CN1018017B - Fluidized bed combustion apparatus with graded circulation - Google Patents
Fluidized bed combustion apparatus with graded circulationInfo
- Publication number
- CN1018017B CN1018017B CN 90100807 CN90100807A CN1018017B CN 1018017 B CN1018017 B CN 1018017B CN 90100807 CN90100807 CN 90100807 CN 90100807 A CN90100807 A CN 90100807A CN 1018017 B CN1018017 B CN 1018017B
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- separator
- combustion chamber
- fluidized bed
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Abstract
The present invention relates to a graded circulating fluidized bed burning device. Compared with the general circulating fluidized bed burning device which adopts a high-temperature cyclone separator, the device of the present invention adopts a proposal of circulating fluidized bed burning with two-stage separation, and thus, a two-stage high-temperature material circulating reburning system of an inertial separation chamber-the cyclone separator can be adopted, and a coarse material separation first circulating system of a high-emperature shutter and a second-stage fine material circulating reburning system of a low-temperature shutter-the cyclone separator can also be adopted.
Description
The present invention relates to coal burning boiler plant, particularly fluidized bed boiler burning device.
The present CFBC equipment of widely using, (an overview of commercial circulafing Fluidized Bed Boilers.J.Yerushalmi, Pergamon Press, 1986,97-104) normally formed by the high temperature cyclone separator of a fluidized combustion chamber and burner hearth back and the material returning device of bottom.Leave the combustion chamber high-temperature flue gas with a large amount of materials, after separator is collected, sent back to the combustion chamber by material returning device, circulation is burning again.Because the thermal capacity of material is big in the system, blending is strong, flameholding, thereby its coal adaptability is good.It can be worked near the lower temperature value 900 ℃, thereby can carry out desulfuration in furnace and handle by adding lime stone, and the discharge capacity of nitrogen oxide is also lower.Because the reaction time of material is long, turbulent flow exchanges, the efficiency of combustion height.
The high temperature cyclone separator that general CFBB adopts is a kind of simply and effectively separator, but its volume is big, Heavy Weight, and the investment cost height, radiation loss is also bigger.When the igniting debugging waits, under the situation of thermal shocking, damage easily.The flue gas stream that cyclone separator comes out flow field when entering superheater is very irregular suitable, causes the superheater thermic load seriously uneven.Along with the increase of boiler capacity, its cyclone separator is also more and more big, and separating property is also along with reduction.
This system also exists the problem of material to cyclone separator refractory lining serious wear, and is fragile because wear extent is big, and the maintenance load of boiler is big, therefore need select for use quality material to make the liner of cyclone separator; The efflorescence that stands of material itself is big in addition, causes the unburned combustible in fly ash height, and the dust-exhausting quantity of boiler smoke is big, has increased the weight of the burden of rear portion deduster.
The system that has has adopted cyclone separator has been put near the low-temperature space 450 ℃ behind the superheater of rear portion, combustion chamber, but superheater surface easily is worn, and has lost the benefit that thin material continues high-temp combustion, causes the combustible loss height.The employing that has the rectilinear L shaped discrete device or baffle plate or negative and positive watt gravity one of stopping be used to power separation member or S shape separation member, but,, have influence on internal circulating load and boiler performance so its separative efficiency is relatively poor because the particle of eminence under separating can be carried secretly by lower stream of airflow.
The formula of standing stopped separation member after the system that has had adopted the combustion chamber, and collected material is fallen into the side that is provided with the heat transfer pipe laying and paid fluid bed, and flue gas is collected fines and sent into side and pay fluid bed through cyclone separator again behind superheater, and anti-again material is gone into burner hearth.This systematic comparison is huge and complicated, and the fluidizing gas of paying fluid bed makes the separative efficiency variation of block piece.
The material that general CFBB is collected through cyclone separator all is by long tremie pipe, through material returning device, in main chamber on the air distribution plate emulsion zone return into, such structural material uses more, also easily undermines air distribution plate.
Regulation and control for the fast fluidized bed boiler, following such combustion system (EP0158033) is also arranged, its first order is without high temperature cyclone separator, and with labyrinth type U post mechanical separator, the cooling wall feed bin is arranged under it, and the L by adjustable internal circulating load cuts down the material foldback that separates is got back to the bottom, combustion chamber.The loop that continuous two groups of high temperature labyrinth type U post separators and returning charge are arranged in the system.Separate and the direct returning charge of inclined tube with cyclone separator again at boiler tail.The separative efficiency of this labyrinth type separator is unsatisfactory when low concentration, and consumes expensive heat-resistant antifriction steel amount is big, and is difficult for maximizing.Whole system has three separators, and three material-returning devices are numerous and jumbled too.
