DE10132843A1 - Steel-making or refuse incineration-dust conversion into inert formed mass for disposal comprises combining with pre-heated binding agent in extruder for discharge in pre-determined form - Google Patents

Abstract

Following the removal by filtration of dust particles from steel making or refuse incineration, the dust particles are conditioned by combination with a binding agent in a pre-determined ratio and are surrendered to an extruder (12). The components are mixed in the extruder to a plastic mass and extruded in a pre-determined form. The binding agent is melted within the extruder and the dust is then admixed. Prior to admixture, the dust is heated to a temperature above the melting point and below the break-down temperature of the binding agent, preferably in the range 100-250 deg C. Prior to the extrusion process, the mass within the extruder is cooled to between 50 and 250 deg C. The proportion of dust to plastic binding agent is 5-95%. The plastic binding agent further incorporates conditioning additives, e.g. alloy and/or ashes derived from steel manufacturing processes. An Independent claim is also included for a steel-making process and assembly.

Description

The invention relates to a method for conditioning of dusts, in particular for the conditioning of Filter dust. The invention further relates to a method for Operation of an incinerator, a process for Metal production and a plant for performing the inventive method.

When operating incinerators, especially when Operation of waste incineration plants and Incineration plants of fossil-fired power plants, as well as in the iron and steelmaking create flue gases with high Shares in fine dusts, very fine dusts, aerosols and other pollutants and harmful gases. So that the flue gases can be emitted, the Flue gases cleaned and those contained in them Pollutants and dusts separated. The cleaning of the Flue gases and fine dust subsequently disposed of at considerable cost or to be processed further.

The object of the invention is a method for Conditioning of dusts, a method of operating Incineration plants, a process for metal production or to specify a system for the conditioning of dusts, through its or its use the storage, the Transport and further processing of the dusts is simplified.

According to a first aspect of the invention, the object through a process for conditioning dusts solved that the dusts to be conditioned and a Binder in a predetermined mixing ratio Extruders are fed that are to be conditioned Dust in the extruder mixed with the binder and added a plastic mass are processed and that the plastic mass formed into shaped elements after mixing becomes.

According to a further aspect of the invention, the Task through a method of operating Incineration plants according to claim 10, by a method for Metal production according to claim 13 and by a plant for performing a method of conditioning Dusts solved according to claim 16.

Advantageous further developments of the invention result from the respective dependent claims.

In the method according to the invention, the dusts for example from the flue gases of an incineration plant or melting plant were filtered out in one predetermined mixing ratio mixed with a binder. To For this purpose, the dusts to be conditioned and the Binder fed to an extruder. The dusts and that Binders can either be separated from each other or can also be introduced together into the extruder.

The extruder used to condition the dusts has a mixing zone in which the to conditioning dusts with the binder to a plastic Bulk processed. The dusts are mixed with the Binder mixed so that a plastic mass is created in which the dusts are bound in the binder. The plastic mass then becomes shaped elements shaped, for example into rod material, briquettes, Granules and the like, the shape of the shaped element from the subsequent further processing step depends.

By incorporating the dusts into the binders achieved that dust formation during storage and transport of the dust is prevented. Furthermore is a further processing of the in the form elements bound dusts simplified. So the dusts can either safely deposited as form elements or one Further processing, for example a new incineration, be fed.

In order to prevent the development of dust during the conditioning of the To keep dusts as low as possible, one preferred process variant of the process for Conditioning of dusts suggested the binder first melt in the extruder and only then the dusts to feed the melted binder. To this Way is achieved that the dusts continuously according to the specified mixing ratio with the melted binders are mixed, the dust immediately surrounded by the binder when mixing and dust formation during mixing is prevented.

In this method variant, it is also proposed that the binder and the dust when mixing in the extruder to heat a predetermined temperature. That temperature is above the melting temperature of the Binder, so that the binder melted evenly on the other hand, while below the Decomposition temperature of the binder is kept to a Destruction of the matrix formed by the binder prevent. Especially when using plastic ones Binders have proven to be beneficial Mixing temperature in a range of about 100 to Maintain 250 ° C.

