circulating fluidized bed

Abstract

The present invention discloses a circulating fluidized bed, comprising a furnace and a plurality of air distribution ducts. The furnace has a chamber, a feed port, and a discharge port. The feed port and the discharge port are both connected to the chamber. The discharge port is located at the bottom of the furnace and is spaced apart from the feed port in a vertical direction. The plurality of air distribution ducts are located within the chamber and between the feed port and the discharge port. The plurality of air distribution ducts are spaced apart along a first direction to form a discharge channel. At least a portion of the discharge channel is vertically opposed to the discharge port so that large particles of material can flow into the discharge port through the discharge channel. The air distribution ducts include a duct body and a plurality of nozzles. The nozzles are spaced apart in multiple rows along the circumference of the duct body. The duct body has a first section and a second section extending in a second direction and connected to each other. The first section and the second section are symmetrical about the center of the duct body. The circulating fluidized bed of the present invention has the advantages of simple structure, low cost, and high combustion efficiency.

Description

Technical Field

[0001] The present invention relates to the field of boilers, and in particular to a circulating fluidized bed. Background Art

[0002] A circulating fluidized bed suspends a large number of solid particles in a moving fluid, so that the particles have certain apparent characteristics of the fluid. This fluid-solid contact state is called solid fluidization.

[0003] In the related art, the circulating fluidized bed has uneven air distribution and low combustion efficiency. Summary of the Invention

[0004] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0005] The coarse particles in the slag of the circulating fluidized bed that remain in the furnace will seriously affect the fluidization and combustion process in the circulating fluidized bed. In the mildest case, local fluidization will occur, and in the worst case, the normal operation of the boiler will be endangered. The fine particles in the slag have a significant promoting effect on the heat and mass transfer in the circulating fluidized bed. In actual process, it is necessary to ensure the stock of fine particles in the bed as much as possible. The traditional slag discharge method chooses to drill slag discharge holes on the air distribution plate, and use methods such as tilting the air distribution plate or installing a directional wind cap on the air distribution plate to transport the slag to the slag discharge hopper to complete the slag discharge process in the furnace. However, this process will inevitably cause the loss of air distribution uniformity and easily lose a large amount of fine particles, resulting in material loss in the furnace, which in turn has an adverse effect on the fluidization and combustion process in the furnace. At the same time, slag with a wide particle size distribution can easily clog the slag discharge holes on the air distribution plate, which directly leads to slag discharge difficulties and the size of the slag discharge holes is difficult to select.

[0006] In addition, the coarse particles in the slag discharge have poor heat transfer due to their large particle size and low comprehensive heat transfer coefficient, which will lead to an increase in the demand for heat exchange area in the subsequent waste heat recovery part, which will directly lead to adverse effects such as increased investment and cost of waste heat recovery equipment and increased floor space.

[0007] To address the wide-particle slag discharge problem, a feasible solution is to change the original air distribution plate design, redesign the air distribution system and method, achieve slag particle size sorting, smoothly discharge coarse-particle slag, and retain fine-particle slag. Invention patent CN101701762B discloses a pipe-type air distribution device, which is mainly used for fluidized bed hot air drying materials. The air distribution plate body of the invention is composed of an air distribution main pipe and a plurality of air distribution branch pipes. The ends of the branch pipes are sealed and directly connected to the main pipe, and a plurality of air outlet holes are evenly distributed on the lower side. Large particles of material can be discharged from the gaps between the pipes in time to prevent large clumps from accumulating in the fluidized bed, effectively eliminating the channel flow and dead zones formed in the bed layer. However, the equal cross-sectional design of the branch pipes will inevitably have the problem of uneven flow velocity near the air outlet holes of the main pipe. At the same time, the main pipe is arranged just below the branch pipe, occupying part of the slag discharge cross-section; Invention patent CN111780125A discloses a pipe-type air distribution device suitable for fluidized bed incineration of garbage. The invention is used to solve the problem of bottom slag discharge difficulties in fluidized bed incineration of garbage. The air distribution plate adopts an air distribution pipe + hood air outlet design scheme. By reasonably arranging the hood and castables, multiple slag outlets can be evenly arranged on the air distribution plate. The structure is compact and located in the distribution area. The air distribution ducts at the bottom of the air plate can cool the slag and recover sensible heat, but the air distribution ducts described in this invention still have a certain degree of air distribution unevenness due to the use of a multi-air hood design with equal cross-section. At the same time, since the primary air is hot air, the sensible heat recovery effect is limited; Invention Patent CN213453666U discloses a fluidized bed industrial solid waste incinerator with tubular air distribution, which is mainly used to solve the problem that the air distribution plate and air hood in the industrial solid waste incinerator are easily coked and blocked. The invention arranges several layers of fluidized air distribution ducts with gaps inside the conical section of the furnace to remove solid waste particles with large specific gravity and large particles and slag particles produced by combustion. The multi-layer air distribution duct bundles are staggered and the air distribution uniformity is improved by connecting the air distribution plates in parallel. However, since the air distribution ducts are arranged in multiple layers, up to the slag discharge port at the bottom, the waste heat recovery area is occupied. At the same time, due to the uneven heating of air distribution ducts at different heights and the design of air distribution ducts with equal cross-sections, it is conceivable that it will inevitably lead to deviations in the outlet wind speed, limiting its large-scale development.

[0008] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0009] To this end, an embodiment of the present invention provides a circulating fluidized bed with high combustion efficiency and uniform air distribution.

