WO2000017288A1 - Method and device for processing waste products and recrements - Google Patents

Abstract

The invention applies to the paper industry and relates to the processing of recrements resulting from paper production. The aim of the invention is to preserve the used materials while having a low environmental impact. To this end, a method is provided in which the accrued materials are separated, selected, preheated and/or dried. Afterwards, they are subjected to a thermal decomposition, whereby the thermal decomposition is carried out under substoichiometric conditions, air is supplied to the process, and an open flame is realized. The invention also uses a device containing at least one receptacle which can be cooled and which internally comprises a conveying device and a parting wall with a sluice-like opening. In addition, the receptacle also comprises a device which is situated at the discharge side of the receptacle and which is provided for producing an open flame and has a device which is located under the area of the thermal decomposition and which is provided for supplying air in a dosed manner.

Description

 Process and device for processing waste products and waste materials

Technical field

The invention relates to the fields of the paper industry, waste management and mechanical engineering and relates to a method and an apparatus for processing waste products and waste materials, in particular waste materials that occur in the paper industry and are to be used as widely as possible.

State of the art

When processing waste paper in the recycling process, residues remain after the mechanical sludge has been slurried. These residues can contain clumped paper, cardboard residues, plastic pieces, wood residues, metal parts and more in different amounts, concentrations and types. The entirety of these residues are called rejects. These rejects are generally stored in a hazardous waste landfill after exiting the sludge process and, if necessary, after intermediate storage, during which gravimetric dewatering can take place.

At this point in time, these rejects contain an average of 50% water, which can occur as surface water and also as absorbed water in the paper and wood content.

Various methods and devices have already been known or described which include the recycling and in particular thermal treatment of waste, residues and also rejects.

According to DE 41 39 512 A1, a method for the thermal utilization of waste materials is known. The waste materials are household waste, plastic-containing industrial waste, paint residues, old tires, shredder light goods from car recycling or waste contaminated with oils. According to this process, these waste materials are subjected to a combination of known process steps, such as pyrolysis, comminution, classification, gasification and gas purification, without expensive pretreatments. On the one hand, this process is intended to generate a clean, versatile gas and energy-efficient gas and, on the other hand, to produce purely mineral, solid residues that are resistant to elution, usable or easy to deposit, and at the same time to exclude toxic pollution to the environment.

Furthermore, according to DE 44 41 423, a method and a device are known which are used to obtain usable gas from waste by pyrolysis. In this process, the shredded waste is placed in a gas-tight pyrolysis drum, in which the pyrolysis gas is generated and the pyrolysis residue is separated off. The pyrolysis gas is split into a cracked gas in a gas converter with the supply of air and in the presence of a glowing coke bed. The heat required for pyrolysis is transferred by a gas in direct contact with the material to be pyrolyzed. A partial flow of this gas is the cracked gas emerging from the gas converter.

A method for recycling a starting material according to DE 43 34 544 is also known. In this method, the starting material made of polymeric or other packaging material with or without content residues, which are vaporizable or not or pyrolyzable or not, is brought into a reaction space. In this reaction space, the carbonizable components are carbonized and the pyrolyzable components are pyrolyzed, the resulting gases being used as energy sources for firing and the residues being removed for further treatment.

According to DE 42 09 549, a process for the thermal treatment of residues is known, for example for the separation and recycling of metal compounds with organic components by means of a combination of pyrolysis and gasification. According to this method, the residues are separated and broken down into a gas and a solid phase by means of pyrolysis at 300 to 700 ° C. Existing usable products are separated from the solid phase and the remaining substances are gasified together with the gas phase at temperatures> 1300 ° C with oxygen-enriched air or oxygen to fuel gas.

A method for removing fissile impurities from a pyrolysis gas is also known from DE 36 32 105. Thereafter, the pyrolysis gas, which is formed in the pyrolysis of a carbon and / or hydrocarbon-containing material, is simultaneously fed to a reaction chamber with a gas heated in a plasma generator and the impurities are split off there, so that the gas can now be fed directly to the consumer.

