CN101033848A - Flow equalizing low-resistance dust dedusting system - Google Patents

Abstract

This invention relates to the equalization-flow and low resistance dust-clearing system of coal boiler. The character is in that: including smoke channel, multi-Venturi tube and circulating reflux combiner, air-in fractate flow equispaced smoke box, dust-clearing machine. The air-in opening of the smoke channel sets equalization-flow and low resistance 90 degree elbow and the air outlet sets equalization-flow and low resistance 180 degree elbow. The multi-Venturi tube and circulating reflux combiner is set between the equalization-flow and low resistance 90 degree elbow and 180 degree elbow. The air outlet of the smoke channel connects to the air-in opening of the fractate flow equispaced smoke box of which the air outlet connects to the air-in opening of the dust-clearing machine. This invention can not only keep the uniformity of the velocity field, but also clear the vortex which can reduce the resistance value 72% and make the system function continually, steadily and reliably with the collection coefficient eta=30-50% and drag loss DeltaP<=150Pa. This invention can be widely used in kinds of coal boiler especially the dust clearance of fuel electric plant.

Description

The flow equalizing low-resistance dust pelletizing system of coal-burning boiler

Technical field

The present invention relates to the flow equalizing low-resistance dust pelletizing system of a kind of dust pelletizing system, particularly a kind of coal-burning boiler, be specially adapted to the dedusting of thermal power generation power plant.Belong to the industrial dedusting equipment technical field.

Background technology

At present, coal-fired boiler in power plant produces coal-fired ash content and is continuing to increase, and the dust concentration that enters deduster is significantly improved, and especially adopts circulating fluid bed flue gas desulfurization technique to enter deduster dust concentration before afterwards up to 600～1000g/Nm ³Accommodation well beyond conventional deduster, must increase the dust quantity that removes of pre-duster, enter deduster again after reducing dust concentration, therefore, the dedusting function of the air inlet smoke box of excavation dust pelletizing system is kept its airflow uniform distribution guarantee effect again and is seemed particularly important, but the air inlet smoke box unreasonable structure of existing dust pelletizing system, only has the airflow uniform distribution function, do not have dedusting function, and also there is following shortcoming in existing dust pelletizing system: 1, existing turning radius of curvature is 90 ° of flue dust velocity fields that the sharp turn head exists of 0, the concentration field lack of homogeneity, the vortex dust stratification, the high velocity wearing and tearing, shortcomings such as fluid resistance increase.2, existing turning radius of curvature is the shortcoming that the flue dust velocity field that exists of 180 ° of sharp turn heads of 0 and concentration lack of homogeneity, fluid resistance increase.3, in the prior art, two kinds of functors of gas pipe and circulating reflux device all branch are arranged, and cause CaCl easily ₂Bonding.

Summary of the invention

Purpose of the present invention provides a kind of flow equalizing low-resistance dust pelletizing system of coal-burning boiler, and this dust pelletizing system has the eddy current of elimination, can not produce bonding, characteristics such as drag losses is little, efficiency of dust collection height.

Purpose of the present invention can reach by following measure:

The flow equalizing low-resistance dust pelletizing system of coal-burning boiler, its design feature is: comprise flue, multiple venturi tube gas distribution and cycle stock backflow combiner, go up air inlet knuckle airflow uniform distribution smoke box and deduster; The air inlet place of flue is provided with 90 ° of sharp turn heads of flow equalizing low-resistance, the air outlet place of flue is provided with 180 ° of sharp turn heads of flow equalizing low-resistance, multiple venturi tube gas distribution and cycle stock backflow combiner are arranged between the 90 ° of sharp turn heads and 180 ° of sharp turn heads of flow equalizing low-resistance of flow equalizing low-resistance, the air outlet of flue is connected with the air inlet of last air inlet knuckle airflow uniform distribution smoke box, and the air outlet of last air inlet knuckle airflow uniform distribution smoke box is connected with the air inlet of deduster.

Purpose of the present invention can also reach by following measure:

One embodiment of the present invention are: described multiple venturi tube gas distribution and cycle stock backflow combiner comprise casing and the Venturi tube group, cycle stock inlet, built-in strength skewed slot and the cycle stock refluxing opening that are arranged in the casing; Described Venturi tube group is by 2 ⁿProp up the square Venturi tube of band circular choke tube and form, described Venturi tube group constitutes the gas pipe of recirculating fluidized bed; The cycle stock inlet is arranged on case side originally, and the cycle stock refluxing opening is communicated with an import of Venturi tube, and described cycle stock inlet is by built-in strength skewed slot communication loop material refluxing opening, formation cycle stock return channel.

