CN112146087A

CN112146087A - Separator for circulating fluidized bed heat exchanger

Info

Publication number: CN112146087A
Application number: CN202010983157.6A
Authority: CN
Inventors: 彭超
Original assignee: Beijing Shengyin Energy Saving Technology Co ltd
Current assignee: Beijing Shengyin Energy Saving Technology Co ltd
Priority date: 2020-09-17
Filing date: 2020-09-17
Publication date: 2020-12-29
Anticipated expiration: 2040-09-17
Also published as: CN112146087B

Abstract

The invention relates to a separator for a circulating fluidized bed heat exchanger, comprising at least one cyclone unit, which comprises a housing; the shell is communicated with a fluid outlet to be separated of the circulating fluidized bed heat exchanger through a fluid pipe to be separated so as to supply the fluid to be separated containing externally introduced particles and fine scale pieces into the shell; the shell comprises at least one section of cylindrical section; the cyclone unit comprises cyclone blades coaxially arranged with the cylindrical section of the shell, and the cyclone blades are used for inducing cyclone of the fluid to be separated; the swirl blades occupy the whole cross section of the space in which they are located, so that all the fluid to be separated passing through the swirl blades is forced to generate swirl; the cyclone unit further comprises a liquid outlet pipe extending to the cylindrical section of the housing; at least the inlet section of the liquid outlet pipe and the cylindrical section of the shell are coaxially arranged, and the liquid outlet pipe is used for leading out a main body flow of the fluid to be separated after the exogenous particles are separated; the bottom of the shell is provided with a slag discharge port for discharging externally-introduced particles.

Description

Separator for circulating fluidized bed heat exchanger

Technical Field

The invention relates to the field of solid-liquid separation, in particular to a separator for a circulating fluidized bed heat exchanger.

Background

Heat transfer, as one of the operations of a three-pass-one-reverse and chemical engineering unit, occupies an important place throughout the chemical industry, even the general industry. The actual manifestation of heat transfer processes in the industry is mainly heat exchangers, such as plate, tube and tube exchangers, etc. Under the normal condition, cold and hot fluids participating in heat exchange need to be correspondingly treated so as to reduce the possibility of scaling in the heat exchanger, and further ensure that the heat exchange efficiency of the heat exchanger can be kept stable for a long time. However, in some cases, heat exchange with the fouling prone material is necessary, such as heating of the concentrated crystallization feed.

The circulating fluidized bed heat exchanger is equipment developed aiming at the heat exchange process of materials easy to scale, and the particles enter the heat exchanger along with material flow by introducing externally introduced particles and are fluidized in the heat exchanger, so that the heat exchange surface is continuously impacted and rubbed, and the scale formation on the surface of the heat exchanger is avoided. And then separating the externally introduced particles from the material flow by using solid-liquid separation equipment, and sending the separated externally introduced particles into the circulating fluidized bed heat exchanger again to realize the cyclic utilization of the externally introduced particles. Currently, the separators used in circulating fluidized bed heat exchanger systems are primarily single tangential inlet cyclone separators, wherein the fluid to be separated is introduced from the tangential inlet of the separator, thereby creating a cyclone and further separating the externally introduced particles from the fluid.

