EP4209708A1 - Radial nozzle solid fuel gasification heater - Google Patents

Abstract

The invention relates to a heater for solid fuel gasifiers with a radial nozzle, a gasification chamber (4) with a floor (10), a combustion chamber (9) arranged below the gasification chamber, the floor (10) of the gasification chamber (4) being inclined towards its center and through four sloping walls (11) are defined, forming a pyramid shape with the top pointing towards the combustion chamber (9) or a trough shape, while the gasification chamber (4) and the combustion chamber (9) are separated by a partition wall (5) placed on the side of the gasification chamber (4) forms the bottom (10) of this gasification chamber and on the side of the combustion chamber (9) the upper inner wall (7), while the partition wall (5) is guided by the nozzle (2), the inlet opening (1) of which is in the Bottom of the gasification chamber (4) and the outlet opening (3) in the inner wall (7) of the combustion chamber (9) is formed.

Description

This invention relates to a solid fuel radial nozzle type gasification heater.

The concept of solid fuel gasification or pyrolysis heaters is widely used. It is mainly used in hot water wood-fired boilers with manual charging and to a lesser extent in wood-burning stoves.

Known heaters of this concept contain a gasification chamber in the upper part and a combustion chamber in the lower part. The gassing chamber is almost always square or rectangular in cross-section. In the upper part it contains a hole for filling fuel. The gasification chamber and the combustion chamber are separated by a partition. The partition wall thus forms the floor of the gasification chamber with its upper surface and the ceiling of the combustion chamber with its lower surface. The partition contains a nozzle (vent or through hole) that connects the gasification chamber and the combustion chamber. The entrance opening (Slit) of the nozzle is usually located in the center of the bottom of the gasification chamber. The outlet of the nozzle is in the wall that usually forms the ceiling of the combustion chamber.

The bottom of the gasification chamber can be horizontal or inclined towards the nozzle. The sloping floor of the gasification chamber is thus in the shape of a four-sided pyramid with the apex down, with 4 triangular walls, or a four-sided trough with a pair of opposing triangular walls and a pair of trapezoidal walls.

• Gasaustritt aus der Vergasungskammer, während es normalerweise wünschenswert ist, dass sich der Auslass im mittleren Teil des Bodens der Vergasungskammer befindet, wo der Energiewert (Temperatur und Heizwert) des Gases am höchsten ist.
• Entaschung vom Boden der Vergasungskammer.
• Eindämmung von unverbrannten Teilen des Brennstoffs (Kohle) in der Vergasungskammer (damit sie nicht in die Brennkammer fallen).

The gasification heater works as follows: The fuel becomes gas in the gasification chamber. It flows through the inlet opening into the nozzle, where it burns. The fuel gas flows through the nozzle outlet into the combustion chamber. In the nozzle, air is usually directed into the flame, which promotes combustion. The air is usually directed through an opening in the bulkhead, which opens into the nozzle. Thus, the nozzle of the gasification heater performs several functions:

• Gas outlet from the gasification chamber, while it is usually desirable that the outlet be located in the middle part of the bottom of the gasification chamber, where the energy value (temperature and calorific value) of the gas is highest.
• Ash removal from the bottom of the gasification chamber.
• Containment of unburned parts of the fuel (coal) in the gasification chamber (so that they do not fall into the combustion chamber).

The nozzle is therefore an important element, and its quality has a significant impact on the quality of the heater as a whole. From the stated functions of the nozzle it is clear that the requirements for the spatial arrangement of the nozzle are quite contradictory: the removal of gases and ash requires large nozzle dimensions, while the collection of unburned particles or mixing with air requires small nozzle dimensions . The ash removal requires multiple inlets in the tray area, while gas removal requires an inlet in the center of the tray. During operation, the walls of the nozzle are exposed to high temperatures (up to 1100°C), gas effects (oxidation and reduction reactions, etc.), ash effects (melting, high-temperature alkaline corrosion, etc.) and mechanical stress from parts of the fuel. This places extraordinary demands on the selection of the materials used.

The walls of the nozzle can be made of heat-resistant metal alloys of iron (refractory steel and cast iron). This material is strong and allows you to create any shape (for example, a grate), but its temperature resistance is insufficient and its service life is short.

Therefore, ceramic is most often used for the walls of the nozzle. Ceramics withstand temperatures well, but are fragile. The strength, especially under tension, is many times lower than that of metallic materials. Therefore, the ceramic parts must be solid, which imposes significant dimensional limitations.

The facts mentioned make it clear that the requirements for the dimensional arrangement of the nozzle are significant.