Also known from DE 38 26 520 A1 is a process for the pyrolysis of sewage sludge in an externally heated fixed reactor with an internally mounted transport device, in which the pyrolysis is a controllable, spatially and temporally separate process in several stages of drying, heating to decomposition temperature, pyrolysis is carried out in several temperature ranges and recycling of the pyrolysis residues as fuel.

The first stage is the dewatering of the sewage sludge, the second stage the heating of the dried products to 200 - 250 ° C, the third stage is the thermal decomposition of the sewage sludge to pyrolysis gases and a carbonaceous residue at 251 to 700 ° C, preferably at 300 - 500 ° C, and the fourth stage is the combustion of the pyrolysis gases and the use of hot gas to heat the reactor in separate heating zones according to stages 1, 2 and 3.

A disadvantage of all these processes is compliance with high safety standards, since the process steps used, in particular pyrolysis and gasification, have to be carried out partly in the absence of air and at high temperatures. Presentation of the invention

The object of the invention is to obtain as complete a processing of the waste products and waste materials as possible with the least possible environmental pollution, using a device that is easier to handle and easier to regulate.

The solution according to the invention makes it possible to almost completely process waste products and waste materials in an environmentally friendly manner and thereby obtain energy which can be used in part to maintain the method according to the invention. However, it can also be used for other energy-intensive processes.

The operation of the device according to the invention is as follows using the method according to the invention.

Any waste products and waste materials from a wide variety of areas, for example from the paper industry (rejects) or from the leather industry or household or special waste, are transported. These products and substances are very inhomogeneous, composed of a wide variety of inorganic and organic substances and often pressed or compressed together.

For this reason, the first process step and device component according to the invention are necessary for dividing these products and substances. This can be done by devices known per se in the form of shredders, shredders or chaffing devices.

After the resulting products and substances have been divided, a selection is carried out according to the invention. This selection aims in particular at separation according to metallic and non-metallic substances. All metallic substances can be recycled. This selection is advantageously carried out by means of a magnet for ferrous metals and an eddy current separator for non-ferrous metals. The waste products and waste materials thus prepared are then either fed to a separate device for preheating and / or drying them, or are fed to the container via a device in which the thermal decomposition is carried out.

In the first case, the separated and selected waste products and waste materials are preheated and / or dried in a separate device, which is advantageously a preheater that receives the required energy from the process and at the same time serves as a material buffer. From this device the preheated and / or dried material is then brought to the container for the thermal decomposition via a device.

The divided and selected and, if necessary, preheated and / or dried material reaches the container via a lock-type feed.

In the container, which can be cooled, there is a transport device, with the aid of which the introduced goods are transported in the longitudinal direction of the container to the discharge opening. Such a transport device must withstand the temperatures prevailing inside the container and be fully functional. Such a transport device is advantageously a conveyor belt or a screw conveyor or a cellular wheel sluice.

In the area in which the material is now introduced, heat is supplied, advantageously in the form of already cooled down gaseous decomposition products of the thermal decomposition from the area for thermal decomposition in the container arranged in the direction of the discharge opening. In this area, the introduced goods are brought to a temperature of advantageously approximately 150-200 ° C. or are kept at this temperature. At the end of this area in the container there is a partition across the entire cross section of the container with a lock-like opening. In the upper part of this container section there is a device for removing the gaseous decomposition products through which the gases for heating or maintaining the temperature of the introduced goods are removed. The preheated material is transported through the lock-like opening in the partition into the area of the container in which the thermal decomposition takes place

When the process is started up, a kind of ember bed of glowing, thermally decomposed waste products and waste materials is generated in this area of the container by means of energy supply, which is fed again and again by the preheated material which is subsequently transported to it.This ember bed is also transported further in the direction of the discharge opening and then through the discharge like discharge opening These solid decomposition products are of a coke-like nature

The embers are maintained in this ember bed by the subsequent supply of material to be decomposed and by the supply of oxygen or air. Below the ember bed there is advantageously a device for the metered supply of air or oxygen over the entire length of the area for the thermal decomposition

