EP0443596B2 - Pyrolysis process and apparatus for carrying out the process - Google Patents

Description

The invention relates to a Pyrolysev experienced for degassing waste of all kinds and to devices for performing the method.

Waste disposal methods that have been practiced or tested so far are inadequate and unconvincing with regard to the environmental problems that arise. This applies both to the intermediate storage as well as to the transport from and to the disposal facilities and especially to the processing of the waste. The term waste is understood to mean normal household and industrial waste, industrial wrecks, but also special waste or landfill that has already been deposited.

The classic form of disposal of household and industrial waste of all kinds is still today the dumping in mostly large-scale landfill systems with sometimes very long transport routes.

Waste incineration plants are a known alternative solution to landfill filling. However, burning waste has many other disadvantages. So far, combustion has been carried out with very poor efficiency and a high level of pollutants. Considerable investment and operating costs are required for the relevant incineration plants.

With the likewise known degassing of organic waste, attempts have been made to avoid waste incineration at least for part of the waste to be disposed of in order to be able to operate economically justifiable small plants.

• 1. Schachtöfen, in die das Pyrolysegut von oben lose eingebracht wird und den Ofenschacht in vertikaler Richtung durchläuft,
• 2. Drehrohröfen, bei denen durch Rotation des Rohrschachtes das schüttfähige Pyrolysegut durchmischt und mit den heißen Rohrwänden ständig erneut in Kontakt gebracht wird, und
• 3. Wirbelschichtöfen, bei denen ein in ständig verwirbelter Bewegung befindliches Sandbett o.dgl. für einen innigen Wärmeübergang in das Pyrolysegut Sorge tragen soll.

Various pyrolysis processes are known which differ with regard to the furnaces used for this. The following are used:

• 1. shaft furnaces in which the pyrolysis material is loosely introduced from above and passes through the furnace shaft in the vertical direction,
• 2. Rotary tube furnaces in which the pourable pyrolysis material is mixed by rotating the tube shaft and is brought into contact again and again with the hot tube walls, and
• 3. Fluidized bed furnaces in which a sand bed or the like which is in constant swirling motion. should ensure an intimate heat transfer into the pyrolysis material.

In addition to these three essential types of furnace, WO 81/03629 describes a procedure in which moist waste is subjected to pyrolysis and is dewatered by pressing together before passing through this stage. The major part of the liquid, including organic components, is removed.

The waste compressed into blocks is heated from the outside in a furnace and pyrolyzed in order to avoid caking or aggravating the feed, an expanding chamber cross section of the furnace is used, which prevents the blocks from all-round contact with the wall. The pyrolyzed material is then burned in a downstream shaft and the resulting hot exhaust gases are used to heat the blocks in the pyrolysis stage.

Further degassing reactors are known for example from AT-PS 116 725 and AT-PS 363 577. They show a large number of problems that have not yet been solved satisfactorily. To improve the heat transfer, the waste to be pyrolyzed must be pre-shredded, which causes high costs, noise pollution and dust. It is also necessary that atmospheric air has to be introduced in large throughputs, possibly with additional oxygen, with the organic constituents for pyrolysis, which results in only a low efficiency. The heating of the waste is relatively slow. The pyrolysis furnaces with economically justifiable throughput have a large volume and are at the limit of mechanical strength at the required temperatures of over 450 ° C. They are only suitable for operation at around atmospheric pressure. In order to prevent gaseous pollutants from escaping, the degassing reactors must be absolutely gas-tight, which necessitates expensive, temperature-sensitive lock constructions and seals.

So far, the further processing of the essentially dusty pyrolysis coke has also been particularly problematic, since its gasification is not possible or only possible after briquetting of the coal dust, which is complex in terms of process technology, because of its non-existent flow properties. A thermal use of the gases from the low-temperature pyrolysis, which are contaminated by condensate, requires dedusting at correspondingly high temperatures, since both the rotary kiln and the fluidized-bed pyrolysis generate a lot of dust. The exposure of the pyrolysis gases to thermally stable organic compounds, such as dioxins, requires high-temperature combustion with defined gas residence times in the reactor. The use of condensates, which are highly contaminated with pollutants, as a raw material for petrochemicals is only possible in exceptional cases. In other cases, the pyrolysis condensate is a significant environmental problem. The solid residues of the known pyrolysis processes are landfill material containing pollutants according to the existing environmental regulations. Whether the carbon content of these residues has sufficient pollutant-binding properties is unclear, at least with regard to long-term resistance to elution, so that pyrolysis coke from waste pyrolysis as hazardous waste with corresponding landfill risks and costs is to be considered.

When it comes to the environmentally friendly processing of industrial wrecks, where the scrap mixture consists of iron parts and parts made of non-ferrous metals and non-metallic organic and inorganic components with a wide variety of chemical and physical compositions, the automotive industry in particular, in conjunction with the plastics industry and the scrap industry, is encouraged to take new approaches research on the recycling-compatible design of motor vehicles and the development of recycling processes and technologies for materials that are not yet usable today. Significantly increased landfill costs and stricter conditions for the disposal of industrial waste in a landfillable form are forcing the non-recyclable portion in the processing of consumer wrecks to be kept as low as possible.

