DE102024108127A1 - New pyrolysis gas boiler and process for generating pyrolysis gas - Google Patents

Abstract

The present invention provides a pyrolysis gas boiler (10) that eliminates the problems of known pyrolysis gas boilers. Above all, the pyrolysis gas boiler (10) according to the invention is technically not very complex and thus less susceptible to damage. Very little tar and other undesirable reaction products are produced, and in particular, the pyrolysis gas produced is very pure.

Description

The present invention relates to a pyrolysis gas boiler, in particular for wood, according to the preamble of claim 1 and a method for producing pyrolysis gas according to the preamble of claim 14.

Such pyrolysis gas boilers for wood and similar organic materials (hereinafter referred to as “fuels”), such as loose or briquetted wood chips, bamboo, miscanthus, sugar cane, brushwood, or similar organic material in a single or mixed composition, as well as optional admixtures of dried biomass from sewage treatment plant residues or animal manure, hereinafter also referred to as “wood gas boilers,” particularly those consisting of an oxidation zone and a reduction zone, are known in numerous designs, with recent emphasis on the cleanest and tar-free gasification possible. These include, among others, the documents DE 10 2009 042 104 A1 , DE 10 2021 002 475 A1 , DE 10 2021 002 478 A1 , DE 10 2021 002 657 A1 , DE 10 2021 002 658 A1 and DE 20 2021 001 720 U1 .

The disadvantage of these solutions is that they are usually technically very complex and therefore vulnerable, so that their longevity and freedom from maintenance suffer, which is why these pyrolysis gas boilers often cannot be operated very economically.

The object of the present invention is therefore to provide a solution that eliminates at least some of the problems of known pyrolysis gas boilers. The pyrolysis gas boiler should preferably be technically less complex and thus less susceptible to failure. In particular, as little tar and other undesirable reaction products as possible should be produced, and the pyrolysis gas produced (e.g., wood gas) should preferably be very pure.

This object is achieved with the pyrolysis gas boiler according to the invention according to claim 1 and the method according to the invention for generating pyrolysis gas according to claim 14. Advantageous further developments are specified in the dependent claims and in the following description together with the figures.

The inventors recognized that this problem can be solved in a surprising way and particularly easily if the pyrolysis gas boiler contains means for comminuting and, if necessary, mixing fuel coal, such as charcoal, and/or fuel, such as wood and similar organic materials, such as loose or briquetted wood chips, bamboo, miscanthus, sugar cane, brushwood, or similar organic material in a single or mixed composition, as well as optional admixtures of dried biomass from sewage treatment plant residues or animal dung, in particular the charcoal produced in the pyrolysis zone, because this homogenizes the fuel and/or fuel coal charge, which overall leads to clean gasification and thus to less tar formation and a cleaner pyrolysis gas, e.g., wood gas. Carbonized fuels are referred to below as "fuel coal," with one example being charcoal.

The pyrolysis gas boiler according to the invention with a boiler housing and a grate for generating pyrolysis gas by pyrolysis of fuel in a bed of embers above the grate, wherein inside the pyrolysis gas boiler there are means for supplying air and means for discharging the generated pyrolysis gas from the pyrolysis gas boiler, wherein in the boiler housing there is a central axis of rotation for one or more elements of the pyrolysis gas boiler, wherein the central axis of rotation is arranged parallel to the vertical longitudinal extent of the pyrolysis gas boiler, is characterized in that inside the pyrolysis gas boiler there are means for at least partially comminuting fuel and/or fuel coal.

These comminution means are preferably arranged between the grate and the air supply means, particularly in the pyrolysis zone of the pyrolysis gas boiler for comminution of fuel undergoing the pyrolysis process, because this homogenization is particularly effective for gasification. Above all, this allows the comminuted fuel particles (e.g., wood particles) to be fed into a gasification pan.

In an advantageous development, a filter with an upward-facing filter surface is provided inside the pyrolysis gas boiler. The filter is surrounded by a frame located on the boiler housing, with a gap between the filter and the frame. The filter is preferably an additional grate. This filter allows for the efficient removal of ash and coal from the oxidation zone and the collection of coarse fuels (e.g., wood) or fuel coal residues (e.g., charcoal residues) still to be gasified.

In an advantageous further development, it is provided that elevations exist on the filter surface, which are preferably arranged radially on the outside of the filter near the circumference of the filter. This results in particularly effective comminution. Extinguishing glowing fuel (e.g. wood) or fuel coal residues (e.g. charcoal residues).

In an advantageous development, at least one stirring means is arranged above the filter surface, movable relative to the filter surface, wherein the stirring means is preferably star-shaped with respect to the central axis of rotation. This stirring means ensures very effective ash and ember removal through the filter and, at the same time, very effective mixing and homogenization of the fuel (e.g., wood) and fuel coal (e.g., charcoal) bed.

In an advantageous further development, radial projections are arranged on the filter and/or the filter frame with respect to the central axis of rotation, wherein such projections preferably extend over the entire vertical height of the filter and/or the frame. These projections can, but do not have to, be vertically continuous; they can thus also be arranged offset. These projections ensure particularly effective comminution of fuel (e.g., wood) or fuel coal residues (e.g., charcoal residues) in the intermediate space. This also prevents the intermediate space from becoming clogged, which can occur, for example, due to foreign matter contained in the wood.

