EP1323809B1 - Co-current shaft reactor - Google Patents

Abstract

Direct flow shaft reactor comprises a vertical shaft body (10) for drying, heating and gasifying the material to be treated and having a feed opening (28) for introducing the material; a receiving body (20); a gas removing device (26) connected to the shaft body and/or the receiving body; and a gas feeding device (36) connected to the shaft body for introducing gas to the shaft and for drying the material. <??>Direct flow shaft reactor comprises a vertical shaft body (10) for drying, heating and gasifying the material to be treated and having a feed opening (28) for introducing the material; a receiving body (20) connected to the shaft body for receiving melted material; a gas removing device (26) connected to the shaft body and/or the receiving body; and a gas feeding device (36) connected to the shaft body for introducing gas to the shaft and for drying the material. Preferred Features: The gas feeding device and the gas removing device are connected together via a heat exchanger (56). The gas feeding device is connected to a heater (64). A sluice arrangement (12) is connected to the feed opening and has a sluice chamber. The gas feeding device is connected to the sluice chamber.

Description

The present invention relates to a DC shaft reactor for melting and gasifying feedstocks of different types and consistencies, such as pollutant-free and / or contaminated wood, domestic and bulky refuse, substitute fuels, pelleted dusts or animal meal, plastics, industrial and commercial waste.

In shaft reactors, a synthesis gas which is suitable for generating electrical energy and heat and / or is used as a basis for synthesis processes can be produced. The solid product formed is a non-leachable slag and a material processable metal phase or a non-recoverable liquid phase, which is available for further processing.

DE 43 17 145 C1 describes a method and apparatus for degassing waste materials based on a coke-heated countercurrent shaft furnace. Here, the resulting dust-containing gas is completely removed and burned in the underlying melting and overheating zone with oxygen at high temperatures. The countercurrent flow of the gas through the downwardly moving bed and the suction between the Kreislaufgasausaugung and the recirculation gas supply result in a variety of practical problems. The result is short circuit flows in the shaft and insufficient heat transfer to the upper shaft area, which creates a contaminated gas with tar and dust components. As a result, a complex gas treatment and purification is necessary. Furthermore, there is the danger that tar and dust deposits disrupt the continuous operation. Another permanent danger for a stable operation is the guidance of pyrolysis gas and degassing gas with tar and dust particles in pipes. Partial or complete dislocation of the lines with tar-dust deposits result in uneven circulating gas guidance and thus uneven process control in the shaft furnace.

In the DE 196 40 497 C2 a coke-heated Kreislaufgaskupolofen for material and / or energy recovery of waste materials is described. It consists of a vertical furnace shaft with below-the-aeration large-volume Kreislaufgasabsaugöffnungen, which are connected by channels and nozzles with the melting and superheating zone, above which a large-volume excess gas discharge level, the resulting gas from the process. In this case, the furnace shaft part is narrowed in cross-section between the circulation gas and excess gas suction openings. The heat transfer takes place as well as in DE 43 17 145 C1 by the countercurrent principle to the feedstock rising process gases. The multiple countercurrent flow of the gas through the downwardly moving bed, despite some modifications due to cross-sectional constriction in the shaft and cross-sectional widening in the gas outlet does not allow the processing of a wide range of feedstock.

It continues in DE 198 16 864 A1 a cycle gas cupola is described in which an excess gas suction is arranged below the melting and superheating zone. This results in a countercurrent gasification and heat transfer in the upper furnace shaft area, where the gas is sucked by means of large-volume openings and through Channels / nozzles is passed into the melting and overheating zone. In the subsequent DC gasification, the gas is reduced at high temperatures and split longer-chain hydrocarbons. This selected arrangement reduces the negative influence of short-circuit currents. The spatial proximity of the endothermic processes to the hearth area and the large-volume excess gas extraction draws the necessary heat from the melt in order to ensure the necessary liquid discharge of melt under all operating conditions.