Furthermore, this method variant suggested the plastic warmed during mixing Cool mass to reduce the viscosity of the plastic mass to increase this to the one you want Form elements can be molded.

The proportion of dusts in the plastic mass is preferably in a range from 5 to 95%. The maximum permissible proportion of dusts in the plastic Mass primarily limited by the extent to which from the molded plastic molded elements after cooling keep their shape and not break or fall apart.

In a preferred further process variant suggested the binder before or after mixing with to add additives to the dusts to be conditioned. With the help of these additives, the strength of the shaped elements to be formed are increased. simultaneously there is the possibility, with appropriate selection of the Additives the molded form elements of a targeted To supply further processing.

So it is particularly suggested as additives Alloy and / or slag formers for metal production to use. The one with the alloy and / or Slag formers offset form elements from binder and Dusts can then be fed to a melting process. Due to the known proportion of alloy and / or Slag formers in the form elements is this way a very exact dosage of the alloying agents at Melting process possible. At the same time, the Melting process again supplied dusts either in the Metal melt dissolved or in the slag Metal melt incorporated.

Thermoplastics in particular are used as binders, those at higher temperatures, for example in one Melt range from 100 to 250 ° C, but not decompose. Alternatively or together with the thermoplastics thermosets can also be used as binders, which become plasticizable at higher temperatures and at low temperatures in particular by a high dimensional stability.

Instead of thermoplastic or thermosetting plastics, or natural resins or plastic waste as binders be used. When using multi-component The various components of the binder can Binder to the extruder at different times be performed.

As an extruder for mixing the dusts to be conditioned with the binder in particular Double shaft extruder used, which is characterized by a particularly good Mixing the dusts with the binder. A twin-screw extruder is particularly suitable for this purpose, whose extruder shafts rotate in opposite directions. Alternative is it is also conceivable to use single-screw or multi-screw extruders use co-rotating extruder shafts.

According to a second aspect of the invention there is a method proposed to operate an incinerator. So arise especially when operating a Waste incinerator or when operating a fossil incinerator fired power plant flue gases, which have a high proportion fine dusts, very fine dusts, aerosols and others Contain pollutants. According to the invention, it is proposed filter out the dust contained in the flue gas and according to the previously described procedure condition and incorporate in form elements in binders. In the inventive method for operating the Incinerator is also proposed this Form elements in which the dusts are contained, at least partly the incinerator for re-incineration supply. As an alternative or in addition, at least one part can the dusts can also be recycled. For example, the dusts often contain flammable substances Ingredients also combustible carbon compounds and the like Substances only in the previous combustion process were partially burned. By returning the Conditioned dusts are achieved, especially those combustible dusts are fed back into the combustion process be, reducing the efficiency of the incinerator based on the total fuel used increased becomes.

In particular, it is proposed that the invention Process for operating a waste incineration plant use, the shaped elements in the incinerator waste materials to be treated thermally. By returning the conditioned dusts to the Incinerator is particularly an increased Separation of non-combustible dusts into the slag has been achieved, which in particular pollutes substances which are harmful to the environment Combustion occurs in which slag is bound.

In a preferred variant of the method of operation an incinerator is proposed as Binder, especially plastic waste from thermoplastics and / or to use thermosets. This will achieved the plastic waste that otherwise than Fuels in waste incineration plants or in fossil fired power plants are used, an additional Perform function, namely that of the previous one Combustion generated dust to bind so that the Combustion process can be fed again. The Plastic waste in the binder preferably in a range from 2 to 100%. The rest of the share in the binder consists of, for example prepared plastics, synthetic resins, natural resins and the like.

According to a third aspect of the invention, a Process for metal production proposed in which the dusts be conditioned in the manner according to the invention.

So it is known that in iron and steel making, especially in blast furnaces, in arc and Induction furnaces, in metal processing and in converters at Blow out the molten metal with air and oxygen (Linz / Donawitz process) large amounts of flue gases are generated which with a high proportion of fine dusts, very fine dusts, Aerosols and other pollutants and pollutant gases are burdened. The resulting dusts and Fine dust is filtered out using known filter processes and usually landfilled or otherwise Subsequent treatment.