[0010] The circulating fluidized bed according to an embodiment of the present invention includes: a furnace, the furnace having a chamber, a feed port and a discharge port, the feed port and the discharge port are both connected to the chamber, the discharge port is arranged at the bottom of the furnace and is spaced apart from the feed port in the vertical direction; a plurality of air distribution pipes, the plurality of air distribution pipes are arranged in the chamber and between the feed port and the discharge port, the plurality of air distribution pipes are spaced apart along a first direction to form a discharge channel, at least part of the discharge channel is arranged relative to the discharge port in the vertical direction, so that large particle materials flow into the discharge port through the discharge channel, the air distribution pipe includes a pipe body and a plurality of nozzles, the nozzles are arranged along the pipe The circumferential intervals of the duct body are arranged into multiple rows, and each row of nozzles includes a number of nozzles arranged at intervals along the extension direction of the duct body. The duct body has a first section and a second section extending along the second direction and connected to each other, the first section and the second section are symmetrical about the center of the duct body, the free end of the first section has a first air inlet, the free end of the second section has a second air inlet, the cross-sectional area of ​​the first section gradually decreases in the direction away from the first air inlet, and the cross-sectional area of ​​the second section gradually decreases in the direction away from the second air inlet, the first direction and the second direction are both orthogonal to the up and down direction, and the first direction is orthogonal to the second direction.

[0011] The circulating fluidized bed in the embodiment of the present invention is provided with a first section and a second section, which improves the uniformity of the air distribution of the air distribution pipe, reduces the loss of air distribution uniformity, reduces the loss of a large number of fine particles, and can directly discharge large particles out of the furnace, preventing large particle materials from having an adverse effect on the fluidized combustion process in the furnace, thereby improving the efficiency of the fluidized combustion in the furnace.

[0012] In some embodiments, the outlets of the nozzles in the same row are located at the same height when viewed from the first direction.

[0013] In some embodiments, the plurality of air distribution ducts include: a plurality of first air distribution ducts, the plurality of first air distribution ducts are arranged in the chamber and extend along the second direction, the plurality of first air distribution ducts are spaced apart along the first direction to form a first discharge channel, and the first air distribution ducts are suitable for introducing hot primary air; a plurality of second air distribution ducts, the plurality of second air distribution ducts are arranged in the chamber and extend along the second direction, the plurality of second air distribution ducts are spaced apart and relatively arranged with the plurality of first air distribution ducts in the up and down directions, the plurality of second air distribution ducts are spaced apart along the first direction to form a second discharge channel, the first discharge channel and the second discharge channel are spaced apart and relatively arranged in the up and down directions, and the second air distribution ducts are suitable for introducing cold primary air.

[0014] In some embodiments, in a projection plane orthogonal to the first direction, the projection of the top of the first air distribution duct and the projection of the bottom of the second air distribution duct are both horizontal lines.

[0015] In some embodiments, the flow rate of the airflow ejected from the nozzle of the first air distribution duct adjacent to the inner wall of the furnace is 15m / s-43m / s, the flow rate of the airflow ejected from the nozzle of the first air distribution duct away from the inner wall of the furnace is 25m / s-100m / s, and the flow rate of the airflow ejected from the nozzle of the second air distribution duct is 20m / s-80m / s.

[0016] In some embodiments, the nozzle of the first air distribution duct is arranged adjacent to the top of the first air distribution duct, and the angle between the extension direction of the nozzle of the first air distribution duct and the up-down direction is 0°-150°; the nozzle of the second air distribution duct is arranged adjacent to the bottom of the second air distribution duct, and the angle between the extension direction of the nozzle of the second air distribution duct and the up-down direction is 0°-90°.

[0017] In some embodiments, in a projection plane orthogonal to the second direction, at least one of the first air distribution duct and the second air distribution duct includes a first arc segment, a first vertical segment, a second arc segment and a second vertical segment, and the first arc segment and the second arc segment are spaced relative to each other in the up and down directions, and the upper and lower ends of the first vertical segment are respectively connected to one end of the first arc segment and one end of the second arc segment, and the upper and lower ends of the second vertical segment are respectively connected to the other end of the first arc segment and the other end of the second arc segment.

[0018] In some embodiments, the circulating fluidized bed further comprises a plurality of heat exchange tubes, the plurality of heat exchange tubes extending along the second direction and being arranged in the chamber, the plurality of heat exchange tubes being located between the plurality of air distribution tubes and the discharge port, the plurality of heat exchange tubes forming a plurality of rows along the up and down directions, each row comprising a plurality of heat exchange tubes, the plurality of heat exchange tubes being spaced apart along the first direction to form a third discharge channel, the heat exchange tubes of one of the two adjacent rows of heat exchange tubes and the third discharge channels of the heat exchange tubes of the other of the two adjacent rows of heat exchange tubes being spaced apart and relative to each other in the up and down directions.

[0019] In some embodiments, the inner diameters of the first arc segment of the first air distribution pipe and the second arc segment of the first air distribution pipe are both in the range of 100mm-400mm, the inner diameters of the first arc segment of the second air distribution pipe and the second arc segment of the second air distribution pipe are both in the range of 76mm-350mm, the spacing between two adjacent first air distribution pipes and the spacing between two adjacent second air distribution pipes are both in the range of 76mm-350mm, and the spacing between the first air distribution pipe and its corresponding second air distribution pipe is in the range of 120mm-700mm.

[0020] In some embodiments, the chamber has a first cavity, a second cavity, and a third cavity that are connected in sequence in the up and down directions, the feed port is formed in the first cavity, the second cavity is constant in the up and down directions, a plurality of the air distribution pipes are formed in the second cavity, the cross-sectional area of ​​the third cavity gradually decreases in the direction away from the second cavity, the discharge port is formed at the bottom of the second cavity, and a plurality of the heat exchange tubes are arranged in the third cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of a circulating fluidized bed according to an embodiment of the present invention.

[0022] Figure 2 It is a cross-sectional view of the air distribution duct of the circulating fluidized bed according to the first embodiment of the present invention.

[0023] Figure 3 It is a cross-sectional view of the air distribution duct of the circulating fluidized bed according to the second embodiment of the present invention.

[0024] Figure 4 It is a cross-sectional view of the air distribution duct of the circulating fluidized bed according to the third embodiment of the present invention.

