Device and method for thermochemically producing syngas from carbon-containing synthetic substances and / or biomass

Abstract

The invention is used to thermochemically produce syngas using a fixed-bed shaft reactor (1) that is operated in a co-current mode and has a reaction chamber through which carbon-containing synthetic substances (2) and / or solid biomass particles (3) flow from top to bottom. By continuously adding an oxygen-containing gas (7) in an autothermal gassing process, a raw syngas is produced in the shaft reactor (1) as the gas flows through a fuel pre-heating zone (4), a pyrolysis zone (5), and an oxidation zone (6) arranged downstream thereof, and the syngas is drawn at the lower end of the fixed-bed shaft reactor (9) together with fly ash after additionally flowing through a reduction zone (8). After exiting the reduction zone (8), the raw syngas flows through an entrained-flow zone (12) which is located below the reduction zone (8) in the reactor. In order to improve the efficiency by using the sensible excess heat of the produced syngas, the invention proposes providing an inlet for the oxygen-containing gas (7) below the reduction zone (8), and the walling of the reactor in the entrained-flow zone (12) is designed to be double-walled at least in some regions in the form of a heat exchanger with at least one heat exchanger surface (18), wherein the oxygen-containing gas is conducted through a gas pre-heating zone (17) formed in the heat exchanger such that the outflowing raw syngas is cooled, and the oxygen-containing gas is heated.

Description

[0001] Apparatus and method for the thermochemical production of synthesis gas from carbon-containing synthetic substances and / or biomass

[0002] The invention relates, according to the preamble of claim 1, to a device and a method for the thermochemical production of synthesis gas with a fixed-bed shaft reactor operated in cocurrent, the reaction chamber of which is flowed through from top to bottom with carbon-containing synthetic substances and / or with solid biomass particles and in which a raw synthesis gas is generated by passing through a fuel preheating zone, pyrolysis zone and a downstream oxidation zone by continuously metering in oxygen-containing gas in an autothermal gasification process, and after further flowing through a reduction zone at the lower end of the fixed-bed shaft reactor is withdrawn together with fly ash, wherein the raw synthesis gas, after leaving the reduction zone, flows through an entrained flow zone which is located below the reduction zone in the reactor,

[0003] A device of the type mentioned above is known from EP 2 752 478 A1.

[0004] Further devices of this type are known from DE 102 24 531 B4, DE 10 2009 020 033 B4, DE 10 2012 009 200 A1 and DE 10 2014 016856 A1.

[0005] DE 31 31 476 C2 describes a wood gasifier in which the reactor section of the device is double-walled. The air supply is located in the head area of ​​the gasifier to promote targeted condensate formation and separation, which can be problematic when using moist wood.

[0006] WO 2011 / 101022 A1 discloses a gasification device in which the air is introduced directly at the level of a gasification zone without passing through a heat exchanger. The oxidation zone is located radially within the gasification zone, and the air is supplied to the oxidation zone via an inlet at the head of the gasification device.

[0007] The object of the present invention is to improve a device of the type mentioned at the outset with regard to its efficiency.

[0008] According to the invention, the object is achieved by a device in which an inlet for the oxygen-containing gas is provided below the reduction zone and the wall of the reactor in the entrained flow zone in the reactor is at least partially double-walled as a heat exchanger with at least one heat transfer surface, wherein the oxygen-containing gas is passed through a gas preheating zone formed in the heat exchanger, so that the outflowing raw synthesis gas is cooled in the entrained flow zone and the oxygen-containing gas is heated.

[0009] The inventive solution offers the advantage that a significant portion of the heat contained in the generated synthesis gas can be better utilized and returned to the process via the heat exchanger, thus improving efficiency and requiring less oxygen-containing gas relative to the fuels supplied. The cold gas efficiency is optimized, resulting in a reduction in CO2 emissions.

[0010] Due to the increase in volume that occurs with the increase in temperature, the flow velocity when entering the reactor also increases while the flow cross-section remains the same, so that a better penetration of the bed can be achieved.

[0011] In a preferred embodiment of the invention, a gas duct for the oxygen-containing gas is provided between the heat exchanger in the entrained flow zone and the oxidation zone. This means that the supplied oxygen-containing gas is first passed through the heat exchanger in the entrained flow zone at the base of the device, where it cools the synthesis gas produced during the process and is itself heated in the process. It is then passed into a higher-lying region of the device and fed to the oxidation zone. From there, it then passes through the process in cocurrent with the carbon-containing synthetic substances and / or solid biomass particles to the entrained flow zone, forming synthesis gas.

[0012] A particularly preferred embodiment of the invention provides that the outer wall and / or the bottom of the entrained flow zone are at least partially double-walled as a heat exchanger with heat transfer surfaces.

