DE19706077A1 - Hot gas generator with burner for dust fuels - Google Patents

Abstract

Dust fuels (12) and combustion air (13) are supplied to a burner (10) generating hot gases, e.g. for drying. A muffle (6) at the outlet of the burner is made of metal plates (2) forming a structure with nozzle slots (3,4) through which cooling gas (11) is supplied. The plates are preferably curved and have chamfered butting edges to form vertical (3) and horizontal (4) nozzle slots, respectively parallel and transverse to the longitudinal axis of the muffle. Plates are preferably of cast iron or cast steel and have a rectangular shape in plan view. The angle of the nozzles is between 25 and 55 degrees, depending on the diameter of the muffle.

Description

The invention relates to a hot gas generator with a Burner according to the preamble of claim 1 and a Wall element for a burner muffle, especially a hot one gas generator.

Hot gas generators enable different combustion heating media. Gases, light oil, Heavy oil, coke, coal and other combustible dusts be set. The hot gases generated thereby become dry purposes, for example in mills, drum dryers, Floating dryers or electrostatic filters, or for heating from exhaust gases from technical processes to a desired one Temperature level used.

In hot gas generators with a dust burner in particular their solid, ash-containing fuels, such as hard coal, Lignite, peat, wood, biomass and the like, ver burns. The pneumatically conveyed fuel dust is also how the combustion air is fed to the burner. In a The burner flame creates the burner mouth. The flames out education takes place in a subsequent burner muffle and the flame burnout in downstream, made of perforated sheet metal alleviate existing sections of a perforated jacket. From the hot gas generator escaping hot gases are dependent of their use by cooling air or cooling gas, for example by a recirculation gas, on the desired temperatures in the range of approx. 90 to approx. 750 ° C quenched.  

This is usually done by the hot gas generator supplied cooling air or the cooling gas through an annular duct at the end of the burner muffle in the hot flue gas stream Dust flame is injected. The injection of the cooling gases or the cooling air takes place via ring or individual nozzles and / or through holes in the perforated cylinder sections.

Known hot gas generators (DE 42 08 951 A1) have one Burner muffle, which with refractory material, for. B. with firebricks, bricked or with ceramic Ramming masses is lined. This well-known hot gas Witnesses, especially when using a dust burner ners, disadvantages.

The fireproof or ceramic lining requires egg ne relatively long heating-up time, which leads to considerable start-up times leads and costs. The control speeds are too too small in a large number of systems. The departure or Can switch off due to the high storage heat capacity of the lining material lead to problems. In cases an emergency shutdown must prevent the storage heat damage caused by overheating. From the For this reason, such hot gas generators require the Installa tion of an emergency fireplace. In addition, cooling with With the help of a trailing fan. The Cold start numbers are limited, and in the case of a non-beach The operating restrictions can destroy the Lining material, malfunctions and breastfeeding downstream systems come.

Another disadvantage is that the partial liquid ash-slag particles from the flames of the Dust firing for caking on the ceramic burner  walls with the consequence of slag bear formation and thus to destroy the combustion chamber lining and to a Flame formation can lead to disruption.

There are also increased requirements for hot gas generators and particularly to dust-fired hot gas generators poses.

The invention has for its object a Hot gas generator, especially with a dust burner too create, which the requirements in relation to a high Control speed, short start-up and shutdown times and corresponds to relatively large cold start numbers and at which Caking and destruction of the burner chamber wall almost be avoided.

According to the invention the task is characterized by the features of the spell 1 solved. Practical and advantageous design are contained in the subclaims.

An essential idea of the invention is a Torch muffle to use without brick lining and metallic To provide wall elements for the burner muffle, which by the cooling gas or the cooling air to be heated is flushed or be washed around so that no slag deposits occur. There no ceramic materials are used, are high Control speed and cheap quick start and Ab switching conditions guaranteed.

