WO2024134230A1

WO2024134230A1 - Gasification reactor

Info

Publication number: WO2024134230A1
Application number: PCT/HU2023/050091
Authority: WO
Inventors: Károly Henger; Csaba SZILI; Márta SZLAMÁNÉ KÁKONYI; Péter Kovács
Original assignee: Henger Karoly
Priority date: 2022-12-21
Filing date: 2023-12-15
Publication date: 2024-06-27
Also published as: HUP2200495A1

Abstract

The invention is a gasification reactor that comprises an interior space (11) encompassed by a reactor wall (10) enabling a downward vertical motion, under gravity, of a material to be gasified, feed means (13) adapted for feeding the material to be gasified into the interior space (11) from above, inlet openings (20, 20', 20") adapted for introducing a gas consisting at least partly of oxygen into the interior space (11) at a first height level (H1), and a gas outlet opening formed at a second height level (H2) located under the first height level (H1). The gasification reactor according to the invention comprises inlet openings (20) configured as open lower ends of vertically oriented pipe members (21) located in the interior space (11), wherein upper ends of the pipe members (21) are in connection with one or more gas inlets adapted for introducing the gas consisting at least partly of oxygen, and wherein the pipe members (21) are provided externally, at least partially, with thermal protection.

Description

GASIFICATION REACTOR

TECHNICAL FIELD

The invention relates to a gasification reactor primarily for the recovery of a wide range of waste and biomass materials. The invention recovers the carbon, hydrogen, and oxygen content of the material to be gasified, expediently producing useful products, i.e., synthesis gas containing carbon monoxide and hydrogen, and/or - with additional purification - food-grade carbon dioxide. In addition to that, the gasification reactor according to the invention can also be applied in systems for generating electricity and/or heat.

BACKGROUND ART

Wastes and their derivatives are predominantly incinerated or are dumped in landfills. Incinerators operate utilising excess air, so in order to reach the required temperature they need a support flame that utilises fossil fuel. A challenge for gas purification is that in addition to the combustion residues of the substances (e.g. salts, metals) originally present in the waste material, substances produced during combustion may also be harmful. In waste incineration plants attempts at preventing the formation of tar are made by trying to achieve as high a combustion temperature as possible. This is, however, limited by the moisture content of the starting material and the excess air necessarily applied for the process, which contains oxygen in a diluted form. The formation of tar poses a problem not only because it has to be removed from the flue gases after the combustion process, but also because it has high energy content and is discarded as slag without utilization, thereby deteriorating the efficiency of the entire system.

An even more serious challenge than the formation of tar is that the flue gases may contain dioxins and furans, i.e., halogen-containing compounds harmful to humans that recombine at 450-500°C, so it is expedient to perform halogen removal at a temperature hotter than that.

Pyrolysis is performed under exclusion of air/oxygen, applying thermal decomposition. The necessary heat must be supplied from an external source, the end product of the process mainly having a liquid form and containing many aromatic compounds that are harmful to health. As much as 30-50% of the carbon content ends up in aromatic compounds. The gases produced during the process in a low quantity (methane and hydrogen) are utilised for maintaining the process. In contrast to that, the method described in the present document produces hydrogen, carbon monoxide, and carbon dioxide as end products, accompanied by a minimal amount of water.

Due to the above-described problems, the focus of development in the field has shifted to the gasification of waste or waste derivatives, for example RDF (refuse derived fuel) and SRF (solid recovered fuel), also producing synthesis gas (CO and H2) or hydrogen in the process. In the synthesis gas production apparatus, carbon is decomposed with water vapour (steam). A significant proportion of gasification processes are endothermic, i.e. , heat-absorbent, and their energy demand must be satisfied. The processes are illustrated in Table 1 below by the zones occurring in a downdraft reactor, listed in the table from the top to the bottom of the reactor.

