CN102235665B

CN102235665B - Connection between cyclone separators and hearth of large-scale circulating fluidized bed boiler

Info

Publication number: CN102235665B
Application number: CN201010162777.XA
Authority: CN
Inventors: 那永洁; 孙运凯; 宋国良; 高鸣; 包绍麟; 吕清刚
Original assignee: Institute of Engineering Thermophysics of CAS
Current assignee: Institute of Engineering Thermophysics of CAS
Priority date: 2010-04-28
Filing date: 2010-04-28
Publication date: 2014-05-14
Anticipated expiration: 2030-04-28
Also published as: CN102235665A

Abstract

The invention discloses connection between cyclone separators and a hearth of a large-scale circulating fluidized bed boiler. The hearth is connected with six cyclone separators. A cross section of the hearth is rectangular, wherein upper portions of two wider side walls of the hearth are provided with three flue gas outlets respectively. The six cyclone separators are divided into two sets equally and are fixedly connected with the two wider side walls. Each flue gas outlet is communicated with an inlet flue of the cyclone separator. Cylindrical shell structure and dimension of the six cyclone separator are same. In the two set of cyclone separators on the two side walls, inlet flue cross section of each cyclone separator of each set and inlet flue cross section of each cyclone separator of the other set form central symmetry relative to a central point of the hearth. Inlet flue cross sections of two outboard cyclone separators of the sets form axial symmetry relative to a center line of the hearth. According to the connection provided in the invention, flow of flue gas in the hearth is distributed uniformly, flue gas flux of each cyclone separator is distributed uniformly, particle concentration of a vertical cross section of the inlet flue is in reasonable distribution, thus performance consistency of each cyclone separator is ensured.

Description

Being connected between the cyclone separator of large circulating fluidized bed boiler and burner hearth

Technical field

The present invention relates to Sector of Cfb Boilers, particularly the gas-solid separating device of CFBB.

Background technology

Cyclone separator is one of vitals of CFBB, its Main Function is that the high-temp solid material that in a large number leaves burner hearth with flue gas is separated from flue gas, send burner hearth back to by material returning device, to maintain the ciculation fluidized state of burner hearth, make that fuel burns repeatedly, desulfurizing agent reacts repeatedly, reach desirable efficiency of combustion and desulfuration efficiency.The separating property of cyclone separator directly affects the performance of whole CFBB.

At present, Technology of Circulating Fluidized Bed Boiler is just towards maximizing and high parameter future development, both domestic and externally all concentrates on subcritical and supercritical circulating fluidized bed boiler field about research and development.Because the size of large circulating fluidized bed boiler burner hearth is very large, and the size of cyclone separator cannot be synchronizeed with the size of burner hearth and increased, current known way is to mate with a burner hearth with multiple cyclone separators, has produced thus the method for arranging of multiple cyclone separators.Such as, the 210MW CFBB of Xi'an hot working research institute design is arranged symmetrically with four cyclone separators on the side wall of the left and right of burner hearth; The left and right side wall of the 600MW supercritical circulating fluidized bed boiler hearth of ALSTOM company of France design is arranged symmetrically with six cyclone separators; The 800MW supercritical circulating fluidized bed boiler Conceptual Design that Tsing-Hua University proposes also adopts the parallel layout of six cyclone separators.

Multiple cyclone separators and a burner hearth parallel join are the new problems occurring in CFBB large scale development, have become one of key issue of supercritical circulating fluidized bed boiler design.Published result of study shows, in the time exceeding that two cyclone separators are parallel to be arranged, the Gas-solid Two-phase Flow of cyclone separator inside presents heterogeneity, and between multiple cyclone separators, flue gas flow distributes uneven; Different gas approach arranges that affecting burner hearth flue gas flow distributes and the distribution character of granule density in gas approach, and the layout of multiple outlets of burner hearth has impact to the flow of flue gas in burner hearth and distribution of particles; In some large circulating fluidized bed boiler runnings, also there is the uneven phenomenon of this distribution.