In an advantageous further development, the filter is designed to be rotatable relative to the frame. This ensures particularly effective shredding and also ensures excellent ash and ember drainage.

In an advantageous refinement, slots are arranged in the filter surface. These slots allow ash and embers to be removed particularly effectively.

If the slots have at least two different widths over their radial extent, in particular if they are wider radially on the outside than radially on the inside, then larger fuel (e.g. wood) and ember particles are guided outwards and then released downwards, which improves the working through of the ember bed.

If the slots are radially inclined, especially if they are curved, then the ash is processed particularly effectively, which is further improved when the filter rotates around the central axis of rotation.

If the slots in groups are aligned in the same way, in particular there being at least two groups which are arranged adjacently, the slots of one group being aligned differently to the slots of the other group, the slots of one group preferably running radially outwards in a clockwise direction and the slots of the other group running radially outwards in an anti-clockwise direction, then the filter surface is designed to be particularly stable and durable even at high temperatures, so that the filter does not melt out.

In an advantageous further development, the central axis of rotation comprises a vertical drive shaft that is designed to be vertically displaceable, preferably lowerable and/or raiseable. Preferably, the pyrolysis gas boiler comprises first elements and second elements, wherein the first elements are designed not to be vertically displaced upon vertical displacement of the drive shaft, and the second elements are designed to be vertically displaced upon vertical displacement of the drive shaft. In particular, it is provided that the first elements comprise at least one element from the group consisting of air supply means, displacement body, constriction ring, and ring, and/or the second elements comprise at least one element from the group consisting of a rotatable filter ring, surrounding central bell, and annular cage. This allows the reaction conditions to be controlled depending on the fuel type and fuel particle size. More precisely, the distances between specific elements in the pyrolysis gas boiler can be specifically adjusted. This allows both the comminution and mixing of the fuel as well as the filter function and thus the material flow to be significantly influenced and thus made controllable automatically.

In an advantageous further development, the vertical drive shaft is automatically vertically displaceable. This allows the operating states in the combustion chamber to be influenced automatically depending on specific operating conditions.

An electric motor, hydraulic or pneumatic drive is preferably provided for automatic relocation.

In an advantageous development, the air supply means comprise at least two nozzles. This allows for a particularly homogeneous air supply. The nozzles are preferably arranged in two nozzle planes.

If the nozzles are arranged in at least two nozzle levels with different vertical heights in relation to the vertical longitudinal extension of the pyrolysis gas boiler, then Melting out of the filter can also be prevented because at least one nozzle has a sufficient distance from the filter.

If two nozzles are designed to be independently switchable, shut-off, and/or metered, the air supply can be adjusted to specific operating conditions for optimal gasification. Alternatively, the nozzles can also have a predefined, fixed preset.

In an advantageous development, a constriction protruding inward from the boiler casing is provided, with one or more displacement bodies preferably arranged between the constriction and the air supply means. This effectively reduces or prevents dead spaces in this area toward the boiler wall, preventing the dead space from becoming clogged with fuel. This leads to a reduction or prevention of tar formation and optimized material flow.

In an advantageous further development, the displacement bodies are designed as ring segments. This makes them particularly easy to install in the boiler room.

In an advantageous development, the displacement bodies are designed to be interconnectable, preferably fixable. This makes the pyrolysis gas boiler particularly stable and durable, while the displacement bodies are still removable for maintenance purposes.

In an advantageous development, at least one displacement body is provided with a sight glass. Preferably, a sight glass is arranged on an outer wall of the pyrolysis gas boiler. The sight glass can be aligned radially with the sight glass of the displacement body, allowing a view into the boiler interior through the sight glasses. Depending on the position of the sight glass, the oxidation zone or the reduction zone can be visually monitored directly during the process, simplifying process adjustment.

In an advantageous further development, an inspection opening for removing the displacement body(s) is provided on an outer wall of the pyrolysis gas boiler. This allows the displacement bodies to be installed or serviced without completely opening the boiler casing, thus greatly simplifying these processes and thus reducing costs, also because the pyrolysis gas boiler requires shorter downtimes.

In an advantageous further development, means are provided for conveying material from an ash chamber of the pyrolysis gas boiler back into the oxidation zone and/or into the fuel bed (e.g., wood bed) located above the oxidation zone, wherein the means are preferably designed as screw and/or bucket conveyors in a particularly gas-tight housing. This achieves several advantageous effects. Firstly, the ash that is completely or partially conveyed back into the oxidation zone or into the fuel bed (e.g., wood bed) above the oxidation zone promotes a homogenization of the ember bed there or the fuel bed above the oxidation zone because it acts as a "lubricator." Secondly, larger components contained in the ash are subjected to post-gasification or post-combustion. Furthermore, the ash is thermally treated again, which removes impurities such as tar and phthalates, thus making the ash cleaner overall.

In an advantageous further development, with regard to the pyrolysis gas supply, there are means for filtering the pyrolysis gas downstream of the oxidation zone, wherein the means for filtering the pyrolysis gas are preferably arranged above and/or laterally on the gasification pan, wherein the means for filtering the pyrolysis gas in particular have filter openings which have a width in the range of 1 mm to 4 mm in at least one dimension. This results in a post-filtering of the pyrolysis gas, whereby larger particles return to the ember bed and are re-gasified or re-combusted there. This makes the pyrolysis gas even cleaner, and filter dust subsequently extracted from the pyrolysis gas no longer contains high concentrations of contaminants such as tar and phthalates, which is why the filter dust preferably no longer needs to be treated as hazardous waste without further treatment.