However, in the practical use process, the cyclone range of the single tangential inlet cyclone separator cannot cover the peripheral wall of the whole separator, and a cyclone dead zone exists in the separator, so that after long-term operation, a thicker scale layer can be formed on the side wall of the separator corresponding to the cyclone dead zone, the scale layer is easy to partially fall off under the impact and disturbance of cyclone fluid, and the fallen large scale pieces can be recycled into the heat exchanger and block the inlet at the lower part of the heat exchange tube, so that the heat exchange performance of the heat exchanger is rapidly reduced; in addition, the operation pressure drop of the single tangential inlet cyclone separator is large, so that the overall equipment height of the circulating fluidized bed heat exchanger is difficult to reduce, and the maximum inlet flow velocity of the cyclone is limited by the excessive operation pressure drop, so that the equipment size of the circulating fluidized bed heat exchanger is difficult to realize miniaturization; such a single tangential inlet cyclone also restricts the miniaturization modification of the equipment size at another angle, that is, when the diameter of the cyclone is reduced to a certain extent (usually 500mm), the externally introduced particles in the fluid and the fine scale flakes peeled off when impacting the inner wall of the heat exchange tube are simultaneously separated from the fluid, so that the externally introduced particles obtained by separation are contaminated by the fine scale flakes; the separated externally introduced particles and the small scale pieces enter a dipleg in the fluidized bed heat exchanger together, and due to the existence of the small particles, bridging is easily caused in the dipleg, so that the flow of the particles is interrupted, and the particles are lacked in the heat exchange tube, so that scaling in the heat exchange tube is caused; therefore, it is an urgent problem in the art to provide a separator capable of preventing the clogging of the circulating fluidized bed heat exchanger and the bridging of the dipleg and allowing the miniaturization of the equipment.

Disclosure of Invention

To solve the above problems in the prior art, the present invention provides a separator for a circulating fluidized bed heat exchanger. The separator can effectively inhibit the blocking phenomenon of the circulating fluidized bed heat exchanger, realize the long-term stable operation of heat exchange equipment, and allow the miniaturization transformation of the circulating fluidized bed heat exchanger.

Specifically, a separator is provided, and comprises at least one cyclone unit, wherein the cyclone unit comprises a shell, a liquid inlet, a liquid outlet pipe and a slag discharge port; the shell comprises at least one section of cylindrical section (the cylindrical section of the invention refers to that one section of the inner wall of the shell is a cylindrical peripheral wall, and the external form of the shell is not limited, for example, the shell can be a polygonal column structure with a cylindrical inner cavity); the cylindrical section is used for providing rotational flow constraint for fluid to be separated; the liquid inlet is arranged at the cylindrical section of the housing and provides an outlet for the fluid to be separated to enter the cylindrical section of the cyclone unit.

Preferably, the liquid inlet may be a tangential inlet, and it comprises at least three tangentially arranged on the cylindrical section side wall, and the at least three tangential inlets are arranged at the same height. The at least three tangential inlets can provide a cyclone range completely covering the inner wall of the separator, so that the inner wall of the whole separator is rubbed by using externally introduced particles in the fluid, the inner wall of the separator is prevented from scaling, and the problem that a heat exchanger is blocked due to peeling of large scale pieces caused by scaling of the inner wall of the separator is solved.

Alternatively, the inlet port may be a non-tangential inlet, which may be an end opening of a cylindrical section of the housing, whereby the non-tangential inlet may be allowed to have a diameter less than or equal to the diameter of the cylindrical section; alternatively, the non-tangential inlet may be an opening of a liquid inlet pipe extending into the cylindrical section, for example from the end of the housing, in the direction of the axis of the cylindrical section, or an opening of a liquid inlet pipe arranged non-tangentially on the side wall of the cylindrical section.

The swirl unit further comprises swirl vanes cooperating with the non-tangential inlet and adapted to induce swirl; the cyclone blade comprises a center shaft with a circular cross section and a plurality of fan blades uniformly fixed on the outer side of the center shaft, the outer edge (the side far away from the center shaft) of each fan blade limits the outer circle diameter dd of the cyclone blade, the center shaft limits the root circle diameter dx of the cyclone blade, and dd/dx is less than or equal to 4 so as to provide clear division of externally introduced particles and small scale pieces (the separator only separates the externally introduced particles without separating the small scale pieces, and particularly the content of the small scale pieces in the externally introduced particles after separation is lower than 2% wt). On the premise of satisfying the clear division of the externally introduced particles and the fine scale pieces, the swirl vane provided by the invention is allowed to have the minimum outer circle diameter of 50 mm.

