CN204153768U - Process In A Tangential Firing and burner hearth thereof - Google Patents

Abstract

The utility model relates to a kind of burner hearth of Process In A Tangential Firing, is provided with four groups of burners in burner hearth, and four groups of burners are separately positioned on the corner location of burner hearth; Along the short transverse of burner hearth, often organize burner and comprise four groups of First air spouts, five groups of overfire air ports, compact fire air nozzle and be separated fire air nozzle, four groups of First air spouts and five groups of overfire air port intervals are arranged.The burner hearth the superiors of this Process In A Tangential Firing adopt and are separated burnout degree, and part overfire air port adopts deflection Secondary Air technology, can reduce NO _xdischarge content and can efficiency of combustion be improved.Main combustion zone, bottom under anoxic conditions, forms one deck wind film by deflection Secondary Air, thus can also prevent the generation of water-cooling wall slagging scorification and high temperature corrosion accident, be conducive to preventing water screen tube overtemperature tube burst simultaneously near wall-cooling surface.In addition, the utility model also relates to a kind of Process In A Tangential Firing containing this burner hearth.

Description

Process In A Tangential Firing and burner hearth thereof

Technical field

The utility model relates to pulverized coal firing boiler, especially relates to a kind of Process In A Tangential Firing and burner hearth thereof.

Background technology

Along with the pay attention to day by day to environmental improvement, current various countries are to nitrogen oxide (NO _x) emission control obtain more and more stricter.National environmental protection portion of China also promulgates " thermal power plant's nitrogen oxide technological policy for treatment ", clearly will advance China NO in " 12 " period with all strength _xpreventing and controlling.Current home and abroad station boiler implosion NO _xtechnology mainly contains 2 kinds: one controls to generate, and mainly changes burning of coal condition by various technological means in combustion, thus reduce NO _xgrowing amount, i.e. various low NO _xtechnology; Two is the conversions after generating, the NO mainly will generated _xremoved from flue gas by technological means, as selective catalytic reduction (SCR), SNCR method (SNCR) etc.

Traditional single flow Process In A Tangential Firing ubiquity NO in coal-fired process _xdischarge too high shortcoming, and the efficiency of combustion of fire coal also has much room for improvement.

Utility model content

Based on this, be necessary to provide one to reduce NO _xdischarge content and Process In A Tangential Firing and the burner hearth thereof of efficiency of combustion can be improved.

A burner hearth for Process In A Tangential Firing, be provided with four groups of burners, and described in four groups, burner is separately positioned on the corner location of described burner hearth in described burner hearth; Along the short transverse of described burner hearth, often organize described burner comprise set gradually from bottom to up the first overfire air port, the first First air spout, the second overfire air port, the second First air spout, the 3rd overfire air port, the 3rd First air spout, the 4th overfire air port, the 4th First air spout, the 5th overfire air port, compact fire air nozzle be separated fire air nozzle;

Wherein, described first overfire air port is spout of directly drying;

Four described second overfire air ports, four described 3rd overfire air ports, four described 4th overfire air ports, four described 5th overfire air ports, four described compact fire air nozzle and four described separation fire air nozzle of every layer form deflection secondary air system respectively.

Wherein in an embodiment, described second overfire air port, described 3rd overfire air port, described 4th overfire air port and described 5th overfire air port deflection angle are in the horizontal plane ± 15 °.

Wherein in an embodiment, described burner also comprises time wind snout and tertiary air spout on May Day, described May Day time wind snout and described tertiary air spout be successively set on from bottom to up between described 5th overfire air port and described compact fire air nozzle along the short transverse of described burner hearth.

Wherein in an embodiment, described compact fire air nozzle has two, and two described compact fire air nozzle are arranged in order setting along the short transverse of described burner hearth.

Wherein in an embodiment, described separation fire air nozzle has three, and three described separation fire air nozzle are arranged in order setting along the short transverse of described burner hearth.

Wherein in an embodiment, described separation fire air nozzle is swingable to be arranged on described burner hearth, and the swingable angle of in the vertical direction is 30 °, and on horizontal plane, swingable angle is 15 °.

Wherein in an embodiment, described separation fire air nozzle is 4000mm apart from the minimum range of described compact fire air nozzle.

Wherein in an embodiment, described burner also comprises the surrounding air spout being located at least one First air spout back-fire side.

