EP2417393A1 - Pipe and guide element for installation in a pipe - Google Patents

Abstract

The invention relates to a pipe for conducting through or discharging wet gases, particularly for conducting through or discharging flue gases subjected to wet scrubbing. At the inside wall, the pipe has a helically shaped guide element. As a result of said design, the drop entrainment and/or the drop ejection of pipe is reduced. Furthermore, a guide element for installation in such a pipe is described. The pipe is preferably a wet chimney.

Description

 Pipe and guide element for installation in a pipe

The present invention relates to a pipe for the passage or discharge of wet gases, in particular for the implementation or discharge of a wet-scrubbing flue gases.

After wet scrubbers, for example wet scrubbers of flue gases, reheating devices in the form of heat exchangers or by direct introduction of energy by means of gas burners have been used to promote the wet gas through large chimneys up to 400 m high. In this way, the ejection of coarse drops from the chimney that fall to the ground in the immediate vicinity of the chimney should be prevented. However, these facilities are very expensive and maintenance-intensive or require a lot of energy.

Modern systems are therefore equipped with so-called wet fireplaces, which are about 250 m high. The gas is conveyed by means of booster blowers in front of or behind the wet scrubber. Due to the cooling of the moist gas on the way to the chimney outlet, there is a high amount of condensate inside the chimney and therefore to Expulsion of coarse drops from the chimney, which fall in the immediate vicinity of the chimney (plant, village) to the ground. So far, only a few cases built-in installations, such as axial cyclones, were installed in the large-scale fireplaces except simple drainage facilities, as they lead to very high energy losses due to the high speeds in the fireplace and also represent a satisfactory solution with regard to the drop removal.

Furthermore, so-called film traps or other baffles have been installed to reduce the drop ejection in many wet chimneys, which should prevent the entrainment of liquid films along the chimney wall. However, these measures are generally only of limited use, since the liquid film is entrained by the high gas velocities in such chimneys or drops are torn out of the film. A harmful drop ejection can therefore not be completely prevented even with these facilities.

From DE 298 15 970 Ul a chimney pipe with Innenprofi- lation for a wet chimney is known, and by the proposed internal profiling u. a. the condensation in the chimney pipe should be improved.

In WO 95/12784 a condensation chimney is described, wherein the wet, cold, condensing chimney has an outer chimney wall, in the interior of which an inner tube is arranged. To increase the contact surface with the flue gas, a profile tube is used as the inner tube. From WO 95/04246 a chimney is known, which is filled to increase the amount of condensate with a plurality of packing. The fillers used are hemispherical and realized as a grid construction.

The present invention has for its object to provide a tube in which a drop entrainment or drop ejection is prevented or reduced by particularly simple means with low energy loss.

This object is achieved in a tube of the type described above in that it has on its inner wall a helically shaped guide.

In the solution according to the invention, the gas flow is set in rotation by the arranged on the inner wall of the tube helical guide, that in the gas flow entrained droplets pass through the centrifugal acceleration of the rotating gas flow to the inner wall of the tube and can be discharged from there targeted and flow-calm , The guide element provided according to the invention therefore fulfills a dual function. On the one hand, it imparts a rotational movement or screw movement to the gas flow and, on the other hand, the guide element serves for catching and discharging the liquid drops collected on the tube inner wall. The above object is therefore achieved with particularly simple means. In addition, the proposed guide element has the advantage that the energy generated by its arrangement loss of the gas stream is low and in particular substantially lower than in conventional axial cyclones.

It is understood that the guide element provided according to the invention can extend over the entire length or only over part of the total length of the tube. The guide element runs helically or helically over the inner wall of the tube and is suitably attached to this or integrally formed therewith (by welding).

As far as the dimensioning of the guide element is concerned, this depends on the flow conditions prevailing in the tube. However, the following embodiments of the intended guide element are particularly preferred.

Preferably, the guide element has a width of 1/80 D to 1/5 D, where D is the inner diameter of the tube. Particularly preferably, a width of 1/20 D is used. The guide element therefore preferably extends in the interior of the tube maximally over a distance inwards, which accounts for 10% of the inner diameter of the tube. In this way too much energy loss of the gas flow is prevented.

As regards the pitch of the guide element, this is preferably in a range of 1/2 D - 10 D, wherein a pitch of 1/2 D is particularly preferably used. Since the guide element simultaneously serves to drain off the liquid drops collected on the tube inner wall, The pitch should be chosen so that proper liquid removal is ensured.

