DEVICE FOR THE UTILIZATION OF PROCESS GAS BY CONVERTING WASTE MATERIALS AND FORMING SYNTHETIC GAS

Description

[0001] The present invention relates to a device for utilizing process gas by converting waste materials and producing synthesis gas, as well as a corresponding method. In particular, the present invention aims at maximizing H2 recovery (hydrogen gas recovery) during the production of synthesis gas.

[0002] Chemically contaminated solid particles such as dust, dry sludge, and sludge from the chemical industry, metallurgy, agriculture, municipal and industrial waste disposal, etc., and in particular combustion dust, grinding dust, steel mill dust, sewage sludge, animal meal, shredder light fraction, waste wood, battery scrap, waste plastic, waste solvents, and the like, pose a major environmental problem due to their high inorganic and organic pollutant content, as well as their large specific surface area and high chemical reaction potential with the environment. The processing of these small solid particles is the subject of a wide variety of technologies.For this purpose, the applicant of the present invention has recently proposed a device in Austrian patent application A 277 / 2020, which has a housing and, in the housing, a combustion chamber lined with refractory material, wherein an axial inlet opening into the housing is provided at a first axial end of the housing, to which a feed device having a storage space for the solid particles is connected with a discharge opening for the solid particles, wherein a lance for injecting gases and / or aerosols into the combustion chamber axially penetrates the inlet opening and is immersed axially into the combustion chamber, and wherein the lance is separated from the storage space by a casing, wherein the casing extends into the combustion chamber and over the region of the lance immersed in the combustion chamber.When operating this device according to the process also proposed in this application, gaseous and / or solid reaction products are removed, and solid reaction products are separated from gaseous reaction products in a cyclone separator. Furthermore, it is provided that the process gas is brought into contact with wood for cooling and reacted, and the resulting charcoal and / or wood ash particles laden with adhering reaction products are fed to non-ferrous metallurgical processing.

[0003] The process gas to be utilized or converted according to the present invention is produced in the contemplated processes and devices at a temperature of approximately 1600°C to 1800°C and consists essentially of CO2 and H2O and optionally contains sulfur and traces of heavy metals, for example zinc, copper, cadmium, iron, etc., as well as their compounds. Furthermore, alkalis, alkaline earths, halogens and sulfur dioxide can be present in the process gas. The contemplated devices and processes in which the process gas is produced, to which reference is made in the present application, are further disclosed in particular in the applications WO 2018 / 122599 A1 and WO 03 / 070651 A1. An analogous process gas is also produced when biogas is burned with O2.

[0004] The present invention takes on the task of consistently processing process gas, as it is formed, for example, in the devices and methods described and mentioned above, both in order to use the considerable heat content and material content of the process gas in the form of CO 2 and H 2 O in an ecologically and economically sensible manner, and in order to form synthesis gas consisting essentially of H 2 and CO by recycling and disposing of waste materials, such as wood chips, biomass, waste fractions, waste plastics, waste solvents, shredder light fraction, waste wood and the like, whereby chemically usable hydrogen gas (H 2 ) and CO 2 can subsequently be obtained.

[0005] The patents EP 0 139 092 A1 and US 4 400 181 A disclose processes for gasifying coal using reactors with specific feeding mechanisms.

[0006] To achieve this object, a device for utilizing process gas by converting waste materials and forming synthesis gas according to claim 1 is proposed.

[0007] The device according to the invention thus allows waste materials to be converted or recycled, in particular wood chips, biomass, waste fractions, waste plastics, shredder light fraction, waste wood, and the like, to be heated by flowing hot process gas around them, whereby pyrolysis and, depending on the intensity of the heating, partial gasification of the waste materials takes place in the at least one conveyor pipe. The defined length of the at least one conveyor pipe is between 40 cm and 200 cm, depending on the specific design described below. As a result of the pyrolysis and, if appropriate, partial gasification, gases are formed from the waste materials in the conveyor pipe. These gases cause the waste materials introduced by the feed device to be loosened and explosively propelled out of the conveyor pipe and into the riser pipe.The waste materials shredded in this way end up in chunks and with a relatively large surface area in the gas stream of the process gas in the riser pipe, which flows around at least one conveyor pipe from below at high speed and continues to flow upwards in the riser pipe, entraining the shredded waste materials. As a result of this and the large amounts of heat provided by the process gas, the waste materials are completely pyrolyzed and gasified or converted, and the process gas is cooled in the process. The gasification of the waste materials to form synthesis gas consisting essentially of CO and H2 can, in principle and depending on the composition of the waste materials, provide sufficient heat for the endothermic conversion of the process gas consisting essentially of CO2 and H2O to form synthesis gas from CO and H2.In this way, hydrogen and carbon monoxide (water gas, also known as synthesis gas) are formed from exhaust gas (process gas) and waste materials, which allows waste materials to be disposed of profitably and, at the same time, the waste heat from a wide variety of combustion processes to be used.

