CN202613432U - High-temperature particle trap and circulating fluidized bed boiler using same - Google Patents

Abstract

The utility model discloses a high-temperature particle trap and a circulating fluidized bed boiler using the same. According to the utility model, a particle trap is designed to realize efficient high-temperature low-resistance gas-solid separation and provide an efficient low-resistance particle trapping process. According to the high-temperature particle trap, a gas-solid guide plate and long-side long channel steel compose a particle trapping mechanism; particles entering into a barrier strip enter into a particle collecting cabin at the presence of vacuum aspiration, but cannot return to a main smoke flue, so that separation efficiency can be obviously close to 100%, but running resistance is not increased obviously. The high-temperature particle trap and a circulating fluidized bed boiler using the same, disclosed by the utility model, have the advantages of realizing efficient low-resistance gas-solid separation in a high-temperature process, enabling the structure of the circulating fluidized bed boiler to be more compact and solving the problems of high running resistance and high power consumption of a cyclone separator of a traditional circulating fluidized bed boiler.

Description

The CFBB of high-temperature particle trap and use high-temperature particle trap

Technical field

The utility model belongs to high temperature gas-solid separation field, and a kind of high efficiency granule capturing process of lower resistance is provided, and the high-temperature particle that is captured gets into the localized area under the inducing of granule trap, realizes the efficient low-resistance gas solid separation process of high chilling process.The gas solid separation process that can be used for fields such as chemical industry, power, metallurgy, environmental protection.

Background technology

China is the use state of maximum in the world CFBB.2010 the end of the year China had more than 3000 with the relevant CFBB of generating, the boiler heap(ed) capacity reaches 300MW.First in China also is that the first in the world platform 600MW CFBB has begun to build, and China will become the most perfect country of CFBB.

A CFBB and conventional power generation usage boiler huge difference structurally has been many flying dust closed circuit.This cover loop neither the burning needs, the needs that neither conduct heat only are employing all means available of taking in order to improve boiler performance.If do not adopt this cover loop, CFBB is just got back to so-called bubbling fluidized bed boiler, outside aspect performances such as burning and desulfurization slightly descend, does not all have appreciable impact at aspects such as boiler capacity, the method for operation, power plant's operations.Yet this cover only provides the structure of boiler performance raising and but brings the personal electric consumption in power plant by a relatively large margin.Its reason is that the High Temperature Gas solid separation device forms very big power consumption, and this power consumption can only be born by boiler induced-draft fan.

Usually the high temperature gas solid separation of recirculating fluidized bed adopts cyclone separator.The difference of the cyclone separator of different manufacturers and research institution's design mainly is reflected in aspects such as cross sectional shape, physical dimension, the type of cooling, structural texture and construction material; In order to reach higher separative efficiency; CFBB has been eliminated so-called low-resistance such as louver separator, the labyrinth separator not high high-temperature separator of efficient simultaneously between period of expansion, almost without exception selection cyclone separator.This development course is hinting that industrial quarters accepted the technology reality of efficient high resistant.

The development course of Combustion technology of circulating fluidized shows, if can not get enough returning charges, arranges that how many heating surfaces all are difficult to obtain the boiler output of hope.Its reason is to get back to burner hearth through fly ash granule that high-temperature separator captures not only to have regulated the diabatic process that fire box temperature has also been strengthened furnace wall cooling, has significantly improved the steam production of boiler furnace.

As far as CFBB; Effectively feed back the high-temperature particle of q.s; Can guarantee that not only boiler furnace produces the saturated vapor of q.s; Also having determined the caloric receptivity of the various heating surfaces of boiler (water-cooling wall, superheater, reheater etc.) to distribute to a certain extent, is the parameter that boiler operatiopn needs strict guarantee.See that from another angle flying dust feeds back the burn-off rate that has not only improved these flying dusts itself, the boiler overall operation is also had the indirectly-acting that reduces Fuel Consumption.Therefore, guarantee that high-temperature separator efficient becomes one of key factor that boiler design person at first considers, this also possibly be that manufacturer abandons other high-temperature separators and adopts the immediate cause of cyclone separator.

