BG65258B1 - Device for the separation of solid particles from flue gas in steam boiler with circulating fluidized bed (cfb) - Google Patents

Abstract

The device is used in boilers or reactors for the production of steam for industrial technologies and/or for electric power generation. It contains numerous verticals, striking type, particle separators, made of cooled pipes, and fitted in the CFB boiler in numerous checkered rows. In one embodiment of the device, numerous contact, tightly fitted elements are used, having holes in which the cooled pipes are housed. The contact tightly fitted elements are interconnected in order to form a collector canal, usually of U-shaped form, which separates the particles from the flue gas passing along the particle separators. The overlapping connections in and between the individual contact tightly fitted elements allow their heat expansion and prevent any flow out of the gas and the solid particles. Optionally, the impact-type particle separator (100) include cooled pipes (126), which are interconnected forming a stable intact structure. To the cooled pipes (126), pins are welded having a coating of a refractory material, covered by ceramic bricks, metal or ceramic pulverized coatings, metal or ceramic forms, a welded upper film, and/or screens, securing erosion stability.

Description

(54) Flue gas particulate separator in a steam boiler with a circulating boiling layer

Technical field

The present invention generally relates to circulating fluidized bed steam boilers, and in particular to improved structures of a shock-type particulate separator composed of a plurality of vertical cooled pipes.

BACKGROUND OF THE INVENTION

Circulating fluidized bed steam boiler systems are known and have been used in the production of steam for industrial technology and / or electricity generation. For example, patents US 5 799 593, US 4 992 085, US 4 891 052, US 5 809 940, US 5 378 253, US 5 435 820 and US 5 343 830.

In circulating fluidized bed reactors, reacting and non-reacting solids are entrapped into the housing by the upward flow of gas which carries the particles to the outlet at the top of the reactor, where solids are separated by a shock-type particle separator. The impact type particle separators located in the trajectory of the gas of a circulating fluidized bed steam boiler are closely spaced and horizontally separated from each other in staggered rows. The collected solids return to the bottom of the reactor. Each circulating fluidized bed reactor contains a plurality of vertical impact type particulate separators (or concave reflecting elements and U-shaped reflecting elements) at the outlet of the furnace to separate solid particles from the flue gas stream. Although these separators can have a variety of configurations, they generally represent U-shaped reflective elements, since they most often have a U-shaped configuration in cross section.

When a circulating fluidized bed steam boiler is used, multiple impact type particulate separators are maintained in the furnace housing and arranged vertically in at least two rows around the furnace outlet, the collected particles falling unobstructed, free, naturally to the collecting elements along on the back wall of the housing. The gap between each pair of adjacent U-shaped reflecting elements in one row is centered with the U-shaped reflecting element in the previous or next row of U-shaped reflecting elements, which is a curved trajectory for flue gas / particulate matter. The U-shaped reflecting elements in each row collect and remove particles from the flue gas / solid stream, while the flue gas flow continues to flow around and through the series of U-shaped reflecting elements.

These types of collector elements are usually relatively long in comparison to their width and thickness. The shape of the collector elements is usually dictated by two considerations, namely: the efficiency of collecting the U-shaped reflecting elements and the ability of the U-shaped reflecting elements to be self-supporting. When these elements are used, they are usually located at the outlet of the furnace and are not cooling. Their position at the furnace outlet is to protect the heat transfer surfaces from erosion caused by particulate matter. Therefore, the U-shaped reflecting elements are exposed to high temperatures by the flowing flue gas / particulate matter and the materials used for the U-shaped reflecting elements must be sufficiently temperature-resistant to provide satisfactory resistance to damage.

Long, self-supporting stainless steel sheet ducts have been successfully used in steam boilers with a circulating fluidized bed for the primary particulate collector, but the "bending" strength of the suitable and suitable alloys sold limits the length of the collector elements. By interrupting the long collector channel of the short segment, the required strength of each segment is much smaller than that of the long channel due to the series of intermediate bases and the low weight value of each individual segment or element.

Methods for producing collector elements that are cooled or maintain a cooling structure typically include collector plates welded to water-cooled support pipes (see US 5 378 253 and US 5 435 820), however welding cooling pipes increases the possibility of leakage from the pipe, which happens with welding.

In addition, in this known structural turning, the collector element is cooled asymmetrically due to the proximity of the cooling pipe or pipes to only a small portion of the formed collector channel segment or element. Therefore, the sheet steel forming the collector elements will be susceptible to deformation due to the different stretching of the cooled regions compared to the warmer parts of the collector elements.

In addition, it is necessary to protect the pipes from erosion caused by the impact of solid particles loaded in the flue gas / particulates. This protection requires the use of a pipe made of stainless steel or ceramic, which must be used along the entire height of the collector, which further increases its cost.

SUMMARY OF THE INVENTION

The present invention relates to fluid-cooled tube devices that have been used to form impact type particulate separators, generally in the U-shape, but which can also be formed in the W-shaped, E-shaped, V- figurative or other forms. Such impact type particulate separators are of particular use in steam boilers or circulating fluidized bed reactors.

Accordingly, one aspect of the present invention describes a device for separating solid particles from flue gas in a steam boiler with a circulating fluidized bed. In one embodiment, the apparatus comprises a plurality of vertical impact type particle separators arranged in the gas trajectory of a circulating fluidized bed boiler. Impact type particle separators are closely spaced and horizontally separated from each other in at least two staggered rows. Each impact type of particle separator is made up of a plurality of vertical cooled tubes for carrying coolant through them. The apparatus also includes an additional protective structure for trapping particulate matter from the flue gas / solid stream, which encloses the cooled tubes of the impact type separator. The elements of the protective structure form a collector channel.