In a further preferred embodiment of the invention düng the inclination of the guide element from the pipe center to the inner wall of the tube is 0 ° - 60 °. A preferred inclination angle is 7 °. Although the guide element may also have an inclination of 0 °, a certain inclination from the center to the inner wall is preferred in order to form a kind of liquid channel through which the discharge of the liquid is possible without it dripping into the interior space between the guide element and thereby the risk of dripping is given.

Another preferred embodiment is characterized in that the inner edge of the guide element is folded over, preferably in the gas flow direction. As a result, a downstream turbulence of the flow is prevented behind the guide element. This arrangement also serves to reduce the pressure loss of the system, as well as to prevent re-entry of fluid into the main flow, and thus to Tropfenmitrisse vermei ^¬. The height of the fold is preferably 1/200 D - 1/40 D.

The guide element may be a plate-shaped planar element. However, there are also Ausführungsfor ^¬ men possible, which are structured in cross section. Thus, an embodiment is preferred in which the guide element is formed concave over its width, which favors the liquid ^¬ keitsabführung particularly. Convex configuration conditions are also possible. Preference is given to planar to concave embodiments.

The guide element expediently has at least one weir provided with a drainage channel. This weir serves to Flussigkeitsabfuhrung, wherein it jams the corresponding liquid, which is then discharged via a drain channel, which preferably extends through the wall of the tube to the outside. Expediently, weirs are installed with drainage channels distributed over the entire height of the tube and thus of the guide element, the drainage channels preferably being submerged via siphons. In this way, a discharge of the collected liquid takes place at different levels of the tube, so that it is avoided that collected liquid on flowing down again enters the main flow into the interior.

In accordance with the invention the formed pipe, the Rohrin ^¬ nenwand can also be formed by an element located in a Außengehause inner tube on which the guide element is detachably or non-detachably fixed. Inner tube and Leitele ^¬ ment can form a structural unit, which is used in an outer housing. Of course, such an inner tube also have several aufrechetzbare sections.

The inventively designed tube is used to carry out or for the discharge of gases. The inventively ge ^¬ measures concerned in this case serve to prevent Mitfuhrung of drops in the Gasstromung or a drop ejection or drop ejection when the tube abfuhrt the gas into the atmosphere. The seal provided with the guide element ne pipe can also be referred to as a kind of pre-separator (especially in closed pipe systems).

Preferably, the tube is designed as a wet chimney here is the task in the foreground to prevent drop ejection of Nasskamines.

In a further embodiment of the invention, the tube on its inner wall between adjacent Leitelement- sections on a film trap for the slid along the tube inner wall liquid film on. If, in fact, the gas flow has set in rotation, high tangential velocities can occur in the edge region, which then can drive the liquid film on the underside of the guide element helically upwards. This effect should be prevented by the intended film trap.

The film trap can for example be formed by an axially extending planar or curved web. The curved ridge is concave with respect to the direction in which the liquid film is displaced to serve as a catch. The film trap is preferably associated with one or more drainage pipes, so that the collected liquid can be removed from the pipe or from the pipe.

In a further embodiment of the invention, the film trap is formed by an axially extending drain pipe into which the guide element opens or which is crossed by the guide element. Here, the arranged on the inner wall of the pipe drain pipe with its outer contour forms a Film trap and serves at the same time for discharging the liquid film on its outer contour, which is at the points where the drain pipe is interrupted and bypasses the guide element, introduced into the drain pipe together with the liquid discharged from the guide element. Preferably, the drainage pipe bridges the region of the guide element by means of a pipe constriction, so that at this point both the liquid located in the drain pipe led down and the liquid running downwards on the outer contour of the pipe and the

Guide element discharged liquid can be introduced into the drain pipe. The pipe constriction embodied as an override element allows the liquid of the guide element to flow into the lower pipe section in addition to itself.

This embodiment of a film trap has the advantage that no additional drainpipe is required.

In yet another embodiment, the tube has a gas flow guide section below the baffle to promote the desired helical gas flow.

The tube formed according to the invention is preferably a vertically arranged tube. However, this does not exclude that the tube can also be designed as horizontally or obliquely arranged tube. In any case, the invention is generally suitable for any type of pipeline that serves to carry or remove wet gases. The guide element may be releasably secured to the pipe inner wall, for example by screwing, but also be integrally connected thereto, for example by welding or laminating. Suitable materials are plastics, in particular GfK, PP, as well as metals.