In the method for metal production according to the invention are now filtered out when cleaning the flue gas Dusts conditioned and in form elements in binders involved. Then the shaped elements at least partially returned to the melting process.

Due to the high temperatures during the Melting process prevail in metal production, is a Most of the mixture, which consists of flammable substances and Dusts exist, while not thermally processed flammable components in the during the process resulting slag or melt can be integrated.

In a preferred variant of the method for Metal fabrication is suggested before or before the binder after mixing with the dusts to be conditioned additional alloy or slag formers for the Manufacture of metal alloys. The form elements in this variant of the method not only serve as Carrier for the dusts to be conditioned, but also as a carrier for the alloying agents. By accordingly setting the proportions of the alloying agents in the finished form elements made of binder, dust and Alloy or slag formers become very precise Dosage of the alloy or slag formers during the Metal production possible. The proportion of alloying agents in the finished form elements lies with this Process variant preferably at least 5% in the finished Form elements, however, should not account for 75% exceed.

In a preferred procedure this Process variant is proposed, the binder, the dust and the alloy or slag formers in the extruder Pressure, however, before cooling and molding the form elements to mix with each other. To a particularly homogeneous Mixing the binder with the dusts and Reaching alloy or slag formers will also be suggested the temperature when mixing in one area keep from 100 to 300 ° C.

To perform a procedure for conditioning A dust system is proposed, such as that in sibling claim 16 is defined. In this facility is According to the invention, an extruder is provided which has a mixing zone for mixing the dusts to be conditioned with a Has binder to a plastic mass. Of Another is at the plant at the exit end of the extruder Molding tool provided with which the plastic mass in the corresponding form elements can be reshaped. The Use of an extruder according to the invention in the system for Conditioning dust has the particular advantage of that the extruder housing is self-contained Process room forms, which when mixing the dust with an unwanted dust development at least to the binder can be largely prevented. Furthermore, the Use of the extruder has the advantage of being very precise Procedure during the mixing of the conditioning dusts with the binder is possible.

In a preferred embodiment of the invention Plant, the extruder has a melting zone that the Mixing zone is viewed upstream in the direction of extrusion. This melting zone of the extruder is used for melting of the binder, so that the binder is already in the melted state reaches the mixing zone. To this Way is achieved that the dusts to be conditioned incorporated into the already melted binder be, which creates dust when mixing the Dusts with the binder are prevented particularly effectively.

In a further development of this embodiment is also proposed between the melting zone and the To provide an intermediate separation device in the mixing zone, with the impurities from the melted Binder can be removed. This is especially so advantageous if the binder, for example Contains plastic waste that may be undesirable Contain impurities.

Furthermore, in a preferred embodiment, the proposed system between the Mixing zone and the exit end of the extruder another Provide mixing zone in which the mixture of dusts and Binder other additives can be added.

The system according to the invention is preferably in a Incinerator used, the plant a Feeding device with which the smoke gases from the Combustion process filtered dust the extruder are feedable. That the extruder in the extrusion direction The following mold can in turn be used with the Incinerator can be connected so that the system is one in itself forms a closed cycle. This ensures that conditioned at least part of the filtered dusts and is fed to the combustion process again.

In an alternative embodiment, the plant in a melting plant used for metal production. For this purpose, the system is equipped with a feed device equipped with the from the during the melting process resulting smoke gases filtered out dust the extruder are feedable. The extruder in the direction of extrusion The following molding tool is in turn with the melting furnace Melting system connectable, so that this too Embodiment is a closed circuit is formed. The Use of the system according to the invention for the Metal production is particularly advantageous when Production of the shaped elements by the extruder Dusts and binders formed form elements in addition Alloying agents are added, which are used for a Metal finishing is required during the melting process.

The invention is described below with reference to two Exemplary embodiments explained in more detail. In it show:

Figure 1 is a schematic representation of a first embodiment of a system for conditioning dusts. and

Fig. 2 is a schematic representation of a second embodiment of a system for conditioning dusts.