The operation of large scrap presses in the application area of interest has been replaced by the so-called shredder technology for some time. Disused consumer goods and industrial goods with a high metal content that are suitable for scrapping are subjected to purely mechanical material separation. Part or all of the wrecks to be processed are fed into the comminution system, in which a small-scale mixture is produced from the multiplicity of components of the starting material, which is then preferably separated using physical methods.

In a known method (EP 0 012091), comminuted waste is subjected to a heat treatment in a closed space in that some constituents are burned while supplying an oxygen-containing combustion gas, while other constituents are subjected to a pyrolysis reaction. The combustion is only completed in a second combustion stage by adding pure oxygen and thus increasing the temperature to 1,300 to 1,600 ° C.

In this context, reference should also be made to a device for the selective separation of nonferromagnetic metals from a mixture of comminuted metallic scrap, such as occurs in shredder plants (DE-AS 28 55 239). in which several assigned discharge devices are provided via different heat baths with different, corresponding to the melting points of the non-ferrous metals, such as lead, zinc and aluminum.

After the different non-ferrous components have been removed, that of the ferromagnetic components is then carried out by magnetic sorting. The great difficulties in the recovery of scrap metals, which consist of mixtures, for example with copper, zinc and lead components, with a view to sufficient creation of the required levels of purity and thus economic reuse are particularly clearly addressed in this publication.

A process for the pyrolytic degradation of industrial and household waste or similar waste materials, in which the waste materials are decomposed in a reaction vessel by direct contact with a molten heat transfer medium, is known from DE-AS 23 04 369. The appropriately preheated waste materials are continuously immersed in the molten heat transfer medium and the resulting decomposition products are conveyed to the surface by circulating the melt and are removed from there. The heat transfer medium is a molten inorganic substance and can therefore consist of one or more metals, or alternatively also of a glass-like melt which is kept molten by the application of heat.

This procedure is intended to enable large quantities of heterogeneously combined waste materials to be pyrolytically broken down in an air-tight manner without complex pre-classification in a continuous workflow and to be converted into harmless or useful products.

The direct contacting of such pre-dried waste mixtures with a molten heat transfer medium, into which the feed pipe for the waste materials is immersed, is not possible in practice, since the residual waste moisture must lead to an explosive gas formation at the outlet end of the feed pipe. In addition, the pipe socket immersed in the melt would be used up relatively quickly.

Carrying out the pyrolysis within the molten bath has the effect that the pyrolysis products ultimately accumulate on the surface of the melt and that all of them must be removed from here. With this procedure, it cannot be ruled out that highly toxic pollutant components will escape from the bath liquid. The connection of electrostatic filters as well as washing-out systems and cold traps to remove the pollutants that are still present therefore remains mandatory even in the process according to DE-AS 23 04 369.

Finally, a process for the largely water-free transfer of waste materials into glass form should be mentioned (DE-OS 38 41 889), in which waste incineration ash is introduced together with additives in a glass melt, the resulting exhaust gases are cooled and their condensates are returned to the glass melt. The exhaust gases free of dioxins and / or furans can be released in an environmentally friendly manner after gas cleaning, which is equally true for those in the glass bath mineralized solids, i.e. the combustion ash, applies.

The main problem with any exhaust gas cleaning system is to be found in the remaining residues. These are available as reaction products in the form of dry crystals, dissolved salts and / or dusts that are highly contaminated. The disposal of these residues, which occur in large quantities, is problematic and requires constantly growing special landfill space.

The storage and transportation of unprepared waste, such as industrial and domestic waste, takes place with a relatively low bulk density, whereby their physical and chemical instability, as well as the development of odor and gas in the case of biologically decomposable waste, have a particularly disadvantageous effect. It is aggravating that many disposal goods contain pollutant-containing liquids, which they at least partially lose during transport or storage. Leaching due to precipitation can hardly be avoided if improperly stored. The low bulk density of the material to be disposed of leads to large storage and transport volumes. If the waste to be disposed of is intended to be stored temporarily - for example because the waste to be recycled and / or thermally recycled - state regulations stipulate that landfill facilities that are washable, have a substantial construction volume or specially equipped underground storage facilities. This alone results in high additional investment costs. The transportation of such disposal goods also causes considerable costs, not least because of their low bulk density.

In the case of chemically unstable waste, in addition to strong odors, toxic or dangerous gas formation can occur, so that there is a risk of explosion, especially for storage bunkers without additional gas disposal. Permanent ventilation, multiple air changes per hour as well as additional filter and safety systems are cost factors also for the temporary storage of the waste.

For the transport of some disposal goods, for example household waste, it is known to transport slightly pre-compressed with presses integrated in the vehicle. Subsequent thermal recycling of the material to be disposed of is made technically difficult by its low bulk density and the resulting large volumes.

Starting from the entirety of this prior art, in particular from WO A-81/03629, the present invention is based on the object of improving pyrolysis, in particular heat transfer, and of specifying a corresponding device.

The object is achieved by the features specified in the characterizing part of claim 1.

Advantageous further developments and refinements of this task solution result from the subclaims.

Characterized in that the waste is initially precompacted while maintaining its mixed and composite structure, i.e. without the use of expensive sorting methods and systems or the known prior art to packages of approximately the same geometry, the waste can be easily with a stuffing device or the like. are compressed into, for example, an approximately tubular container, which makes both its subsequent transport, any intermediate storage that may be required and the pyrolysis process uncomplicated and unaffected by faults. The pre-compaction into a suitable geometric shape, which according to the invention is adapted to a suitable container, prevents bulky constituents of the material to be disposed of hindering the subsequent compaction process during the subsequent compaction. In the compressed state, the material to be disposed of only has approximately 1/3 to approximately 1/20 of its original volume, which results in a correspondingly reduced storage and transport volume, regardless of a subsequent thermal degassing or pyrolysis of the material to be disposed of.