Another aspect of the present invention describes a device for separating solid particles from a flue gas in a circulating fluidized bed steam boiler comprising a plurality of vertical impact type particle separators located in the gas path of a circulating fluidized bed steam boiler and an additional protective structure. Impact type particle separators are closely spaced and horizontally separated from each other in at least two staggered rows. Each impact type of particle separator is made up of a plurality of vertical cooled tubes for carrying coolant through them.

The additional protective lathe for trapping solid particles from the flue gas stream consists of a plurality of contact densely assembled elements which, through openings, cover several cooled pipes. The contact elements are interconnected to form a collector channel along the cooled pipes. The collector channel is formed by side walls and a rear wall composed of a plurality of separate vertically arranged segments. Each segment is connected at its ends to the adjacent segment. The plurality of cooled tubes forming a single impact type of particle separator are connected to each other in a straight line by a membrane barrier welded along adjacent cooled pipes with continuous seam. Multiple thumbs can be welded to the pipes and then coated with a heat-resistant material. Other erosion-resistant structures such as ceramic tiles, metal or ceramic spray coats, metal or ceramic molds, screens may be used.

The various novel features that characterize the invention are set forth in detail in the claims appended to and forming part of this description.

Explanation of the annexed figures

For a better understanding of the invention, its advantages and the specific advantages attained in its use serve the drawings which show embodiments of the invention such as:

Figure 1 is a schematic representation of a known circulating fluidized bed steam boiler construction using a shock type particulate separator system;

Figure 2 is a sectional view of a group of U-shaped reflecting elements in a furnace of Figure 1, shown in the direction of arrows 2-2 ';

3 is a top plan view of a first embodiment of a separate U-shaped impact element of a particle type separator according to the present invention;

4 is a view to the right of the U-shaped reflector of the impact type particle separator of FIG. 3, shown in the direction of arrows 4-4 ';

Figure 5 is a rear view of the U-shaped reflector of the impact type particle separator of Figure 3, depicted in the direction of arrows 5-5 ';

6 is a top plan view of a second embodiment of a separate U-shaped impact element of a particle type separator according to the present invention;

Figure 7 is a left view of the U-shaped impact particle-type particle separator of Figure 6, depicted in the direction of arrows 7-7 ';

Figure 8 is a rear view of the U-shaped reflector of the impact type particle separator of Figure 6, depicted in the direction of arrows 8-8 ';

Figure 9 is a view to the right of the U-shaped reflector of the impact type particle separator of Figure 6, depicted in the direction of arrows 9-9 ';

10 is a top plan view of a third embodiment of a separate U-shaped impact element of a particle type separator according to the present invention;

Figure 11 is a left view of the U-shaped reflector of the impact type particle separator of Figure 10, depicted in the direction of arrows 11-11 ';

Figure 12 is a rear view of the U-shaped reflector of the impact type particle separator of Figure 10, depicted in the direction of arrows 12-12 ';

13 is a view to the right of the U-shaped reflector of the impact type particle separator of FIG. 10, depicted in the direction of arrows 13-13 ';

Figure 14 is a side view of another embodiment of a U-shaped reflection particle type impactor device according to the present invention;

Figure 15 is a cross-sectional view of an individual U-shaped reflection element of the impact type particle separator of Figure 14, depicted in the direction of arrows 15-15 ';

Figure 16 is a side view of the bottom of Figure 14;

17 is a cross-sectional view of the underside of a U-shaped impact particle-type particle separator of FIG. 16, depicted in the direction of arrows 17-17 ';

18 is a side view of an alternative embodiment of the U-shaped impact particle type separator of FIG. 14;

Figure 19 is a side view of an alternate embodiment of the upper part of the U-shaped impact particle type separator of Figure 14;

20 is a cross-sectional view of a shock-type particle separator illustrating staggered V-shaped collector elements;

Figure 21 is a side view of an alternative embodiment of the present invention using a chevron collector element;

Figure 22 is a cross-sectional view of the configuration of the chevron collector element of Figure 21, depicted in the direction of arrows 22-22 ';

Figure 23 is a cross-sectional view of a separate chevron collector element of the type illustrated in Figures 21 and 22;

Figure 24 is a cross-section of a deflection plate that can be used in the configuration of the chevron collector element of Figures 21 and 22, depicted in the direction of arrows 24-24 ';

25 is a schematic cross-sectional view of an individual U-shaped impact element of a particle type separator, wherein the cooling tubes are omega tubes according to the present invention;

Figure 26A is a cross-sectional view of an individual omega tube of the type used in the embodiment of Figure 25;

FIG. 26B is a cross-sectional view of an alternative embodiment of the omega tubes in the embodiment of FIG. 25 using ordinary tubes and membrane barriers; FIG.