Yet the efficient of cyclone separator and running resistance are a pair of born paradox.Efficiently inevitable high resistant, the high isolation resistance that brings when satisfying boiler performance become resistance maximum in the boiler smoke passage and constitute.The data that obtain at present see that the cyclone separator resistance is between 1000～2000Pa.Design like the Chinese Academy of Sciences; The cyclone separator resistance that the 200MW CFBB is selected for use is a 2kPa (Sun Yunkai; The exploitation of 600t/h Design of CFB Boiler; First theoretical the 6th nd Annual Meeting collection of service collaboration net that exchange with technological academic conference and national power industry CFB machine set technology of Chinese CFBC; 2007. the Haikou), the cyclone separator resistance that the 135MW CFBB is selected for use is 1.5kPa (Bao Shaolin, Firing Shenhua Coal system oil private station 440t/h CFB boiler design and operation; First theoretical the 6th nd Annual Meeting collection of service collaboration net, 2007. Haikou of exchanging with technological academic conference and national power industry CFB machine set technology of Chinese CFBC); Under this pressure drop, (scope of design can select 18～35m/s) to the inlet gas speed selection of cyclone separator near 18m/s～20m/s.

Xi'an hot working research institute shows that to the measurement of certain power plant 135MW CFBB generating set the air-introduced machine actual power consumption reaches 2.657kWh/t, with the gap of air-introduced machine power consumption desired value 2.049kWh/t is-1.039kWh/t.This power plant air-introduced machine power consumption accounts for 0.7% (Wang Zhiwei, CFB unit running optimization systematic research exploitation and the application of SIS system in the CFB unit, CFBB coorporative network annual meeting ppt, 2007.5 Dalian).This is to confirm that cyclone separator is in the result who uses on the CFBB under the rational prerequisite.Same measurement shows, this power plant's station service target 9.327%, and actual station service power consumption rate 12.984% causes the many 17.991g/kWh of gross coal consumption rate.Though power plant from electricity consumption what, be to guarantee boiler output, the cyclone separator running resistance can not change, so the absolute value of air-introduced machine power consumption can not change.

Cyclone separator of circulating fluidized bed boiler pressure drop at present becomes that maximum mechanism falls in pressure in the flue gas flow between 1000～2000Pa, also be the key link that causes the air-introduced machine power consumption high.Table 1 has provided the related data of some existing intermediate size CFBBs.Data show that the air-introduced machine power consumption is on thousands of kW orders of magnitude.

Table 1. CFBB air-introduced machine power consumption

Boiler capacity	Flow	Voltage rise	Power of motor	Unit platform number
					50MW	283000m 3/h	850mmH 2O	1410kW	1
135MW	2×279973m 3/h	5634Pa	1800×2kW	2
					300MW	340m 3/s	7800Pa	3600×2kW	2

See that from the boiler smoke flow process High Temperature Gas solid separator is not the requisite device of boiler, it neither the burning needs, the needs that neither conduct heat only are the mechanisms that improves boiler performance.Therefore, satisfying under the basic demand condition of boiler performance, the High Temperature Gas solid separator can be simple as much as possible, and simple result is decline of flow of flue gas resistance and the air-introduced machine power consumption decline that causes thus.

If the high-temperature separator running resistance is reduced by 1000～1500Pa; Can use the running resistance about 500Pa to accomplish the separative efficiency that cyclone separator 1500～2000Pa drag energy is realized in other words; Then the air-introduced machine pressure head can reduce greatly, and power savings is very outstanding.

Summary of the invention

The flue gas flow of CFBB is: the burner hearth High Temperature Gas solid two-phase that comes out carries out gas solid separation through cyclone separator, and the particle that is captured is got back to burner hearth through material-returning device, and flue gas is drawn into heated surface at the end of boiler by air-introduced machine.

The utility model has designed a kind of granule trap to realize effective low-resistance high temperature gas solid separation.Granule trap is made up of high temperature gas-solid separating mechanism and particle collection storehouse system.The high temperature dust flue gas that boiler hearth of circulating fluidized bed comes out carries out gas solid separation when passing through granule trap, the high-temperature particle that separates returns burner hearth through the material-returning device of boiler, and flue gas gets into heated surface at the end of boiler through behind the granule trap.Fig. 1 has provided the sketch map of the circulating fluid bed boiler structure that comprises the granule trap notion.The high-temperature flue gas that boiler hearth of circulating fluidized bed 1 burning produces carries a large amount of high-temperature particles and gets into granule trap system 3 and carry out gas solid separation, and the flue gas after the separation gets in the boiler back end ductwork 2.