In DE 100 07 115 A1 For example, a reactor for gasifying and / or melting feedstocks with a feed, pyrolysis, melt and superheat section is described. The pyrolysis section has a cross-sectional widening as a gas feed space, into which at least one combustion chamber opens with at least one burner, through which hot combustion gases are fed to a forming bulk cone. Furthermore, high-energy media are introduced by means of upper and lower injection means in the region of the melting and superheating zone and above the melt by means of oxygen lances and / or nozzles. The disadvantage of this device is increased by the bulk cone

Reactor surface in the area of cross-sectional expansion of pyrolysis, since heat losses occur. Furthermore, in the bulk cone, the larger pieces of feedstock roll to the reactor wall, causing a disadvantageous segregation occurs. The result is a strong one-sided melting of the Ofenausmauerung, which leads to a shorter service life of the reactor. As a result of the segregation, preferred flow channels for the incoming gases are formed in the bed. This has the consequence that form various heterogeneous reaction zones, which lead to fluctuating gas qualities.

Out US 4,813,179 is a DC-shaft reactor for melting and gasifying feed known, the shaft body a Lock area is upstream with locks. The lock area ends at a screw conveyor, which introduces feed into the shaft body. The introduced feed is then conveyed in the vertical direction through a feed opening of the shaft body by means of a further screw conveyor to a rotating distribution plate, which spreads the feed over the entire cross-sectional area of the shaft body. In the area of the further screw conveyor, preheated reaction gas is fed for drying the feedstock via a gas supply device.

In general, it can be assumed that in the case of feedstocks with high ignition points in poor heat conduction and in the case of substances with high humidity, the heat supplied in the pyrolysis section is not sufficient Heating and pyrolysis or degassing of the substances leads. The degassing and gasification processes shift to the melting and overheating section, reducing the reaction time to destroy all the tars and oils that form in the form of longer-chain hydrocarbons.

All of the above described shaft reactors can only be used for a small range of starting materials. Furthermore, a significant amount of energy must be supplied for gasifying the feedstocks. This is done by different nozzle systems, which are arranged in the vertical shaft bodies, as well as introduced via together with the bulk material in the shaft body fuel, such as coke or the like. Furthermore, in known shaft reactors, irrespective of whether they operate on the cocurrent or countercurrent principle, there is the problem that the withdrawn gas is heavily loaded with particles and thus has to be filtered before further processing, for example.

The object of the invention is to provide a direct current shaft reactor, with which useful gases, in particular combustible useful gases with a low particle load, can be produced even when different starting materials are used, the energy content of which can be used for the direct current shaft reactor.

The object is achieved according to the invention by the features of claim 1.

The inventive DC-shaft reactor for melting and gasifying feedstock, has a vertical shaft body. Within the shaft body, the feedstock is dried, heated and gasified. The shaft body can thus usually be subdivided into the areas of drying zone, degassing zone and gasification zone. The shaft body is followed by a receiving body, which serves to receive molten feedstock. Within this body is the Melting zone of the reactor formed. The shaft body and / or the receiving body are connected to a gas discharge device for discharging the Nutzgase generated within the reactor. In particular, the discharge device is arranged in the region between the shaft body and the receiving body and designed as a tube. Further, the vertically oriented shaft body has a feeder through which the feedstock is fed to the shaft reactor.

According to the invention, a gas supply device for supplying gas into the shaft body is connected to the shaft body. The supplied gas, which is preferably air or oxygen-enriched air, serves to dry the feedstock. In order to achieve a good and effective drying of the feedstock, the gas supplied is preheated according to the invention. For preheating the gas, the gas supply device according to the invention is connected to the gas discharge device. The discharged from the reactor hot gas is thus used according to the invention for preheating the gas supplied to the shaft body. The feed opening of the reactor is followed by a lock arrangement which controls the introduction of the feedstock. In the area of the lock arrangement, at least part of the gas supply device is connected to the lock chamber. The inventive use of the discharged gas as an energy source means that no additional energy is required for preheating the gas and the feed already undergoes a first drying in the lock assembly. The lock arrangement is thereby additionally used for drying the feedstock. Another essential advantage of the invention is that heat is removed from the discharged gas. This simplifies the further processing or use of this gas.

Due to the preheating of the feedstock, which according to the invention already takes place immediately after feeding the feedstock in the lock arrangement, a larger product range can Feedstock can be processed in the shaft reactor, since the feedstock is heated more during his stay in the shaft reactor and thus even with less processable materials degassing and gasification can be achieved. In particular, this also achieves that within the reactor better degassing and gasification takes place, so that the Nutzgas has fewer particles. In particular, it is possible due to the inventive design of the DC-shaft reactor to produce Nutzgase having a significantly lower oil and tar content and a significantly lower pollutant content.