Fig. 1 shows a schematic representation of a system 10 for the conditioning of dusts. Plant 10 is used in particular in waste incineration plants and in combustion plants of fossil-fired power plants. It is also possible to use the system 10 in a smelting system for metal production.

The system 10 has an extruder 12 which has a first feed device 16 at its inlet end 14 shown on the left in FIG. 1, through which, as will be explained in detail later, a binder is conveyed into the extruder 12 . Upstream of the first feed device 16 is a pre-shredder 18 and a first separating device 20 arranged between the pre-shredder 18 and the first feed device 16 . With the help of the pre-shredder 18 , the binder raw material, for example plastic parts, plastic waste and the like, is shredded. The comminuted binders are then fed to the first separating device 20 , with which any impurities contained in the comminuted binder raw material are removed.

In the area of the first feed device 16 , a melting zone 22 adjoins the inlet end 14 of the extruder 12 and can be heated by an externally arranged first heating device 24 . A first extruder shaft 26 is provided in the first melting zone 22 , with which the binder is fed in the direction of a second separating device 28 arranged downstream of the melting zone. After the binder raw material has been comminuted by the pre-shredder 18 and cleaned by the first separation device 20 , the binder raw material reaches the melting zone 22 of the extruder 12 , is melted in this by the first heating device 24 and at the same time is evened out by the extruder shaft 26 . The binder melted in this way is then pressed by the extruder shaft 26 through the second separating device 28 , impurities possibly still contained in the melted binder being removed by the second separating device 28 .

The second separation device 28 opens into a mixing zone 30 of the extruder 12 , which in turn merges into a cooling zone 32 . Two extruder shafts 34 are provided in the mixing zone 30 and the cooling zone 32 and are operated in opposite directions in the present case. Near the second separation device 28 , a second feed device 36 also opens into the mixing zone 30 , through which dusts to be conditioned enter the extruder 12 . Following the second feed device 36 , a second heating device 38 is provided on the mixing zone 30 , with which the mixing zone 30 can be heated to a desired operating temperature. The cooling zone 32 is equipped with a cooling device 40 which is arranged adjacent to the heating device 38 and with which the cooling zone 32 can be cooled to a desired temperature.

At the outlet end 42 of the extruder 12 , which directly adjoins the cooling zone 32 , a molding tool 44 is provided, which is equipped with a cutting device 46 arranged downstream in the direction of extrusion.

If the system 10 is now used in a combustion system, for example a waste incineration system or a combustion system of a fossil-fueled power plant, the second feed device 36 , through which the dusts to be conditioned enter the extruder 12 , is connected to the flue gas cleaning system of the combustion system, in which the Dusts contained in flue gas and very fine dusts from which flue gas is filtered.

The molding tool 44 of the extruder 12 can be connected to the combustion system by means of a correspondingly designed transport device, so that the molding elements formed by the molding tool 44 from binder and dusts can at least partially be fed to the combustion system.

If, on the other hand, the system 10 is used in a smelting system for metal production, the second feed device 36 is connected to the flue gas cleaning system of the smelting system, while the molding tool 44 can be connected to the smelting system.

The functioning of the system 10 is explained in more detail below.

The dusts filtered out from the flue gases are conveyed into the extruder 12 by the second feed device 36 . At the same time, binder raw materials, for example plastic granules, plastic waste and the like, are crushed by the pre-shredder 18 , cleaned by the first separating device 20 and transported through the first feed device 16 into the melting zone 22 of the extruder 12 . In the melting zone 22 , the binder raw materials are melted, homogenized by the extruder shaft 26 and finally conveyed through the second separating device 28 into the mixing zone 30 of the extruder 12 .

In the likewise heated mixing zone 30 , the melted binder is mixed with the dusts supplied by the second feed device 36 under pressure, the temperature in the mixing zone 30 being in a range from 100 to 250.degree. In the mixing zone 30 , the melted binder and the dusts are processed by the two extruder shafts 34 operated in opposite directions to a plastic mass which is then fed to the cooling zone 32 . The proportion of dusts in the plastic mass is in a range between 5 and 95%.