The middle shaft is arranged to be coaxial with the cylindrical section of the shell, and the parts of the middle shaft, which are positioned at two sides of the fan blades, can be separately or respectively connected with guide cones, wherein the guide cones comprise an upstream cone and/or a downstream cone which can be optionally arranged. The swirl vanes may be provided in the housing or in the inlet duct.

The outlet pipe is configured to extend into the cylindrical section of the housing and at least its inlet section (referring to the initial section of fluid in the housing entering the outlet pipe) is arranged coaxially with the cylindrical section of the housing; the inlet section may have openings only at the end of the pipe, or the inlet section may have a plurality of meshes provided at the end of the pipe and the wall of the pipe, the mesh having a size smaller than that of the externally introduced pellets, to draw the fluid from the middle of the cylindrical section after separating the externally introduced pellets; the inlet section of the outlet pipe has an inner diameter D, and the housing at the height of the opening of the inlet section of the outlet pipe has an inner diameter D. Wherein D/D is less than or equal to 0.8, so as to provide sufficient clearance for separating the externally introduced particles from the material flow while ensuring the treatment capacity.

The slag discharge port is in fluid communication with an inner cavity of the shell outside the inlet section of the liquid outlet pipe and provides a passage for separated externally-introduced particles to leave the cyclone unit.

The cyclone unit can be used as a separator independently, for example, a liquid inlet of the cyclone unit is directly communicated with a fluid pipe to be separated so as to receive the fluid to be separated; alternatively, the cyclone units can be used as separators in a plurality of series or parallel or in the form of assemblies.

The assembly body comprises a shell, an upper orifice plate and a lower orifice plate, two ends of the shell are respectively connected with a pipeline of a fluid to be separated and a slag discharge pipe, and the side wall of the shell is also communicated with a separated fluid pipe; a plurality of mounting holes are uniformly formed in the upper orifice plate and the lower orifice plate, and the number of the mounting holes in the upper orifice plate and the number of the mounting holes in the lower orifice plate are the same; wherein the mounting holes are configured to match an outer dimension of the cyclone units to allow a plurality of the cyclone units to be fluid-tightly clamped between upper and lower orifice plates; the external dimension of the cyclone unit comprises the outer diameter of the shell or the outer diameter of the liquid inlet pipe. The upper orifice plate and the lower orifice plate have the same shape and size as the horizontal cross section of the assembling body shell, and can be further fixed in the inner cavity of the shell in a fluid-tight mode; the shell, the upper and lower pore plates and the outer wall of the cyclone unit jointly enclose a liquid discharge cavity, the liquid discharge cavity is communicated with the separated liquid pipe on the shell and is also communicated with a liquid outlet pipe penetrating through the side wall of the shell of the cyclone unit, so that a plurality of liquid discharge channels of the cyclone unit are provided.

The invention also provides a circulating fluidized bed heat exchange system which comprises the separator.

The invention also provides the application of the separator in a circulating fluidized bed heat exchange system.

Compared with the prior art, the scheme of the invention can at least obtain the following beneficial effects: compared with the traditional separator relying on a tangential inlet, the separator of the invention can cover the whole peripheral wall of the separator in the cyclone range without a cyclone dead zone; so that the whole peripheral wall of the separator is rubbed in the cyclone process without scaling; therefore, the situation that the scale flakes in the separator are peeled off to block the heat exchanger pipeline after long-term operation can be avoided; the separator adopts axial cyclone, the whole section of the cyclone unit shell or the liquid inlet pipe is used for inducing cyclone, and the whole flow resistance of the fluid to be separated is smaller, so that the pressure drop in the separation process is lower, and the treatment of the liquid to be separated with larger flow can be realized by smaller equipment size; under the same condition, the cyclone strength caused by the cyclone blades in the separator is weaker than that caused by a tangential inlet, the separation requirement of the circulating fluidized bed heat exchanger can be well matched, namely, heavier externally-introduced particles are effectively separated from a main flow, and meanwhile, lighter small scale pieces stripped from the surface of the heat exchanger are discharged from a liquid outlet pipe along with the main flow and are further separated; the characteristic is favorable for keeping the purity of the externally introduced particles in the continuous operation process, prevents the fine scale pieces from being input into the heat exchanger again along with the externally introduced particles, reduces the risk of bridging and blocking of the particles in the dipleg, and further avoids the scale formation degree in the heat exchanger from aggravating or blocking the heat exchanger.