Figure 27 is a cross-sectional view of two connected tightly assembled contact forms that can be provided above the cooling tubes forming a separate U-shaped impact element of a particle-type separator to improve the erosion resistance of the present invention;

Figure 28 is a cross-sectional view of a separate U-shaped impact element of a particle type separator, wherein the cooled tubes are provided with protective molds attached thereto to improve the erosion resistance of the present invention;

Figure 29 is a cross-sectional view of a portion of a separate U-shaped impact element of a particle type separator, wherein the cooled tubes are provided with bolted fasteners to improve the erosion resistance of the present invention;

FIG. 30 is a side view of a portion of the individual U-shaped impact type particle separator of FIG. 29, depicted in the direction of the arrows 30-30 'in FIG. 29; FIG.

31 is a cross-sectional view of an alternative embodiment of a staggered array of chevron collector elements according to the present invention;

Figure 32 is a cross-sectional view of an individual chevron collector element of the type illustrated in Figure 31 provided with an erosion-resistant refractory material according to the present invention;

Figure 33 is a cross-sectional view of an individual chevron collector element of the type illustrated in Figure 31 provided with a stainless steel enclosure that promotes erosion resistance according to the present invention;

34 is a cross-sectional view of a separate chevron collector element of the type illustrated in Figure 31, wherein the cooled pipes are surrounded by cast metal to improve the erosion resistance of the present invention;

Figure 35 is a top plan view of an alternative embodiment of a separate U-shaped impact element of a particle type separator comprising a rectangular cooling fluid conduit system according to the present invention;

Figure 36A is a perspective view of the bottom of an individual U-shaped particle-type impactor reflector element according to the present invention, wherein the lower edges of adjacent cooled tubes are fluidly connected to each other to form 180 ° curves;

Figure 36B is a perspective view of the bottom of an individual U-shaped reflection element of a impact type particle separator according to the present invention, wherein the lower edges of the cooled tubes forming opposite sides of the U-shaped reflection element are fluidly connected to each other, to form 180 ° curves;

Figure 37 is a perspective view of the underside of an individual U-shaped particle type impactor reflector according to the present invention, wherein the lower edges of the cooled tubes are fluidly connected to a common manifold located approximately above the level of the gas path;

38 is a side elevation view of an individual U-shaped particle type impactor reflector according to the present invention, wherein the lower edges of the cooled tubes are fluidly connected to a common manifold located approximately below the level of the gas path;

39 is a perspective view of yet another alternative embodiment of a separate U-shaped impact element of a particle type separator according to the present invention, wherein the lower part of each cooled pipe is provided with a reduced diameter portion which prevents erosion of the lower part.

Examples of carrying out the invention

As used herein, the circulating fluidized bed boiler may also be referred to reactors or combustion chambers with a circulating fluidized bed where the combustion process takes place. Although the present invention is specifically directed to steam boilers or steam generators that use circulating fluidized bed combustion chambers as means by which heating is achieved, it will be understood that the present invention can easily be used in another type of circulating fluidized bed reactor fluidized bed. For example, the invention may be applied to a reactor that is used for chemical reactions other than the combustion process, or where a gas / solid mixture from the combustion process occurring elsewhere is provided to the reactor for further treatment, or where the reactor provides only a hull where particles or solids are entrapped in a gas that is not a required by-product of the combustion process. Also, the term U-shaped reflector is used for convenience and is obviously intended to refer to any type of concave reflecting element or impact type particle separator used to collect and remove particles from the flue gas stream. In particular, the impact type of particle separators are non-uniform, they may be U-shaped, V-shaped, E-shaped, W-shaped, or of any other shape, having a concave or cup-shaped surface; which is directed to the incoming flue gas stream and the charged particles, the surface of which will allow the elements to collect and remove the flue gas particles.

Explaining the drawings in which the same positions are used to indicate the same or functionally similar elements throughout the individual drawings, Figure 1 shows a steam boiler or furnace generally denoted by heading 10 containing a circulating fluidized bed 12, a convective passage 14, and hollow elements 16. The combustion of fuels in the circulating fluidized bed 12 generates hot waste or flue gas which is loaded with said substances. The hot gases rise through the furnace 10 to the convective passage 14, from which the gases pass transversely and / or through several heat exchange surfaces (such as an overheater, heater or economizer) 17 and cleaning stages before being discharged to the atmosphere (not shown).

Rows of checkered impact type particle separators 20 are oriented at the top of the furnace 10 and are generally supported by the furnace roof 26. A first group of 22 particle separators of U-shaped reflecting elements is directed to the interior of the furnace, while a second group of 24 particle separators is provided and located downstream of the furnace outlet, which is schematically represented by the broken vertical line in Figure 1 shown between groups 22 and 24. The said flue gas substances are impacted by the impact type particulate separator 20, causing separation and free fall directly back into the circulating fluidized bed 12, where additional combustion or heap reaction may occur. the reactants. Typically, the impact type particle separators 20 are non-linear and preferably U-shaped in cross-section, but they may be V-shaped, E-shaped, W-shaped or some of a suitable concave or cup-shaped construction.

Figure 2 is a sectional view of a U-shaped reflection element 20 in a furnace forming the inner group 22 of a U-shaped reflection element 20 and illustrates how the rows of U-shaped reflection elements 20 are staggered relative to each other in adjacent rows. At the bottom of each U-shaped reflection element 20, there is usually a tray-forming plate or partition 23 in the inner group 22, which is intended to prevent flue gases and charged particles from leaking from the U-shaped reflection elements 20.