Controlled thermal decomposition is achieved through the targeted and metered supply of air or oxygen in the area of thermal decomposition, which can be controlled very precisely with regard to its temperature control via the amount of supplied air or oxygen. The more air or oxygen is supplied, the more so the temperature is higher in the area of thermal decomposition of the container

According to the invention, thermal decomposition is a controlled process between

Pyrolysis and combustion of the goods brought in

According to the prior art, pyrolysis is a process in which substances are pyrolyzed in a container with the exclusion of air at temperatures around 700 ° C. The container is heated from the outside

In contrast to pyrolysis, substances can in principle also be gasified and / or burned according to the prior art

According to the invention, however, there is no complete pyrolysis and no complete combustion of the introduced material since only in substoichiometric amount of air or oxygen is fed to the process and in any case free oxygen completely combines with substances capable of oxidation. This process according to the invention is referred to as thermolysis. This makes it possible not to have to run the process under absolutely gas-tight conditions, which results in a considerably less expensive device leads the safety requirements are no longer so high

After starting the process, the thermal decomposition takes place with the release of energy

In the area of thermal decomposition in the container, temperatures up to 900 ° C. are controllably generated and maintained. Temperatures between 400 and 800 ° C. are advantageously set

In the case of thermal decomposition, in addition to the solid decomposition products, gaseous ones are also produced. These are discharged from the container via a device for removing these gaseous decomposition products. The gaseous decomposition products, which are hot up to 900 ° C., are passed through a device for heat removal and / or filtering. This device can advantageously be used or be more than one heat exchanger and / or one or more gas scrubbers In these devices, thermal energy is extracted from the gaseous decomposition products and their temperature is cooled down to advantageously around 200 ° C. These cooled gaseous decomposition products can be wholly or partly the container in the area of the supply of the divided and selected waste products and waste materials are fed or a separate device for preheating / drying the divided and selected waste products and waste materials. The remaining rest is further cooled down and ge optionally filtered and then released to the environment, advantageously via a further device for the combustion of these gaseous decomposition products in the form of a flame

The solid decomposition products can be fed to a further thermal decomposition. The further thermal decomposition takes place with the addition of water vapor and / or preheated air Decomposition products are used after their cooling and filtering to introduce energy into the process

The invention is explained in more detail using an exemplary embodiment

The device according to the invention consists of tearing rollers to which a conveyor belt with a magnet is connected.A drying tower with a capacity of 30 m ^{3 is also} present and a pneumatic conveyor system to the drying tower and from the drying tower to the container is a conveyor belt.A cylindrical container with the dimensions length 8000 mm, inside diameter 1600 mm has a sluice in the upper left area, through which the preheated substances fall into the container in portions. The container also has a tubular gas supply in the lower left part. After 5000 mm long, a partition is installed inside the container over the entire cross-section. which has an opening in the lower area with the dimensions 200 x 500 mm. Inside the entire length of the container there is a Ruhrwerk with transport wings with an axis arranged centrally to the container. This Ruhrwerk with transport wings is driven by a motor that is outside the es container is arranged In the upper area of the container in front of the partition wall in the direction of the discharge opening, a tubular gas discharge opening with pipes is arranged

A supply of air is located below the area of the container after the partition and a burner is arranged in the same area above it. The discharge opening is provided with a lock and leads into a cylindrical container for post-treatment

A gas extraction opening is arranged above the area of the container after the partition. From there, a pipeline leads to two heat exchangers and on to the gas supply in the lower left part of the container. From the upper left part of the container, a pipeline leads to a gas scrubber in which an air vent is installed further pipeline leads from that first heat exchanger to the device for supplying air and a pipeline leads from the second heat exchanger to the drying tower.

Waste products and waste materials from the paper industry are used, the following

Have composition.

Paper and cardboard remains, lumpy, 1.0 to 3.0 cm edge length,

Pieces of wood, mechanically broken open, partly fibrous surface, 0.5 to 5 cm

Edge length,

PE film and plastic residues, sometimes in lumps, up to 10 cm ² ,

Pieces of rubber, as strips and cords, tangled, 0.5 to 3.0 cm,

Textile remnants, shredded as pieces, 1 cm ² to 5 cm ² ,

Ferrous metal, as pieces of wire, sheet metal strips and shredded in shredded form,

0.5 to 3 mm edge length or diameter,

Aluminum foil, as pieces or crumpled up to 2cm ball diameter,

Tinplate, beverage cans, crushed.

