CN201636851U - The connection between the cyclone separator and the furnace of a large circulating fluidized bed boiler - Google Patents

Abstract

The utility model discloses a connection between a cyclone separator and a furnace of a large-scale circulating fluidized bed boiler, which is that the furnace is connected with six cyclone separators; There are three flue gas outlets, and the six cyclone separators are divided into two groups, which are respectively fixed on the walls on both sides. Each flue gas outlet is connected to the inlet flue of a cyclone separator; among them, the six cyclone separators The cylinder structure and size of the device are the same; between the two groups of cyclone separators located on the two side walls, the cross-section of the inlet flue of each cyclone separator in each group is symmetrical with respect to the center point of the furnace; the most The cross-sections of the inlet flues of the two outer cyclones are axisymmetric with respect to the centerline of the furnace. The connection provided by the utility model makes the flow distribution of flue gas in the furnace uniform, and the flue gas flow rate of each cyclone separator is evenly distributed, and the particle concentration distribution on the vertical section of the inlet flue is reasonable, which ensures the performance of each cyclone separator unanimous.

Description

The connection between the cyclone separator and the furnace of a large circulating fluidized bed boiler

technical field

The utility model relates to the technical field of circulating fluidized bed boilers, in particular to a gas-solid separation device for circulating fluidized bed boilers.

Background technique

The cyclone separator is one of the important components of the circulating fluidized bed boiler. Its main function is to separate a large amount of high-temperature solid materials that leave the furnace with the flue gas from the flue gas, and send them back to the furnace through the feeder to maintain the circulating flow of the furnace. In the desulfurized state, the fuel is combusted repeatedly and the desulfurizer reacts repeatedly to achieve the ideal combustion efficiency and desulfurization efficiency. The separation performance of the cyclone separator directly affects the performance of the entire circulating fluidized bed boiler.

At present, circulating fluidized bed boiler technology is developing towards large-scale and high-parameter direction, and relevant research and development at home and abroad are concentrated in the field of subcritical and supercritical circulating fluidized bed boilers. Due to the large size of the hearth of a circulating fluidized bed boiler, the size of the cyclone separator cannot be increased synchronously with the size of the hearth. The current known method is to use multiple cyclone separators to match one hearth, resulting in multiple cyclones Separator layout method. For example, the 210MW circulating fluidized bed boiler designed by Xi'an Thermal Engineering Research Institute has four cyclone separators symmetrically arranged on the left and right side walls of the furnace; the left and right side walls of the 600MW supercritical circulating fluidized bed boiler designed by the French company ALSTOM are symmetrically arranged Six cyclone separators; the conceptual design scheme of the 800MW supercritical circulating fluidized bed boiler proposed by Tsinghua University also uses six cyclone separators to be arranged in parallel.

Parallel connection of multiple cyclone separators with one furnace is a new problem in the development of large-scale circulating fluidized bed boilers, and has become one of the key issues in the design of supercritical circulating fluidized bed boilers. The published research results show that when more than two cyclone separators are arranged in parallel, the gas-solid two-phase flow inside the cyclone separator presents non-uniformity, and the flue gas flow distribution among multiple cyclone separators is uneven; different The layout of the inlet flue affects the distribution of the flue gas flow in the furnace and the distribution characteristics of the particle concentration in the inlet flue. The layout of multiple outlets in the furnace has an impact on the flue gas flow and particle distribution in the furnace; This uneven distribution also exists.

Restricted by the overall layout of the circulating fluidized bed boiler, the inlet flue of the cyclone separator is relatively short, which belongs to the short inlet flue, and the degree of acceleration of the particles in the inlet flue is very limited, and the particle is in the vertical section of the inlet flue. The distribution characteristics directly affect the separation efficiency of the cyclone separator. The performance of the short inlet flue cyclone separator is related to the arrangement of the inlet flue, that is, the position of the furnace outlet and the angle of the inlet flue relative to the furnace. The importance of this relationship is even more pronounced and becomes complicated when a furnace of large size is connected in parallel with multiple cyclones.

