CN206112912U - A CFB boiler tertiary air center section of thick bamboo - Google Patents

Abstract

The utility model discloses a CFB boiler tertiary air center section of thick bamboo, it is cavity formula section of thick bamboo wall, contain center section of thick bamboo body, connect in the first bellows of exit end on center section of thick bamboo body top and connect in the entry end bellows of center section of thick bamboo body bottom, it all contains inner wall and outer wall, air feed cavity and its top for lining up from top to bottom between the two, the bottom is sealed, the introduction tuber pipe is connected to the first bellows of exit end provides one -level after -flame wind, entry end bellows inner wall is established the air guide branch pipe and is spouted wind formation whirl and mix with the flue gas, exit end second bellows are still connected to the first bellows of exit end upper end, its connection lets in the introduction tuber pipe of second grade after -flame wind and spouts the wind branch pipe to what spout wind in the flue, through to letting in the one -level in the flue, second grade after -flame wind, its with the flue gas in still uncombusted carbon granule and CO intensive mixing, the burning, promote the combustion efficiency of boiler.

Description

CFB boiler tertiary air central tube

Technical field

This utility model is related to the central tube of CFB boiler, particularly a kind of central tube for being passed through tertiary air.

Background technology

CFB boiler one of major defect compared with coal-powder boiler is that unburned carbon in flue dust is high, and some coals are even as high as 20%, because This causes boiler heat loss due to combustibles in refuse q4 to be much higher than coal-powder boiler.

First, the division of CFB boiler combustion zone.

With reference to the division of coal-powder boiler combustion zone, CFB boiler combustion zone is equally divided into into three parts：Primary zone, reburning zone, Burning-out zone, but it is different from coal-powder boiler, and three combustion zones of coal-powder boiler are respectively positioned in burner hearth, and the boundary in three areas of CFB boiler is such as Under.

Primary zone, primary zone is the whole space of burner hearth, and all fuel participate in burning, and burning wind is carried by an overfire air fan For, due to burner hearth empir-ical formulation ability it is weak, freeze profile exist into three big both sexes mass transfer mistaken ideas, i.e., in furnace depth direction " it is front, Oxygen-enriched high gray area afterwards ",（That is " oxygen-rich area "）And middle " fuel-rich anoxic zone "（That is " anoxic zone "）.

Reburning zone, to center cylinder of cyclone separator entrance, all burner hearth fuel that fly out participate in burning to furnace outlet, and burning is used Wind is provided by the remaining air of the forward and backward oxygen-enriched high gray area of burner hearth.

Burning-out zone, center cylinder of cyclone separator entrance to back-end ductwork heating surface horizontal access section, all separators without The fuel that method is separated participates in burning, and current boiler combustion wind is provided by the remaining air in reburning zone；

Expand burning-out zone, back-end ductwork heating surface horizontal access section to 687 DEG C of separating surfaces of cigarette temperature, in flue gas flammable carbon and Oxygen is contacted, and still can be burnt on this temperature.

Fuel after-flame needs enough oxygen（Condition one）, fuel mixes with the effective of oxygen（Condition two）, it is sufficiently high Reaction environment temperature（Condition three）, the burning time needed for meeting（Condition four）.

Burning-out zone above-mentioned condition two, all there is no problem for the nominal situation of condition three, then condition four.

Using the CFB boiler of cyclone separator, its burning-out zone flow of flue gas direction fundamental need is turned back for 90 ° twice, first Turned back upwards as level by central tube, secondly turned back as downward by level.Flue gas stream axial length depends mainly on boiler capacity, By taking the CFB boiler of " M " type arrangement as an example, 50MW unit CFB boiler axial length about 14m, 135MW units about 20m, 300MW units about 26 ~ 30m.Flue gas stream axial length as can use burning time divided by flue gas flow rate, compared with coal-powder boiler, CFB boiler cyclone separator is relatively low to fine grain separation efficiency, i.e., solid grain size is larger in burning-out zone flue gas stream, But it is behind primary zone, reburning zone, remaining incendivity diameter is fully little, the time required to after-flame（Or distance）Can't exceed Coal-powder boiler, it follows that whether meeting required burning time nor the main cause of problem generation.

In view of CO concentration in flue gas stream also above coal-powder boiler, therefore CFB boiler burning-out zone anoxia, it is to cause its q3, q4 Key of the loss more than coal-powder boiler.