Advantageous conditions for the thermal recycling of the pyrolyzed disposal goods are that all degassing products can be subjected to a high-temperature treatment directly and without intermediate cooling. The resulting compressed coke, together with the mineral or metallic components, can be easily removed and subjected to high-temperature treatment. During the gasification of the residual carbon, fission gas (CO, H2) is generated by splitting part of the water vapor carried along. The degassing products are split into low molecular weight components. The reaction temperature is maintained by exothermic reaction of the coke in compressed form with oxygen. The carbon dioxide released in this way reacts with carbon to carbon monoxide according to Boudouard's equilibrium. Optimal implementation and use of all products is ensured in the high-temperature reactor.

The high temperatures associated with carbon gasification and fission gas formation lead to a directly usable, high-energy process gas without condensable organic constituents being obtained with a greatly reduced water content. The dense coke formed in the pressure pyrolysis and the process-related low flow velocities reduce the amount of dust in the process gas to a minimum.

During the high-temperature treatment in a melter gasifier, the meltable metallic and mineral components of the reaction products form a metal or slag melt with partially very different densities, so that material components can be separated easily and can be used efficiently.

The carbon gasification and fission gas formation, coupled with the melting out of usable valuable materials, can also be carried out in an advantageous manner in a shaft furnace of known type, with oxygen being supplied to the shaft containing the compressed process coke in a known manner. Temperatures of more than 1,500 ° C can be easily generated in the solid pyrolysis residues, at which steel and other metals as well as glasses melt. These recyclables can be discharged in fractional tapping or in an overflow. The use of oxygen instead of air is of considerable advantage in order to achieve high temperatures, low gas velocities and volumes and to avoid the formation of nitrogen-oxygen compounds.

The escape of the volatile compounds formed by thermal cleavage from the tightly filled containers is favored if the front side is open and perforated metal pipes or the like. be used. With appropriate dimensioning, optimal conditions result with regard to the gas outlet, the manufacturing costs and the applicable degassing temperatures.

The material to be disposed of can also be pre-compacted for transport and intermediate storage in thermally decomposable containers made of mechanically solid material and later compacted in the thermally stable degassing pipes which are subjected to pyrolysis.

The compaction of household waste or the like. can be significantly improved if a sterilizing hot gas, preferably superheated steam, is applied to the material to be disposed of during the pre-compaction. This increases the possibility of its plasticization and the chemical stability of the material to be disposed of, as well as the shelf life without odor and gas formation.

Because of the desired high thermal conductivity to and within the disposal material for pyrolysis, but also for reasons of storage, transport and optimal disposal volume for degassing, it is advisable to fill the container so that the filling density of household waste is approx. 1 kg / dm is ³ . A periodically operating hammer, which is driven mechanically, hydraulically or pneumatically, can be used as the stuffing device for the compacting filling of the containers.

If the densely filled containers are temporarily stored before they are sent for thermal recycling, then it is advantageous if the end faces of the tubular container filled with post-compacted waste are covered with thermally decomposable films or coatings. In this way, direct releases of pollutants to the environment are excluded, and, on the other hand, unpleasant smells are avoided. The thermally decomposable cover can be used thermally in the subsequent pyrolysis. In addition to plastic foils, bituminous coatings are suitable for this purpose, which can be applied inexpensively and easily. Otherwise, the containers behave practically self-cleaning when using the pressure pyrolysis according to the invention. Their use not only optimizes the conditions for pyrolysis itself, but also reduces the transport volume by approx. 80% when used as a transport container. The result of the pyrolysis compressed pyrolysis coke has excellent flow properties, making it particularly suitable for subsequent coal gasification.

In the method described above, a part of the natural moisture of the waste is converted into combustible gas for the first time in the waste pyrolysis by the described hydrocarbon gas reaction.

In the pyrolysis process according to the invention, the pyrolysis material is introduced under compression into a pyrolysis chamber which consists of a single pyrolysis tube or a channel-like pyrolysis furnace and, while maintaining the compressed state, is pressed through the heated cross section through the heated tube or the channel, with the heat being supplied to the pyrolysis product by the same walls are in contact with pressure and the gaseous pyrolysis products that form are removed at elevated pressure.

The forced conveyance of the compressed pyrolysis material ensures constant pressure contact between the pyrolysis material and the heated chamber wall, so that the heat transfer from the chamber walls to the pyrolysis material is optimized.

In addition, the volume loss in the pyrolysis chamber due to degassing (pyrolysis gas / water vapor) and / or discharge of solid components is compensated for by refilling and recompressing with pyrolysis material.

The higher pressure in the pyrolysis chamber guarantees a better forced flow of the pyrolysis material and the pyrolysis coke through the gaseous pyrolysis components, which leads to better heating and in addition to a shorter degassing time, so that a high performance of the system is guaranteed.

Compression, forced conveyance and post-compression of the pyrolysis material are carried out intermittently in an advantageous process development.