Be subject to the restriction of CFBB entire arrangement, the gas approach of cyclone separator is all shorter, belong to short gas approach, in gas approach, the acceleration degree of particle is very limited, and the distribution character of particle on the vertical cross-section of gas approach directly affects the separative efficiency of cyclone separator, the performance of the cyclone separator of short gas approach is relevant with the layout of gas approach, namely relevant with the angle of the relative burner hearth of gas approach with the position of furnace outlet.In the time that large-sized burner hearth is in parallel with multiple cyclone separators, the importance of this relation is just more outstanding, and becomes complicated.

For the problems referred to above, one of published solution is, installs deflector additional to improve the impact on Cyclone Performance at entrance, is structurally difficult to realize but guide vane is set in the outlet that highly reaches 6 meters, width and reach 4 meters; Two of published solution is, vertical partition wall is set in burner hearth, the space of burner hearth is cut apart, to avoid the layout of furnace outlet on the symmetric impact of flow of flue gas in burner hearth, but this structural deterioration flue gas blending on a large scale in burner hearth, and the abrasionproof of partition wall and suspention problem are all difficult to resolve certainly very much; Three of published solution is, all arrange even number cyclone separator in the every side of burner hearth, for large circulating fluidized bed boiler, on the side wall of burner hearth left and right, need to arrange respectively four cyclone separators, but when four cyclone separators are arranged side by side, shared horizontal space is well beyond the horizontal space that provides of furnace width, although can adopt the method that reduces cyclone separator diameter to solve Layout Problem, the performance of cyclone separator will decline greatly.

Summary of the invention

The object of the invention is, overcome the shortcoming of prior art, being connected between a kind of cyclone separator of large circulating fluidized bed boiler and burner hearth is provided, the method of arranging for six cyclone separator juxtapositions of large circulating fluidized bed boiler, make the flow distribution of flue gas in burner hearth even, and the flue gas flow of six cyclone separators is uniformly distributed, on the vertical cross-section of the gas approach of six cyclone separators, granule density distributes rationally, guarantees that six Cyclone Performances are consistent.

For achieving the above object, technical solution of the present invention is:

Being connected between a kind of cyclone separator of large circulating fluidized bed boiler and burner hearth, for burner hearth is connected with six cyclone separators; Its each cyclone separator forms by gas approach and cylindrical shell; Burner hearth (10) cross section (BKQN) is rectangle, wherein the top of wider both walls is respectively equipped with three exhanst gas outlets, six cyclone separators are divided into two groups, be fixed in respectively in both walls, each exhanst gas outlet is all connected with the gas approach of a cyclone separator; Wherein,

A) tube structure of six cyclone separators and size are all identical;

B) be positioned at two groups of cyclone separators in both walls, the gas approach cross section of three cyclone separators of every group, with the gas approach cross section of three cyclone separators of another group, about burner hearth central point (R) Central Symmetry;

C) be positioned at two groups of cyclone separators in both walls, the gas approach cross section of every group of outermost two cyclone separators, about burner hearth center line (JP) axial symmetry.

Described every group of outermost cyclone separator, the angle (a) that the burner hearth both walls (BK, QN) that the outer side edges (AB) of its gas approach cross section (ABDC) is connected with it becomes is 90～110 °; The angle (b) that the outer side edges (AB) of its gas approach cross section (ABDC) becomes with inner side edge (CD) is 0～30 °, and wherein angle (b) is 0 ° and refers to that outer side edges (AB) and inner side edge (CD) are parallel to each other.

The angle (c) that the burner hearth both walls (BK, QN) that the outer side edges (FE) of the cross section (FEHG) of the gas approach of the cyclone separator in the middle of described every group is connected with it becomes is less 0～10 ° than angle (a).

Described angle (c) >=90 °.

The position of the intersection point (E) of the burner hearth both walls (BK, QN) that the outer side edges (FE) of the gas approach cross section (FEHG) of the cyclone separator in the middle of described every group is connected with it meets BE=BK/3 ± 10%.

Angle (d) >=angle (b) that the outer side edges (FE) of the cross section (FEHG) of the gas approach of the cyclone separator in the middle of described every group becomes with inner side edge (GH).