A secondary wind total blast volume is increased, burning-out zone oxygen amount needs can not be met at present, because increasing burner hearth wind supply quantity Meanwhile, fine grain entrainment elutriation share also can increase, and gas solid chemical reaction equivalent proportion does not improve.At present, existing engineering is adopted With fly ash re-injection system, will the part coal ash loopback burner hearth that separates of boiler tail cleaner unit, but this solve only back The after-flame problem of part ash is sent, remainder can only still abandon it, and CO after-flames problem there is no solution in flue gas.

2nd, CFB boiler furnace outlet excess air coefficient is different from coal-powder boiler.

For coal-powder boiler, due to the fuel after-flame in burner hearth, therefore furnace outlet excess air coefficient, can be accurate Reflection fuel after-flame required air, and for CFB boiler, still with the presence of a large amount of combustibles in furnace outlet flue gas, identical coal, Design exports excess air coefficient from same with operation with Pulverized Fuel Boiler Furnace, it is clear that be improper.

The division according to above three combustion zone is needed, the corresponding excess air system of each area's end interfaces of CFB boiler is given Number, and how accurately to regulate and control burning-out zone end excess air coefficient, it is ensured that the fine grain after-flame of the cyclone separator that flies out, is mesh Front urgent problem.

Utility model content

The technical problem that this utility model is solved is providing a kind of CFB boiler tertiary air central tube.

The technological means that this utility model is adopted are as follows.

A kind of CFB boiler tertiary air central tube, the central tube is hollow type barrel, and it includes inner and outer wall, the two it Between be air feed cavity, the air feed cavity closes up and down, and connection on the barrel introduces airduct, and plural air-guide branch pipe is set in barrel.

The central tube is included：Central tube body, comprising inner and outer wall, therebetween the air feed for up/down perforation is empty Chamber；The bellows of the port of export first on central tube body top are connected to, it includes inner and outer wall, are therebetween upper end closed Air feed cavity, connection on outer wall introduces airduct, and on the introducing airduct blast pipe is also associated with；It is connected to central tube body bottom Arrival end bellows, it includes inner and outer wall, is therebetween the air feed cavity of lower end closed, and plural inducing QI is set in inwall Pipe.

Described each air-guide branch pipe to deviate diametric(al) setting, plural air-guide branch pipe simultaneously wind-guiding, to arrival end bellows Wind is sprayed at interior flue and forms eddy flow, the eddy flow direction is consistent with the flue gas eddy flow direction in flue.

The stacked bellows of the port of export second in the bellows of the port of export first top, the bellows of the port of export second are comprising inwall and outward Wall, is the cavity closed up and down between inside and outside wall, and connection on barrel introduces airduct, and on the introducing airduct blast pipe is also associated with, Some spray wind arms are set on inwall, to deviate diametric(al) setting, plural number spray wind arm is simultaneously to cylinder center for each spray wind arm Spray wind makes to form eddy flow in flue, and the eddy flow direction is in opposite direction with the eddy flow of air-guide branch pipe wind-guiding.

Also configure that on the bellows of the port of export second penetrate inside and outside wall and with the plural arm of inside and outside wall seal weld, the arm It is inserted into SNCR denitration agent spray gun.

The inner wall outside of the central tube body sets the outer fin of plural number, and the inner side of outer wall arranges plural inner rib plate, and this is inside and outside The longitudinally spaced arrangement of fin.

The air feed cavity bottom of the central tube body is provided with some longitudinal fins, its inside and outside side respectively with inwall, outer wall Air feed cavity bottom is divided into several ventilating ducts by connection, longitudinal fin.

The outside connection plural number of the central tube hangs uses steel corbel, and central tube is fixed on cyclone separator.

Above-mentioned each cylinder connected mode is welded using single hop or multistage group.

Having the beneficial effect that produced by this utility model.

1st, one-level, two grades of burnout degrees are arranged in CFB boiler center cylinder of cyclone separator, is allowed to and not yet after-flame in flue gas Carbon granule and CO be sufficiently mixed, burn, lift the efficiency of combustion of boiler, accurately regulation and control burning-out zone end excess air system Number.

