EP3263987A1 - Device and method for the combustion of combustible gases - Google Patents

Abstract

Disclosed is a device for burning combustible gases. The device comprises a combustion chamber bounded by a combustion chamber and a burner, which is arranged in a recess of the combustion chamber wall. The burner is designed as a parallel flow burner and a gas inlet opening of the burner is directed tangentially against the combustion chamber wall.

Description

TERRITORY

The present invention relates to the field of combusting combustible gases for heat recovery. In particular, the present invention relates to a combustion chamber for burning combustible gases obtained by means of biomass gasification for supplying heat to a heat engine.

BACKGROUND

A gas stream, and in particular a gas stream produced by gasification of biomass, may carry with it substances and compounds which, after burning the combustible gases, remain as residues and deposit on plant elements. However, the residues may reduce the efficiency of heat transfer elements provided in the combustion chamber or in a passage adjacent the combustion chamber for exhausting the hot gases generated during combustion. Furthermore, corrosion damage can be caused by aggressive deposits on system elements.

Desirable are thus devices and methods for burning combustible gases, which reduce the amount of residues remaining after the combustion of the combustible gases and are also as insensitive as possible to the deposition of residues. Furthermore, devices and methods for combusting combustible gases are generally advantageous if they have high efficiency.

SUMMARY

At least some of these advantageous (process) properties are achieved by a device according to the invention for combusting combustible gases, a system according to the invention and a method according to the invention for combusting combustible gases.

The combustible gas combusting apparatus of the present invention includes a combustion chamber defined by a combustion chamber wall and a burner disposed in a recess of the combustion chamber wall, the burner being formed as a parallel flow burner and a gas inflow port of the burner being directed tangentially against the combustion chamber wall.

For the purposes of the present invention, the term "parallel flow burner" is understood in particular to mean a burner in which flammable gases and oxygen (or oxygen-containing gas mixtures such as air) are conducted parallel to one another into the combustion chamber, the mixture of combustible gases and the oxygen in the combustion chamber takes place. Furthermore, for the purposes of the present invention, the term "gas inflow opening" is understood to mean, in particular, an outlet of a gas supply line, through which combustible gases are conducted into the combustion chamber. At a sufficient flow rate at the outlet of the gas supply line, by means of suitable design means, for example by deflecting plates projecting into the gas flow, a turbulent gas flow can be generated, which ensures an accelerated mixing of the combustible gases and oxygen and, in addition, an improved heat transfer.

Furthermore, for the purposes of the present invention, the expression "directed tangentially against the combustion chamber wall" is understood to mean an orientation of the gas inflow opening in which an average flow direction of the gas flow conducted into the combustion chamber through the gas inflow opening is not directed toward the center of the combustion chamber or in one Symmetrieebene the combustion chamber is located. Rather, in the context of the present invention, the expression "directed tangentially against the combustion chamber wall" means, in particular, such an orientation of the gas inflow opening which is inclined away from the center of the combustion chamber or with a plane of symmetry of the combustion chamber which, for example, runs through the center of the recess , an angle greater than 15 °, greater than 30 ° or greater than 45 °. The tangential orientation of the gas inflow opening against the combustion chamber wall, or onto a region on the inside of the combustion chamber wall, thus generates a deflection of the turbulent gas flow along the inner contour of the combustion chamber wall. For example. creates the tangential orientation of the Gaseinströmungsöffnung against a wall region of a rotationally symmetrical combustion chamber portion a rotational component of the turbulent gas flow about the axis of symmetry.

Preferably, the combustion chamber wall has a cylindrical or frustoconical portion in the center of which a heat transfer element extends in the axial direction.

Due to the tangential orientation of the gas inflow opening, a turbulent gas flow is generated which is not directed directly at the heat transfer element, but flows around the heat transfer element along a path that winds around the heat transfer element. As a result, the combustion chamber wall can be heated over a large area so that a considerable part of the heat is transmitted by radiation from the combustion chamber wall to the heat transfer element. Thus, heat can be applied more uniformly to the heat transfer member (than to a gas inflow port directly directed to the heat transfer member), and further damage caused by fatigue can be reduced. Further, deposits on the heat transfer member and occurrence of high temperature corrosion are reduced because the flame is not concentrated on the heat transfer member but on the combustion chamber wall. In addition, due to the centrifugal force resulting from the rotational component, substances and compounds which carry the hot gases produced during combustion are transported toward the combustion chamber wall, which further reduces the amount of deposits on the heat transfer element

Preferably, the heat transfer element has a cylindrical or frusto-conical base body, which is provided with a number of ribs extending in the radial direction and spaced apart from one another in the axial direction, or with a rib that spirals around the main body.

