CN85105132A - Use the improvement current divider of low load combustion device coal furnace - Google Patents

Abstract

A kind of improvement current divider that is used to use low load combustion device coal furnace.Current divider is arranged on the main delivery pipe that come out by coal pulverizer, coal and Air mixing stream is divided into two strands of streams separately, and then delivers to the single nozzles place that links to each other with this stove.Current divider comprises a retaining device, forms an adjustable gap, and has some convex shoulders, to prevent that coal is along the baffle blades slippage.

Description

Use the improvement current divider of low load combustion device coal furnace

The present invention relates to a kind of coal furnace that uses the low load combustion device, particularly a kind of selectively to the burner dispensing coal of this coal furnace and the current divider of air.

In typical coal furnace, particulate coal is to send into burner with a wind in coal pulverizer or the coal pulverizer.And to supply with secondary wind, to satisfy the sufficient air of burning needs.After the some stove, coal is lighted required energy by the radiation of flame and furnace wall and the conduction of flame for the coal that inserts provides with regard to the constantly burning owing to the local recirculation of gas that produces in the combustion process and flame.

In this scheme, the stove coal burning rapidly after significant period of time of will working.To provide in order starting and to light flame and furnace wall, heat-transfer area and air preheat actuator temperature are raise, wind and from the mixture of the coal of common main burner, too poor and weak usually and can not promote burning under cold relatively situation.Therefore usual practice be adopt fuel oil or gas igniter/or burning torch so that make the furnace wall, heat-transfer area and air preheater heat up, because these fuel have the advantage that is easy to light, require the heat lighted less.Common electricity consumption spark device of igniter or introduction are on fire, and burning torch is usually on fire with an igniter or a high energy or high-tension electrical equipment.

When coal furnace used another situation of auxiliary fuel to be the load reduction, the input of coal had at this moment been lacked, and it is unstable that flame has become.In this case, use fuel oil or gas igniter/or burning torch be stable in order to keep furnace flame, thereby avoid gathering of unburned coal ash in the stove.

But the above-mentioned advantage of fuel oil or combustion gas intensification and underload rifle now by fuel price soar and the reduction of utilization rate is negated.This situation is also because coal-fired combusting device in service by the aggravation of base load to the variation of circulating load or varying loading, auxiliary petroleum system proposed lotus carved requirement and become more unfavorable to satisfy service requirement.

These problems achieve a solution in the solution of 4,412, No. 496 patent disclosures of the U.S. substantially, and this patent has transferred assignee of the present invention.In this solution, major-minor the sending of being come out by coal pulverizer is provided with a current divider on the pipeline, and it has a movably gas flow modulation baffle plate, and coal and air are divided into two strands.One air communication of being come out by current divider is to a separator, and most of air is separated from the mixed flow of air and coal there.In this scheme, be provided with a low load combustion apparatus, its first nozzle links to each other with separator, most of coal grain stream of discharging and little air in stove, second nozzle also links to each other with this separator, the most of air of separating from separator of discharging in stove.Another strand air-flow that is come out by current divider links to each other with the 3rd nozzle, and discharged air and coal mixed flow make it have high load capacity in stove.

But find not only to have controlled coal but also to have controlled air and can not get a desired effect with a controllable register.All under the operation conditions coal grain is all carried along the upper wall of current divider by this gas flow modulation baffle plate, always there are some coal grains will be in baffle blades slides and fill in gap between baffle plate and the housing, destroy the desired coal grain that flows to each pipeline of downstream and the balance of Air mixing stream.Baffle blades is owing to also can acutely be worn among being in the coal grain for a long time simultaneously.

Therefore, an object of the present invention is to provide for the coal furnace that uses the low load combustion device a kind of current divider of improvement.

Another object of the present invention is in the above-mentioned current divider that is provided, and leads to the coal of stove burner and the control of air capacity and will obtain improving.

Another purpose of the present invention is in the above-mentioned current divider that is provided, and the coal grain will significantly reduce along the slip-stream of baffle blades.

A further object of the present invention is that baffle blades is wear-resistant in the above-mentioned current divider that is provided.

For reaching these purposes, current divider of the present invention can be stipulated the path that the coal that come by external source and Air mixing flow to coal furnace selectively.Current divider has a housing and a retaining device that is placed in the housing of accepting mixed airflow that mixed airflow is divided into two strands.Retaining device can move in housing, to control the mixed flow flow of per share air-flow, separates with the corresponding wall of housing simultaneously, and be the passage that a part of mixed airflow is reserved to form a fixed interval (FI).Retaining device comprises the device of regulating the fixed interval (FI), with the protection baffle blades, prevents that the coal grain is along the blade slip-stream.