One embodiment of the present invention are: each bar Venturi tube of described Venturi tube group is made up of contraction section, trunnion, diffuser; The inlet of contraction section is the same with the outlet of diffuser to be f=a * b; General a=b, the diameter of circular trunnion is d, the cross section $f_h=\frac{n}{4}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="A20061012408300101.png,A20061012408300111.png"\; state="\{\{state\}\}">d</figure-callout>}}^2;$ The contraction section side of being becomes the circular cone stage body, and angle of throat can be α ₁=60 °～120 °, length $l$ $1=\frac{(a-b)}{2}/\mathrm{tg}{\mathrm{\&alpha;}}_1;$ Diffuser is circle change side back taper stage body, angle of flare α ₃=14 °～25 °, length $l_{}$ ${}_3=\frac{(a-b)}{2}/\mathrm{tg}{\mathrm{\&alpha;}}_3;$ It is f=(4～10) f that square-round section closes _h, the long l of trunnion _h=(0.5～0.30) d; Single Venturi tube length overall H=l ₁+ l ₂+ l ₃

One embodiment of the present invention are: described airflow uniform distribution smoke box is last air inlet knuckle airflow uniform distribution smoke box, and it is made of last air inlet knuckle smoke box, flap guide plate group, knuckle plate group, porous airflow-distribution board and underlying ash bucket; Flap guide plate group is arranged on the air inlet place of air inlet knuckle smoke box, and flap guide plate group is by forming as if ten blocks of flaps; Knuckle plate group is provided with the air outlet inboard of smoke box, and knuckle plate group is made up of several equally distributed knuckle plates; The porous airflow-distribution board is arranged on the air outlet outside of smoke box.

One embodiment of the present invention are: the described end plate of going up air inlet knuckle smoke box is set to vertical section H1, middle tilted plate section H2, and the shape of following vertical section H3, middle tilted plate section H2 and vertical direction angle α=10 °～30 °; According to the wide L of air inlet width B, top board, the wide S of lower port of air inlet knuckle smoke box on the scene and the situation of deduster electric field height H, the ratio that H1, H2, H3 are three sections can be done suitable adjustment, but should guarantee σ≤0.20; The quantity n of the flap of described flap guide plate group is determined by relational expression B=b (n+1), high hn=360～the 720mm of flap vertical section, flap hypotenuse length is 450～900mm, and the angle β between flap vertical section and the hypotenuse is determined by relational expression (180-β)=arctg (B/H); The knuckle plate quantity m of described knuckle plate group can be determined by H0=(m+1) l, l=500～800mm, be 90 ° of knuckles between the long limit of described knuckle plate and the minor face, long limit l0=(0.5～0.7) l, minor face l1=(0.25～0.35) l, long limit of knuckle plate and horizontal line angle theta=50 °～70 °.

One embodiment of the present invention are: the spacing b=300～600mm between the adjacent bifoldable plate of the flap guide plate group of described airflow uniform distribution smoke box; Spacing l=500～800mm between the adjacent two knuckle plates of knuckle plate group.

One embodiment of the present invention are: aforesaid deduster can be made of terraced frid deduster or terraced frid electric cleaner or sack cleaner, described deduster can be built in the casing of airflow uniform distribution smoke box, can be between knuckle plate group and porous airflow-distribution board; Described terraced frid deduster is made of the terraced frid that 2～3 rows are the stagger arrangement layout; Perhaps described terraced frid electric cleaner can be arranged the terraced frid, discharge electrode and the power circuit that are the stagger arrangement layout by 2～3 and constitute, and the voltage output end of power circuit connects discharge electrode, and power circuit is connected terraced frid, constitutes dust collector pole with earth terminal; Described terraced frid very disposes, constitutes an electric precipitation unit one to one in pairs with discharge.