In an advantageous development, the boiler housing is thermally insulated at least in some areas, preferably with a cavity filled, in particular, with mineral and/or rock wool. This further reduces tar formation because condensation on a colder boiler housing wall is prevented. This insulation advantageously extends at least over the fuel inlet area (e.g., wood inlet), the oxidation zone, and the pyrolysis zone, preferably over the entire height of the boiler housing and, in particular, also over the boiler floor.

In an advantageous further development, it is provided that at least one discharge means exists that is designed to divert fuel (e.g., wood) from the inner wall of the boiler housing in the direction of the central axis of rotation, at least in one region of the boiler housing. The diverting means is preferably arranged above the air supply means. The diverting means, in particular, has a surface that extends conically downwards and inwards. The diverting means is preferably designed as a sheet metal with a conical segment surface. This also prevents tar formation because the fuel is diverted away from the colder boiler housing walls toward the hot areas.

In an advantageous further development, for which independent protection is claimed regardless of whether means for at least partially comminuting fuel (e.g., wood) and/or fuel coal (e.g., charcoal) are present inside the pyrolysis gas boiler, it is provided that above the grate there is at least one vane whose longitudinal axis runs in a non-radial orientation with respect to the central axis of rotation of the pyrolysis gas boiler. This has the advantage that the vane above the grate can push the ember bed in a specific direction, namely inwards or outwards depending on the inclination. In addition, this creates a better angle of attack to the passage slots in the grate. Overall, this allows the ash to be better mixed and transported through the grate.

In particular, when two blades are tilted in opposite directions, the blade assembly is designed to be more rigid, which increases the durability of the pyrolysis gas boiler. Oppositely aligned in this context does not mean that the angles of inclination should be identical, but rather opposite; rather, it is achieved when one blade has a positive inclination and the other a negative inclination relative to the radial orientation.

In an advantageous further development, there are at least two, preferably at least four, and especially at least eight blades. This allows for particularly effective ash processing through the grate.

In an advantageous further development, it is provided that at least one wing is designed to be rotatable, wherein the longitudinal axis is preferably also the axis of rotation of the wing, and/or that at least one wing is designed to be non-rotatable.

In an advantageous further development, the blade is oriented relative to the central rotation axis of the pyrolysis gas boiler at an angle of 5° to 25° or -5° to -25°, preferably 10° to 20° or -10° to -20°, in particular 15° or -15°, deviating from a radial orientation. These inclinations have proven particularly effective for working ash through the grate.

In an advantageous development, the blade is inclined relative to a horizontal plane, with the inclination preferably being in the range of 5° to 25° or -5° to -25°, preferably in the range of 10° to 20° or -10° to -20°, and in particular being 15° or -15°. The inclination preferably runs downwards from the inside to the outside. This inclination relative to the horizontal further promotes the displacement of the ash in a specific direction.

In conjunction with the horizontal inclination, the blade can be designed with an outer contour running parallel to the horizontal. This ensures particularly good mixing while simultaneously transporting the ash in the direction of the blade's longitudinal axis.

Independent protection is claimed for the method according to the invention for generating pyrolysis gas in a pyrolysis gas boiler with a boiler housing and a grate by the pyrolysis of wood or other suitable fuels in a bed of embers above the grate, wherein inside the pyrolysis gas boiler there are means for supplying air and means (99) for discharging the generated pyrolysis gas from the pyrolysis gas boiler, wherein in the boiler housing there is a central axis of rotation for one or more elements of the pyrolysis gas boiler, wherein the central axis of rotation is arranged parallel to the vertical longitudinal extent of the pyrolysis gas boiler, which is characterized in that at least partial comminution of fuel and/or fuel coal is carried out inside the pyrolysis gas boiler.

In an advantageous further development, it is provided that the pyrolysis gas boiler according to the invention is used within the scope of the process.

The claims filed now with the application and those filed later are without prejudice to the attainment of further protection.

Should a closer examination, particularly of the relevant prior art, reveal that one or another feature is beneficial to the purpose of the invention but not crucially important, then, of course, a formulation is already being sought that no longer contains such a feature, especially in the main claim. Such a subcombination is thus also covered by the disclosure of this application.

The references cited in the dependent claims indicate the further development of the subject matter of the main claim through the features of the respective subclaim. However, these are not to be understood as a waiver of independent, objective protection for the features of the referenced subclaims.

It should also be noted that the embodiments and variants of the invention described in the various embodiments and shown in the figures can be combined with one another as desired. Individual or multiple features are interchangeable. These feature combinations are also disclosed.

Features that were only disclosed in the description or individual features from claims that comprise a plurality of features can at any time be incorporated into the independent claim(s) as being of essential importance to the invention in order to distinguish them from the prior art, even if such features were mentioned in connection with other features or achieve particularly favorable results in connection with other features.

Thus, all features presented in the general description of the invention, the description of the embodiments, the claims, and the figures can be essential to the invention both individually and in any combination. These features or combinations of features can each form the basis of an independent invention, the right to claim which is expressly reserved. Individual features from the description of an embodiment do not necessarily have to be combined with one or more or all of the other features stated in the description of this embodiment; in this respect, each sub-combination is expressly disclosed. Furthermore, physical features of a device can be reformulated and used as method features, and method features can be reformulated and used as physical features of a device. Such a reformulation is therefore automatically disclosed.