According to the invention in a generic hot gas producers by a burner, especially a dust burner, flame formed in a brick-free and out Metal plates formed directed muffle. The Me  tallplatten, which is basically any geometric shape or can have a contour for a wall forming bandage is suitable, with marginal Provide areas or abutting edges, which in neighboring or adjacent metal plates of an association such wall elements for the formation of horizontal and / or vertical slot nozzles. As horizontal Slot nozzles are approximately parallel and vertical Slit nozzles approximately transverse or at right angles to the longitudinal axis of the Burner muffle or the hot gas generator running Called slot nozzles.

The slot nozzles are expediently aligned in this way tet that the cooling gas supplied or the cooling air with a defined inflow angle flows into the burner muffle and the metal plates are rinsed or washed around in this way, that sticky ash particles don't reach the metal plates arrive, but are removed due to the current.

Preferred designs of the burner muffle see quadrati cal and in particular rectangular metal plates, which curved out according to the radius of the burner muffle forms are. Each metal plate has a ge curved front and a parallel curved back provided. Beveled or angled butt edges, d. H. a bevelled lower edge and / or upper edge and / or beveled side edges, which in plan view Represent parallelogram, form almost together metal plates attached to the vertical and / or horizontal slot nozzles.

Slag has been found to be particularly effective sets can be avoided if the nozzle angle of the Slit nozzles for muffle sleeves with a small diameter  knife relatively small and with a re relatively large diameters are larger. So had a nozzle for combustion chambers in the power range up to 3 MW angle between 25 ° and 30 ° and in power range up to 30 MW a nozzle angle between 50 ° and 55 ° as the optimal nozzle angle to avoid ash and Slag caking on the metal plates of the inventor proven burner muffle.

Advantageously, the nozzle angle should be horizontal ordered slot nozzles the same size or smaller than that Angle of the vertical slot nozzles can be formed. A particularly efficient cooling is achieved when the Lower and upper edge as well as the side edges of the metal plate th are each formed parallel to each other and if the vertical slot nozzles tangential and the horizontal Slot nozzles obliquely downwards, d. H. downstream, out forms are.

The size of the preferably identically formed metal plates has an influence on the tendency to contamination or slagging of the muffle wall, proportional to the combustion chamber performance. The following dimensions have proven to be optimal values for minimizing the tendency to slagging:

• - up to the 3 MW power range H = 250 mm, W = 200 mm
• - up to the 30 MW power range H = 600 mm, W = 750 mm
• - For outputs between 3 and 30 MW, it is advisable for Use H (height) and B (width) proportional values.

In addition to the size of the metal plates and the nozzle angles of the slot nozzles, the width of the nozzle slots has a significant effect on the tendency to slagging. The performance-dependent values for the slot width S for a slag-free operation are:

• - up to the power range 3 MW S = 6-8 mm
• - up to 30 MW S = 20-32 mm
• - For outputs between 3 and 30 MW, it is advisable for S use proportional values.

The effect of the vertical and horizontal slot nozzles can be achieved by additional nozzle openings, which are inside the Metal plates are formed to be increased. Expedient these integrated nozzle openings are corresponding aligned with the bevelled edges to one to ensure the inflow angle adapted to the slot nozzles most. The integrated nozzle openings can be horizontal or vertical, parallel to each other or offset be educated. The nozzle openings can also be used as a bore gene with the same or different diameter, for. B. in the sense of a perforation. For example the metal plates can be perforated accordingly be made of sheet metal.

Another improvement regarding the cooling gas flow The quantity and speed is determined by deflection or peeling edges reached. These represent an outward facing Extension of the beveled or angled top edge a metal plate, whereby the cooling gas in the horizon valley slot nozzles is deflected. Wall plates with deflection or Peeling edges are particularly useful for fuels low ash melting point.

When using fuels with low volatile Be constituents, it is appropriate to use the cooling gas or the cooling air to a temperature of around 400 ° C before  this enters the burner muffle through the slot nozzles. The heating, which supports CO post-oxidation, is in a further development of the invention by Ausformun conditions on the back of the metal plates, for example by ribs.

The rear or ceiling side is expedient The burner muffle is also finished with metal elements Mistake. However, these do not point to those of angled Butt edges formed vertical and horizontal slot nozzles, but holes through which the cooling gas in the Flowing around the edge of the burner muffle and slagging can prevent.