Drawings

FIG. 1 shows a cyclone unit without a guide cone;

FIG. 2 is a cyclone unit with an upstream cone;

FIG. 3 is a cyclone unit with a downstream cone;

FIG. 4 is a cyclone unit with dual guide cones;

FIG. 5 is a schematic view of a housing of the cyclone unit;

FIG. 6 is a schematic view of an upper-inlet lower-outlet type cyclone unit with cyclone blades arranged in a flaring transition liquid inlet pipe;

FIG. 7 is a schematic view of an upper-inlet lower-outlet type cyclone unit with cyclone blades arranged in a non-transition liquid inlet pipe;

FIG. 8 is a schematic of a side-in, top-out cyclone unit;

FIG. 9 is a schematic of an upper inlet side outlet cyclone unit;

FIG. 10 is a schematic view of a lower inlet and upper outlet cyclone unit;

FIG. 11 is a schematic of a direct parallel combination of a plurality of cyclone units;

FIG. 12 is a schematic view of a plurality of cyclone units combined in parallel to form an assembly;

FIG. 13 is a schematic of an embodiment having four tangential inlet separators;

FIG. 14 is a scale layer of a single tangential inlet separator inner wall practical for use in a circulating fluidized bed heat exchanger.

In the figure: 1 is the inlet, 2 is the upper reaches awl, 3 is the casing, 31 is the cylinder section, 32 is the collection sediment section, 4 is the whirl blade, 5 is the drain pipe, 51 is the inducer, 6 is the low reaches awl, 7 is row's cinder notch, 8 is the fluid pipe of treating to separate, 9 is the transition pipe, 10 is row's cinder pipe, 11 is the post-separation fluid pipe, 12 is the shell, 13 is the feeding branch pipe, 14 is row's sediment branch pipe, 15 is the feed liquor pipe, 16 is the tangential import, 17 is the upper orifice plate, 18 is the lower orifice plate.

Detailed Description

Example 1

A separator for a circulating fluidized bed comprising a cyclone unit as shown in figures 1-7, said cyclone unit being of an inlet-outlet flow path arrangement comprising a housing 3, said housing 3 being of cylindrical configuration; the slag tapping device also comprises a liquid inlet 1 arranged at the upper end of the shell 3, a slag discharging port 7 arranged at the lower end of the shell 3, and a rotational flow blade 4 fixedly arranged at the upper part of the inner cavity of the shell 3 or in a liquid inlet pipe 15; the swirl vanes 4 are used for inducing swirl of the fluid to be separated; the swirl vanes 4 are provided with a central shaft coaxially arranged with the cylindrical section and 6 fan blades uniformly arranged on the side wall of the central shaft, the outer edges of the fan blades form the outer edge diameter dd of the swirl vanes 4, the side wall of the central shaft forms the root circle diameter dx of the swirl vanes 4, wherein dd/dx is 4.