In view of the problem that exists in the above-mentioned prior art, the object of the present invention is to provide a kind of novel classification cycle fluidized-bed burner, with the wearing and tearing that alleviate recycle stock separator liner and the efflorescence of material self, improve the service behaviour of burner, prolong its service life.It is more compact to reach structure in addition, better adapts to the sudden turn of events of furnace temperature, and cost and mounting cost are reduced, and also is purpose of the present invention.
For achieving the above object, the present invention has taked following technical measures, describes in detail below in conjunction with accompanying drawing.
Fig. 1 is the CFBB schematic diagram that has the two-stage separator.
Fig. 2 is the recirculating fluidized bed schematic diagram (wherein the second level is louver separator and cyclone separator assembly) that has the two-stage separator.
Wherein
Fluidized combustion chamber 1
2a first order high thermal inertia separator
2b first order high temperature louver separator
3 material returning devices
4a second level cyclone separator
Louver separator in 4b second level low temperature shutter-cyclone separator combination trap
Cyclone separator in 4c second level low temperature shutter-cyclone separator combination trap
5 material returning devices
6 air compartments
7 economizers
8 superheaters
9 coal feeding holes
(1) is difficult to the fuel of after-flame for the boiler of Small And Medium Capacity and no-smoke nicking etc., can adopts as shown in Figure 1 structure.
First order high thermal inertia separator [2a] is installed on by fluidized bed combustion chamber [1] side, and separator [2a] bottom is material returning device [3], and material returning device [3] communicates with burner hearth, consists of first order solid circulation loop. First order high thermal inertia separator [2a] is second level cyclone separator [4a] afterwards, the dipleg of the cyclone separator material returning device [5] of ining succession, and material returning device [5] communicates with burner hearth, consists of second level solid circulation loop.
When the high-temperature flue gas that is entrained with material particles is gone into the first order high thermal inertia separator of side by the fluidized bed combustion chamber jacking, utilize inertial separation and accounted for 80% coarse granule, and be collected in hopper, return burner hearth by material returning device and burn again.And carry the second level cyclone separator that fine grain flue gas enters rear side again secretly; Though this moment flue gas the speed speed height in inertia separator because grain diameter is little, and most crude particle separates in first order separator, thereby wearing and tearing greatly reduce to cyclone, and the efflorescence of material also reduces.Thin feed separation is collected after material returning device [5] returns circulating combustion in the stove, make material keep the advantage of high temperature continuous burning.The high-temperature flue gas that leaves enters the convection heating surface at boiler rear portion again.
(2) for the boiler of medium-sized and large-scale capacity, can adopt structure as Fig. 2.
The top side that is fluidized bed combustion chamber [1] is connecting high temperature louver separator [2b], and its underpart is material returning device [3], and material returning device [3] communicates with burner hearth, constitutes first order solid circulation loop.High temperature louver separator [2b] is furnished with superheater and economizer surface afterwards.Second level cold catch pot is economizer and then, second level cold catch pot can adopt the separating member of shutter [4b] cyclone separator [4c] combination, and cyclone separator [4c] bottom is a dipleg, the dipleg material returning device [5] of ining succession, material returning device [5] communicates with burner hearth, constitutes second level solid circulation loop.
The position of burner hearth is gone in first order high thermal inertia material returning device or the returning charge of high temperature louver separator, is the dilute-phase zone that is in the burner hearth middle part, and system architecture is simplified, and equally receives the benefit of returning charge burning.
Its ash blocking grid distance between plates of first order high temperature louver separator is in the 40-200mm scope, and the angle of ash blocking grid plate and airflow direction is 20-40 °, and the air velocity of turnover ash blocking grid plate is controlled at the 10-20m/s scope.
Second level cold catch pot can adopt the fabricated structure of shutter one cyclone separator, has the flue gas of 50-90% to pass through shutter in the base approximately.Collected material returns the emulsion zone of combustion chamber.Second level separator is owing to low temperature, and equipment size is smaller, and can make of general metal material.
For large circulating fluidized bed boiler, can arrange curtain wall at roof of the furnace, also can between shutter chamber and material returning device [3], arrange the cooling heating surface.
The classification cycle fluidized bed combustion syste of this employing shutter, compact conformation, combustibility is better.