[0008] In order to ensure particularly efficient heat transfer in the feed device, the feed device is preferably formed by a plurality of conveyor pipes projecting radially or tangentially into the riser pipe, wherein the conveyor pipes are preferably directed obliquely upwards with respect to the axial direction. According to this preferred embodiment, a plurality of conveyor pipes is thus provided as the feed device, so that for a certain throughput of waste materials, smaller quantities of the waste materials are located in each individual conveyor pipe of the feed device. This leads to faster and more intensive heating and thus to very efficient pyrolysis and, if appropriate, partial gasification. The preferred orientation of the conveyor pipes obliquely upwards ensures that the pyrolyzed waste materials are introduced into the riser pipe in a manner that is advantageous with respect to the flow direction of the process gas in the riser pipe.In this preferred embodiment, the defined length of the conveyor pipes is between 40 cm and 120 cm.

[0009] According to a preferred, alternative embodiment of the present invention, the feed device is formed by a conveyor pipe extending axially, in particular concentrically, into the riser pipe at a lower end of the riser pipe. This embodiment is advantageous in terms of its space-saving design without conveyor pipes opening into the riser pipe from the side and in terms of the flow-optimized introduction of the pyrolyzed waste materials into the riser pipe. Furthermore, for a certain riser pipe diameter, the defined length over which the conveyor pipe extends into the riser pipe can be longer than with the previously described radial or tangential configuration of the conveyor pipes, so that a very effective heat transfer to the waste materials in the conveyor pipe again occurs. The defined length of the conveyor pipes in this preferred embodiment is between 40 cm and 200 cm.In this embodiment, the conveyor pipe points with its open end directly in the direction of the axis of the riser pipe, so that the pyrolyzed waste materials ejected from the conveyor pipe are thrown in the flow direction of the process gas stream.

[0010] According to the present invention, the conveying of the waste materials through the at least one conveying pipe is achieved in terms of apparatus in that the at least one conveying pipe has a conveying device in the form of a conveyor screw arranged in the conveying pipe, a piston slide and / or a thick-flow pump at an end facing away from the open end. The type of conveying device can be selected depending on the type of starting materials, wherein it can preferably also be provided that the conveying device is removably attached to the end facing away from the open end, whereby the conveying device can be removed and replaced if the waste materials to be recycled change.

[0011] A preferred embodiment of the present invention provides that the at least one conveyor pipe has a widened portion toward the open end, wherein the widened portion is preferably conical or curved. This is considered advantageous with regard to the completeness of the pyrolysis. Furthermore, in this variant of the present invention, particularly small-particle waste fractions are preferably entrained from the funnel-shaped widened portion by the gas stream of the process gas, thus again providing a large surface area for the gasification reactions in the riser pipe.

[0012] Preferably, the at least one conveyor pipe has fins extending radially into the interior of the conveyor pipe. This preferred measure serves to improve the transfer of the heat introduced into the riser pipe by the process gas to the waste materials in the at least one conveyor pipe, since the fins are suitable for conducting heat from the surface of the conveyor pipe into the interior of the conveyor pipe in order to efficiently heat waste material regions located inside the conveyor pipe.

[0013] For better heat transfer in the at least one conveyor pipe and for the pyrolysis processes in the at least one conveyor pipe, the present invention is preferably further developed in such a way that the at least one conveyor pipe has an axially mounted rotor. If lamellae extending radially into the interior of the conveyor pipe are additionally present, the rotor can be arranged within lamellae extending radially into the interior of the conveyor pipe or in an axial region of the conveyor pipe below or above the region of the lamellae extending radially into the interior of the conveyor pipe. The rotor mixes the waste materials in the conveyor pipe and in doing so also causes the waste materials to be shredded, thus counteracting the formation of caking inside the conveyor pipe.

[0014] According to a preferred embodiment of the present invention, the at least one conveyor pipe has a fire-resistant casing, whereby the service life of the at least one conveyor pipe in the process gas stream, which is initially around 1700°C hot, within the riser pipe is significantly increased.

[0015] Depending on the type of waste materials, it may be necessary to provide additional oxygen for the gasification of the waste materials to form synthesis gas from CO and H 2 and for the simultaneous endothermic conversion of the process gas consisting essentially of CO 2 and H 2 O to form synthesis gas from CO and H 2. In this context, the present invention is preferably further developed in such a way that the at least one conveyor pipe is designed to introduce oxygen and / or H 2 O into the riser pipe. The oxygen can be provided in the form of ambient air or, preferably, as largely pure oxygen gas of technical origin. A considerable increase in the H 2 yield is achieved in the device according to the invention if, alternatively or additionally, a supply line for oxygen and / or H 2 O which is different from the at least one conveyor pipe opens into the riser pipe, so that oxygen and in particular H 2 O can be introduced as vapor.The presence of H 2 O promotes an exothermic water-gas shift reaction at temperatures below 300°C, in which CO and H 2 O are converted to CO 2 and H 2 (CO + H 2 O -> CO 2 + H 2 ). Thus, simply adding steam yields significantly larger quantities of valuable hydrogen gas (H 2 ), which can then be used thermally or, preferably, in the chemical industry, metallurgy, or for energy generation in fuel cells.