The gross weight of these products and fabrics is approx. 0.35 kg / dm ³ .

The water content is approximately 40%.

These products and fabrics are cut with tear rollers. The throughput is 5 t / h. The cut goods are then processed with a magnet and the selected metal parts removed. The goods are then transported to a drying tower by means of a pneumatic conveyor system, in which they are heated to approx. 80 ° C and the water is extracted. The residence time in the drying tower is approximately 1.5 hours.

The dried goods are then continuously conveyed into the container in portions via conveyor belts and the lock in the upper left part of the container. In the container, the material is conveyed with the agitator in the direction of the discharge opening at a speed of 5 - 7 rpm. The remaining moisture is removed. The material then reaches the partition and is transported through the lock-like opening in the partition into the area of thermal decomposition. In this area, after starting the process, there is a bed of embers that is fed by the material that is conveyed in and that the embers are maintained by the heated air supplied (3.2 m3 / h). The introduced material is thermally decomposed and the solid decomposition products in The form of 95 - 98% crystalline carbon, the so-called pyrolysis coke, is discharged from the discharge opening and subjected to further thermal decomposition

In the area of thermal decomposition, temperatures of approx. 700 ° C prevail after starting the process. To start the process, the temperature is generated by a nozzle burner. Thereafter, thermal decomposition releases energy that is used to maintain the temperature in this area

The resulting gaseous decomposition products are fed from the container via pipes to two heat exchangers and cooled down to a temperature of 200 ° C. This gas is then fed into the left part of the container, where heat is extracted again and it absorbs water vapor and flows through it Good filterahn ch is freed from long-chain hydrocarbons After exiting the left part of the container, it goes through a blower to increase the pressure and from there it is passed into a gas scrubber, where all unwanted contaminants are removed from the gas. Afterwards, it is passed on for further use or for flaring The air heated in the heat exchangers is then partly discharged to the drying tower of the device for the metered supply of air and partly to the atmosphere