To the present invention and the purpose to inventing, the above-mentioned brief description of feature and advantage can also obtain clearer understanding with reference to the detailed description to following most preferred embodiment in conjunction with the accompanying drawings.

Fig. 1 is the schematic diagram of combustion system of the present invention;

Fig. 2 is the plane of current divider that is used for the combustion system of Fig. 1;

Fig. 3 is the 3-3 cutaway view among Fig. 2;

Fig. 4 is the 4-4 cutaway view among Fig. 3;

Fig. 5 is the partial rear view of 5-5 direction among Fig. 1.

Referring to accompanying drawing 1,1 coal pulverizer of sequence number 10 general proxies or coal pulverizer, it has the import 12a and the import 12b who accepts raw coal stream that accept air stream.Two imports that feed coal pulverizer are all being controlled by a load control system of not expressing.Coal pulverizer 10 is worked by common mode, and coal is dry and be ground into quite thin granularity.The end that its top has an outlet to accept the pipeline 14 that coal grind and Air mixing flow links to each other.Pipeline road 14 is provided with a stop valve 16, and it is controlling the coal/air mixed flow that flows to elbow 17 and current divider 18, and elbow 17 links to each other with the other end of pipeline 14, and current divider 18 links to each other with elbow 17.Elbow 17 has rectangle and cuts, and coal is towards the outside 17a of elbow corner under action of centrifugal force.Therefore, when being mixed into current divider 18, the coal grain is just obviously concentrated and is dispersed on the outer surface 17a of elbow corner.Though clearly figure goes up and only at length expressed significant part in the pipeline 14, coal pulverizer can have a plurality of outlets to link to each other with many pipelines of suitable pipeline 14, and these pipelines link to each other with current divider 18 with a plurality of elbows 17 again successively.These outlets, pipeline, the quantity of elbow and current divider is consistent with the quantity of the burner that is used for specific stove.

Current divider 18 is illustrated among Fig. 2-4 in detail, and it has an adpting flange 20 to link to each other with the end of elbow 17.There is a retaining device 22 current divider 18 inside, and current divider is divided into the chamber 24a consistent with elbow 17 ends trends and another chamber 24b of extending out of chamber thus.

Retaining device 22 is a sandwich, and center vane 22a is clipped between ceramic wafer 22b and the carbon steel sheet 22c.Blade 22a one end is contained on the rotating shaft 23, and rotating shaft 23 each end neck are bearing in operating mechanism housing 24a and the 24b, and are being controlled by the operating system of not expressing on the figure, thereby operating system is being controlled the position that retaining device 22 is also being controlled in the rotation of pivot.Plate 22b and 22c are fixed on the blade 22c with commonsense method, and the blade that prevents the back is subjected to the wearing and tearing of coal grain, also will explain below this point.

As shown in Figure 3 and Figure 4, a lamination bar 26a, 26b, 26c and 26d are fixed on common house centipede bolt 28 on the lower edge of retaining device 22, and they are easy to dismantle.More particularly lath 26a is fixed on the lower edge of blade 22a with bolt 28, lath 26b is fixed on the lower edge of 26a with common house centipede bolt 28, lath 26c is fixed on the lower edge of lath 26b with bolt 28, and lath 26d is fixed on the lower edge of lath 26c with bolt 28.Between the lower edge of lath 26d and current divider housing lower wall, formed a crack 30, as shown in Figure 3.Among the lath 26a-26d one or more part can be fixed on and be folded down on the retaining device 22 or from above changing the vertical height in gap 30, will lay down a definition below its reason.

As shown in Figure 4, on the outer surface of plate 22b and lath 26a-26d, many convex shoulders are arranged, to reduce the slip that the coal grain is gone up in the back.When retaining device is in the position that Fig. 2 solid line represents, will enter chamber 24a by most of air-flow of elbow 17; And when in the drawings dotted line position of its place, most of air-flow will enter chamber 24b.The throughput that flows to the air-flow of chamber 24a and 24b depends on the distance of retaining device 22 free ends and current divider 18 sidewalls, and this can control as required with the control system of handling rotating shaft 23.