A rear or ceiling egg is particularly advantageous area of the burner muffle, in which the holes on the Muffle edge can be dimensioned larger than in the center. On this way the muffle wall is flushed with cooling air or cooling gas improved.

Surprisingly, it was found that the fall distillers, d. H. known in ceiling burners, increasingly on partial inertization of the flame root with one there due to the risk of flame emigration occurs. This is due to the fact that greater marginal ventilation a recirculation of the burned out Smoke gases in the edge area reduced or suppressed becomes.

A reduced hot gas recirculation in the burner root zone generally leads to a reduction in the tendency to slagging on the muffle wall. In a further development of the invention, a correspondingly long Brennkam mer is provided for an efficient burnout of a dust flame. This provides the flame with a sufficiently long and hot combustion path before cooling air or a cooling gas is injected into the flue gases heated to suppress the combustion. In order to limit the investment costs and the space requirement to a suitable size at the same time, it is planned to connect at least two and a maximum of four perforated plate cylinder sections with through holes to the burner muffle, in which the sum of the free hole cross sections should be staggered as follows depending on the output:

Through such a performance-based grading, a good burnout in the burnout-specific temperature range ensured.

The burnout-promoting effect of the aforementioned perforated sheet Cylinder sections will also be effective under supports when in the ring nozzles between the perforated plate cylinder the sections of swirl plates are provided.

To promote the desired burnout is out the provided, at least in the perforated plate cylinder cut, which connect to the burner muffle, bead holes to form as holes. Through these bead holes the cooling gas or the cooling air can only delay the hot Combustion gases are supplied.

The invention is based on a drawing ter explained; in this show in a highly schematic presentation:

Fig. 1 is an axial longitudinal section through a gas generator OF INVENTION to the invention hot;

FIG. 2 shows a view according to arrow II according to FIG. 1;

Fig. 3 is a plan view of Wandplat th inventive burner muffle;

FIG. 4 shows a longitudinal section along line IV-IV according to FIG. 3;

Fig. 5 is a cross sectional view along line VV of FIG. 3;

Fig. 6 is an enlarged section in the region of the perforated shell of the hot gas generator according to the invention according to FIG. 1 and

Fig. 7 is a cross section along line VII-VII of Fig. 6.

Fig. 1 shows in a highly schematic representation of the structure of a hot gas generator 1 of the invention. FIG. 2 shows a top view of the hot gas generator 1 according to arrow II according to FIG. 1.

The hot gas generator 1 , which is arranged vertically in this exemplary embodiment and is placed on a scaffolding structure 32 via claws 31 , has a burner 10 . The burner 10 is a dust burner, the dust-like ground fuels 12 via a dust entry 34 and combustion air 13 are supplied via an air inlet nozzle 33 . A flame arises in a burner mouth 9 , the flame formation takes place in a flanged burner muffle 6 and the flame flames in a downstream perforated jacket 14 .

The perforated jacket 14 consists of a plurality of perforated sheet metal cylinder sections 16 which are arranged within a housing or protective jacket 15 with diameters increasing in the axial direction and at overlap areas for supplying a partial flow 35 of the cooling gas 11 , for example of process air, with annular openings 27 are provided (see Fig. 6). The cooling gas 11 , for example cooling air or a recirculation gas which is to be heated in the hot gas generator 1 , is supplied via a spiral housing 36 , which is arranged coaxially to a region of the burner muffle 6 on the burner side, and passes via an annular channel 17 to the perforated jacket 14 .

The exiting at 38 from the hot gas generator 1 hot gases are cooled by the cooling gas 11 to the desired temperature s by the cooling gas 11 is injected via the annular openings 29 and through holes 20 of the perforate shell 14 in the flue gas stream of the combustion chamber 30 (Fig. 6) .

Fig. 1 illustrates that the combustion chamber 30 formed in the area of the burner muffle 6 and the perforated jacket 14 is relatively long. The burner muffle 6 has almost the same length as the perforated jacket 14 consisting of four perforated sheet cylinder sections 16 . In this way, the flame has a sufficiently long, hot combustion path before the cooling gas 11 is injected and the combustion is suppressed.