For the above problems, one of the disclosed solutions is to install deflectors at the inlet to improve the impact on the performance of the cyclone separator, but to set guide vanes in the outlet with a height of 6 meters and a width of 4 meters. It is difficult to realize; the second disclosed solution is to set a vertical partition wall in the furnace to divide the space of the furnace, so as to avoid the influence of the layout of the furnace outlet on the symmetry of the flue gas flow in the furnace, but this structure destroys The large-scale flue gas mixing in the furnace is eliminated, and the problems of anti-wear and suspension of the partition wall are very difficult to solve; the third disclosed solution is to arrange an even number of cyclone separators on each side of the furnace. For fluidized bed boilers, four cyclone separators need to be arranged on the left and right side walls of the furnace, but the horizontal space occupied by the four cyclone separators arranged side by side greatly exceeds the horizontal space provided by the width of the furnace. The method of cyclone separator diameter solves the layout problem, but the performance of the cyclone separator will be greatly reduced.

Utility model content

The purpose of this utility model is to overcome the shortcomings of the prior art and provide a connection between the cyclone separator and the furnace of a large circulating fluidized bed boiler, which is used for the juxtaposition of six cyclone separators of a large circulating fluidized bed boiler The method makes the flow distribution of the flue gas in the furnace uniform, and the flue gas flow of the six cyclone separators is evenly distributed, and the particle concentration distribution on the vertical section of the inlet flue of the six cyclone separators is reasonable, ensuring that the six cyclones are separated performance is consistent.

For achieving the above object, the technical solution of the utility model is:

The connection between the cyclone separator and the furnace of a large-scale circulating fluidized bed boiler is that the furnace is connected with six cyclone separators; each cyclone separator is composed of an inlet flue and a cylinder; the furnace (10) The cross-section (BKQN) is rectangular, and the upper part of the wider two side walls is respectively provided with three flue gas outlets. are connected to the inlet flue of a cyclone separator; where,

a) The cylinder structure and size of the six cyclone separators are the same;

b) The two sets of cyclones located on the two side walls, the cross-section of the inlet flue of each set of three cyclones, and the cross-section of the inlet flue of the other set of three cyclones, about the central point of the furnace (R) Centrosymmetric;

c) There are two sets of cyclone separators located on the two side walls, and the cross-sections of the inlet flues of the two outermost cyclone separators in each set are axisymmetric with respect to the hearth centerline (JP).

For each set of outermost cyclone separators, the angle (a) formed by the outer side (AB) of the inlet flue cross-section (ABDC) and the two side walls (BK, QN) of the furnace connected to it is 90°~ 110°; the angle (b) formed by the outer edge (AB) and the inner edge (CD) of the inlet flue cross section (ABDC) is 0-30°, where the angle (b) is 0° means The outer side (AB) and the inner side (CD) are parallel to each other.

The angle (c) formed by the outer side (FE) of the cross-section (FEHG) of the inlet flue of the cyclone separator in the middle of each group and the two walls (BK, QN) of the furnace connected to it is compared with the angle (a ) small 0 ~ 10 °.

Said angle (c) ≧90°.

The position of the intersection (E) of the outer side (FE) of the inlet flue cross section (FEHG) of the cyclone separator in the middle of each group and the connected furnace side walls (BK, QN) satisfies BE=BK/ 3±10%.

The angle (d) ≥ angle (b) formed by the outer side (FE) and the inner side (GH) of the cross-section (FEHG) of the inlet flue of the cyclone separators in the middle of each group.

The relationship between the inlet flue opening width (EH) of the cyclone separator in the middle of each group and the inlet flue opening width (BD) of the outermost cyclone separator in each group is: EH=BD±2%.

The connection between the cyclone separator and the furnace of the large-scale circulating fluidized bed boiler provided by the utility model can make the flow distribution of the flue gas in the furnace by reasonably setting the position of the outlet of the furnace flue gas and the shape of the inlet flue of the cyclone separator. Uniformity, and the flue gas flow of the six cyclone separators is evenly distributed, and the particle concentration distribution on the vertical section of the inlet flue is reasonable, which ensures that the performance of each cyclone separator is consistent.