Referring to FIGS. 3, 4 and 5, it is apparent that there is illustrated a first embodiment of a U-shaped reflection particle type impactor 20 in accordance with the present invention. Each U-shaped reflection element 20 is composed of cooled tubes 30 that can be cooled by water, water vapor, a mixture of them, or some other similar refrigerants. The cooled pipes 30, and therefore the U-shaped reflecting elements of which they form a part, are mounted vertically, similar to the known U-shaped reflecting elements 20, illustrated in Figure 1, and can be held below the roof 26 of the furnace 10. The cooled tubes 30 forming a separate U-shaped reflection element 20 are stacked side-by-side and as illustrated in Figure 3, four cooled pipes 30 can be used to form a separate U-shaped reflection element; one at each of its angles. Cooled tubes 30 are typically of external diameter 1, but of course tubes of other diameters may be used.

As illustrated in Figures 3,4 and 5, each U-shaped reflection element 20 further includes a plurality of contact densely assembled elements 50 having openings 52 in part 57 (which may be an expanded portion as shown to cover the cooled tubes 30 received at this location) and which receives each of the cooled tubes 30 forming a separate U-shaped reflecting element 20. In this way, the contact tightly assembled members 50 enclose each cooled tube 30 and by stacking one another along the vertical height of the U- figurative reflections body elements 20 form a collector channel 60. Each tightly assembled contact member 50 forming the U-shaped reflection element 20 includes two side walls 54 and a rear wall 56. As illustrated in Figures 4 and 5, each of the side walls 54 and the rear wall 56 is made up of a plurality of vertically arranged straight segments 70 extending between portions 57 containing openings 52 enclosing the cooling pipes 30. The vertically arranged segments 70 of the plurality of contact densely assembled members 50 are arranged along a length of the vertically extending chilled tubes 30 and combined with each other to form the collector channel 60 of the U-shaped reflecting elements 20.

Overlapping links 80 or any similar type of connection are provided between vertically arranged straight segments 70. Overlapping connecting configuration 80 at the top and bottom of each vertically arranged segment 70 prevents gas and solids from flowing between segments 70 and allows for a short period and for a long period expansion and contraction of segmental dimensions in a vertical direction.

Therefore, the cooled tubes 30 provide a cooling column, also aligning and cooling the stacked segments 70.

The cooled tubes 30 further provide an extremely symmetrical temperature distribution along each straight-line segment 70 without deforming the shape of the element that will normally be covered when asymmetric temperature distribution occurs due to asymmetric cooling of the segment 70.

Each tightly assembled contact member 50 may be composed of a metal alloy, ceramic or other materials with high heat resistance. In the embodiment of Figures 3, 4 and 5, each of the tight-fitting contact members 50 consists of a single integral part, which contains both side walls 54 and a rear wall 56, and which slides over the cooled pipes 30. The separate whole may be molded or extruded. However, it will be appreciated that other constructions for tight-fitting contact members may be used.

Referring now to Figures 6, 7, 8 and 9 of another embodiment, each of the side walls 54 and the rear wall 56 are separate contact dense assemblies; therefore, three separate dense contact elements are required to form a single horizontal plane or cross section of the U-shaped reflecting element 20. The end portions 57 and their openings 52 on each side wall 54 and the rear wall 56 overlap at transport links 80.

Referring to Figures 10, 11, 12 and 13 of yet another embodiment, the side walls 54 and the rear wall 56 may be formed by two elements 59 having an L-shaped cross-section. The ends of the L-shaped members 59 are overlapped at the rear wall 56 by the overlapping link 80.

As illustrated in the embodiments of Figures 6 and 10, additional chilled tubes 30 may be used, which are flush with the four chilled tubes shown in Figure 3, to form a column and cool the collector ducts. Such construction may also be used if a larger size of the U-shaped reflecting elements 20 is required or if different cooled tubes are required 30. These means can be used to provide low heat resistance of the material forming the contact tightly assembled member 50 , taking into account the extremely symmetrical temperature distribution along the vertical height of each U-shaped reflection element 20.

Although the aforementioned patents US 5 378 253 and US 5 435 828 disclose cooled collector elements, the constructions herein do not present the significant practical difficulties encountered in using the many advertised applications. As shown, each separator element consists of only four cooled separator tubes with a welded membrane bar extending between the tubes to form the collector portion. This severely restricts the use of such structures for two reasons. First, the temperature limit of oxidation of the membrane barrier is found to limit the maximum width of the membrane barrier when the separator elements operate at temperatures tested in a circulating fluidized bed.

Although the membrane barrier is cooled by the pipes to which it is attached, the maximum temperature of the membrane barrier occurs in the middle of the pipes connected through the membrane, and at this location the temperature must be maintained to acceptable levels below the temperature limit for oxidation of the material, forming a membrane barrier. While this aspect may be attributed to the use of an alloy barrier having a higher temperature limit for oxidation, or even the use of stainless steel tubes and a membrane barrier, it will be understood that this leads to a very high cost. In fact, the constructor still cannot afford much to increase the maximum width of the membrane barrier. The second reason, as a result of limiting the maximum width of the diaphragm barrier, is that the actual size of the individual collector elements may be limited by what is needed for productive and cheap collector performance.