[0025] Figure 5 It is a schematic diagram of the assembly of heat exchange tubes of a circulating fluidized bed according to an embodiment of the present invention.

[0026] Figure 6 Schematic diagram of the positions of two adjacent rows of heat exchange tubes in a circulating fluidized bed according to an embodiment of the present invention.

[0027] Figure 7 yes Figure 1 A partial enlarged view of AA in .

[0028] Circulating fluidized bed 100;

[0029] Furnace 1; chamber 11; first chamber 111; second chamber 112; third chamber 113; feed port 12; discharge port 13;

[0030] Air distribution pipe 2; discharge channel 21; pipe body 22; nozzle 23; first air distribution pipe 24; second air distribution pipe 25; first arc segment 26; first vertical segment 27; second arc segment 28; second vertical segment 29;

[0031] Heat exchange tube 3; third discharge channel 31. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0033] A circulating fluidized bed according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0034] like Figure 1-7 As shown, the circulating fluidized bed 100 according to an embodiment of the present invention includes a furnace 1 and a plurality of air distribution pipes 2 .

[0035] The furnace 1 has a chamber 11, a feed port 12 and a discharge port 13. The feed port 12 and the discharge port 13 are both connected to the chamber 11. The discharge port 13 is provided at the bottom of the furnace 1 and is spaced apart from the feed port 12 in the vertical direction. Figure 1 As shown, the feed port 12 is provided on the side of the furnace 1 , and the material can flow into the furnace 1 through the feed port 12 . The discharge port 13 is formed at the bottom of the furnace 1 , and the burned slag and large particles in the material can flow out of the furnace 1 through the discharge port 13 .

[0036] A plurality of air distribution pipes 2 are arranged in the chamber 11 and are located between the feed port 12 and the discharge port 13. The plurality of air distribution pipes 2 are spaced apart along the first direction to form a discharge channel 21. At least a portion of the discharge channel 21 is arranged relative to the discharge port 13 in the up and down directions so that large particle materials can flow into the discharge port 13 through the discharge channel 21. The air distribution pipes 2 include a pipe body 22 and a plurality of nozzles 23. The nozzles 23 are spaced apart into multiple rows along the up and down directions. Each row includes a plurality of nozzles 23 spaced apart along the extension direction of the pipe body 22. The pipe body 22 has a first section and a second section extending along the second direction and connected to each other. The first section and the second section are symmetrical about the center of the pipe body 22. The free end of the first section has a first air inlet, and the free end of the second section has a second air inlet. The cross-sectional area of ​​the first section gradually decreases in the direction away from the first air inlet, and the cross-sectional area of ​​the second section gradually decreases in the direction away from the second air inlet. The first direction and the second direction are both orthogonal to the up and down direction, and the first direction is orthogonal to the second direction.

[0037] Specifically, if Figure 1As shown, the first direction is the left-right direction, the second direction is the front-to-back direction, the air distribution pipe 2 extends in the front-to-back direction, the air distribution pipe 2 is spaced apart in the left-to-right direction, and a material channel is formed between two adjacent air distribution pipes 2. The pipe body 22 includes a first section and a second section in the front-to-back direction. The lengths of the first section and the second section are equal, and the rear end of the first section is connected to the front end of the second section. The cross-sectional area of ​​the first section gradually decreases from front to back, and the cross-sectional area of ​​the second section gradually decreases from back to front. As a result, the cross-sectional area of ​​the pipe body 22 first decreases and then increases from front to back, thereby ensuring that the average flow velocity of the primary air flow through the air distribution pipe 2 is equal everywhere. The front end of one section is the first air inlet, and the rear end of the second section is the second air inlet. The primary air is delivered to the first air inlet and the second air inlet at the same time by the fan. In other words, the air distribution duct 2 adopts the air intake method on both sides of the front and back sides, and the middle section is the section with the smallest cross-section, which improves the high air distribution uniformity of the air distribution duct 2. The primary air is blown into the furnace 1 through the nozzle 23 to blow small particles into the furnace 1 for combustion. Large particles will flow into the discharge port 13 from the material channel due to their large weight, thereby realizing fluidized sorting of the material stored at the bottom of the furnace 1, retaining small particles that promote heat and mass transfer, and allowing large particles to fall into the filling hopper through the material channel.

[0038] The circulating fluidized bed 100 of the embodiment of the present invention is provided with a first section and a second section, which improves the uniformity of the air distribution of the air distribution pipe 2, reduces the loss of air distribution uniformity, and reduces the loss of a large number of fine particles. A material channel is provided to discharge large particles directly out of the furnace 1, preventing large particle materials from having an adverse effect on the fluidized combustion process in the furnace, thereby improving the efficiency of the fluidized combustion in the furnace 1.

[0039] It is worth noting that, compared with the design of making the cross-sectional area of ​​the inner circumference of the pipe body 22 gradually decrease from front to back, it is also possible to achieve basically the same flow rate control in the pipe body 22, but this setting is bound to make one end of the air distribution pipe 2 larger and the other end smaller, and according to experience, the load exerted by the coarse slag particles at the edge of the pipe is larger and smaller in the center. Therefore, a tapering and expanding design with thicker sides and thinner center is adopted, which not only ensures that the average flow rate of air flowing through the air distribution pipe 2 is equal everywhere, but also avoids uneven force and extends the service life of the air distribution pipe 2.

[0040] In some embodiments, multiple air distribution ducts 2 are arranged in a vertically spaced arrangement to form multiple rows, and each row of air distribution ducts 2 includes a plurality of air distribution ducts 2 spaced apart along a first direction. Specifically, the multiple rows of air distribution ducts 2 are equally spaced apart in the vertical direction, and the plurality of air distribution ducts 2 in each row are equally spaced apart in the left-right direction. The air distribution ducts 2 in the upper row and the air distribution ducts 2 in the lower row are spaced apart relative to each other in the vertical direction, and the air distribution ducts 2 in the lowermost row can be supplied with cold primary air, while the remaining air distribution ducts 2 can be supplied with hot primary air. The hot primary air introduced into the furnace 1 through the air distribution ducts 2 can blow the fine material fed into the furnace 1 into the furnace 1 for fluidization.