[0016] In this context, it may be considered preferable if the at least one conveying pipe has a plurality of tubes along its circumference, opening out at the open end of the conveying pipe and designed to convey water and / or steam to the open end. This not only enables the additional introduction of H2O just explained, but also provides effective cooling of the conveying pipe by water conveyed and evaporating in the tubes. The water evaporating in the tubes can escape abruptly at the open end due to the increase in volume occurring during evaporation, thus ensuring additional disintegration of the waste materials introduced into the riser pipe. The tubes are arranged on the circumference of the conveying pipe and can preferably be attached to the outside of the at least one conveying pipe, or incorporated into the wall of the at least one conveying pipe, or partially form the wall.

[0017] A further preferred embodiment of the present invention provides that the at least one conveying pipe in the riser is concentrically surrounded by an external steam line. This also allows water to be introduced into the riser while simultaneously protecting the conveying pipe from excessive heat in the riser. Furthermore, a controlled steam flow can effectively atomize, for example, liquefied waste plastics.

[0018] Furthermore, according to a preferred embodiment of the present invention, it can be provided that an inner steam line is arranged concentrically in the at least one conveyor pipe, wherein the inner steam line and the conveyor pipe converge outside the riser pipe and the conveyor pipe enters the riser pipe projecting above the inner steam line. In this way, for example, liquefied waste plastic is atomized while still in the conveyor pipe and can thus be converted with a large specific surface area. With a device designed in this way according to the present invention, plastics with a high chlorine content in particular can be subjected to pyrohydrolysis and gasification to H 2 and CO extremely quickly. The hydrochloric acid (HCl) produced in this process can be neutralized by adding lime additive (CaO, Ca(OH) 2 ).

[0019] The device according to the invention is particularly suitable for the disposal of waste plastics and is therefore preferably further developed in such a way that the conveyor pipe is connected to a melting container for plastics via a feed line, wherein the melting container is preferably pressurized with an inert gas, in particular nitrogen. Steelworks dust can preferably be added to waste plastics before it enters the conveyor pipe, since this dust, in addition to excellent catalytic properties with regard to the gasification of the waste materials and their conversion in the water gas shift reaction, in particular due to the presence of Zn and Fe in the dust, also has desulfurization properties through the formation of metal sulfides such as ZnS or FeS 2 from H 2 S. The concentration of H 2 S in the exhaust gas can be reduced to below 50 ppm in this way.

[0020] Since the water gas shift reaction is exothermic, it can be provided that a cooling device is arranged inside the riser tube in order to cool the gas in the riser tube, wherein the cooling device is preferably made of an alloy of iron, cobalt, molybdenum and / or chromium, as corresponds to a preferred embodiment of the present invention. The cooling device is arranged in a region of the riser tube above the feed device. In this region of the cooling device, synthesis gas is either already present at temperatures below 700°C, above which temperature the water gas shift reaction can take place in order to increase the yield of H2 from the synthesis gas, or the cooling device is suitable for lowering the temperature accordingly. Cooling preferably takes place to a gas temperature of initially approximately 700°C to 380°C at the end of the gas flow path through the cooling device in the riser tube.In this way, gas conversion is achieved at a relatively high temperature level in the riser tube. The design of the cooling device, made of iron, cobalt, molybdenum, and / or chromium, ensures heterogeneous catalysis of the water gas shift reaction.

[0021] Alternatively or additionally, depending on the process conditions, a heating device may be arranged inside the riser pipe to heat the gas in the riser pipe. The heating device is preferably made of an alloy of iron, cobalt, molybdenum, and / or chromium. This can be useful if significant amounts of refractory carbon (soot) are formed in the gasification gas in the riser pipe. This refractory carbon can be reactivated and broken down by the heating device. If the refractory carbon is not activated as described, it can be removed from the process and used, for example, in tire production as so-called "carbon black."

[0022] For the elimination of solid components from the gas stream formed in the device according to the invention, the invention is preferably further developed in such a way that the exhaust gas treatment system comprises a gas cyclone and / or a bag filter, and preferably a recirculation device for fine dust, in particular heavy metal fine dust, flows from the gas cyclone and / or the bag filter into the riser pipe. Alternatively or additionally, deep-bed filters, ceramic filters, or electrostatic precipitators can also be used.It is particularly advantageous that the filtered-out particulate matter, comprising heavy metal fractions of zinc, copper, cadmium, iron, and the like, has grain sizes of less than 20 µm, with approximately 98% of the particulate matter having grain sizes of less than 5 µm, exhibits excellent catalytic properties for the water gas shift reaction when returned to the riser pipe in the area of ​​the cooling device or just below it. To ensure the catalytic properties of the heavy metal particulate matter, any excess of halogen and sulfur compounds can be captured by adding alkalis or alkaline earths, which can either be added to the waste materials or introduced via a separate feed line, for example via the feed line for injecting oxygen and / or H2O, which is different from the at least one conveying pipe.