In contrast; the following embodiments of the present invention use at least three or more chilled pipes 126 on each side of the individual separator elements 120 together with the corresponding number of chilled pipes 126 forming at the rear of each of the elements 120. Therefore, the size of the separator elements 120 is not limited by the maximum temperatures the diaphragm and separator elements 120 can be constructed as large as necessary. This is important because the use of larger separator elements 120 allows longer separators to be used. The larger cross-section of a separate separator element allows a greater amount of solids to remain "inside" the cross-section before the collected solids "spill" due to the overflow of the moving solids to the lower part of the separator element 120. In other words, the separator element 120 has a longer effective portion. The use of longer separator elements 120 means that it will be less necessary for the used steam boiler with a circulating fluidized bed to be narrower (although the depth of the furnace may be greater for a given cross-sectional area) which reduces the price.

Figures 14 to 24 inclusive illustrate another embodiment of a U-shaped reflector of the impact type particle separator according to the present invention, usually designated by heading 100, which is particularly suitable for use in steam boilers with circulating fluidized bed. Again, the term U-shaped reflecting element is used for convenience and means any type of concave reflecting element or impact type particulate separator used to collect and remove particles from the flue gas / particulate stream. In particular, the impact type of particle separators is not planar: they can be U-shaped, V-shaped, E-shaped, W-shaped or any other shape in which they have a concave or cup-shaped surface that is directed to the incoming smoke stream gas and solids, which will allow the elements to collect and remove the flue gas particles.

The particle separator 100 is composed of a plurality of vertically extending checkerboard U-shaped reflector elements 120 arranged in at least two rows - upper row 122 and lower row 124. The device 100 can be used as a group of internal U-shaped reflectors elements 22 or as external U-shaped reflecting elements 24. The U-shaped reflecting elements 120 are composed of a plurality of cooled pipes 126 that carry a refrigerant such as water, water vapor, a mixture thereof, or other similar suitable refrigerant. luid. The cooling fluid is transferred into or out of the U-shaped reflecting elements 120 through a system of pipes, reservoirs and collectors located in the upper 128 and lower 130 parts of the device 100. As will be later fully disclosed, the special device of such a pipe system , reservoirs and collectors for the U-shaped reflecting elements 120 forms an important aspect of the present invention.

Referring back to Figure 15, there is shown a cross-section of a separate U-shaped impact element of the impact type separator element 120 of Figure 14. Multiple cooled pipes 126 are arranged in order to form the general outline of the collector element , in this case a U-shaped collector reflector. A total of 12 cooled pipes 126 are used, but more or less pipes 126 may be used depending on the size of the desired U-shaped reflecting element, the type of cooling fluid as well as the drop pressure, etc. Each cooled pipe 126 in the U-shaped reflection element is provided with a plurality of fingers 132 welded to the pipes 126 along their length and around their periphery, which allows the use of heat-resistant material 134 in the U-shaped reflection element 120. The individual pipes 126 forming a given U-shaped reflect The flax element is also connected to one another via an intermediate tube or barrier (e.g., membrane barrier 136), welded continuously to one another and along adjacent cooled tubes to maintain the U-shaped reflection element 120 as a whole, stable structure. The diaphragm partition 136, also the thumbs 132, conduct the heat from the heat-resistant material 134 to the cooled pipes 126, the conduction being by an internal flowing coolant, usually water and / or water vapor. The heat-resistant material 134 can be pre-fabricated into the U-shaped reflecting elements 120, which reduces the cost and provides a uniform layer or can be put in place.

Figure 16 illustrates a side view of the bottom of Figure 14; in particular, a first embodiment of a system of pipes, a sump, and a collector that can be used to supply cooling fluid to or from the U-shaped reflecting elements 120. The lower ends of the cooled pipes 126 are fluidly connected to a plurality of vertical collectors 138 which are fluidly connected to the manifold 140. In addition, the device can be configured as an inlet catch 140 and associated inlet manifolds 138, or as an outlet water collector 140 and outlet manifolds 138. In the device illustrated in Figure 16, both rows 122,124 o m U-shaped reflecting elements 120 are part of the same module; they are powered by the same collector 138. The size of the circulating fluidized bed steam boiler and the permissible load limits will determine the number of individual U-shaped reflecting elements 120 that can be collected at the plant and loaded for the installation site. The inlet or outlet pipe system 144 will be used and delivered as required.

Figures 16 and 17 illustrate another aspect of the present invention. Embodiment includes the use of a cooled tube 126 curved appropriately to form a tray or barrier 142 at the lower end of the U-shaped reflecting element that helps to protect the gas carrying solid particles from overflow around the lower U-shaped portion 130 reflective elements 120. The fluid-cooled tray 142 is also provided with thumbs 132, which are also coated with a heat-resistant material 134. If necessary, a standard tray or barrier may be used at the lower edges of the U-shaped reflective elements 120, according to astoyashtoto invention.

Figure 18 illustrates a side view of an alternative embodiment of the lower portion of the U-shaped impact particle type separator of Figure 14; in particular a device wherein the front 122 and the rear 124 rows of U-shaped reflecting elements 120 are fluidly connected to a separate collector 138 for each row. The objectives mentioned previously relate to the possibility that the lower portion 130 is the inlet or outlet for the coolant flowing into the U-shaped reflecting elements 120 used.

Figure 19 illustrates a side view of the upper portion 128 of the alternative embodiment illustrated in Figure 18. Here, separate input or output collectors 138 will be used, one for each row 122,124 of the U-shaped reflecting elements 120 connected to a suitable input or output system of pipes 144 as shown.