After the plastic mass has been mixed, it is preferably cooled in the cooling zone 32 to a temperature in a range from 50 to 250 ° C. and pressed by the extruder shafts 34 through the molding tool 44 . With the help of the molding tool 44 , profiles are produced from the plastic mass, which are then shortened to the desired length to defined shaped elements with the aid of the cutting device 46 . After curing, the shaped elements can either be transported away for further processing or storage, or at least partially returned to the combustion process in the combustion system or the melting process in the melting system.

Fig. 2 shows a schematic representation of a second embodiment of a system 10 a, the structure of which essentially corresponds to the system 10 described above. The only difference of the system 10 a to the previously described system 10 is that is a further feed device 48 provided at the extruder 12, in a mixing zone between the 30a and the cooling zone 32 a provided for further mixing zone 50 opens. The further mixing zone 50 is provided with a further heating device 52 .

Plant 10 a is used in particular in smelting plants for metal production. The mode of operation of the system 10 a essentially corresponds to the mode of operation of the system 10 , wherein, before the cooling of the plastic mass in the cooling zone 32 a of the plastic mass, additional alloy formers, which are required for the melting process, are added to the extruder 12 a. Manganese, nickel, chromium or carbon in powder form, for example, are added as alloying agents.

During operation of the system 10 a, as already explained above with reference to the first exemplary embodiment, the plastic mass is mixed from a meltable binder and the dusts which have been filtered out from the flue gases of the melting process. The plastic mass is then conveyed by the extruder shafts 34 a from the mixing zone 30 a into the further mixing zone 50 , in which the alloying agents are added to the plastic mass.

The further mixing zone 50 is heated by the further heating device 52 to a temperature in a range from 100 to 300 ° C.

The plastic mass mixed with the alloy formers is then transported from the further mixing zone 50 into the cooling zone 32 , in which the plastic mass is cooled to a lower temperature in a range from 50 to 250 ° C., which is favorable for molding. After cooling, the extruder shafts 34 a press the plastic mass through the molding tool 44 and the cutting device 46 , the shaped elements being shaped and cut to the desired shape. The proportion of alloying agents in the shaped elements is in a range from 5 to 75%, depending on the desired alloying effect.

Then the with the alloy formers offset form elements fed to the melting process.

By using the system 10 a it is achieved on the one hand that the dusts and fine dusts generated during the melting process, which are at least partially recyclable, are returned to the melting process and are either burnt or at least partially integrated into the slag of the metal melt. At the same time, the shaped elements serve as dosing agents for adding desired alloy elements, with a very exact dosing of the alloy elements being possible for the melting process.

Claims (21)