One embodiment of the present invention are: the windward side of described terraced frid dull and stereotyped A=100～200mm, two hypotenuse F=(0.3～1.1) A, hypotenuse and air-flow incident angle α=15 °～45 °, the semi arch of hypotenuse end is prevented window catch R=(0.05～0.1) A, along the minimum spacing C between the terraced frid of adjacent two rows of airflow direction, centre-to-centre spacing S1 with the terraced frid of two row among the row, perpendicular to the minimum spacing B1 between the terraced frid of airflow direction two row, interval S 2 between the discharge electrode of two misarrangements row, the spacing between the A plate of Electrical Discharge Machine and terraced frid is D; Percent opening B1/S1=0.3～0.5 of described terraced frid electric cleaner, compression ratio C/B1=0.5.

One embodiment of the present invention are: 90 ° of sharp turn heads of described flow equalizing low-resistance comprise 90 ° of sharp turn heads and ash bucket, and ash bucket is positioned at the lower end of sharp turn head; Be arranged in the arc curvedly in the curved or formula that is inclined upwardly with curved in the right angle of 90 ° of sharp turn heads, the import department of described 90 ° of sharp turn heads is provided with the guide plate group that is downward-sloping, and this guide plate group is made up of some blocks of oblique planar guide plates; The exit of sharp turn head is provided with the cowling panel group that is downward-sloping layout, and described cowling panel is formed by the rectification of some vertical direction is dull and stereotyped.

One embodiment of the present invention are: 180 ° of sharp turn heads of described flow equalizing low-resistance comprise 180 ° of sharp turn heads, water droplet body shape dividing plate, cowling panel group, guide plate group; The air inlet of 180 ° of sharp turn heads and gas outlet section respectively are provided with one group of cowling panel group, and described cowling panel group is made up of five cowling panels; Be provided with dividing plate in the middle of the air inlet of 180 ° of sharp turn heads and the cross section, gas outlet; Two clinodiagonal places of 180 ° of sharp turn heads respectively are provided with one group of circular-arc guide plate group, and described guide plate group is made up of five circular arc guide plates; The top corner place of described 180 ° of sharp turn heads is arranged to inclined-plane or cambered surface.

One embodiment of the present invention are: inside turn place of described 90 ° of sharp turn heads is that interior bent arc is turned, and the radius of circular arc is r _nTwo drift angle places of described 180 ° of sharp turn heads can respectively be provided with hang plate at 45, form 135 ° obtuse angle drift angle.

The invention has the beneficial effects as follows:

1, the present invention is owing to right angle inside turn place with 90 ° of sharp turn heads changes curved or 135 ° of dull and stereotyped turnings in the circular arc into, and adopt inlet guide plate group and outlet cowling panel group to mate, it with whole burst turning radius of curvature 0 plume, be divided into (n+1) strand parallel little plume by n piece guide plate, therefore, the flue gas that enters 90 ° of sharp turn heads both can keep velocity field uniformity σ o=(1.2～1.5) σ i, eliminated eddy current again, made resistance coefficient reduce 72%.Because two drift angle places of 180 ° of sharp turn heads are provided with oblique top plate at 45 or arc turning, and the place is provided with dividing plate in the middle of inlet, outlet, make the interior rate of curving radius of 180 ° of elbows be increased to r0=b/2 by 0, outer turning drift angle becomes two obtuse angles by 90 ° of dead angles; And trapezoidal dull and stereotyped cowling panel group being set at air inlet and gas outlet section, the clinodiagonal place is provided with arc plate guide plate group, is 0 plume half-turn with the turning radius of curvature, and is divided into (n+1) strand parallel little plume, realizes big radius of curvature transfer.Essence is to be 0 plume half-turn with whole burst turning radius of curvature, and is divided into (n+1) strand parallel little plume, realizes that big radius of curvature turning angle greater than 120 ° parallel transfer, both can keep velocity field uniformity σ ₀=(1.2～1.5) σ _i, can eliminate eddy current again, reduce resistance coefficient.Multiple venturi tube gas distribution and cycle stock backflow combiner between 90 ° of sharp turn heads and 180 ° of sharp turn heads, the Venturi tube diffuser enters the mouth that this place turbulent flow is the strongest, static pressure is minimum because cycle stock refluxing opening of the present invention is positioned at, the caloic exchange strongly, but the cigarette temperature does not reduce, generally＞120 °, Ca (OH) ₂With HCl chemical reaction alkalize chlorination calcification (CaCl ₂Ca (OH) ₂H ₂O) non-caked, therefore, can as prior art in the past, not generate caking property, the very strong CaCl of hygroscopicity down at 60～80 ℃ ₂Thereby make in fluid bed and the follow-up flue cleaning equipment and can not produce bonding, the assurance system is continuous, stable, reliability service.