[0023] In order to further increase the H2 yield of the gas obtained in the device through the water gas shift reaction and to simultaneously reduce the CO content, it is preferred that a converter tube, preferably coaxially connected to the riser tube, is arranged between the riser tube and the exhaust gas treatment system and has a larger diameter than the riser tube. The converter tube is preferably made of an alloy of iron, cobalt, molybdenum and / or chromium. The converter tube is thus characterized by an larger diameter than the riser tube, whereby the flow velocity of the gas in the converter tube is reduced and the residence time of the gas in the converter tube is consequently increased. The walls of the converter tube can preferably be formed from the aforementioned catalytically active alloys, as already explained above in connection with the cooling device.In the converter tube, the gas temperature is further reduced from an initial approximately 380°C to approximately 200°C, which drives the water-gas shift reaction at a low temperature level and further increases the H2 yield. For this purpose, a corresponding cooling device is arranged in the converter tube. An isothermal fluidized bed is formed in the converter tube by filling the converter tube with steelworks dust, which can be kept suspended by the gas stream. Refractory carbon may also be reactivated in the fluidized bed due to the increased residence time. Preferably, a deep-bed filter filled with a ceramic mass can be used instead of the fluidized bed.

[0024] To reliably prevent steel mill dust from descending into the riser pipe, the present invention can preferably be further developed in such a way that a gas-permeable base, preferably in the form of a wire mesh, a cross-grating, a perforated plate, a grate, or a ceramic deep-bed filter, is arranged between the riser pipe and the converter pipe. These preferred internals support the fluidized bed against downward sinking, and larger quantities of steel mill dust can be introduced into the converter pipe to build up a loose layer of steel mill dust.

[0025] Due to the presence of steel mill dust in the converter tube, catalytic processes result in an almost complete elimination of CO in the exhaust gas, so that only CO 2 and large amounts of H 2 are retained in the exhaust gas.

[0026] As already described in connection with the high-temperature water gas shift reaction in the region of the cooling device in the riser tube, the catalysis of the water gas shift reaction can also be further optimized in the region of the converter tube if a recirculation device for fine dust, in particular heavy metal fine dust, flows from the gas cyclone and / or the bag filter into the converter tube, as corresponds to a preferred embodiment of the present invention.

[0027] The method according to the invention for utilizing process gas by converting waste materials, in particular wood chips, biomass, waste fractions, waste plastics, waste solvents, shredder light fraction, waste wood and the like, and by forming synthesis gas takes place according to the features of claim 14.

[0028] The conversion of waste materials, in particular wood chips, biomass, waste fractions, waste plastics, shredder light fraction, waste wood and the like to form synthesis gas takes place in the process according to the invention preferably at process gas temperatures of 1800°C to 700°C, preferably 1700°C to 700°C, more preferably at 1600°C to 700°C. These temperature levels of the process gas arise from a combustion process preceding the process according to the invention and provide sufficient heat and also reactants (CO 2 and H 2 O) for the pyrolysis and optionally partial gasification of the waste materials, as described above. The process gas of the preceding combustion process consists essentially of CO 2 and H 2 O and the pyrolysis and gasification of the above-mentioned waste materials results in synthesis gas (also known as water gas) consisting essentially of CO and H 2 from the process gas and the pyrolysis and gasification products of the waste materials.

[0029] The process according to the invention is preferably carried out in such a way that the synthesis gas is converted in the sense of a water-gas shift reaction in the riser tube with cooling, preferably at temperatures of initially 700°C to 380°C at the end, and / or in a converter tube, preferably coaxially connected to the riser tube, with a larger diameter than the riser tube, at temperatures of initially 380°C to 200°C at the end, wherein the converter tube preferably consists of an alloy of iron, cobalt, molybdenum, and / or chromium. The fundamental inventive considerations regarding the inventive features of the process with regard to the converter tube with an enlarged diameter and with regard to the heterogeneous catalysis by the aforementioned alloys and / or steelworks dusts (these dusts arise during the LD refining process and in the electric arc furnace for steel production) have already been explained in connection with the description of the device according to the invention.At the end of the gas conversion process, CO2 contained in the gas can be removed, for example, by membrane processes, alkaline scrubbing, or even by PSA (pressure swing adsorption) processes, yielding almost pure hydrogen gas. In particular, pressure swing adsorption can achieve purities of up to 99.999% of the hydrogen gas obtained.