2nd, this utility model cannot be caught using burning-out zone fuel after-flame required air, reinforcing is supplied with CFB boiler separator The fine particle caught and carbon monoxide（CO）Between mass transfer, combustion reaction time maximize, it is contemplated that fuel burn-off rate can be made The level suitable with coal-powder boiler is reached, q3 losses more than 99%, q4 loss more than 95% can be directly reduced, according to situations such as coal not Together, adding up to can improve boiler efficiency 1 ~ 3% or so, and even as high as 5%.The coal resources service life limited so as to extend the earth,.

Even if the 3, this utility model is not in the case where tertiary air machine or tertiary air machine failure stoppage in transit situation is configured, by high in flue Warm anoxic zone negative-pressure inlet, remains to provide small part burnout degree, so as to improve boiler efficiency.

4th, this utility model makes central tube, particularly central tube force part all the time in middle low temperature state, solve nothing Cooling central tube is yielding, come off problem.

5th, this utility model also provides convenient for SNCR denitrification spray gun insertion flue.

Description of the drawings

Fig. 1 is the longitudinal cross-section schematic diagram of CFB central tubes of the present utility model.

Fig. 2 is Section A-A figure in Fig. 1.

Fig. 3 is section B-B figure in Fig. 1.

Fig. 4 is C-C sectional views in Fig. 1.

Fig. 5 is D-D sectional views in Fig. 1.

Fig. 6 is E-E sectional views in Fig. 1.

Specific embodiment

This utility model protects a kind of CFB boiler tertiary air center tube device, and it is arranged at the outlet of cyclone separator 5. Central tube is hollow type barrel, and it includes inner and outer wall, is therebetween air feed cavity, and the air feed cavity is closed up and down, cylinder Connection on wall introduces airduct, and plural air-guide branch pipe is set in barrel, and barrel inner side is the flue risen for flue gas.

Typically, since current production technology is not easy to integrally cast each layer of central tube, thus it is above-mentioned by center Cylinder is divided into multilamellar and is readily transported and installs.

Central tube includes central tube body 1, is connected to first bellows of the port of export 2, Yi Jilian on the top of central tube body 1 It is connected to the arrival end bellows 4 of the bottom of central tube body 1.

Central tube body 1 with reference to shown in Fig. 1 and Fig. 4, it includes inwall 11 and outer wall 12, is therebetween up/down perforation Air feed cavity 13, flue gas circulated upwards by the exhaust gases passes of the inner side of inwall 11, and the outside of inwall 11 arranges the outer fin of plural number 111, the inner side of outer wall 12 arranges plural inner rib plate 121, the longitudinally spaced arrangement of the inside and outside fin.Central tube body as shown in Figure 5 1 D-D faces sectional view, the bottom of air feed cavity 13 is provided with some longitudinal fins 14, its inside and outside side respectively with inside and outside wall 11,12 The bottom of air feed cavity 13 is divided into several ventilating ducts 16 by connection, longitudinal fin 14.

If the Heavenly Stems and Earthly Branches that side is connected to firm fixed center cylinder are hung with steel corbel 15.

With reference to shown in Fig. 1 and Fig. 3, the first bellows of the port of export 2 include inwall 21 and outer wall 22, are therebetween upper end closed Air feed cavity 23, the inner side of inwall 21 is flue.Connection on barrel introduces airduct 25, and the outside of outer wall 22 is connected to as shown in Figure 3, It connects and opens inwards into one-level burnout degree with air feed cavity 23.Introduce airduct 25 and be provided with tertiary air machine accident blast pipe on the spot 26, a small amount of ambient air is sucked using combustion chamber draft, the blast pipe 26 is provided with check-valves 261, when tertiary air machine is normally transported During row, the valve is closed, under tertiary air machine or tertiary air machine failure stoppage in transit situation is not configured, by high in flue Warm anoxic zone negative pressure remains to provide small part burnout degree, while check-valves 261 also function to prevent from the unidirectional air intake of check-valves 261 Pyrotechnics is sprayed outside stove during detonation, it is ensured that using safety.

Above-mentioned one-level burnout degree is tertiary air, and its air quantity accounts for the 40% ~ 100% of total tertiary air quantity, and it can be according to reality The practical factors such as boiler capacity, the method for operation determine.