Table 1 . Zones of a downdraft reactor US 2011/0289845 A1 discloses a method for gasification of solid waste materials, but the disclosed technical solution has the significant disadvantage that the combustion energy of the fed-in starting material is complemented by electric energy, applying an induction furnace in the system. A further drawback is that the document does not provide a solution for removing the solid residues, i.e. ash and slag. A very significant problem is posed by the step of the technical solution wherein air is expelled from the waste material to be fed in by mechanically compression assisted by evacuation. However, the compressed material is not gas-permeable, so this conventional solution cannot be applied in cases wherein gasification is performed without introducing external energy, in the presence of oxygen by partial oxidation.

WO 2012/084135 A1 relates to the decomposition of gaseous feedstock, for example methane. According to this document the feedstock (starting material) does not contain any oxygen, i.e., the oxygen forming the carbon monoxide of the synthesis gas comes from the water applied for reforming. The gaseous feedstock and product allow for heating the feedstock from outside in a heat exchanger. In this known technical solution, the hot flue gas applied for heating must be produced in a separate apparatus, its heat being transferred to the gas-state starting material in a conventional heat exchanger.

In US 8,070,863 B2 an extremely heat-wasting synthesis gas purification solution is disclosed that does not provide a concrete solution for efficient gasification or for efficient purification.

In WO 2009/122225 A2 a double-flow one-body synthesis gas production apparatus is disclosed that has a structural configuration that is different from the present invention and does not have the advantages provided by the invention.

WO 2019/069107 A1 proposes a technical solution for producing pure synthesis gas, wherein the gasification reactor is configured differently from the present invention. In US 4,583,992 a gasification reactor is disclosed which comprises an interior space encompassed by a reactor wall enabling the downward vertical motion, under gravity, of a material to be gasified, feed means configured for feeding the material to be gasified into the interior space from above, inlet openings adapted for introducing a gas consisting at least partly of oxygen into the interior space at a first height level, and a gas outlet opening formed at a lower level. A disadvantage of this prior art technical solution is that material flow in the reactor is not exclusively vertical because the material inside the reactor undergoes continuous mixing by a rotating platform disposed at the bottom. This makes the configuration more complicated and requires additional energy supply, which decreases the cost efficiency of the process. A further disadvantage is that the inlet openings adapted for introducing the oxygen-containing gas or the gas composed substantially of oxygen are located at various height levels, so it is not possible to form a well-defined oxidation zone having clear boundaries in the reactor space; this disadvantage makes the processes going on in the reactor less controllable. Another disadvantage of the prior art solution is that the inlet openings are implemented as the ends of pipes extending obliquely downward from a central feed channel, so they constitute an obstacle for the downward flow of the material under gravity.

DISCLOSURE OF THE INVENTION

In the course of the experiments leading to the invention it has been recognised that if the air/oxygen inlet openings are formed as the lower ends of vertically oriented pipe members, then the material flow under gravity in the reactor space is obstructed to the least possible extent, and in the case of such a configuration it is also not necessary to mix the material in the reactor space. Since the oxidation zone is formed at the height level of the inlet openings and the pyrolysis zone is located above that, in the configuration according to the invention at least partial thermal protection of the vertical pipe members must be provided. This makes it possible to select the length of the vertical-direction pipe members such that they extend at least through the pyrolysis zone formed inside the reactor space, i.e., that their upper end reaches at least the top of the pyrolysis zone. In such a way the material may proceed under gravity already along the entire height of the pyrolysis zone without being blocked by the vertical-direction pipe members, which also allows that the pyrolysis zone can be formed with controlled boundaries, and, accordingly, can facilitate the controllability of the processes going on in the reactor.

It is therefore an object of the invention to provide an apparatus having a novel configuration that is able to produce valuable gases, for example synthesis gas and hydrogen, from a material to be gasified, for example industrial waste, waste derivatives, and biomass, or the mixture thereof, and that is able to eliminate the disadvantages of prior art solutions to the greatest possible extent. It is another object to provide a configuration which ensures the formation of controlled pyrolysis, oxidation, and reduction zones, which blocks the flow of material under gravity to the least possible extent, and which can be assembled and maintained easily, while at the same time provides steady oxygen supply in the oxidation zone.