The cyclone unit also comprises a liquid outlet pipe 5 which penetrates through the side wall of the shell 3 and extends into the inner cavity of the cylindrical structure; the liquid outlet pipe 5 is provided with an inlet section 51 which is positioned inside the shell 3 and is coaxial with the shell 3, the inlet section 51 is provided with an opening which is arranged upwards and a closed peripheral wall, and the opening of the inlet section 51 is positioned below the swirl vanes 4; the liquid outlet pipe 5 is used for leading out the fluid separated from the externally-introduced particles from the central part of the inner cavity of the shell 3. The inner diameter D of the inlet section 51 is 0.8 times the inner diameter D of the housing 3, i.e. D is 0.8D, so that an annular gap for the separated externally-introduced particles to slide down is formed between the outer wall of the inlet section 51 and the inner wall of the housing 3; the annular gap is communicated with a slag discharge port 7.

Preferably, as shown in fig. 2 to 4, the cyclone unit may further include an upstream cone 2 and/or a downstream cone 6 provided on an upper and/or lower surface of the central shaft for cooperating with the cyclone blades 4 to improve the cyclone separation effect.

As shown in fig. 5, the top of the cyclone unit is directly connected with the circulating fluidized bed heat exchanger through a fluid pipe 8 to be separated; or as shown in fig. 6-7, the top of the cyclone unit is connected with the fluid pipe 8 to be separated through a fluid inlet pipe 15; and the swirl vanes 4 can also be arranged in the liquid inlet pipe 15; the inlet pipe may be connected to the top end of the housing 3 via a transition pipe 9 for supplying the cyclone unit with the fluid to be separated.

Example 2

Different from embodiment 1, in this embodiment, the inlet section 51 is a mesh structure, and a plurality of meshes are uniformly formed on the end portion (the end far away from the rest portion of the liquid outlet pipe) and the peripheral wall thereof, and the aperture of the mesh is smaller than the diameter of the externally-introduced particles (in this embodiment, the externally-introduced particles are stainless steel particles with the diameter of 2 mm).

Comparative example 1

In contrast to example 1, in this comparative example dd/dx is 5.

Comparative example 2

In contrast to example 1, in this comparative example, D is 0.85D.

Example 3

A separator for a circulating fluidized bed comprising a cyclone unit as shown in fig. 8, said cyclone unit being in a side-in-top-out flow path arrangement comprising a housing 3, said housing 3 being of a closed-topped cylindrical structure; a liquid inlet pipe 15 penetrates through the upper part of the side wall of the shell 3; a liquid outlet pipe 5 coaxial with the shell 3 penetrates through the top of the shell 3; the bottom opening of the liquid outlet pipe 5 extends to the lower part of the liquid inlet pipe 15; the rotational flow blades 4 are fixedly arranged on the outer wall of the liquid outlet pipe 5. In the present embodiment, dd/dx is 3; d is 0.7D.

The side-in and up-out cyclone unit of the embodiment can be directly used as a separator of the circulating fluidized bed heat exchanger by connecting the liquid inlet pipe 15 to the fluid pipe 8 to be separated.

Example 3

A separator for a circulating fluidized bed comprising a cyclone unit as shown in figure 9, the cyclone unit being of an inlet-side outlet flow path arrangement comprising a housing 3, the housing 3 being of cylindrical configuration; a liquid outlet pipe 5 penetrates through the upper part of the side wall of the shell 3; the top end of the shell 3 is provided with a liquid inlet 1; the inlet section 51 of the liquid outlet pipe 5 is arranged coaxially with the shell 3; the swirl vanes 4 are fixedly arranged on the outer wall of the inlet section 51. In the present embodiment, dd/dx is 2; d is 0.6D.

The side-in and up-out cyclone unit can be directly used as a separator of the circulating fluidized bed heat exchanger by connecting the liquid inlet 1 to the fluid pipe 8 to be separated.