The pyrolysis material and the solid residues can be introduced in a simple manner in that the tubular or channel-shaped pyrolysis chamber may have adjustable cross-sectional constrictions on its inlet and outlet sides, so that plugs also form on the outlet side. The self-sealing plug is constantly renewed by the continuous feeding and compression of pyrolysis material.

When using such an elongated pyrolysis chamber according to the invention, into which the waste material is introduced while maintaining a compacted state, while working continuously, there is very good thermal conductivity for and into the compacted waste material because of the air-pore-free pressure contact with the wall of the chamber. The use of pyrolysis chambers whose length to diameter is greater than 10: 1 has proven to be an advantageous length / diameter ratio.

A batchwise, i.e. Intermittent forced conveyance of the pyrolysis material or the post-compacted solid residue also has the advantage that, in cooperation with the pressure contact of the pyrolysis material with the chamber walls, incrustations and caking of pyrolysis residues on the chamber walls are removed by constant friction of the pyrolysis material that advances. The pyrolysis chamber is self-cleaning in such an embodiment. It also does not contain any moving components that lead to malfunctions during long-term operation and can cause difficulties, particularly with regard to sealing and lubrication.

The solid pyrolysis residues are advantageously brought out in the hot state (approx. 400 ° C.) in a melting cyclone (post-combustion chamber) and burned there with the addition of oxygen or melted to form slag.

The entire energy content of the hot pyrolysis coke can be used directly.

When using pure oxygen or at least oxygen-enriched air, the high nitrogen content of the air does not have to be heated, so that the exhaust gas volume is considerably reduced and the exhaust gas cleaning can be controlled technically well and is more economical.

The high carbon content of the residual material resulting from low-temperature pyrolysis has good pollutant-binding properties. This can be further supported by adding pollutant-binding additives to the pyrolysis material before compression.

Another particular advantage results from the fact that the gaseous pyrolysis products exit the pyrolysis chamber at the end of the conveying path. In this case, the hot gaseous pyrolysis products on the one hand flow through the full length of the pyrolysis material, and on the other hand the pyrolysis chamber is thereby depressurized only immediately before being dispensed, which simplifies the sealing of the pyrolysis chamber on the outlet side. In accordance with the resulting flow of the gaseous pyrolysis products and the resulting pressure drop along the pyrolysis chamber, the highest pressures prevail on the introduction side and here ensure both rapid heating and rapid degassing.

Optimal heat transfer through pressure contact, optimized thermal conductivity by reducing the pore volume and additional volume heating by the gaseous pyrolysis products themselves are advantages of the pyrolysis process according to the invention with respect to the heating of the pyrolysis product compared to the prior art. By pyrolysis Even the thermal conductivity of the pyrolysis material is constantly being improved, especially in the contact zones of the walls, so that the areas that have already been preferably pyrolyzed pass on the heat to the interior areas, which have not yet been so far pyrolyzed, by good heat conduction. An additional effect is given by the fact that the carbon-rich residues have much better heat conduction in the compressed or post-compressed state than the original pyrolysis material. The state of compaction of pyrolysis material and residues according to the invention and the constant pressure contact of the pyrolysis material with the chamber walls not only minimize the necessary dimensions of the pyrolysis chamber, they also considerably shorten the necessary pyrolysis time.

In the processing of industrial wrecks, such as passenger cars, refrigerators, washing machines and the like, large-volume portioning of the scrap material, cutting and / or upsetting while maintaining its mixed and composite structure mean that scrap packages are easy to handle with minimal preparation. In particular, by upsetting the industrial wrecks, it is possible to obtain scrap packages of approximately uniform external dimensions, which facilitates their handling in the pyrolysis chamber. The portioning of the scrap is expediently carried out in such a way that sufficient degassing volumes remain. The large-volume portioning also makes it easier to load the pyrolysis chamber with the help of intermittently working loading and unloading devices for the scrap material.

In particular when the method is applied to vehicles to be scrapped, it may be expedient to carry out the large-volume portioning of the scrap by structurelessly dividing it into relatively large wreck sections. In this way, the size of the pyrolysis portions can be limited. The cutting can be done with the help of tear grippers as well as other cutting or separating methods. Dipping the wreckage sections obtained in this way to predetermined dimensions can be expedient to simplify handling.

The afterburning of the pyrolysis gases can be carried out in a separate part of the pyrolysis chamber in the process according to the invention, which has the advantage that part of the heat of combustion can be used directly to maintain the pyrolysis. However, it will often be advisable to carry out the low-pollution post-combustion in a separate post-combustion chamber. In this case, the combustion conditions can be controlled more precisely, which ensures that the exhaust gases are free of harmful substances.

An easier handling - and thus an advantageous further development of the method - can consist in the fact that the mixed scrap, combined in collecting containers, passes through the pyrolysis chamber. Such a procedure is particularly expedient when different consumer wrecks are used whose outer dimensions are very different.

The temperature of the pyrolysis chamber is expediently controlled so that when the degassing and at least partial gasification of the pyrolysis-compatible components of the scrap is complete, the melting temperature of the slag residues is not reached. This procedure has advantages: the pyrolysis residues do not melt onto the metallic components of the scrap and can be easily separated, and the pyrolysis residues that have not yet been mineralized (melted) still contain in porous form, i.e. with a large active surface, absorbent carbon for binding pollutants.

