WO2024083608A1 - Method for melting and thermally treating solids - Google Patents
Method for melting and thermally treating solids Download PDFInfo
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- WO2024083608A1 WO2024083608A1 PCT/EP2023/078192 EP2023078192W WO2024083608A1 WO 2024083608 A1 WO2024083608 A1 WO 2024083608A1 EP 2023078192 W EP2023078192 W EP 2023078192W WO 2024083608 A1 WO2024083608 A1 WO 2024083608A1
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- WO
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- Prior art keywords
- process gas
- chemical
- gas stream
- melting
- chemical compound
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 78
- 239000007787 solid Substances 0.000 title claims abstract description 22
- 238000002844 melting Methods 0.000 title claims description 33
- 230000008018 melting Effects 0.000 title claims description 33
- 230000008569 process Effects 0.000 claims abstract description 66
- 150000001875 compounds Chemical class 0.000 claims abstract description 22
- 238000010438 heat treatment Methods 0.000 claims abstract description 20
- 229910052729 chemical element Inorganic materials 0.000 claims abstract description 17
- 230000005670 electromagnetic radiation Effects 0.000 claims abstract description 17
- 238000001228 spectrum Methods 0.000 claims abstract description 9
- 238000006243 chemical reaction Methods 0.000 claims abstract description 6
- 230000005281 excited state Effects 0.000 claims abstract description 4
- 150000002500 ions Chemical class 0.000 claims abstract description 4
- 229910052751 metal Inorganic materials 0.000 claims description 22
- 239000002184 metal Substances 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 12
- 150000002430 hydrocarbons Chemical class 0.000 claims description 11
- 230000001939 inductive effect Effects 0.000 claims description 7
- 239000011521 glass Substances 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 229910052708 sodium Inorganic materials 0.000 claims description 3
- 231100000331 toxic Toxicity 0.000 claims description 3
- 230000002588 toxic effect Effects 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 238000002309 gasification Methods 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 150000003839 salts Chemical class 0.000 claims description 2
- 229910052712 strontium Inorganic materials 0.000 claims description 2
- 239000002699 waste material Substances 0.000 claims description 2
- 239000002028 Biomass Substances 0.000 claims 1
- 239000002803 fossil fuel Substances 0.000 claims 1
- 239000012263 liquid product Substances 0.000 claims 1
- 238000001556 precipitation Methods 0.000 claims 1
- -1 residues Substances 0.000 claims 1
- 238000004227 thermal cracking Methods 0.000 claims 1
- 231100000167 toxic agent Toxicity 0.000 claims 1
- 239000007789 gas Substances 0.000 description 59
- 230000005855 radiation Effects 0.000 description 8
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 239000003921 oil Substances 0.000 description 6
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 4
- 239000000155 melt Substances 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 231100001261 hazardous Toxicity 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N Furan Chemical compound C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000000035 biogenic effect Effects 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- NIHNNTQXNPWCJQ-UHFFFAOYSA-N fluorene Chemical compound C1=CC=C2CC3=CC=CC=C3C2=C1 NIHNNTQXNPWCJQ-UHFFFAOYSA-N 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- BBEAQIROQSPTKN-UHFFFAOYSA-N pyrene Chemical compound C1=CC=C2C=CC3=CC=CC4=CC=C1C2=C43 BBEAQIROQSPTKN-UHFFFAOYSA-N 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 229940043430 calcium compound Drugs 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- GVEPBJHOBDJJJI-UHFFFAOYSA-N fluoranthrene Natural products C1=CC(C2=CC=CC=C22)=C3C2=CC=CC3=C1 GVEPBJHOBDJJJI-UHFFFAOYSA-N 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 150000002642 lithium compounds Chemical class 0.000 description 1
- 239000000289 melt material Substances 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 239000010811 mineral waste Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000010955 niobium Substances 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 125000005575 polycyclic aromatic hydrocarbon group Chemical group 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000003870 refractory metal Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 150000003298 rubidium compounds Chemical class 0.000 description 1
- 150000003388 sodium compounds Chemical class 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 150000003438 strontium compounds Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 239000011272 tar condensate Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/04—Crucible or pot furnaces adapted for treating the charge in vacuum or special atmosphere
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/06—Crucible or pot furnaces heated electrically, e.g. induction crucible furnaces with or without any other source of heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/06—Crucible or pot furnaces heated electrically, e.g. induction crucible furnaces with or without any other source of heat
- F27B14/061—Induction furnaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
- F27B14/14—Arrangements of heating devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
- F27B14/14—Arrangements of heating devices
- F27B14/143—Heating of the crucible by convection of combustion gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D11/00—Arrangement of elements for electric heating in or on furnaces
- F27D11/06—Induction heating, i.e. in which the material being heated, or its container or elements embodied therein, form the secondary of a transformer
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
- F27D7/02—Supplying steam, vapour, gases, or liquids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
- F27B2014/085—Preheating of the charge
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D99/00—Subject matter not provided for in other groups of this subclass
- F27D99/0001—Heating elements or systems
- F27D99/0006—Electric heating elements or system
- F27D2099/0015—Induction heating
Definitions
- the invention relates to a method for melting and heat treating solids in a melting furnace or a melting tank as well as to batch and continuous furnaces.
- inductive heating and inductive melting of conductive solids in particular metal as a melting or melting agent.
- the alternating electrical fields that occur in the process cause the melt to stir strongly. This leads to a high level of oxide inclusions in the metal, which has a severe negative impact on the quality of the components produced with the resulting melt.
- Inductively heated melting furnaces are also generally poorly suited to melting coarse lumps of recycled material or cast iron scrap due to unfavorable coupling conditions.
- Electrically resistance-heated furnaces are also known. These usually have only a low output and are therefore generally only suitable for keeping already liquid metal warm by suppressing heat loss.
- the disadvantage is that the heating of the melt can only be achieved with the thermal energy of the process gas flow and with electromagnetic radiation.
- the wavelength spectrum of the electromagnetic radiation also plays a role, since it is known that different wavelengths are absorbed differently by a correspondingly irradiated material and thus contribute to its heating to different degrees.
- a process gas stream emits predominantly short-wave electromagnetic radiation, which impinges on the respective melting material or a melting tank for melting.