[0013] The double-walled design can be integrated particularly well into the reactor and at the same time provides thermal insulation of the reactor from the environment.

[0014] A particularly preferred development of the invention is one in which the heat transfer surfaces are formed with ribs and / or projections with internal flow channels for the oxygen-containing gas to enlarge the effective surfaces.

[0015] This structurally somewhat more complex measure increases the effective surfaces for heat exchange between the gas media.

[0016] A particularly preferred embodiment of the invention provides that the reactor shaft is designed as an annular shaft reactor by means of an inner cylinder, wherein the inner cylinder is located in the center of the oxidation zone, the reduction zone and the entrained flow zone.

[0017] The design as an annular shaft reactor over the key process zones offers better control of the process sequence with a lower risk of undesirable vertical displacement of the zones (e.g., core flow in the bed center). Furthermore, fixed-bed shaft reactors often have the problem that the bed center cannot be sufficiently homogeneously supplied with oxygen-containing gas. The inner cylinder solves this problem by filling the bed center with its body, whereby the bed center is no longer present in the crucial reactor zones. A preferred geometry of the annular shaft of the annular shaft reactor provides that the quotient formed from the inner diameter of the oxidation zone and the outer diameter of the inner cylinder is less than 20, preferably less than 15, and particularly preferably less than 10.

[0018] A further preferred embodiment provides for the inner cylinder to have a rotary drive and radially projecting attachments to enable mechanical movement of the fixed bed through the rotational movement of the inner cylinder during the gasification process. This measure achieves homogenization of the fixed bed and reduces the risk of bridging and hollow fires, which can lead to hot spots and slagging. Furthermore, gas preferential channels are prevented, thus ensuring a very homogeneous gas flow through the fixed bed.

[0019] A constructive implementation of the principle can, for example, provide that the vertical inner cylinder is equipped as a hollow shaft and, in the area of ​​the oxidation zone, is equipped with several hollow stirring fingers projecting into the fixed bed and provided with nozzle holes as attachments and is firmly connected, through which the oxygen-containing gas is passed and dosed into the oxidation zone via the nozzle holes of the stirring fingers.

[0020] A preferred embodiment of the invention provides that the vertical inner cylinder is surrounded by a dome in the area of ​​the entrained air flow zone. The dome can protect the inner cylinder from excessive thermal stress caused by the hot gases in the entrained air flow zone, but can also perform a number of other functions.

[0021] For example, in a preferred embodiment of the invention, a pivot bearing for the inner cylinder can be arranged at the end of the mandrel facing the agitator fingers. This bearing point, positioned closer to the agitator fingers, offers the advantage that moments acting on the inner cylinder can be better absorbed, since the leverage on the bearing surfaces is reduced at this bearing point.

[0022] Furthermore, it can preferably be provided that the dome is formed as part of the heat exchanger and is flowed through by the oxygen-containing gas, wherein its peripheral surface forms a heat transfer surface. This improves the efficiency of the heat exchanger overall. A further, particularly preferred embodiment of the invention provides that the rotating inner cylinder has openings in its walls through which the oxygen-containing gas, after flowing through the heat exchanger, is introduced into the rotating inner cylinder via moving openings in the wall of the latter. Various guides are possible for the gas flow. In a first embodiment, these openings are located, for example, below the bottom of the reactor below the point at which the inner cylinder passes through the bottom, but they can also be located in the dome described above in order to ensure particularly good flow through the latter.

[0023] To further prevent the entry of oxygen-containing gas into the entrained flow zone, an axial mechanical seal is provided in the area of ​​a rotary union at the head of the dome. This seal comprises a rotating sealing body rigidly connected to the inner cylinder and a static sealing body rigidly connected to the dome. The two sealing bodies are pressed axially against each other via sealing surfaces, for example, by a spring element, thus ensuring a particularly good gas seal.

[0024] It is particularly preferred that the openings in the inner cylinder open into a chamber separated from a gas preheating zone located at the bottom of the entrained-flow zone by an intermediate floor with a passage opening. The additional intermediate floor, which is located upstream of this chamber in the direction of flow, increases the average residence time of the oxygen-containing gas in the area of ​​the heat transfer surfaces and thus increases the efficiency of the heat exchanger.

[0025] Another measure in the area of ​​the passage point could involve a dome extending into the entrained flow zone, enclosing the inner cylinder at this point. The dome can serve several functions. First, it can serve as a bearing point for the inner cylinder. This bearing point is located closer to the end of the inner cylinder that extends into the reactor, thus improving the bearing through more favorable axial positioning.

[0026] The dome can also provide thermal protection for the inner cylinder and, if necessary, be provided with a heat exchanger channel through which the supplied oxygen-containing gas is passed.