The objects according to the present invention have been achieved by the gasification reactor according to claim 1. Preferred embodiments of the invention are defined in the dependent claims.

Known solutions are not able to handle starting materials that vary greatly over time. By further developing the known waste processing and gasification solutions, we have provided a system that is able to transform various types of waste, waste derivatives, and biomass into valuable materials, i.e. , the invention is able to flexibly handle starting materials with varying elementary composition available due to different local conditions, recovering the carbon and hydrogen content of the starting material.

The configuration of the apparatus is simple, well-automatised and well-controllable, preferably being also provided with safety systems. The reactor is simple, for example tube-like, without any parts for moving the starting material; high- temperature mixing is not necessary; there is no forced forwarding, i.e., the solid materials move downward under gravity inside the reactor. The configuration of the gas inlets according to the invention does not block the movement of solid materials. Based on the measurable parameters (pressure, temperature, gas flow) that are crucial for operating the apparatus, the industrial operation of the apparatus can be controlled by appropriately designed control circuits even without human intervention.

Another significant advantage of the gasification reactor according to the invention, resulting from its configuration, is that external heat input is not necessary for its operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be explained referring to the accompanying drawings, where

Fig. 1 is a schematic view of a gasification reactor according to the invention having a cylindrical inside space,

Fig. 2 is a schematic view of a gasification reactor according to the invention with an interior space that is downward-tapering at the bottom,

Fig. 3 illustrates a preferred alternative for implementing the air/oxygen inlet openings,

Fig. 4 is a spatial drawing showing a first embodiment of the dust separator ring applicable in the gasification reactor, and

Fig. 5 is a spatial drawing of a second embodiment of the dust separator ring.

MODES FOR CARRYING OUT THE INVENTION

In the course of our experiments, we have recognised that it is preferable if the composition - primarily the C, H, and 0 content - and the water content of the starting material to be gasified is in the range included in Table 2 below. Accordingly, as a first step the starting material is expediently analysed, followed by determining the formulation that results in the ranges included in Table 2. Based on its composition, the starting material is optimised accordingly and is prepared for gasification, i.e. , if necessary, is pelletised and dried.

Table 2. Preferable concentration ranges of starting material components

The starting material of the method is a waste material or a material derived therefrom, which can be RDF, SRF, processed communal or industrial waste materials that are produced in MBS (mixed waste sorting) plants by separating their glass, metal, stone and sand content, waste biomass material (e.g. agricultural and forestry waste materials, treated wood, reeds, straw), hazardous waste materials (e.g. oil, oily rags, treated wood), industrial rubber, plastic (e.g. PE, PP, Pll, PVA, MDI, TDI, carbon- or glass fibre-reinforced plastics and composites), complemented by the required bed additive, e.g. dolomite, as well as various mixtures of the foregoing materials.

If the composition of the starting materials available in a given region is known, such a starting material mix (formulation) can be devised which can be processed utilising the gasification reactor according to the invention in a preferable manner, and thereby the hydrogen and carbon content of the starting material can be recovered. The optimal composition of the starting material can be determined utilising a software developed for the purpose, which takes into account the elemental composition, humidity, and ash content of the starting material components. In addition, for determining the ratio of starting materials the price of the starting materials can also be considered and the most economical ratio can be established bearing in mind the desired properties of the applied starting material. After mixing it to the appropriate ratio, preparing it and adjusting its humidity, the starting material is fed into the gasification reactor. The reactor is fed in an automated manner.

The gasification reactor according to the invention is a continuous-operation reactor; its interior space preferably has a tubular configuration with a constant diameter, i.e. , the pyrolysis, oxidation, and reduction zones have an identical diameter, so the solid material has a plug-like flow, preventing the formation of dead volumes and funnels. This is also aided by preferably feeding in the material without forming heaps. It therefore follows from the configuration of the reactor that in the case of a given starting material composition the positions of the zones remain constant.