• 1 der erfindungsgemäße Holzgaskessel in einer Seitenansicht,
• 2 der Holzgaskessel nach 1 in einer vertikalen Schnittansicht,
• 3 der Holzgaskessel nach 1 in perspektivischer Schnittansicht,
• 4 der Holgaskessel nach 1 in einer ersten Detailansicht im Schnitt,
• 5 der Holgaskessel nach 1 in einer zweiten Detailansicht im Schnitt,
• 6 die Rostbaugruppe des Holgaskessels nach 1 in einer Seitenansicht,
• 7 die Rostbaugruppe nach 6 in einer perspektivischen Ansicht,
• 8 die Rostbaugruppe nach 6 in einer Draufsicht von oben,
• 9 die Rostbaugruppe nach 6 in einer Draufsicht von unten,
• 10 eine erste Detailansicht der Rostbaugruppe nach 6 in einer perspektivischen Ansicht,
• 11 eine zweite Detailansicht der Rostbaugruppe nach 6 in einer Draufsicht von oben,
• 12 eine dritte Detailansicht der Rostbaugruppe nach 6 in einer Draufsicht von unten,
• 13 eine vierte Detailansicht der Rostbaugruppe nach 6 in einer perspektivischen Ansicht,
• 14 eine perspektivische Schnittansicht des Holzgaskessels nach 1 für einen ersten Betriebszustand und
• 15 eine perspektivische Schnittansicht des Holzgaskessels nach 1 für einen zweiten Betriebszustand.

The features and further advantages of the present invention will become clear below from the description of a preferred embodiment in conjunction with the figures. These show, purely schematically:

• 1 the wood gas boiler according to the invention in a side view,
• 2 the wood gas boiler after 1 in a vertical sectional view,
• 3 the wood gas boiler after 1 in perspective sectional view,
• 4 the wood gas boiler after 1 in a first detailed view in section,
• 5 the wood gas boiler after 1 in a second detailed view in section,
• 6 the grate assembly of the wood gas boiler 1 in a side view,
• 7 the grate assembly after 6 in a perspective view,
• 8 the grate assembly after 6 in a top view,
• 9 the grate assembly after 6 in a top view from below,
• 10 a first detailed view of the grate assembly after 6 in a perspective view,
• 11 a second detailed view of the grate assembly after 6 in a top view,
• 12 a third detailed view of the grate assembly after 6 in a top view from below,
• 13 a fourth detailed view of the grate assembly after 6 in a perspective view,
• 14 a perspective sectional view of the wood gas boiler according to 1 for an initial operating state and
• 15 a perspective sectional view of the wood gas boiler according to 1 for a second operating state.

In the 1 to 14 A preferred embodiment of the pyrolysis gas boiler according to the invention in the form of a wood gas boiler 10 is shown in various views.

It can be seen that the wood gas boiler 10 has an outer wall 12 with a lid 14 with an approximately octagonal outer geometry. Height-adjustable feet 18 are provided to space it from a support surface 16. A filling opening 20 for feeding the wood gas boiler 10 with wood (not shown) is provided in the lid 14.

Inside the wood gas boiler, spaced from the outer wall 12, is the boiler interior 22, which is essentially rotationally symmetrical about the longitudinal extension L and is surrounded by a boiler housing 24.

Viewed from top to bottom against the vertical direction V, the wood feeding chamber 26 is located below the filling opening 20, in which two rings 28 are arranged which taper conically downwards against the vertical direction V and act as deflection plates.

Below are the air supply means 30, which are fed from outside the wood gas boiler 10 (not shown), comprising two vertically spaced rings 32 of nozzles 34 that blow the supplied air into the oxidation zone 36. The air supply means 30 are optionally designed such that the nozzle rings 32 can be switched on and off and/or metered independently of one another with respect to the supplied air, as needed.

Below the oxidation zone 36 extends the reduction zone 38, which extends to the ash grate 40 of the wood gas boiler 10.

In the reduction zone 38 there is a constriction ring 42, which also has a deflection plate 44, which is designed as a conically tapering ring.

Below this deflector plate 44 there is another annular deflector plate 46 which widens conically towards the bottom.

Below this deflector plate 46 there is the ember bed 48 above the ash grate 40, which is worked through by wing rollers 50 of a wing arrangement 51 (cf. 13 ).

Above the constriction ring 42 there are again a plurality of ring-segment-shaped displacement bodies 52, which are firmly connected to one another via connections 54 (for example plug-in or screw connections).

These displacement bodies 52 have vertically extending ribs 56, which serve, among other things, to guide the material. There is also a horizontally extending ring 58 with protruding tongues 60.

Radially inwardly with respect to these tongues 60 there is a rotatable filter ring 62, the dimensions being adjusted so that an irregular gap 64 with a maximum width of 15 mm is formed between the tongues 60 and the filter ring 62.

The filter ring 62 itself has two different types of openings 66, 68. These generally extend inwardly in a curved manner, with the first type of opening 66 being bent inward clockwise and the other type of opening 68 being bent inward counterclockwise.

What both types of apertures 66, 68 have in common is that they narrow inward, preferably continuously, with the largest width being 15 mm radially outward and the smallest width being at least approximately 4 mm radially inward. The exact width is selected depending on the type of fuel used and the size of the fuel chips.