In a further embodiment of the invention, the width of the guide element tapers over the length of the tube. If the guide element is designed, for example, as a channel, the channel width can be reduced in this case. In this embodiment, the width of the guide element is adapted to the size of the volume flow of the liquid to be discharged, which is naturally greater in the initial region of the tube than in the end region thereof. The taper of the guide element can be carried out continuously or stepwise.

In yet another embodiment of the invention, the guide element has a varying pitch. The pitch can be adapted individually to the particular circumstances, for example, be designed to be smaller in the initial region of the tube than in the end.

In yet another embodiment, the tube has two or more vanes. In this embodiment, for example, two or more vanes may be spaced apart and parallel to one another. For example, in the case of two guide elements, these can start off offset by half the circumference of the tube and extend parallel to one another or upwind in the case of vertically arranged tubes. In this way, the targeted rotational effect can be increased and it can be saved in relation to the pipe or the wet chimney length or height.

The present invention further relates to a guide element for installation in a pipe with the features described above. Such a guide element can preferably form a structural unit together with a pipe, in particular an inner pipe.

The invention will be explained below with reference to an embodiment in conjunction with the drawings in detail. Show it:

Figure 1 is a schematic longitudinal section through part of a wet fireplace;

Figure 2 is a perspective view of a portion of the wet ^¬ fireplace of Figure 1 on an enlarged scale;

FIG. 3 shows a longitudinal section through a part of the wet chimney shown in FIGS. 1 and 2, again enlarged;

Figure 4 is a detail view of the wet fireplace in vertical section;

Figure 5 is a detail view of the wet fireplace in the horizontal section;

FIG. 6 shows a detailed view of another embodiment. form of a wet fireplace;

Figure 7 is an enlarged view of a detail of Figure 6; and

FIG. 8 shows a top view of the article of FIG. 7.

FIG. 1 shows a schematic partial longitudinal section through a wet chimney 1. The inner wall 3 of the wet chimney is provided with a helical guide element 2 which extends over the length of the wet chimney. The inner wall 3 may be, for example, the inner wall of the fireplace housing or the inner wall of a chimney pipe, which is inserted into a Kamingehäuse.

The wet chimney 1 is connected downstream of a wet scrubber of flue gases and serves to discharge the flue gases into the atmosphere. The gas flow is directed in Figure 1 from bottom to top. By means of the guide element 2 arranged on the inner wall 3 of the wet chimney 1, the gas flow is imparted with a rotational movement or helical movement, so that the liquid drops entrained in the gas reach the inner wall 3 of the chimney by centrifugal acceleration and there via the provided helical or spiral guide element 2 be discharged down. At certain intervals discharge ducts are arranged at the wet chimney, which extend through the chimney wall to the outside, to lead out of the guide element 2 downwardly discharged liquid from the chimney and thus to prevent the liquid from getting back into the main flow. at the discharge channel can also be a pipe inside the chimney.

The helical or spiral guide element 2 therefore characterizes on the one hand the gas flow a rotation or

Screw movement and on the other hand serves to dissipate the accumulated in the region of the chimney inner wall 3 liquid. For this purpose, the guide element is concave in the form of a groove, as shown in particular in Figure 2. As already mentioned, discharge channels are provided at intervals over the length of the wet chimney, which are in contact with the guide element 2, in order to feed out the downwardly discharged liquid from the comb. Corresponding weirs may be arranged in front of these discharge channels in order to stow the discharged liquid. These weirs are not shown in the figures.

Figure 3 shows an enlarged section of the formation of the guide element 2 in the form of a concave groove.

The width of the guide element 2 is dimensioned so that the guide element of the gas flow can impart a sufficiently large rotational or screw movement and, furthermore, can perform its function as Flussigkeitsabfuhrelement. Too large a width is not desirable so as not to cause excessive energy drop of the gas flow. Preferred width ranges are given above in the description. Corresponding considerations apply to the pitch of the guide element 2. These should also be optimized so that the guide element described above both Can fulfill tasks. Preferred ranges are also given above.

It is essential that the interior of the wet fireplace is kept free of internals in order not to cause excessive energy loss in relation to the gas flow. Furthermore, to be prevented by the guide element that in the area of the fireplace inner wall accumulated liquid gets back into the main flow in the interior and is entrained there by the gas flow. The appropriate dimensioning of the guide element is to be optimized according to the flow conditions prevailing in the wet chimney.