Due to the relatively long combustion chamber 30 , a particularly good burn-out of dust-like fuels is achieved.

Fig. 1 also shows the inventive design of the burner muffle 6 , which consists of masonry, arranged into a bandage, plate-shaped wall elements 2 be. The plate-shaped wall elements 2 are formed in an extremely efficient manner as metal plates 2 and arranged in such a way that horizontal and / or vertical slot nozzles 3 , 4 are formed. Through these slot nozzles 3 , 4 , the cooling gas supplied via the spiral housing 36 flows in and flushes or rinses the metal plates 2 in such a way that no slag deposits can form. At the same time, high control speeds and very good quick start and shutdown conditions are achieved due to the high load change speed of the metal plates.

An enlarged representation of the metal plates 2 used for the burner muffle 6 is shown in FIGS. 3 to 5. Fig. 3 illustrates the formation and arrangement of the metal plates 2 to form a bandage in which the metal plates 2 are offset and arranged "on a gap". To form the horizontal and vertical slot nozzles 3 , 4 metal plates 2 with bevelled or angled th abutting edges 5 are arranged side by side and one above the other. The metal plates 2 are, as can be seen in particular from FIG. 5, curved according to the diameter of the burner muffle 6 , wherein a front 21 and a parallel rear 22 have this curvature, while a lower edge 23 , an upper edge 24 and side edges 25 each Metal plate 2 have the shape of a parallel log in plan view. Rinsing or flushing the Metallplat th 2 is particularly effective achieved by nozzle angle α or β, which should be chosen depending on the diameter of the burner sleeve 6 to avoid slag deposits. Basically, the nozzle angle α, which is formed by the bevelled lower edge or upper edge 23 , 24 and a horizontal, should be equal to or smaller than the nozzle angle β, which defines the beveling or angling of the side edges 25 and thus the orientation of the vertical slot nozzles 4 .

The metal plates 2 are approximately rectangular if a top view of the front 21 or rear 22 is assumed. The size of the metal plates 2 is determined by the height H, width B and depth T. Metal plates 2 can advantageously be used depending on the combustion chamber performance with a height of 250 to 600 mm, a width of 200 to 750 mm and a depth T or the slot width S of 6 to 32 mm.

To improve the washing around the wall panels 2 , these can be provided with a deflecting or peeling edge 18 (FIGS . 3 and 4). The deflection edge 18 is directed towards the outside in the extension of the upper edge 24 and thereby directs the cooling gas 11 in the direction of the slot nozzle 3 . By also increasing the amount and speed of the cooling gas 11 flowing through the slot nozzle 3 , slag deposits, particularly in the case of fuels with low ash melting points, are effectively avoided.

Another special form of a metal plate 2 is shown in Fig. 3 and Fig. 5. In order to respectively heat the cooling air to a temperature to about 400 ° C in the use of fuels with low volatiles, the cooling gas 11 before it enters through the horizontal and verti cal slit nozzles 3, 4 in the combustion chamber 30 in the region of the burner muffle 6 , Two exemplary Ausformun gene 19 are formed in the form of ribs on the back 22 of the lower right metal plate 2 .

An additional flushing of the metal plates 2 is achieved through nozzle openings 7 which are integrated in the metal plate 2 . In Fig. 3 and 4, the integrated nozzle openings 7 are arranged offset and approximately cuboid. In principle, the integrated nozzle openings 7 could also run in the vertical direction.

Instead of or in addition to the nozzle openings 7 , perforations 37 can be made as a plurality of bores 37 , for example 30 to 40 bores 37 per metal plate 2 . The diameter of a hole can be about 4 to 5 mm. These holes also rapidly cool ash particles that settle on the metal plates 2 . This rapid cooling causes an amorphous formation of the on or through melted particles and prevents intensive adhesion to the metal surface. If the layer becomes too heavy due to further growth, the weight will fall off.

A rear or ceiling end of the combustion chamber 30 and the burner muffle 6 is realized by perforated Me tallplatten 8 ( Fig. 1). The holes on the radially outer region of the burner muffle 6 are expediently dimensioned to increase the flow around the metal plates 2 of the wall. Due to the better edge ventilation of the ceiling of the combustion chamber 30 , recirculation of the burned-out flue gases in the edge region is reduced and thus also a partial inertization of the flame root is suppressed.