Granule trap is on the basis of labyrinth separator, to form.The test efficiency of labyrinth separator can reach very high efficiency numerical value, but because ability is swept along and carried secretly to follow-up air-flow to the particle that has separated, has damaged the separation process of labyrinth separator.The researcher has carried out a large amount of pilot studys to the labyrinth separator; The labyrinth blend stop goes out various ways by the channel-section steel shape evolution, like ω-a type blend stop structure, with the ω-d blend stop structure of the blend stop structure ω-b of heat-transfer area tube construction combination or ω-c and German Essen university etc.The blend stop changes of section has been dominated the research of nearly all high low temperature labyrinth gas solid separation process.The main intention of these shape evolution seemingly separates the effect of carrying secretly of particle to upper air weakening lower stream of airflow, before getting into the particle collection space, does not receive the influence of other air-flows or sweeps along because the result of all changes attempts to produce particle.And the evolution of all these structures all to be the mechanical passage that the variation through the blend stop cross sectional shape causes a particle to fall realize.

As the granule capturing element, the granule capturing element constitutes the high temperature gas-solid separating mechanism of granule trap to the high temperature gas-solid separating mechanism of the utility model by certain structural arrangement by the channel-section steel type blend stop that has many row's deflectors.Different with forefathers is that the granule capturing part of the utility model no longer requires the blend stop cross section to change, and only is the channel-section steel of both sides lengthening in shape.Set up the passage that transports that captures the one-way movement of particle negative pressure channel formation particle in the inboard of channel-section steel.Particle just revert to the possibility of boiler smoke passage never again as long as get into this passage under suction function, promptly formed granule trap.Because granule trap need keep continuous ability to work, just be unlikely to a mechanism that induces that induces movement of particles to be set in the granule trap downstream because particle compiles the obstruction trap.The air-introduced machine of granule trap configuration causes the negative pressure running status of particle collection storehouse system, the particle that high temperature gas-solid its disengagement is got off under suction function from trend particle collection storehouse downstream advance.Low capacity air-introduced machine by a configurating filtered mechanism causes the inner negative pressure of granule trap.Before the particle that gets into granule trap will advance to the negative pressure filtration mechanism before the air-introduced machine along negative pressure.When the filter structure is descended by the particles filled granule trap negative pressure that causes, when granule trap ran out of steam, one wind blowback filter mechanism of taking from ad hoc back blowing machine or overfire air fan made its regeneration, recovered granule trap and began new round work.

Fig. 2 has provided granule trap gas-solid deflector structure figure.The gas-solid deflector is by introduction segment 1, and arc section 2 constitutes with derivation section 3.Formed the gas-solid passage between a plurality of gas-solid deflectors that vertical parallel is arranged.Form the negative pressure transport channel that particle can't return between gas-solid deflector and the channel-section steel, make the particle that become trapped in directly get into soot dust granule collection storehouse system, be i.e. the granule trap of a plurality of gas-solid deflectors of particular arrangement and channel steel shape blend stop formation.Fig. 3 has provided the concrete structure of granule trap.Gas-solid deflector 1 and long length of side channel-section steel 3 constitute the granule capturing mechanism of granule traps, form the negative pressure channel 2 of particle between the two.

Fig. 4 has provided the general layout of granule trap.The middle and lower part of particle collection storehouse system connects two particle filter mechanisms, and two particle filter mechanism back connect an air-introduced machine and a back blowing machine.Connect blower fan and particle filter mechanism through pipeline, guarantee two filter mechanisms in running order and blowback state or rest and reorganization state respectively through valve, the particle of particle collection storehouse systematic collection returns burner hearth through the standpipe of boiler returning charge mechanism.Ash-laden gas 1 from furnace outlet passes through by becoming cleaning flue gases 13 behind the certain regularly arranged granule trap 2.The separated soot dust granule that gets off gets into the soot dust granule collection storehouse 3 of granule trap.Soot dust granule and gas under 4 effects of small-power air-introduced machine in the particle collection storehouse are separated by grain bed 6, and the gas that comes out is transmitted back to boiler flue.The grain bed 6 of continuous operation a period of time can be blocked by soot dust granule, has been equipped with pulse cleaning mechanism thus.The soot dust granule that separates gets into the dipleg standpipe 8 of CFBB through flue dust hopper 7.