Mixed scrap generally contains only a limited amount of pyrolyzable material. For example, the non-metallic components of a vehicle of a conventional design amount to less than 30%. For reasons of disposal of a region as well as for energy reasons, it may therefore be advisable to add waste with a higher calorific value to the mixed scrap. This can be done in a simple way by using the consumer wrecks themselves as "containers" by partially filling their remaining cavities with this waste. Another possibility is to first compact the additional waste together with the portioned wrecks into the containers mentioned and then send them into the pyrolysis chamber. Another possibility for developing the process according to the invention is that several pyrolysis chambers are assigned to afterburning. In particular, if separate afterburning chambers are provided, this possibility brings advantages if the loading of the pyrolysis chambers takes place with a time delay such that the sum of the gas developments can be kept approximately constant.

Both in the processing of domestic and industrial waste as well as industrial wrecks or the like. The pyrolysis products that are disposed of generally contain pollutants that must not be released into the environment.

According to the invention, therefore, in a preferred embodiment, the solid, liquid and / or gaseous process products obtained during the pyrolysis and containing the pollutants are passed into one or more melt baths which are kept at different temperature values and / or have different compositions. Because the pyrolysis products containing pollutants by melt baths conducted, the temperature values of which can be in the range of 1,500 ° C to 2,000 ° C, it is possible to optimally set both the decomposition temperatures of organic pollutants and, for example, the condensation temperature of inorganic pollutants in individual baths and to keep them constant within narrow limits. Depending on the application, a melting tank can suffice.

In the high-temperature melt baths, the organic pollutants are first completely decomposed. It has a particularly advantageous effect that the flow through at least one melt pool is associated with much lower speeds than the combustion of the contaminants in a gas burner according to the prior art. In the high-temperature liquid, the contact times between contaminated gas or liquid and / or solid contaminations are favored in such a way that longer distances can be dispensed with. The method according to the invention can work with a device structure which is of a considerably simpler and more compact design than the known comparable systems. Passing the pollutant-laden gaseous pyrolysis products through a high-temperature molten bath requires, as in conventional filter systems, a certain pressure drop, which can be generated both by pre-compressing the pollutant-containing materials to be passed through and fed to the high-temperature molten bath under excess pressure, and by the fact that the molten bath is included Vacuum is applied.

The melting baths can consist of one or different materials that melt at the high temperatures in question. In addition to the desired temperature range, the choice of material for the baths depends on the pollutant conversion aimed for in the bath in question. Metallic baths are cheap for the conversion of certain pollutant combinations. Melting baths made of glass can be adjusted in terms of their viscosity to a large temperature range in such a way that the pollutant-containing material can be passed through and divided without problems. In addition, glass also has excellent integration properties for solid inorganic pollutants. For example, lead and arsenic are so-called network formers in the existing glass structures, which can be installed in appropriately formulated glasses without problems and resistant to leaching with a high absorption capacity. Another advantage of using glasses as a high-temperature melt bath is the fact that any unsorted, otherwise difficult to use used glass can be used.

If the method according to the invention is applied to the post-cleaning of waste pyrolysis products, the unavoidable waste glass portion of the household waste can be used directly. In the case of glass melts whose temperatures are above 1,200 ° C., it is ensured that all organic pollutants that could be contained in the exhaust gases are completely decomposed, in particular also dioxins or furans.

In addition to the above-mentioned metal and glass melting baths, baths consisting of molten salts offer the advantage that pollutant components such as chlorine, fluorine and sulfur or the like are neutralized here and converted into environmentally neutral compounds. Depending on the type of pollutant and pollutant composition of the pyrolysis products, it is advisable to connect several melt baths in series, whereby they can be staggered according to the temperature so that the temperature of the previous bath is always higher than that of the bath following in the process. This advantageously has the effect that the heat given off by the pyrolysis products heats the subsequent bath in the process sequence, so that external heating can largely be dispensed with. In such a cascade-shaped bath arrangement, the high-temperature baths can additionally be heated by burning the pyrolysis coke obtained with the supply of oxygen. In the baths of the cascade mentioned, which have lower temperature values, pollutants which remain volatile at temperatures at which organic substances are decomposed can be condensed and chemically integrated so that they can be applied in insoluble form.

The scientific knowledge currently available on the decomposition of organic pollutants and the integration of inorganic pollutants in the form of mineralization in combination with an additional pollutant condensation show that the process according to the invention guarantees that the gases treated in this way are free of pollutants. Measuring monitoring of the gases freed from pollutants can either be omitted or reduced to a minimum, for example by monitoring a guiding element or a guiding connection.

The gas-tight arrangement of a high-temperature bath or a melt pool cascade directly at the discharge opening of the pyrolysis reactor makes locks susceptible to faults unnecessary.

The differences in the specific weight between glasses and metals as well as salt melts allow the fractional application of recyclable materials carried in the pyrolysis residues in melt baths of the appropriate temperature in a simple and hygienically perfect manner.

The pyrolysis technology used so far assumes that the waste is warmed up by loosening To improve and accelerate, which leads to expensive processing plants and voluminous pyrolysis furnaces, the reactive compaction according to the invention is based on the observation that by compressing loose mixed waste, the thermal conductivity in the material to be pyrolyzed can be improved to such an extent that the pyrolysis in it compacted state becomes problem-free. This is why we speak of low-temperature pressure pyrolysis. The contents of the waste, which can be found in the melt baths, also improve the thermal conductivity during pyrolysis; Inert substances, such as glass, do not interfere with the process.