Above the filter ring 62 there are star-shaped tongue-like projections 70 which act as agitating means with respect to the filter ring 62 and work material through the openings 66, 68.

The filter ring 62 is circumferentially bounded on the outside by an irregularly shaped enclosure 72, with vertically extending plates 74 located in corresponding recesses. These plates are arranged radially recessed relative to the enclosure 72 and project vertically upwards above the filter ring surface. This creates a toothing with respect to the tongues 60 and the ribs 56, through which material located between these elements is crushed.

The plates 74 are part of an annular cage 76, which comprises a radially inwardly tapered section 78 and a vertically oriented section 80 with perforated slots 82. The perforated slots 82 facilitate the passage of the wood gas into the lower part of the wood gas boiler 10, reduce the pressure loss for conveying the wood gas, and yet effectively retain the embers and charred fuel particles until they reach a suitable size for the process steps located below this level on the boiler side.

In the area of the constriction ring 42, there is another ring 84, which points inward toward the cage 76. This ring 84, in turn, has tongues 86, forming another irregular gap 88, which also serves to filter and crush material.

The area around the wing rollers 50 is surrounded laterally above the grate 40 by a first enclosure 90, which is designed as a filter with slots 92. Furthermore, the first enclosure 90 is covered at the top by a filter cover 94, which also has openings 96. This filter cover 94 does not extend all the way to the deflector plate 44, so that material from the oxidation zone 36 can reach the area of the grate 40.

Developed wood gas can escape through the first enclosure 90 and the filter cover 94 and is directed into the annular space 98, from where it is extracted through the extraction nozzle 99. This annular space 98 is bounded at the bottom by another filter 100. The filter cover 94, the first enclosure 90, and the filter 100 prevent the passage of solid components into the annular space 98 (see. 5 ). Such solid components are returned through the filter cover 94 into the carburetor pan formed by the grate 40 and the first casing 90, where they are subjected to afterburning.

The wood gas boiler 10 has a drive unit (not shown in detail) that drives the vertical drive shaft 102. The casing 90, the filter ring 62, and the blade assembly 51 are in turn driven in the direction of rotation _DR by a further drive (not shown) acting tangentially on the boiler internals (see 13 ), which thereby move continuously or in a back and forth movement relative to the fixed components of the wood gas boiler 10, in particular the stirring ring 42, the ash grate 40 and the stirring means 70, and thus guide the material through the wood gas boiler 10.

The wing rollers 50 are thereby rotated on the one hand above the grate 40 and on the other hand these wing rollers 50 rotate about their horizontal axis in the direction of rotation D _F (cf. 13 ), whereby the drive gears 104 are rotated indirectly by the bolts 105.

The main axis 102 is fixedly connected to a central bell 106, which can also rotate during operation of the wood gas boiler 10, whereby this bell guides the material radially outwards and in the direction of the gap 64 and at the same time loosens the slipping fuel materials and releases any caking of the material.

Furthermore, the following elements of the wood gas boiler 10 are used:

There is a conveying device (not shown), which is preferably designed as a screw and/or bucket conveyor in a particularly gas-tight housing, and which transfers material from an ash chamber 108 of the wood gas boiler 10, preferably via the ash discharge opening 110 via a return opening 112, into the oxidation zone 36 and/or into the wood bed 26 located above the oxidation zone 36. The returned ash evens out the ember bed in the oxidation zone 36 or the wood bed 26 above the oxidation zone 36 because it acts as a "lubricator." Secondly, larger components contained in the ash are subjected to post-gasification or post-combustion. In addition, the ash is thermally treated again, whereby impurities such as tar and phthalates are removed and the ash is thus cleaner overall.

At least one displacement body 52 is provided with a sight glass 114, which corresponds to the sight glasses 116 in the covers of an inspection hatch 117a on the outer wall 12 of the wood gas boiler 10, allowing the interior to be viewed and the processes inside the wood gas boiler 10 to be monitored. In addition, there are preferably two inspection openings 117a, 117b through which the displacement bodies 52 can be removed and serviced if necessary.

Between the outer wall 12 of the wood gas boiler 10 and the boiler casing 24 there is thermal insulation (not shown) with mineral and/or rock wool in corresponding cavities.

On the underside of the wood gas boiler 10 there is a supply line 118 for the optional supply of, for example, water vapor or other process-influencing substances, including the option for the return of treated or untreated wood gas, among other things, for influencing the temperature of the reactions and the components of the interior of the wood gas boiler 10 in the vicinity of the central drive axis L of the wood gas boiler 10 (cf. 1 ).

There is an auxiliary inspection opening 120 through which the drive can be cleaned of ash.

In the 6 to 13 the grate assembly 122 of the wood gas boiler 10 according to the invention is shown in more detail.

It can be seen that the grate assembly 122 includes the grate 40, which has non-radially aligned slots 124 extending spirally around the central axis of rotation (see FIG. 9 ).

The grate 40 is laterally surrounded by a second frame 126, which guides the remaining fuel and ash away from the boiler wall 24 closer to the boiler center L.

Especially in the 11 , 12 and 13 It can be seen that the wing arrangement 51 comprises, on the one hand, the wing rollers 50 and, on the other hand, horizontal wings 128, which have a vertical section 130 which serves for the lateral mounting of the respective associated wing roller 50 with its drive gear 104.