[0027] According to a further preferred embodiment of the invention, the height of the nozzle holes in the reactor of the oxidation zone and the reduction zone is adjustable. This allows the residence times in the individual reactor zones to be varied, which can be advantageous for process control.

[0028] Adjusting the altitude can enable this function even without the heat exchange elements according to the invention.

[0029] Changing the altitude offers considerably more flexible usability of the system and enables adaptation, for example, to different qualities of the material to be gasified. Such a change in altitude can be achieved through simple structural measures on the inner cylinder. For example, a modular inner cylinder is conceivable, the parts of which can be removed and fixed in different relative positions to one another. A threaded connection between the parts is also possible in order to be able to adjust the altitude continuously, if necessary even during operation, so that processes during the process can be reacted to for control purposes. Changing the altitude can, for example, affect the position of the nozzle stars, the ignition unit and possibly other functional elements. It is also possible to use different nozzle star geometries interchangeably or to change the geometry using adjustable elements.

[0030] A further embodiment, which is again advantageous independently of the features of the invention, provides that the reduction zone with the fixed bed contained therein is separated from the entrained-flow zone by a disc grate with defined gaps between the discs, which serves as a passage for the raw synthesis gas into the entrained-flow zone and as a barrier for coarse solid particles. Parts of the disc grate are permanently attached to the vertical inner cylinder as an attachment. The targeted removal of coarse particles from the fixed bed ensures a robust process sequence.

[0031] A further design measure that helps improve reactor operation even without the presence of the heat exchanger elements according to the invention provides for the carbon-containing synthetic substances and / or biomasses to be moved continuously or discontinuously in the fuel preheating zone with the aid of an agitator. The fill level of the carbon-containing synthetic substances and / or biomasses in the fuel preheating zone is detected by measuring the torque of the agitator, and the measured value is used as a control variable for regulating the flow rate of the carbon-containing synthetic substances. Preferably, the agitator fingers of the agitator are geometrically designed to increase the compaction of the material downward in the flow direction, thereby preventing hollow fires and gas preferential channels.The rotational movements of the inner cylinder and the agitator can be coordinated, whereby they can rotate in the same direction or in opposite directions.

[0032] In a possible embodiment of the invention, it is provided that the fixed-bed shaft reactor has a plurality of reaction chambers arranged parallel to one another, in each of which an inner cylinder is arranged.

[0033] This allows the device to be scaled for the respective application without redesigning all components and the throughput can be increased accordingly if there is a need for this.

[0034] An advantageous development of such a multiple gasifier provides for a number of disc grates corresponding to the number of reaction chambers, with a discharge opening arranged centrally between two or four disc grates. The discharge opening between the disc grates facilitates the removal of coarse, non-gasifiable solid particles. The discharge opening is preferably located centrally between each four disc grates.

[0035] The present invention also relates to a process for the thermochemical production of synthesis gas for implementation in a device of the type described above in a fixed-bed shaft reactor operated in cocurrent, the reaction chamber of which is flowed through from top to bottom with carbon-containing synthetic substances and / or with solid biomass particles and in which a raw synthesis gas is generated by passing through a fuel preheating zone, pyrolysis zone and a downstream oxidation zone by continuously metering in oxygen-containing gas in an autothermal gasification process, and after further flowing through a reduction zone at the lower end of the fixed-bed shaft reactor is withdrawn together with fly ash, wherein the raw synthesis gas, after leaving the reduction zone, flows through an entrained flow zone located below the reduction zone, characterized in thatthat the oxygen-containing gas is fed via an inlet below the reduction zone and is passed through a gas preheating zone in the region of the entrained flow zone in the reactor through a heat exchanger having at least one heat transfer surface, wherein the outflowing raw synthesis gas is cooled in the entrained flow zone and the oxygen-containing gas is heated.

[0036] The oxygen-containing gas is then led, for example, from the heat exchanger in the entrained flow zone into the oxidation zone, where it is introduced into the reactor.

[0037] A further development of the process may provide for the use of air and / or technical oxygen, or a mixture thereof, as the oxygen-containing gas. The composition can, in turn, depend on the substances to be gasified.

[0038] Furthermore, in a preferred embodiment of the process, it can be provided that water vapor and / or gaseous carbon dioxide (15) is added to the oxygen-containing gas. The addition of such substances can be useful for reasons of temperature control in order to protect the material from thermal overload in those areas that are exposed to particularly high process temperatures. The addition can also

[0039] Increase gas flow to enable better loosening of the fixed bed in the area of ​​injection of the oxygen-containing gas by the increased gas flow with possibly increased flow velocity.