Wherein in an embodiment, the bottom surface of described burner hearth is of a size of 14022 × 12330mm ²;

Described first overfire air port is of a size of 564 × 326mm ²;

Described first First air spout, described second First air spout, described 3rd First air spout, described 4th First air spout and described May Day, time wind snout was of a size of 564 × 644mm ²;

Described second overfire air port, described 3rd overfire air port, described 4th overfire air port and described 5th overfire air port are of a size of 564 × 548mm ²;

Described compact fire air nozzle is of a size of 564 × 326mm ²;

Described separation fire air nozzle is of a size of 564 × 326mm ².

A kind of Process In A Tangential Firing, comprises the burner hearth described in above-mentioned any embodiment.

Above-mentioned Process In A Tangential Firing and the burner hearth the superiors thereof adopt and are separated burnout degree, and part overfire air port adopts deflection Secondary Air technology, can reduce NO _xdischarge content and can efficiency of combustion be improved.Main combustion zone, bottom under anoxic conditions, forms one deck wind film by deflection Secondary Air, thus can also prevent the generation of water-cooling wall slagging scorification and high temperature corrosion accident, be conducive to preventing water screen tube overtemperature tube burst simultaneously near wall-cooling surface.

Accompanying drawing explanation

Fig. 1 is the structural representation of the burner hearth of the Process In A Tangential Firing of an embodiment;

Fig. 2 be in Fig. 1 burner hearth burner each wind snout schematic diagram is set;

Fig. 3 is the structural representation of the first First air spout in Fig. 1;

Fig. 4 is the formation schematic diagram of deflection Secondary Air.

Detailed description of the invention

For the ease of understanding the utility model, below with reference to relevant drawings, the utility model is described more fully.Preferred embodiment of the present utility model is given in accompanying drawing.But the utility model can realize in many different forms, is not limited to embodiment described herein.On the contrary, provide the object of these embodiments be make the understanding of disclosure of the present utility model more comprehensively thorough.

It should be noted that, when element is called as " being fixed on " another element, directly can there is element placed in the middle in it on another element or also.When an element is considered to " connection " another element, it can be directly connected to another element or may there is centering elements simultaneously.

Unless otherwise defined, all technology used herein and scientific terminology are identical with belonging to the implication that those skilled in the art of the present utility model understand usually.The object of the term used in description of the present utility model herein just in order to describe specific embodiment, is not intended to be restriction the utility model.Term as used herein " and/or " comprise arbitrary and all combinations of one or more relevant Listed Items.

As shown in Figure 1, the Process In A Tangential Firing of an embodiment comprises coal-grinding apparatus and burner hearth 100.This coal-grinding apparatus can adopt the RP863 type medium-speed pulverizer powder process combustion system of the cold primary air fan of malleation.The bed-plate dimension of burner hearth 100 is 14022 × 12330mm ².

Incorporated by reference to Fig. 2, in burner hearth 100, be provided with four groups of burners 200, and four groups of burners 200 are arranged on the corner location in burner hearth respectively along the short transverse of burner hearth.Four groups of burners 200 preferably adopt Horizontal burner, particularly the overfire air port of burner, can increase the thermic load of burner 200, are conducive to reducing NO _xdischarge.For reducing NO _xdischarge, four groups of burners 200 of present embodiment adopt the mode of low oxygen combustion, and the selected outlet excess air coefficient of burner hearth 100 is 1.2, and wherein, air leak rate of air curtain controls within 4%.

Often organize burner 200 comprise the first overfire air port 201, first First air spout 202, second overfire air port 203, second First air spout 204, the 3rd overfire air port 205, the 3rd First air spout 206, the 4th overfire air port 207, the 4th First air spout 208, the 5th overfire air port 209, May Day time wind snout 210, tertiary air spout 211, compact fire air nozzle 212, be separated fire air nozzle 213 and surrounding air spout (not shown).Each spout is arranged successively from bottom to up along the short transverse of burner hearth.And first to May Day, time wind snout 202,204,206,208,210 and first was arranged to the 5th overfire air port 201,203,205,207,209 interval.Tertiary air spout 211, compact fire air nozzle 212 and separation fire air nozzle 213 are arranged on time wind snout 210 on May Day respectively successively from bottom to up.

First overfire air port 201 of present embodiment is spout of directly drying, and is arranged on the bottom of burner hearth 100.First overfire air port 210 is transformed, for the integral combustion efficiency improving burner 200 through micro-oil.First overfire air port is of a size of 564 × 326mm ².