By providing one or more ribs, the surface area and thus the heat transfer capability of the heat transfer element can be increased. Further, by the arrangement and shape of the rib (s) of the gas flow path and / or the mixing or the expansion of the turbulent gas flow are controlled or adapted to different processes.

Preferably, the device has a second recess spaced from the recess in the axial direction, the second recess being adapted and provided for discharging hot gases generated in operation by combustion of the combustible gases in the combustion chamber.

By the axially spaced second recess for discharging the hot gases is achieved that the gas flow is guided spirally around the heat transfer element, whereby this even more uniform over an entire (axial) length of the heat transfer element can be subjected to heat.

Preferably, the apparatus comprises a heat engine coupled to the heat transfer element.

By reducing the amount of deposits and the uniform loading of the heat transfer element with heat, a consistently efficient and low-maintenance operation of the heat engine can be achieved.

Preferably, the apparatus comprises a controller adapted to control a flow of gas through the gas inflow port, the inflowing gases moving in a helical path around the heat transfer member.

The controller thereby makes it possible, by increasing or decreasing the velocity of the incoming gas flow, to control the turbulence and residence time of the combustible gases in the combustion chamber, thereby controlling the degree of mixing of the gases and the efficiency of the heat transfer.

Preferably, the combustion chamber wall is at least partially lined with a refractory material, particularly preferably with ceramic material or a chamotte.

The lining of the combustion chamber wall can, for example, be done by tiling with provided between the tiles expansion joint, the tiles on the Inside with ceramic and on the outside are additionally provided with a (non-ceramic) heat insulation. It can thereby be achieved that heat induced material fatigue damage to the combustion chamber wall is avoided and a majority of the heat transferred to the combustion chamber wall is not transmitted to the outside but as radiant heat to the heat transfer element. In addition, corrosion damage can be avoided or at least reduced.

The system according to the invention comprises the device for combusting combustible gases and a biomass gasification device operable in countercurrent mode, the burner being connected to the biomass gasification device which can be operated in the countercurrent process.

Due to the robustness of the combustion chamber can be burned by gasification of biomass in countercurrent gas flow produced without additional filtering or cleaning, whereby the use of fossil fuels can be reduced or replaced by renewable resources, without significantly increasing the maintenance of the combustion chamber.

The combustible gas combustion method of the present invention comprises flowing the combustible gases into a combustion chamber through a gas inflow port, combusting the combustible gases, and discharging hot gases from the combustor resulting from the combustion, wherein a wall of the combustor is at least partially lined with a refractory material is and the combustible gases are guided from the gas inlet opening along a spiral path through the combustion chamber.

The guiding of the combustible gases from the gas inlet opening along a spiral path through the combustion chamber thereby allows an increased residence time of the combustible gases in the combustion chamber and thus assists the combustion of the combustible gases in the combustion chamber as complete as possible. By providing a lining with refractory material, improved resistance to high temperatures and temperature variations, and in the case of a ceramic lining or a lining with a chamotte, also a high resistance against deposition-induced corrosion and in the case of a ceramic lining a good thermal insulation of the combustion chamber achieved.

Preferably, the combustion chamber wall has a cylindrical or frustoconical portion in the center of which a heat transfer element extends in the axial direction.

The hot gases generated by the combustion thus spiral around the heat transfer element. As a result, the combustion chamber wall is heated over a large area to temperatures at which a significant portion of the heat is transmitted by radiation from the combustion chamber wall to the heat transfer element, whereby the heat transfer element is uniformly applied with heat. In addition, the residues resulting from the firing are accelerated away from the heat transfer member in the direction of the refractory or fireclay wall, thereby reducing the amount of deposits on the heat transfer member and maintaining the thermal conductivity of the heat transfer member surface.

Preferably, the heat transfer element has a cylindrical or frusto-conical base body, which is provided with a number of ribs extending in the radial direction and spaced apart from one another in the axial direction, or with a rib that spirals around the main body.

By providing one or more ribs, the surface area and thus the heat transfer capability of the heat transfer element can be increased. Furthermore, the gas flow path and / or the mixing of the gas flow can be adjusted or adapted to different processes by the arrangement and shape of the rib (s).

Preferably, the hot gases produced during combustion are removed from the combustion chamber through a recess which is spaced apart from the gas inlet opening in the axial direction.

Preferably, the method further comprises transferring heat from the heat transfer element to a process fluid of a heat engine.