In actual installation, the inside and outside wall 21 of the first bellows of the port of export 2,22 bottoms and the inside and outside wall 11,12 of central tube 1 Weld on top so that upper and lower air feed cavity 13,23 is communicated, and the one-level burnout degree being passed through is conveyed downwards along the wind chamber of intercommunication.

With reference to shown in Fig. 1 and Fig. 6, above-mentioned arrival end bellows 4 include inwall 41 and outer wall 42, are therebetween lower end closed Air feed cavity 43, the inner side of inwall 41 is flue.

Some air-guide branch pipes are set in the barrel of arrival end bellows 4, as shown in fig. 6, some air-guide branch pipes 41 are located at inwall and water It is flat towards flue center, each air-guide branch pipe 44 is by the air-flow in air feed cavity 43 deviateing diametric(al) certain angle to cigarette Spray wind in road, at the flue that simultaneously wind-guiding makes in arrival end bellows 4 of plural air-guide branch pipe 44 eddy flow, the eddy flow direction and cigarette are formed Flue gas eddy flow direction in road is consistent.

During actual installation, the inside and outside wall 41 of arrival end bellows 4,42 tops and the inside and outside wall 11 of central tube 1, the weldering of 12 bottoms Connect so that upper and lower air feed cavity 13,43 is communicated, and the one-level burnout degree being passed through is transported through leading downwards along the wind chamber of intercommunication Gas branch pipe 41 sprays into flue.

I.e. 3 up/down perforations of air feed cavity 23,13,43, form the passage for being input into for one-level burnout degree and spraying wind.

The second bellows of at least one of which port of export 3 can be stacked on the first bellows of the above-mentioned port of export 2, with reference to Fig. 1 and Fig. 2, Equally comprising inwall 31 and outer wall 32, the inner side of inwall 31 is flue to the second bellows of the port of export 3, is to seal up and down between inside and outside wall The cavity 33 for closing.

Connection on the barrel of second bellows of the port of export 3 introduces airduct 35, airduct 35 is introduced as shown in Figure 2 and is arranged at outer wall On 32, it connects and opens inwards into two grades of burnout degrees with cavity 33, and tertiary air machine accident is additionally provided with the introducing airduct 35 on the spot Blast pipe 36, using combustion chamber draft a small amount of ambient air is sucked, and the blast pipe 36 is provided with check-valves 361, when tertiary air machine just Often during operation, the valve is closed, under tertiary air machine or tertiary air machine failure stoppage in transit situation is not configured, by flue Interior high temperature area negative pressure remains to provide small part burnout degree, while check-valves 361 are also functioned to from the unidirectional air intake of check-valves 361 Pyrotechnics is sprayed outside stove when preventing detonation, it is ensured that using safety.

Some spray wind arms 34 are set on the inwall 31 of second bellows of the port of export 3, each sprays wind arm 34 by cavity 33 Interior air-flow sprays wind into flue to deviate diametric(al) certain angle, and plural number spray wind arm 34 sprays wind simultaneously makes port of export bellows Eddy flow is formed at flue in 2, the eddy flow direction should be in opposite direction with the eddy flow of wind-guiding in the flue of arrival end bellows 4, makes air-flow High-temperature flue gas upwards are inversely rushed in, strengthens the contact probability between air and flue gas, strengthen mass transfer, as shown in Figure 6 is counterclockwise Clockwise direction shown in direction and Fig. 2.

Above-mentioned two grades of burnout degrees are also tertiary air, and its air quantity accounts for the 20% ~ 40% of total tertiary air quantity.

In addition, can also be configured on the inwall of the bellows of the port of export first or second according to actually used demand penetrate it is inside and outside Wall and with the plural arm 6 of inside and outside wall seal weld, the arm 6 is inserted into SNCR denitration agent spray gun.

In actual installation, above-mentioned each cylinder is welded using single hop or multistage group.

When using, one-level burnout degree is passed through from airduct 25 is introduced, selectivity is passed through SNCR denitration agent, initially enters the port of export In the air feed cavity 23 of the first bellows 2, then down through air feed cavity 43 is entered after air feed cavity 13, finally from air-guide branch pipe 44 ejections mix with flue gas in flue is burnt again.

Now according to the combustion case in flue, selectivity is passed through two grades of burnout degrees, and from airduct 35 is introduced cavity 33 is passed through, Simultaneously selectivity is passed through SNCR denitration agent, and air-flow is sprayed into from spray wind arm 34 and mixed with flue gas in flue.