[0030] Based on the considerations already mentioned above regarding the initiation of a water gas shift reaction for the increased formation of hydrogen (H 2 ), according to a preferred embodiment of the present invention, water and / or steam can be supplied to the riser tube.

[0031] According to the present invention, steelworks dusts are added to the waste materials, particularly in the case of waste plastics, before they enter the conveyor pipe. In addition to excellent catalytic properties with regard to the gasification of the waste materials and their conversion in the water gas shift reaction, particularly due to the presence of Zn, Co and Fe in the dusts, steelworks dusts also have desulfurization properties through the formation of metal sulfides (ZnS, FeS 2 ) from H 2 S. The concentration of H 2 S in the exhaust gas can be reduced to below 50 ppm in this way. The cations in the steelworks dusts are reduced by H 2 and CO in the water gas. After their reduction, the steelworks dusts are preferably oxidized by adding steam to form H 2 .This means that the reduced dusts are regenerated by adding water, preferably in a fluidized bed at 400°C to 900°C, forming, in particular, the catalytically active species FeO and ZnO, which can then be used for catalysis. The added water is reduced to hydrogen. Thus, the regeneration of the catalysts in turn contributes to an increased hydrogen yield in the process according to the invention.

[0032] If insufficient amounts of waste materials are added to the process according to the invention, CO 2 can still be measured in the synthesis gas of the process according to the invention after the above-described conversion of the waste materials by the process gas. The process according to the invention is therefore preferably further developed in such a way that CO 2 is measured in the synthesis gas and the addition of waste materials is increased if the CO 2 content in the synthesis gas is greater than 2 vol.%.

[0033] The conversion of the synthesis gas in the converter tube preferably takes place in a fluidized bed of steel mill dust and / or in a ceramic deep-bed filter.

[0034] For the elimination of solid components from the flow of synthesis gas formed in the device according to the invention, the method according to the invention is preferably further developed in such a way that solid components are separated by means of a gas cyclone and / or bag filter connected to the riser pipe or the converter pipe.

[0035] According to a preferred embodiment of the present invention, particulate matter, particularly heavy metal particulate matter, consisting essentially of heavy metal fractions of zinc, copper, cadmium, cobalt, iron, and the like with grain sizes smaller than 20 µm, with approximately 98% of the particulate matter having grain sizes smaller than 5 µm, is recycled from the gas cyclone and / or the bag filter to the riser and / or the converter tube. This heavy metal particulate matter exhibits excellent catalytic properties for the water-gas shift reaction. For the same reasons, it is also considered advantageous to feed LD (Linz-Donawitz) converter dust, electric furnace dust, and / or steelworks dust to the riser due to the high proportion of Zn, Cu, Cr, Mo, Fe, Co, Mo, and the like, which are present primarily in oxidic form and in very fine-grained form.Furthermore, dusts from waste incineration, which are mainly present in chloride form, shredder light fraction due to the high silicate content and aluminum content and especially due to the highly active subgroup elements, as well as cable scrap and / or electronic scrap can advantageously be fed to the process according to the invention.

[0036] To ensure the catalytic properties of the heavy metal particulate matter, any excess of halogen and sulfur compounds can be captured by supplying alkalis and / or alkaline earths to the riser pipe and / or the converter pipe, for example, via the at least one conveying pipe. This corresponds to a preferred embodiment of the present invention.

[0037] The target gas to be obtained with the device or method according to the invention consists essentially of H 2 , CO 2 , and H 2 O at a temperature of approximately 250°C. After cooling to approximately 40°C, a condensate precipitates corresponding to the dew point of the target gas (dew point of water). The CO 2 is generally removed from the remaining gas containing H 2 and CO 2 by amine scrubbing (for example, with monoethanolamine) or by cryogenic condensation or PSA processes. In this way, H 2 can be obtained with a purity of approximately 98% and up to 99.999%. Thermal regeneration of the (monoethanol)amine produces highly concentrated CO 2 , which can be used, for example, as an inert gas. The regenerated amine can be recycled back into the process for amine scrubbing.

[0038] The invention will be explained in more detail below with reference to an embodiment shown in the drawing. Figure 1 a schematic representation of a device according to the invention, Figure 2 a schematic representation of the arrangement of conveyor pipes of a feed device not according to the invention, Figure 3 a schematic representation of an inventive arrangement of a conveyor pipe of the feed device, the Figures 4a and 4b Sectional views of conveyor pipes of the feed device of a device according to the invention, Figure 5 a schematic representation of a converter tube for low-temperature gas conversion, Figure 6 another sectional view of a conveyor pipe of the feed device and Figure 7 a schematic representation of a feeding device not according to the invention.