Figure 20 is a cross-sectional view of a shock-type particle separator according to the invention, illustrating a staggered arrangement of V-shaped collecting elements. In addition, each cooled pipe 126 is provided with a plurality of pins 132 welded to the pipes 126 along their length and around their periphery, which allows the use of the heat-resistant material 134 of the collector element 120. The individual pipes 126 forming a collector element 120 are also connected to one another by a membrane barrier 136 welded at least in the middle between the pipes 126 to maintain them as a stable structure. The diaphragm barrier 136 as well as the thumbs 132 conduct heat from the gas-resistant material 134 to the cooled pipes 126, where it is transmitted through the internal flow of the coolant, usually water and / or water vapor. The heat-resistant material 134 may be pre-fabricated to reduce cost and ensure uniformity of the layer, or may be in place.

Figures 21 to 24 illustrate an embodiment of the present invention which utilizes a device generally referred to as chevron collector elements 150 (commonly known as screens in our country). The cooled pipes 126 are again provided with a plurality of thumbs welded to the pipes 126 along their length and around their periphery, which allows the heat-resistant material 134 to be used by the chevron collector elements 150.

The individual tubes 126 forming a chevron collector element 150 are also connected to one another by a membrane barrier 136 welded at least midway between the tubes 126 to maintain them as a stable structure. The diaphragm barrier 136 and the thumbs 132 also conduct the heat from the heat-resistant material 134 to the cooled pipes 126, where it is transmitted through the internal flow of the coolant, usually water and / or water vapor. The heat-resistant material 134 may be pre-fabricated to reduce costs and provide uniform application, or may be applied locally. The chevron collector elements 150 may optionally be provided with one or more deflection plates 152 arranged at intervals along the vertical height of the chevron collector elements 150. The deflection plates 152 are designed to direct the collected solids back to the chevron collector elements 150 The preferred connection is by welding a first part 154 of the chevron collector element 150, which extends substantially parallel to the flue gas and particulate matter when fed e.g. p in a circulating fluidized bed steam boiler and a second part 156 which is connected and extends at an angle of 0 to the first part 154. The angle 0 is usually about 30 °, but it can be varied from about 10 ° to about 90 ° to adapt to the special application.

Although the second part 156 illustrated in Figures 22 and 23 is shown as a plane, the present invention is not so limited and the second part 156 can alternatively be arcuate or split and angled, as illustrated in A and B in figure 23 through broken lines.

Figure 23 illustrates separate V-shaped chevron collector elements 150. These collector elements 150 in a straight line to each other (with respect to the predominant direction of the flue gas and solids through these elements 150) can be connected at the ends of the first parts 154, as shown in C, or they can be separated from each other.

The present invention also encompasses various constructions that improve the erosion resistance of the cooled U-shaped impact elements of the impact type particle separators described herein. In Figure 25, the cooled tubes form a separate U-shaped reflection element 120, which is made by omega tubes 160 welded together, as illustrated by heading 164, to form a U-shaped reflection element with the desired cross-sectional configuration . In the embodiment shown, the dimensions of the omega tube may be 1 - 3/8 at 1 with a minimum wall thickness of 3/16. Although such omega tubes 160 are known to the person skilled in the art, it is not yet known that they have been used in such a U-shaped impact element of a particle type separator. As shown in Figure 26A, each omega tube is provided with a flow channel 161 and ends 166 provided with bevelled parts, which facilitates welding 164 of adjacent omega pipes. Omega tubes can be efficiently filled using standard pipes 126 and membrane baffles 137 welded coronally to the pipe, as shown in Figure 26B.

Figure 27 illustrates a device of two contact tightly assembled molds 170 having openings 162 that will also accommodate the cooled pipes 126. The tightly assembled molds 170 have " male parts " 172 and " female parts " 174 that facilitate the straight line alignment of adjacent molds. . These shapes will usually be made of low alloy steels, but they can be coated with an '309 alloy to improve erosion resistance.

Figure 28 illustrates a device of protective molds 180 that will be welded to the cooling pipes 126, preferably by electrodeposition, as illustrated in 184. Molds 180 will have a 3/4 (0.64 cm) additional face, except for the guide an edge where the 182 shape will be provided with 1/2 (1.27 cm) additional face. As shown, the backs of each type of mold will be curved to connect to the outside diameter of the cooled pipe to which the mold will be attached.

Figures 29 and 30 illustrate a device of protective molds 190, which are configured as a bolt 194 passing through a U-shaped reflective element of impact type particle separators, preferably through a membrane 136 or an intermediate metal tube to line the plates holding the tubes 126 near side by side. In the molds 190, holes 192. will be provided. In the other case, it is preferable for the molds to release the diaphragm or the intermediate tube for arranging the plates. If necessary, the bolts 194 may be replaced by thumbs welded to each side of the diaphragm or intermediate tube for alignment of the plates. Forms at the leading end (not shown) will preferably be joined by one-way electrical wiring, as described previously.

Figures 31 and 32-34 illustrate an alternative embodiment of a staggered chevron collector element according to the present invention and various ways that provide improved resilience to this embodiment. In addition, a staggered arrangement of impact type particle separators is provided, which, this time, are arranged in a straight line with groups of cooled pipes 126 interconnected as above (intermediate tube for arranging plates or membranes 136). Plates 200 are welded at regular intervals to the cooled pipes 126 to provide a curvilinear trajectory of the incoming flue gas / particulate stream. Cooled pipes can be provided with an erosion-resistant refractory material (Figure 32); stainless steel cooling bulkhead 202 (Figure 33) (with slots at a distance, if necessary); or they may be covered by cast metal or welded coating 204 (Figure 34).