The exemplary gasification reactor schematically depicted in Fig. 1 comprises an interior space 11 surrounded by a reactor wall 10 that allows the vertical motion of material to be gasified under gravity, and feed means 13 adapted for feeding the material to be gasified into the interior space 11 from above. The feed means 13 preferably include a sluice 15 and a rotated spreader means 14 adapted for feeding the material to be gasified without heaping it up. The purpose of applying the spreader means 14 is to ensure that the zones that are intended to be produced in the reactor according to the invention as well-localised, horizontally layered zones do not become distorted, but are generated in a controllable manner, as horizontal, adjustable-height zones. If the material inside the reactor is heaped up, the material flow under gravity will not be uniform across the entire flow cross-section, which causes the zones to become distorted, i.e., it results in local deviations in the height and shape of the zones from the desired horizontally layered configuration. The spreader means 14 therefore provides that the material is supplied evenly across the entire cross-sectional area.

The moving grates 16 located at the bottom of the gasification reactor are driven hydraulically. Preferably, two grate members are arranged above each other such that the bars and the interspaces are in overlap, with a moving grate 16 configured as a scraper being movable on them back and forth in a horizontal direction. Applying this configuration, it can be provided that the material particles stuck to the bottom grate member can be dislodged/removed by the upper grate member. The grate members move in an alternating manner with a timing/frequency providing that the holding time of the solid material corresponds to the given material to be gasified. The moving grates 16 are applied for controlling the fall of the material under gravity at the bottom of the gasification reactor such that a charcoal bed is produced in the reduction zone, having a height providing that the holding time therein of the generated gas is at least 2 s. Firstly, this charcoal bed aids the decomposition of tar, and it also binds tar and carbon black, thereby performing a filtering function. Secondly, it also provides a temperature maintenance function, so it is preferable to keep its thickness relatively high. The height of the charcoal bed is determined by the applied starting material and the required holding time.

The gasification reactor further comprises inlet openings 20, 20’, 20” adapted for introducing a gas consisting at least partly of oxygen into the interior space 11 at a first height level H1 . The gas consisting at least partly of oxygen can be for example air, pure oxygen or air enriched with oxygen. A gas outlet opening leading to a gas outlet line 50 is formed at a second height level H2 located lower than the first height level H1. At the height level of the gas outlet opening, a dust separator ring 30 described in detail below is disposed in the interior space 11 .

The interior space 11 of the gasification reactor is preferably kept under suction (i.e. , a slight vacuum is maintained therein), with the vacuum apparatus applied for generating the vacuum being expediently controlled to maintain a desired pressure value at the output port of the gasification reactor, i.e., at the gas outlet opening leading into the gas outlet line 50. The locations where overpressure may occur in the case of a malfunction can be identified applying risk analysis, and pressure relief valves adapted for returning in their closed state after releasing overpressure can be installed at these locations, such that air inflow cannot occur and explosions can be prevented. According to Fig. 1 , for example, the gasification reactor is preferably provided with a safety valve 17 at the top, which releases the overpressure in the case of an overpressure event, and then returns to its closed state.

The inlet openings 20, 20’, 20” arranged at the first height level H1 provide that the oxidation zone is formed in the interior space 11 as a horizontal zone having a predetermined height. The inlet openings 20, 20’ 20” are preferably located at the same height, but embodiments are also feasible in which all the inlet openings 20, 20’, 20” are located at a middle 50% height range of the desired oxidation zone, more preferably at a middle 20% height range thereof. In a preferred embodiment of the invention, a low-height oxidation zone is provided, with a height between 10 and 15 cm. By applying a relatively low-height oxidation zone, partial oxidation and uniform combustion conditions can be provided.