FIG. 4 shows a detailed view of the wet fireplace 1 in the vertical section. It can be seen the guide element 2, which is formed in the shape of a groove and having a corresponding weir 6 with exnem drain pipe 4, which is guided through the chimney inner wall to the outside. Further, located on the chimney inner wall 3, a film trap 5, which is formed as a web between the individual Leitelementabschnitten extending vertically on the inner wall 3 (also shown in Figure 1). The film trap 5 prevents the liquid film forming on the inner wall from being displaced upwards by the rotational flow. The film enters the bag-shaped film trap and runs from there down into the channel-shaped guide element 2, from which it is discharged via the drainage pipe 4. In the horizontal section of FIG. 5, the flow direction of the liquid on the guide element is indicated by the upper arrow, and the upward movement of the gas flow by the lower arrow. Further FIG. 5 shows a weir 6 arranged on the guide element 2.

FIG. 6 shows a view of a further embodiment of a film trap, which in this case is in the form of a drain pipe 10 which is arranged on the inner wall of the wet fireplace. The drain pipe 10 is divided one above the other into a plurality of drain pipe sections, which are connected by means of bridging elements (pipe constrictions) 11 at the points where they cross the guide element 2. Figure 7 shows an enlarged view of such a crossing point with the guide element 2. The connection between the two sections of the drain pipe 10 is formed by a pipe constriction 11 (bridging element), which narrows towards the lower drain pipe section and laterally exposes part of the opening of the lower drain pipe section so that the liquid flowing downwards on the outer contour of the drainage pipe and the liquid discharged from the guide element 2 can flow into the lower drainage pipe section.

FIG. 8 shows a schematic plan view of the embodiment of FIG. 7.

Claims

cLAIMS 1. Pipe for the passage or discharge of wet gases, in particular for the implementation or discharge of a wet-scrubbing flue gases, characterized in that it comprises on its inner wall (3) has a helically shaped guide element (2). 2. Pipe according to claim 1, characterized in that the guide element (2) has a width of 1/80 D - 1/5 D, where D is the inner diameter of the tube (1). 3. Pipe according to claim 1 or 2, characterized in that the pitch (pitch) of the guide element (2) is 1/2 D - 10 D (D = inner diameter of the tube). 4. Pipe according to one of the preceding claims, characterized in that the inclination of the guide element (2) from the center to the inner wall (3) of the tube (1) is 0 ° - 60 °. 5. Pipe according to one of the preceding claims, characterized in that the inner edge of the guide element (2) is folded over in the gas flow direction. 6. Pipe according to one of the preceding claims, characterized in that the guide element (2) is concave over its width. 7. Pipe according to one of the preceding claims, characterized in that the guide element (2) is formed as a groove. 8. Pipe according to one of the preceding claims, characterized in that the guide element (2) has at least one provided with a drain channel weir. 9. Pipe according to one of the preceding claims, characterized in that the pipe inner wall (3) is formed by an inner tube arranged in an outer tube. 10. Pipe according to one of the preceding claims, characterized in that it is designed as a wet chimney (1). 11. Pipe according to one of the preceding claims, characterized in that it has on its inner wall (3) between adjacent Leitelementabschnitten a Filmfal- Ie (5). 12. Pipe according to claim 11, characterized in that the film trap (5) is formed by an axially extending planar or curved web. 13. Pipe according to claim 11 or 12, characterized in that the film trap (5) is associated with a drain pipe (4). 14. Pipe according to claim 11, characterized in that the film trap (5) by an axially extending drain pipe (10) is formed, in which the guide element (2) opens. 15. Pipe according to claim 14, characterized in that the drain pipe (10) the region of the guide element (2) with Help of a pipe constriction (11) bridged. 16. Pipe according to one of the preceding claims, characterized in that it has a gas flow guide section under the guide element. 17. Pipe according to one of the preceding claims, characterized in that the width of the guide element (2) tapers over the length of the tube. 18. Pipe according to one of the preceding claims, characterized in that the guide element (2) has a varying pitch. 19. Pipe according to one of the preceding claims, characterized in that it has two or more guide elements. 20. guide element (2) for installation in a pipe according to one of the preceding claims. 21 guide element (2) according to claim 20, characterized in that it forms a structural unit together with a pipe, in particular inner tube.