The introduction of feed into the shaft body via the lock assembly. With the help of the lock arrangement can be ensured that, for example, only a limited amount of ambient air enters the shaft reactor via the feed opening. This allows better control of the process within the shaft reactor. The lock arrangement preferably has at least one lock chamber. Thus, a first lock gate is opened to introduce the feed into the lock chamber. Then this first lock gate is closed, so that the lock chamber is closed. In this state, possibly contained air can be sucked out of the lock chamber and / or replaced by another gas. Subsequently, the second lock gate, which leads in the direction of the interior of the shaft reactor, opened and the feed material passes from the lock chamber into the reactor.

Advantageously, the lock arrangement is designed so that the introduction of feed into the DC shaft reactor takes place almost free of freeze or low-shear. This reduces the risk of larger pieces of feedstock rolling to the reactor wall and segregation of the feedstock. The adverse consequences of demixing, such as melting of Ofenausmauerung, emergence of flow channels for the incoming gases and fluctuating gas qualities due to different reaction zones are thereby greatly reduced. A low-shear introduction of material into shaft reactors can be achieved, for example, by the fact that the reactor shaft, which follows the lock arrangement, has a similar cross-sectional geometry. Furthermore, the drop height of the supplied goods should be as low as possible. In particular not higher than three times the height of the feed in the lock arrangement. In addition, the second floodgate should open as quickly as possible, so that the underside of the falling feed remains as horizontal as possible.

Furthermore, the feedstock in the lock assembly should not as far as possible already contain a bulk cone. This can be achieved, for example, in that the lock chamber in the lock arrangement is completely filled with feed material and, as the first lock gate is closed, the feed which does not fit into the lock chamber is cut off from the feed material to be introduced. For this purpose, the first lock gate is designed as a slide with cutting edge in an advantageous manner. As a result, the feedstock to be introduced almost corresponds to the geometry of the lock chamber and in particular has almost no bulk cone on.

Thus, the second lock gate can be opened as quickly as possible, it is carried out in an advantageous manner as a flap or slide.

Figur 1

zeigt eine schematische Seitenansicht eines Gleichstrom-Schacht-Reaktors.

Figur 2

zeigt eine schematische Seitenansicht einer bevorzugten Ausgestaltung einer Schleusenanordnung.

The invention will be explained with reference to a preferred embodiment with reference to the accompanying drawings.

FIG. 1

shows a schematic side view of a DC reactor shaft.

FIG. 2

shows a schematic side view of a preferred embodiment of a lock assembly.

The DC shaft reactor has a shaft body 10. In the exemplary embodiment illustrated, the shaft body 10 can be subdivided into a lock arrangement 12, a drying zone 14 adjoining the lock arrangement 12, a degassing zone 16 adjoining the drying zone 14, and a gasification zone 18 connected thereto. At the gasification zone 18 of the shaft body 10, a receiving body 20 connects, which serves to receive molten feedstock 22. In the boundary region between the gasification zone 18 and the receiving body 20, the cross-section of the receiving body is widened, so that an annularly formed gas collecting space 24 is formed, which surrounds the lower part of the gasification zone 18. The gas collecting space 24 is connected to a gas discharge device 26 designed as a pipe in the illustrated embodiment.

The feed is introduced through a supply port 28 into the well body 10 via the gate assembly 12. The feeding of the feed material takes place via the lock arrangement 12 in order to prevent the introduction of large amounts of ambient air, by means of which the melting and gasification process can be influenced in an uncontrolled manner. For this purpose, the lock arrangement 12 has two lock devices or lock gates 30, 32, between which the lock chamber 34 is formed, the lock chamber 34 already being part of the shaft body 10.

In the illustrated embodiment, a gas supply device 36 is provided in the region of the drying zone 14 of the shaft body 10. The gas supply device 36 has a ring conduit 38 surrounding the shaft body 10, which is connected to a plurality of nozzles 40 distributed uniformly around the circumference. About the gas feeder 36 is the feed in Area of the drying zone 14 preferably hot air, which may optionally be enriched with oxygen, fed to dry the feedstock.