The wing rollers 50 and the horizontal wings 128 are each arranged on adjacent sides 132, 134 of a star element 136, wherein the normals of one side 132 or the wing rollers 50 have an inclination of -10° with respect to the radial R of the central axis of rotation L and wherein the normals of the other side 134 or the horizontal wings 128 have an inclination of +15° with respect to the radial R of the central axis of rotation L (cf. 12 ). In addition, the wing rollers 50 can also have an inclination relative to the horizontal H.

Due to this special design of the wing assembly 51, in which the wing roller 50 forms an angle of 25° with the associated horizontal wing 128, the wing assembly 51 is particularly rigid and durable. Furthermore, the ember bed above the grate 40 is particularly well worked by the horizontal wing 128 due to the rotation D _F of the wing rollers 50 around their longitudinal axis L and the simultaneous rotation D _R of the wing assembly 51 around the longitudinal axis L, and the wing rollers work the ash particularly well through the slots 124 of the grate 40.

The wall 138 represents an additional funnel of the filter cover 94, into which the deflector plate 44 projects and which in turn is intended to ensure that the fuel reaches the center of the grate assembly 122 and is not distributed in the rest of the wood gas boiler 10 by the suction of the gas flow.

The windows 140 in the frame 90 are inspection hatches and serve to empty the filter basket 90 (the boiler's gasification pan) in the event of a malfunction. The filter basket 90 can be emptied through these inspection hatches 140 even when hot, e.g., if the drive cannot function optimally or is blocked due to the unintentional introduction of interfering material such as metal parts or stones. The corresponding inspection opening in the outer shell 12 of the wood gas boiler 10 is not shown and is located in the cut-out part of the views. 2 and 3 .

Finally, from the 14 and 15 It can be seen that a pneumatic drive unit 142 is located on the underside of the wood gas boiler 10, which is fed via an air duct (not shown). This pneumatic drive unit 142 serves to vertically raise and lower the central drive shaft 102.

For this purpose, the pneumatic drive unit 142 has four cylinders 144, 146, 148, 150 arranged in pairs opposite each other from the central rotational axis L, each providing a stroke of 5 mm, 10 mm, 20 mm, and 30 mm, respectively. These strokes can be applied individually or in combination, resulting in total strokes for the vertical drive shaft 102 ranging from a minimum of 5 mm to a maximum of 65 mm.

Cylinders 144, 146, 148, and 150 each act on associated planes 152, 154, 156, and 158, respectively. Cylinders 144, 146, 148, and 150 not assigned to a plane 152, 154, 156, and 158 do not act on these planes. The final plane 158 carries the vertical drive shaft 102.

The entire pneumatic drive unit 142 is firmly connected to the pyrolysis gas boiler 10 via the brackets 160.

While the elements rotatable filter ring 62, enclosure 72, central bell 106 and annular cage 76 are attached to the vertical drive shaft 102 and can thus be displaced vertically, the elements means 30, 34 for air supply, displacement body 52, constriction ring 42 and ring 84 are not arranged on the vertical drive shaft 102, they therefore remain vertically undisplaced when the vertical drive shaft 102 is displaced.

In 14 the state of the pyrolysis gas boiler 10 is shown in which the vertical drive shaft 102 is completely lowered, and in 15 the state of the pyrolysis gas boiler 10 is shown in which the vertical drive shaft 102 is completely raised.

The raising and lowering of the vertical drive shaft 102 can be done manually or automatically. For automated raising, conditions such as the negative pressure at various boiler positions, the wood gas or component temperature determined by thermal sensors, the fuel mass flow, the air volume, and, for example, the change in flow resistance in the downstream gas cleaning system and/or the pyrolysis gas composition can be monitored, and the pneumatic drive unit 142 can be controlled accordingly via a control unit (not shown). Instead of the pneumatic drive unit 142, an electric motor or hydraulic drive can also be provided.

By controlled raising or lowering of the central, vertical drive shaft 102 during operation of the wood boiler 10, the operating conditions in the combustion chamber can be significantly influenced, since the central, vertical drive shaft 102 simultaneously raises the independently rotatable and driven filter ring 62 and the so-called central bell 106 driven by the shaft 102. This process-influencing measure of raising or lowering the components changes the distance of the filter ring 62 to the air supply 32 and varies simultaneously, the cross-section of the gap 64 between the filter ring 62 and the tongues 60 of the enclosure 72. Both measures influence the pyrolysis process, firstly, by influencing the combustion chamber size (reduction when raised, increase when lowered) and, secondly, by influencing the material flow from the pyrolysis area into the filter basket 90 (increase when raised and decrease when lowered). This allows the reaction conditions to be controlled depending on the fuel type and fuel particle size. More precisely, this function can significantly influence both the comminution and mixing of the fuel as well as the filter function and thus the material flow, making it possible to control it automatically.

From the above, it has become clear that the present invention provides a solution that brings effective improvements. More specifically, the inventive solution eliminates at least some of the problems of known wood gas boilers. Above all, the inventive wood gas boiler 10 is technically not very complex and thus less susceptible to damage. Very little tar and other undesirable reaction products are produced, and in particular, the wood gas produced is very pure.