When retaining device place in the drawings during solid line position, gap 30 also allows a small amount of air-flow to enter chamber 24b, and has a small amount of air-flow to enter chamber 24a during dotted line position in the drawings when the retaining device place.Its quantity depends on the size in gap 30, and the gap is to be determined away by the quantity of the lath 26a-26b on the edge that is added under the retaining device 22.

In the rotation of retaining device 22 with exist under the double action in gap 30, the total air flow of air and coal can be pro rata distributed chamber 24a and 24b under the full load situation, and its ratio has determined desired operating characteristic, and this point also will describe in detail after a while.

As shown in Figure 2, two coupling flange 34a and 34b are bound up on chamber 24a and 24b on conduit 36 and 38 respectively.As shown in Figure 1, conduit 36 extends to burner nozzle device 40 places by current divider, and conduit 38 is come out directly on cyclone separator 42 by current divider.Thereby coal dust and Air mixing that cyclone separator 42 is accepted to be sent here by conduit 38 flow, and work in a general way and separate most of air from mixed flow.The pulverized coal flow of separating contains about 1% little air, is discharged into low lotus conduit 44, and air then enters airduct 46.Conduit 44 and airduct 46 are all received on the burner nozzle 40, and the mode of connection will be described in detail after a while.In airduct 46, be provided with a wind-discharging baffle 48, to control the air mass flow of 46 of conduit 44 and airducts.

The device 40 of burner nozzle is positioned on the same axial line with the through hole 52 on the front wall 54, and the formation of front wall is the same with conventional oven, for example is the part of the such stove of steam boiler.Clearly, the back wall of stove and side wall will have suitable shape to form a combustion chamber 56 in through hole 52 back.Front wall 54 and other wall of stove have suitable refractory material 58, though and do not show especially on the figure, clearly in combustion chamber 56, also arranging boiler tube, heat exchanger fluid, for example water circulates in pipe in normal way, to produce steam.

Vertical wall 60 is parallel with furnace wall 54, has a hole to allow burner nozzle device 40 pass through on it.Clearly, also have the roof of expressing on the figure, diapire and sidewall, they and vertical wall 60 form an inflatable chamber or bellows together, accept the air of burning usefulness in normal way, are commonly referred to " secondary wind ".

Annular slab 62 extends between front wall 54 and wall 60 around burner 40.Be provided with a means of complementary annular plate 64 at annular slab 62 and 54 of furnace walls, it is parallel with annular slab 62 and keep a segment distance.An air baffle sleeve 66 is drawn by means of complementary annular plate 64 inner faces and extension between hole 52 and burner 40, forms two airflow paths 68 and 70.

The outside adjusting vane 72 usefulness pivots of one circle are contained between front wall 54 and the annular slab 62, to control by the rotation of bellows to the secondary wind of airflow path 68 and 70.Use similar mode, a circle internal regulation blade 74 usefulness pivots are contained between annular slab 62 and the means of complementary annular plate 64, with the rotation of further adjusting by the secondary wind of circular passage 70.Although be appreciated that Fig. 1 only drawn two blades 72 and 74, actual have the blade that more blade resembles and express at garden Zhou Fangxiang extend and separate each other.Certainly, the installation of blade 72 and 74 pivots can be finished with common mode, for example blade is contained on the axle (as schematic diagram), axle journal is bearing in the bearing suitable on front wall 54 and plate 62 and 64 again.In addition, blade 72 and 74 position can be with crank or similarly thing adjustment.Because these mechanisms all are common, the explanation in a step has not been done in just not expression yet on the figure.

Burner nozzle 40 comprises 80, one nozzles 82 that communicate with airduct 46 of a nozzle that communicates with conduit 44 and a nozzle 84 that communicates with conduit 36.Nozzle 80(annotates) thus accept to flow by the dense coal grain that separator 42 comes out, and they are arranged in the hole 52 of furnace wall 54.Nozzle 82 is looped around nozzle 80 outsides, and is coaxial with it, thereby forms an annular air channel, accepts the air that come out by separator 42, and it is entered the burning of keeping the dense coal grain stream of being discharged by nozzle 80 in the stove, and the mode back that enters will be described in detail.Outer nozzle 84 is looped around nozzle 82 outsides, and is coaxial with it, thereby forms another circular passage, accepts by the air of current divider 18 and the mixed flow of coal.Nozzle 84 is tapered, thereby and the channel cross-section of 82 formation of nozzle reduce with the air of discharging and the flow path of coal mixed flow by nozzle 84.