Example 4

A separator for a circulating fluidized bed comprising a cyclone unit as shown in figure 10, said cyclone unit employing a bottom-in-top-out flow path arrangement comprising a housing 3; the shell 3 comprises a cylindrical section 31 with a closed top at the upper part and a slag collecting section 32 at the lower part and in fluid communication with the cylindrical section 31; the slag collecting section 32 is provided with an inclined bottom, and the lowest end of the bottom is connected with the slag discharging port 7 so as to be beneficial to the aggregation and discharge of externally introduced particles; the top of the cylindrical section 31 is provided with a liquid outlet pipe 5 which is coaxial with the cylindrical section; the cyclone unit of this embodiment further comprises a liquid inlet pipe 15 penetrating through the inclined bottom of the slag collecting section 32 and extending into the cylindrical section; the top opening of the liquid inlet pipe 15 is positioned below the bottom opening of the liquid outlet pipe 5, and the liquid inlet pipe 15 is internally provided with swirl vanes 4. In the present embodiment, dd/dx is 3; d is 0.5D.

The lower-inlet and upper-outlet type cyclone unit can be directly used as a separator of the circulating fluidized bed heat exchanger by connecting the liquid inlet pipe 15 to the fluid pipe 8 to be separated.

Example 5

A separator for a circulating fluidized bed heat exchanger, as shown in FIG. 11, comprises at least two cyclone units, liquid inlets 1 or liquid inlet pipes 15 (not shown in FIG. 11) of which are connected to fluid pipes 8 to be separated through a plurality of feed branch pipes 13, respectively; the slag discharge ports 7 of the at least two rotational flow units are respectively connected to the slag discharge pipe 10 through a plurality of slag discharge branch pipes 14. The cyclone unit described in this embodiment is the cyclone unit described in embodiment 1.

Example 6

A separator for a circulating fluidized bed heat exchanger is an assembly body consisting of a plurality of cyclone units, as shown in figure 12, the assembly body comprises an upper orifice plate 17 and a lower orifice plate 18 of a shell 12, two ends of the shell 12 are respectively connected with a fluid pipeline 8 to be separated and a slag discharge pipe 10, and the side wall of the shell 12 is also communicated with a separated fluid pipe 11; a plurality of mounting holes are uniformly formed in the upper orifice plate 17 and the lower orifice plate 18, the positions of the mounting holes in the upper orifice plate 17 and the lower orifice plate 18 correspond to each other, and the number of the mounting holes in the upper orifice plate and the number of the mounting holes in the lower orifice plate are the same; wherein the mounting holes are configured to match the outer dimensions of the cyclone units to allow a plurality of the cyclone units to be fluid-tightly clamped between upper and lower orifice plates; the outer dimension of the cyclone unit refers to the outer diameter of the housing 3 or the liquid inlet pipe 15. The upper orifice plate 17 and the lower orifice plate 18 have the same shape and size as the horizontal cross section of the housing 12 of the fitting body and can be fixed in the inner cavity of the housing 12 in a fluid-tight manner; the shell 12, the upper and lower pore plates and the outer wall of the cyclone unit together enclose a liquid discharge cavity, the liquid discharge cavity is communicated with the separated fluid pipe 11 on the shell and is also communicated with the liquid outlet pipe 5 penetrating through the side wall of the shell of the cyclone unit, so that a plurality of liquid discharge channels of the cyclone unit are provided.

The cyclone unit described in this embodiment is the cyclone unit described in embodiment 1.

Example 7

A separator for a circulating fluidized bed heat exchanger, as shown in fig. 13, comprises a cylindrical shell 3, four tangential inlets 16 uniformly arranged at the upper part of the shell 3, a liquid outlet pipe 5 is arranged through the side wall of the shell 3, an inlet section 51 of the liquid outlet pipe is arranged coaxially with the shell 3, and the opening of the liquid outlet pipe is positioned below the tangential inlets; the bottom of the shell 3 is communicated with a slag discharge port.

Comparative example 3

In contrast to example 7, this example uses a single tangential inlet.

Example 8

A circulating fluidized bed heat exchanger system comprising any one of the separators described in embodiments 1-7.

Example 9

Use of a separator as in any one of examples 1 to 7 in a circulating fluidized bed heat exchanger system.