As can be seen in Fig. 1 and is described in more detail below in relation to Fig. 3, the gasification reactor comprises inlet openings 20 configured as the open lower ends of vertically oriented pipe members 21 located in the interior space 11 , wherein upper ends of the pipe members 21 are in connection with one or more gas inlets 25 adapted for introducing the gas consisting at least partly of oxygen, and wherein the pipe members 21 are provided externally, at least partially, with thermal protection.

The gasification reactor preferably also comprises inlet openings 20” that are formed as openings located at the first height level H1 circumferentially evenly spaced apart in the refractory masonry 12 surrounding the interior space 11 .

Due to the presence of explosive gases, ash/slag is discharged utilising a valve system that is adapted for preventing air from entering the reactor. The generated air/dust mixture is fed into a cyclone 51 via the gas outlet line 50, and the dust separated by the cyclone 51 is returned to the bottom portion of the reactor by means of a return feed screw 52; ash/slag is thus discharged at a single location. Ash/slag is removed from the bottom portion of the reactor by an ash/slag transport screw 53, in a dry state. An agitator adapted for preventing the agglomeration of ash/slag is preferably disposed at the bottom of the reactor.

Fig. 2 shows a gasification reactor that is similar to the one shown in Fig. 1 , with the difference that the interior space 11 is not cylindrical along its entire height but only at the top, its bottom portion having a downward-tapering shape. In relation to the interior space 11 , the shape of a vertical-axis body of revolution is preferable because such shape is suited for implementing the simplest, most uniform arrangement of the inlet openings 20, 20’, 20”, and furthermore, in the case of such a shape material transport under gravity can be maintained all the way through across an identical internal cross-sectional area, making it calculable and controllable. Depending on the given application, an interior space 11 arrangement having a downward-tapering shape at the bottom can be more preferable because, due to the compaction of the material in the reduction zone, such an interior space 11 may provide an even more uniform material flow under gravity, i.e. , the material is not hollowed out and is not cooled down at the bottom portion of the interior space 11.

Fig. 3 illustrates a preferred implementation variant of the air/oxygen inlet openings. The thermal protection of the pipe members 21 , 2T of the gasification reactor according to the invention preferably comprises at least one of the following: a water-cooled shell 23 (see Fig. 3), a thermal protection lining, or a refractory block lining.

In the preferred implementation according to Fig. 3, the gasification reactor comprises an arrangement of pipe members 21 wherein identical-length pipe members 21 are arranged, evenly spaced apart from one another, along a cylindrical surface that is coaxial with the vertical axis of a body of revolution, the upper ends of said pipe members being connected to a common annular manifold 22. The pipe members 21 are preferably at least partially embedded in an annular common water-cooled shell 23. In the depicted embodiment, the lower ends of the pipe members 21 protrude downward from the water-cooled shell 23, with a thermal protection lining or a refractory block lining being disposed around said lower ends. In such a manner, water-cooling can be kept above the oxidation zone, i.e., it affects only the pyrolysis zone, which involves that it will be subjected to lower heat loads.

It is preferable if the circulation lines of the water-cooling system are passed through the reactor wall 10 at the upper ends of the pipe members 21 . The gas inlets 25, 25’ leading up to the pipe members 21 , 2T can also be passed here through one or both of two support members expediently disposed in a diametrically opposing manner in the interior space 11 , the bracket members being adapted for keeping the common annular manifold 22 and the components coupled thereto suspended in the interior space 11 .

To ensure the even distribution of oxygen in the oxidation zone, the reactor preferably further comprises a central pipe member 2T that is coaxial with the vertical axis of the body of revolution and is provided externally, at least partially, with water-cooling.

Oxygen distribution can be made even more uniform by connecting a respective vertical peripheral pipe member 21 ” surrounded by the refractory masonry to each of the inlet openings 20” of the refractory masonry 12, the peripheral pipe members

21 ” being connected at their upper ends to an annular common peripheral manifold 24. The peripheral pipe members 21 ” do not necessarily require a cooling in relation to the inlet openings 20” located in the refractory masonry 12, because they are adequately protected against heat by the refractory masonry 12.