[0041] In some embodiments, in a projection plane orthogonal to the second direction, the air distribution pipes 2 are symmetrically arranged about the vertical direction, and the outlets of the nozzles 23 in the same row are located at the same height when viewed from the first direction. Figure 2-4 As shown, the left half of the air distribution duct 2 and the right half of the air distribution duct 2 are symmetrical along the left-right direction, and the nozzles 23 located in the left half of the air distribution duct 2 and the nozzles 23 located in the right half of the air distribution duct 2 are symmetrical about the left-right direction, and the nozzles 23 in the same row are located at the same height in the front-to-back direction, thereby further ensuring uniform air distribution.

[0042] In some embodiments, in the projection plane orthogonal to the second direction, the outlets of the nozzles 23 on the same side of the air distribution pipe 2 are located on the same vertical line. Figure 3 As shown, the nozzles 23 located in the left half of the air distribution duct 2 are located on the same vertical line, and the nozzles 23 located in the right half of the air distribution duct 2 are located on the same vertical line. Compared with the uneven setting of the nozzles 23, the additional resistance caused by the falling of large particles is avoided, so that the large particles can flow out smoothly in the material channel.

[0043] In some embodiments, the plurality of air distribution ducts 2 include a plurality of first air distribution ducts 24 and a plurality of second air distribution ducts 25 .

[0044] A plurality of first air distribution pipes 24 are provided in the chamber 11 and extend along the second direction. The plurality of first air distribution pipes 24 are spaced apart along the first direction to form a first discharge channel. A plurality of second air distribution pipes 25 are provided in the chamber 11 and extend along the second direction. The plurality of second air distribution pipes 25 are spaced apart and arranged opposite to the plurality of first air distribution pipes 24 in the vertical direction. The plurality of second air distribution pipes 25 are spaced apart and arranged opposite to each other in the first direction to form a second discharge channel. The first discharge channel and the second discharge channel are spaced apart and arranged opposite to each other in the vertical direction. Specifically, Figure 2-4As shown, the first air distribution pipe 24 is arranged above the second air distribution pipe 25, the first air distribution pipe 24 is arranged at intervals in the left-right direction, the first discharge channel is formed between the two adjacent first air distribution pipes 24, the second air distribution pipe 25 is arranged at intervals in the left-right direction, the second discharge channel is formed between the two adjacent second air distribution pipes 25, and the first discharge channel and the second discharge channel are arranged relative to each other in the up-down direction, so that the large particle material flows out of the discharge port 13 through the first discharge channel and the second discharge channel in sequence, and the first air distribution pipe 24 can be introduced into the hot primary air, so that the hot primary air is blown into the furnace 1 to blow up and fluidize the material in the furnace 1, and the introduction of the hot primary air can also prevent the temperature of the furnace 1 from decreasing, thereby To ensure the normal operation of the furnace 1, the second air distribution duct 25 can be introduced into the cold primary air, so that the cold primary air can exchange heat with the large particle material so that the large particle material heats the cold primary air, which not only recovers the heat energy of the large particle material, but also saves the operating cost of the cold primary air entering the preheater for preheating. Therefore, the first air distribution duct 24 and the second air distribution duct 25 adopt an upper and lower two-layer design. The first air distribution duct 24 introduces hot primary air to provide good initial fluidization conditions, and the second air distribution duct 25 introduces cold primary air. The cold primary air undergoes a relatively strong convective heat exchange with the falling coarse particles during the rising process, and the temperature increases and the air velocity increases, thereby replenishing the hot primary air volume and effectively cooling the coarse particles at the same time.

[0045] In some embodiments, the velocity of the airflow ejected from the nozzle 23 of the first air distribution duct 24 adjacent to the inner wall of the furnace 1 is 15 m / s-43 m / s, the velocity of the airflow ejected from the nozzle 23 of the first air distribution duct 24 distal to the inner wall of the furnace 1 is 25 m / s-100 m / s, and the velocity of the airflow ejected from the nozzle 23 of the second air distribution duct 25 is 20 m / s-80 m / s. Specifically, by adjusting the power of the fan, the air velocity (v1) in the tube row near the wall of the first air distribution duct 24 is selected within the range of [15, 43] m / s, the air velocity (v2) in the tube row not near the wall of the first air distribution duct 24 is selected within the range of [25, 100] m / s, and the air velocity (v3) in the second air distribution duct 25 is selected within the range of [20, 80] m / s. As a result, the air flow velocity on the wall of the furnace 1 is smaller, thereby weakening the influence of the side wall effect in the furnace 1 and preventing the air from concentrating or flowing toward the side wall due to the side wall effect. The air flow velocity of the first air distribution duct 24 and the second air distribution duct 25 cannot be too large, otherwise it will easily lead to the side wall effect. The air flow velocity of the first air distribution duct 24 and the second air distribution duct 25 cannot be too small, otherwise it will cause the air flow to fail to blow up the material, thereby causing the material to accumulate in the furnace 1, affecting the fluidization efficiency of the circulating fluidized bed 100.

[0046] In some embodiments, the nozzle 23 of the first air distribution pipe 24 is disposed adjacent to the top of the first air distribution pipe 24, and the angle between the extending direction of the nozzle 23 of the first air distribution pipe 24 and the vertical direction is 0°-105°. Figure 2-4 As shown, the nozzle 23 of the first air distribution duct 24 is located at the upper portion of the first air distribution duct 24. The angle between the extension direction of the nozzle 23 of the first air distribution duct 24 and the vertical direction is α1. The jet angle of the nozzle 23 cannot be too large (α1 <= 105°). A too large angle may cause certain large-sized particles to flow along the nozzle 23 and block the nozzle opening. Because a certain horizontal component is required to sweep and separate fine particles, the jet angle of the nozzle 23 cannot be completely downward (α1 > 0°). Therefore, α1 is set to 0°-105°, making the jet angle setting of the nozzle 23 of the first air distribution duct 24 more reasonable.