Example 1
Describe the present invention in detail in conjunction with Fig. 1:
Evaporation capacity be 35 tons/time this CFBB, use the bituminous coal of 0-13mm, fuel such as meager coal, the air distribution plate area is about 1.7 * 2.2m
2, average fluidizing velocity is about～6m/s.The main chamber sectional area is about 3.2 * 2.5m
2, the combustion chamber height overall is about 12m, is fin panel casing around the furnace wall.Carry 900 ℃ the high-temperature flue gas of being about of recycle stock secretly, enter the first order inertia separation chamber of side with the speed that is about 8m/s, its sectional area is about 2.5 * 2.5m
2, the coarse granule material is separated here, and the material particular diameter that separates is about 30-2000 μ m, and the meta particle diameter is about 200 μ m, and it is the bed of material under the inertia chamber and material returning device and sent back to main fluidization combustion chamber again.Returning charge point enters in the eminence that is about 5.0m from the air distribution plate distance.The high-temperature flue gas that leaves from inertia separation chamber side wall outlet flue enters near second level cyclone separator, its internal diameter is about 3.2m, inlet velocity is about 20m/s, the fine granular materials of carrying secretly is separated here, send back in the bed by the material returning device of cyclone separator bottom, the outlet that flue gas then is forced through a Φ 1.55m who is made by heat proof material enters the rear portion superheater, economizer and air preheater and leave boiler body.
Example 2:
Describe the present invention in detail in conjunction with Fig. 2:
Evaporation capacity be 75 tons/time, pressure is 5.3 MPas, temperature is 540 ℃ a CFBB, the high 19m of main chamber, the high 3m of bottom air distribution plate district dense bed, cloth 500 the little blast caps of having an appointment on the air distribution plate, sectional area is 2.0 * 4.0m
2, fluidizing velocity is 5.7m/s, upper furnace is of a size of 3.6 * 5.6m
2, be fin panel casing all around.Air is with each 50% primary and secondary air classification supply.The wall place has passage to make flue gas enter the louver separator chamber that the first order is separated behind furnace roof, the speed of shutter ash blocking grid turnover air-flow is～12m/s, ash grid spacing is 110mm, the wide 130mm of screen, become 30 ° of angles with incoming flow, shutter is with heat-resisting rich chromium cast iron or heat resisting steel manufacturing, and also available heat-resistant antifriction ceramic material SiC makes.The separated membrane wall of thick material through both sides falls down, and sends main chamber circulation combustion again back to by the material returning device of bottom.The high-temperature flue gas that leaves shutter by two-stage superheater and two-stage economizer after, enter second level shutter one cyclone separator combined type separator, the nearly 200-400 of its operating temperature ℃, shutter ash blocking grid spacing 60mm, the wide 70mm of plate, the import and export air-flow velocity is 18m/s, thin recycle stock is concentrated in the flue gas of 10-20%, enter the cyclone separator of two Φ 1.4m, thin feed separation is collected, the gas speed of advancing cyclone separator is 12-18m/s, and thin material is sent back to main chamber circulation combustion again through a material returning device again, and flue gas then enters behind third level economizer and the air preheater and leaves boiler.
This classification cycle fluidized-bed combustion boiler combustion system and device, an evaporation capacity be 35 tons/time boiler on obtain implementing, so far boiler totally moves nearly 3800 hours, has reached nominal output, and 10% overload capacity is arranged, boiler can steady running in the load of 50-110%, its thermal efficiency reaches 86.3%, and efficiency of combustion can reach 98%, in Ca/s≤2 o'clock, its desulfuration efficiency reaches 82%, and its NOx discharge capacity is 290ppm.This classification cycle fluidized-bed combustion boiler is compared with the chain furnace with capacity, is using many coals, and clear superiority is occupied in practical economy aspect.The performance of its desulfurization performance and low NOx drainage then is that general chain furnace and coal-powder boiler are not available.
The solid material particle and the wall of rapid movement collide, wall surface material is worn, self stands efflorescence material, test is pointed out: wear rate W except with the rerum natura that bumps against material, outside the Pass relative direction when colliding has, the particle diameter dp of the speed V of a material and material is two greatest factor during collision, and being similar to has following relation:
W∝dp
2·V
3
The increasing with particle diameter of increasing along with flow velocity, the rate increase of wearing and tearing and efflorescence is very fast, in the cyclone separator of general CFBB, the flow velocity of Dual-Phrase Distribution of Gas olid is very high, reach 18-25m/s, the particle diameter of material is also bigger, and dp can reach 3mm, and material bumps against again and again mutually and to wipe, and wearing and tearing and efflorescence are quite serious.
In order to alleviate wearing and tearing and efflorescence, Circulating Fluidized Bed by its particle diameter thickness, is classified to separated and collected, and send back to the combustion chamber circulation again combustion suit.Recycle stock granularity in the CFBB generally all between 0-3mm, and wherein about more than 80% be 80-2000 μ m than coarse granule, for this thicker particle, can be by realizing separating than being easier to by inertia separator.Thereby the present invention proposes the classification cycle fluidized bed combustion syste.Recycle stock is earlier through an inertia separation chamber that speed is lower, thicker particle is collected and is returned main chamber circulation combustion again, not the thinner particle that separates again through separative efficiency than higher second level separator, as the cyclone separator separated and collected, and returning charge circulation again.