[0040] It is also possible to cool the components of the reactor that are subject to particularly high thermal stress using a separate coolant that is not fed into the process and can, if necessary, be circulated via a separate heat exchanger for heat dissipation.

[0041] Regarding the introduction of steam into the process, it can be provided that the steam is generated by dosing water into the gas preheating zone through evaporation at the heat transfer medium surface and is then mixed directly with the oxygen-containing gas in the gas preheating zone. However, it is also easily possible to dosing it in the inner cylinder itself or even in the nozzles.

[0042] A particularly preferred embodiment of the invention provides for the addition of alkaline earth metal-containing substances, preferably calcium-containing substances, and particularly preferably calcium hydroxide and / or calcium oxide, to the carbon-containing synthetic substances and / or biomasses to bind acid gases, halogens, sulfur compounds, and heavy metals released in the fixed-bed shaft reactor (1). This measure has proven particularly advantageous when the process is intended to thermally utilize critical fractions, which contain, for example, plastics that are difficult to recycle and cannot be disposed of in landfills, or contaminated substances, and convert them into synthesis gas.

[0043] Further measures may concern the soil discharge from the reactor. For example, air injection into a screw conveyor for material discharge may be provided to promote the combustion of combustible particles still present in the ash and thus reduce the proportion of coal during discharge.

[0044] A gas valve in the syngas outlet stream can be advantageous, for example, if the syngas is to be used directly for thermal purposes in a CHP plant. The gas valve in the CHP supply line compensates for pressure waves that can be transmitted from the gasifier due to pressure fluctuations and could disrupt the CHP plant's operation.

[0045] Optionally, a recirculation of the synthesis gas for cooling purposes can also be provided, with which, for example, cooling can be achieved especially when the reactor is shut down in order to ensure thermal protection of the materials.

[0046] As safety features, the device may have a burn-back extinguishing device and / or liquid lock.

[0047] A further preferred embodiment of the invention relates to the rotary feedthrough from the agitator of the fuel preheating zone into the carburetor, which can be provided with a barrier gas seal.

[0048] The grate can have multiple discs. The number of discs depends on the diameter, although roughly speaking, the larger the diameter, the more discs are required.

[0049] Stirring fingers can be provided to prevent solids buildup in the entrained flow zone. The reactor can preferably be provided with a fireclay lining on the inside to protect the walls from thermal overload.

[0050] A further preferred development of the method can provide that the fill level of the carbon-containing synthetic substances and / or biomasses in the fuel preheating zone is detected and the supply of the carbon-containing synthetic substances and / or biomasses is automatically controlled via a conveying device.

[0051] A particularly preferred embodiment of the method provides that the pressure difference across the fixed bed in the fixed bed shaft reactor (1) is measured and that the measured value is used as a control variable for regulating the rotational movement of the vertical inner cylinder (10) and the attachments of the vertical inner cylinder (10).

[0052] Furthermore, it is possible that the throughput of carbon-containing synthetic substances (2) and / or biomasses (3) through the fixed-bed shaft reactor (1) is achieved by adjusting the volume flow of oxygen-containing gas (7).

[0053] With a static, non-rotating inner cylinder, the carburetor can also be operated and scaled with only externally mounted jets.

[0054] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the exemplary embodiments described below with reference to the drawings. They show:

[0055] Fig. 1 shows a schematic longitudinal section of a fixed-bed shaft reactor for the production of synthesis gas;

[0056] Fig. 2 shows a longitudinal section of another embodiment of a fixed-bed shaft reactor with a modified guide for the supplied oxygen-containing gas;

[0057] Fig. 3 is a longitudinal section of another embodiment of a fixed-bed shaft reactor with a special gas seal;

[0058] Fig. 4 shows a longitudinal section of a multi-part inner cylinder;

[0059] Fig. 5 shows a cross-section of another embodiment of a fixed-bed shaft reactor as a multiple gasifier. Fig. 1 shows a fixed-bed shaft reactor 1 designed for the thermochemical production of synthesis gas using a cocurrent process. The reaction chamber of the shaft reactor 1 is fed with carbonaceous substances 2 and / or solid biomass particles 3, with a conveying device 20 being used.

[0060] The reaction chamber is flowed through from top to bottom with the aforementioned substances, whereby the raw synthesis gas is generated in an autothermal gasification process by passing first through a fuel preheating zone 4, a pyrolysis zone 5 located below and finally an oxidation zone 6 by continuously metering in oxygen-containing gas 7 and, after passing through a reduction zone 8, is withdrawn at a synthesis gas outlet 9 at the lower end of the fixed-bed shaft reactor 1.