- This radiation which mainly contains discrete (blue or green) radiation components, is absorbed with relatively low efficiency by the solids (metals, glasses) or a melting tank, so that the overall efficiency is reduced accordingly.
- At least one hot process gas stream is directed by inductive heating of at least one body through and/or past which the process gas to be heated is directed towards the solid (metal, glass) to be heat-treated or melted or a melting tank or at a distance from its surface, and the heating of the at least one body is achieved with an electrical coil enclosing it, which is connected to an electrical AC voltage source or a pulsed electrical DC voltage source. Only the thermal energy of the process gas stream and the emitted electromagnetic radiation are used to provide process heat.
- At least one chemical element and/or at least one chemical compound is/are introduced into the hot process gas flow and ions are converted into an excited state by the chemical element or chemical compound using the heat of the process gas flow. In combination with the conversion into an excited state, photons are released. Alone or in addition to the excitation of the ions, at least one exothermic chemical reaction can be initiated, the energy of which can additionally heat the process gas flow. In a chemical reaction, as little H2 or CO or CO2 as possible should be released and should not enter the sphere of influence of the material to be heat-treated or to be melting solid or melted material.
- the proportion of electromagnetic radiation directed at the melt with wavelengths of > 575 nm is increased by at least 10%, preferably by at least 30% of the entire spectrum of electromagnetic radiation, with a transition from a discrete to a continuous radiation spectrum (solid-state radiation of carbon) preferably being sought.
- the transition to a continuous spectrum enables the long-wave portion of the electromagnetic radiation to penetrate into the surface of the heat-treated material or into the melt, which enables highly efficient heat input.
- discrete electromagnetic radiation on the other hand, reflection at the surface (solid or melt) dominates, so that a large part of the radiation energy heats the furnace walls and is dissipated unused with the flowing gases by convection.
- the process gas flow should be directed at an angle of between 0° and 20° in relation to the surface of the solid to be heat treated or melted, or of the already melted melt material or the melting tank. However, it can also be directed directly at the solid to be heat treated or melted.
- the solid thus melted with the process gas stream can then be transferred to a melting tank or crucible in the melting furnace.
- Solid (metal or glass) melted in a melting tank can be discharged or removed from it.
- the chemical element used can be Na, Ca, Sr, Li, Rb, Mg or carbon, or the chemical compound used can be at least one chemical compound containing at least one of these chemical elements.
- the alkali metals their salts can be used as chemical compounds.
- the use of sodium or a sodium compound leads to a yellow discoloration of electromagnetic radiation, Ca or a calcium compound to orange-red, Sr or a strontium compound to red, Li or a lithium compound to red and Rb or a rubidium compound also to red as a result of the well-known effect of flame coloration.
- Use of carbon-containing compounds leads to a continuous spectrum with a maximum in the yellow radiation range.
- the at least one chemical element and/or the at least one chemical compound should be supplied in a proportion of greater than 15 vol.%, preferably at least 0.2 vol.% up to a maximum of 10 vol.% in relation to the supplied process gas stream.
- C or a hydrocarbon compound can also be used as a chemical element.
- the supply can be in any possible state of aggregation, i.e. solid, liquid or gaseous. It is also possible to supply a chemical element or a chemical compound in a solvent, i.e. in dissolved form.
- the at least one chemical element or the at least one chemical compound should be fed into an area of the process gas flow in which a minimum temperature of 750 °C is maintained. This is particularly important if the proportion of long-wave electromagnetic radiation from wavelengths of 575 nm and greater is to be achieved by feeding chemical compounds that must react chemically. This is particularly advantageous when feeding hydrocarbon compounds.
- hydrocarbon-containing process gases such as pyrolysis gases, gasification gases or flare gases or other gaseous hydrocarbons such as propane or butane can be used to advantageously influence the spectrum of electromagnetic radiation used for heat treatment and melting.
- gases with sufficiently broad absorption bands can also be used, in particular C-free gases (e.g. NH3) or gas mixtures ("Radiation of gases and vapors").
- Contaminated or toxic hydrocarbon compounds can be, for example, oils that have been used for cooling in transformers. These can also be used thermal oils for heating or cooling high-temperature processes, oil or tar condensates from pyrolysis processes (biogenic residues), solvent waste, biogenic or mineral oils or waste oils.
- the process according to the invention can also be used for safe disposal, since the hazardous components can be chemically converted into non-hazardous or significantly less hazardous components and at the same time can be used to increase the efficiency during heat treatment and melting.
- hydrocarbon compounds can be introduced directly into the hot process gas stream so that sufficiently high temperatures are available for decomposition through chemical reaction(s). This is where the hydrocarbons are completely decomposed and oxidized.
- aromatics such as toluene, benzene, phenol, xylene or furan
- toluene C 7 H S + W 2 4H 2 O + 7CO 2
- polycyclic aromatic hydrocarbons such as naphthalene, fluorene or pyrene
- naphthalene C W H S + 120 2 — 4H 2 O + 10CCU
- the concentration of CO2 released in the flue gas when using these additives is extremely low due to the very low dosage/admixture.
- Chemical elements and chemical compounds which are supplied according to the invention can also be supplied directly or at a distance of preferably a maximum of 50 mm after the process gas stream exits the device.
- the method according to the invention can be carried out with a device as described in DE 10 2022 207 481 A1. Reference is made to the entire disclosure content of this document.
- a process gas flows through a first internally hollow body with a predeterminable volume flow from an inlet to an outlet.
- the first internally hollow body is enclosed or surrounded by at least one electrical coil that is connected to an electrical voltage source with which alternating voltage or a pulsed direct voltage is applied to the electrical coil.
- the at least one electrical coil can be used to heat the first internally hollow body or at least one metal body that is/are arranged inside the first internally hollow body by electrical induction.
- the process gas flows along the inner wall of the first internally hollow body and/or the surface, preferably the outer surface of the at least one metal body, to heat it.
- the first internally hollow body and the at least one metal body are each made of a material whose melting temperature is greater than the maximum temperature of the heated process gas.
- the first internally hollow body and/or the at least one metal body can be made of a steel and/or a refractory metal and/or its alloys - in particular a tantalum, tungsten, niobium or molybdenum-based alloy.
- a base alloy contains at least 50% by mass of the metals mentioned.