First First air spout 202, second First air spout 204, the 3rd First air spout 206, the 4th First air spout 208 and May Day, time wind snout 210 was the air-flow spout containing coal dust, preferred employing wide regulating ratio (WR) coal nozzle, first time wind snout 202 as shown in Figure 3, when coal dust flows through the entrance elbow of burner 200, major part pulverized coal particle is close to elbow outer under the influence of centrifugal force and is entered coal dust jet pipe, First air is divided into deep or light two strands by the dividing plate in coal dust jet pipe, thus improves the coal powder density of First air nozzle.One to May Day is equipped with V-type bluff body in time wind snout 202,204,206,208,210, as the V-type bluff body 2022 in Fig. 3, makes First air form stable recirculating zone in V-type bluff body front, entrainments high-temperature flue gas, play the effect stabilized the flame.First First air spout 202, second First air spout 204, the 3rd First air spout 206, the 4th First air spout 208 and May Day, the size (i.e. the area of spout, below in like manner) of time wind snout 210 was 564 × 644mm ².

In the present embodiment, under full-load conditions, the first First air spout 202, second First air spout 204, the 3rd First air spout 206 and the 4th First air spout 208 are opened, and May Day, time wind snout 210 was for subsequent use.Thus being appreciated that in other embodiments, this burner 200 optionally can not arrange time wind snout 210 on May Day yet.

As shown in Figure 4, four second overfire air ports 203 of every layer, the 3rd overfire air port 205, the 4th overfire air port 207 and the 5th overfire air port 209 form deflection secondary air system respectively, and the second overfire air port 203, the 3rd overfire air port 205, the 4th overfire air port 207 and the 5th overfire air port 209 angle of deflection are in the horizontal plane ± 15 °.The First air deflected Secondary Air air-flow of air-flow that dusts is rolled in burner hearth central authorities, forms fuel-rich regions, forms enriched air district, decrease the tendency of water-cooling wall slagging scorification and high temperature corrosion, and decrease NO near combustion zone and the ice-cold wall of top surrounding _xformation.Second overfire air port 203, the 3rd overfire air port 205, the 4th overfire air port 207 and the 5th overfire air port 209 are of a size of 564 × 548mm ², have than traditional overfire air port area and reduce, the wind speed of the first overfire air port 201 and the pressure of secondary air box of bottom can be ensured.

Often organize burner 200 and comprise two compact fire air nozzle (CCOFA) 212.Compact fire air nozzle 212 is of a size of 564 × 326mm ².

First overfire air port 201, first First air spout 202, second overfire air port 203, second First air spout 204, the 3rd overfire air port 205, the 3rd First air spout 206, the 4th overfire air port 207, the 4th First air spout 208, the 5th overfire air port 209, May Day time wind snout 210, tertiary air spout 211 and compact fire air nozzle 212 all can swing up and down and be arranged in burner hearth 100, thus conveniently can regulate reheat steam temperature.

Often organize burner 200 and comprise three separation fire air nozzle (SOFA) 213.Being separated fire air nozzle 213 is 4000mm apart from the minimum range of compact fire air nozzle 212.Adopt three layers to be separated fire air nozzle to arrange, thus under separation burnout degree not throwing condition entirely, the center absolute altitude being separated burnout degree improves, and under the condition that air channel, rear portion area is certain, the wind speed being separated burnout degree is higher, can reach and reduce NO _xthe effect of discharge.Be separated fire air nozzle 213 and be of a size of 564 × 326mm ².The separation fire air nozzle 213 of present embodiment is swingable to be arranged in burner hearth 100, and the swingable angle of in the vertical direction is 30 °, and on horizontal plane, swingable angle is 15 °.Be separated fire air nozzle 213 to be designed to have up and down and horizontal hunting function, reheater temperature can be regulated by the swing being separated fire air nozzle 213, thus burnout degree penetration depth and mixed effect can be adjusted, and it is remaining effectively to prevent burner hearth 100 from exporting excessive torsion, and effectively can control burner hearth 100 and export gas temperature windage and furnace outlet gas temperature level, reduce unburned carbon in flue dust, improve efficiency of combustion.

Surrounding air spout be located at least one First air spout (as in first to May Day time wind snout 202,204,206,208,210 at least one) back-fire side, for cooling primary air nozzle, prevent air port overheating deforming, and after breeze airflow catches fire, a small amount of Secondary Air can be supplied in time, be conducive to the development of combustion process.