The gas approach A/F (EH) of described cyclone separator in the middle of every group, with the pass of the gas approach A/F (BD) of every group of outermost cyclone separator is: EH=BD ± 2%.

Being connected between the cyclone separator of large circulating fluidized bed boiler provided by the invention and burner hearth, by the position of burner hearth exhanst gas outlet and the shape of cyclone inlet flue are rationally set, make the flow distribution of flue gas in burner hearth even, and the flue gas flow of six cyclone separators is uniformly distributed, granule density distributes rationally on the vertical cross-section of gas approach, has guaranteed that each Cyclone Performance is consistent.

Accompanying drawing explanation

Fig. 1 is the schematic top plan view that is connected embodiment 1 between cyclone separator and the burner hearth of large circulating fluidized bed boiler of the present invention;

Fig. 2 is the schematic top plan view that is connected embodiment 2 between cyclone separator and the burner hearth of large circulating fluidized bed boiler of the present invention;

Fig. 3 is the schematic top plan view that is connected embodiment 3 between cyclone separator and the burner hearth of large circulating fluidized bed boiler of the present invention.

The specific embodiment

Referring to Fig. 1,2,3, being connected between the cyclone separator of large circulating fluidized bed boiler of the present invention and burner hearth, it is the corner location that cyclone separator 1,3,4,6 is arranged in to burner hearth cross section BKQN, the central point R symmetry of these four relative burner hearths of cyclone separator, can make to greatest extent flue gas be full of burner hearth four angles, avoid occurring in bight that flue gas is detained or eddy flow phenomenon and make the flue gas flow of cyclone separator 1,3,4,6 basic identical.

A=90～110 °, angle that the limit BK of the burner hearth cross section BKQN that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 is connected with it becomes; Angle b=0～30 ° that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 becomes with inner side edge CD; Due to cyclone separator the 1,3,4, the 6th, about the central point R symmetry of burner hearth, therefore the gas approach structure of cyclone separator 3,4,6 is identical with cyclone separator 1.By the above-mentioned angle between gas approach and burner hearth, above-mentioned shape with gas approach, flue gas is entered after the gas approach of cyclone separator, the ash that flue gas is carried secretly is to the outer side edges enrichment of gas approach, and flow into cyclone separator along gas approach outer side edges, thereby guarantee that the gas solid separation efficiency of cyclone separator reaches sufficiently high level.

The opening of cyclone separator 2 and 5 gas approach that are connected with burner hearth side wall, be not positioned at the centre position of burner hearth side wall, and 4 separators of the shape of gas approach and all the other also may not be identical.Put into practice verifiedly, if simple according to the physical dimension of cyclone separator 1, in burner hearth side wall centre position, separator 2 and 5 is set, the exhaust gas volumn of these two cyclone separators can significantly be less than other 4, and separative efficiency is also significantly on the low side.The aperture position of cyclone separator 2 of the present invention and 5 gas approach that are connected with burner hearth side wall is offset to BE=BK/3 ± 10% to its gas approach outer side edges direction, can make burner hearth flue gas enter after gas approach, the grey outward side enrichment that flue gas is carried secretly, thus the separative efficiency of these two separators guaranteed; Simultaneously, reduce the outer side edges FE of gas approach cross section and the interior angle c on burner hearth cross section BK limit, make a-c=0～10 °, can avoid burner hearth flue gas directly to wash away central tube, cause flue gas carrying solid particle secretly directly from central tube short circuit effusion, thereby further guarantee that cyclone separator 2 and 5 separative efficiencies can not reduce; In addition, by changing the gas approach outer side edges of cyclone separator 2 and 5 and the angle d of inner side edge, make d >=b, and make EH=BD ± 2%, the exhaust gas volumn that further assurance enters cyclone separator 2 and 5 is suitable with all the other 4 separators, thereby the flue gas flow that guarantees six separators is even, and guarantee the uniformity of flow of flue gas on burner hearth cross section.