Fig. 6 and Fig. 7 show an embodiment of the perforated jacket 14 in the region of the annular openings 29 between the perforated jacket cylinder sections 16th In the ring-shaped openings 29 to ensure a good burnout of a dust flame, swirl plates 17 are arranged, with which a delayed introduction of the cooling gas 11 or the cooling air into the hot combustion gases can be regulated. A delayed introduction of cooling air or cooling gas 11 into the hot combustion gases of the combustion chamber 30 is also served by the holes 20 of the perforated jacket cylinder sections 16 which are designed as corrugated holes 38 . These bead holes 38 are advantageous in the cylinder sections 16 , which connect to the burner muffle 6 , to provide.

Claims (24)

1. Hot gas generator
with a burner ( 10 ), to which in particular dust-shaped fuels ( 12 ) and combustion air ( 13 ) can be supplied, with a burner muffle ( 6 ) arranged on the outlet side on the burner ( 10 ), a feed for cooling gas ( 11 ) to be heated and with one of the burner muffle ( 6 ) downstream perforated jacket ( 14 ), which consists of staggered cylinder sections ( 16 ) and forms an annular channel ( 17 ) for the cooling gas ( 11 ) with a protective jacket ( 15 ), characterized in that
that for the burner muffle ( 6 ) metal plates ( 2 ) are seen before, which nozzles ( 3 , 4 ) are arranged in a formation with the formation of slot and can be flushed by the cooling gas ( 11 ) that can be supplied through the slot nozzles ( 3 , 4 ). 2. Hot gas generator according to claim 1, characterized in that the to a cylindrical wall ( 28 ) of the Bren nermuffel ( 6 ) arranged metal plates ( 2 ) are curved and have chamfered abutting edges ( 5 ), which have vertical slot nozzles ( 3 ) and hori form zonal slot nozzles ( 4 ), the vertical slot nozzles ( 3 ) approximately parallel and the horizontal slot nozzles ( 4 ) approximately transverse to the longitudinal axis of the burner sleeve ( 6 ). 3. Hot gas generator according to claim 1 or 2, characterized in that the metal plates ( 2 ) each have a curved front side ( 21 ) and a parallel rear side ( 22 ) and a beveled bottom edge ( 23 ), top edge ( 24 ) and beveled side edges ( 25 , 26 ) as abutting edges ( 5 ) and that formed by the abutting edges ( 5 ) of adjacent metal plates ( 2 ) formed horizontal and vertical slot nozzles ( 3 , 4 ) the cooling gas ( 11 ) at an inflow angle into the burner muffle ( 6 ) is. 4. Hot gas generator according to one of claims 1 to 3, characterized in that the metal plates ( 2 ) are made of cast iron or cast steel and have a rectangular contour in a plan view of the front or back ( 21 , 22 ). 5. Hot gas generator according to claim 3 or 4, characterized in that the side edges ( 25 , 26 ) and the upper and lower edges ( 23 , 24 ) of the metal plates ( 2 ) are so beveled or angled so that the horizontal and vertical slot nozzles ( 3 , 4 ) are arranged in a nozzle angle α or β in the range from at least 25 to a maximum of 55 °. 6. Hot gas generator according to claim 5, characterized in that the nozzle angles α and β of the horizontal and vertical slot nozzles ( 3 , 4 ) are designed according to the diameter of the burner muffle ( 6 ). 7. Hot gas generator according to claim 5 or 6, characterized in that the nozzle angle α of the horizontal slot nozzles ( 3 ) is the same size or smaller than the nozzle angle β of the vertical slot nozzles ( 4 ). 8. Hot gas generator according to one of claims 3 to 7, characterized in that the lower and upper edge ( 23 , 24 ) and the side edges ( 25 , 26 ) are each formed parallel to one another and as a parallelogram, that the vertical slot nozzles ( 4th ) tangentially and the horizontal slot nozzles ( 3 ) are angled downwards and aligned with the burner muffle ( 6 ). 