Reactive compacting therefore offers all the prerequisites to meet the requirements for modern, economical disposal of waste products, especially since there are no fundamental restrictions for the function of smaller plants.

• Figur 1 eine schematische Schnittdarstellung einer ersten Ausführungsform der erfindungsgemäßen Vorrichtung mit einem einzigen Pyrolyserohr mit zugeordnetem Einschmelzvergaser;
• Figur 2 eine noch weitere, besonders vorteilhafte Ausführung einer Durchlauf-Pyrolysekammer mit nachgeschaltetem Einschmelzofen und
• Figur 3 eine Draufsicht auf die Ausführungsform gemäß Fig. 2.

Three device structures for reactive compacting, for example, the low-temperature pressure pyrolysis, the transport and intermediate storage options according to the invention given by the pre-compression, and the high-temperature treatment are explained in more detail with reference to the drawings, which are only intended to represent schematic embodiments in a greatly simplified form. Show it:

• Figure 1 is a schematic sectional view of a first embodiment of the device according to the invention with a single pyrolysis tube with an associated melter gasifier;
• Figure 2 shows yet another, particularly advantageous embodiment of a continuous pyrolysis chamber with a downstream melting furnace and
• FIG. 3 shows a top view of the embodiment according to FIG. 2.

In Fig. 1, a heatable tube, hereinafter referred to as pyrolysis tube 1, is arranged vertically above a molten bath tank 10 and connected to it in a gastight manner. The tube provides a pyrolysis chamber. The material is transported between the tube and the melt pool container 10 supported by gravity. Elaborate, temperature-loaded and fault-prone transport devices are eliminated. A pre-compression device for the pyrolysis material to be filled into the upper opening of the vertical pyrolysis tube 1 on the loading side should be provided in a suitable manner, but is not shown for reasons of simplification. A pre-compression device has the advantage of being able to feed bulky pyrolysis material to the pyrolysis tube 1 without prior treatment. The supply of the pyrolysis material is favored by a funnel-shaped expansion of the pyrolysis tube 1 in the upper opening area. A tamping device 2 moves periodically into the funnel-shaped enlargement and spends the pre-compressed pyrolysis material in and through the pyrolysis tube 1.

The tamping device 2 is a pneumatic, hydraulic or gravity-operated hammer, as is commercially available in a comparable design and mode of operation, for example for driving in sheet piling or foundation piles. The hammer is guided with the help of guide rollers or other suitable guides to the pyrolysis tube in such a way that it can be moved up and down in the vertical direction. Its plunger 2 'has a shaped head piece with which the pyrolysis material is periodically plugged or hammered into the pyrolysis tube 1. The only non-positive connection between the pyrolysis material and the hammer has the essential advantage that no inadmissibly high forces can occur in the loading area, which are otherwise inevitable with a positively driven tamping device. Particularly solid components in the pyrolysis material, such as metal parts or the like, could otherwise lead to overloading of the stuffing device. This is excluded in the device as described above. The pyrolysis tube 1, which receives unsorted pyrolysis material, which is moved through it intermittently over its entire length, has a length / diameter ratio of greater than 1:10. In the case of tubes of this geometry, the feed rate of the pyrolysis material can be adapted particularly advantageously to the compression state of the pyrolysis material in the pyrolysis tube 1 and thus to the pressure on the walls of the pyrolysis tube. The pyrolysis material leaves the mouth of the pyrolysis tube 1 completely pyrolyzed with an optimized throughput.

The pyrolysis tube 1 is expediently heated by gas burners 9 acting from the outside, which are arranged distributed along the tube within the heating jacket 16. External heating with gas burners has the great advantage that the pyrolysis gases can be used directly for this. The interposition of a control device 8 between the gas outlets 6 from the pyrolysis tube 1 and the burner 9 allows the process control in a simple manner. The pyrolysis tube 1 is heated to temperatures between 250 ° C. and 500 ° C., the charging area of the pyrolysis tube being excluded from the heating. In this area, a solid stopper is formed when the plug is plugged, which prevents the gas from escaping from the mouth of the pyrolysis tube in the open and that constantly renews itself. This is a major advantage, since gas-tight feed locks, which have proven to be prone to failure in pyrolysis systems, are completely unnecessary. The exhaust gases from the gas burners 9 are collected in the jacket 16 and fed to an exhaust gas chimney through an outlet 7, optionally via a filter system. The outlet openings 6 for the pyrolysis gases from the pyrolysis tube 1 are located in the vicinity of the mouth region of the pyrolysis tube. They are collected in a ring line and fed to the control device 8 for distribution. Not shown in FIG. 1 is the advantageous possibility of preheating the combustion air for the operation of the gas burners, for example by guiding along the outer surfaces of the heating jacket 16, and / or enriching the combustion air with oxygen. The increase in the flame temperature of the burners associated with these measures guarantees the decomposition of organic pollutants in the pyrolysis gas and thus the absence of pollutants in the exhaust gases.

The outlet area of the pyrolysis tube 1 has a conical narrowing part 14, the cross section of which can be regulated if necessary. With this constructive measure it is achieved that the remaining solids of the pyrolysis are post-compressed, whereby the outlet area of the pyrolysis tube 1 is sealed against gas leakage. The back pressure in the pyrolysis material associated with this post-compression favors its compression during the stuffing and improves the overall process of pyrolysis.