Figure 35 illustrates another embodiment of a separate U-shaped reflection element of a shock-type particle separator 120, this embodiment consisting of rectangular tubes 210 for carrying the cooling fluid of the present invention. The individual tubular members 210 will be welded to each other by welding 212 as shown. Preferably, the rectangular tubes 210 can be made of carbon steel (SA-178 Gr. C) and are so long that the cooling fluid, carried through them, keep the metal temperature below the limit of plastic deformation (more greater than 370 ° C) (700 ° F) for carbon steel.

Figures 36A, 36B, 37 and 3 8 illustrate a specific construction of details of the lower edges of the individual U-shaped impact element of the impact type particle separators 120 according to the present invention. For clarity, no erosion protection is indicated for the cooled pipes 126 or for any collector 138, but it will be understood that such erosion protection will, of course, be provided in actual operation. As described in U.S. Pat. No. 6,095,095, structures are known in a circulating fluidized bed steam boiler in which at least two rows of external U-shaped reflecting elements can be housed in the exhaust gas duct 14 located after the furnace exit, such as the collected particles are returned in the direction of level 220 (Figures 36A, 36B, 37 and 38 of the present invention). In addition, the walls 222, 224 and the rear 226 of the U-shaped reflecting elements 120 are composed of cooled pipes 126.

The lower ends 228 of the cooled pipes 126 may be fluidly connected in various ways. For example, as illustrated in Figures 36A, 36B, 37 and 38, the lower edges 228 of the cooled tubes 126 extend approximately to the level 220, located immediately below the staggered row of impact type particle separators. Level 220 forms the trajectory of the gas from the steam boiler 10. In some cases, as illustrated in Figure 36A, the lower ends of adjacent cooled pipes 126 (such as those forming one wall or the other 222,224 or rear 226) forming the impact type of separators 120 particles are fluidly coupled to each other to form 180 ° curves. Alternatively, as illustrated in Figure 36B, the lower ends 228 of the cooled pipes 126 forming opposite walls 222,224 of the impact type particle separators 120 are fluidly connected to each other to form 180 ° curves. These embodiments are relatively simple in construction, but it will be understood that they make the cooled impact type particle separators 120 without the possibility of drainage.

As illustrated in Figure 37, the lower ends 228 of the cooled pipes 126 forming a separate impact type separator 120 of the particles are fluidly connected to a common manifold 138 located approximately to the level 220 of the gas flow path 14, in which case it is above level 220, while figure 38 illustrates an embodiment wherein the manifold 138 is located below level 220. It is clear that the common manifold 138 can actually be partially or fully placed at level 220. Although more complex, this construction allows separators 120 to be drained and cm removing the cooling fluid from each of the cooled pipes may provide another advantage, for example, eliminating the temperature imbalances due to the unequal thermal absorption of the individual cooled pipes 126. Also, the construction illustrated in Figure 38 allows better access to any weld of cooled pipes 126 to manifold 138 if necessary.

Finally, Figure 39 is a perspective view of yet another alternative embodiment of a separate U-shaped reflection element of the impact type separator 120 of particles according to the present invention, wherein the lower part 228 of each of the cooled pipes 126 is provided with a reduced diameter portion 250 to prevent erosion of the lower portion 228. This embodiment uses variants of the ideas used in US 6 044 805, entitled "Downstream Wall Solids Protection" and of published application WO 2000/068615, as the text of these publications is included herein by reference in its entirety, as explained herein. In these publications, a reduced diameter portion was used to remove the interrupted normal presence at the separation surfaces of the housing and the common wall of the structures. However, as shown in Figure 39, the lower portion 228 of each of the cooled tubes 126 is provided with a reduced diameter portion or zone 250 to prevent erosion of the lower portion 228 of the U-shaped reflecting elements 120. To accomplish this, modification, the outer diameter of each tube 126 is stamped at its lower end 260 to reduce the diameter. As required and as disclosed in the aforementioned US 6 044 805 and WO 2000/068165 publications, a shaped refractory tile 270 is provided at the passage 250 and, due to its presence, the erosion-resistant refractory material may be removed or not used. Under the reduced diameter portion 250, an erosion-resistant refractory 134 may also be provided downstream of the end of each U-shaped reflection element 120.

Therefore, it is clear that any U-shaped impact element of the impact type separator may be composed of cooled tubes that are connected to each other to support the tubes against each other. In some embodiments, the pipes are joined or connected in a straight line by an intermediate tube or barrier, interrupted welded at least between and along adjacent cooled pipes, to form a single stable structure. Deflection plates designed to direct the collected solids back to the collector element, similar to the plate 152 of Figure 24, can be used in each embodiment of a separate U-shaped impact element of a particle type separator. In all embodiments, it is necessary to protect the cooled pipes from the impact type separating elements of erosion and corrosion particles. Different means can be used to protect the pipes from erosion; in some cases, tightly assembled contact forms are used over cooled pipes, in other cases materials such as ceramics or refractories are attached to erosion protection pipes. As disclosed above and illustrated in the figures forming part of this description, in some embodiments of the invention, the attached inlet and outlet lines and connections that carry fluid to and from the pipes are considered an important feature of the invention. In some cases, the inlet and outlet connections determine the degree of modularity with which the impact type of particle separator can be provided, thus speeding up installation and reducing costs. In other cases, some portions of such joints actually form and perform the functions of trays and barriers used in conjunction with those U-shaped reflecting elements that protect the gas encircling the edges of the impact type separator elements. It will be appreciated that commonly known non-refrigerated metal trays or bulkheads may be provided with any of the aforementioned configurations of the present invention.

