeitssperre mit Überlauf zu einem Kondensatablauf;
• Fig. 2 eine Draufsicht auf die in der geschlossenen Position befindliche Ablaufboden-Baugruppe;
• Fig. 2C eine vergrößerte Teilansicht entsprechend dem Ausschnitt "C" in Fig. 2 auf den Bereich des Kondensat-Überlaufwehrs;
• Fig. 3 eine schematische Darstellung des unteren Abschnitts der Schornsteinröhre in einer über Hebezeuge abgespannten offenen Position der Ablaufboden-Baugruppe, bei der die Schornsteinröhre nach unten freigelegt und der Kaminzug an der Abgasreinigungsanlage über die dabei entstehende freie Bodenöffnung abbaubar ist; und
• Fig. 4 ein abgewandeltes Ausführungsbeispiel der Schornsteinröhre mit eingezogenem unteren Öffnungsabschnitt und einer in der offenen Position ähnlich Fig. 3 befindlichen angepassten Ablaufboden-Baugruppe.

In the following we will explain the invention with reference to embodiments schematically illustrated in the drawings. In the drawing show:

• Fig. 1 a schematic representation of the lower portion of a flue gas or chimney pipe with clean gas duct connection and a discharge tray assembly which hermetically seals the open lower end of the chimney tube in the illustrated closed position with respect to the environment;
• Fig. 1A one opposite Fig. 1 enlarged schematic sectional view of the in Fig. 1 part of a variable-length suspension, designated by "A", corresponding to the discharge tray assembly in the closed position according to FIG Fig. 1 holds;
• Fig. 1B a schematic sectional view of the in Fig. 1 part of the chimney pipe marked "B" in the closed position of the drain tray assembly in the region of a liquid barrier with overflow to a condensate drain;
• Fig. 2 a plan view of the located in the closed position drain bottom assembly;
• Fig. 2C an enlarged partial view corresponding to the section "C" in Fig. 2 on the area of the condensate overflow weir;
• Fig. 3 a schematic representation of the lower portion of the chimney pipe in a hoisted over hoists open position of the drain floor assembly in which the chimney pipe exposed down and the chimney draft on the emission control system on the resulting free bottom opening is degradable; and
• Fig. 4 a modified embodiment of the chimney tube with retracted lower opening portion and a similar in the open position Fig. 3 located adapted drain tray assembly.

Fig. 1 schematically shows the lower portion of a chimney or exhaust pipe 1 with attached clean gas duct 2. The chimney pipe 1 is open at the lower end 3 ( Fig. 3 ) and will be in the in Fig. 1 shown closed position, ie in the operating state of connected via a clean gas duct 2, not shown in the drawing exhaust gas cleaning system of a drain-bottom assembly 10 gas-tight.

The drainage floor assembly 10 has a centered on the central axis 5 of the chimney pipe 1 pyramidal drainage floor 11 and a gas-tight connected to the latter circumferential groove 12. The assembly 10 is in the closed position according to Fig. 1 suspended by guying on the flue gas pipe 1. These braces are in the described embodiment ( Fig. 1A ) formed by tie rods 14. Chimney pipe side, the pull rod 14 is attached to an outwardly projecting bracket 6 and the bottom of a substructure 15 of the assembly 10. By adjusting associated drawbar nuts can adjust the vertical position of the assembly 10 with respect to the chimney tube 1, as will be explained in more detail below.

In the in Fig. 1 shown closed position of the drainage floor assembly 11 immersed the lower open end of the flue gas pipe 1 in the operating state with condensate filled groove 12 so far that a reliable liquid barrier is formed as a flue gas side conclusion of the chimney pipe 1 from the environment. The immersion depth is set via the tie rods 14 and can be, for example, 200-300 mm (corresponding to a pressure of ± 20/30 mbar.) At this immersion depth, a so-called blow through of flue gas in the case of pressure surges in the chimney can be sufficiently reliably excluded.

Fig. 1B shows one opposite Fig. 1 enlarged schematic section through the channel 12, which is filled with condensate to the height of an overflow weir 17. Runs during operation of the emission control system from the chimney pipe more condensate in the channel 12, so there is a constant transfer of liquid over the overflow weir 17 in a provided with a condensate drain overflow 18.

In Figure 2C is a plan view of the overflow weir 17 and the overflow 18 shown schematically. Overflow weirs are arranged in the described embodiment at three evenly distributed over the circumference. Tie rods and suspensions are arranged distributed over the circumference of the drainage floor assembly 10.

In the embodiment of the invention described above, three circumferentially distributed suspensions are provided via tie rods 14 and three overflow weirs 17. It is clear that the number of guying and overflow weirs depends on the design requirements and can be increased as desired. Instead of in Fig. 2 illustrated pyramid with octagonal base can also be provided other pyramids or rotationally symmetrical drainage floors.

In Fig. 3 is the drain tray assembly 10 in the open position to the open lower end 3 of the chimney pipe first shown. This open position corresponds to the revision state of the connected via the clean gas duct emission control system. In this open position, the drain floor assembly 10 is brought by means of hoists 16, which are each effective between a bracket 6 and the substructure 15. About these lifting the drain floor assembly 10 after completion of the revision of the emission control system back into the in Fig. 1 be shown raised closed position.