Known nozzle types differ mainly in the shape and number of inlet holes. Most often, nozzles with an inlet opening and a rectangular cross section with a significant side difference (elongated) are used. There are also square or round nozzles. For nozzles with a single inlet port, the nozzle vent usually follows the inlet port. The cross-section of the vent widens downwards to prevent parts of the fuel from sticking. The outlet port is therefore usually identical to the inlet port, but slightly larger. For nozzles with a larger number of inlet holes the vents from each inlet hole are usually connected to a single outlet hole.

As mentioned earlier, the requirements for the nozzles are conflicting, so each type of nozzle has a different combination of advantages and disadvantages. For example, a square or round nozzle, due to its central position in the bottom, achieves a higher energy value of the gas (and thus combustion quality), but has the disadvantage of a large waste of fuel parts, which are then missing in the gasification chamber. This reduces the efficiency of gasification, while the fuel parts in the combustion chamber are troublesome and deteriorate the quality of gas combustion. On the other hand, a rectangular nozzle has the advantage (because it is significantly narrower for the same area) that parts of the fuel lose a small drop. However, their disadvantage is that their ends reach into the edge areas of the ground, where the energy value of the gas is lower. This reduces the overall quality of the combustion. The inhomogeneity of the gas flow then impairs proper mixing with the secondary air. This requires, for example, the need for a homogenization (mixing) chamber behind the outlet of the nozzle, which makes the heater more expensive but also more complicated.

Efforts to achieve the greatest possible proportion of the above advantages lead to the design of nozzles with a relatively small area of the inlet opening, which increases the gas throughput and thus the pressure loss of the nozzle. To do this, for example, the heater must be equipped with a fan, while the fan power also increases with increasing pressure loss of the nozzle. High gas velocities locally increase the intensity of oxidation reactions, which increase the temperature due to the increased formation of harmful NOX emissions (nitrogen oxides) or cause undesirable melting of ash (slag formation).

Nozzles with a larger number of inlet holes have favorable operating characteristics. However, for reasons of strength, they do not allow the use of ceramic material, so they must be made of metal. They therefore also have a short service life and have to be changed frequently, which makes operation more expensive.

Some types of gasification heaters are characterized by a sharply sloping floor of the gasification chamber towards its center - or the nozzle. The bottom thus forms the shape of a four-sided pyramid with the apex at the bottom. With a sufficient angle of fall (more than 40°), the ash slides down the bottom walls into the nozzle during operation, which is a significant advantage. However, this type of soil also has disadvantages. It limits e.g. B. the spatial possibilities of the nozzle, which is why heaters with a steeply inclined bottom usually have a square or round nozzle with the above defects (large droplet, high gas velocities, large pressure drop). This disadvantage degrades the properties of a steeply sloping floor to such an extent that most gasification furnace manufacturers prefer a level or slightly sloping floor (5-10°). The disadvantage of these floor types is that the ash does not flow through the nozzle into the combustion chamber and accumulates at the bottom of the gasification chamber. This reduces the quality of combustion and puts a strain on the operator (heating has to be switched off regularly and the ash removed).

In summary, existing gasification furnace nozzles have many shortcomings, the proportion of which varies depending on the type and size of the mold and the slope (degree of slope) of the bottom. These shortcomings are especially pronounced in heaters with a sloping bottom.

The deficiencies of known gasifier-heater-nozzle solutions are completely or largely eliminated by a solid fuel gasifier-heater with a radial nozzle containing a gasification chamber and a combustion chamber located below the gasification chamber. The floor of the gasification chamber is inclined towards the center of the gasification chamber by four inclined walls forming a pyramid shape form with the tip pointing into the combustion chamber, or forms a trough. The gasification chamber and the combustion chamber are separated by a partition through which the nozzle passes. The inlet opening is in the bottom of the gasification chamber and the outlet opening is in the wall of the combustion chamber. The essence of the invention is that the inlet opening of the nozzle consists of a central slit in the shape of a rectangle or square and radial slits forming four rectangular openings. These are located in the rims between the sloping walls of the floor of the gasification chamber, creating a radial pattern. The central vent of the nozzle is routed under the central slot. The radial slots are followed by ducts which open into the central vent which forms an exit opening in the walls of the combustion chamber. The channels are at an angle of at least 40°, ie the angle from the bottom of the channels relative to the horizontal plane. The side walls of the channels are mutually open to their lower walls (bottom of the channels).

• Dank der radialen Form und der diagonalen Anordnung hat der Einlassbereich eine 2 - 3x größere Fläche als eine gleich breite rechteckige Düse, die traditionell im mittleren Teil des Bodens (d. h. parallel zur Seitenwand der Vergasungskammer) angeordnet ist.
• Das Austrittsloch konzentriert die Rauchgase zu einem kompakten Strom, was die Homogenität der Gase und die Qualität der Verbrennung erhöht.
• Die Geometrie der Düse erlaubt den Einsatz von Keramik (die Teile zwischen den einzelnen Balken sind ausreichend massiv).
• Der große Querschnitt der Düse reduziert den Druckverlust, was die Leistung des Ventilators reduziert und sogar den Betrieb nur mit dem natürlichen Schornsteinzug ermöglicht.
• Der Abfall eines Teils des Kraftstoffs ist deutlich kleiner als bei Düsen mit quadratischer oder kreisförmiger Eintrittsöffnung (von gleicher Fläche), die vorhandenen Heizungen mit einem deutlich abfallenden Boden haben.