Because in the BK of burner hearth BKQN side, the opening EH deflection BN side of the gas approach of middle cyclone separator 2 on burner hearth, this makes burner hearth produce the tendency of deflection BN side near BK side wall place flue gas.In order to correct this tendency, in the NQ of burner hearth BKQN side, the KQ side of the opening deflection burner hearth of the gas approach of cyclone separator 5 correspondences on burner hearth in the middle of making, therefore make cyclone separator 5 and the central point R symmetry of cyclone separator 2 with respect to burner hearth BKQN, on the whole cross section BKQN of burner hearth, realized like this flow of flue gas symmetrically and evenly and distributed.

In actual applications, the opening of the gas approach of cyclone separator 1～6 on burner hearth may be enlarging form, the inner side edge and/or the outer side edges that are cross section are the broken line that two straightways form, now the straightway of the close Membrane Separator Cylinder for CFB Boiler of outer side edges and inner side edge is to the extended line of burner hearth direction, enclose with burner hearth side wall the quadrangle forming, still meet above-mentioned feature of the present invention; Above-mentioned separator inlet flue opening width is now gas approach cross section side near the straightway of Membrane Separator Cylinder for CFB Boiler to the distance between the extended line of burner hearth direction and two intersection points of burner hearth side wall.

Illustrate below in conjunction with embodiment.

Embodiment 1

Fig. 1 is the top of large circulating fluidized bed boiler burner hearth and six cyclone separators of the embodiment of the present invention 1, in figure, represents burner hearth and the cyclone separator elementary contour on top view with single line bar, is the internal face of flue gas circulation.The parameter such as concrete structure and thickness of these walls and task of the present invention are irrelevant, in figure, do not represent.Rectangle BKQN represents the cross section of the burner hearth being surrounded by four side walls, and four jiaos, burner hearth may be with corner cut sometimes, still can be similar to and think that cross section is rectangle.

Six cyclone separators are all made up of cylindrical shell and gas approach, and six cyclone separators are connected with burner hearth exhanst gas outlet by gas approach separately respectively.The tube structure of six separators and size are all identical.

Cyclone separator 1,2,3 is arranged side by side in the BK side of burner hearth successively, and cyclone separator 4,5,6 is arranged side by side in the NQ side of burner hearth successively, and BK limit and NG limit are the long limit of burner hearth cross section; On the gas approach cross section of cyclone separator 1, have outer side edges AB and the inner side edge CD of gas approach, the opening that BD is gas approach is also one of six exhanst gas outlets of burner hearth simultaneously.

The cross section of the gas approach of cyclone separator 1, cyclone separator 2, cyclone separator 3, with the cross section of the gas approach of cyclone separator 4, cyclone separator 5, cyclone separator 6, about burner hearth central point R Central Symmetry; The cross section of the gas approach of cyclone separator 1 and cyclone separator 4, with the cross section of the gas approach of cyclone separator 3 and cyclone separator 6, about burner hearth center line JP axial symmetry.

Take cyclone separator 1 and 2 as example, the restriction that the every side of burner hearth is positioned to the cyclone separator in centre position is described.

The structure of cyclone separator 2 and size and 1 basic identical, difference is only on gas approach.The outer side edges FE of the gas approach FEHG of cyclone separator 2 is positioned at the left side of inner side edge GH, identical with the interior outside relation of the gas approach of cyclone separator 1.

The angle a that the limit BK of the burner hearth cross section BKQN that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 is connected with it becomes is 100 °; The angle b that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 becomes with inner side edge CD is 10 °.

The angle c that the limit BK of the burner hearth cross section BKQN that the outer side edges FE of the cross section FEHG of the gas approach of cyclone separator 2 is connected with it becomes is less 5 ° than angle a; The tie point E position of the outer side edges FE of the gas approach cross section FEHG of cyclone separator 2 and burner hearth 10 limit BK is BE=BK/3; D > angle, the angle b that the outer side edges FE of the cross section FEHG of the gas approach of cyclone separator 2 becomes with inner side edge GH, the pass of the gas approach A/F BD that the gas approach A/F EH that burner hearth 10 is connected with cyclone separator 2 is connected with cyclone separator 1 with burner hearth 10 is EH=BD.