Claims

claims 1 Process for the processing of waste products and waste materials, in which the resulting products or substances are divided and selected, in particular metallic components being wholly or partly removed, then preheated and / or dried, then subjected to thermal decomposition, the thermal decomposition carried out at temperatures up to 900 ° C with direct energy input into the process space and under substochiometric conditions and the process is supplied with an amount of up to 5 m ³ / h of air or oxygen and an open flame is directly implemented in the area of thermal decomposition, and the resulting decomposition products are either fed to a further subsequent thermal decomposition or to a treatment, energy being extracted from the substances during the treatment and at least some of the energy obtained being used for the thermal decomposition of the waste products and waste materials becomes 2 The method of claim 1, wherein the waste products and waste materials are mechanically divided 3 The method according to claim 1, in which the waste products and waste materials obtained are selected immediately after being broken down with regard to metallic and non-metallic components, only the non-metallic components being fed to the further processing of the waste products and waste materials 4 The method of claim 1, wherein the selected waste products and waste materials are preheated to a temperature of 150 to 200 ° C 5 The method of claim 1, wherein the selected waste products and waste materials are dried at a temperature of 150 to 200 ° C. 6. The method according to claim 4 or 5, wherein the preheating and / or drying of the selected waste products and waste materials is carried out in a separate device independently of the device for the thermal decomposition 7. The method according to claim 4 or 5, wherein the preheating and / or drying of the selected waste products and waste materials is carried out in a part of the device for thermal decomposition. 8. The method of claim 1, wherein the thermal decomposition of the selected and preheated / dried waste products and waste materials is carried out in a part of the thermal decomposition device. 9. The method according to claim 1, wherein the thermal decomposition of the selected and preheated / dried waste products and waste materials is carried out at temperatures between 400 and 800 ° C. 10. The method according to claim 1, wherein the thermal decomposition of the selected and preheated / dried waste products and waste materials is carried out under substoichiometric conditions, the decomposition temperature being controlled via the amount of oxygen supplied for the thermal decomposition. 11. The method according to claim 1, wherein the thermal decomposition of the selected and preheated / dried waste products and waste materials is carried out with the addition of 0.5 - 4 m ³ / h of air or oxygen. 12. The method according to claim 1, wherein the resulting gaseous decomposition products are subjected to a treatment. 13. The method according to claim 12, wherein the treatment is carried out with energy removal of the decomposition products, the gaseous decomposition products being cooled down in a heat exchanger. 14. The method according to claim 12, wherein the gaseous decomposition products are processed in a gas scrub with heat. 15. The method according to claim 12, in which the gaseous decomposition products are prepared by completely or partially removing the undesired constituents, in particular entrained solid constituents. 16. The method of claim 15, wherein the entrained solid components in the gaseous decomposition products are removed. 17. The method according to claim 15, wherein the acidic components of the gaseous decomposition products are removed by neutralization. 18. The method according to claim 15, in which the water vapor as a component of the gaseous decomposition products in the gas scrubbing is removed by cooling the washing water and condensing. 19. The method according to claim 12, wherein the gaseous decomposition products are used for further processing after processing. 20. The method according to claim 12, wherein the gaseous decomposition products are burned in an environmentally friendly manner. 21. The method according to claim 1, in which the solid decomposition products of the thermal decomposition are subjected to a further thermal decomposition under the conditions of the addition of water vapor and / or a substoichiometric addition of air. 22. The method according to claim 1, wherein the solid decomposition products are supplied for further use or deposited. 23. Device for the processing of waste products and waste materials, comprising a device for dividing the waste products and waste materials and a device for selecting the waste products and waste materials and further comprising at least one coolable container, which has a transport device and a partition wall with a lock-like opening inside furthermore, at one end of the container there is a lock-like feed for the waste products and waste materials and at the opposite end of the container there is a lock-like discharge opening for the solid decomposition products and furthermore at this end of the container a device for generating an open flame is arranged , wherein the open flame extends into the container, and also at this end of the container completely or partially below the area of thermal decomposition, a device for the metered supply of air or oxygen is arranged, which enables a direct supply of air or oxygen into the container , and in the upper part of the range of the thermal decomposition in the container a device for removing the gaseous decomposition products is arranged, which completely or via at least one device for heat removal and / or filtering the gaseous decomposition products is partially led to further use or to the part of the container in which the lock-type feed for the waste products and waste materials is arranged and a further device for removing the gaseous cooled and / or filtered decomposition products from the area of the container is arranged in front of the partition 24. The apparatus of claim 23, wherein the coolable container is tubular. 25. The apparatus of claim 23, wherein the coolable container is double-walled. 26. The apparatus of claim 23, wherein a transport device in the form of a conveyor belt or a screw conveyor or a cellular wheel sluice is arranged in the interior of the container. 27. The apparatus of claim 23, wherein the container is arranged by a partition in a larger area from the lock-like feeder and in a smaller area for thermal decomposition in the direction of the lock-like discharge opening. 28. The apparatus of claim 23, wherein the open flame generating device is a burner. 29. The device according to claim 23, wherein the device for the meterable supply of air or oxygen is arranged below the area for the thermal decomposition of the waste products and waste materials and is guided at least over the length of the area for the thermal decomposition. 30. The device according to claim 23, wherein the device for the meterable supply of air or oxygen warms air wholly or partly from the device for removing the gaseous decomposition products from the region of the container in which the thermal decomposition takes place. 31. The apparatus of claim 23, wherein the heat extraction device is at least one heat exchanger. 32. Apparatus according to claim 23, wherein the device for washing the gaseous decomposition products is a gas scrubber. 33. Apparatus according to claim 24, in which a device for preheating and / or drying the divided and selected waste products and waste materials is present. 34. Apparatus according to claim 24, wherein a device for burning the resulting gaseous decomposition products is present. 35. Apparatus according to claim 24, in which a device for the thermal aftertreatment of the solid decomposition products obtained is present. 36. The apparatus of claim 24, wherein a device for storing the resulting solid decomposition products is present.