Preferably, the method further comprises operating a countercurrent biomass gasification apparatus and passing the combustible gases generated in the gasification from the biomass gasification apparatus through the gas inflow port into the combustor.

Due to the robustness of the combustion chamber thus generated by the gasification of biomass gas stream can be directly burned without additional purification, whereby the use of fossil fuels can be reduced or replaced by renewable resources.

Preferably, the biomass gasification apparatus is a biomass pellet or biomass chaff gasifier, and comprises operating the biomass pellet or biomass chaff gasifier countercurrently by passing flue gases through a pellet bed or a wood chip bed.

By passing the combustible gases through the pellet bed or the wood chip bed, some of the substances and compounds forming during combustion can be filtered out of the gas stream.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

einen Längsschnitt einer ersten Vorrichtung gemäß einer bevorzugten Ausführungsform der vorliegenden Erfindung;

Fig. 2

einen Querschnitt der ersten Vorrichtung;

Fig. 3

einen Längsschnitt einer zweiten Vorrichtung gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung;

Fig. 4

einen Querschnitt der zweiten Vorrichtung;

Fig. 5

einen Längsschnitt eines in der ersten oder zweiten Vorrichtung einsetzbaren Wärmeübertragungselements, an das eine Wärmekraftmaschine gekoppelt ist;

Fig. 6

eine schematische Darstellung eines Systems gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung; und

Fig. 7

ein Flussdiagramm eines Prozesses zur Verfeuerung brennbarer Gase zeigt.

The invention will be explained in more detail in the detailed description on the basis of exemplary embodiments, reference being made to drawings in which:

Fig. 1

a longitudinal section of a first device according to a preferred embodiment of the present invention;

Fig. 2

a cross section of the first device;

Fig. 3

a longitudinal section of a second device according to another preferred embodiment of the present invention;

Fig. 4

a cross section of the second device;

Fig. 5

a longitudinal section of a usable in the first or second device heat transfer element to which a heat engine is coupled;

Fig. 6

a schematic representation of a system according to another preferred embodiment of the present invention; and

Fig. 7

a flowchart of a process for combusting combustible gases shows.

The same elements in the drawings by identical reference numerals and analogous elements with an apostrophe supplemented but otherwise identical reference numerals.

DETAILED DESCRIPTION

Fig. 1 and 2 show a longitudinal section and a cross section of a first device 10 according to a preferred embodiment of the present invention along the cutting planes BB and AA. The device 10 comprises a rotationally symmetrical combustion chamber 12, the interior of which is limited to the outside by a combustion chamber wall 14. In a recess 16 of the combustion chamber wall 14, a burner 18 is arranged. The burner 18 is fed by a first supply line 20 with combustible gases and by a second supply line 22 with oxygen or ambient air. As in the Fig. 1 and 2 As shown, the first supply line 20 may be concentrically disposed in the second supply line 22. Furthermore, the first supply line 20 may be arranged parallel to but outside the second supply line 22.

As in Fig. 2 shown, the gas inflow opening 24 of the burner 18 is inclined away from the center of the combustion chamber 12 and directed tangentially against an inner side of the combustion chamber wall 14, wherein an average flow direction of a flowing out of the burner 18 gas flow with a mirror symmetry plane of the combustion chamber through the center of the recess 16 at an angle of more than 45 °. The gas inlet opening 24 of the burner 18 is further provided with projecting into the gas flow baffles 26, which at a corresponding gas inflow rate, which can be controlled, for example, by an ambient air supply control, provide for the occurrence of flow vortices in the gas flow. The flow vortices mix the combustible gases and the oxygen in the combustion chamber 12 immediately after exiting the gas inflow opening 24. The gas flow is thus impressed, in addition to a rotational movement component about the combustion chamber longitudinal axis, local flow vortices, which decrease along the path of the gas flow in expansion and number.

In the center of a cylindrical portion 28 of the combustion chamber wall 14, a heat transfer member 30 extends in the axial direction. The heat transfer element 30 has a cylindrical base body 32, which comprises a conduit 34 filled with a process fluid. In this connection, however, it should be noted that the shape of the portion 28 and the heat transfer member 30 is not limited to the cylinder shape. Rather, for example, the heat transfer element 30 may have a differently shaped, preferably rotationally symmetrical base body 32 instead of the cylindrical base body 32, z. B. a frustoconical base body 32nd