Description of drawings

Fig. 1 is the top view schematic diagram of the connection embodiment 1 between the cyclone separator and the furnace of the large circulating fluidized bed boiler of the present invention;

Fig. 2 is the top view schematic diagram of the connection embodiment 2 between the cyclone separator and the furnace of the large circulating fluidized bed boiler of the present invention;

Fig. 3 is a schematic top view of Embodiment 3 of the connection between the cyclone separator and the furnace of the large circulating fluidized bed boiler of the present invention.

Detailed ways

Referring to Figures 1, 2, and 3, the connection between the cyclone separator and the furnace of the large-scale circulating fluidized bed boiler of the present invention is to arrange the cyclone separators 1, 3, 4, and 6 at the four corners of the furnace cross section BKQN respectively. The position of these four cyclone separators is symmetrical to the center point R of the furnace, which can fill the four corners of the furnace with flue gas to the greatest extent, avoid the phenomenon of flue gas stagnation or swirl at the corners, and make the cyclone separator 1, The flue gas flow rates of 3, 4, and 6 are basically the same.

The angle a formed by the outer side AB of the inlet flue cross section ABDC of the cyclone separator 1 and the side BK of the furnace cross section BKQN connected to it is 90-110°; the inlet flue cross section ABDC of the cyclone separator 1 The angle between the outer side AB and the inner side CD is b=0～30°; since the cyclone separators 1, 3, 4, and 6 are symmetrical about the center point R of the furnace, the cyclone separators 3, 4, and The inlet flue structure of 6 is the same as that of cyclone separator 1. Through the above-mentioned angle between the inlet flue and the furnace, and the above-mentioned shape of the inlet flue, after the flue gas enters the inlet flue of the cyclone separator, the ash entrained in the flue gas is enriched toward the outer side of the inlet flue, And flow into the cyclone separator along the outer side of the inlet flue, so as to ensure that the gas-solid separation efficiency of the cyclone separator reaches a sufficiently high level.

The opening of the inlet flue connecting the cyclone separators 2 and 5 to the side wall of the furnace is not located in the middle of the side wall of the furnace, and the shape of the inlet flue is not necessarily the same as that of the other four separators. Practice has proved that if simply according to the structural size of the cyclone separator 1, the separators 2 and 5 are installed in the middle of the furnace side wall, the flue gas volume of these two cyclone separators will be significantly less than the other four, and the separation Efficiency is also significantly lower. The opening position of the inlet flue connecting the cyclone separators 2 and 5 of the utility model to the side wall of the furnace is offset to BE=BK/3±10% to the outer side of the inlet flue, so that the furnace flue gas can enter the inlet After the flue, the ash entrained by the flue gas is enriched toward the outer side, thus ensuring the separation efficiency of the two separators; at the same time, reducing the distance between the outer side FE of the inlet flue cross section and the side BK of the furnace cross section The inner angle c, so that a-c=0～10°, can prevent the furnace flue gas from directly washing the central cylinder, causing the solid particles in the flue gas to escape directly from the central cylinder in a short circuit, so as to further ensure that the separation efficiency of the cyclone separator 2 and 5 will not be reduced In addition, by changing the angle d of the inlet flue outer side and the inner side of the cyclone separator 2 and 5, make d≥b, and make EH=BD ± 2%, further guarantee to enter the cyclone separator 2 and 5 The amount of flue gas is equivalent to that of the remaining 4 separators, thus ensuring uniform flue gas flow of the six separators and ensuring the uniformity of flue gas flow on the cross-section of the furnace.

Because on the BK side of the furnace BKQN, the opening EH of the inlet flue of the intermediate cyclone separator 2 on the furnace is biased towards the BN side, which makes the flue gas near the BK side wall of the furnace tend to be biased towards the BN side. In order to correct this tendency, on the NQ side of the furnace BKQN, the opening of the inlet flue corresponding to the intermediate cyclone separator 5 on the furnace is biased towards the KQ side of the furnace, so that the cyclone separator 5 and the cyclone separator 2 are relative to the furnace BKQN The central point R of the furnace is symmetrical, so that a symmetrical and uniform flue gas flow distribution is achieved on the entire cross-section BKQN of the furnace.