1. A method for the conditioning of dusts, in particular for the conditioning of filter dusts, characterized in that
that the dusts to be conditioned and a binder are fed to an extruder ( 12 ) in a predetermined mixing ratio,
that the dusts to be conditioned are mixed in the extruder ( 12 ) with the binder and processed into a plastic mass and
that the plastic mass is shaped into shaped elements after mixing. 2. The method according to claim 1, characterized in that the binder is melted in the extruder ( 12 ) and then the dusts are fed to the melted binder. 3. The method according to claim 2, characterized in that the binder and the dusts when mixing in the extruder ( 12 ) at a temperature above the melting temperature of the binder and below the decomposition temperature of the binder, preferably to a temperature in a range from 100 to 250 ° C, be warmed. 4. The method according to claim 2 or 3, characterized in that the plastic mass in the extruder ( 12 ) before molding, preferably to a temperature in a range from 50 to 250 ° C, is cooled. 5. The method according to any one of claims 1 to 4, characterized, that the proportion of dusts in the plastic mass is in a range from 5 to 95%. 6. The method according to any one of claims 1 to 5, characterized, that the binder before or after mixing with the additives for conditioning dusts become. 7. The method according to claim 6, characterized, that as additives alloy and / or Slag formers, especially alloy and / or Slag formers for steel production become. 8. The method according to any one of claims 1 to 7, characterized, that as a binder thermoplastics and / or thermosets be used. 9. The method according to any one of the preceding claims, characterized in that a double-shaft extruder ( 12 ) is used as the extruder, the extruder shafts of which preferably rotate in opposite directions during operation. 10. Method for operating an incineration plant, in particular for operating a waste incineration plant or for operating the incineration plant of a fossil-fired power plant, in which
smoke gases generated in the incinerator are removed from the incinerator,
dusts contained in the flue gases are filtered out and
the filtered dusts are sent for further processing,
characterized,
that the dusts are conditioned for further processing in accordance with one of the methods according to one of claims 1 to 9 and are incorporated in shaped elements in binders and
that the shaped elements, in which the dusts are contained, are at least partially fed to the incinerator for renewed combustion or recycling. 11. The method according to claim 10, characterized, that the process of operating a Waste incineration plant is used, being in the Incinerator waste materials under the formation of flue gases be processed thermally. 12. The method according to claim 10 or 11, characterized, that the binder is made of plastic waste Contains thermoplastics and / or thermosets, the proportion of Plastic waste in the binder preferably at 2 up to 100%. 13. Process for metal production, in particular for steel production, in which
Metal raw materials are melted in a melting process,
smoke gases generated during melting are removed for cleaning and
when cleaning the flue gases, the dusts contained in them are filtered out and sent for further processing,
characterized,
that the dusts are conditioned for further processing in accordance with one of the methods according to one of claims 1 to 9 and are incorporated in shaped elements in binders and
that the shaped elements in which the dusts are contained are at least partially fed to the melting process. 14. The method according to claim 13, characterized, that the binder before or after mixing with the dusts to be conditioned as Additives Alloy formers for the production of Metal alloys are supplied, the proportion the alloy and / or slag formers in the finished form elements preferably at 5 to 75% lies. 15. The method according to claim 14, characterized in that the binder, the dusts and the alloy and / or slag formers in the extruder ( 12 ) under pressure, preferably at a temperature in a range from 100 to 300 ° C, before cooling and shaping the shaped elements are mixed together. 16. Plant for performing a method for conditioning dusts, in particular for performing the method according to one of claims 1 to 15, characterized by
an extruder ( 12 ) which has a mixing zone ( 30 ) for mixing the dusts to be conditioned with a binder to form a plastic mass and
a molding tool ( 44 ) for the plastic mass, which is provided at the outlet end ( 42 ) of the extruder ( 12 ). 17. Plant according to claim 16, characterized in that
that the extruder has a melting zone ( 22 ) for melting the binder and
that the melting zone ( 22 ) is arranged upstream of the mixing zone ( 30 ) in the direction of extrusion. 18. Plant according to claim 17, characterized in that the extruder ( 12 ) between the melting zone ( 22 ) and the mixing zone ( 30 ) has an intermediate separating device ( 28 ) for separating contaminants from the molten binder. 19. Plant according to claim 16, 17 or 18, characterized in that
that a further mixing zone ( 50 ) is provided on the extruder ( 12 ) between the mixing zone ( 30 ) and the outlet end ( 42 ) and
that the further mixing zone ( 50 ) serves to mix the dusts and the binder with additives. 20. Plant according to one of claims 16 to 19, characterized in that
that the system is used in an incineration plant, in particular in a waste incineration plant or a combustion plant of a fossil-fired power plant,
that a feed device ( 36 ) is provided with which the dusts filtered out from the flue gases of the combustion process can be fed to the extruder ( 12 ), and
that the mold ( 44 ) following the extruder ( 12 ) in the extrusion direction can be connected to the incinerator. 21. Plant according to one of claims 16 to 19, characterized in that
that the plant is used in a smelting plant for metal production,
that a feed device ( 36 ) is provided with which the dusts filtered out from the flue gases produced during the melting process can be fed to the extruder ( 12 ), and
that the mold ( 44 ) following the extruder ( 12 ) in the extrusion direction can be connected to the melting furnace of the melting plant.