When grain bed 6 is full of separated soot dust granule, utilize back blowing machine that it is regenerated.Small-sized air-introduced machine 12 replaces grain bed 6 to form the granule trap system of next cycle work with grain bed 10.At this moment, grain bed 6 can be regenerated subsequent use under the back blowing machine effect.Use grain bed 6 substitute particles beds 10 again during grain bed 10 approaching being filled, form the granule trap system of continuous operation, guarantee that CFBB moves continuously.The particle filter mechanism is made up of high temperature resistance filtration material, can be that the floccule of refractory material, ceramic material, refractory fibre, metal or metal oxide constitutes.

Filter mechanism arranged beneath in the particle collection storehouse is inverted angle steel and is prevented that deposited particles is sucked on the particle filter mechanism; Shown among Fig. 49; For preventing that the particle that deposits to hopper 7 from being taken away by air-introduced machine, be provided with the grey labyrinth 9 of retaining and stop the particle that separates to get into grain bed 6 or grain bed 10.

Fig. 5 has provided the work notion of granule trap system.When using grain bed 5 work, grain bed 3 is in blowback or the state that quits work.Introductory note blower fan 7 forms negative pressure through the valve of opening 2 (valve 1 is closed) via 5 pairs of granule traps of grain bed 4.At this moment, back blowing machine 1 can carry out blowback to grain bed 3 through the valve of opening 3 (valve 4 is closed).When grain bed 5 needed blowback, back blowing machine 1 valve-off 3 was opened valve 4, and 7 of introductory note blower fans are opened valve 2 valve-offs 1, formed grain bed 3 work, grain bed 5 reproduced state.

The utlity model has following advantage:

1. can realize the efficient low-resistance operation.Granule trap has been inherited the low advantage of labyrinth separator running resistance, utilizes granule trap to ensure gas solid separation efficient.Owing on the channel steel shape blend stop, set up deflector, rigidity has been stipulated particle path.Adopted small-sized air-introduced machine under all blend stops, to cause negative pressure again, all particles that get into blend stop get into particle Ji Cang under the attraction of negative pressure, get back to the chance of going in the flue collector never again.Simultaneously, deflector has destroyed regular troughs die blend stop lower stream of airflow upper air has been separated sweeping along and carrying secretly of particle, separative efficiency can be obviously to 100% near, and running resistance does not significantly increase because of the appearance of deflector.

2. make circulating fluid bed boiler structure compact more.Because the cyclone separator cross section is circular, its minimum feature size of taking up an area of projected area is the diameter of separator.And the granule trap cross section is a rectangular configuration, can keep the size identical with boiler width in the design.Usually the most effectively isolate preceding 3～4 gear bars now, therefore, the blend stop number adopts 10, and arrange should be about 1m with the distance that occupies on the inherent flow of flue gas direction, and the cyclone separator effective diameter is exactly 7～8m easily.

3. can reduce the boiler induced-draft fan power consumption significantly.Because the decline significantly of High Temperature Gas solid separator pressure drop, boiler induced-draft fan power also will descend significantly.

Behind isolation resistance decline 1000Pa, as far as air-introduced machine, system head characteristics generation great variety, air-introduced machine is under the flow unchanged condition, and air-introduced machine institute gas-distributing motor power significantly descends.Like 50MW unit exhaust gas volumn～200000m3h-1, can select Y4-73-20D for use, air quantity 167130-320610m3h-1, pressure head 2392-3598, the gas-distributing motor 355kW of institute; 135MW unit exhaust gas volumn 280000m3h-1 can select Y4-73-20D for use, air quantity 167130-320610m3h-1, pressure head 2392-3598Pa, the gas-distributing motor 355kW of institute; (adopting 2 air-introduced machines) and corresponding boiler induced-draft fan institute gas-distributing motor energy conservation potential are at 1000～2000kW order of magnitude.

(the general industry and commerce in Hunan Province is with 0.968～1.05 yuan/kWh of the electrical network person of changing, and 1.01～1.09 yuan of net persons of changing/kWh), the electricity charge of operation of 1000kW motor year were not calculated as 7,000,000 yuan/year by 7000 hours in 1.0 yuan/kWh of present electricity price for industrial uses.

Description of drawings

Fig. 1 is the sketch map that comprises the circulating fluid bed boiler structure of granule trap notion.

Fig. 2 is a granule trap gas-solid deflector structure.

Fig. 3 is the concrete structure of granule trap.

Fig. 4 is the general layout of granule trap.

Fig. 5 is the work notion of granule trap system.