[0039] In Figure 1The device according to the invention is designated by the reference numeral 1. The device 1 comprises a vertically arranged riser pipe 3 formed along an axial direction or flow direction 2. The axial extent is also symbolized by the longitudinal axis designated by the reference numeral 4. 5 designates a feed line for the process gas, which opens into the riser pipe 3. An exhaust gas treatment system 6 for gas formed in the riser pipe 3 is connected to the riser pipe 3. The waste materials are fed to the device 1 via a feed device 7. A cooling device 8 for cooling the synthesis gas is arranged in the upper region of the riser pipe 3. The cooling device 8 enables high-temperature gas conversion in the form of a water-gas shift reaction of the synthesis gas in the riser pipe 3 at temperatures ranging from an initial 700°C to 380°C at the end of the effective range of the cooling device 8.Alternatively or in addition to the cooling device 8, a heating device of the same type as the cooling device 8 can be provided for reactivating refractory carbon. It is also conceivable for the cooling device 8 to be operated as a heating device if required. Further along the flow direction 2, an outlet 9 is provided, followed by the exhaust gas treatment system 6 for gas formed in the riser pipe 3. The exhaust gas treatment system 6 comprises, in the embodiment shown in . Figure 1In the embodiment described, a cyclone separator 11 and a bag filter 12. Solid components from the gas stream at the cyclone separator 11 and the bag filter 12 can be discharged from the rotary valves 13 and 14 both from the cyclone separator 11 and from the bag filter 12, and, particularly in the case of heavy metal particulate matter, can be returned from the bag filter 12 via a corresponding return line 10 to the riser pipe 3 for catalysis of the water gas shift reaction. The purified gas, which has been subjected to the water gas shift reaction to increase the H2 yield, is withdrawn from the induced draft fan 15 and can subsequently be fed for thermal utilization or, preferably, to the chemical industry, for utilization in fuel cells, or metallurgy.

[0040] In Figure 2and the other figures, identical parts are designated by identical reference numerals, and it can be seen that conveyor pipes 16 extend radially or tangentially over a defined length into the riser pipe 3. The hot process gas stream flows around the conveyor pipes 16, and waste materials contained therein are heated accordingly and subsequently pyrolyzed. At positions 17, the conveyor pipes 16 have open ends opening into the riser pipe 3, from which ends the waste materials introduced through the conveyor pipes 16 are explosively thrown into the riser pipe 3 due to the pyrolysis processes. Reference numeral 18 designates a feed line for oxygen and / or H2O and / or O2 into the riser pipe 3, which is different from the conveyor pipes 16. In principle, CO2 or H2O can also be introduced depending on the stoichiometric requirements.The stoichiometric requirements are determined by means of a sensor device 19, and the supply of oxygen and / or H 2 O and, if appropriate, CO 2 is regulated in a control unit 20. A further sensor device is designated further up in the riser pipe 3 with the same reference numerals. In the upper part of the device 1 according to the invention, a gas converter 21 is schematically shown, to which steam is supplied in order to promote an exothermic water-gas shift reaction in which CO and H 2 O are converted into CO 2 and H 2 . The gas converter 21 is shown in . Figure 2 shown as a block diagram, the gas converter 21 is, however, either a cooling device 8 in the riser pipe 3 and / or, as explained below in connection with the explanations of Figure 5 designed as a converter tube with an enlarged diameter.

[0041] In Figure 3The conveyor pipe 16 extends over the defined length L into the riser pipe 3 and has an open end 17 opening into the riser pipe 3. The waste materials are conveyed through the conveyor pipe 16 via the feed device 7 by means of a conveyor screw 22, wherein the conveyor screw 22 is arranged at an end 23 of the conveyor pipe 16 facing away from the open end 17. Because the feed line 5 opens into the riser pipe 3 in the axial direction below the conveyor pipe 16 or below its open end 17, the process gas flowing through the feed line 5 flows around the conveyor pipe 16 and is thereby heated. As a result, pyrolysis of the waste materials occurs in the conveyor pipe 16 and, if necessary, partial gasification of the waste materials, so that the pyrolyzed waste materials are thrown into the riser pipe 3 at the open end 17 of the conveyor pipe 16 and entrained by the process gas flow.

[0042] Figure 4ashows a conveyor pipe 16 with a fireproof casing 24, wherein a rotor 26 for mixing the waste materials is arranged next to lamellae 25 extending radially into the interior of the conveyor pipe 16.

[0043] In Figure 4b a conveyor pipe 16 with a fireproof casing 24 is shown, wherein the conveyor pipe 16 has fins 25 extending radially into the interior of the conveyor pipe 16 in order to conduct the heat of the process gas acting on the conveyor pipe 16 from the outside to the waste materials located in the interior.