Being provided with one group of rotating vane 86 in the circular passage between nozzle 80 and 82 makes the air that enters hole 52 cause eddy flow.Blade 86 can have general shape, and itself can radially have a gradient inwards, and wants in the circular passage between nozzle 80 and 82 that the mode of eddy flow installs so that the air by passage forms.

As Fig. 5 clearly illustrated that, conduit 36 was tangential connections with nozzle 84, so that before air/coal mixed flow heading hole 52, in the annular by nozzle 82 and 84

Annotate: original text is that conduit is wrong.Just formed eddy flow during passage.

Though on figure for the purpose of figure is convenient, do not show, be appreciated that the dense coal grain stream of discharging by nozzle 80 in order in the time of a weak point, to light, also need have various produce light can all kinds of devices.For example, it is other that small-sized oil that the high-energy spark device of an arc light igniter form or a Daepori are logical or gas burning torch can be arranged on burner nozzle device 40.

Suppose that stove discussed above is the part of a steam boiler, and boiler requirement startup, coal pulverizer begins to accept respectively air stream and a small amount of coal stream by its import 12 and 12a, and coal is ground to predetermined granularity.The coal grain mixed flow of little air and porphyrize is discharged from coal pulverizer, enters and by conduit 14 and valve 16, enters current divider 18 by elbow 17.Because preceding discussion is such excessively, the coal grain will be towards the outer surface motion of elbow during by elbow 17 this section passages, entering the coal of current divider 18 bottoms and Air mixing stream major part is air, (as can be seen) as Fig. 1 and Fig. 3, and the major part that enters the mixed flow on current divider top is a coal.Therefore major part coal and portion of air are imported into chamber 24b and conduit 38 when retaining device 22 is on Fig. 2 dotted line position.Because remaining on the balance of the coal in the current divider 18 is at an upper portion thereof, and air is in its underpart, therefore quantitatively many relatively air and relative few coal will be under the hydrostatic pressure that separator 42 and its downstream components generation resistance cause below retaining device 22 gap 30 enter chamber 24a.Enter the air of chamber 24a and coal by this way with inflow catheter 36 and nozzle 84.

Coal by chamber 24b and Air mixing stream mainly is the coal that just ground when starting as previously mentioned.Mixed flow flows through conduit 38, enters separator 42, is separated into dense coal grain stream and air stream, enters nozzle 80 and 82 by conduit 44 and 46 respectively.The dense coal grain stream that comes out by nozzle 80 with before nozzle 80 and 82, fully mix under spin that 86 pairs of air of blade cause and the cyclonic effect that forms vortex by a wind of nozzle 82 discharges and recycle.The way that the well-mixed coal gas stream of result can be said by the front is rapidly for example directly lighted with high-energy spark or oil ignitor or gas igniter.Though the discharge capacity of the coal of coal pulverizer is little, the abundant mixture that the fuel stream of concentrating forms has require and essential burning-point.The recirculation that the vortex that this scheme forms has produced the comburant that has blazed up is lighted required heat for the fresh fuel that enters the combustion zone provides, and this is that we are desirable.

The increase of unit load can be finished by the similar way that drops into multi-combustor more or drop into many coal pulverizers on the basis of same coal pulverizer.When the coal pulverizer that requires and burner all drop into, also require to increase load, finish with regard to the way of every coal pulverizer coal stream of available increase.At this moment, the retaining device 22 that links with every coal pulverizer 10 rotates to chamber 24b, makes the part of coal grain stream that concentrates on current divider 18 tops enter chamber 24a in company with an a large amount of wind, enters nozzle 84 through conduit 36.

Along with the flow of coal increases to maximum, retaining device 22 constantly rotates to chamber 24b, until near till the solid line position shown in Figure 2.At this moment, the coal/air mixed flow that enters chamber 24a reaches maximum, and mixed with little amount stream passes through retaining device 22 by gap 30 simultaneously, chamber 24b, and conduit 38 enters separator 42.By retaining device 22 and coal pulverizer output load characteristic coal and the air capacity that enters separator 42 and underload nozzle 80 and 82 can be controlled at (be about the 5-20% when completely cutting) on the low heat input value simultaneously the load of main burner 84 also can increase as required or reduce.Can keep sufficient eddy flow by low load combustion device 80 and 82, although along with load increases, master selector and secondary wind will further strengthen the stable influence of whole burner.

Be appreciated that whether such scheme will have preheated air to depend on the moisture that fuel is contained.If necessary, can provide desired heat, enter the temperature of a wind of coal pulverizer 10 with raising by normal air heating duct device.