The present invention can be applied to both a new structure comprising circulating fluidized bed reactors or combustion chambers and to the replacement, repair or modification of existing circulating fluidized bed reactors or combustion chambers.

Claims

Claims (24)

1. A device for separating particulate matter from a flue gas stream into a circulating fluidized bed steam boiler comprising a plurality of vertical impact type separators arranged in the gas path of a circulating fluidized bed steam boiler, the impact type particulate separators being placed close together and horizontally separated from each other in at least two staggered rows, wherein each impact type of particle separator is made up of a plurality of vertical cooled tubes for carrying coolant through them, interconnected, characterized by It further comprises an additional protective structure for trapping solid particles from the flue gas / solid stream, comprising cooled tubes (30,126,160,210) of the impact type separator, wherein the elements of the protective structure form a collector channel (60,138, 140). A device according to claim 1, characterized in that the additional protective structure consists of a plurality of contact densely assembled elements (50) enclosing several cooled pipes (30) through openings (52), the contact elements (50) being interconnected so as to form a collector channel (60) along the cooled pipes (30) formed by side walls (54) and a rear wall (56) composed of a plurality of separate vertically arranged segments (70), each segment ( 70) is connected at its ends to the adjacent segment (70). Device according to claim 2, characterized in that a cover-transfer link (80) is provided between the vertically arranged segments (70). Device according to claim 2 or 3, characterized in that the end portion (5 7) of the side wall (54) is connected by overlapping with the end part (57) of the rear wall (56), wherein the end portions (57) ) intersect at the cover-transfer link (80). A device according to claim 2, characterized in that the side walls (54) and the rear wall (56) are formed by 2 elements (59) having an L-shaped cross-section, the ends of which overlap at the roof-transfer connection (80). Device according to claim 2, characterized in that the contact elements (50) are made of metal or ceramics. Device according to claim 1, characterized in that the additional protective structure comprises a plurality of cooled pipes (126) forming a separate impact type separator and connected to each other, wherein at least one of the cooled pipes (126) is curved and directed to the bottom of the individual impact type separator forming tray (142), protecting the gas and overflow particles around the lower part (130) of the impact type separator. Apparatus according to claim 2 or 7, characterized in that the vertical impact type particle separators have a cross section of a U-shaped, E-shaped, W-shaped, V-shaped or similar concave or cup-shaped configuration. Device according to claim 7, characterized in that the plurality of cooled pipes (126) forming a separate impact type particle separator are connected to each other in a straight line by a membrane barrier (136) welded along the adjacent cooled pipes (126) with continuous seam. A device according to claim 1, characterized in that the additional protective structure comprises a plurality of cooled pipes (126) connected to each other and forming a separate impact type separator shaped as a chevron collector element (150). Apparatus according to claim 10, characterized in that the chevron collector element (150) comprises rods (132) welded to the cooled pipes (126) at regular intervals, providing a curvilinear trajectory of the flue gas / particulate stream. Apparatus according to claim 7 or 10, characterized in that the cooled pipes (126) are fluidly connected at the top and bottom (128, at least in two rows (122,124)). 130) of the impact type separators to a common manifold (138). Apparatus according to claim 7 or 10, characterized in that the cooled pipes (126) in at least two rows (122, 124) are fluidly connected at the upper and lower parts (128,130) of the impact type separators to separate collectors (140) . A device according to claim 10, characterized in that the chevron collector element (150) has a first part (154) disposed parallel to the flue gas / particulate stream and a second part (156) which is connected with the first part (154) and is at an angle of 0 with respect to it. A device according to claim 14, characterized in that the angle 0 is in the range from about 10 ° to about 90 °. Device according to claim 14, characterized in that at least one deflection plate (152) is located between the first (154) and the second (156) parts. Device according to claim 14, characterized in that the first parts (154) of the chevron collector elements (150) are connected in series, forming separate parallel trajectories for the flue gas / particulate stream. A device according to claim 10, characterized in that the chevron collector element (150) has a first portion (154) disposed parallel to the flue gas / particulate stream and a second portion (156) which is connected to the first part (154) and has a shape that is arcuate or segmented. Apparatus according to claim 1, characterized in that omega tubes (160) are used as cooled tubes forming the impact type of separators. Apparatus according to claim 1, characterized in that rectangular tubes (210) are used as cooled tubes forming the impact type of separators. A device according to claim 1, characterized in that the lower part (228) of the cooled tubes (126) is provided with a reduced diameter die portion (250) preventing erosion of the lower part (228). Apparatus according to claim 21, characterized in that the small diameter portion (250) of each of the cooled pipes is covered with ceramic tiles. A device according to claim 21, characterized in that the part, located below the reduced diameter part (250), contains an erosion device and a heat-resistant material. A device according to any one of claims 1 to 21, characterized in that the plurality of vertical chilled pipes are provided with an erosion-resistant construction comprising at least one of: a plurality of fingers welded to the chilled pipes and coated with a heat-resistant material, ceramic tiles, metal or ceramic atomized coatings, metal or ceramic molds, screens. Attachment: 39 figures