List of reference symbols

10

preferred embodiment of the pyrolysis gas boiler according to the invention

12

exterior wall

14

Lid

16

Installation area

18

height-adjustable feet

20

Filling opening

22

Boiler interior

24

boiler housing

26

Fuel loading room

28

rings tapering downwards in a vertical direction, deflector plates

30

Air supply

32

Rings of nozzles 34

34

nozzles

36

Oxidation zone

38

Reduction zone

40

Ash grate

42

Constriction ring

44

deflector plate

46

deflector plate

48

Ember bed

50

wing rollers

51

Wing arrangement

52

Displacement body

54

Screw connections

56

ribs

58

ring

60

tongues

62

rotating filter ring

64

irregular gap between tongues 60 and filter ring 62

66, 68

Breakthroughs

70

tongue-like projections

72

Enclosure

74

vertically running panels

76

ring-shaped cage

78

radially inwardly tapered section

80

vertically aligned section

82

Breakthrough slots

84

ring

86

tongues

88

irregular gap

90

first frame, filter basket

92

slots

94

filter cover

96

Breakthroughs

98

Annular space

99

Suction nozzle

100

filter

102

vertical drive shaft

104

Drive gears

105

bolt

106

central bell

108

Ash room

110

Ash discharge opening

112

Return opening

114

sight glass

116

sight glasses

117a, 117a

Inspection hatches

118

Supply line for steam

120

Auxiliary inspection opening

122

Grate assembly

124

non-radially aligned slots

126

second border

128

Horizontal wing

130

Vertical section

132, 134

adjacent pages

136

Star element

138

Wall, funnel

140

Windows, inspection hatches

142

pneumatic drive unit

144, 146

cylinder

148, 150

cylinder

152, 154

Levels

156, 158

Levels

160

Brackets of the pneumatic drive unit 142 on the pyrolysis gas boiler 10

DF

Rotation of the wing rollers 50

DR

Rotation of the wing assembly 51

H

horizontal

L

central axis of rotation, longitudinal extension of the pyrolysis gas boiler 10

R

Radial

V

vertical

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10 2009 042 104 A1 [0002]
• DE 10 2021 002 475 A1 [0002]
• DE 10 2021 002 478 A1 [0002]
• DE 10 2021 002 657 A1 [0002]
• DE 10 2021 002 658 A1 [0002]
• DE 20 2021 001 720 U1 [0002]

Claims (15)