In this classification separating cycle fluidized bed combustion syste, the particle that first order high thermal inertia separator is separated is thicker, but the movement velocity of its material particles is lower, though and the movement velocity of particle is yet high in the cyclone separator of the second level, back, but its grain diameter is smaller, most of bulky grain is by inertial separation, thereby total can significantly alleviate the wearing and tearing of cyclone and the efflorescence of material.The collection efficiency of classification cycle fluidized bed combustion syste,
η
Always=η i+(1-η i) η c
The collection efficiency of η i-first order separator
The collection efficiency of η c-second level separator
When η c → 0, η
Always=η i owing to adopted the two-stage separation, has improved separated and collected efficient, has improved circulation, has improved the after-flame degree of coal.
Claims (4)
1, a kind of burning device of circulating fluidized bed that constitutes by fluidized bed combustion chamber, separator and material returning device, separator is divided into the two-stage separator, connecting first order high thermal inertia separator at the top of combustion chamber side, the separator bottom communicates with the combustion chamber through pipeline, constitute first order solid circulation loop, be connected with second level separator after the first order inertial separation, the separator bottom communicates with the combustion chamber through conduit, constitutes solid loop, the second level; This device is characterised in that the top side of fluidized bed combustion chamber [1] is connecting first order low gas velocity high thermal inertia separator [2a], separator [2a] bottom connects material returning device [3], material returning device [3] is [1] dilute-phase zone returning charge in the combustion chamber, constitute first order solid circulation loop, and then first order high thermal inertia separator [2a] is second level high temperature cyclone separator [4a] afterwards, the dipleg of separator [4a] bottom is connecting material returning device [5], material returning device [5] emulsion zone returning charge on the air distribution plate of combustion chamber [1] constitutes second level solid circulation loop.
2, a kind of by fluidized bed combustion chamber, the burning device of circulating fluidized bed that separator and material returning device constitute, separator is divided into the two-stage separator, connecting first order high thermal inertia separator at the top of combustion chamber side, the separator bottom communicates with the combustion chamber through pipeline, constitutes first order solid circulation loop, is connected with second level separator after the first order inertial separation, the separator bottom communicates with the combustion chamber through conduit, constitutes solid loop, the second level; This device characteristic is that fluidized bed combustion chamber top side is connecting first order high temperature louver separator [2b], separator [2b] bottom is connecting material returning device [3], material returning device [3] is the dilute-phase zone returning charge of [1] air distribution plate top in the combustion chamber, constitute first order solid circulation loop, first order high temperature louver separator [2b] is furnished with superheater and economizer afterwards, then arrange second level cold catch pot, second level cold catch pot is the separator of shutter [4b] and cyclone separator [4c] combination, its cyclone separator bottom dipleg is connecting material returning device [5], material returning device [5] emulsion zone returning charge on the air distribution plate of combustion chamber [1] constitutes second level solid circulation loop.
3, by the described device of claim 2, it is characterized in that it is 40-200mm that described first order high temperature louver separator [2b] adopts the spacing of hurdle ash grid, the angle of hurdle ash screen and airflow direction is 20-40 °, and the air velocity of turnover hurdle ash screen is 10-20m/s.
4,, it is characterized in that and also can in first returning charge return passage, arrange the cooling heating surface at fluidized bed combustion chamber top layout curtain wall by claim 2 or 3 described devices.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90100807 CN1018017B (en) | 1990-02-21 | 1990-02-21 | Fluidized bed combustion apparatus with graded circulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90100807 CN1018017B (en) | 1990-02-21 | 1990-02-21 | Fluidized bed combustion apparatus with graded circulation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1054302A CN1054302A (en) | 1991-09-04 |
| CN1018017B true CN1018017B (en) | 1992-08-26 |
Family
ID=4876811
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 90100807 Expired CN1018017B (en) | 1990-02-21 | 1990-02-21 | Fluidized bed combustion apparatus with graded circulation |
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| CN (1) | CN1018017B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101890325B (en) * | 2009-05-20 | 2015-05-13 | 综合能源有限公司 | Fine solid particle recycling device and fluidized bed reactor comprising same |
| CN105797655B (en) * | 2014-12-31 | 2018-01-12 | 中国科学院工程热物理研究所 | Round-robin method for the circulation loop system of powder and for powder |
| CN112178627A (en) * | 2020-10-30 | 2021-01-05 | 北京热华能源科技有限公司 | Multi-flow circulating fluidized bed with labyrinth separator |
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1990
- 1990-02-21 CN CN 90100807 patent/CN1018017B/en not_active Expired
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| Publication number | Publication date |
|---|---|
| CN1054302A (en) | 1991-09-04 |
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