The melt pool 10 is arranged in alignment under the pyrolysis tube 1. It is provided with a fire-resistant inner lining 11 which can be subjected to a temperature above 1,300 ° C. The melting bath is heated with the help of the gas burners 9 ', which are directed onto the surface of the melting bath. Their effect can be supported by means of a controllable oxygen supply, not shown in FIG. 1. With the help of the oxygen supply, carbon-containing pyrolysis residues can be completely combusted, which on the one hand reduces the amount of solid residues, but on the other hand also adds thermal energy to the melt pool. An oxygen supply is also possible due to excess oxygen in the combustion gas of the burners 9 '. The high melt bath temperature leads to mineralization of the pyrolysis residues. The mineralized slag guarantees a leach-proof inclusion of any pollutants and thus turns the residues into environmentally friendly or inert materials for the building materials industry or the like.

Waste glass contents of the pyrolysis material favor these properties. Sorting out the old glass before pyrolysis is not necessary. The physical properties of the melt pool 12 in the melt pool container 10 can be improved by additives which are added to the pyrolysis material before it is introduced into the pyrolysis tube 1. Surcharges of lime or dolomite both bind pollutants during pyrolysis and liquefy the slag in the molten pool.

According to the representation in Fig. 1, the outlet area of the pyrolysis tube 1 is followed by a dip tube 13 immersed in the molten bath 12, which prevents the transfer of dust from the pyrolysis residues into the gas space of the molten bath container 10 and ensures the direct introduction of the residues into the melt. The exhaust gases from the molten bath container 10 are returned to the pyrolysis gases through an exhaust gas line 18. Your possible pollutant content is made harmless by the afterburning in the gas burner 9 or 9 '. The possible reduction in the calorific values of the pyrolysis gases associated with the gas recirculation is largely compensated for by the higher temperature of the exhaust gases of the melt pool container 10.

The high temperature of the melt pool for the pyrolysis residues not only enables effective pollutant incorporation through mineralization, it also offers the possibility of separating valuable ingredients from the pyrolysis material. If, for example, the temperature of the molten bath 12 is selected to be greater than the melting temperature of steel, mineralizable light materials which float on the molten steel can be fractionally discharged through several overflows at different heights of the molten bath container. The separation of recyclable metals not only reduces the landfill space required, but also increases the effectiveness of the process.

The operation of the device shown in FIG. 1 is as follows: The periodic tamping movement of the device 2. 2 'in the direction of the arrow causes the pyrolysis material to be highly compressed in the unheated mouth region of the pyrolysis tube 1 and forms the desired sealing plug. Due to the continuous pushing through of the pyrolysis material, this plug is always newly formed and results in a maintenance-free, reliable seal. With the entry into the subsequent heating section, the pyrolysis of the compressed material begins from the pipe wall. The constant replenishment of pyrolysis material compensates for the loss of mass through pyrolysis, so that the pressure of the pyrolysis material against the pipe wall, which is necessary for good heat transfer, is maintained until the end. With increasing push-through, the thickness of the pyrolyzed ring zone increases inwards from the tube wall, so that shortly before the outlet area, approximately at the level of the outlet holes 6 for the pyrolysis gas, the pyrolysis material is completely pyrolyzed. The remaining solid residues of pyrolysis eventually fall as the pyrolysis progresses Passing through the dip tube 13 into the molten pool 12, where they are melted and mineralized.

The compact design of the pyrolysis device, made possible by the principle of reactive compacting, allows the loss of uncontrolled waste heat through effective thermal insulation to be avoided and noise emissions to be suppressed by shielding.

FIGS. 2 and 3 show a further, particularly preferred exemplary embodiment of a device for carrying out the pyrolysis process according to the invention in side elevation and in plan view. The pyrolysis chamber then consists of an elongated, essentially horizontally oriented channel-like furnace shaft 40 with an inlet end 41 and an outlet end 42. Via a feed device 51, which in the exemplary embodiment is approximately box-shaped, the material to be pyrolyzed is either in the form of, for example, undensified and unsorted accruing waste or pre-compacted portioned, for example combined in thermally decomposable containers, introduced. For this purpose, the feed device 51 has a compressor 52 and a thrust ram 53. This double pushing stamp device, the stamps of which work mutually, that is, alternately, perpendicularly to one another, as can be seen in particular from the illustration according to FIG. 2, is there from above, that is again perpendicular to the two stamping movements, with waste material, the mixed and composite structure can be arbitrary, fed intermittently. The non-compacted or pre-compacted disposal material undergoes a further compacting by means of the compressor 52, whereupon it is then also intermittently stuffed into the open shaft 40 and thus the actual pyrolysis chamber by means of the push rod 53. A solid, gas-impermeable plug is thus formed on the loading side at the entry end 41 from the disposal material that is always to be replenished, and at the same time the compressed disposal material 57 is pushed through the entire cross section of the furnace shaft along the pyrolysis chamber through the intermittent tamping process, while maintaining this compressed state it is in pressure contact with the chamber walls over its entire length and also remains in this state. To carry out the low-temperature pressure pyrolysis, a heating jacket 54 is placed around the furnace shaft 40, so that the pyrolysis chamber can be heated analogously to the embodiment according to FIG. 1 described above.