2, the airflow uniform distribution smoke box of the used last air inlet knuckle of the present invention is provided with flap guide plate group by the air inlet section at last air inlet knuckle smoke box, and whole strand of flue gas tentatively is divided into (n+1) strand along H ₀Highly equally distributed plume; Inner chamber at smoke box is provided with the knuckle plate, and (n+1) strand flue gas is moving around the knuckle plate current, and leading downward flue gas changes leading level direction slightly down into and flows; Streaming generation centrifugal force removes the thick grit of part; Owing to terraced frid deduster or terraced frid electric cleaner are set at the airflow uniform distribution smoke box air outlet place of last air inlet knuckle, " labyrinth " runner that forms when utilizing the terraced frid stagger arrangement of 2～3 rows to arrange, accept leading level in upstream and flue gas slightly down, grit is separated and concentrated to falling into ash bucket under bigger centrifugal action along the vortex at the terraced frid windward side and the back side; Flue gas by way of repeatedly break-in, turn back, preliminary homogenising after the blending can guarantee to realize velocity field root-mean-square value σ≤0.20 through the porous airflow-distribution board again.Flue dust is subjected to inertia force, effects such as centrifugal force and gravitational settling, and efficiency of dust collection reaches η=30～50%, drag losses Δ P≤150Pa.

3, the present invention is widely used in the occasion dedusting of all kinds of thermal power plants and other use coal-burning boilers, has good social benefit and economic benefit.

Description of drawings

Fig. 1 is the structural representation of the specific embodiment of the invention 1.

Fig. 2 is the structural representation of 90 ° of sharp turn heads of flow equalizing low-resistance among Fig. 1.

Fig. 3 is the structural representation of 180 ° of sharp turn heads of flow equalizing low-resistance among Fig. 1.

Fig. 4 is a structural representation of going up the airflow uniform distribution smoke box of air inlet knuckle and terraced frid dedusting among Fig. 1.

Fig. 5 is the structural representation of multiple venturi tube gas distribution and cycle stock backflow combiner among Fig. 1.

Fig. 6 is a structural representation of going up the airflow uniform distribution smoke box of air inlet knuckle and terraced frid electric precipitation in the specific embodiment of the invention 2.

Fig. 7 is the structural representation of electric cleaner among Fig. 6.

The specific embodiment

Specific embodiment 1:

Fig. 1, Fig. 2, Fig. 3, Fig. 4 and Fig. 5 constitute specific embodiments of the invention 1.

With reference to Fig. 1, present embodiment comprises flue 1, multiple venturi tube gas distribution and cycle stock backflow combiner 2, goes up air inlet knuckle airflow uniform distribution smoke box 3 and deduster 4; The air inlet place of described flue 1 is provided with 90 ° of sharp turns 5 of flow equalizing low-resistance, the air outlet place of flue 1 is provided with 180 ° of sharp turns of flow equalizing low-resistance 6, multiple venturi tube gas distribution and cycle stock backflow combiner 2 are arranged between 90 ° of sharp turns 5 of flow equalizing low-resistance and 180 ° of sharp turns of flow equalizing low-resistance 6, the air outlet of flue 1 is connected with the air inlet of last air inlet knuckle airflow uniform distribution smoke box 3, and the air outlet of last air inlet knuckle airflow uniform distribution smoke box 3 is connected with the air inlet of deduster 4.

With reference to Fig. 2, the sharp turn of described flow equalizing low-resistance 5 comprises 90 ° of sharp turns 51 and ash bucket 54, and ash bucket 54 is positioned at the lower end at sharp turn 51; Be arranged to curved in the arc (or curved in the formula that is inclined upwardly) with curved in the right angle at 90 ° of sharp turns 51, the import department at described 90 ° of sharp turns 51 (smuggling is H) is provided with the guide plate group 52 that is downward-sloping, and this guide plate group 52 is made up of some blocks of oblique planar guide plates 55; The exit at sharp turn 51 (smuggling is B) is provided with the cowling panel group 53 that is downward-sloping layout, and described cowling panel 53 is formed by the rectification of some vertical direction is dull and stereotyped; Inside turn place of described sharp turn head is that interior bent arc is turned, and the radius of circular arc is r _n=350mm.