[0044] In Figure 5It can be seen that a converter tube 27 with a larger diameter than the riser tube 3 is arranged coaxially to the riser tube 3, wherein the converter tube 27 can be made of an alloy of iron, cobalt, molybdenum and / or chromium. In the converter tube 27 there is an isothermal fluidized bed 28 of steelworks dust which is kept in suspension by the gas flow. Between the riser tube 3 and the converter tube 27 there is a gas-permeable base 29, here in the form of a cross grid 29, which prevents the steelworks dust from settling. If the converter tube 27 is sufficiently filled, a loose layer of steelworks dust can also form, which is no longer kept in suspension but rests on the cross grid 29 and is flowed through and swirled by the gas flow.The arrows in riser tubes 3 and 27 indicate that the increased diameter in converter tube 27 compared to riser tube 3 results in a more uniform gas flow velocity. At the same time, the increased diameter leads to a decrease in flow velocity and thus to an increased gas residence time in converter tube 27.

[0045] In Figure 6 1 shows a conveyor pipe 16 which does not require a fireproof casing. To protect the conveyor pipe 16 from the hot process gas, a plurality of tubes 30 are arranged around its circumference, which open out at the open end 17 of the conveyor pipe 16 and are designed to convey water and / or steam to the open end 17. Due to the heat of the process gas, water in the tubes 30 evaporates, thereby cooling the conveyor pipe 16. As already explained in connection with the Figures 4a and 4bexplained, the conveyor pipe 16 is also Figure 6 Lamellas 25 are provided, which extend radially into the interior of the conveyor pipe 16. The tubes 30 form in the example of the Figure 6 the wall of the conveyor pipe 16.

[0046] In Figure 7It can be seen that the conveyor pipe 16 in the riser pipe is concentrically surrounded by an outer pipe 31, which represents an outer steam line 31 arranged concentrically to the conveyor pipe 16. Furthermore, a further pipe 32 is arranged concentrically to the conveyor pipe inside the conveyor pipe, but outside the riser pipe 3. This pipe 32 forms a steam line 32 arranged concentrically in the conveyor pipe 16. The steam line 32 and the conveyor pipe 16 converge, and the conveyor pipe 16 enters the riser pipe 3 projecting beyond the inner steam line 32. In this way, waste plastics, which are melted in a melting container 33 by the action of a heating device 39 and conveyed into the conveyor pipe 16 via a feed line 34 with the aid of a gear pump 35, can be atomized even before entering the conveyor pipe 16.In this way, these waste materials experience a significant increase in their specific surface area and are thus pyrohydrolyzed and gasified extremely efficiently. Unmelted solids can be filtered out of the plastic melt using a filter 36. 37 designates a metering device for catalysts and, in particular, steelworks dust and, if necessary, lime carriers for neutralizing HCl (formed when using chlorine-containing plastics such as PVC). Reference numeral 38 denotes a mixer for the waste plastics and the catalysts. The molten waste plastics in the melting container 33 are pressurized by an inert gas. The feed device according to the . Figure 7 This ensures that the melted waste plastics enter the riser pipe 3 in a finely atomized form in the form of droplets.

Claims

1. Device (1) for utilising process gas with conversion of waste materials and formation of synthesis gas, the device (1) comprising at least one riser pipe (3) formed along an axial direction (4) and arranged vertically, a feed line (5) for the process gas opening into the riser pipe (3) and an exhaust gas treatment system (6) connected to the riser pipe (3) as well as a feeding device (7) for the waste materials with at least one conveying pipe (16) projecting over a defined length (L) into the riser pipe (3), wherein the at least one conveying pipe (16) comprises an open end (17) opening into the riser pipe (3) and the feed line (5) opens into the riser pipe (3) in the axial direction (4) below the open end (17), so that the process gas entering the riser pipe (3) from the feed line (5) can flow around the at least one conveying pipe (16), characterised in that the at least one conveying pipe (16) comprises a conveying device (22) at an end (23) facing away from the open end (17) in the form of a conveying screw arranged in the conveying pipe, a piston slide and / or a thick-flow pump, wherein preferably the at least one conveying pipe (16) comprises a widening towards the open end (17), wherein the widening is preferably conical or curved.

2. Device according to claim 1, characterised in that the feeding device (7) is formed by a plurality of conveying pipes (16) projecting radially or tangentially into the riser pipe (3), the conveying pipes (16) preferably being directed obliquely upwards with respect to the axial direction (4), or in that the feeding device (7) is formed by a conveying pipe (16) projecting at a lower end of the riser pipe (3) in the axial direction (4), in particular concentrically, into the riser pipe (3).

3. Device according to claim 1 or 2, characterised in that the at least one conveying pipe (16) comprises fins (25) extending radially into the interior of the conveying pipe (16) and preferably the at least one conveying pipe (16) comprises an axially mounted rotor (26).

4. Device according to one of claims 1 to 3, characterised in that the at least one conveying pipe (16) comprises a refractory casing (24).

5. Device according to one of claims 1 to 4, characterised in that the at least one conveying pipe (16) is designed for introducing oxygen and / or H2O into the riser pipe (3), wherein preferably a feed line (18) different from the at least one conveying pipe (16) opens into the riser pipe (3) for oxygen and / or H2O.