[0061] Below the reduction zone 8, the synthesis gas flows through an entrained-flow zone 12, which is separated from the reduction zone by a rotating grate 13 consisting of several at least partially rotating discs. The rotating grate 13 is designed to separate coarse slag and ash particles and discharge them from the process via a laterally arranged downpipe 24, so that the entrained-flow zone 12 is not clogged with coarse particles and, in addition, the free flow of the fixed bed from top to bottom is ensured.

[0062] The discs of the rotating grate 13 can be partially connected to the inner cylinder 10 and can rotate with it if necessary, while intermediate discs are rigidly connected to the reactor in a rotationally fixed manner.

[0063] As can be seen from Fig. 1, the oxygen-containing gas 7 is not introduced directly into the oxidation zone, but rather through a double-walled section of the reactor designed as a heat exchanger at the level of the entrained-flow zone 12. Water vapor 14 and / or carbon dioxide can be added to the oxygen-containing gas. Water 24 can also be added, although this does not necessarily have to occur at the location shown, but can in principle occur at any point in the gas flow up to the point of injection into the oxidation zone.

[0064] The heat exchanger is designed with heat transfer surfaces 18 on its side facing the entrained flow zone, via which heat is transferred from the hot synthesis gas in the entrained flow zone 12 to the cooler incoming process gas. As can be clearly seen from the figure, the heat exchanger is divided into several sections, with the cylindrical wall and the bottom area of ​​the entrained flow zone 12 enabling particularly effective heat transfer.

[0065] All heat transfer surfaces 18 can be ribbed to improve heat transfer, and flow-through heat exchanger channels can also be provided in projections to enlarge the effective heat transfer surfaces.

[0066] The oxygen-containing gas (process gas) 7 is then fed into a rotating inner cylinder 10. After flowing through the heat exchanger in the bottom region, it exits the cylinder through one or more passage openings 25 and enters a chamber 26. From there, it enters the inner cylinder 10 through surrounding openings 19. The double bottom ensures more homogeneous heating of the process gas before entering the inner cylinder 10.

[0067] With the help of the inner cylinder 10, the area comprising the oxidation zone (6), the reduction zone (8) and the entrained flow zone 12 is designed as an annular shaft reactor.

[0068] The inner cylinder 10 is set in rotation by means of a rotary drive M and has radially projecting attachments referred to as stirring fingers 16, which are capable of mechanically loosening the fixed bed in the manner of an agitator.

[0069] The inner cylinder 10 is designed as a hollow shaft to conduct the process gas, with the cavities continuing into the stirring fingers 16. These stirring fingers 16 are in turn provided with nozzle holes through which the process gas is metered into the oxidation zone 6. As a rule, a large number of such nozzle holes are provided, arranged at different radial positions. The stirring fingers 16 do not have to have a strictly radial course, but can also have an incline if necessary. The height of the stirring fingers can be adjusted in relation to the reactor, e.g. by means of a split inner cylinder whose parts can be adjusted telescopically or with different spacers. This will be discussed in more detail later in connection with Fig. 4.

[0070] The inner cylinder is guided through the bottom of the reactor by means of a suitable seal 27. Fig. 2 shows a further embodiment in which a dome 28 is provided instead of the double bottom with the intermediate chamber 26. This dome guides the oxygen-containing gas to the movable openings 119, which here are arranged further up at the upper end of the dome 28, into the interior of the rotating inner cylinder 10. From there, according to the variant from Fig. 1, it then reaches the stirring fingers 16, where it is injected into the oxidation zone 6 via nozzles. The oxygen-containing gas flows into the dome 28 via at least one passage opening 125 from the gas preheating zone 17 as part of the heat exchanger. The cylindrical outer wall of the dome forms an additional heat transfer surface 18, which can further improve the heat transfer to the oxygen-containing gas.

[0071] On the other hand, the dome 28 protects the inner cylinder 10 from excessive heating, since it is no longer directly exposed to the reaction products in the entrained flow zone 12 over a large area.

[0072] A seal 127 and a pivot bearing (not shown) of the inner cylinder are arranged at the upper end of the dome 28. The dome 28 thus allows the bearing point to be moved closer to the agitator fingers 16, which is advantageous due to the torques to be absorbed. Unlike the previously shown embodiment, the oxygen-containing gas is introduced into the heat exchanger area not from the side, but from below.

[0073] The embodiment shown in Fig. 3 largely corresponds to the embodiment in Fig. 2, but is equipped with a rotary union (A) with improved sealing. This takes into account the fact that overflow of the oxygen-containing gas from the interior of the dome 28 into the entrained flow zone 12 should be minimized, as such overflow can significantly impair the process, leading to partial oxidation of the produced synthesis gas in the entrained flow zone 12 and, accordingly, significantly deteriorating its quality.