With reference to Fig. 3,180 ° of sharp turns of described flow equalizing low-resistance 6 comprise 180 ° of sharp turns 61, water droplet body shape dividing plate 62, cowling panel group 63, guide plate group 64; The air inlet 67 and gas outlet 68 sections at 180 ° of sharp turns 61 respectively are provided with one group of cowling panel group 63, and described cowling panel group 63 is made up of five cowling panels 65; Be provided with dividing plate 62 in the middle of the air inlet 67 at 180 ° of sharp turns 61 and the cross section, gas outlet 67 (width is B); The two clinodiagonal places at 180 ° of sharp turns 61 respectively are provided with one group of circular-arc guide plate group 64, and described guide plate group 64 is made up of five circular arc guide plates 66; The top corner place of described 180 ° of sharp turn heads is arranged to inclined-plane or cambered surface; Two drift angle places of described 180 ° of sharp turn heads can respectively be provided with hang plate at 45, form 135 ° obtuse angle drift angle.

With reference to Fig. 4, airflow uniform distribution smoke box 3 is last air inlet knuckle airflow uniform distribution smoke box, and it is made of last air inlet knuckle smoke box 31, flap guide plate group 32, knuckle plate group 33, porous airflow-distribution board 35 and underlying ash bucket 36; Flap guide plate group 32 is arranged on the air inlet place of air inlet knuckle smoke box 31, and flap guide plate group 32 is made up of some blocks of flaps 37; Knuckle plate group 33 is provided with the air outlet inboard of smoke box, and knuckle plate group 33 is made up of several equally distributed knuckle plates 34; Porous airflow-distribution board 35 is arranged on the air outlet outside of smoke box.The described end plate of going up air inlet knuckle smoke box 31 is set to vertical section H1, middle tilted plate section H2, and the shape of following vertical section H3, middle tilted plate section H2 and vertical direction angle α=10 °～30 °; According to the wide L of air inlet width B, top board, the wide S of lower port of air inlet knuckle smoke box 31 on the scene and the situation of deduster electric field height H, the ratio that H1, H2, H3 are three sections can be done suitable adjustment, but should guarantee σ≤0.20; The quantity n of the flap of described flap guide plate group is determined by relational expression B=b (n+1), high hn=360～the 720mm of flap vertical section, flap hypotenuse length is 450～900mm, and the angle β between described flap vertical section and the hypotenuse can be determined by relational expression (180-β)=arctg (B/H); The knuckle plate quantity m of described knuckle plate group can be determined by H0=(m+1) l, l=500～800mm, be 90 ° of knuckles between the long limit of described knuckle plate and the minor face, long limit l0=(0.5～0.7) l, minor face l1=(0.25～0.35) l, long limit of knuckle plate and horizontal line angle theta=50 °～70 °.H1, H2, three sections additions of H3 equal H.

Spacing b=300～600mm between the adjacent bifoldable plate 37 of the flap guide plate group 32 of described airflow uniform distribution smoke box 3; Spacing l=500～800mm between the adjacent two knuckle plates of knuckle plate group 33.

The deduster 4 that is positioned at airflow uniform distribution smoke box 3 exits is made of terraced frid deduster, and described deduster is between knuckle plate group 33 and porous airflow-distribution board 35; The terraced frid 41 that is the stagger arrangement layout by 2～3 rows constitutes.The windward side of described terraced frid 41 dull and stereotyped A=100～200mm, two hypotenuse F=(0.3～1.1) A, hypotenuse and air-flow incident angle α=15 °～45 °, the semi arch of hypotenuse end is prevented window catch R=(0.05～0.1) A, along the minimum spacing C between the terraced frid of adjacent two rows of airflow direction, centre-to-centre spacing S1 with the terraced frid 41 of two row among the row, perpendicular to the minimum spacing B1 between the terraced frid of airflow direction two row, interval S 2 between the discharge electrode 42 of two misarrangements row, the spacing between the A plate of Electrical Discharge Machine 42 and terraced frid 41 is D; Percent opening B1/S1=0.3～0.5 of described terraced frid electric cleaner 4, compression ratio C/B1=0.5.