When boiler normally runs, furnace outlet rear pass air pressure is negative pressure（Subatmospheric）, do not configuring tertiary air machine Or under tertiary air machine failure stoppage in transit situation, the air of elevated pressures enters the flue gas of lower pressure by check-valves.There is anon-normal Often during operating mode, such as furnace puff, flue air pressure occurs interim malleation（Superatmospheric）, check-valves are automatically switched off, and prevent cigarette Fire-fighting is come out of the stove outer.

Be above the most preferred embodiment of tertiary air central tube of the present utility model, and according to practical situation, possess it is above-mentioned in Empty formula barrel, other kinds of central tube of burnout degree etc. can be passed through, all within protection domain of the present utility model.

Claims (9)

1. a kind of CFB boiler tertiary air central tube, it is characterised in that the central tube is hollow type barrel, its include inwall and Outer wall, is therebetween air feed cavity, and the air feed cavity is closed up and down, and connection on the barrel introduces airduct, sets multiple in barrel Number air-guide branch pipe.

2. CFB boiler tertiary air central tube as claimed in claim 1, it is characterised in that the central tube is included：

Central tube body（1）, comprising inwall（11）And outer wall（12）, it is therebetween the air feed cavity of up/down perforation（13）；

It is connected to central tube body（1）The bellows of the port of export first on top（2）, it includes inwall（21）And outer wall（22）, the two Between for upper end closed air feed cavity（23）, outer wall（22）Upper connection introduces airduct（25）, the introducing airduct（25）On also connect It is connected to blast pipe（26）；

It is connected to central tube body（1）The arrival end bellows of bottom（4）, it includes inwall（41）And outer wall（42）, therebetween For the air feed cavity of lower end closed（43）, inwall（41）Inside set plural air-guide branch pipe（44）.

3. CFB boiler tertiary air central tube as claimed in claim 2, it is characterised in that described each air-guide branch pipe（44）With Deviate diametric(al) to arrange, plural air-guide branch pipe（44）While wind-guiding, to arrival end bellows（4）Wind is sprayed at interior flue and forms rotation Stream, the eddy flow direction is consistent with the flue gas eddy flow direction in flue.

4. CFB boiler tertiary air central tube as claimed in claim 3, it is characterised in that the bellows of the port of export first（2）On The stacked bellows of the port of export second in side（3）, the bellows of the port of export second（3）Comprising inwall（31）And outer wall（32）, between inside and outside wall For the cavity closed up and down（33）, connection introducing airduct on barrel（35）, the introducing airduct（35）On be also associated with blast pipe （36）, inwall（31）On set it is some spray wind arms（34）, each spray wind arm（34）Arranged with deviateing diametric(al), plural number spray wind Arm（34）Make to form eddy flow in flue to cylinder center spray wind simultaneously, the eddy flow direction and air-guide branch pipe（44）The eddy flow side of wind-guiding To contrary.

5. CFB boiler tertiary air central tube as claimed in claim 4, it is characterised in that in the bellows of the port of export second（3）It is upper to go back Configuration penetrates inside and outside wall（31、32）And with the plural arm of inside and outside wall seal weld（6）, the arm be inserted into SNCR denitration agent spray Rifle.

6. CFB boiler tertiary air central tube as claimed in claim 2, it is characterised in that the inwall of the central tube body （11）Outside sets the outer fin of plural number（111）, outer wall（12）Inner side plural inner rib plate is set（121）, between the inside and outside fin longitudinal direction Every arrangement.

7. CFB boiler tertiary air central tube as claimed in claim 6, it is characterised in that the air feed of the central tube body is empty Chamber（13）Bottom is provided with some longitudinal fins（14）, its inside and outside side respectively with inwall（11）, outer wall（12）Connection, longitudinal fin （14）By air feed cavity（13）Bottom is divided into several ventilating ducts（16）.

8. CFB boiler tertiary air central tube as claimed in claim 1, it is characterised in that the outside connection of the central tube is multiple Several are hung and use steel corbel（15）, central tube is fixed on cyclone separator.

9. the CFB boiler tertiary air central tube as described in claim 1 to 8 is arbitrary, it is characterised in that each cylinder connected mode is adopted Welded with single hop or multistage group.