- the first internally hollow body can also be made of a refractory material, in particular quartz glass, Al2O3, ZrÜ2 or MgO, which cannot be heated inductively. This is particularly the case if the at least one metal body is arranged in its interior and is heated inductively.
- Several metal bodies can also be arranged as loose fill and/or composite bodies inside the internally hollow body, around which the process gas flows and the process gas is heated along the flow path from the inlet to the outlet.
- the process gas used can be air, but also another gas or gas mixture that may be advantageous for the respective heating process. This particularly includes inert gases that can avoid influencing the elements, materials and objects to be heated.
- the metal body can be designed in the form of a screw, in which the process gas to be heated flows through the turns of the screw, or in the form of a spiral.
- the enlarged surface of the at least one metal body can be used advantageously for heat transfer to the process gas.
- metal bodies with contour elements elevation, depressions
- the at least one electrical coil may enclose a second internally hollow body made of a metal, in addition to the first internally hollow body made of a non-metallic material and the at least one metal body.
- the second internally hollow body can be made of a suitable metal or a suitable ceramic and the first internally hollow body can be made of a non-metallic material, in particular a ceramic material. Both internally hollow bodies should have a sufficiently high melting temperature.
- a fireproof closure element can be arranged at the inlet to the device for the process gas to prevent backflow of the heated process gas. This reduces energy and especially heat losses and the process gas enters exclusively via the appropriately dimensioned inlet.
- the first internally hollow body and the Meta II body, as well as any second internally hollow body, should be tubular.
- the body or bodies could also have other geometries of their internal free cross-sectional areas and/or their surfaces.
- the tubular shape offers advantages in terms of flow technology and because of the relatively large surface area, which contributes to heating the process gas.
- the first internally hollow body can be enclosed by a second and/or a third internally hollow body, so that process gas flows through a gap between the first internally hollow body and the second internally hollow body and/or through a gap between the second internally hollow body and the third internally hollow body in order to heat the process gas in countercurrent or cocurrent to the process gas flow. This enables effective preheating of process gas and utilization of waste heat.
- the temperature of the process gas exiting the outlet can be regulated by adjusting the process gas volume flow and/or the electrical power with which the at least one electrical coil is operated. For this purpose, the temperature of the process gas at the outlet can be determined.
- Process gas flows through the device, exits as hot gas and can be used as a hot gas flare.
- a pipe-in-pipe solution with several hollow bodies inside can achieve thermal insulation and preheating of the process gas, which improves efficiency.
- the at least one chemical element or the at least one chemical compound can be introduced into the interior of a hollow body or into the hot process gas stream after it has exited the device. process gas stream in order to achieve the desired influence according to the invention on the radiation spectrum of the electromagnetic radiation used to heat melting material or a melting tank.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Power Engineering (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
Abstract
According to the method, at least one hot process gas flow is provided by inductively heating at least one body, through which and/or past which process gas to be heated is directed in the direction of solids to be thermally treated or melted, and the at least one body is heated using an electric coil which surrounds the body and is connected to an electric alternating voltage source or an electric direct voltage source that is operated in pulses. At least one chemical element and/or at least one chemical compound is/are introduced into the hot process gas flow, ions from said at least one chemical element and/or chemical compound being converted to an excited state by the heat of the process gas flow or at least one chemical reaction being initiated such that the proportion of electromagnetic radiation which is directed onto the thermally treated or melted product, having a wavelength of ≥ 575 nm, is increased by at least 10% of the total spectrum of the electromagnetic radiation.
Description
Verfahren zum Schmelzen und Warmbehandeln von Feststoffen Process for melting and heat treating solids
Die Erfindung betrifft ein Verfahren zum Schmelzen und Warmbehandeln von Feststoffen in einem Schmelzofen oder einer Schmelzwanne sowie Chargen- und Durchlauföfen. The invention relates to a method for melting and heat treating solids in a melting furnace or a melting tank as well as to batch and continuous furnaces.
Bisher ist es üblich zum Schmelzen und Warmbehandeln dieser Feststoffe in unterschiedlich konfigurierten Öfen Öl- oder Gasbrenner einzusetzen mit deren heißer Flamme das jeweilige Material erwärmt und in die flüssige Phase überführt werden kann. Bei der Verbrennung der jeweiligen Kohlenwasserstoffverbindung, welche aus fossilen Quellen stammen, wird durch chemische Oxidation gebildetes CO2 in relativ großen Mengen mit dem Rauchgas in die Erdatmosphäre abgegeben, was unter dem Klimawandelaspekt und dem Verbrauch natürlicher fossiler Ressourcen besonders nachteilig ist. Until now, it has been common practice to use oil or gas burners to melt and heat treat these solids in differently configured furnaces, with the hot flames of which the material can be heated and converted into the liquid phase. When the respective hydrocarbon compound, which comes from fossil sources, is burned, CO2 formed by chemical oxidation is released into the earth's atmosphere in relatively large quantities with the flue gas, which is particularly disadvantageous in terms of climate change and the consumption of natural fossil resources.
Des Weiteren ist es auch bekannt, eine induktive Erwärmung und induktives Schmelzen von leitfähigen Feststoffen, insbesondere Metall als Schmelz- bzw.
Behandlungsgut durchzuführen. Infolge der dabei auftretenden elektrischen Wechselfelder tritt aber eine starke Rührwirkung der gebildeten Schmelze auf. Diese führt in hohem Maß zu Oxideinschlüssen im Metall, so dass die Qualität der mit der so erhaltenen Schmelze hergestellten Bauteile stark nachteilig beeinflusst wird. Induktiv beheizte Schmelzöfen sind weiterhin in der Regel infolge ungünstiger Ankopplungsbedingungen schlecht geeignet zum Einschmelzen grobstückigem Kreislaufmaterials oder Gussbruchs. Furthermore, it is also known to use inductive heating and inductive melting of conductive solids, in particular metal as a melting or melting agent. However, the alternating electrical fields that occur in the process cause the melt to stir strongly. This leads to a high level of oxide inclusions in the metal, which has a severe negative impact on the quality of the components produced with the resulting melt. Inductively heated melting furnaces are also generally poorly suited to melting coarse lumps of recycled material or cast iron scrap due to unfavorable coupling conditions.