The pipe members 21 , 2T, 21 ” are expediently made of stainless steel, more preferably of heat-resistant stainless steel. In the oxidation zone, the inlet openings 20, 20’, 20” at the first height level H1 are preferably distributed along the cross section of the material flowing under gravity such that oxygen in-feed is as uniform as possible, and that no location of the cross section lies at a greater distance from the inlet openings 20, 20’, 20” than a predetermined distance limit. This predetermined distance limit can be for example 10, 15, or 20 cm. If, for example a distance limit of 10 cm is contemplated, then the distance between the central pipe member 21 ’ and the pipe members 21 configured to connect to the annular manifold

22 is 20 cm, and an identical distance can be present between the latter pipe members 21 and the refractory masonry 12 and the additional inlet openings 20” included therein.

The uniformity of oxygen feed in the oxidation zone is essentially intended to provide that the temperature does not fall below 1000 °C anywhere across the cross section of the gravitational material flow, and that preferably the temperature is in the range of 1000-1200 °C everywhere.

Such a configuration can also be conceived wherein the inlet openings 20, 20’, 20” are arranged in an annular fashion along more rings than is shown in the drawings, and therefore are able to provide oxygen supply to the material in the oxidation zone across an even greater cross section.

In a manner shown in Fig. 3, the material to be gasified flows under gravity between the inlet openings 20, 20’, 20”. This requires that at least one intermediate ring is supported by brackets in the interior space 11. This bracketed support is preferably configured such that it blocks the flow of the material as little as possible. This expediently suggests that the bracketed support is implemented by applying bracket support members, implemented in any suitable manner, that are configured integrally with the gas inlets 25 and are connected at their outside and inside ends to the reactor wall 10 of the gasification reactor and to the annular manifold 22, respectively. An identical bracket support member can be connected to the gas inlet 25’ of the central pipe member 2T. The pipe section of the gas inlet 25’ can preferably be supported at the upper rim of the water-cooled shell 23, thereby providing bracket support for the central pipe member 2T. In the solution according to Fig. 3, therefore, the reactor wall 10 only carries three bracket support members; this configuration blocks the flow of the material under gravity as little as possible. The inlets and outlets of the water-cooling circuit are expediently also located inside the bracket support members or are connected thereto. In the bracket support members, the gas inlets 25, 25’ and the inlets and outlets of the water-cooling circuit are preferably arranged under each other, such that the bracket support members have as small an area directed perpendicular to the material flow as possible.

As shown in Fig. 3, the central pipe member 2T may have greater diameter than the other pipe members 21 , 21 ”, and may even have more than one inlet openings 20’, for example by having a base cover at the bottom, with a plurality of openings being formed laterally near the bottom. The diameter of the central pipe member 2T is for example 50 mm. To provide cooling, the central pipe member 2T is provided with a sleeve; at its lower portion only refractory blocks are present without cooling.

The pipe members 21 of the central ring are encompassed by the annular water- cooled shell 23 along approximately three-fourths of their length, along the remainder they are preferably covered with refractory blocks. The diameter of the pipe members 21 is approximately 10-20 mm, and as many as 6-32 of such pipe members are included.

At the outer ring located along the reactor wall 10, the diameter of the pipe members 21 ” is approximately 10-20 mm, and for example 12-64 pipe members can be included; water cooling - utilising for example cooling water circulated in the pipe sleeve - can also be applied in relation to these pipe members.

Each air/oxygen feed means, that is, each of the feed hanging at the middle, the central ring, and the peripheral ring has its own separate air/oxygen supply, i.e. , the pre-heated supplied air is divided into 3 parts and the air supply to the three circuits is controlled by means of valves.

