阅读说明：本技术 具有冷凝物收集器的湿烟囱导向叶片 (Wet stack guide vane with condensate collector ) 是由 艾伯特·德·克雷伊 巴斯蒂安·范德·沃德 于 2018-01-10 设计创作，主要内容包括：一种用于使湿烟囱(10)中的烟道气偏转的导向叶片(28),包括前导向面(40)和相对的后导向面(42)以及用于从烟道气中去除液滴的冷凝物收集器(30)。冷凝物收集器(30)包括外壳(59),该外壳具有在导向叶片(28)的前导向面(40)中用于烟道气进入的入口(54)和用于烟道气离开的出口(68)。外壳(59)限定了从入口(54)到出口(58)的烟道气的流动路径,液滴将在这里从烟道气中去除。冷凝物收集器(30)还设置有用于收集从烟道气中分离的液滴的沟槽(62)。(A guide vane (28) for deflecting flue gas in a wet stack (10) includes a front guide surface (40) and an opposing rear guide surface (42) and a condensate collector (30) for removing liquid droplets from the flue gas. The condensate collector (30) comprises an outer casing (59) having an inlet (54) for flue gas entry and an outlet (68) for flue gas exit in the front guide face (40) of the guide vanes (28). The housing (59) defines a flow path for the flue gas from the inlet (54) to the outlet (58) where liquid droplets are to be removed from the flue gas. The condensate collector (30) is further provided with a gutter (62) for collecting liquid droplets separated from the flue gas.)

1. Guide vane (28) for deflecting flue gas in a wet stack (10), comprising a front guide surface (40) and an opposite rear guide surface (42) and a condensate collector (30) for removing liquid droplets from the flue gas, wherein the condensate collector (30) comprises:

-a housing (59) having an inlet (54) for flue gas entry and an outlet (68) for flue gas exit in a front guide face (40) of the guide vane (28), and

wherein the housing (59) defines a flow path for flue gas from the inlet (54) to the outlet (58), an

-a gutter (62) for collecting liquid droplets separated from the flue gas.

2. The turning vane of claim 1, wherein the flow path for flue gas comprises a non-linear flow path.

3. The guide vane of claim 1, wherein the inlet (54) is defined by an upper edge (52) of the first portion (46) of the front guide face (40) and a lower edge (50) of the second portion (48) of the front guide face (40).

4. The guide vane according to claim 3, wherein a lower edge (50) of the second portion (48) is offset relative to an upper edge (52) of the first portion (46) to define a gap upstanding from the front guide surface (40).

5. The guide vane according to claim 4, wherein an upper edge (52) of the first portion (46) of the front guide surface (40) and a lower edge (50) of the second portion (48) are overlappingly spaced apart from each other.

6. Guide vane according to any one of the preceding claims, wherein the casing (59) comprises a drop forming element (56) having a lower portion (60) extending downwardly beyond an upper edge (52) of the first portion (46) at a first distance from a back of the first portion (46).

7. Guide vane according to any of the preceding claims, in particular according to claim 6, wherein the groove (62) comprises a groove plate (64), the lower part of which is attached to the back (66) of the first part (46), thereby forming a groove.

8. Guide vane according to claim 7, wherein the upper part (67) of the fluted plate (64) extends upwardly beyond the lower end (60) of the drop forming element (56) at a second distance from the back of the second portion (48), wherein the second distance is greater than the first distance.

9. Guide vane according to any of the preceding claims, wherein the bottom of the fluted plate (64) slopes downwardly towards the sides of the guide vane (28).

10. The guide vane of claim 9, wherein the bottom portion slopes downwardly from a middle portion of the guide vane toward both side surfaces.

11. Guide vane according to any of the preceding claims, wherein the rear guide surface (42) comprises a rear plate (72), the lower end (74) of which is attached to the lower end of the first part (46) and the upper end (76) of which is attached to the upper end of the second part (48) such that the guide vane (28) has an airfoil shape, and wherein the outlet (68) of the outer shell extends through the rear guide surface (42).

12. Guide vane according to any one of claims 1-10, wherein the rear guide surface (42) comprises a rear plate (72), a lower end (74) of which is attached to a lower end of the first part (46) and an upper end (76) of which extends at a distance from an upper end of the second part (48), wherein the spaced upper end defines the outlet (68) of the housing (59).