[0047] In some embodiments, the nozzle 23 of the second air distribution pipe 25 needs to have a horizontal or downward jet angle to prevent coarse particles with a certain speed from falling and colliding, which may cause wear on the nozzle 23. At the same time, the primary air can also sweep the coarse particles before entering the furnace 1, thereby further preheating them. Therefore, in some embodiments, the nozzle 23 of the second air distribution pipe 25 is arranged near the bottom of the second air distribution pipe 25, and the angle between the extension direction of the nozzle 23 of the second air distribution pipe 25 and the vertical direction is 0°-90°. Specifically, as Figure 2-4 As shown, the nozzle 23 of the second air distribution duct 25 is arranged at the lower part of the second air distribution duct 25, and the angle between the extension direction of the nozzle 23 of the second air distribution duct 25 and the up and down direction is α2, and the value range of α2 is 0°, 30°, 60°, etc., so that the setting of α2 is more reasonable.

[0048] In some embodiments, in a projection plane orthogonal to the first direction, the projection of the top of the first air distribution pipe 24 and the projection of the bottom of the second air distribution pipe 25 are both horizontal lines. Figure 2-4 As shown, the cross-sectional area of ​​the inner circumference of the first air distribution duct 24 is first reduced to the same size from front to back with its top as the reference. In other words, the first air distribution duct 24 is scaled around its upper end face, and the cross-sectional area of ​​the inner circumference of the second air distribution duct 25 is first reduced to the same size from front to back with its bottom as the reference. In other words, the second air distribution duct 25 is scaled around its lower end face, thereby improving the uniformity of air distribution. Taking the second air distribution duct 25 as an example, its design principle is explained in detail. The nozzle 23 of the second air distribution duct 25 is arranged downward, and it is necessary to ensure that the nozzle 23 of the second air distribution duct 25 is at the same height. Therefore, the scaling of the second air distribution duct 25 around the lower end face can more conveniently set the nozzle 23 without lengthening or shortening the nozzle 23 of the second air distribution duct 25, thereby reducing the processing and manufacturing costs of the first air distribution duct 24 and the second air distribution duct 25.

[0049] In some embodiments, within the projection plane orthogonal to the second direction, the air distribution duct 2 includes a first arc segment 26, a first vertical segment 27, a second arc segment 28 and a second vertical segment 29. The first arc segment 26 and the second arc segment 28 are spaced apart and relatively arranged in the up and down directions. The upper and lower ends of the first vertical segment 27 are respectively connected to one end of the first arc segment 26 and one end of the second arc segment 28. The upper and lower ends of the second vertical segment 29 are respectively connected to the other end of the first arc segment 26 and the other end of the second arc segment 28.

[0050] Specifically, if Figure 2 As shown, the projection surfaces of the first air distribution duct 24 and the second air distribution duct 25 are both in the shape of a circular runway, the first arc segment 26 and the second arc segment 28 are both arc-shaped, the left end of the first arc segment 26 is connected to the upper end of the first vertical segment 27, the right end of the first arc segment 26 is connected to the upper end of the second vertical segment 29, the left end of the second arc segment 28 is connected to the lower end of the first vertical plate, and the right end of the second arc segment 28 is connected to the lower end of the second vertical segment 29. Therefore, according to the experimental research results of the inventor on pipeline wear, experiments and simulations show that the use of this special-shaped tube can reduce pipeline wear, extend the service life of the first air distribution duct 24 and the second air distribution duct 25, and also increase the air circulation area in the first air distribution duct 24 and the second air distribution duct 25, thereby improving the air distribution effect of the first air distribution duct 24 and the second air distribution duct 25.

[0051] In some embodiments, as Figure 4 As shown, in the projection plane orthogonal to the second direction, the projection of the air distribution duct 2 can be circular, thereby reducing the processing and manufacturing cost of the air distribution duct 2.

[0052] In some embodiments, the inner diameter of the first arc segment 26 and the inner diameter of the second arc segment 28 of the first air distribution duct 24 are both in the range of 100 mm to 400 mm, and the inner diameter of the first arc segment 26 and the inner diameter of the second arc segment 28 of the second air distribution duct 25 are both in the range of 76 mm to 350 mm. Figure 2-4As shown, the diameter of the first arc segment 26 of the first air distribution pipe 24 and the diameter of the second arc segment 28 of the first air distribution pipe 24 are both D1 and the range is [100,400] mm. The diameter of the first arc segment 26 of the second air distribution pipe 25 and the diameter of the second arc segment 28 of the second air distribution pipe 25 are both D2 and the range is [76,350] mm. If the diameters of the first air distribution pipe 24 and the second air distribution pipe 25 are too large, the first air distribution pipe 24 and the second air distribution pipe 25 will occupy The larger the air distribution area used, the fewer the number of rows of the first air distribution duct 24 and the second air distribution duct 25, the greater the possibility of uneven air distribution, the diameters of the first air distribution duct 24 and the second air distribution duct 25 are too small, the more rows of the first air distribution duct 24 and the second air distribution duct 25, the weaker the load-bearing capacity of a single pipe of the first air distribution duct 24 and the second air distribution duct 25, and the higher the operating cost. Since the first air distribution duct 24 mainly bears the load in the upper row, the diameter of the first air distribution duct 24 is larger than that of the second air distribution duct 25.