For reducing NO _xdischarge, in the present embodiment, chooses the air quantity being separated fire air nozzle 213 ejection and accounts for 20% of total blast volume.The air quantity that compact fire air nozzle 212 sprays accounts for 5% ~ 10% of total blast volume.First air adopts little wind rate to design, to control to catch fire a large amount of generations of initial stage NOx, First air wind rate (i.e. the air quantity of all First air spout ejections accounts for the percentage of total blast volume) is taken as 22%, all the other are Secondary Air wind rate, wherein, Secondary Air comprises separation burnout degree, compact burnout degree, surrounding air and other Secondary Airs.

Above-mentioned Process In A Tangential Firing and burner hearth 100 the superiors thereof adopt and are separated burnout degree, and part overfire air port adopts deflection Secondary Air technology, can reduce NO _xdischarge content and can efficiency of combustion be improved.Main combustion zone, bottom under anoxic conditions, forms one deck wind film by deflection Secondary Air, thus can also prevent the generation of water-cooling wall slagging scorification and high temperature corrosion accident, be conducive to preventing water screen tube overtemperature tube burst simultaneously near wall-cooling surface.

Low NO _xcombustion retrofit experience shows, each Secondary Air deflection angle to slagging and furnace outlet gas temperature deviation effects larger.Result of study shows, when any one fixing secondary air counter-flow angle (or opposing tangential circle angle), although the direction of rotation that First air and Secondary Air preset the circle of contact is contrary, but the direction of rotation of whole gas stream in the stove is consistent, namely First air rotates with identical direction of rotation with Secondary Air in stove.When less traditional method of indicating the pronunciation of a Chinese character angle, in stove, actual diameter is less than conventional circle of contact system.When traditional method of indicating the pronunciation of a Chinese character angle is very large, in stove, diameter of actual tangent circle is larger than conventional circle of contact system.By test and numerical simulation, obtain one in order to weigh the evaluating Φ of Concentric Counter-tangential Combustion System furnace air fluidal texture, Φ is defined as the ratio of the theoretical moment of momentum of forward and reverse (the same, being forward clockwise, is counterclockwise reverse) swirling eddy:

$\mathrm{\φ}=\frac{\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\left({\mathrm{\ρ}}_i{f}_i{v}_i^2\right)\·\frac{1}{2}\sqrt{A^2+B^2}\·\mathrm{Sin}({\mathrm{\α}}_1-{\mathrm{tg}}^{-1}\frac{B}{A})}{\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\left({\mathrm{\ρ}}_j{f}_j{v}_j^2\right)\·\frac{1}{2}\sqrt{A^2+B^2}\·\mathrm{Sin}({\mathrm{tg}}^{-1}\frac{B}{A}-{\mathrm{\α}}_2)}$

In formula: the spout sum that m, n are clockwise direction and arrange in the other direction; ρ, f, v are each wind density, area of injection orifice and speed; α ₁, α ₂for arc tangent angle in the horizontal plane; A, B are furnace width and the degree of depth.

Select the optimal deflection angle of each spout, the deflection angle of each nozzle can be different, thus can ensure the change with furnace height, and in stove, the diameter change of fireball realizes best bellows chamber powder pattern.In conjunction with being separated swinging of burnout degree, then can control furnace outlet gas temperature in suitable scope, being also conducive to reducing stove inscribed circle, while realization " bellows chamber powder ", reduce the risk of boiler scaling and boiler water wall overtemperature tube burst further.

In order to verify above-mentioned low NO _xthe effect of discharge design, the present embodiment carries out boiler thermal output test before and after transformation to the Process In A Tangential Firing of a 300MW, subcritical pressure boiler.Table 1 is the major parameter of this boiler before transformation.

Table 1 Boiler Main Parameter table

Table 2 is this Process In A Tangential Firing major parameter contrast before and after transformation.