Auch bekannt sind elektrisch widerstandsbeheizte Öfen. Diese weisen meist nur eine geringe Leistung auf und eignen sich daher in der Regel nur zum Warmhalten bereits flüssigen Metalls durch Unterdrückung der Wärmeverluste. Electrically resistance-heated furnaces are also known. These usually have only a low output and are therefore generally only suitable for keeping already liquid metal warm by suppressing heat loss.
In jüngerer Vergangenheit sind jedoch technische Möglichkeiten entwickelt worden, bei denen eine Warmbehandlung und das Schmelzen von Feststoffen durch Nutzung elektrischer Energie, bei der ein heißer Prozessgasstrom durch indirekte induktive Erwärmung zum Schmelzen genutzt werden kann. In recent times, however, technical possibilities have been developed that allow heat treatment and melting of solids by using electrical energy, in which a hot process gas stream can be used for melting by indirect inductive heating.
Eine solche technische Lösung, die die indirekte induktive Erwärmung eines Prozessgasstromes betrifft, ist in der DE 10 2022 207 481 Al offenbart. Auf deren Inhalt soll im Folgenden Bezug genommen werden. Such a technical solution, which concerns the indirect inductive heating of a process gas stream, is disclosed in DE 10 2022 207 481 A1. Reference will be made to its content below.
Dabei ist es aber nachteilig, dass die Erwärmung des Schmelzgutes ausschließlich mit der Wärmeenergie des Prozessgasstromes sowie mit der elektromagnetischen Strahlung erreicht werden kann. Dabei spielt auch das Wellenlängenspektrum der elektromagnetischen Strahlung eine Rolle, da bekanntermaßen unterschiedliche Wellenlängen unterschiedlich von einem entsprechend bestrahlten Werkstoff absorbiert und dabei unterschiedlich stark zu dessen Erwärmung beitragen. However, the disadvantage is that the heating of the melt can only be achieved with the thermal energy of the process gas flow and with electromagnetic radiation. The wavelength spectrum of the electromagnetic radiation also plays a role, since it is known that different wavelengths are absorbed differently by a correspondingly irradiated material and thus contribute to its heating to different degrees.
So wird von einem Prozessgasstrom, abhängig von der Art des Prozessgases, überwiegend kurzwellige elektromagnetische Strahlung emittiert, die zum Schmelzen auf das jeweilige Schmelzgut oder einer Schmelzwanne auftrifft. Diese Strahlung, die überwiegend diskrete (blaue oder grüne) Strahlungsanteile beinhaltet, wird mit einem relativ geringen Wirkungsgrad von den zu schmelzenden oder warmbehandelten Feststoffen (Metallen, Gläsern) oder
einer Schmelzwanne absorbiert, so dass der Gesamtwirkungsgrad entsprechend reduziert ist. Depending on the type of process gas, a process gas stream emits predominantly short-wave electromagnetic radiation, which impinges on the respective melting material or a melting tank for melting. This radiation, which mainly contains discrete (blue or green) radiation components, is absorbed with relatively low efficiency by the solids (metals, glasses) or a melting tank, so that the overall efficiency is reduced accordingly.
Es ist daher Aufgabe der Erfindung, Möglichkeiten anzugeben, bei denen der Wirkungsgrad beim Warmbehandeln und/oder Schmelzen von Feststoffen wie z.B. Metallen und Gläsern einfach erhöht werden kann, wenn man zur Erzeugung der erforderlichen Prozesswärme einen heißen Prozessgasstrom, der durch indirekte induktive Erwärmung erhitzt worden ist, nutzt. It is therefore an object of the invention to provide possibilities in which the efficiency of the heat treatment and/or melting of solids such as metals and glasses can be easily increased by using a hot process gas stream that has been heated by indirect inductive heating to generate the required process heat.
Erfindungsgemäß wird diese Aufgabe mit einem Verfahren, das die Merkmale des Anspruchs 1 aufweist, gelöst. Vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung können mit in abhängigen Ansprüchen bezeichneten Merkmalen realisiert werden. According to the invention, this object is achieved with a method having the features of claim 1. Advantageous embodiments and further developments of the invention can be realized with features specified in dependent claims.
Bei der Erfindung wird mindestens ein heißer Prozessgasstrom, der durch induktive Erwärmung mindestens eines Körpers, durch den und/oder an dem vorbei zu erwärmendes Prozessgas in Richtung auf zu warmbehandelnden oder schmelzenden Feststoff (Metall, Glas) oder einer Schmelzwanne oder in einem Abstand zu dessen bzw. deren Oberfläche gerichtet wird und die Erwärmung des mindestens einen Körpers mit einer diesen umschließenden elektrischen Spule, die an eine elektrische Wechselspannungsquelle oder eine gepulst betriebene elektrische Gleichspannungsquelle angeschlossen ist, erreicht wird. Dabei wird ausschließlich die Wärmeenergie des Prozessgasstromes und die emittierte elektromagnetische Strahlung zur Bereitstellung von Prozesswärme genutzt. In the invention, at least one hot process gas stream is directed by inductive heating of at least one body through and/or past which the process gas to be heated is directed towards the solid (metal, glass) to be heat-treated or melted or a melting tank or at a distance from its surface, and the heating of the at least one body is achieved with an electrical coil enclosing it, which is connected to an electrical AC voltage source or a pulsed electrical DC voltage source. Only the thermal energy of the process gas stream and the emitted electromagnetic radiation are used to provide process heat.
Erfindungsgemäß wird/werden in den heißen Prozessgasstrom mindestens ein chemisches Element und/oder mindestens eine chemische Verbindung eingeführt und von dem chemischen Element bzw. der chemischen Verbindung werden Ionen mit der Wärme des Prozessgasstromes in einen angeregten Zustand überführt. In Kombination mit der Überführung in einen angeregten Zustand werden Photonen freigesetzt. Allein oder zusätzlich zur Anregung der Ionen kann mindestens eine exotherme chemische Reaktion initiiert werden, deren Energie den Prozessgasstrom zusätzlich erwärmen kann. Bei einer chemischen Reaktion sollte möglichst kein H2 oder kein CO bzw. CO2 freigesetzt werden und in den Einflussbereich des warmzubehandelnden oder zu
schmelzenden Feststoffs bzw. eines Schmelzguts gelangen können. According to the invention, at least one chemical element and/or at least one chemical compound is/are introduced into the hot process gas flow and ions are converted into an excited state by the chemical element or chemical compound using the heat of the process gas flow. In combination with the conversion into an excited state, photons are released. Alone or in addition to the excitation of the ions, at least one exothermic chemical reaction can be initiated, the energy of which can additionally heat the process gas flow. In a chemical reaction, as little H2 or CO or CO2 as possible should be released and should not enter the sphere of influence of the material to be heat-treated or to be melting solid or melted material.