A dust separator ring 30, 40 depicted in Figs. 4, 5 having a height greater than the height of the gas outlet opening is preferably arranged in the interior space 11 at the second height level H2. The dust separator ring 30, 40 essentially constitutes the bottom section of the interior space 11 . The dust separator ring 30, 40 is made from evenly spaced apart, axially extending plate members 31 , 41 with plate surfaces closing at an angle with respect to the circumferential direction. In the variant that can be seen in Fig. 4, the dust separator ring 30 has a rotationally symmetric configuration and the plate members 31 are flat. In the variant that can be seen in Fig. 5, the dust separator ring 40 has a rotationally symmetric configuration, and the plate members 41 are L-profile bars, with the leg of the L-profile being preferably directed inward. As can be seen in both figures, a baffle plate 32, 42 that has a surface area greater than the cross-sectional area of the gas outlet opening and is configured to have a surface shape following the shape of the dust separator ring 30, 40 is arranged between the outside surface of the dust separator ring 30, 40 and the gas outlet opening, the baffle plate being preferably welded to the plate members 31 , 41.

A slight vacuum (preferably of 110-30 mbar) is maintained inside the reactor, so the dust separator ring 30, 40 is also under suction, the gas being sucked out from the gaps between the plate members 31 , 41 of the dust separator ring 30, 40. The plate members 31 , 41 are uniformly directed obliquely with respect to the circumferential direction, thereby baffling and mixing the gas and giving it an angular momentum, as a result of which a part of the dust and ash particles in the gas is caught by the plate members 31 , 41 and falls back down. Flowing between the plate members 31 , 41 and into the gas outlet port (opening) located at one of the reactor’s sides, the gas leaves the reactor.

The material to be gasified is therefore fed to the reactor through the sluice 15. Inside the reactor, the material proceeds downward under gravity. The inside of the apparatus is lined or bricked with preferably more than one layers of refractory blocks, or is provided with other conventional thermal insulation, at least downward from the pyrolysis zone. The applied thermal insulation and the partial combustion (partial oxidation) of the material to be gasified provides that it is not required to introduce external heat into the system in order to meet the heat demand of endothermic processes, i.e., neither heat input nor heat extraction is required. Preferably, the infeed of the material is controlled by a level sensor installed at the top of the interior space 11 . Air and/or oxygen infeed is performed along the entire cross section of the reactor in an evenly distributed fashion, such that it restricts the free flow of the solid fraction by the least possible extent. The air/oxygen feed pipes are preferably arranged along concentric circles. Feed pipes are preferably cooled, and their dimensions are expediently chosen according to the reactor’s cross section and also to ensure appropriate combustion. Air distribution between the air/oxygen rings is controlled by means of valves. The ratio of air and oxygen is set in accordance with the starting material. In the case of a material to be gasified with high carbon content it is also possible to introduce steam into the reactor. The gas generated as a result of the process is preferably conveyed to a purifier system. The gas, for instance synthesis gas generated in the gasification reactor is preferably kept at a high temperature until the halogen content of the gas is removed. The tar content of the produced gas is removed preferably in a washing apparatus applying a wet, oily medium, and then the gas is purified of its dust and sulphur content.

It has been verified by experiments that the gasification reactor according to the invention is suited for utilising a wide variety of starting materials, and it can be operated simply and flexibly thanks to its well-thought-out controllability and the adjustability of the zones. The configuration according to the invention ensures that the gas leaving the reactor has high temperature, which is necessary for purifying the gas of halogens.

The invention is, of course, not limited to the embodiments also depicted in detail in the figures, but further variants and modifications are possible within the scope of protection determined by the claims. The interior space 11 may have a shape other than a body of revolution, and the inlet openings may have other arrangements than the annular one. The thermal protection of the pipe members can of course be provided by other means than that detailed hereinabove.