13. Guide vane according to any one of the preceding claims, wherein the front guide surface (40) has a curvature (100) from its lower end towards its upper end.

14. Guide vane according to any one of the preceding claims, wherein the front guide surface (42) is provided with an additional condensate collector (80) at a position below the first condensate collector (30).

15. Guide vane according to claim 14, wherein the additional condensate collector (80) comprises a recess (82) in the front guide surface (40) and a T-profile (84), the leg (86) of which extends into the recess (82) and terminates at a distance therefrom.

16. Wet chimney (10), in particular for a power plant, for emission of flue gases into the atmosphere, comprising a housing (12) defining a vertical duct (14) having an inlet (16) and an outlet (24) at an upper end (26) thereof, the vertical duct being provided with one or more guide blades (28) according to any one of the preceding claims.

17. Wet chimney according to claim 16, wherein a plurality of guide vanes (28) are arranged with their lower ends equally spaced from each other.

18. Wet chimney according to claim 16 or 17, wherein the upper end is arranged such that the flow areas defined by the guide vanes (28) and the housing inner wall (36) are equal.

Technical Field

The invention relates to a guide vane for deflecting flue gas in a wet stack with a condensate collector, and to a wet stack with one or more such guide vanes.

Background

Today, new coal-fired utility power plants are often provided with flue gas desulfurization systems, and older plants are upgraded. Many of these systems employ wet techniques. It is known in the art that in such cases, the moist (fully wet-through) flue gas exiting the desulfurization system can be reheated to dry the flue gas before the gas is passed to the stack. However, due to the rising energy costs and the demand for reduced SO2 emissions, flue gas reheating is no longer an economical and environmentally friendly option. Instead, so-called wet stack operation is put into practice. That is, the flue gas exiting the wet desulfurization system enters the stack directly. Typically, a demister device for capturing liquid droplets from the flue gas is interposed between the wet desulfurization system and the stack. The water vapour condensed on the inner walls of the ducts between the desulfurization system and/or the demisting device and the chimney, and on the inner walls of the chimney itself, forms a liquid film on these walls together with the droplets carried from the demisting device. The liquid film is collected and discharged from the chimney. Given that droplets from the liquid film may be re-entrained by the flue gas stream, if the design of the duct, stack and condensate collector does not work properly under actual operating conditions, an unacceptable amount of droplets may be expelled from the top of the stack and deposited near the stack. This phenomenon is also referred to as "spitting".

It is also known in the art to provide one or more guide vanes for guiding the deflection of the flue gas flow, in particular at the flue gas inlet in the stack.

For example US6562108B2 discloses a chimney having a liquid separator for removing liquid entrained in a gas in the chimney, the chimney having a bottom and a top and comprising at least one duct having a longitudinal axis entering the chimney near said bottom. At least one vertical vane is disposed at and at an angle to the longitudinal axis of the pipe. A liquid collector is disposed near the top of the chimney for recovering liquid.

Furthermore, CN104474794B discloses a condensate collection device at the top end of a wet stack flue gas deflector. The condensate collection device includes a fixed bracket and a collection trough mounted on top of a wet stack flue gas deflector by the fixed bracket. Both sides of the collecting groove are provided with a notch. The lowest position of each notch is provided with a drain hole and a drain pipe. And a reinforcing plate and a water guide plate are arranged in the collecting tank. The water deflector is used to direct the collected condensate to flow to a drain for discharge from the chimney. According to CN104474794A, condensate is effectively prevented from being re-entrained. In the disclosed embodiment, the condensate film is believed to flow up the surface of the deflector to its top end due to the flow of flue gas, and overflow the top end into the collection trough. A disadvantage is that during travel along the surface of the guide plate, especially at the overflow moment, the risk of re-entrainment of droplets from the membrane into the flowing flue gas may occur, reducing the droplet removal efficiency, and there is still a risk of splashing.