In jedem Fall wird dadurch der Anteil der elektromagnetischen Strahlung, die auf das Schmelzgut gerichtet wird, mit Wellenlängen von > 575 nm um mindestens 10 %, bevorzugt um mindestens 30 % des gesamten Spektrums der elektromagnetischen Strahlung erhöht, wobei bevorzugt ein Übergang von einem diskreten in ein kontinuierliches Strahlungsspektrum (Festköperstrahlung des Kohlenstoffs) angestrebt wird. Der Übergang in ein kontinuierliches Spektrum ermöglicht ein Eindringen des vor allem langwelligen Anteils der elektromagnetischen Strahlung in die Oberfläche des Warmbehandlungsgutes bzw. in die Schmelze hinein, wodurch ein hocheffizienter Wärmeeintrag möglich ist. Bei kurzwelliger, diskreter elektromagnetischer Strahlung hingegen dominiert die Reflexion an der Oberfläche (Feststoff bzw. Schmelze), so dass ein Großteil der Strahlungsenergie die Ofenwandungen erwärmt und mittels Konvektion ungenutzt mit den strömenden Gasen abgeführt wird. In any case, the proportion of electromagnetic radiation directed at the melt with wavelengths of > 575 nm is increased by at least 10%, preferably by at least 30% of the entire spectrum of electromagnetic radiation, with a transition from a discrete to a continuous radiation spectrum (solid-state radiation of carbon) preferably being sought. The transition to a continuous spectrum enables the long-wave portion of the electromagnetic radiation to penetrate into the surface of the heat-treated material or into the melt, which enables highly efficient heat input. With short-wave, discrete electromagnetic radiation, on the other hand, reflection at the surface (solid or melt) dominates, so that a large part of the radiation energy heats the furnace walls and is dissipated unused with the flowing gases by convection.
Bevorzugt sollte der Prozessgasstrom mit einem Winkel zwischen 0° und 20 ° in Bezug zur Oberfläche des Warmbehandlungs- oder zu schmelzenden Feststoffs bzw. bereits geschmolzenen Schmelzguts oder der Schmelzwanne ausgerichtet sein. Er kann aber auch direkt auf den warmzubehandelnden oder zu schmelzenden Feststoff gerichtet sein. Preferably, the process gas flow should be directed at an angle of between 0° and 20° in relation to the surface of the solid to be heat treated or melted, or of the already melted melt material or the melting tank. However, it can also be directed directly at the solid to be heat treated or melted.
Der so mit dem Prozessgasstrom geschmolzene Feststoff kann dann in eine Schmelzwanne oder einen Tiegel im Schmelzofen überführt werden. In einer Schmelzwanne geschmolzener Feststoff (Metall oder Glas) kann daraus abgeführt oder daraus entnommen werden. The solid thus melted with the process gas stream can then be transferred to a melting tank or crucible in the melting furnace. Solid (metal or glass) melted in a melting tank can be discharged or removed from it.
Als chemisches Element kann man Na, Ca, Sr, Li, Rb, Mg oder Kohlenstoff oder als chemische Verbindung kann man mindestens eine chemische Verbindung einsetzen, in der mindestens eines dieser chemischen Elemente enthalten ist. Von den Alkalimetallen kann man insbesondere deren Salze als chemische Verbindung einsetzen. So führt der Einsatz von Natrium oder einer Natriumverbindung zu einer Verfärbung in gelbe elektromagnetische Strahlung, bei Ca oder Calziumverbindung zu orange-rot, Sr oder einer Strontiumverbindung zu rot, Li oder einer Lithiumverbindung zu rot und Rb bzw. einer Rubidiumverbindung ebenfalls zu rot infolge des bekannten Effekts der Flammfärbung. Der
Einsatz von kohlenstoffhaltigen Verbindungen führt zu einem kontinuierlichen Spektrum mit Maximum im gelben Strahlungsbereich. The chemical element used can be Na, Ca, Sr, Li, Rb, Mg or carbon, or the chemical compound used can be at least one chemical compound containing at least one of these chemical elements. Of the alkali metals, their salts can be used as chemical compounds. The use of sodium or a sodium compound leads to a yellow discoloration of electromagnetic radiation, Ca or a calcium compound to orange-red, Sr or a strontium compound to red, Li or a lithium compound to red and Rb or a rubidium compound also to red as a result of the well-known effect of flame coloration. Use of carbon-containing compounds leads to a continuous spectrum with a maximum in the yellow radiation range.
Das mindestens eine chemische Element und/oder die mindestens eine chemische Verbindung sollte mit einem Anteil größer bis 15 Vol.-%, bevorzugt mindestens 0,2 Vol.-% bis maximal 10 Vol.-% in Bezug zum zugeführten Prozessgasstrom zugeführt werden. The at least one chemical element and/or the at least one chemical compound should be supplied in a proportion of greater than 15 vol.%, preferably at least 0.2 vol.% up to a maximum of 10 vol.% in relation to the supplied process gas stream.
Wie bereits angedeutet, kann als chemisches Element auch C oder eine Kohlenwasserstoffverbindung eingesetzt werden. As already indicated, C or a hydrocarbon compound can also be used as a chemical element.
Die Zuführung kann prinzipiell in jedem möglichen Aggregatzustand also fest, flüssig oder gasförmig erfolgen. Es besteht auch die Möglichkeit, ein chemisches Element oder eine chemische Verbindung in einem Lösungsmittel also in gelöster Form zuzuführen. In principle, the supply can be in any possible state of aggregation, i.e. solid, liquid or gaseous. It is also possible to supply a chemical element or a chemical compound in a solvent, i.e. in dissolved form.