Separation Performance test

Testing equipment: the housings and/or the shells of examples 1 to 7 and comparative examples 1 to 3 were made of a transparent acryl material so as to observe whether a cyclone dead zone was present inside the separator; wherein, the cyclone units/separators in examples 1-7 and comparative examples 1-3 have the same shell diameter, and the size parameters of the liquid outlet pipe and the blades are configured according to the definition of each example/comparative example, wherein, each example/comparative example corresponds to the inlet of the separator and is provided with a flow meter so as to obtain the inlet flow rate of the separator; a differential pressure transmitter is arranged between the liquid inlet and the slag discharge port to obtain the operating pressure drop of the separator;

externally guiding particles: stainless steel particles with the diameter of 0.8-3 mm;

fluid system to be separated: simulating a fluid to be separated containing fine scale pieces by using a mixed fluid of quartz sand with the diameter of 300-600 microns and water;

separator inlet flow rate: the separation performance of each example was tested at inlet flow rates of 0.3m/s, 0.6m/s, 1m/s, 1.5m/s, respectively.

The test method and the purpose are as follows: using the testing devices corresponding to examples 1-7 and comparative examples 1-3, it was tested whether a cyclone dead zone exists inside the separator, a pressure drop (Pa) between the liquid inlet and the slag discharge port of the separator, and a clear division (sand-steel ratio, wt%) of the externally introduced particles and the fine scale pieces could be formed under the same inlet flow rate.

The test results were as follows:

based on the above test results, it can be seen that: according to the invention, the cyclone dead zone in the separator can be effectively eliminated even by the separator corresponding to the comparative examples 1-2 under various flow speed conditions, so that the inner wall of the separator is prevented from scaling, and the risk that a large scale piece falls off to block the heat exchange tube is eliminated; examples 1-7 of the present invention have a greatly reduced operating pressure drop during separation compared to a single tangential inlet separator at the same inlet flow rate; under the condition of meeting the adjustment of the ratio range of the excircle diameter and the root circle diameter of the swirl vane, the inlet flow speed during separation is allowed to be increased to 1m/s, and meanwhile, the clear division of externally introduced particles and small scale pieces can be realized, so that the treatment capacity of the separator can be remarkably increased, and the size of equipment is allowed to be further reduced.

The above is only an example of the preferred embodiment of the technical solution of the present invention, which should not be understood as a limitation to all possible ways of the technical solution of the present invention, and the solution obtained by simple replacement, combination and other modifications without creative efforts by those of ordinary skill in the art also belongs to the protection scope of the present invention.

Claims

1. A separator for heat exchange in a circulating fluidized bed, said separator comprising at least one cyclone unit, said cyclone unit comprising a housing (3), characterized in that: the shell (3) is communicated with a fluid outlet to be separated of the circulating fluidized bed heat exchanger through a fluid pipe (8) to be separated so as to supply the fluid to be separated containing externally introduced particles and fine scale pieces into the shell (3); the housing (3) comprises at least one cylindrical section (31); the cyclone unit comprises at least three tangential inlets or cyclone blades (4) arranged coaxially with the cylindrical section (31) of the housing (3), the cyclone blades (4) being used to induce a cyclone of the fluid to be separated; the cyclone unit further comprises a liquid outlet pipe (5) extending to the cylindrical section (31) of the housing (3); at least an inlet section (51) of the liquid outlet pipe (5) is coaxially arranged with the cylindrical section (31) of the shell (3), and the liquid outlet pipe (5) is used for leading out a main body flow of the fluid to be separated after the externally-introduced particles are separated; the bottom of the shell (3) is provided with a slag discharge port (7) for discharging externally-introduced particles.

2. The separator of claim 1, wherein: the at least three tangential inlets are evenly distributed at the same height in the upper part of the housing.