In the subsequent to the drying zone 14 degassing zone 16, a further gas supply means 42 is arranged, which also has a surrounding the shaft body 10 ring line 44. The ring line 44 is connected to a plurality of circumferentially preferably uniformly distributed nozzle 46. High-energy gases, oxygen, air or other gases suitable for controlling the melting and gasification process can be supplied to the feedstock via the gas feed device 42.

Further nozzles 48 are provided in the gasification zone 18. High-energy gas or other gases or substances controlling the melting and gasification process can in turn be supplied via the nozzles 48. Likewise, instead of the nozzles 48, it is also possible to provide burners which directly supply heat to the feedstock in the gasification zone 18. The end region of the shaft body 10, which is rotationally symmetrical with respect to the longitudinal axis 50, has a slightly tapered conical shape, so that the feed material is retained somewhat in the region of the gasification zone 18.

In a side wall 52 of the receiving body 20 a plurality of circumferentially distributed nozzles 54 are further arranged. The nozzles 54 serve to introduce high-energy gases or corresponding substances. By the nozzles 54 it is ensured that the melt 22 remains liquid. Likewise, burners may be provided instead of the nozzles 54.

The gas supply device 36 is connected to the gas discharge device 26. For this purpose, the tube of the gas discharge device 26 through which the hot gases produced in the reactor are discharged, to a heat exchanger 56. The discharged gases or Nutzgase flow through the heat exchanger 56 and are then discharged from a pipe 58 preferably for further processing. Further, with the heat exchanger 56 a Pipeline 60 connected. Through the pipe 60, air or other gas is passed into the heat exchanger 56, takes in the heat exchanger 56 heat from the useful gas and is discharged through a pipe 62 back out of the heat exchanger. The tube 62 is then connected via a heater 64 and a pipe 66 to the ring line 38 of the gas supply device 36. The heating of the gas supplied to the feed material by the gas feed device 36 in the region of the drying zone 14 is thus preferably preheated in operation exclusively by the heat of the useful gases with the aid of the heat exchanger 56. By means of the heating device 64, which may be, for example, an electric heater or a burner, the gas to be supplied via the gas supply device can be additionally heated. In particular, during the start cycle of the reactor in which no hot useful gases are still discharged through the gas discharge device 26 or the temperature of these groove gases is not high enough, the heater 64 can be used to heat the gas.

According to the invention, a part 35 of the gas feed device 36 is connected to the shaft body 10 in the region of the lock arrangement 12. Through this connection, the feedstock is already subjected to a first drying in the lock assembly 12.

Preferably, a side wall 68 of the lock assembly 12 is double-walled. In this way, heating and thus drying of the feed material in the lock chamber 34 can be achieved by passing a hot medium through the double-walled side wall 68. This is preferably air or another gas, which is likewise preheated by the useful gas, preferably with the aid of the heat exchanger 56.

The ideal material input preferably requires a homogeneous mixture, in particular when adding additives such as coke and lime. The entry is carried out according to the invention centrally on the axis of the reactor. Of the Reactor should be kept as full as possible during operation. A level monitoring is therefore preferably mounted directly below the lock gate 32. The filling takes place in a high clock rate. These measures simultaneously reduce the false air intake and improve the pressure maintenance in the overall system.

According to the invention, the areas of the lock arrangement 12, the drying zone 14 and the degassing zone 16 are preferably cylindrical or slightly conically widening down to the gasification zone 18. The transition between the zones takes place without a step-shaped or sudden cross-sectional enlargement, i. the transition is the same cross-section and without formation of shake-free cavities, steps or edges.

The drying zone 14 can also be designed with double walls, in particular for larger types. This allows indirect heating of the Gutsäule inside or ensuring a uniform temperature on the wall and a reduction of condensation phenomena on the inside. The heat transfer medium is preferably also hot air used. The use of standing up at the end of the process flue gas is also possible.

When heating the starting material takes place in the drying zone 14, the evaporation of the water. The temperature in the estate rises only slightly above 100 ° C. With increasing temperature adsorbed gases such as nitrogen and carbon dioxide are released in the further course, which are not caused by cleavage reactions. At the latest here can be spoken of the degassing. Above 250 to 300 ° C then begins the development of gases and vapors, which are distilled low molecular weight compounds and first cleavage products. A further increase in temperature causes the course of reactions that lead to the formation of methane and hydrogen.