In practical applications, the openings of the inlet flues of cyclone separators 1 to 6 on the furnace may be in the form of flaring, that is, the inner and/or outer sides of the cross section are broken line segments composed of two straight line segments. When the extension line of the straight section of the outer side and the inner side near the separator cylinder to the direction of the furnace, the quadrilateral enclosed by the side wall of the furnace still meets the above-mentioned characteristics of the utility model; the inlet flue of the above-mentioned separator Opening width, at this time, is the distance between the two intersection points of the extension line of the straight section of the side of the inlet flue cross-section close to the separator cylinder towards the furnace and the two intersections of the side wall of the furnace.

Below in conjunction with embodiment concrete description.

Example 1

Fig. 1 is the top plan view of the large-scale circulating fluidized bed boiler furnace and six cyclone separators in Example 1 of the utility model. In the figure, the basic outline of the furnace and cyclone separators on the top view is represented by a single line, which is the flow of flue gas. inner wall. Parameters such as the concrete structure of these walls and thickness have nothing to do with the task of the present utility model, do not represent among the figure. The rectangle BKQN represents the cross-section of the furnace surrounded by four side walls. Sometimes the four corners of the furnace may have cut corners, and the cross-section can still be approximately considered as a rectangle.

The six cyclone separators are all composed of a cylinder body and an inlet flue, and the six cyclone separators are connected to the flue gas outlet of the furnace through their respective inlet flues. The cylinder structures and dimensions of the six separators are the same.

Cyclone separators 1, 2, and 3 are arranged side by side on the BK side of the furnace in sequence, and cyclone separators 4, 5, and 6 are arranged side by side on the NQ side of the furnace in sequence, and the BK side and the NG side are the long sides of the furnace cross section; the cyclone separator On the cross-section of the inlet flue of 1, there are the outer side AB and the inner side CD of the inlet flue, and BD is the opening of the inlet flue, and is also one of the six flue gas outlets of the furnace.

The cross section of the inlet flue of cyclone separator 1, cyclone separator 2, and cyclone separator 3, and the cross section of the inlet flue of cyclone separator 4, cyclone separator 5, and cyclone separator 6, about the furnace center point R Central symmetry; the cross-sections of the inlet flues of cyclone separator 1 and cyclone separator 4, and the cross-sections of the inlet flue passages of cyclone separator 3 and cyclone separator 6 are axisymmetric about the furnace center line JP.

Taking cyclones 1 and 2 as an example, the definition of cyclone separators in the middle position on each side of the furnace is illustrated.

The structure and size of the cyclone separator 2 are basically the same as that of the cyclone separator 1, the difference is only in the inlet flue. The outer edge FE of the inlet flue FEHG of the cyclone separator 2 is located on the left side of the inner edge GH, which is the same as the relationship between the inner and outer sides of the inlet flue of the cyclone separator 1 .

The angle a formed by the outer side AB of the inlet flue cross-section ABDC of the cyclone separator 1 and the side BK of the furnace cross-section BKQN connected to it is 100°; the outer side of the inlet flue cross-section ABDC of the cyclone separator 1 The angle b formed by the side AB and the inner side CD is 10°.

The angle c formed by the outer side FE of the cross-section FEHG of the inlet flue of the cyclone separator 2 and the side BK of the furnace cross-section BKQN connected to it is 5° smaller than the angle a; the cross-section of the inlet flue of the cyclone separator 2 The position of the connection point E between the outer side FE of the FEHG and the side BK of the furnace 10 is BE=BK/3; the angle d formed by the outer side FE and the inner side GH of the cross section of the inlet flue of the cyclone separator 2 >Angle b, the relationship between the opening width EH of the inlet flue between the furnace 10 and the cyclone separator 2 and the opening width BD of the inlet flue connecting the furnace 10 and the cyclone separator 1 is EH=BD.