From CN203857475U a guide vane device with a lower condensate collector for the wet chimney inlet is known. In particular, the guide vane device comprises guide vanes and struts. The guide vane is arranged at the bottom of the inlet of the chimney. One end of each strut is fixed on the dust deposition platform, and the other end of each strut is connected with the corresponding guide blade. The guide vanes form an included angle with the horizontal part of the chimney. The upper surfaces of the guide vanes face a flue gas inlet arranged in the bottom of the stack so that, after the flue gas has entered, condensate produced in the flue gas in the stack is collected by an ash hopper and discharged from the stack. Furthermore, re-entrainment of liquid droplets from the condensate film on the guide vanes may occur, since the liquid has to flow down on the surface of the guide vanes to the ash deposit in the opposite direction to the flue gas flow.

Disclosure of Invention

The present invention aims to provide a guide vane with an improved condensate removal function, or a suitable alternative.

In a first aspect, the present invention provides a guide vane for deflecting flue gas in a wet stack, comprising a front guide surface and an opposite rear guide surface and a condensate collector for removing liquid droplets from the flue gas, wherein the condensate collector comprises:

-a casing having an inlet for flue gas into the front guide face of the guide vane, wherein

The housing defines a flow path for the flue gas from the inlet to the outlet, an

-a gutter for collecting liquid droplets separated from the flue gas.

The guide vane for deflecting flue gas in a wet stack according to the invention comprises a front guide surface and an opposite rear guide surface. The front guide surface faces the inlet of a chimney, which generally comprises a casing defining upright ducts for the flow of flue gases, optionally provided with a lining such as a closed cell glass block, for example made of borosilicate. The chimney has: one or more inlets for introducing flue gas, typically at the lower part of the stack; and a top outlet for discharging flue gas into the environment. The guide vanes are provided with condensate collectors for removing liquid droplets collected from the flue gas on the front guide surfaces of the guide vanes. According to the invention, the condensate collector comprises a housing. Some of the walls defining the outer shell, in particular the side walls, may be provided by a housing defining a duct in which the guide vanes are mounted. An inlet for flue gas entry is provided on the leading guide face of the guide vane. Typically, the inlet extends over the entire width of the guide vane up to the inner wall of the housing defining the duct of the chimney. The condensate collector also has an outlet for the flue gas to exit and re-enter the duct to allow the flue gas to flow further in the duct to the top outlet of the stack. The outlet also extends as far as the inner wall of the housing, typically over the entire width of the guide vane. In the housing, a flow path for flue gas from an inlet at the front guide face to an outlet is provided, wherein liquid droplets are separated from the flue gas flowing through the housing. The droplets hit the inner wall of the housing and are collected thereby. Examples of flow paths which are capable of separating liquid droplets from flue gas are non-linear flow paths of flue gas, in particular flow paths having one, two or more U-turns. The gutter, which is usually arranged in the lowermost part of the housing, collects the liquid droplets separated from the flue gas. Typically, the gutter has one or more connecting members connected to a drain pipe in order to drain collected droplets from the chimney as condensate.

During operation, the condensate film will flow along the front guide surface to the inlet and overflow from the inlet into the condensate collector, where the condensate will enter and drain from the trough. Furthermore, since the guide vanes split the flue gas flow into a forward flow flowing along the front guide faces of the guide vanes and a counter flow flowing behind the guide vanes, the pressure of the forward flow of flue gas will be higher than the pressure of the counter flow. Due to this pressure difference, a portion of the forward flow is forced into the inlet of the condensate collector. Due to the weight of the droplets, the droplets cannot follow the path within the inlet and the housing through which the flue gas travels, whether they are still contained in part of the front flow or re-entrained. Thus, the droplets will hit the inner wall of the housing, resulting in additional deposition and collection. The condensate thus collected will drip from the wall into the gutter where it is further collected and drained along with a film of condensate overflowing the top edge of the first portion. In this way, the removal efficiency is improved and the risk of undesired splashing is reduced.

In a preferred embodiment, the inlet of the housing is defined by an upper edge of the first portion of the front facing surface and a lower edge of the second portion of the front facing surface.