In operation, the heat generated during combustion in the combustion chamber 12 is transferred (radially inward) to the process fluid by the heat transfer element 30 by the heat transfer element 30 forming a homogeneous thermal connection or bridge between the interior of the combustion chamber 12 and the process fluid. By contrast, a transfer of heat to a process fluid (in the radial outward direction) through the combustion chamber wall 14, for example through an inwardly concave heat transfer device arranged in a further recess of the combustion chamber wall 14, which limits the combustion chamber 12 to the outside, is not provided. Rather, the combustion chamber wall 14 may be lined with a refractory material, for example. With ceramic material in the form of (inside concave) ceramic tiles or with a chamotte to the insulation of the combustion chamber 12. The ceramic tiles or chamotte emit a portion of the absorbed heat as radiant heat to the heat transfer element 30, which transfers the heat to the process fluid provided in the channel 34. The channel 34 may, as in Fig. 1 indicated to be a portion of a heating circuit, wherein the on the Process fluid transmitted heat with the channel 34 flowing through the process fluid can be forwarded.

The combustion chamber wall 14 also has, in a conically tapering section, a second recess 36, which is spaced from the first recess 16 in the axial direction, the axial direction preferably coinciding with the vertical and the second recess 36 being arranged above the first recess 16. The hot gas flow generated by burning the combustible gases is thereby imparted next to the rotational movement component a linear movement component in the direction of the second recess 36, whereby the gas flow along a spiral path (in Fig. 1 and 2 indicated by "flow arrows") is moved from the gas inlet opening 24 to the second recess 36 and is discharged there from the combustion chamber 12.

3 and 4 show a longitudinal section and a cross section of a second device 10 'according to another preferred embodiment of the present invention along the cutting planes DD and CC. Like from the 3 and 4 As can be seen, the device 10 'differs from the device 10 in that the hot gases through the second recess 36' not as in the second recess 36 in Fig. 1 and 2 , in the axial direction, but in the tangential direction from the combustion chamber 12 'are discharged. In this case, a discharge channel which adjoins the second recess 36 'and which extends in the radial direction can enclose a predetermined angle with a plane of symmetry of the combustion chamber 12' through the middle of the second recess 36 ', which is, for example, greater than 15 °, larger than 30 ° or greater than 45 °. Like from the Fig. 2 and 4 As can be seen, the orientation of the gas inflow opening 24 and the orientation of the discharge channel relative to the respective radial direction through the center of the first recess 16 and through the center of the second recess 36 'about the respective axial direction through the center of the first recess 16 and through the center of the second recess 36 'tiltsgegesinnig tilted. As a result, the orientation of the discharge channel is adapted to the spiral path of the gas flow.

The heat transfer element 30 may, as in Fig. 5 shown, a series of radially extending and spaced apart in the axial direction spaced ribs 38 or (parallel to the gas flow) spirally around the body 32 spiral rib 38 have. Furthermore, the heat transfer element 30 may be coupled to a heat engine 40. This can, as in Fig. 5 shown, a working piston 42 may be provided in the heat transfer member 30, which is displaced by the expanding process fluid while doing work. Further, in the heat transfer element 30, a displacer 44 may be provided, which displaces the process fluid in the channel 34 from a warmer to a colder channel region, whereby the process fluid cools and the working piston 42 returns to its original position. For example. This can be used to implement a Stirling process that drives a generator.

Fig. 6 schematically shows a biomass gasification device 46 which is adapted for operation in countercurrent process and is further adapted to supply the device 10 with combustible gases. The biomass gasification apparatus 46 includes a biomass feed 48 and an ambient air feed 50 connected at opposite ends of a reactor space of the biomass gasification apparatus 46. The combustible gases generated during the gasification are filtered when flowing through the biomass, for example. When flowing through a biomass pellet bed (such as a Holzpelletschüttung) or a Biomassehackgutschüttung and passed through the first supply line 20 into the combustion chamber 12. Furthermore, ambient air is conducted into the combustion chamber 12 via the second supply line 22. The hot gases generated during the combustion of the combustible gases in the combustion chamber 12 release heat to the heat transfer element 32 and are discharged via a flue gas channel 52. In the flue gas channel 52, a heat exchanger may further be provided which extracts heat from the hot gases and supplies them to a heating circuit.

Fig. 7 11 shows a flowchart of the combustible gas combustion process 54 in the combustor 12. The process 54 includes flowing the combustible gases 56 into the combustor 12 through the gas inflow port 24 and passing the combustible gases along a spiral path through the combustor 12. Further For example, the process 54 includes firing 60 the combustible gases (along the spiral path) and discharging 62 the hot gases from the combustor 12 resulting from firing.