Das mindestens eine chemische Element oder die mindestens eine chemische Verbindung sollte in einen Bereich des Prozessgasstromes zugeführt werden, in dem eine Mindesttemperatur von 750 °C eingehalten wird. Dies ist dabei von besonderer Bedeutung, wenn der Anteil langwelliger elektromagnetischer Strahlung ab Wellenlängen von 575 nm und größer durch Zuführung von chemischen Verbindungen erreicht werden soll, die dazu chemisch reagieren müssen. Dies ist insbesondere bei der Zuführung von Kohlenwasserstoffverbindungen vorteilhaft. The at least one chemical element or the at least one chemical compound should be fed into an area of the process gas flow in which a minimum temperature of 750 °C is maintained. This is particularly important if the proportion of long-wave electromagnetic radiation from wavelengths of 575 nm and greater is to be achieved by feeding chemical compounds that must react chemically. This is particularly advantageous when feeding hydrocarbon compounds.
Neben Ölen können beispielsweise auch kohlenwasserstoffhaltige Prozessgase wie Pyrolysegase, Vergasungsgase oder Fackelgase oder andere gasförmige Kohlenwasserstoffe wie Propan, oder Butan zur vorteilhaften Beeinflussung des Spektrums der zum Warmbehandeln und Schmelzen genutzten elektromagnetischen Strahlung eingesetzt werden. Es können auch weitere Gase mit ausreichend breiten Absorptionsbändern eingesetzt werden, insbesondere auch C-freie Gase (z.B. NH3) oder Gasmischungen. („Strahlung von Gasen und Dämpfen"). In addition to oils, hydrocarbon-containing process gases such as pyrolysis gases, gasification gases or flare gases or other gaseous hydrocarbons such as propane or butane can be used to advantageously influence the spectrum of electromagnetic radiation used for heat treatment and melting. Other gases with sufficiently broad absorption bands can also be used, in particular C-free gases (e.g. NH3) or gas mixtures ("Radiation of gases and vapors").
Werden insbesondere kontaminierte oder toxische Kohlenwasserstoffverbindungen zugeführt, so sollten sie so in den Einflussbereich des Prozessgasstro-
mes eingeführt werden, dass aufgrund der vorliegenden Temperaturen und Gaszusammensetzung diese chemischen Verbindungen aufgebrochen werden. Kontaminierte oder toxische Kohlenwasserstoffverbindungen können beispielsweise Öle sein, die in Transformatoren zur Kühlung genutzt worden sind. Dies können auch verbrauchte Thermoöle zur Beheizung oder Kühlung von Hochtemperaturprozessen, Öl- bzw. Teerkondensate aus Pyrolyseprozessen (biogener Reststoffe), Lösemittelabfälle, biogene oder mineralische - oder Abfallöle sein. If contaminated or toxic hydrocarbon compounds are added, they should be introduced into the sphere of influence of the process gas flow. The gases must be introduced in such a way that these chemical compounds are broken down due to the temperatures and gas composition present. Contaminated or toxic hydrocarbon compounds can be, for example, oils that have been used for cooling in transformers. These can also be used thermal oils for heating or cooling high-temperature processes, oil or tar condensates from pyrolysis processes (biogenic residues), solvent waste, biogenic or mineral oils or waste oils.
So kann man das erfindungsgemäße Verfahren auch für eine gefahrlose Entsorgung nutzen, da die gefährlichen Komponenten chemisch in nicht oder erheblich weniger gefährliche Komponenten umgewandelt werden können und gleichzeitig zur Erhöhung des Wirkungsrades beim Warmbehandeln und Schmelzen genutzt werden können. Thus, the process according to the invention can also be used for safe disposal, since the hazardous components can be chemically converted into non-hazardous or significantly less hazardous components and at the same time can be used to increase the efficiency during heat treatment and melting.
Insbesondere Kohlenwasserstoffverbindungen können direkt in den heißen Prozessgasstrom eingeführt werden, so dass für eine Dekomposition durch chemische Reaktion(en) ausreichend hohe Temperaturen zur Verfügung stehen. Dort kommt es somit zur vollständigen Zersetzung und Oxidation der Kohlenwasserstoffe. Zum Beispiel Aromaten wie Toluol, Benzol, Phenol, Xylol oder Furan In particular, hydrocarbon compounds can be introduced directly into the hot process gas stream so that sufficiently high temperatures are available for decomposition through chemical reaction(s). This is where the hydrocarbons are completely decomposed and oxidized. For example, aromatics such as toluene, benzene, phenol, xylene or furan
(Bsp. Toluol: C7HS + W2 4H2O + 7CO2 ) sowie polycyclische aromatische Kohlenwasserstoffe wie Naphthalin, Fluoren oder Pyren (e.g. toluene: C 7 H S + W 2 4H 2 O + 7CO 2 ) and polycyclic aromatic hydrocarbons such as naphthalene, fluorene or pyrene
(Bsp. Naphthalin: CWHS + 1202 — 4H2O + 10CCU) können unschädlich gemacht werden. (e.g. naphthalene: C W H S + 120 2 — 4H 2 O + 10CCU) can be rendered harmless.
Die bei Verwendung dieser Additive freigesetzte Konzentration an CO2 im Rauchgas ist infolge der sehr geringen Dosierung / Beimischung äußerst gering.
Chemische Elemente und chemische Verbindungen, die erfindungsgemäß zugeführt werden, können aber auch unmittelbar oder in einem Abstand von bevorzugt maximal 50 mm nach Austritt des Prozessgasstromes aus der Vorrichtung zugeführt werden. The concentration of CO2 released in the flue gas when using these additives is extremely low due to the very low dosage/admixture. Chemical elements and chemical compounds which are supplied according to the invention can also be supplied directly or at a distance of preferably a maximum of 50 mm after the process gas stream exits the device.
Das erfindungsgemäße Verfahren kann mit einer Vorrichtung, wie sie in DE 10 2022 207 481 Al beschrieben ist, durchgeführt werden. Auf deren Offenbarungsgehalt soll vollinhaltlich Bezug genommen werden. The method according to the invention can be carried out with a device as described in DE 10 2022 207 481 A1. Reference is made to the entire disclosure content of this document.