9. Hot gas generator according to one of the preceding claims, characterized in that the metal plates ( 2 ) have a width B of at least 200 mm and a maximum of 750 mm, a height H of at least 250 mm and a maximum of 600 mm and a depth T and a Have nozzle slot width S of at least 6 mm and a maximum of 32 mm. 10. Hot gas generator according to one of the preceding claims, characterized in that at least one further nozzle opening ( 7 ) is provided for supplying the cooling gas ( 11 ) and that the further nozzle opening ( 7 ) is integrated into the metal plates ( 2 ). 11. Hot gas generator according to claim 10, characterized in that the integrated in the metal plates ( 2 ) nozzle openings ( 7 ) are formed horizontally and / or vertically and of the type that the cooling gas ( 11 ) with one of the slot nozzles ( 3 , 4th ) correspond to the inflow angle. 12. A hot gas generator according to claim 11, characterized in that a plurality of nozzle openings ( 7 ) integrated in the metal plates ( 2 ) are formed parallel to one another or offset. 13. Hot gas generator according to one of the preceding claims, characterized in that the rear sides ( 22 ) of the metal plates ( 2 ) with egg ner deflecting or peeling edge ( 18 ) are provided, that the deflecting edge ( 18 ) the beveled or inclined upper edge ( 24th ) extended outwards and the cooling gas ( 11 ) deflected into the horizontal slot nozzles ( 3 ). 14. Hot gas generator according to one of the preceding claims, characterized in that the metal plates ( 2 ) with formations ( 19 ) are seen ver, which are designed for preheating the cooling gas ( 11 ) on the rear sides ( 22 ). 15. Hot gas generator according to claim 14, characterized in that the formations ( 19 ) are designed as ribs and through the slot nozzles ( 3 , 4 ) of the burner sleeve fe ( 6 ) coolant gas can be supplied to a temperature of at least 140 ° C and a maximum of 400 ° C is preheat bar. 16. Hot gas generator according to one of the preceding claims, characterized in that the burner muffle ( 6 ) is provided with perforated metal plates ( 8 ) to the rear or to the ceiling. 17. Hot gas generator according to claim 15, characterized in that the perforated metal plates ( 8 ) have holes in the edge region with a larger free cross section than in the center. 18. Hot gas generator according to one of the preceding claims, characterized in that the burner muffle ( 6 ) are arranged at least two Lochman tel-cylinder sections ( 16 ) and that their free hole cross-sections are staggered depending on performance. 19. Hot gas generator according to claim 18, characterized in that the free hole cross sections of at least two and a maximum of four perforated jacket cylinder sections ( 16 ) are staggered as follows: with two perforated jacket cylinder sections ( 16 ): 35-65%, with three Perforated cylinder sections ( 16 ): 20-30-50% and for four perforated cylinder sections ( 16 ): 20-20-30-30%. 20. Hot gas generator according to one of the preceding claims, characterized in that swirl plates ( 27 ) are arranged between the perforated cylinder sections ( 16 ), which flow through the annular channel ( 17 ) cooling gas ( 11 ) flow in part and tangentially in each Introduce the following perforated cylinder section ( 16 ). 21. Hot gas generator according to one of the preceding claims, characterized in that in the perforated jacket cylinder sections ( 16 ) provided holes ( 20 ) are formed as bead holes. 22. Hot gas generator according to one of the preceding claims, characterized in that the metal plates ( 2 ) are provided with a perforation ( 37 ). 23. Hot gas generator according to claim 22, characterized in that a plurality of bores ( 37 ) are provided as the perforation ( 37 ), which in particular have an approximately circular cross section and a diameter of 4 to 5 mm. 24. Wall element for a burner muffle, in particular for a hot gas generator according to the preamble of claim 1, characterized in that it is made of a metallic material and has beveled abutting edges ( 5 ) which, when arranged in a bandage, horizontal and / or vertical Form slot nozzles ( 3 , 4 ), and that it can be flushed from egg nem through the slot nozzles ( 3 , 4 ) coolant gas ( 11 ).