In the open position according to Fig. 3 the chimney pipe is completely uncovered. The chimney draft is routed over the exposed opening and the chimney flue connected to the flue gas cleaning system is dismantled so that the channel, which is open via the flue gas cleaning system, remains unaffected by the chimney draft.

The lowering and raising of the assembly 10 by means of the hoists 16 easily along the central axis 5 of the chimney 1. In the closed position, the tie rods 14 are anchored suitable for stationary determination of the drainage floor assembly, the desired depth of penetration 20 of the chimney pipe in the condensate of Gutter 12 can be adjusted exactly.

The execution according to FIG. 4 differs from the one according to Fig. 3 in that the lower open end 19 of the chimney pipe 1 'to be closed by the drainage floor assembly 10' is narrowed via a draw-in section 21, so that the chimney pipe is only partially cross-sectioned in the open position according to FIG Fig. 4 is exposed. The drain tray assembly 10 'can be correspondingly smaller and thus more cost-effectively constructed. Otherwise, the training corresponds to the arrangement according to Fig. 4 that of the arrangement according to Fig. 3 ,

Within the scope of the inventive concept, numerous modifications are possible. Some modifications with regard to the formation of the drainage floor 11 and the distribution of the overflow weirs 17 and the braces 14, 16 have already been mentioned above. The drainage of the channel 12 is usually exclusive via the overflow weirs and the condensate drain instead. Blockages due to solid particles are not to be feared as they sediment on the channel bottom. But it is also possible that in the bottom of the channel one or more processes are arranged, which can be opened if necessary. If necessary, the overflow weirs can be made height-adjustable in order to vary the immersion depth of the exhaust pipe within certain limits independently of the vertical position of the drainage floor assembly.

Claims (18)

1. Method of reducing chimney draught effect on an upstream waste gas cleaning system, characterised in that a downwardly opening chimney shaft (1; 1') is dipped into a trough in such a manner that with the help of a liquid collected in the trough a liquid lock is formed as closure, at the flue gas side, of the chimney shaft relative to the environment; and that for relief of the upstream waste gas cleaning system from the chimney draught effect (flue draw) at least a part of the cross-section of the chimney shaft is freed by lowering the liquid level below the edge of the chimney shaft.
2. Method according to claim 1, characterised in that the trough is lowered together with the liquid for lowering of the liquid level.
3. Method according to claim 2, characterised in that use is made as trough of a channel (12) associated with the lower end of the chimney and outwardly bounding a discharge base (11).
4. Method according to claim 3, characterised in that the liquid is allowed to overflow a channel outer wall in the manner of a weir (17).
5. Method according to claim 4, characterised in that overflow weirs (17) by way of which the channel liquid can overflow outwardly and the channel is emptied of water are associated with several different circumferential regions of the channel (12).
6. Method according to one of claims 3 to 5, characterised in that the immersion depth (20) of the chimney shaft (1) in the channel (12) is set by vertical positioning of the channel.
7. Method according to one of claims 3 to 6, characterised in that the channel (12) and the discharge base (11) are vertically adjusted to such an extent that the lower end (3) of the chimney shaft for reinstatement of the flue draw in the waste gas cleaning system that the chimney shaft dips by a predetermined depth (20) into the channel liquid.
8. Method according to claim 7, characterised in that the immersion depth (20) is set by variation of the vertical adjustment of the channel (12).
9. Method according to one of claims 3 to 8, characterised by use in an open waste gas cleaning system.
10. Arrangement for reducing the chimney draught effect of a flue draw on an upstream waste gas cleaning system, wherein a downwardly open chimney shaft (1; 1') can be dipped into a trough; and a liquid lock as closure, which is at the flue gas side, of the chimney shaft relative to the environment is formed by a liquid collected in the trough; characterised in that means (6, 14, 16) for vertical lowering of the trough together with the liquid relative to the chimney shaft are provided in order to free at least a part of the cross-section of the chimney shaft and to relieve the upstream waste gas cleaning system from the chimney draught effect.
11. Arrangement according to claim 10, characterised in that the trough is constructed as a channel (12) which is gas-tightly connected with an outwardly inclined discharge base (11) to form a subassembly (10).
12. Arrangement according to claim 1, characterised in that the discharge base (11) connected with the liquid-conducting channel (12) is of pyramidal, conical or spherical construction and ensures a discharge, which is distributed over the circumference, of the liquid into the liquid-conducting channel (12).
13. Arrangement according to claim 10, characterised in that a discharge base subassembly (10) consisting of discharge base (11) and channel (12) is mounted to be suspended at the chimney shaft (1; 1') by way of a suspension device (6, 14, 16) variable in length.
14. Arrangement according to claim 13, characterised in that the suspension device comprises several hoists (16) distributed over the channel circumference.
15. Arrangement according to claim 13 or 14, characterised in that the discharge base subassembly (10) is fastened to the chimney shaft (1) in such a manner by way of tie rods (14) adjustable in length that a closure at the flue gas side relative to the environment is guaranteed.
16. Arrangement according to one of claims 11 to 15, characterised in that overflow weirs (17) with standard weir height are arranged in several regions distributed over the channel circumference.
17. Arrangement according to claim 16, characterised in that liquid outflows (18) are connected downstream of the overflow weirs (17).
18. Arrangement according to one of claims 11 to 17, characterised in that openings, which are closable by ventilation louvres and/or roll-up doors, for the flue draw air are formed in the chimney shaft.

Images