Above-mentioned angle and length relation can suitably be adjusted within the specific limits, concrete:

The angle a that the limit BK of the burner hearth cross section BKQN that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 is connected with it becomes can be 90～110 °; The angle b that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 becomes with inner side edge CD can be 0～30 °, and wherein angle b is 0 ° and refers to that outer side edges AB and inner side edge CD are parallel to each other;

The angle c that the limit BK of the burner hearth cross section BKQN that the outer side edges FE of the cross section FEHG of the gas approach of cyclone separator 2 is connected with it becomes is less 0～10 ° than angle a; The outer side edges FE of the gas approach cross section FEHG of cyclone separator 2 and burner hearth 10 are BE=BK/3 ± 10% at the link position E of burner hearth cross section FEHG point; The pass of the gas approach A/F BD that the gas approach A/F EH that burner hearth 10 is connected with cyclone separator 2 is connected with cyclone separator 1 with burner hearth 10 is EH=BD ± 2%.

Need to annotatedly be, in figure, be positioned at 4 separators 1,3,4,6 of four jiaos, burner hearth, take cyclone separator 1 as example, the outside AB of gas approach and the summit B of burner hearth BKQN are same point, the expression of just simplifying, in actual design, in the consideration of structure processing, these 2 do not overlap often.

Embodiment 2

Fig. 2 is the top of large circulating fluidized bed boiler burner hearth and six cyclone separators of the embodiment of the present invention 2.Rectangle BKQN represents the cross section of the burner hearth being surrounded by four side walls.

Take cyclone separator 1 and 2 as example, the restriction to the cyclone separator in the middle of the every side of burner hearth is described.

The structure of cyclone separator 2 and size and 1 basic identical, difference is only on gas approach.The outside FE of the gas approach FEHG of cyclone separator 2 is positioned at the left side of inner side GH, identical with the interior outside relation of the gas approach of cyclone separator 1.

The angle a that the limit BK of the burner hearth cross section BKQN that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 is connected with it becomes is 90 °; The angle b that the outer side edges AB of the gas approach cross section ABDC of cyclone separator 1 becomes with inner side edge CD is 15 °.

The angle c that the limit BK of the burner hearth cross section BKQN that the outer side edges FE of the cross section FEHG of the gas approach of cyclone separator 2 is connected with it becomes is less 0 ° than angle a, and angle c is also 90 °; The gas approach of cyclone separator 2 and burner hearth 10 are BE=BK/3+10% at the link position of burner hearth cross section FEHG; D=angle, the angle b that the outer side edges FE of the cross section FEHG of the gas approach of cyclone separator 2 becomes with inner side edge GH, the pass of the gas approach A/F BD that the gas approach A/F EH that burner hearth 10 is connected with cyclone separator 2 is connected with cyclone separator 1 with burner hearth 10 is EH=BD.

Embodiment 3

As shown in Figure 3, the method of attachment of burner hearth and cyclone separator and embodiment 2 are in full accord, unique difference is, the opening of the gas approach of cyclone separator 1～6 on burner hearth is enlarging form, and the inner side edge of its cross section is the broken line that two straightways form.

The gas approach cross section of cyclone separator 1 is ABD " D ' C; outer side edges is AB; inner side edge is broken line CD ' D ", straightway CD ' near Membrane Separator Cylinder for CFB Boiler intersects at a D to extended line and the burner hearth side wall BK of burner hearth direction, and BD is the gas approach A/F that burner hearth 10 is connected with cyclone separator 1.

The gas approach cross section of cyclone separator 2 is FEH " H ' G; outer side edges is FE; inner side edge is broken line GH ' H ", straightway GH ' near Membrane Separator Cylinder for CFB Boiler intersects at a H to extended line and the burner hearth side wall BK of burner hearth direction, and EH is the gas approach A/F that burner hearth 10 is connected with cyclone separator 2;

On the gas approach cross section of cyclone separator 1, the angle b that limit AB becomes with limit CD ' is 15 °; On the gas approach cross section of cyclone separator 2, d=angle, the angle b that limit FE becomes with limit GH ';

The pass of the gas approach A/F BD that the gas approach A/F EH that burner hearth 10 is connected with cyclone separator 2 is connected with cyclone separator 1 with burner hearth 10 is EH=BD.