[0053] In some embodiments, the range of the spacing between two adjacent first air distribution pipes 24 and the range of the spacing between two adjacent second air distribution pipes 25 are both 76 mm to 350 mm. Specifically, Figure 2-4 As shown, the spacing between two adjacent first air distribution pipes 24 and the spacing between two adjacent second air distribution pipes 25 are both S1 selected in the range of [76,350] mm. In other words, the size of the first discharge channel in the left and right directions and the size of the second discharge channel in the left and right directions are both S1 selected in the range of [76,350] mm, thereby ensuring that the first discharge channel and the second discharge channel do not leak fine materials while also not leaving coarse materials, thereby making the setting of the first air distribution pipe 24 and the second air distribution pipe 25 more reasonable.

[0054] In some embodiments, the distance between the first air distribution pipe 24 and the corresponding second air distribution pipe 25 ranges from 120 mm to 700 mm. Figure 2-4 As shown, the spacing between the first air distribution duct 24 and the second air distribution duct 25 in the upper and lower directions is S2, and the selection range is [120,720] mm. When the spacing is too large, the air distribution area occupied by the first air distribution duct 24 and the second air distribution duct 25 will be larger, resulting in the size of the furnace 1 being too large. When the spacing is too small, the installation space for the first air distribution duct 24 and the second air distribution duct 25 is small, which will increase the difficulty of installing and manufacturing the first air distribution duct 24 and the second air distribution duct 25.

[0055] In some embodiments, the circulating fluidized bed 100 further includes a plurality of heat exchange tubes 3, the plurality of heat exchange tubes 3 extending along the second direction and arranged in the chamber 11, the plurality of heat exchange tubes 3 being located between the plurality of air distribution tubes 2 and the discharge port 13, the plurality of heat exchange tubes 3 forming a plurality of rows along the vertical direction, each row including a plurality of heat exchange tubes 3, the plurality of heat exchange tubes 3 being spaced apart along the first direction to form a third discharge channel 31, the heat exchange tubes 3 of one of the two adjacent rows of heat exchange tubes 3 and the third discharge channel 31 of the other of the two adjacent rows of heat exchange tubes 3 being spaced apart and arranged relative to each other in the vertical direction. Specifically, as Figure 5-6 As shown, the heat exchange tubes 3 extend in the front-to-back direction and are suitable for passing normal temperature unsalted water. The heat exchange tubes 3 are arranged in the chamber 11 and are located above the discharge port 13 below the second air distribution duct 25. When large particles flow into the third discharge channel 31 between the heat exchange tubes 3, the large particles can exchange heat with the heat exchange tubes 3, allowing the large particles to heat the unsalted water through the heat pipes, thereby effectively utilizing the thermal energy of the large particles. In addition, the third discharge channel 31 between the upper row of heat exchange tubes 3 and the adjacent lower row of heat exchange tubes 3 is arranged relative to each other in the vertical direction. As a result, the heat exchange tubes 3 are arranged in a staggered manner, and the heat exchange flow between the unsalted water and the large particles is downstream, thereby increasing the contact between the large particles and the tube wall of the heat exchange tubes 3, thereby improving the heat exchange efficiency.

[0056] In some embodiments, in order to address the large demand for heat exchange surface and high cost of the subsequent coarse particle waste heat recovery device, it is considered to design the filling hopper as a mobile packed bed heat exchanger, and pre-cool the slag by setting up water-cooled walls, buried pipes or blowing gap air, so as to further recover the waste heat of the slag.

[0057] In some embodiments, the circulating fluidized bed 100 also includes a slag discharge valve, which is a battery valve located at the discharge port 13. The slag discharge valve can be used to switch between continuous slag discharge and intermittent slag discharge. At the same time, the residence time of high-temperature slag in the moving packed bed can also be controlled to achieve controllable particle-working fluid heat exchange on the moving bed.

[0058] In some embodiments, the chamber 11 has a first chamber 111, a second chamber 112 and a third chamber 113 that are connected in sequence in the up and down directions. The feed port 12 is formed in the first chamber 111. The second chamber 112 is constant in the up and down directions. A plurality of air distribution pipes 2 are formed in the second chamber 112. The cross-sectional area of ​​the third chamber 113 gradually decreases in the direction away from the second chamber 112. The discharge port 13 is formed at the bottom of the second chamber 112, and a plurality of heat exchange tubes 3 are arranged in the third chamber 113.

[0059] Specifically, if Figure 1As shown, the first chamber 111 is located above the second chamber 112, and the third chamber 113 is located above the second chamber 112. The first chamber 111 is a combustion chamber, the second chamber 112 is a fluidizing chamber, and the third chamber 113 is a heat exchange chamber. The feed port 12 is formed on the side of the first chamber 111 and is connected to the first chamber 111. The first air distribution pipe 24 and the second air distribution pipe 25 are both arranged in the second chamber 112. The cross-sectional area of ​​the third chamber 113 gradually decreases from top to bottom. The discharge port 13 is formed at the bottom of the third chamber 113 and the heat exchange pipe 3 is arranged in the third chamber 113. Therefore, it is convenient for the material to flow into the third chamber 113 and out through the third chamber 113, making the setting of the chamber 11 more reasonable.

[0060] In some embodiments, in a projection plane orthogonal to the first direction, the angle between the projection of the outer peripheral surface of the third cavity 113 and the horizontal line is in a range of 55°-75°, and in a projection plane orthogonal to the second direction, the angle between the projection of the outer peripheral surface of the third cavity 113 and the horizontal line is in a range of 60°-78°. Specifically, Figure 1 and Figure 7 As shown, α3 is 55°-75°, and α4 is 60°-78°. Thus, the shape of the outlet is determined by the inclination angle, which facilitates the processing and manufacturing of the discharge port 13 and makes the setting of the discharge port 13 more reasonable.