The relationship between the above angle and length can be adjusted appropriately within a certain range, specifically:

The angle a formed by the outer side AB of the inlet flue cross-section ABDC of the cyclone separator 1 and the side BK of the furnace cross-section BKQN connected to it can be 90-110°; the inlet flue cross-section ABDC of the cyclone separator 1 The angle b formed by the outer side AB and the inner side CD can be 0-30°, where the angle b is 0° which means that the outer side AB and the inner side CD are parallel to each other;

The angle c formed by the outer side FE of the cross-section FEHG of the inlet flue of the cyclone separator 2 and the side BK of the furnace cross-section BKQN connected to it is 0-10° smaller than the angle a; the inlet flue of the cyclone separator 2 The connection point E between the outer edge FE of the cross-section FEHG and the furnace 10 in the cross-section FEHG of the furnace is BE=BK/3±10%; The relationship between the opening width BD of the inlet flue connected to the cyclone separator 1 is EH=BD±2%.

It needs to be additionally explained that the four separators 1, 3, 4, and 6 located at the four corners of the furnace in the figure, taking the cyclone separator 1 as an example, the outer side AB of the inlet flue and the apex B of the furnace BKQN are the same point, which is just a simplification In the actual design, because of the consideration of structural processing, these two points are often not coincident.

Example 2

Fig. 2 is a top plan view of a large circulating fluidized bed boiler furnace and six cyclone separators in Example 2 of the utility model. The rectangle BKQN represents the cross-section of the furnace enclosed by four side walls.

The six cyclone separators are all composed of a cylinder body and an inlet flue, and the six cyclone separators are connected to the flue gas outlet of the furnace through their respective inlet flues. The cylinder structures and dimensions of the six separators are the same.

Cyclone separators 1, 2, and 3 are arranged side by side on the BK side of the furnace in sequence, and cyclone separators 4, 5, and 6 are arranged side by side on the NQ side of the furnace in sequence, and the BK side and the NG side are the long sides of the furnace cross section; the cyclone separator On the cross-section of the inlet flue of 1, there are the outer side AB and the inner side CD of the inlet flue, and BD is the opening of the inlet flue, and is also one of the six flue gas outlets of the furnace.

The cross section of the inlet flue of cyclone separator 1, cyclone separator 2, and cyclone separator 3, and the cross section of the inlet flue of cyclone separator 4, cyclone separator 5, and cyclone separator 6, about the furnace center point R Central symmetry; the cross-sections of the inlet flues of cyclone separator 1 and cyclone separator 4, and the cross-sections of the inlet flue passages of cyclone separator 3 and cyclone separator 6 are axisymmetric about the furnace center line JP.

Taking cyclones 1 and 2 as examples, the definition of the cyclone in the middle of each side of the furnace is illustrated.

The structure and size of the cyclone separator 2 are basically the same as that of the cyclone separator 1, the difference is only in the inlet flue. The outer FE of the inlet flue FEHG of the cyclone separator 2 is located on the left side of the inner GH, which is the same as the relationship between the inner and outer sides of the inlet flue of the cyclone separator 1 .

The angle a formed by the outer side AB of the inlet flue cross-section ABDC of the cyclone separator 1 and the side BK of the furnace cross-section BKQN connected to it is 90°; the outer side of the inlet flue cross-section ABDC of the cyclone separator 1 The angle b formed by the side AB and the inner side CD is 15°.

The angle c formed by the outer side FE of the cross-section FEHG of the inlet flue of the cyclone separator 2 and the side BK of the furnace cross-section BKQN connected to it is 0° smaller than the angle a, that is, the angle c is also 90°; cyclone separation The connection position between the inlet flue of the device 2 and the furnace 10 in the furnace cross section FEHG is BE=BK/3+10%; the outer side FE and the inner side GH of the cross section FEHG of the inlet flue of the cyclone separator Formed angle d=angle b, the relationship between the inlet flue opening width EH of the furnace 10 connected to the cyclone separator 2 and the inlet flue opening width BD of the furnace 10 connected to the cyclone separator 1 is EH=BD.

Example 3

As shown in Figure 3, the connection method between the furnace and the cyclone separator is exactly the same as that of Embodiment 2, the only difference is that the openings of the inlet flues of the cyclone separators 1 to 6 on the furnace are in the form of flaring, and the cross-section The inner edge is a polyline segment formed by two straight line segments.