The degassing zone 16 can also be designed double-walled in continuation of the drying zone 14.

In the lower third of the drying and degassing zone 14,16 results in a range in which the internal reactor temperature is greater than the hot air temperature. Here, the double-walled version can be replaced by a silicate brick lining. An embodiment of the entire drying and degassing zone 14,16 with a ramming mass, even with a double-walled design, is advantageous. Less wear of the steel construction shell is offset by lower heat transfer and lower thermal shock resistance.

In the further heating of the pouring column from about 700 ° C is carried out in addition to the cleavage of the fuel under the influence of heat, the heterogeneous reaction between the fuel and the unreacted oxygen in the air.

The gasification zone 18 is the main reaction zone within the shaft reactor. Here, at temperatures of 1,200 to 1,400 ° C, the material and energetic conversion of the solids. The solid fuel produces gases and solid products from coke to ash. For the complete and uniform reaction, it is crucial that a homogeneous bed is flowed through uniformly by the degassing gas already produced and the gasification agent to be introduced here. The gasification zone 18 must have a sufficient height for these reasons. This is achieved in that the gasification zone 18 is formed as a straight cylindrical portion with transition into a conical reduction of the cross section or immediately as an increasing taper. Since the material grain is reduced by the material transformations and related destructive forces, the cavities increase within the pouring column. By reducing the size of the shaft cross section in this area, the sinking speed of the Material column are evened out, flow channels are destroyed and the formation of larger voids in the bed is avoided.

In continuation of the degassing zone 16 above, the region of the gasification is likewise lined with a silicate mass.

The lower cylindrical or tapered region of the gasification region 18 projects into the molten zone 20. On this part, the Schüttsäule located above it at least partially, at the same time prevail there high temperatures. To secure the mechanical strength and the protection against excessively high temperatures, cooling takes place by means of indirect water cooling in the shaft wall 70.

The gas flowed through the zone of high-temperature gasification in co-current with the feed material. The longer-chain hydrocarbons formed from the expired degassing and thermolysis reactions were thermally split here and at the same time participated in the gasification processes taking place. The result is a combustible gas average calorific value with the main components carbon monoxide, carbon dioxide, hydrogen and water vapor without constituents of condensable hydrocarbons. Many of the chemical reactions that have taken place are endothermic. The temperature of the gas as well as the bed thus decreases.

Below the water-cooled region of the gasification region 18, the gas undergoes a deflection by about 180 ° and enters the shake-free space 24. By the above-described endothermic processes, the gas has a temperature of about 1,000 ° C. After a certain gas calming and -gleichmäßigung the gas is sucked out of the reactor above.

The gas collection chamber 24 is already part of the melting zone 20, which is substantially further up than the projecting gasification zone 18 above. The Cylindrical melt zone 20 tapers conically downward and closes with the bottom plate above which the molten phase collects.

The melting zone 20 is provided in its entirety with a multi-layer ramming mass or equipped with a lining. The reason for this is the necessary high temperatures. Only in the area of the gas collection room a lining may not be necessary.

The completely degassed and coked solid is already partially sintered or melted and sinks from the gasification zone 18 into the molten zone 20.

Integrated into the molten zone 20 is a plane with a plurality of oxygen nozzles or injectors and / or oxidatively operated burners 54, which are also distributed symmetrically on the axis.

The supply of gas with a high oxygen content leads to strong exothermic reactions with the gas and the solid from the gasification zone 18. This results in temperatures which are significantly above the melting point of the material, usually about 1400 ° C to 1600 ° C. , In the area of the oxygen nozzles even hot temperature zones of 1800 to 2000 ° C arise. Under these conditions and by the addition of slag formers and / or materials which lower the melting point, all inorganic pollutants are safely melted.

The molten material collects as a melt at the bottom of the reactor. The emptying of this liquid melt takes place as usual in the foundry via a tap hole and a gutter 72. A design with a forehearth or siphon is possible.