The state of compaction of the pyrolysis material inside the pyolysis chamber can be both by means of an inlet-side cross-section meter 56 can also be regulated by means of an outlet-side cross-section metering device 55, whereby the outlet-side cross-section metering device 55 can also be designed, for example, in the form of an impact flap, so that it can simultaneously serve as an ejection device for the pyrolysis material at the discharge end 42 of the pyrolysis chamber. The exemplary embodiment according to FIGS. 2 and 3 shows that portioned quantities of disposal material are continuously pushed through the furnace shaft 40 here. Otherwise, the pyrolysis process in the channel-like pyrolysis chamber shown corresponds essentially to the pyrolysis process in the tubular pyrolysis chamber according to the exemplary embodiment according to FIG. 1.

The outlet 43 at the end of the furnace shaft 40 for the pyrolysis product degassed there is located in the bottom of the furnace shaft 40, which is rectangular in cross section, as shown in FIG. 4 and is connected via a gas seal 48 directly to the melt pool container 44 or a melter gasifier arranged below it. The structure or mode of operation of the melt pool container 44 is in turn comparable to that of the melt pool container 10 of the embodiment according to FIG. 1.

The melt pool container 44, which is provided with a corresponding, solid, masonry lining, receives the bath melt 46 in its lower area, on the surface of which a plurality of oxygen lances 45 are directed, and in the upper recessed area of the melt pool tank there is at least one gas vent 47 a melt bath outlet 49 is drawn in, and the melt product can be drawn off into a melt vessel 50 here.

Fig. 3 shows the longitudinal sectional view of Fig. 2 in plan view, in addition, an end flap 58 for the feeder 51 for the garbage or the like. Disposal material is indicated.

Claims (16)

1. Pyrolysis process for degassing organic substances, for example domestic and industrial waste and the like, in a heated pyrolysis chamber, characterised in that the pyrolysis goods are fed into the pyrolysis chamber whilst being compressed, and that they pass through it via the cross-section of the chamber whilst maintaining their compressed state, that the heat delivery to the pyrolysis goods is carried out by means of the chamber walls which are in constant pressure contact with the compressed pyrolysis material, and that the developing gaseous pyrolysis products are discharged under increased pressure.
2. Process according to Claim 1, characterised in that the pyrolysis chamber is in its feed area gastightly sealed by the compressed pyrolysis material, and that it has in the discharge area of the gaseous pyrolysis products an increased flow resistance due to post-compression of the solid pyrolysis residue.
3. Process according to Claims 1 and 2, characterised in that the solid pyrolysis residue is post-compressed prior to being discharged.
4. Process according to Claims 1 to 3, characterised in that the pyrolysis material is conveyed through a tubular or channelised pyrolysis chamber.
5. Process according to Claims 3 and 4, characterised in that the delivery of the pyrolysis material, its compession and its passage through the pyrolysis chamber are carried out intermittently.
6. Process according to Claim 3, characterised in that solid, liquid and/or gaseous processed products, which contain harmful substances, are passed through a plurality of melting baths which are maintained at different temperature values and/or offer different compositions.
7. Process according to Claim 6, characterised in that the processed products are passed through melting baths of reducing temperature values, so that the temperature of a respective previous bath is always higher than that of the next bath in the course of the process.
8. Apparatus for carrying out the process according to Claims 1 to 7, comprising a heatable pipe (11) having at the feed end a stuffing means (2, 2') which actively pre- and post-compresses, at least one gas discharge means near the discharge opening of the pyrolysis chamber which is at the outlet gastightly connected to a melt-bath container (10), and a cross-sectional apportioning means (14, 55) is provided at the outlet of the pyrolysis chamber.
9. Apparatus according to Claim 8, characterised by a predominantly vertically oriented arrangement of the pyrolysis pipe (1) above the melt-bath container (10).
10. Apparatus according to Claim 8, characterised in that the stuffing means (2) is a pneumatically, hydraulically of gravity operated hammer, and a stuffing tappet (2') dips into the top feed opening of the pyrolysis pipe (1).
11. Apparatus according to at least one of Claims 8 to 10, characterised by a further feed device comprising an additional pre-compression means, a transporting pipe which connects the pre-compression means to a transverse conveyer at the feed side of the pyrolysis pipe (1), and a push-through means for the pre-compressed pyrolysis material.
12. Apparatus according to Claim 8, characterised in that the pyrolysis chamber has the shape of a channelised, predominantly horizontally oriented furnace shaft (4) which is, at least over a substantial portion of its peripheral surface, surrounded by a heating jacket (54).
13. Apparatus according to Claim 12, characterised in that the pre-compression means at the feed end (41) of the furnace shaft (40) is an alternatingly operatable, vertically to each other working, double thrust-punch device comprising a compression device (52) and thrust punch (53).
14. Apparatus according to Claim 12, characterised in that the melt-bath container (44), which adjoins in a gastight seal (48) the output end (42) of the elongatedly positioned pyrolysis chamber, is arranged below the furnace shaft (40).
15. Apparatus according to Claims 12 to 14, characterised in that the pyrolysis chamber cross-section is at the feed end (41) provided with cross-sectional apportioning means (56) for regulating the discharge or pyrolysis material.
16. Apparatus according to Claims 12 ato 15, characterised in that the cross-section of the pyrolysis chamber is arranged to be rectangular.

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