[0061] In summary, compared with the prior art, the present invention has the following advantages and outstanding technical effects: 1. The first air distribution pipe 24 and the second air distribution pipe 25 are arranged in the present invention to realize the effective fluidization sorting of wide-particle slag, discharge coarse particles while retaining fine particles, and is suitable for processing wide-particle-size distribution slag and large-particle slag (coarse particles have larger particle sizes and belong to the category of particles that are more difficult to fluidize. The drag force they receive is smaller than gravity, so their movement form is downward sedimentation, and then they can continuously pass through the tube gap; the opposite is true for fine particles); 2. The use of evenly arranged tubular air distribution can further improve the air distribution uniformity, thereby improving the fluidization quality at the bottom of the furnace 1 (in the past, air distribution plates were mostly used). The bottom material is transported to the slag discharge port in a directional manner by tilting or installing a directional hood on the air distribution plate, and the slag discharge port is set on the air distribution plate, occupying the air distribution area, which inevitably leads to a certain degree of air distribution unevenness); 3. By arranging a certain number of heat pipes in the filling hopper to pre-recover the waste heat of slag discharge (for example: large particle materials), pre-cooling of the slag before it is discharged from the furnace is achieved, strengthening the waste heat recovery of the slag, and reducing the subsequent waste heat recovery investment (recovering higher-grade heat energy in advance, reducing heat dissipation losses, and reducing the subsequent heat exchange area requirements). 4. Only the air distribution and slag discharge structures of the original furnace are modified, which is suitable for handling slag discharge with a wide particle size distribution and large particle size slag discharge, with flexible design and convenient implementation.

[0062] The structure of the circulating fluidized bed 100 according to the embodiment of the present invention is described in detail below.

[0063] Example 1: Using Figure 1-2 The tubular air distribution system shown in the figure realizes continuous slag discharge of 100 large particles in a circulating fluidized bed, and its design parameters are as follows: the air flow rate v1 in the near-wall tube row of the first air distribution tube 24 is 20 m / s, and the air flow rate v2 in the non-near-wall tube row of the first air distribution tube 24 is 50 m / s; the air flow rate v3 in the tube row of the second air distribution tube 25 is 20 m / s, the diameter D1 of the arc section of the first air distribution tube 24 is 200 mm, the diameter D2 of the arc section of the second air distribution tube 25 is 76 mm, the length L1 of the first vertical section 27 and the second vertical section 29 of the arc of the first air distribution tube 24 are both 100 mm, the length L2 of the first vertical section 27 and the second vertical section 29 of the arc of the second air distribution tube 25 are both 38 mm, the horizontal tube row spacing S1 is 76 mm, the vertical tube row spacing S2 is 120 mm, and the nozzle 23 spacing S3 of the first air distribution tube 24 is 80mm, the nozzle 23 spacing S4 of the second air distribution duct 25 is 80mm, the nozzle 23 outlet diameter D3 is 20mm, the nozzle 23 jet angle α1 of the first air distribution duct 24 is 90°, and the nozzle 23 jet angle α2 of the second air distribution duct 25 is 90°. In the projection plane orthogonal to the front-to-back direction, the number of nozzles 23 of the first air distribution duct 24 is 2, and the number of nozzles 23 of the second air distribution duct 25 is 1. The air distribution area W1×H1×Dt1 is 1800×9000×600mm, the filling hopper outlet W2×Dt2 is 414×7614mm, the filling area hopper height H2 is 1200mm, the filling hopper inclination angles α3 and α4 are both 60°, the diameter D4 of the heat exchange tube 3 is 57mm, the spacing S5 of the heat exchange tube 3 is 250mm, and the vertical tube spacing S6 of the heat exchange tube 3 is 250mm.

[0064] Example 2: Using Figure 1 and Figure 4 The tubular air distribution system shown in FIG1 is used to realize continuous slag discharge of 100 large particles in a circulating fluidized bed. Figure 2 The shown air distribution duct 2-tube type design replaces the original design, and its design parameters are: the diameter D1 of the first air distribution duct 24 is 200 mm, the diameter D2 of the second air distribution duct 25 is 76 mm, the horizontal tube row spacing S1 is 76 mm, the vertical tube row spacing S2 is 120 mm, the nozzle 23 spacing S3 of the first air distribution duct 24 is 80 mm, the nozzle 23 spacing S4 of the second air distribution duct 25 is 80 mm, the nozzle 23 outlet diameter D3 is 20 mm, the jet angle α1 of the nozzle 23 of the first air distribution duct 24 is 90°, the jet angle α2 of the nozzle 23 of the second air distribution duct 25 is 90°, and in the projection plane orthogonal to the front-to-back direction, the number of nozzles 23 of the first air distribution duct 24 is 2, and the number of nozzles 23 of the second air distribution duct 25 is 1.

[0065] Example 3: Using Figure 1The tubular air distribution system shown in FIG1 is used to realize continuous slag discharge of 100 large particles in a circulating fluidized bed. Figure 3 The nozzle 23 design shown replaces the original design, and its design parameters are as follows: the diameters of the first arc segment 26 and the second arc segment 28 of the first air distribution duct 24 are both 200 mm, the diameters of the first arc segment 26 and the second arc segment 28 of the second air distribution duct 25 are both 76 mm, the lengths of the first vertical segment 27 and the second vertical segment 29 of the first air distribution duct 24 are both 100 mm, the lengths of the first vertical segment 27 and the second vertical segment 29 of the second air distribution duct 25 are both 38 mm, the horizontal tube row spacing S1 is 76 mm, and the vertical tube row spacing S 2 is 120mm, the spacing S3 between the nozzles 23 of the first air distribution duct 24 is 80mm, the spacing S4 between the nozzles 23 of the second air distribution duct 25 is 80mm, the outlet diameter D3 of the nozzle 23 is 20mm, and in the projection plane orthogonal to the front-to-back direction, the first air distribution duct 24 has 3 pairs of nozzles 23, and the jet angles are 90°, 45° and 90° respectively, the second air distribution duct 25 has 2 pairs of nozzles 23, and the flow angles are 0° and 90° respectively, the number of nozzles 23 of the first air distribution duct 24 is 6, the number of nozzles 23 of the second air distribution duct 25 is 3, and the nozzles 23 are evenly distributed.