The advantages of the invention are:

• Thanks to the radial shape and diagonal arrangement, the inlet area has a 2 - 3x larger area than a rectangular nozzle of the same width, which is traditionally located in the central part of the bottom (ie parallel to the side wall of the gasification chamber).
• The exit hole concentrates the flue gases into a compact stream, which increases the homogeneity of the gases and the quality of the combustion.
• The geometry of the nozzle allows the use of ceramics (the parts between the individual bars are sufficiently solid).
• The large cross-section of the nozzle reduces the pressure loss, which reduces the fan's performance and even allows operation with only the natural chimney draft.
• The drop of part of the fuel is significantly smaller than in nozzles with a square or circular entrance opening (of the same area), which have existing heaters with a significantly sloping bottom.

Fig. 1

ein Seitenteil eines Vergasungserhitzers mit stark geneigtem Boden mit Radialdüse,

Fig. 2

eine dimensionale Ansicht einer Vergasungskammer mit quadratischem Querschnitt und pyramidenstumpfförmigem Schrägboden,

Fig. 3

eine dimensionale Ansicht einer Düse in einem Vergaserheizer mit einer Vergasungskammer mit quadratischem Querschnitt,

Fig. 3.1

eine Draufsicht auf die Düse aus Fig. 3,

Fig. 3.2

einen Schnitt A-A orientiert an Fig. 3.1,

Fig. 3.3

eine Unteransicht der Düse aus Fig. 3,

Fig. 4

eine räumliche Darstellung der Düse und Teile der Düse aus Fig. 3,

Fig. 5

eine räumliche Darstellung der Düsenkanäle aus Fig. 3,

Fig. 6

eine räumliche Darstellung der zentralen Entlüftung der Düse aus Fig. 3,

Fig. 7

eine räumliche Darstellung der Eingangsöffnung aus Fig. 3,

Fig. 8

einen Schnitt B-B orientiert an Fig. 3.1, der die Form des Kanals zeigt,

Fig. 9

eine räumliche Darstellung des Kanals aus Fig. 3,

Fig. 10

eine dreidimensionale Ansicht einer Vergasungskammer mit rechteckigem Querschnitt und schrägem, wannenförmigem Boden,

Fig. 11

eine Raumansicht einer Düse in einem Vergaserheizer mit einer im Querschnitt rechteckigen Vergasungskammer

Fig. 11.1

eine Draufsicht auf die Düse aus Fig. 11,

Fig. 11.2

einen Schnitt A-A orientiert an Fig. 11.1,

Fig. 11.3

eine Unteransicht der Düse aus Fig. 11,

Fig. 12

eine räumliche Darstellung der Düse und Teile der Düse aus Fig. 11,

Fig. 13

eine räumliche Darstellung der Düsenkanäle aus Fig. 11,

Fig. 14

eine räumliche Darstellung der zentralen Entlüftung der Düse aus Fig. 11 und

Fig. 15

eine räumliche Darstellung der Eintrittsöffnung der Düse aus Fig. 11.

The invention is explained in more detail with reference to the accompanying figures. Show it:

1

a side part of a gasification heater with a steeply inclined bottom with a radial nozzle,

2

a dimensional view of a gasification chamber with a square cross-section and a truncated pyramid-shaped sloping floor,

3

a dimensional view of a nozzle in a gasifier heater with a square cross-section gasification chamber,

Figure 3.1

a top view of the nozzle 3 ,

Figure 3.2

a section AA oriented to Figure 3.1 ,

Figure 3.3

a bottom view of the nozzle 3 ,

4

a spatial representation of the nozzle and parts of the nozzle 3 ,

figure 5

a spatial representation of the nozzle channels 3 ,

6

a spatial representation of the central vent of the nozzle 3 ,

7

a spatial representation of the entrance opening 3 ,

8

a cut BB oriented to Figure 3.1 , showing the shape of the canal,

9

a spatial representation of the channel 3 ,

10

a three-dimensional view of a gassing chamber with a rectangular cross-section and a sloping, trough-shaped floor,

11

a spatial view of a nozzle in a gasifier heater with a gasification chamber rectangular in cross-section

Figure 11.1

a top view of the nozzle 11 ,

Figure 11.2

a section AA oriented to Figure 11.1 ,

11.3

a bottom view of the nozzle 11 ,

12

a spatial representation of the nozzle and parts of the nozzle 11 ,

13

a spatial representation of the nozzle channels 11 ,

14

a spatial representation of the central vent of the nozzle 11 and

15

a spatial representation of the inlet opening of the nozzle 11 .