In an advantageous embodiment, the lower edge of the second portion is offset with respect to the upper edge of the first portion, thereby defining a gap upstanding from the front surface. The offset lower edge of the second portion prevents droplets from the liquid film on the first portion from being carried through the inlet of the condensate collector to the second portion and ensures that the liquid film flows into the inlet of the condensate collector over the upper edge of the first portion of the front guide surface. Preferably, the upper edge of the first portion and the lower edge of the second portion of the guide plate are spaced overlapping each other, thereby further reducing the risk of liquid droplets from the film being carried from the first portion to the second portion of the leading guide surface of the guide vane.

The housing of the condensate collector has a flue gas flow path from the inlet to the outlet where liquid droplets are removed from the flue gas. The flow direction of the portion of the flue gas stream entering the condensate collector is deflected relative to the main flow direction of the flue gas along the front guide surface. This deflection already occurs at the entrance in the front guide surface and can be further supported by the design of the housing. An example of such a flow path that supports additional removal of liquid droplets from the flue gas within the enclosure is a non-linear flow path. In such a non-linear flow path within the housing, the inlet and outlet cannot be connected by a straight line. Examples of such non-linear flow paths include undulating or saw-tooth paths. In an advantageous embodiment, the non-linear flow path comprises at least one U-turn, preferably two or more.

In a preferred embodiment, the housing of the condensate collector comprises a droplet forming element, such as a plate, the lower part of which extends downwards beyond the upper edge of the first part at a first distance from the back of the first part. The upper portion may be directly connected to the back of the second portion. This structure forms a first U-turn around the upper edge of the first portion, ensuring that droplets in the flue gas hit the droplet-forming elements, are deposited on and flow to the lower part of the droplet-forming elements, and drop into the underlying trench.

In another preferred embodiment of the invention the trough comprises a trough plate, the lower part of which is attached to the back of the first part, thereby forming a trough for collecting condensate. The upper portion of the recess preferably extends upwardly beyond the lower end of the drop forming element at a second distance from the back of the second portion, wherein the second distance is greater than the first distance. In this way, a second U-turn in the flow path around the lower part of the drop forming element is formed, as well as said groove between the back of the first part and the fluted plate. Condensate will be collected in the grooves and drained therefrom. Furthermore, the spaced apart droplet forming elements and the fluted plate form an outlet of the condensate collector housing such that a portion of the flue gas flow flowing through the housing exits the outlet into the stack duct in a flow direction substantially the same as the main flow direction of the flue gas. Thus, any negative effects of the partial flow on the main flow, such as turbulence, are small.

To enhance drainage of the trough, the bottom of the fluted plate slopes downwardly toward the sides of the fluted plate, preferably from the middle towards both sides of the fluted plate.

In another embodiment, the rear guide surface of the guide vane according to the invention comprises a back plate, the lower end of which is attached to the lower end of the first part and the upper end of which is attached to the upper end of the second part, such that the guide vane has an airfoil shape, and wherein the outlet of the condensate collector extends through the rear guide surface. In this embodiment, the airfoil-shaped profile of the guide vanes increases the pressure difference between the inlet at the front guide surface and the outlet in the rear guide surface of the guide vanes, thereby increasing the partial airflow through the condensate collector and thus also increasing the removal efficiency.

In another embodiment, such a rear plate is attached at its lower end to the lower end of the front guide surface and extends at its upper end spaced from the upper end of the front guide surface, wherein the spaced upper end defines the outlet of the housing of the condensate collector. In this embodiment the flow direction of the part of the gas flow leaving the outlet is substantially parallel to the flow direction of the main flow of flue gas, thereby reducing disturbances to the main flow.

The front guide surface preferably has a curvature from its lower end in the direction of its upper end, typically a 90 ° arc. The upper end preferably has a straight portion which, once installed, extends parallel to the longitudinal direction of the pipe. The straight portion reduces the turbulence of the flue gas in the duct towards the stack outlet. The inlet of the condensate collector is preferably located at or near the transition of the curved portion (first portion) to the straight portion (second portion).

The back plates, if present, usually have straight ends, between which there is a curved portion, usually also a 90 ° arc, however with a smaller radius than the arc portion of the guide plates.

In another embodiment the front guide surface, in particular the first portion thereof, is provided with an additional condensate collector at a position below said first condensate collector. For example, the additional condensate collector may be configured as outlined above for the first condensate collector.