Bei dieser Vorrichtung durchströmt ein Prozessgas einen ersten innen hohlen Körper mit einem vorgebbaren Volumenstrom von einem Eintritt zu einem Austritt. Der erste innen hohle Körper ist von mindestens einer elektrischen Spule umschlossen bzw. umgeben, die an eine elektrische Spannungsquelle, mit der Wechselspannung oder eine gepulste Gleichspannung an die elektrische Spule angelegt wird, angeschlossen ist. Mit der mindestens einen elektrischen Spule ist eine Erwärmung durch elektrische Induktion des ersten innen hohlen Körpers oder mindestens eines Metallkörpers, der/die im Inneren des ersten innen hohlen Körpers angeordnet ist/sind, erreichbar. Dabei strömt das Prozessgas zu seiner Erwärmung an der Innenwand des ersten innen hohlen Körpers und/oder der Oberfläche, bevorzugt der äußeren Oberfläche des mindestens einen Metallkörpers entlang. Der erste innen hohle Körper und der mindestens eine Metallkörper sind jeweils aus einem Werkstoff gebildet, dessen Schmelztemperatur größer als die Maximaltemperatur des erwärmten Prozessgases ist. In this device, a process gas flows through a first internally hollow body with a predeterminable volume flow from an inlet to an outlet. The first internally hollow body is enclosed or surrounded by at least one electrical coil that is connected to an electrical voltage source with which alternating voltage or a pulsed direct voltage is applied to the electrical coil. The at least one electrical coil can be used to heat the first internally hollow body or at least one metal body that is/are arranged inside the first internally hollow body by electrical induction. The process gas flows along the inner wall of the first internally hollow body and/or the surface, preferably the outer surface of the at least one metal body, to heat it. The first internally hollow body and the at least one metal body are each made of a material whose melting temperature is greater than the maximum temperature of the heated process gas.
Der erste innen hohle Körper und/oder der mindestens eine Metallkörper kann/können aus einem Stahl und/oder einem Refraktärmetall und/oder seinen Legierungen - insbesondere einer Tantal-, Wolfram-, Niob-, oder Molybdänbasislegierung - gebildet sein. In einer Basislegierung sind die genannten Metalle mit mindestens 50 Masse-% enthalten. Der erste innen hohle Körper kann aber auch aus einem Feuerfestmaterial, insbesondere Quarzglas, AI2O3, ZrÜ2 oder MgO gebildet sein, das nicht induktiv erwärmt werden kann. Dies ist insbesondere dann der Fall, wenn in seinem Inneren der mindestens eine Metallkörper angeordnet ist und dieser induktiv erwärmt wird.
Mehrere Metallkörper können auch als lose Schüttung und/oder Ver- bundkörper im Inneren des innen hohlen Körpers angeordnet sein, die vom Prozessgas umströmt werden und dabei das Prozessgas entlang des Strömungswegs vom Eintritt zum Austritt erwärmt wird. The first internally hollow body and/or the at least one metal body can be made of a steel and/or a refractory metal and/or its alloys - in particular a tantalum, tungsten, niobium or molybdenum-based alloy. A base alloy contains at least 50% by mass of the metals mentioned. The first internally hollow body can also be made of a refractory material, in particular quartz glass, Al2O3, ZrÜ2 or MgO, which cannot be heated inductively. This is particularly the case if the at least one metal body is arranged in its interior and is heated inductively. Several metal bodies can also be arranged as loose fill and/or composite bodies inside the internally hollow body, around which the process gas flows and the process gas is heated along the flow path from the inlet to the outlet.
Als Prozessgas kann Luft, aber auch ein anderes Gas oder Gasgemisch eingesetzt werden, das vorteilhaft für den jeweiligen Erwärmungsprozess sein kann. Dies schließt insbesondere auch inerte Gase ein, die eine Beeinflussung der zu erwärmenden Elemente, Stoffe und Gegenstände vermeiden können. The process gas used can be air, but also another gas or gas mixture that may be advantageous for the respective heating process. This particularly includes inert gases that can avoid influencing the elements, materials and objects to be heated.
Der Metallkörper kann in Form einer Schnecke, bei der das zu erwärmende Prozessgas durch die Windungen der Schnecke strömt, oder in Form einer Spirale ausgebildet sein. Dabei kann die vergrößerte Oberfläche des mindestens einen Metallkörpers vorteilhaft für die Wärmeübertragung auf das Prozessgas ausgenutzt werden. Es besteht aber auch die Möglichkeit, Metallkörper mit Konturelementen (Erhebungen, Vertiefungen) zur Vergrößerung der Gesamtoberfläche des mindestens einen Metallkörpers einzusetzen. The metal body can be designed in the form of a screw, in which the process gas to be heated flows through the turns of the screw, or in the form of a spiral. The enlarged surface of the at least one metal body can be used advantageously for heat transfer to the process gas. However, it is also possible to use metal bodies with contour elements (elevations, depressions) to enlarge the total surface of the at least one metal body.
Es besteht auch die Möglichkeit, dass die mindestens eine elektrische Spule einen aus einem Metall gebildeten zweiten innen hohlen Körper, neben dem aus einem nichtmetallischen Werkstoff gebildeten ersten innen hohlen Körper und den mindestens einen Metallkörper umschließt. Dabei kann der zweite innen hohle Körper aus einem geeigneten Metall oder einer geeigneten Keramik und der erste innen hohle Körper kann aus einem nichtmetallischen Werkstoff, insbesondere einem keramischen Werkstoff gebildet sein. Dabei sollen beide innen hohlen Körper eine ausreichend hohe Schmelztemperatur aufweisen. It is also possible for the at least one electrical coil to enclose a second internally hollow body made of a metal, in addition to the first internally hollow body made of a non-metallic material and the at least one metal body. The second internally hollow body can be made of a suitable metal or a suitable ceramic and the first internally hollow body can be made of a non-metallic material, in particular a ceramic material. Both internally hollow bodies should have a sufficiently high melting temperature.
Am Eintritt in die Vorrichtung für das Prozessgas kann ein feuerfestes Verschlusselement zur Vermeidung einer Rückströmung von dem erwärmten Prozessgas angeordnet sein. Dadurch lassen sich Energie- und insbesondere Wärmeverluste reduzieren und der Prozessgaseintritt erfolgt ausschließlich über den entsprechend dimensionierten Eintritt.