[0074] The seal is designed as an axial mechanical seal B, the friction pair of which consists of a first sealing body C below the grate 13, which rotates with the inner cylinder, and a second static sealing body D, which is arranged on the dome 28 in a rotationally rigid manner. The gap visible in the figure is closed in practice, the two axial sealing surfaces of the two sealing bodies C, D, which are made of a suitable material, lie on one another during operation and seal the interior of the dome 28 against the entrained flow zone 12 in a gas-tight manner.

[0075] The contact pressure between the sealing surfaces can be built up by a spring element in the area below the heat exchanger, which presses the entire inner cylinder 10 with the rotating sealing body C downwards against the static sealing body D with a defined contact force. The rotary bearing of the inner cylinder 10 can be taken over by the static sealing body D, whose radial inner wall interacts with a circumferential surface of the inner cylinder 10.

[0076] In all variants shown, a stirring element 21, which is moved continuously or discontinuously, is provided in the area of ​​the preheating zone 4. The stirring element can also be used to detect fill levels by measuring the torque of the stirring element. This measured value can be used as a control variable for the conveying device 20 to further convey carbon-containing substances.

[0077] The stirring fingers of the stirring element 21 can be designed like paddles with an orientation that allows for compaction of the material. This can potentially prevent hollow fires.

[0078] An exemplary multi-part structure of the inner cylinder 10 is described with reference to Fig. 4, whereby most of the parts from the preceding figure (Fig. 3) have been omitted for clarity. In addition to a cylindrical tubular body 10 as the main element, the inner cylinder has separately designed stirring fingers 16, which also function as nozzle carriers (single- or multi-part) for introducing the process gas into the oxidation zone. These are placed on top of the tubular body 10, creating a gas passage to the nozzle openings on the stirring fingers.

[0079] Above the nozzle holder is an end cap (E), which is connected to a pull rod (F). The pull rod (F) clamps the end cap (E) against the nozzle holder (16), which in turn clamps the nozzle holder against the inner cylinder (10), forcing the inner cylinder (10) downwards. This creates the axial clamping force for the rotary union (A) and presses the sliding seal surfaces (C and D) together, allowing the sliding seal (B) to operate gas-tight. Spacers can be inserted between the nozzle holder 16 and the tubular body to adjust the height of the nozzle holder 16, if desired.

[0080] The tension rod (F) is advantageously led out of the reactor in the lower section, where it can be preloaded with a defined preload force, e.g., a coil spring (G). Preload can also be achieved using weights or a suitably heavy inner cylinder; this can be done in addition to the spring's tension force if necessary.

[0081] The connection between the tie rod (F) and the end cap (E) is preferably designed in the form of a thread. This allows the tie rod (F) to be released from the end cap by turning it, thus enabling disassembly of the end cap (E) and nozzle carriers (16) without the need for complex assembly work inside the shaft furnace.

[0082] During normal operation, the nozzle holders (16) and the end cap (E) are clamped onto the inner cylinder (10) by the tension rod (F).

[0083] The pull rod (F) can also be used as an electrical conductor, for example to supply power to an ignition unit in the end cap or in the area of ​​the nozzle carrier or to an air preheater in the inner cylinder.

[0084] If necessary, technical oxygen can be added to the process gas, which is usually air, or pure technical oxygen can be used as the process gas, provided that the substances to be gasified require or permit this.

[0085] Finally, alkaline earth-containing substances, preferably calcium-containing substances, and particularly preferably calcium hydroxide and / or calcium oxide, can also be added to the carbonaceous substances to be gasified to bind acid gases, halogens, sulfur compounds, and heavy metals released in the fixed-bed shaft reactor 1. This can expand the range of usable raw materials to include, among other things, critical waste fractions.

[0086] The invention is not limited to one of the previously described embodiments, but can be modified in a variety of ways. For example, the reactor can also be designed as a multiple reactor with several shafts arranged side by side, as shown in cross-section in Fig. 5. This makes the entire system scalable and, with the same basic technology, can be easily scaled for different volume flows to be gasified. Overlapping of the stirring fingers 116 in the inner cylinders 110 and the stirring element is also possible; these can interlock radially, with a synchronized drive being provided.

[0087] In the grate area, it is possible to arrange the discharge pipe 23 as a large-diameter discharge opening centrally between the shafts of the multiple carburetors, which improves the discharge process. Multiple carburetors 110 can preferably be designed in a square quadruple arrangement, as shown in Fig. 5, but other arrangements are also possible, e.g., double with two shafts next to each other, six-fold with an arrangement of 3 x 2 shafts, 4 x 3 shafts, nine shafts in a square 3 x 3 arrangement, etc.

[0088] All features and advantages arising from the claims and the description, including design details, spatial arrangements and method steps, can be essential to the invention both individually and in a wide variety of combinations.