In a preferred embodiment, the additional condensate collector comprises a recess in the front surface of the front guide surface and a T-profile, the legs of which extend into the recess and terminate at a distance from the recess. Advantageously, the recess forming the groove is inclined from both side faces towards the middle of the connection provided to the drain pipe.

In a second aspect, the present invention relates to a wet chimney, in particular for a power plant, such as a coal fired power plant, for discharging flue gases into the atmosphere, the chimney comprising a housing defining a vertical duct having an inlet and an outlet at its upper end, the chimney being provided with one or more guide vanes according to the invention, in particular at a position within the duct opposite the inlet.

In an embodiment of the invention, the plurality of guide vanes are arranged with the lower ends equally spaced from each other. Preferably, the upper ends are arranged such that the flow areas defined by the guide vanes and the housing wall are equal. Both features contribute to the advantageous splitting of the flue gas stream into a plurality of partial streams, deflecting the flue gas stream and droplet separation, and merging the partial streams outside the guide vanes.

Typically, the height of the industrial wet chimney according to the invention is between 50 and 400 meters, preferably from 100 to 175 meters. Although the general shape of the cross-section (flow area) of the pipe, e.g. square, rectangular, oval, is not critical, the flow area is typically circular and ranges from 3 to 15 meters in diameter.

Drawings

The invention is illustrated below by the accompanying drawings, in which:

fig. 1 shows an embodiment of a wet stack provided with guide vanes according to the invention;

FIG. 2 is a first embodiment of a guide vane according to the present invention;

FIG. 3 shows a second embodiment of a guide vane according to the invention;

fig. 4a) and 4b) show a third embodiment of a guide vane according to the invention; and

fig. 5 is another embodiment of a wet stack provided with a plurality of guide vanes according to the present invention.

Detailed Description

In fig. 1, an embodiment of a wet stack 10 is schematically illustrated. The vertical wet stack 10 includes a housing 12, which may be provided with an inner lining (not shown). The housing 12 defines an upright duct 14 for flue gas. An inlet 16 for introducing flue gas from a plant 18, such as a (coal-fired) power plant provided with a wet desulfurization system 20, is located in the lower portion 22 of the duct 14. An outlet 24 at the upper end 26 of the duct 14 discharges the flue gas to the atmosphere. At the inlet 16, a guide vane 28 is provided, which has a condensate collector, which is designated as a whole by reference numeral 30. The guide vanes 28 divert flue gas entering through the inlet 16 and deflect the flue gas through the duct 14 towards the outlet 24. A false floor 32 is provided in the duct 14, generally below the inlet 16. The rear deflector plate 34 may be positioned at an inner wall 36 of the housing 12 opposite the inlet 16.

Various embodiments of the turning vanes 28 are shown in more detail in fig. 2-5.

Fig. 2 shows an embodiment of a guide vane 28 according to the invention in a sectional view. Guide vane 28 has a forward guide surface 40 and an aft guide surface 42. The front guide surface 40 comprises a curved (concave) first portion 46 and a (straight) second portion 48, for example made of stainless steel sheet material. The lower end 50 of the second section 48 is offset and spaced from the upper end 52 of the first section 46, thereby forming an inlet 54 of the condensate collector 30 for a partial gas flow of flue gas. The gap-shaped inlet 54 extends over the entire width of the duct 14 up to the inner wall 36 of the housing 12. As shown, the upper end 52 of the first portion 46 extends beyond the lower end 50 of the second portion 48, thereby preventing droplets of the condensate film from migrating from the first portion 46, bypassing the inlet 54, toward the second portion 48. A drop forming element 56, in this embodiment a plate, is mounted on a back 58 of the second part 48 and extends with its free lower end 60 downwardly behind the upper end 52 of the first part 46 at a distance from the upper end 52. Droplets contained in a portion of the gas stream will impact drop forming element 56 and deposit on the drop forming element, flow toward lower end 60, and fall into channel 62. The channel 62 is formed by a channel plate 64 mounted to a back 66 of the first portion 46. In the illustrated embodiment, the fluted plate 64 is shaped such that its upper end 67 extends upwardly parallel to the second portion 48 at a second distance from the second portion 48. The gap between the back 58 of the second section and the upper end 66 of the fluted plate 64 is an outlet 68 of the condensate collector 30 for a portion of the gas flow in the flue gas that flows through the condensate collector 30 during operation. The upper end 52 of the first portion 46, the lower end 50 of the second portion 48, the droplet forming elements 56, the fluted plate 64 and the corresponding portion of the inner wall 36 of the housing 12 together define an outer shell 59 of the condensate collector 30. A partial gas flow of the flue gas flows from the inlet 54 through the housing 59, via a flow path comprising two U-turns, to the outlet 68, where the partial gas flow leaves the condensate collector 30 in a direction parallel to the main flow direction of the flue gas.