1 shows a gasification heater 100 (gasification boiler) for the manual addition of solid fuel 6, for example wood.

The gasification boiler 100 includes a gasification chamber 4 with a square or rectangular cross-section and a combustion chamber 9 arranged below the gasification chamber 4. The gasification chamber 4 and the combustion chamber 9 are separated by a partition wall 5 which forms the bottom 10 of this gasification chamber 4 on the side of the gasification chamber 4 , and the combustion-side chambers 9 form the upper inner wall 7 of this combustion chamber.

Through the partition 5 is a nozzle 2, consisting of an inlet opening 1 and an outlet opening 3 out. The bottom 10 of the gasification chamber 4 is inclined significantly towards the center of the gasification chamber 4 by four inclined walls 11. The walls 11 of the gasification chamber 4, which is square in cross section, are inclined in the form of a pyramid ( 2 ). The inclined walls 11 of the gasification chamber 4 of rectangular section are inclined in the form of a trough ( 10 ).

The inlet opening 1 of the nozzle 2 on the gasification chamber 4 with a square cross-section ( Figures 3 to 9 ) contains a square central slot 13 and radial slots 14. Below the central slot 13 is a central vent 15 forming an exit opening 3 in the wall 7 of the nozzles 2 of the combustion chamber 9. The central vent 15 is in the form of a regular prism with a square profile, the upper part of which has folded corners. The radial slots 14 are formed by rectangular openings located in the edges 12 of the bottom 10 of the gasification chamber 4 . This will create a radial pattern generated that resembles a four-pointed star or a cross. The channels 8 leading to the central vent 15 are connected to the radial slots 14 through the nozzles 2. The channels 8 are inclined to the central vent 15 at an angle of at least 40°. The side walls 16 of the channels 8 are mutually open to their lower walls 17 ( Figures 8 and 9 ).

The inlet opening 1 of the nozzle 2 on the gasification chamber 4 (which is rectangular in cross-section Figures 11 to 15 , 8 and 9 ) contains a central slit 13 of rectangular shape and radial slits 14. Below the opening 15, a central vent 15 with a central slit 13 is guided, which forms a combustion chamber wall 7,9. The combustion chamber wall 7, 9 has an outlet opening 3 and 2 nozzles. The central vent 15 has a variable size rectangular profile. The radial slots 14 are formed by rectangular openings located in the edges 12 of the bottom 10 of the gasification chamber 4 creating a radial pattern. The channels 8 leading to the central vent 15 are connected to the radial slots 14 through the nozzles 2. The channels 8 are inclined to the central vent 15 at an angle of at least 40°. The side walls 16 of the channels 8 are mutually open to their lower walls 17 ( Figures 8 and 9 ).

Reference List

• 1 - entrance hole
• 2 - nozzle
• 3 - outlet hole
• 4 - gasification chamber
• 5 - bulkhead
• 6 - fuel
• 7 - wall
• 8 - channel
• 9 - combustion chamber
• 10 - below
• 11 - sloping wall
• 12 - edge
• 13 - center gap
• 14 - radial gap
• 15 - central vent
• 16 - side wall
• 17 - lower wall
• 100 - heating

Claims (1)

Heating apparatus for solid fuel gasifiers with a radial nozzle, a gasification chamber (4) with a bottom (10), a combustion chamber (9) arranged below the gasification chamber, the bottom (10) of the gasification chamber (4) being inclined towards its center and surrounded by four sloping walls ( 11) forming a pyramid shape with the tip pointing towards the combustion chamber (9) or a trough shape, while the gasification chamber (4) and the combustion chamber (9) are separated by a partition wall (5) placed on the side of the gasification chamber (4 ) forms the bottom (10) of this gasification chamber and, on the combustion chamber (9) side, the upper inner wall (7), while the partition (5) is guided by the nozzle (2), the inlet opening (1) of which is in the bottom of the gasification chamber ( 4) and whose outlet opening (3) is formed in the inner wall (7) of the combustion chamber (9),
characterized, that the inlet orifice (1) of the nozzle (8) consists of a central slot (13) of rectangular or square shape and of radial slots (14) of rectangular shape made in the edges (12) between the sloping walls (11) of the bottom (10) of the gasification chamber (4) are formed, that under the central slot (13) the central ventilation (15) of the nozzle (2) is guided in the form of a through hole, that the slots (14) radially connect channels (8) leading to the central vent (15), and that the outlet opening (3) is formed in the inner wall (7) of the combustion chamber (9), while the channels (8) are inclined towards the central vent (15) at an angle of at least 40° and the side walls (16) of the channels (8) mutually open towards their lower walls (17).

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