6. Device according to one of claims 1 to 5, characterised in that the at least one conveying pipe (16) comprises on its circumference a plurality of pipes (30) which open at the open end (17) of the conveying pipe (16) and are arranged to convey water and / or water vapour to the open end (17).

7. Device according to one of claims 1 to 6, characterised in that the at least one conveying pipe (16) in the riser pipe (3) is concentrically surrounded by an outer water vapour line (31).

8. Device according to one of the claims 1 to 7, characterised in that an inner water vapour line (32) is arranged concentrically in the at least one conveying pipe (16), the inner water vapour line (32) and the conveying pipe (16) converging outside the riser pipe (3) and the conveying pipe (16) entering the riser pipe (3) overhanging the inner water vapour line (32).

9. Device according to one of claims 1 to 8, characterised in that the conveying pipe (16) is connected to a melting container (33) for plastic via a feed line (34), the melting container (33) preferably being pressurised with an inert gas, in particular with nitrogen.

10. Device according to one of claims 1 to 9, characterised in that a cooling device (8) is arranged inside the riser pipe (3) in order to cool the gas in the riser pipe (3), the cooling device (8) preferably consisting of an alloy of iron, cobalt, molybdenum and / or chromium and / or in that a heating device is arranged inside the riser pipe (3) in order to heat the gas in the riser pipe (3), the heating device preferably consisting of an alloy of iron, cobalt, molybdenum and / or chromium.

11. Device according to one of claims 1 to 10, characterised in that the exhaust gas treatment system (6) comprises a gas cyclone (11) and / or a bag filter (12) and preferably a recirculation device (10) for fine dust, in particular heavy metal fine dust, from the gas cyclone (11) and / or the bag filter (12) opens into the riser pipe (3).

12. Device according to one of claims 1 to 11, characterised in that between the riser pipe (3) and the exhaust gas treatment system (6) there is arranged a converter pipe (27), preferably coaxially connected to the riser pipe (3), with an enlarged diameter compared to the riser pipe (3), wherein the converter pipe (27) preferably consists of an alloy of iron, cobalt, molybdenum and / or chromium, wherein a gas-permeable tray (29) is preferably arranged between the riser pipe (3) and the converter pipe (27), preferably in the form of a wire mesh, a cross-grid, a perforated plate, a grate or a ceramic deep-bed filter.

13. Device according to claim 12, characterised in that a recirculation device (10) for fine dust, in particular heavy metal fine dust, from the gas cyclone and / or the bag filter opens into the converter pipe (27).

14. Method for utilising process gas with conversion of waste materials, in particular wood chips, biomass, waste fractions, waste plastics, waste solvent, shredder light fraction, waste wood and the like, and with formation of synthesis gas, in which method the process gas is fed into a vertically arranged riser pipe (3) formed along an axial direction (4) and the waste materials are pyrolysed by process gas flowing around at least one conveyor pipe (16) of a feeding device (7) and a reaction of the process gas with the pyrolysed waste materials to form synthesis gas takes place in the riser pipe (3), characterised in that steel mill dusts are added to the waste materials, in particular in the case of waste plastics, before they enter the conveyor pipe (16), the steel mill dusts preferably being oxidised after their reduction by the addition of steam to form H2, wherein preferably the conversion of waste materials, in particular wood chips, biomass, waste fractions, waste plastics, shredder light fraction, waste wood takes place with the formation of synthesis gas at process gas temperatures of 700°C to 1800°C, preferably 700°C to 1700°C, more preferably at 700°C to 1600°C.

15. Method according to claim 14, characterised in that the conversion of the synthesis gas in the sense of a water-gas shift reaction takes place in the riser pipe (3) with cooling, preferably at temperatures of initially 700°C to 380°C at the end, and / or in a converter pipe (27), preferably coaxial, connected to the riser pipe (3) with an increased diameter compared to the riser pipe (3), wherein the converter pipe (27) is preferably composed of an alloy of iron, cobalt, molybdenum and / or chromium, wherein water and / or steam are preferably supplied to the riser pipe (3).

16. Method according to claim 14 or 15, characterised in that CO2 in the synthesis gas is measured and the addition of waste materials is increased if the CO2 content in the synthesis gas is greater than 2% by volume.

17. Method according to one of claims 14 to 16, characterised in that the conversion of the synthesis gas in the converter pipe (27) takes place in a fluidised bed (28) of steel mill dust and / or in a ceramic deep-bed filter.

18. Method according to one of claims 14 to 17, characterised in that solid components are separated by means of a gas cyclone (11) and / or bag filter (12) connected to the riser pipe (3), fine dust, in particular heavy metal fine dust, being preferably returned from the gas cyclone (11) and / or the bag filter (12) to the riser pipe (3) and / or the converter pipe (27).

19. Method according to one of claims 14 to 18, characterised in that alkalis and / or alkaline earths are fed to the riser pipe (3) and / or the converter pipe (27).