Fig. 3 shows a further exemplary embodiment of a stator blade 28, the stator blade 28 having a similar construction to the stator blade of fig. 2. Similar to the embodiment of fig. 2, parts of the embodiment of the guide vane 28 are denoted by the same reference numerals. In the embodiment of the figures, the fluted plate 64 does not have a straight upstanding upper end. Instead, a cover plate 70 is mounted on the second portion 48. The gap between the cover plate 70 and the fluted plate 64 is the outlet 68 of the condensate collector 30 at the rear guide surface 42 of the guide vanes 28.

Due to the pressure difference between the inlet at the front guide surface of the guide vane and the outlet at the top end of the guide vane or at its rear guide surface, a portion of the flue gas is drawn into the inlet of the condensate collector as part of the gas flow, in which the condensate film flowing over the top end of the first portion is collected, as well as other liquid droplets deposited within the condensate collector.

This pressure differential may be increased by providing a back plate 72 as the rear guide surface 42 that is attached at its lower end 74 to the lower end of the front guide surface 40 and at its top end 76 to the fluted plate 64. The back plate 72 is curved such that the guide vanes 28 have an airfoil-shaped configuration, resulting in an increased pressure differential (compared to guide vanes where the front and rear guide surfaces are provided by a single plate), a portion of the flue gas flowing along the back plate 72 travels a longer distance than the flue gas flowing along the front guide surface 40.

Fig. 4 shows a further embodiment of a guide vane 28 comprising an additional condensate collector 80 at the lower part of the front guide surface 42. The top condensate collector 30 may be designed as shown in fig. 2 and 3. The additional condensate collector 80 includes a recess 82 in the front guide surface 42 of the guide vane 28. The T-shaped profile element 84 is partly mounted in the recess 82 with its legs 86 at a distance from the bottom 88 of the recess. The top leg 90 of the T-shaped profile element 84 extends over the front surface 42 adjacent the recess 82, thereby forming an inlet and an outlet for the portion of the flue gas stream flowing along the front surface. In the embodiment shown, the recess 82 has a V-shape in front view, so that condensate collected in the recess 82 will flow towards the middle where it is connected to a drain (neither shown).

The trough 62 of the top condensate collector 30 may be designed in a similar manner. Typically, the angle between the legs of the chevrons will be much larger. In an alternative, the groove and/or the recess has an inverted V-shape, such that condensate will flow from the middle of the guide vane to the side of the guide vane, where it is discharged via a connection into a drain.

Fig. 5 shows an embodiment of a wet stack according to the invention provided with a plurality of guide vanes. In the illustrated embodiment, 3 guide vanes 28 are located at the inlet 16. Each guide vane 28 is provided with a condensate collector 30, for example according to the arrangement shown in the preceding fig. 2-4, in particular according to the arrangement shown in fig. 3. Each guide vane 28 has a curved front surface 40, in particular a (first) portion 100 having the shape of a circular arc and a straight top (second) portion 102 parallel to the longitudinal axis of the duct 14. Each guide vane 28 also has as the rear guide surface 42 a rear plate 72 comprising a first (lower) straight portion 104 and a second (upper) straight portion 106 and an intermediate curved portion 108, in particular a circular arc portion having a radius smaller than the radius of the corresponding curved portion of the front guide surface 40. The guide vanes 28 are positioned such that the upstream ends (at the inlet) are equally spaced from each other and their downstream ends define, together with the inner wall 36 (where applicable), almost equal flow areas (flow through great).