Pyrolysis gas boiler (10) with a boiler housing (24) and a grate (40) for generating pyrolysis gas by the pyrolysis of wood or other suitable fuels in a bed of embers (48) above the grate (40), wherein in the interior (22) of the pyrolysis gas boiler (10) there are means (30, 34) for supplying air and means (99) for discharging the generated pyrolysis gas from the pyrolysis gas boiler (10), wherein in the boiler housing (24) there is a central axis of rotation (L) for one or more elements of the pyrolysis gas boiler (10), wherein the central axis of rotation (L) is arranged parallel to the vertical longitudinal extent (V) of the pyrolysis gas boiler (10), characterized in that in the interior (22) of the pyrolysis gas boiler (10) there are means (56, 58, 60, 62, 64, 66, 68, 70, 86, 88) for at least partial comminution of fuel and/or fuel coal. Pyrolysis gas boiler (10) according to Claim 1 , characterized in that a filter (62) with an upwardly directed filter surface is provided in the interior of the pyrolysis gas boiler (10), wherein the filter (62) is surrounded by a frame (68, 60) located on the boiler housing (24), wherein an intermediate space (64) exists between the filter (62) and the frame (58, 60), wherein the filter (62) is preferably a further grate, wherein it is provided in particular that elevations (70, 74) exist on the filter surface, which elevations are preferably arranged on the filter (62) radially outwardly in the vicinity of the circumference of the filter (62), and/or that at least one stirring means (70) is arranged above the filter surface so as to be movable with respect to the filter surface, wherein the stirring means (70) is preferably designed in a star shape with respect to the central axis of rotation (L), and/or that on the filter (62) and/or the frame (58, 60) of the filter (62) with respect projections (60, 64) extending radially on the central axis of rotation (L) are arranged, wherein such projections (60, 64) preferably exist over the entire vertical height of the filter (62) and/or the frame (58, 60), and/or that the filter (62) is designed to be rotatable relative to the frame (58, 60). Pyrolysis gas boiler (10) according to Claim 2 , characterized in that slots (66, 68) are arranged in the filter surface, wherein the slots (66, 68) preferably: - have at least two different widths over their radial extent, in particular are wider radially on the outside than radially on the inside, and/or - run radially inclined, in particular are arcuate, and/or - are aligned identically in groups, wherein in particular there are at least two groups (66, 68) which are arranged adjacent to one another, wherein the slots (66, 68) of one group (66, 68) are aligned differently than the slots (68, 66) of the other group (68, 66), wherein preferably the slots (68) of one group (68) run radially inclined outwards in a clockwise direction and the slots (66) of the other group (66) run radially inclined outwards in a counterclockwise direction. Pyrolysis gas boiler (10) according to one of the Claims 1 until 3 , characterized in that the central axis of rotation (L) comprises a vertical drive shaft (102) which is designed to be vertically displaceable, preferably lowerable and/or raiseable, wherein in the pyrolysis gas boiler (10) there are preferably first elements (30, 34, 52, 72, 84) and second elements (62, 76, 106), wherein the first elements (30, 34, 52, 72, 84) are designed not to be displaced vertically upon a vertical displacement of the drive shaft (102), and the second elements (62, 76, 106) are designed to be displaced vertically upon a vertical displacement of the drive shaft (102), wherein it is provided in particular that the first elements comprise at least one element from the group: means (30, 34) for air supply, displacement body (52), constriction ring (42) and ring (84) and/or the second elements comprise at least one element from the group: rotatable filter ring (62), enclosure (72), central bell (106) and annular cage (76). Pyrolysis gas boiler (10) according to one of the preceding claims, characterized in that the means for supplying air have at least two nozzles (34), which are preferably - arranged in at least two nozzle planes (32), which are arranged at different vertical heights in particular with respect to the vertical longitudinal extent (V) of the pyrolysis gas boiler (10) and/or - are designed to be switchable and blockable and/or meterable independently of one another. Pyrolysis gas boiler (10) according to one of the preceding claims, characterized in that there is a constriction (42) projecting inwards from the boiler housing (24), wherein one or more displacement bodies (52) are preferably arranged between the constriction (42) and the means (30, 34) for supplying air. Pyrolysis gas boiler (10) according to Claim 6 , characterized in that the displacement bodies (52) are designed as ring segments and/or that the displacement bodies (52) are designed to be interconnectable, preferably fixable, and/or that at least one displacement body (52) is provided with a sight glass (114), wherein a sight glass (116) is preferably arranged on an outer wall of the pyrolysis gas boiler (10), which sight glass can be aligned in radial alignment with the sight glass (114) of the displacement body (52) so that the boiler interior (22) can be seen through the sight glasses (114, 116), and/or that an inspection opening (117a, 117b) for removing the displacement body(s) (52) is provided on an outer wall of the pyrolysis gas boiler (10), wherein a sight glass (116) is preferably arranged at the inspection opening (117a). Pyrolysis gas boiler (10) according to one of the preceding claims, characterized in that means for conveying material from an ash chamber (108) of the pyrolysis gas boiler (10) back into the oxidation zone (36) and/or into the fuel bed (26) located above the oxidation zone (36) exist, wherein the means are preferably designed as screw and/or bucket conveyors in a particularly gas-tight housing. Pyrolysis gas boiler (10) according to one of the preceding claims, characterized in that with regard to the pyrolysis gas guide downstream of the oxidation zone (36) there are means (62) for filtering the pyrolysis gas, wherein the means (62) for filtering the pyrolysis gas are preferably arranged above and/or laterally on the gasifier pan, wherein the means (62) for filtering the pyrolysis gas have in particular filter openings (66, 68) which have a width in the range of 1 mm to 20 mm, preferably of 4 mm to 15 mm, in at least one dimension. Pyrolysis gas boiler (10) according to one of the preceding claims, characterized in that the boiler housing (24) is designed to be thermally insulated at least in some regions, wherein there is preferably a cavity which is filled in particular with mineral and/or rock wool, and/orthat there is at least one discharge means (28) which is designed to discharge fuel from the inner wall (24) of the boiler housing (24) in the direction of the central axis of rotation (L) at least in one region of the boiler housing (24), wherein the discharge means (28) is preferably arranged above the means (30, 34) for supplying air, wherein the discharge means (28) in particular has a surface which runs conically downwards and inwards, wherein the discharge means (28) is preferably designed as a sheet metal piece with a conical shell segment. Pyrolysis gas boiler (10) according to one of the preceding claims, characterized in that above the grate (40) there is at least one wing (50, 128) whose longitudinal axis runs in a non-radial orientation with respect to the central axis of rotation (L) of the pyrolysis gas boiler (10). Pyrolysis gas boiler (10) according to Claim 11 , characterized in that there are at least two, preferably at least four, in particular at least eight vanes (50, 128) and/or that at least one vane (50) is designed to be rotatable, wherein the longitudinal axis is preferably also the axis of rotation of the vane, and/or that at least one vane (128) is designed to be non-rotatable, and/or that there are at least two vanes (50, 128) which have an oppositely directed inclination, and/or that the orientation of the vane (50, 128) with respect to the central axis of rotation (L) of the pyrolysis gas boiler (10) is in an orientation of 5° to 25° or -5° to -25°, preferably of 10° to 20° or -10° to -20°, in particular of 15° or -15° deviating from a radial orientation Pyrolysis gas boiler (10) according to Claim 11 or 12 , characterized in that the wing (50) is inclined with respect to a horizontal plane, - wherein the inclination is preferably in the range 5° to 25° or -5° to -25°, preferably in the range of 10° to 20° or -10° to -20° and in particular 15° or -15°, and/or - wherein the inclination is preferably inclined downwards from the inside to the outside, and/or - wherein the wing (50) has an outer contour running parallel to the horizontal (H). Method for generating pyrolysis gas in a pyrolysis gas boiler (10) with a boiler housing (24) and a grate (40) by the pyrolysis of wood or other suitable fuels in a bed of embers (48) above the grate (40), wherein in the interior (22) of the pyrolysis gas boiler (10) there are means (30, 34) for supplying air and means (99) for discharging the generated pyrolysis gas from the pyrolysis gas boiler (10), wherein in the boiler housing (24) there is a central axis of rotation (L) for one or more elements of the pyrolysis gas boiler (10), wherein the central axis of rotation (L) is arranged parallel to the vertical longitudinal extent (V) of the pyrolysis gas boiler (10), characterized in that an at least partial comminution of fuel and/or fuel coal is carried out in the interior (22) of the pyrolysis gas boiler (10). Procedure according to Claim 14 , characterized in that the pyrolysis gas boiler (10) according to one of the Claims 1 until 13 is used.