With reference to Fig. 5, described multiple venturi tube gas distribution and cycle stock backflow combiner 2 comprise casing 21 and the Venturi tube group 22 that is arranged in the casing 21; Cycle stock inlet 23, built-in strength skewed slot 24 and cycle stock refluxing opening 25; Described Venturi tube group 22 is made up of the square Venturi tube that 2n props up the band circular choke tube, and described Venturi tube group constitutes the gas pipe of recirculating fluidized bed; These 21 sides of case are provided with cycle stock inlet 23, and the import department of Venturi tube is provided with cycle stock refluxing opening 25, and described cycle stock inlet 23 is by built-in strength skewed slot 24 communication loop material refluxing openings 25, formation cycle stock return channel.N=1～4 wherein.

Specific embodiment 2:

With reference to Fig. 6 and Fig. 7, the characteristics of this specific embodiment 2 are: the deduster 4 that is positioned at airflow uniform distribution smoke box 3 exits is made of terraced frid electric cleaner, described electric cleaner is made of terraced frid 41, discharge electrode 42 and the power circuit 43 that 2～3 rows are the stagger arrangement layout, the voltage output end of power circuit 43 connects discharge electrode 42, and power circuit is connected terraced frid 41, constitutes dust collector pole with earth terminal; Described terraced frid 41 and discharge electrode 42 are for disposing, constitute an electric precipitation unit one to one in pairs.All the other are identical with specific embodiment 1.

Specific embodiment 3:

The characteristics of this specific embodiment 3 are: described deduster 4 is sack cleaner, and all the other are identical with concrete fact Example 1.

Claims (10)

1, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler is characterized in that: comprise flue (1), multiple venturi tube gas distribution and cycle stock backflow combiner (2), go up air inlet knuckle airflow uniform distribution smoke box (3) and deduster (4); The air inlet place of flue (1) is provided with 90 ° of sharp turn heads (5) of flow equalizing low-resistance, the air outlet place of flue (1) is provided with 180 ° of sharp turn heads of flow equalizing low-resistance (6), multiple venturi tube gas distribution and cycle stock backflow combiner (2) are arranged between the 90 ° of sharp turn heads (5) and 180 ° of sharp turn heads of flow equalizing low-resistance (6) of flow equalizing low-resistance, the air outlet of flue (1) is connected with the air inlet of last air inlet knuckle airflow uniform distribution smoke box (3), and the air outlet of last air inlet knuckle airflow uniform distribution smoke box (3) is connected with the air inlet of deduster (4).

2, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 1 is characterized in that: described multiple venturi tube gas distribution and cycle stock backflow combiner (2) comprise casing (21) and are arranged on Venturi tube group (22) in the casing (21), cycle stock inlet (23), built-in strength skewed slot (24) and cycle stock refluxing opening (25); Described Venturi tube group (22) is by 2 ⁿProp up the square Venturi tube of band circular choke tube and form, described Venturi tube group constitutes the gas pipe of recirculating fluidized bed; Cycle stock inlet (23) is arranged on the side of case these (21), cycle stock refluxing opening (25) is communicated with an import of Venturi tube, and described cycle stock inlet (23) is by built-in strength skewed slot (24) communication loop material refluxing opening (25), formation cycle stock return channel.

3, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 2 is characterized in that: each bar Venturi tube of described Venturi tube group is made up of contraction section, trunnion, diffuser; The inlet of contraction section is the same with the outlet of diffuser to be f=a * b; General a=b, the diameter of circular trunnion is d, the cross section $f_h=\frac{n}{4}{d}^2;$ The contraction section side of being becomes the circular cone stage body, and angle of throat can be α ₁=60 °～120 °, length $l1=\frac{(a-b)}{2}/{\mathrm{tg\&alpha;}}_1;$ Diffuser is circle change side back taper stage body, angle of flare α ₃=14 °～25 °, length $l_3=\frac{(a-b)}{2}/{\mathrm{tg\&alpha;}}_3;$ It is f=(4～10) f that square-round section closes _h, the long l of trunnion _h=(0.5～0.30) d; Single Venturi tube length overall H=l ₁+ l ₂+ l ₃

4, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 1, it is characterized in that: described airflow uniform distribution smoke box (3) is last air inlet knuckle airflow uniform distribution smoke box, and it is made of last air inlet knuckle smoke box (31), flap guide plate group (32), knuckle plate group (33), porous airflow-distribution board (35) and underlying ash bucket (36); Flap guide plate group (32) is arranged on the air inlet place of air inlet knuckle smoke box (31), and flap guide plate group (32) is made up of some blocks of flaps (37); Knuckle plate group (33) is provided with the air outlet inboard of smoke box, and knuckle plate group (33) is made up of several equally distributed knuckle plates (34); Porous airflow-distribution board (35) is arranged on the air outlet outside of smoke box.

5, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 4, it is characterized in that: the described end plate of going up air inlet knuckle smoke box (31) is set to vertical section H1, middle tilted plate section H2, the shape of following vertical section H3, middle tilted plate section H2 and vertical direction angle α=10 °～30 °; The quantity n of flap guide plate group flap is determined that by relational expression B=b (n+1) the angle β between flap vertical section and the hypotenuse is determined by relational expression (180-β)=arctg (B/H); High hn=360～the 720mm of flap vertical section, flap hypotenuse length is 450～900mm, the knuckle plate quantity m of described knuckle plate group is by H ₀=(m+1) l determines that l=500～800mm is 90 ° of knuckles between the long limit of described knuckle plate and the minor face, long limit l ₀=(0.5～0.7) l, minor face l ₁=(0.25～0.35) l, long limit of knuckle plate and horizontal line angle theta=50 °～70 °.

6, according to the flow equalizing low-resistance dust pelletizing system of claim 4 or 5 described coal-burning boilers, it is characterized in that: the spacing b=300～600mm between the adjacent bifoldable plate (37) of the flap guide plate group (32) of described airflow uniform distribution smoke box (3); Spacing l=500～800mm between the adjacent two knuckle plates of knuckle plate group 33.

7, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 4, it is characterized in that: aforesaid deduster (4) is made of terraced frid deduster or terraced frid electric cleaner or sack cleaner, described deduster (4) is built in the casing of airflow uniform distribution smoke box (3), is positioned between knuckle plate group (33) and the porous airflow-distribution board (35); Described terraced frid deduster (4) is terraced frid (41) formation that stagger arrangement is arranged by 2～3 rows; Perhaps described terraced frid electric cleaner (4) is terraced frid (41), discharge electrode (42) and power circuit (43) formation that stagger arrangement is arranged by 2～3 rows, the voltage output end of power circuit (43) connects discharge electrode (42), and power circuit is connected terraced frid (41), constitutes dust collector pole with earth terminal; Described terraced frid (41) and discharge electrode (42) are for disposing, constitute an electric precipitation unit one to one in pairs.

8, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 1 is characterized in that: 90 ° of sharp turn heads of described flow equalizing low-resistance (5) comprise 90 ° of sharp turn heads (51) and ash bucket (54), and ash bucket (54) is positioned at the lower end of sharp turn head (51); With in the right angle of 90 ° of sharp turn heads (51) curved be arranged in the arc curved in the curved or formula that is inclined upwardly, the import department of described 90 ° of sharp turn heads (51) is provided with the guide plate group (52) that is downward-sloping, and this guide plate group (52) is made up of some blocks of oblique planar guide plates (55); The exit of sharp turn head (51) is provided with the cowling panel group (53) that is downward-sloping layout, and described cowling panel (53) is formed by the rectification of some vertical direction is dull and stereotyped.

9, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 4 is characterized in that: 180 ° of sharp turn heads (6) of described flow equalizing low-resistance comprise 180 ° of sharp turn heads (61), water droplet body shape dividing plate (62), cowling panel group (63), guide plate group (64); The air inlet (67) of 180 ° of sharp turn heads (61) and gas outlet (68) section respectively are provided with one group of cowling panel group (63), and described cowling panel group (63) is made up of five cowling panels (65); Be provided with dividing plate (62) in the middle of the air inlet (67) of 180 ° of sharp turn heads (61) and the cross section, gas outlet (67); Two clinodiagonal places of 180 ° of sharp turn heads (61) respectively are provided with one group of circular-arc guide plate group (64), and described guide plate group (64) is made up of five circular arc guide plates (66); The top corner place of described 180 ° of sharp turn heads is arranged to inclined-plane or cambered surface.

10, the flow equalizing low-resistance dust pelletizing system of coal-burning boiler according to claim 1 is characterized in that: inside turn place of described 90 ° of sharp turn heads (5) is that interior bent arc is turned, and the radius of circular arc is r _nTwo drift angle places of 180 ° of sharp turn heads (6) can respectively be provided with hang plate at 45, form 135 ° obtuse angle drift angle.

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