Front and back Boiler Main Parameter contrast transformed by table 2

As can be drawn from Table 2, this boiler of power plant is by after low nitrogen transformation, and effect clearly on the whole.After the transformation of too low nitrogen, when (300MW) at full capacity, boiler NO _xconcentration is by the 565mg/Nm before transforming ³be reduced to improved 295mg/Nm ³, reduction amplitude reaches 47%, and exhaust gas temperature is reduced to improved 114 DEG C by 145.8 DEG C before transforming, and reduces 31.8 DEG C.When load is 250MW, boiler NO _xconcentration is by the 539mg/Nm before transforming ³be reduced to improved 280mg/Nm ³, reduction amplitude reaches 48%, and exhaust gas temperature is reduced to improved 108.4 DEG C by 136 DEG C before transforming, and reduces 27.6 DEG C.Compare the performance test data before transformation, except fly ash combustible material under high load capacity (horizontal flue sampling) has rising, under other load, fly ash combustible material has decline to a certain degree, and before comparing transformation, boiler efficiency approximately improves about 1.3%.Furnace outlet left and right sides gas temperature windage is reduced to improved 20 ~ 80 DEG C by 100 ~ 200 DEG C before transforming, and reduction amplitude reaches 100 DEG C.

By Boiler Main Parameter contrast before and after transformation, under different load, air preheater entrance NO _xreduce obvious, boiler efficiency also improves 1.3 percentage points, thus adopts burner hearth 100 structural design scheme of above-mentioned Process In A Tangential Firing to have a significant effect.

The above embodiment only have expressed several embodiment of the present utility model, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the utility model the scope of the claims.It should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these all belong to protection domain of the present utility model.Therefore, the protection domain of the utility model patent should be as the criterion with claims.

Claims (10)

1. a burner hearth for Process In A Tangential Firing, is characterized in that, be provided with four groups of burners, and described in four groups, burner is separately positioned on the corner location of described burner hearth in described burner hearth; Along the short transverse of described burner hearth, often organize described burner comprise set gradually from bottom to up the first overfire air port, the first First air spout, the second overfire air port, the second First air spout, the 3rd overfire air port, the 3rd First air spout, the 4th overfire air port, the 4th First air spout, the 5th overfire air port, compact fire air nozzle be separated fire air nozzle;

Wherein, described first overfire air port is spout of directly drying;

Four described second overfire air ports, four described 3rd overfire air ports, four described 4th overfire air ports, four described 5th overfire air ports, four described compact fire air nozzle and four described separation fire air nozzle of every layer form deflection secondary air system respectively.

2. the burner hearth of Process In A Tangential Firing as claimed in claim 1, it is characterized in that, described second overfire air port, described 3rd overfire air port, described 4th overfire air port and described 5th overfire air port deflection angle are in the horizontal plane ± 15 °.

3. the burner hearth of Process In A Tangential Firing as claimed in claim 1, it is characterized in that, described burner also comprises time wind snout and tertiary air spout on May Day, described May Day time wind snout and described tertiary air spout be successively set on from bottom to up between described 5th overfire air port and described compact fire air nozzle along the short transverse of described burner hearth.

4. the burner hearth of Process In A Tangential Firing as claimed in claim 1, it is characterized in that, described compact fire air nozzle has two, and two described compact fire air nozzle are arranged in order setting along the short transverse of described burner hearth.

5. the burner hearth of Process In A Tangential Firing as claimed in claim 1, it is characterized in that, described separation fire air nozzle has three, and three described separation fire air nozzle are arranged in order setting along the short transverse of described burner hearth.

6. the burner hearth of Process In A Tangential Firing as claimed in claim 1, it is characterized in that, described separation fire air nozzle is swingable to be arranged on described burner hearth, and the swingable angle of in the vertical direction is 30 °, and on horizontal plane, swingable angle is 15 °.

7. the burner hearth of Process In A Tangential Firing as claimed in claim 1, it is characterized in that, described separation fire air nozzle is 4000mm apart from the minimum range of described compact fire air nozzle.

8. the burner hearth of Process In A Tangential Firing as claimed in claim 1, it is characterized in that, described burner also comprises the surrounding air spout being located at least one First air spout back-fire side.

9. the burner hearth of Process In A Tangential Firing as claimed in claim 3, it is characterized in that, the bottom surface of described burner hearth is of a size of 14022 × 12330mm ²;

Described first overfire air port is of a size of 564 × 326mm ²;

Described first First air spout, described second First air spout, described 3rd First air spout, described 4th First air spout and described May Day, time wind snout was of a size of 564 × 644mm ²;

Described second overfire air port, described 3rd overfire air port, described 4th overfire air port and described 5th overfire air port are of a size of 564 × 548mm ²;

Described compact fire air nozzle is of a size of 564 × 326mm ²;

Described separation fire air nozzle is of a size of 564 × 326mm ².

10. a Process In A Tangential Firing, is characterized in that, comprises the burner hearth according to any one of claim 1 ~ 9.