3. The separator of claim 1, wherein: the top end of the shell (3) is formed into a liquid inlet (1), and the bottom end of the shell is communicated with a slag discharge port (7); the liquid outlet pipe (5) penetrates through the side wall of the shell (3), and the liquid outlet pipe (5) is located below the swirl vanes (4).

4. A separator as claimed in claim 3, wherein: the separator comprises at least two cyclone units, and a liquid inlet (1) of each cyclone unit is respectively communicated with a fluid pipe (8) to be separated through a feeding branch pipe (13); and the slag discharge port (7) of each cyclone unit is respectively communicated with the slag discharge pipe (10) through a slag discharge branch pipe (14).

5. A separator as claimed in claim 3, wherein: the separator comprises at least two cyclone units, and further comprises a shell (12), an upper pore plate (17) and a lower pore plate (18) which are fixedly arranged in the shell (12), two ends of the shell (12) are respectively connected with a fluid pipe (8) to be separated and a slag discharge pipe (10), and the side wall of the shell (12) is also communicated with a separated fluid pipe (11); a plurality of mounting holes are uniformly formed in the upper orifice plate (17) and the lower orifice plate (18), and the number of the mounting holes in the upper orifice plate and the number of the mounting holes in the lower orifice plate are the same; each cyclone unit is clamped between the upper and lower pore plates in a fluid sealing manner; the shell (12), the upper and lower pore plates and the outer wall of the cyclone unit jointly enclose a liquid discharge cavity, and the liquid discharge cavity is communicated with the separated fluid pipe (11) on the shell (12) and is also communicated with the liquid outlet pipe (5) penetrating through the side wall of the shell (12) of the cyclone unit.

6. The separator of claim 1, wherein: the top end of the shell (3) is closed, and the upper part of the cylindrical section (31) is provided with a liquid inlet pipe (15); the liquid outlet pipe (5) penetrates through the closed top of the shell (3) and extends to the lower part of the liquid inlet pipe (15); the cyclone blades (4) are fixedly arranged on the outer wall of the liquid outlet pipe (5) below the liquid inlet pipe (15).

7. The separator of claim 1, wherein: the top end of the shell (3) is formed into a liquid inlet (1), and the bottom end of the shell is communicated with a slag discharge port (7); the liquid outlet pipe (5) penetrates through the side wall of the shell (3), and an inlet section (51) of the liquid outlet pipe (5) is downward opened; the swirl vanes (4) are fixedly arranged at an annular gap formed by the inlet section (51) and the shell (3).

8. The separator of claim 1, wherein: the shell (3) comprises a cylindrical section (31) with a closed upper end and a slag collecting section (32) which is connected to the lower end of the cylindrical section (31) and is provided with an inclined bottom, and the liquid outlet pipe (5) and the cylindrical section (31) are coaxially arranged at the closed top; the liquid inlet pipe (15) and the cylindrical section (31) are coaxially arranged and extend into the cylindrical section (31) through the inclined bottom of the slag collecting section (32); the swirl vanes (4) are fixedly arranged in the liquid inlet pipe (15).

9. The separator of any one of claims 3-8, wherein: the inlet section (51) of the outlet pipe (5) has an inner diameter D, and the housing (3) has an inner diameter D; wherein: d is less than or equal to 0.8D; to provide sufficient clearance for the movement of the externally-introduced particles; the cyclone blades (4) comprise a center shaft with a circular section and a plurality of fan blades uniformly fixed on the outer side of the center shaft, the outer edges of the fan blades limit the diameter dd of the outer circle of the cyclone blades, the side wall of the center shaft limits the diameter dx of the root circle of the cyclone blades, and dd/dx is less than or equal to 4 so as to provide clear division of externally introduced particles and small scale pieces.

10. The separator of claim 9, wherein: the inlet section (51) is of a mesh structure, a plurality of meshes are uniformly arranged on the end part and the peripheral wall of the inlet section, and the aperture of each mesh is smaller than the diameter of the externally-introduced particles.