[0089] Reference symbol list

[0090] 1 fixed-bed shaft reactor

[0091] 2 Carbon-containing synthetic substances

[0092] 3 Biomass

[0093] 4 Fuel preheating zone

[0094] 5 Pyrolysis zone

[0095] 6 Oxidation zone

[0096] 7 oxygen-containing gas

[0097] 8 Reduction zone

[0098] 9 Synthesis gas outlet

[0099] 10, 110 inner cylinder

[0100] 11 Annular shaft reactor

[0101] 12 Airflow zone

[0102] 13, 113 disc rust

[0103] 14 Water vapor

[0104] 15 Carbon dioxide

[0105] 16, 116 stirring fingers / nozzle holders

[0106] 17 Gas preheating zone

[0107] 18 Heat transfer surface

[0108] 19, 119 moving openings

[0109] 20 conveyor system

[0110] 21 Stirring element

[0111] 22 alkaline earth substances

[0112] 23, 123 discharge opening

[0113] 24 Water

[0114] 25, 125 passage opening

[0115] 26, 126 Chamber

[0116] 27, 127 Seal

[0117] 28 Cathedral

[0118] 100 fixed-bed shaft reactor (multiple gasifiers)

[0119] 150 reaction chambers

[0120] A rotary union

[0121] B Sealing

[0122] C rotating sealing body D static sealing body

[0123] E End cap

[0124] F threaded rod

[0125] G tension spring

Claims

Patent claims 1. Apparatus for the thermochemical production of synthesis gas with a fixed-bed shaft reactor (1; 100) operated in cocurrent, the reaction chamber of which is flowed through from top to bottom with carbon-containing synthetic substances (2) and / or with solid biomass particles (3), and in which a raw synthesis gas is generated by passing through a fuel preheating zone (4), pyrolysis zone (5) and a downstream oxidation zone (6) by continuously metering in oxygen-containing gas (7) in an autothermal gasification process, and after further flowing through a reduction zone (8) is withdrawn at the lower end of the fixed-bed shaft reactor at (9) together with fly ash, wherein the raw synthesis gas, after leaving the reduction zone (8), flows through an entrained flow zone (12) located below the reduction zone (8) in the reactor, characterized in thatthat an inlet for the oxygen-containing gas (7) is provided below the reduction zone (8) and the wall of the reactor in the entrained flow zone (12) in the reactor is at least partially double-walled as a heat exchanger with at least one heat transfer surface (18), wherein the oxygen-containing gas is passed through a gas preheating zone (17) formed in the heat exchanger, so that the outflowing raw synthesis gas is cooled in the entrained flow zone (12) and the oxygen-containing gas is heated.

2. Device according to claim 1, characterized in that a gas guide for the oxygen-containing gas (7) is provided between the heat exchanger in the entrained flow zone (12) and the oxidation zone (6).

3. Device according to claim 1 or 2, characterized in that the outer wall and / or the bottom of the entrained flow zone (12) are at least partially double-walled as a heat exchanger with heat transfer surfaces (18).

4. Device according to claim 1, 2 or 3, characterized in that the heat transfer surfaces are formed with ribs and / or projections with internal flow channels for the oxygen-containing gas to enlarge the effective surfaces.

5. Device according to one of the preceding claims, characterized in that the reactor shaft is designed as an annular shaft reactor (11) by means of an inner cylinder (10), wherein the inner cylinder (10) is located in the center of the oxidation zone (6), the reduction zone (8) and the entrained flow zone (12).

6. Device according to claim 5, characterized in that the inner cylinder (10) has a rotary drive and radially projecting attachments to enable a mechanical movement of the fixed bed by the rotational movement of the inner cylinder (10) during the gasification process.

7. Device according to claim 5 or 6, characterized in that the quotient formed from the inner diameter of the oxidation zone (6) and the outer diameter of the inner cylinder (10) is less than 20, preferably less than 15 and particularly preferably less than 10.

8. Device according to claim 6 or 7, characterized in that the vertical inner cylinder (10) is designed as a hollow shaft and in the region of the oxidation zone is equipped with a plurality of hollow stirring fingers (16) projecting into the fixed bed and provided with nozzle holes as attachments and is firmly connected, through which the oxygen-containing gas (7) is passed and dosed into the oxidation zone (6) via the nozzle holes of the stirring fingers (16).

9. Device according to claim 8, characterized in that the vertical inner cylinder is surrounded by a dome (28) in the region of the entrained flow zone (12).

10. Device according to claim 9, characterized in that a rotary bearing of the inner cylinder (10) is arranged at the end of the mandrel (28) facing the stirring fingers 16.

11. Device according to claim 9 or 10, characterized in that the dome (28) is formed as part of the heat exchanger and is flowed through by the oxygen-containing gas, its peripheral surface forming a heat transfer surface (18).