LIST OF REFERENCE NUMBERS

10, 10 '

device

12, 12 '

combustion chamber

14, 14 '

combustion chamber wall

16

recess

18

burner

20

first supply line

22

second supply line

24

gas introducing

26

baffles

28

cylindrical section

30

Heat transfer element

32

body

34

channel

36, 36 '

recess

38

rib

40

Heat engine

42

working piston

44

displacer

46

Biomass gasifier

48

biomass supply

50

Ambient air supply

52

Flue

54

Verfeuerugsprozess

56-62

process steps

Claims (15)

Apparatus (10, 10 ') for combusting combustible gases, comprising: one of a combustion chamber wall (14, 14 ') limited combustion chamber (12, 12'); and a burner (18) disposed in a recess (16) of the combustion chamber wall (14, 14 '); characterized in that the burner (18) is designed as a parallel flow burner and a gas inlet opening (24) of the burner (18) is directed tangentially against the combustion chamber wall (14, 14 '). The combustible gas combustor (10, 10 ') according to claim 1, wherein the combustor wall (14, 14') has a cylindrical or frusto-conical portion (28) in the center of which a heat transfer member (30) extends in the axial direction. The combustible gas combusting apparatus (10, 10 ') according to claim 2, wherein the heat transferring member (30) has a cylindrical or truncated cone-shaped main body (32)
a series of ribs (38) extending in the radial direction and spaced apart from one another in the axial direction; or
is provided with a spiraling around the base body rib (38). The combustible gas combusting apparatus (10, 10 ') according to claim 2 or 3, wherein said apparatus (10, 10') has a second recess (36, 36 ') is spaced from the recess (16) in the axial direction, wherein the second recess (36, 36 ') for discharging hot gases, which are generated in operation by a burning in the combustion chamber (12, 12') combustion of the combustible gases, established and is provided. A combustible gas combustor (10, 10 ') according to any of claims 2 to 4, further comprising a heat engine (40), said heat engine (40) coupled to said heat transfer member (30). The combustible gas combustor (10, 10 ') of any one of claims 2 to 5, further comprising a controller, the controller configured to control gas flow through the gas inflow port (24), the inflowing gases being in a spiral Move web around the heat transfer element (30). Device (10, 10 ') for combusting combustible gases according to one of claims 1 to 6, wherein the combustion chamber wall (14, 14') is at least partially lined with a refractory material, preferably with ceramic material or a chamotte. System comprising: an apparatus (10, 10 ') for combusting combustible gases according to any one of claims 1 to 7; and a biomass gasification apparatus (46) operable in countercurrent mode; wherein the burner (18) is connected to the countercurrent-operable biomass gasification device (46). A method (54) of combusting combustible gases comprising: Flowing (56) the combustible gases into a combustion chamber (12, 12 ') through a gas inflow port (24); Burning (60) the combustible gases; and Discharging (62) hot gases generated during combustion from the combustion chamber (12, 12 '); characterized in that a wall (14, 14 ') of the combustion chamber (12, 12') is at least partially lined with a refractory material; and the combustible gases are guided (58) from the gas inlet opening (24) along a spiral path through the combustion chamber (12, 12 '). A combustion gas combusting method (54) according to claim 9, wherein said combustion chamber wall (14, 14 ') has a cylindrical or frusto-conical portion (28) in the center of which a heat transfer member (30) extends in the axial direction. The flammable gas combusting method (54) of claim 10, wherein the heat transfer member (30) comprises a cylindrical or frusto-conical body (32)
a series of ribs (38) extending in the radial direction and spaced apart from one another in the axial direction; or
is provided with a spiraling around the main body (32) winding rib (38). The flammable gas combusting method (54) according to claim 10 or 11, wherein the hot gases generated during firing are exhausted from the combustion chamber (12) through a recess (36) spaced from the gas inflow port (24) in the axial direction. The combustible gas combustion method (54) of any one of claims 10 to 12, further comprising: Transferring heat from the heat transfer element (30) to a process fluid of a heat engine (40). The combustible gas combustion method (54) of any one of claims 9 to 13, further comprising: Operating a biomass gasification device (46) in countercurrent process; and Passing the combustible gases generated in the gasification from the biomass gasification device (46) through the gas inflow port (24) into the combustion chamber (12, 12 '). The combustible gas combusting method (54) of claim 14, wherein the biomass gasification apparatus (46) is a biomass pellet or biomass chaff gasifier, and operating the biomass pellet or biomass chaff gasification apparatus comprises countercurrent flow of flue gases through a pellet bed or a wood chip bed.

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