[0066] Example 4: Using Figure 1 The tubular air distribution system shown in FIG1 is used to realize continuous slag discharge of 100 large particles in a circulating fluidized bed. Figure 5 The waste heat pre-recovery scheme shown replaces the original design, and its design parameters are: the gap air blowing position is the middle section of the side, and the total gap air blowing flow is 1 / 10 of the total cold primary air volume.

[0067] The modification scheme of this embodiment is to blow a certain flow of interstitial cold air into the middle section of the side of the filling lower hopper as auxiliary air, thereby weakening the thickness of the thermal boundary layer, unblocking the particle bridges, and enhancing heat exchange; at the same time, the interstitial cold air absorbs the waste heat of the coarse particles and can be further used as auxiliary hot primary air to be introduced into the furnace 1.

[0068] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0070] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0071] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0072] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0073] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A circulating fluidized bed, characterized in that: include: A furnace, the furnace having a chamber, a feed port and a discharge port, the feed port and the discharge port both being in communication with the chamber, the discharge port being provided at the bottom of the furnace and spaced apart from the feed port in the vertical direction; 18. The smoke screen of claim 17, wherein the smoke screen is located adjacent to the intake manifold and adjacent to the intake manifold, wherein the smoke screen is located adjacent to the intake manifold. The plurality of air distribution ducts include: a plurality of first air distribution pipes, the plurality of first air distribution pipes being disposed in the chamber and extending along the second direction, the plurality of first air distribution pipes being spaced apart along the first direction to form a first discharge channel, the first air distribution pipes being adapted to introduce hot primary air; Multiple second air distribution ducts are arranged in the chamber and extend along the second direction. Multiple second air distribution ducts and multiple first air distribution ducts are arranged one by one relative to each other in the up and down directions. Multiple second air distribution ducts are arranged at intervals along the first direction to form a second discharge channel. The first discharge channel and the second discharge channel are arranged at intervals relative to each other in the up and down directions. The second air distribution ducts are suitable for introducing cold primary air.

2. The circulating fluidized bed according to claim 1, characterized in that Viewed from the first direction, the outlets of the nozzles in the same row are located at the same height.

3. The circulating fluidized bed according to claim 1, characterized in that In a projection plane orthogonal to the first direction, a projection of the top of the first air distribution duct and a projection of the bottom of the second air distribution duct are both horizontal lines.

4. The circulating fluidized bed according to claim 1, characterized in that The flow rate of the air flow ejected from the nozzle of the first air distribution duct adjacent to the inner wall of the furnace is 15m / s-43m / s, the flow rate of the air flow ejected from the nozzle of the first air distribution duct away from the inner wall of the furnace is 25m / s-100m / s, and the flow rate of the air flow ejected from the nozzle of the second air distribution duct is 20m / s-80m / s.

5. The circulating fluidized bed according to claim 1, characterized in that The nozzle of the first air distribution pipe is arranged near the top of the first air distribution pipe, and the angle between the extending direction of the nozzle of the first air distribution pipe and the up-down direction is 0°-150°. The nozzle of the second air distribution duct is arranged adjacent to the bottom of the second air distribution duct, and the angle between the extension direction of the nozzle of the second air distribution duct and the up-down direction is 0°-90°.

6. The circulating fluidized bed according to claim 1, characterized in that In the projection plane orthogonal to the second direction, at least one of the first air distribution duct and the second air distribution duct includes a first arc segment, a first vertical segment, a second arc segment and a second vertical segment. The first arc segment and the second arc segment are arranged relative to each other in the up and down directions. The upper and lower ends of the first vertical segment are respectively connected to one end of the first arc segment and one end of the second arc segment, and the upper and lower ends of the second vertical segment are respectively connected to the other end of the first arc segment and the other end of the second arc segment.

7. The circulating fluidized bed according to claim 6, characterized in that The inner diameter range of the first arc segment of the first air distribution pipe and the inner diameter range of the second arc segment of the second air distribution pipe are both 100mm-400mm, the inner diameter range of the first arc segment of the second air distribution pipe and the inner diameter range of the second arc segment of the second air distribution pipe are both 76mm-350mm, the distance between two adjacent first air distribution pipes and the distance between two adjacent second air distribution pipes are both in the range of 76mm-350mm, and the distance between the first air distribution pipe and its corresponding second air distribution pipe is in the range of 120mm-700mm.

8. The circulating fluidized bed according to any one of claims 1 to 6, characterized in that The heat exchange tubes further include a plurality of heat exchange tubes, the plurality of heat exchange tubes extending along the second direction and arranged in the chamber, the plurality of heat exchange tubes being located between the plurality of air distribution tubes and the discharge port, the plurality of heat exchange tubes forming a plurality of rows along the vertical direction, each row including a plurality of heat exchange tubes, and the plurality of heat exchange tubes being spaced apart along the first direction to form a third discharge channel. The heat exchange tubes in one row of the two adjacent rows of heat exchange tubes and the third discharge channels of the heat exchange tubes in the other row of the two adjacent rows of heat exchange tubes are arranged opposite to each other in an up-down direction.

9. The circulating fluidized bed according to claim 8, characterized in that The chamber has a first chamber, a second chamber and a third chamber that are connected in sequence in the up and down directions. The feed port is formed in the first chamber. The second chamber is constant in the up and down directions. Multiple air distribution pipes are formed in the second chamber. The cross-sectional area of ​​the third chamber gradually decreases in the direction away from the second chamber. The discharge port is formed at the bottom of the second chamber. Multiple heat exchange tubes are arranged in the third chamber.

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