12. Device according to one of claims 8 to 11, characterized in that the rotating driven inner cylinder (10) has openings (19) in its walls, through which the oxygen-containing gas (7) is introduced into the heat exchanger after flowing through the heat exchanger via moving openings (19) in the wall of the rotating inner cylinder (10).

13. Device according to claim 11 or 12, characterized in that in the region of a rotary feedthrough (A) on the head of the dome (28) an axial mechanical seal (B) is provided, which has a rotating sealing body (C) rigidly connected to the inner cylinder (10) and a static sealing body rigidly connected to the dome (28).

14. Device according to one of claims 8 to 13, characterized in that the height of the nozzle holes in the reactor can be changed to adjust the oxidation zone and the reduction zone.

15. Device according to one of claims 6 to 14, characterized in that the reduction zone (8) with the fixed bed contained therein is separated from the entrained flow zone (12) by a disc grate (13) with defined gaps between the discs as a passage for the raw synthesis gas into the entrained flow zone and as a barrier for coarse solid particles, wherein parts of the disc grate are firmly connected to the vertical inner cylinder (10) as an attachment and a discharge opening (23; 123) is provided for the coarse solid particles.

16. Device according to one of the preceding claims, characterized in that the carbon-containing synthetic substances (2) and / or biomasses (3) are moved continuously or discontinuously in the fuel preheating zone (4) with the aid of an agitator (21), wherein the fill level of the carbon-containing synthetic substances (2) and / or biomasses (3) in the fuel preheating zone (4) is detected by measuring the torque of the agitator (21) and the measured value is used as a control variable for regulating the feed rate of the carbon-containing synthetic substances, wherein the agitator fingers of the agitator are geometrically designed in such a way that they increase compaction of the material downwards in the direction of flow and thereby prevent hollow fires.

17. Device according to one of claims 5 to 16, characterized in that the fixed-bed shaft reactor (100) has a plurality of reaction chambers (150) arranged parallel to one another, in each of which an inner cylinder (110) is arranged.

18. Device according to claim 15 and 17, characterized in that one of the number of A corresponding number of disc grates (113) is provided for the reaction chambers and a discharge opening (123) is arranged centrally between two or four disc grates (113).

19. A process for the thermochemical production of synthesis gas in a fixed-bed shaft reactor (1) operated in cocurrent, the reaction chamber of which is flowed through from top to bottom by carbon-containing synthetic substances (2) and / or by solid biomass particles (3), and in which a raw synthesis gas is generated by passing through a fuel preheating zone (4), pyrolysis zone (5) and a downstream oxidation zone (6) by continuously metering in oxygen-containing gas (7) in an autothermal gasification process, and after further flowing through a reduction zone (8) is withdrawn at the lower end of the fixed-bed shaft reactor at (9) together with fly ash, wherein the raw synthesis gas, after leaving the reduction zone (8), flows through an entrained flow zone (12) located below the reduction zone (8), characterized in thatthat the oxygen-containing gas (7) is supplied via an inlet below the reduction zone (8) and is passed through a gas preheating zone (17) in the region of the entrained flow zone (12) in the reactor formed heat exchanger with at least one heat transfer surface, wherein the outflowing raw synthesis gas is cooled in the entrained flow zone (12) and the oxygen-containing gas is heated.

20. Process according to claim 19, characterized in that the oxygen-containing gas is led from the heat exchanger in the entrained flow zone (12) into the oxidation zone (6), where it is introduced into the reactor.

21. Method according to claim 19 or 20, characterized in that air and / or technical oxygen or a mixture thereof is used as the oxygen-containing gas (7).

22. Method according to one of claims 19 to 21, characterized in that water vapor (14) and / or gaseous carbon dioxide (15) is added to the oxygen-containing gas (7).

23. Method according to claim 22, characterized in that the water vapor is generated by dosing water (24) into the gas preheating zone (17) by evaporation at the heat transfer surface (18) and is mixed directly into the oxygen-containing gas (7) in the gas preheating zone (17).

24. Method according to one of claims 19 to 23, characterized in that alkaline earth-containing substances (22), preferably calcium-containing substances and particularly preferably calcium hydroxide and / or calcium oxide, are added to the carbon-containing synthetic substances (2) and / or biomasses (3) for binding acid gases, halogens, sulfur compounds and heavy metals released in the fixed-bed shaft reactor (1).

25. Method according to one of claims 19 to 24, characterized in that the pressure difference across the fixed bed in the fixed bed shaft reactor (1) is measured and that the measured value is used as a control variable for regulating the rotational movement of the vertical inner cylinder (10) and the attachments of the vertical inner cylinder (10).

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