The cross-section of the inlet flue of cyclone separator 1 is ABD”D’C, the outer side is AB, and the inner side is the broken line segment CD’D”, which is the extension line of the straight line segment CD’ close to the separator cylinder to the direction of the furnace It intersects with the furnace side wall BK at point D, and BD is the opening width of the inlet flue connecting the furnace 10 with the cyclone separator 1 .

The cross-section of the inlet flue of the cyclone separator 2 is FEH”H’G, the outer side is FE, the inner side is the broken line segment GH’H”, and the extension line of the straight line segment GH’ close to the separator cylinder to the direction of the furnace It intersects with the furnace side wall BK at point H, and EH is the opening width of the inlet flue that the furnace 10 is connected to the cyclone separator 2;

On the cross-section of the inlet flue of cyclone separator 1, the angle b formed by side AB and side CD' is 15°; on the cross-section of the inlet flue of cyclone separator 2, the angle b formed by side FE and side GH' d = angle b;

The relationship between the opening width EH of the inlet flue connecting the furnace 10 and the cyclone separator 2 and the opening width BD of the inlet flue connecting the furnace 10 and the cyclone separator 1 is EH=BD.

Claims (7)

1. The connection between the cyclone separators of the large circulating fluidized bed boiler and the hearth is characterized in that the hearth is connected with six cyclone separators; the cyclone separator is characterized in that each cyclone separator consists of an inlet flue and a cylinder; the cross section (BKQN) of the hearth (10) is rectangular, wherein the upper parts of two wider side walls are respectively provided with three flue gas outlets, six cyclone separators are divided into two groups and are respectively and fixedly connected to the two side walls, and each flue gas outlet is communicated with an inlet flue of one cyclone separator; wherein,

a) the cylinder structures and the sizes of the six cyclone separators are the same;

b) the cross sections of the inlet flues of the three cyclone separators in each group are centrosymmetric with the cross sections of the inlet flues of the three cyclone separators in the other group about the central point (R) of the hearth;

c) and the two groups of cyclone separators are positioned on the two side walls, and the cross sections of the inlet flues of the two outermost cyclone separators in each group are axisymmetric relative to the central line (JP) of the hearth.

2. Connection between the cyclone separators and the furnace of a large circulating fluidized bed boiler in accordance with claim 1, characterized in that the angle (a) formed by the outer side (AB) of the inlet flue cross-section (ABDC) of each outermost group of cyclone separators and the two side walls (BK, QN) of the furnace to which it is connected is 90-110 °; an included angle (b) formed by the outer side edge (AB) and the inner side edge (CD) of the inlet flue cross section (ABDC) is 0-30 degrees, wherein the angle (b) is 0 degree, and the outer side edge (AB) and the inner side edge (CD) are parallel to each other.

3. Connection between the cyclone separators and the furnace of a large circulating fluidized bed boiler in accordance with claim 1, characterized in that the angle (c) between the outer side (FE) of the cross-section (FEHG) of the inlet flue of the middle cyclone of each group and the two side walls (BK, QN) of the furnace to which it is connected is 0-10 ° smaller than the angle (a).

4. A connection between the cyclone and the furnace of a large circulating fluidized bed boiler according to claim 3, characterized in that said angle (c) is not less than 90 °.

5. Connection between the cyclone separators and the furnace of a large circulating fluidized bed boiler in accordance with claim 1, characterized in that the position of the intersection point (E) of the outer side edge (FE) of the inlet flue cross-section (FEHG) of the middle cyclone of each group and the two side walls (BK, QN) of the furnace to which it is connected satisfies BE BK/3 ± 10%.

6. Connection between the cyclone separators and the furnace of a large circulating fluidized bed boiler in accordance with claim 1, characterized in that the angle (d) ≧ angle (b) formed by the outside edge (FE) and the inside edge (GH) of the cross-section (FEHG) of the inlet flue of the middle cyclone of each group.

7. A connection between the cyclones of a large circulating fluidized bed boiler and the furnace according to claim 1, wherein the inlet flue opening width (EH) of the middle cyclone of each group is in relation to the inlet flue opening width (BD) of the outermost cyclone of each group by: EH ═ BD + 2%.

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