Fig. 6 is ω-a type blend stop structure

Fig. 7 is ω-b type blend stop structure

Fig. 8 is ω-c type blend stop structure

Fig. 9 is ω-d type blend stop structure

Among Fig. 1: 1. boiler furnace 2. boiler back end ductworks 3. granule trap systems

Among Fig. 2: 1. gas-solid deflector introduction segment 2. arc sections 3. are derived section

Among Fig. 3: 1. gas-solid deflector 2. negative pressure channels 3. are grown length of side channel-section steels

Among Fig. 4: 1. 4. air-introduced machines, 5. cleaning flue gases, 6. grain beds, 7. hoppers, 8. dipleg standpipes 9. in ash-laden gas 2. granule traps 3. soot dust granule collection storehouses keep off grey labyrinth 10. grain beds, 11. cleaning flue gases, 12. back blowing machines, 13. cleaning flue gases

Among Fig. 5: 1. back blowing machine 2. material returning valves 3. grain beds 4. granule traps 5. grain beds 6. back-end ductworks 7. air-introduced machines

The specific embodiment

Boiler code:

Superheat steam flow 480t/h; Superheated steam pressure 13.73MPa; 540 ℃ of superheat steam temperatures; Reheated steam flow 390.52t/h; Reheated steam import/export pressure 2.86/2.68MPa; 316/540 ℃ of reheated steam import/export temperature; 248 ℃ of feed temperatures; 167 ℃ of feed temperatures; Boiler efficiency 88.7%;

The design fuel characteristic:

Car＝37.62％；Har＝2.30％；Oar＝11.56％；Nar＝0.61％；Sar＝0.23％；War＝8.04％；Aar＝39.64％；Vdaf＝43.60％；LHV＝13390KJ/Kg；B＝111.4t/h；dmax＝9mm，d50＝0.9mm

Boiler relative dimensions: furnace width 15240mm; Furnace depth 7492mm;

Granule trap blend stop size: bottom width a=150mm, the wide b=165mm of side, laterally relative intercept s1/a=2.4, vertically relative intercept s2/a=1.67;

Blend stop arrangement mode: 6 misarrangements row;

Deflector spacing: 100mm;

The deflector physical dimension: introduction segment 108mm, derive section 65mm, arc section radius 100mm, 60 ° of circular arc angles.

Blend stop material: heat resisting cast steel

Granule trap is along flue gas flow effective length: 1500mm;

Granule trap sectional dimension: the 15240mm * 1200mm that facings the wind

Fan Selection:

Air-introduced machine: Y5-47-4C, pressure head 990-1451Pa, flow 2750-5060, motor model Y100L-2,3kW

Back blowing machine: G9-26-4A, pressure head 3407-3852Pa, flow 2198-3215, motor model Y132S1-2,5.5kW.

Claims (6)

1. one kind is used the technological CFBB of granule trap; It is characterized in that: the high temperature dust flue gas that boiler hearth of circulating fluidized bed comes out carries out gas solid separation when passing through granule trap; The high-temperature particle that separates returns burner hearth through the material-returning device of boiler, and flue gas gets into heated surface at the end of boiler through behind the granule trap.

2. the CFBB of use granule trap technology according to claim 1, it is characterized in that: granule trap is made up of high temperature gas-solid separating mechanism and particle collection storehouse system.

3. the CFBB of use granule trap technology according to claim 1 and 2 is characterized in that: the channel-section steel type blend stop that has many row's deflectors constitutes the high temperature gas-solid separating mechanism of granule trap.

4. the CFBB of use granule trap technology according to claim 1 and 2; It is characterized in that: the middle and lower part of particle collection storehouse system connects two particle filter mechanisms; Two particle filter mechanism back; Connect an air-introduced machine and a back blowing machine; Connect blower fan and particle filter mechanism through pipeline, guarantee two filter mechanisms in running order and blowback state or rest and reorganization state respectively through valve, the particle of particle collection storehouse systematic collection returns burner hearth through the standpipe of boiler returning charge mechanism.

5. the CFBB of use granule trap technology according to claim 4 is characterized in that: the filter mechanism arranged beneath in the particle collection storehouse is inverted angle steel and is prevented that deposited particles is sucked on the particle filter mechanism.

6. the CFBB of use granule trap technology according to claim 1; It is characterized in that: the air-introduced machine of granule trap configuration causes the negative pressure running status of particle collection storehouse system, the particle that high temperature gas-solid its disengagement is got off under suction function from trend particle collection storehouse downstream advance.

Images