With sufficiently large design and appropriate residence time of the melt, the melt will separate into a heavy metal-containing phase and a slag floating on it. Here it is possible to gain a usable metallic phase and a slag via different high emptying. The product slag contains no organic substances and the inorganic components are stably incorporated into a silicate matrix. The use as a material for harbor, landfill and road construction are known, as is possible the production of special molds and products, as they are common in the glass industry.

A preferred embodiment of the lock arrangement 12 is that the second lock gate 32 is designed as a quick-opening slide ( Fig. 2 ). For this purpose, the floodgate 32 is designed in particular in several pieces. When opening the lock gate 32, the feed material contained in the lock chamber 34 falls evenly into the drying zone 14 of the shaft body 10. Previously, the feed was pre-dried with the part 35 of the gas feeder 36 connected to the lock chamber 34. In the event that the shaft body 10 is filled with so much feed material that a portion of the feed material protrudes into the lock chamber 34, designed as a slide second lock gate 32 is advantageously provided with a cutting edge. As a result, the part of the feed material protruding into the lock chamber 34 can be cut off when the second lock gate 32 is closed, as a result of which the lock chamber 34 can be closed again.

In order that almost no pour cone is formed in the lock chamber 34, the lock chamber 34 is completely filled and the part of the feed material which does not fit in is cut off. For this purpose, the first lock gate 30 is designed as a slide with a cutting edge, which separates the upper part of the feed from the lock chamber 34. The first lock gate 30 can also be made in several pieces in this embodiment.

For introducing feed into the shaft body 10, the second lock gate 32 is initially closed and the first lock gate 30 is opened. As a result, feed material enters the lock chamber 34. After closing the first lock gate 30, the second lock gate 32 is opened, whereby the feed material falls into the shaft body 10. At the same time, additional feed material can already be introduced through the feed opening 28 which is provided on the first lock gate 30. Thereafter, the filling cycle begins again.

Claims (10)

1. A co-current shaft reactor for melting and gasifying feedstock, comprising

   a vertical shaft body (10) for drying, heating and gasifying the feedstock, said shaft body (10) comprising a feed opening (28) for feeding the feedstock,

   a receiving body (20) adjoining the shaft body (10), for receiving molten feedstock (22),

   a gas discharge means (26) for discharging gases produced, said gas discharge means being connected with the shaft body (10) and/or the receiving body (20),

   a gas feed means (36) connected with the shaft body (10), for feeding gas into the shaft body (10) to dry the feedstock, said gas feed means (36) being connected with the gas discharge means (36) to heat up the gas, and

   a lock arrangement (12) comprising at least one lock chamber (34),
   characterized in that

   the lock arrangement (12) is arranged downstream of the feed opening (28), and

   at least a part (35) of the gas feed means (36) and/or at least a part of the gas discharge means (26) is connected with the lock chamber (34).
2. The co-current shaft reactor of claim 1, characterized in that the gas feed means (36) and the gas discharge means (26) are interconnected via a heat exchanger (56).
3. The co-current shaft reactor of claim 1 or 2, characterized in that the gas feed means (36) is connected with a heating means (64).
4. The co-current shaft reactor of one of claims 1-3, characterized in that the lock arrangement (12) is arranged substantially asymmetrically with respect to the shaft body (10).
5. The co-current shaft reactor of one of claims 1-4, characterized in that a side wall (68) of the shaft body (10) is of a double-walled structure, especially in the region of the lock arrangement (12) for heating the feedstock.
6. The co-current shaft reactor of claim 5, characterized in that the double side wall (68) is connected with the gas feed means (36).
7. The co-current shaft reactor of one of claims 1-6, characterized in that, in the region of the drying zone (14), the cross-sectional area of the shaft body (10) is similar to the cross-sectional surface of the lock arrangement (12).
8. The co-current shaft reactor of one of claims 1-7, characterized by a first lock gate (30) which is designed in particular as a slide with a cutting edge, and/or a quick-opening second lock gate (32) which is designed in particular as a slide with a cutting edge.
9. The co-current shaft reactor of claim 8, characterized in that the first lock gate (30) and/or the second lock gate (32) are of multi-part design.
10. The co-current shaft reactor of one of claims 1-9, characterized in that the drop height of the feedstock introduced via the lock arrangement (12) is not higher than three times the height of the lock chamber (34).

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