Claims

1 . A gasification reactor comprising an interior space (11 ) encompassed by a reactor wall (10) enabling a downward vertical motion, under gravity, of a material to be gasified, feed means (13) adapted for feeding the material to be gasified into the interior space (11 ) from above, inlet openings (20, 20’, 20”) adapted for introducing a gas consisting at least partly of oxygen into the interior space (11 ) at a first height level (H1 ), and a gas outlet opening formed at a second height level (H2) located under the first height level (H1 ), characterised by comprising inlet openings (20) configured as open lower ends of vertically oriented pipe members (21 ) located in the interior space (11 ), wherein upper ends of the pipe members (21 ) are in connection with one or more gas inlets (25) adapted for introducing the gas consisting at least partly of oxygen, and wherein the pipe members (21 ) are provided externally, at least partially, with thermal protection.

2. The gasification reactor according to claim 1 , characterised in that the thermal protection comprises at least one of a water-cooled shell (23), a thermal protection lining, and a refractory block lining.

3. The gasification reactor according to claim 2, characterised in that the interior space (11 ) has the shape of a vertical-axis body of revolution.

4. The gasification reactor according to claim 3, characterised by comprising an arrangement of pipe members (21 ) wherein identical-length pipe members (21 ) are arranged, evenly spaced apart from one another, along a cylindrical surface that is coaxial with the vertical axis of the body of revolution, the upper ends of said pipe members being connected to a common annular manifold (22).

5. The gasification reactor according to claim 4, characterised in that the pipe members (21 ) are at least partially embedded in an annular common water-cooled shell (23).

6. The gasification reactor according to claim 5, characterised in that lower ends of the pipe members (21 ) protrude downwardly from the water-cooled shell (23), wherein a thermal protection lining or a refractory block lining is disposed around these lower ends.

7. The gasification reactor according to claims 5 or 6, characterised in that circulation lines of the water-cooling are passed through the reactor wall (10) at the upper ends of the pipe members (21 ).

8. The gasification reactor according to any of claims 5-7, characterised by further comprising a central pipe member (2T) that is coaxial with the vertical axis of the body of revolution and is provided externally at least partially with water-cooling, wherein one or more inlet openings (20’) are formed at a bottom of said central pipe member.

9. The gasification reactor according any of claims 4-8, characterised by also comprising inlet openings (20”) that are formed as openings located at the first height level (H1 ) circumferentially evenly spaced apart in the refractory masonry (12) surrounding the interior space (11 ).

10. The gasification reactor according to claim 9, characterised in that a respective vertical peripheral pipe member (21 ”) encompassed by the refractory masonry (12) is connected to each inlet opening (20”) located in the refractory masonry, wherein the peripheral pipe members (21 ”) are connected at their upper ends to a common peripheral manifold (24).

11. The gasification reactor according to claim 3, characterised in that a dust separator ring (30, 40) having a height greater than the height of the gas outlet opening is arranged in the interior space (11 ) at the second height level (H2), the dust separator ring (30, 40) being formed with axial-direction plate members (31 , 41 ), the plate surfaces of which being oriented at an angle with respect to the circumferential direction.

12. The gasification reactor according to claim 11 , characterised in that the dust separator ring (30) has a rotationally symmetrical configuration, and the plate members (31 ) have a flat shape.

13. The gasification reactor according to claim 11 , characterised in that the dust separator ring (40) has a rotationally symmetrical configuration, and the plate members (41 ) are L-profile bars.

14. The gasification reactor according to any of claims 11 -13, characterised in that a baffle plate (32, 42) having a surface area greater than the cross-sectional area of the gas outlet opening and being configured to have a surface shape following the shape of the dust separator ring (30, 40) is arranged between the outside surface of the dust separator ring (30, 40) and the gas outlet opening.

15. The gasification reactor according to claim 14, characterised in that the baffle plate (32, 42) is welded onto the plate members (31 , 41 ) of the dust separator ring.

16. The gasification reactor according to claim 1 , characterised in that the feed means (13) comprise a rotating spreader means (14) facilitating a heap-avoiding feeding of the material to be gasified.

17. The gasification reactor according to claim 3, characterised in that the interior space (11 ) has a cylindrical shape, or a shape that is cylindrical at the top and downward-tapering at the bottom.