The present invention is not limited in above-mentioned disclosed particular burner and the burner scheme, as long as above-mentioned conclusion can reach it and also can be suitable for other allocation plan.This point also is understandable.In addition, except that cyclone separator above-mentioned, the separator of various types all can be used in the design of the present invention.

Can draw from the above mentioned some advantages of the present invention. For example, the dense coal grain that the energy that igniting consumes only takes place directly to light by nozzle 80 flows the required utmost point in the short time, starts afterwards and heat up all to finish by dense coal grain stream with by the burning itself that the whirlwind of nozzle 82 is facilitated. Simultaneously, dense coal stream underload nozzle 80 can make main coal filariasis flame stable in wide load range, makes flexible operation and seldom needs auxiliary fuel. In addition, the method for available adjusting play 30 makes conduit 36 and 38 obtain suitable air stream, and a wind that enters conduit 38 that will exceed simultaneously the burning needs is discharged into conduit 36, because a wind of excess still needs coal pulverizer and conduit thereof. In addition, during high load capacity, adjustable gap 30 can make the quantity of the air that flows to the underload system and coal controlled, to keep the flame of burner. Moreover the plate 22b on the retaining device 22 and the convex shoulder on the lath 26a-26d can prevent from gliding on the coal grain is by plate when it is in dotted line position shown in Figure 2 and falling into gap 30. Another advantage is that ceramic wafer 22b and carbon steel sheet 22c launch at two faces of baffle blades 22c, protect it to avoid wearing and tearing.

Be appreciated that described system and method also applicable to most of existing systems and any new equipment, because air-flow can tell at various parallel pipelines, and the additional pressure loss can be controlled in very little.

Still leave improvement in the above in the invention disclosed, conversion and the Yu ground that substitutes can adopt some feature of the present invention in some situation, and feature that need not be other. Therefore, wider range of the claim of enclosing, and be consistent with spirit of the present invention and the field that relates to, work is suitable like this.

Errata

Claims (13)

1, a kind of coal and Air mixing stream is delivered to the current divider of coal furnace by an external source, this current divider is made up of a housing and a retaining device that this mixed flow is divided into two strands of air-flows that is arranged in this housing of accepting this mixed flow.This retaining device can move in housing to control the flow of mixed flow in the per share air-flow.This retaining device separates with the corresponding wall of housing, with form a fixed interval (FI) allow partially mixed stream by and with the location independent of retaining device.This retaining device comprises the device that changes this fixed interval (FI).

2, according to the current divider of claim 1, the device that wherein changes the fixed interval (FI) size is made up of a plurality of laths and the connecting piece that lath is connected on the retaining device that can dismantle rapidly.

3, according to the current divider of claim 1 or 2, wherein retaining device is made up of baffle blades and a pair of plate topped and that be fixed on the baffle blades two sides.

4, according to the current divider of claim 3, wherein a plate is a steel for another piece plate of pottery.

5, according to the current divider of claim 1, stretched out many convex shoulders, moved along this device to stop coal from retaining device.

6, according to the current divider of claim 4, stretched out many convex shoulders, moved along this plate to stop coal from ceramic wafer.

7, a kind of coal and Air mixing stream is delivered to the current divider of coal furnace by an external source, this current divider is made up of a housing and a retaining device that this mixed flow is divided into two strands of air-flows that is arranged in this housing of accepting this mixed flow.This retaining device can move in housing to control the flow of mixed flow in the per share air-flow.This retaining device is made up of a baffle blades and a pair of plate topped and that be fixed on this baffle blades two sides.

8, according to the current divider of claim 7, wherein a plate is a pottery, and another piece is a steel.

9, according to the current divider of claim 7, stretched out many convex shoulders, moved along this device to stop coal from this ceramic wafer.

10, a kind of current divider of coal coal and Air mixing stream being delivered to coal furnace by an external source, this current divider is made up of a housing and a baffle plate that this mixed flow is divided into two strands of air-flows that is arranged in this housing of accepting this mixed flow, and this baffle plate can move in housing to control the flow of mixed flow in the per share air-flow.Stretch out many convex shoulders from this baffle plate, move both vertically along this device to stop coal.

11, according to the current divider of claim 10, wherein baffle plate is made up of a blade and a pair of plate topped and that be fixed on the blade two sides.

12, according to the current divider of claim 11, wherein one is pottery, and another piece is a steel.

13, according to the current divider of claim 12, many convex shoulders have been stretched out from ceramic wafer.

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