Claims

1. a burner hearth with the large circulating fluidized bed boiler that cyclone separator is attached thereto, this burner hearth is connected with six cyclone separators; It is characterized in that, each cyclone separator forms by gas approach and cylindrical shell; Burner hearth (10) cross section (BKQN) is rectangle, wherein the top of wider both walls is respectively equipped with three exhanst gas outlets, six cyclone separators are divided into two groups, be fixed in respectively in both walls, each exhanst gas outlet is all connected with the gas approach of a cyclone separator; Wherein,

A) tube structure of six cyclone separators and size are all identical; The gas approach cross section of each cyclone separator all has outer side edges and inner side edge, and described outer side edges and cyclone separator cylindrical shell wall seamlessly transit;

B) be positioned at two groups of cyclone separators in both walls, the gas approach cross section of three cyclone separators of every group of cyclone separator, with the gas approach cross section of three cyclone separators of another group, about burner hearth central point (R) Central Symmetry;

C) be positioned at two groups of cyclone separators in both walls, the gas approach cross section of every group of outermost two cyclone separators of cyclone separator, about burner hearth center line (JP) axial symmetry; And the angle b that the outer side edges (AB) of its gas approach cross section (ABDC) becomes with inner side edge (CD) is 0～30 °, wherein angle b is 0 ° and refers to that outer side edges (AB) and inner side edge (CD) are parallel to each other.

2. by the burner hearth of large circulating fluidized bed boiler claimed in claim 1, it is characterized in that, the outermost cyclone separator of described every group of cyclone separator, the angle a that the burner hearth both walls (BK, QN) that the outer side edges (AB) of its gas approach cross section (ABDC) is connected with it becomes is 90～110 °.

3. by the burner hearth of large circulating fluidized bed boiler claimed in claim 2, it is characterized in that, the angle c that the burner hearth both walls (BK, QN) that the outer side edges (FE) of the cross section (FEHG) of the gas approach of the cyclone separator in the middle of described every group of cyclone separator is connected with it becomes is less 0～10 ° than angle a.

4. by the burner hearth of large circulating fluidized bed boiler claimed in claim 3, it is characterized in that c >=90 °, described angle.

5. by the burner hearth of large circulating fluidized bed boiler claimed in claim 1, it is characterized in that, burner hearth both walls (the BK that the outer side edges (FE) of the gas approach cross section (FEHG) of the cyclone separator in the middle of described every group of cyclone separator is connected with it, the position of intersection point (E) QN) meets BE=BK/3 ± 10%, wherein, the intersection point of the burner hearth side wall that BE is connected with it for the outer side edges of the gas approach cross section of the cyclone separator in the middle of every group of cyclone separator, to with described intersection point close together, distance between the end points of the Projection Line Segment of described burner hearth side wall on described gas approach cross section, BK is the distance between the two-end-point of the put into operation line segment of described burner hearth side wall on described gas approach cross section.

6. by the burner hearth of large circulating fluidized bed boiler claimed in claim 1, it is characterized in that d >=angle, angle b that the outer side edges (FE) of the cross section (FEHG) of the gas approach of the cyclone separator in the middle of described every group of cyclone separator becomes with inner side edge (GH).

7. by the burner hearth of large circulating fluidized bed boiler claimed in claim 1, it is characterized in that, the gas approach A/F (EH) of the cyclone separator in the middle of described every group of cyclone separator, with the pass of the gas approach A/F (BD) of every group of outermost cyclone separator of cyclone separator be: EH=BD ± 2%, wherein, EH is the distance between outer side edges and inner side edge and two intersection points of its burner hearth side wall being connected of the gas approach cross section of the cyclone separator in the middle of every group of cyclone separator, distance between two intersection points of the outer side edges of the gas approach cross section that BD is every group of outermost cyclone separator of cyclone separator and inner side edge and its burner hearth side wall being connected.