Der erste innen hohle Körper und der Meta II körper sowie ein ggf. vorhandener zweiter innen hohler Körper sollten rohrförmig ausgebildet sein. Der oder die Körper könnten auch andere Geometrien ihrer inneren freien Querschnittsflächen und/oder ihrer Oberflächen aufweisen. Die Rohrform bietet aber strömungstechnisch und wegen der relativ großen Oberfläche, die zur Erwärmung des Prozessgases beitragen, Vorteile. A fireproof closure element can be arranged at the inlet to the device for the process gas to prevent backflow of the heated process gas. This reduces energy and especially heat losses and the process gas enters exclusively via the appropriately dimensioned inlet. The first internally hollow body and the Meta II body, as well as any second internally hollow body, should be tubular. The body or bodies could also have other geometries of their internal free cross-sectional areas and/or their surfaces. However, the tubular shape offers advantages in terms of flow technology and because of the relatively large surface area, which contributes to heating the process gas.
Der erste innen hohle Körper kann von einem zweiten und/oder einem dritten innen hohlen Körper umschlossen sein, so dass durch einen Spalt zwischen dem ersten innen hohlen Körper und dem zweiten innen hohlen Körper und/oder durch einen Spalt zwischen dem zweiten innen hohlen Körper und dem dritten innen hohlen Körper zur Erwärmung des Prozessgases im Gegenstrom oder Gleichstrom zur Prozessgasströmung Prozessgas strömt. So ist eine effektive Vorwärmung von Prozessgas und eine Nutzung von Abwärme möglich. The first internally hollow body can be enclosed by a second and/or a third internally hollow body, so that process gas flows through a gap between the first internally hollow body and the second internally hollow body and/or through a gap between the second internally hollow body and the third internally hollow body in order to heat the process gas in countercurrent or cocurrent to the process gas flow. This enables effective preheating of process gas and utilization of waste heat.
Bei der Erfindung kann die Temperatur des aus dem Austritt austretenden Prozessgases mit einer Anpassung des Prozessgasvolumenstroms und/oder der elektrischen Leistung, mit der die mindestens eine elektrische Spule betrieben wird, geregelt werden. Dazu kann die Temperatur des Prozessgases am Austritt bestimmt werden. In the invention, the temperature of the process gas exiting the outlet can be regulated by adjusting the process gas volume flow and/or the electrical power with which the at least one electrical coil is operated. For this purpose, the temperature of the process gas at the outlet can be determined.
Prozessgas durchströmt die Vorrichtung, tritt am Austritt als Heißgas aus und kann als Heißgasfackel verwendet werden. Process gas flows through the device, exits as hot gas and can be used as a hot gas flare.
Wesentlich für den Wirkungsgrad ist dabei der gute Wärmeübergang vom/von Metallkörper(n) an das vorbeiströmende Prozessgas. Durch eine Rohr-in-Rohr-Lösung mit mehreren innen hohlen Körpern kann eine Wärmeisolation und Vorwärmung des Prozessgases erreicht werden, was den Wirkungsgrad verbessert. The key to efficiency is the good heat transfer from the metal body(s) to the process gas flowing past. A pipe-in-pipe solution with several hollow bodies inside can achieve thermal insulation and preheating of the process gas, which improves efficiency.
Das mindestens eine chemische Element oder die mindestens eine chemische Verbindung kann in das Innere eines innen hohlen Körpers oder nach dem Austritt des heißen Prozessgasstromes aus der Vorrichtung in den heißen Pro-
zessgasstrom eingeführt werden, um die erfindungsgemäß gewünschte Beeinflussung des Strahlungsspektrums der zur Erwärmung von Schmelzgut oder einer Schmelzwanne genutzten elektromagnetischen Strahlung zu erreichen.
The at least one chemical element or the at least one chemical compound can be introduced into the interior of a hollow body or into the hot process gas stream after it has exited the device. process gas stream in order to achieve the desired influence according to the invention on the radiation spectrum of the electromagnetic radiation used to heat melting material or a melting tank.
Claims
Patentansprüche Verfahren zum Warmbehandeln und Schmelzen von Feststoffen, insbesondere Metall oder Glas, bei dem mindestens ein heißer Prozessgasstrom, der durch induktive Erwärmung mindestens eines Körpers, durch den und/oder an den vorbei zu erwärmendes Prozessgas in Richtung auf zu warmbehandelnden oder schmelzenden Feststoff oder in einem Abstand entlang oder direkt auf die Oberfläche des warmzubehandelnen oder zu schmelzenden Feststoffs oder einer Schmelzwanne gerichtet wird und die Erwärmung des mindestens einen Körpers mit einer diesen umschließenden elektrischen Spule, die an eine elektrische Wechselspannungsquelle oder eine gepulst betriebene elektrische Gleichspannungsquelle angeschlossen ist, erreicht wird, wobei in den heißen Prozessgasstrom mindestens ein chemisches Element und/oder mindestens eine chemische Verbindung eingeführt wird/werden, von dem/der Ionen mit der Wärme des Prozessgasstromes in einen angeregten Zustand überführt werden oder mindestens eine chemische Reaktion initiiert wird, so dass der Anteil der elektromagnetischen Strahlung, die auf das Warmbehandlungs- oder Schmelzgut gerichtet wird, mit Wellenlängen von > 575 nm um mindestens 10 % des gesamten Spektrums der elektromagnetischen Strahlung erhöht wird. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass der Prozessgasstrom mit einem Winkel zwischen 0° und 20 ° in Bezug zur Oberfläche des Feststoffs, Warmbehandlungs- oder eines Schmelzguts oder der Oberfläche einer Schmelzwanne gerichtet wird.
Patent claims Method for the heat treatment and melting of solids, in particular metal or glass, in which at least one hot process gas stream, which is generated by inductive heating of at least one body, through and/or past the process gas to be heated, is directed in the direction of the solid to be heat treated or melted or at a distance along or directly onto the surface of the solid to be heat treated or melted or a melting tank, and the heating of the at least one body is achieved with an electrical coil enclosing it, which is connected to an electrical alternating voltage source or a pulsed electrical direct voltage source, wherein at least one chemical element and/or at least one chemical compound is/are introduced into the hot process gas stream, ions of which are converted into an excited state with the heat of the process gas stream or at least one chemical reaction is initiated, so that the proportion of electromagnetic radiation directed at the material to be heat treated or melted with wavelengths of > 575 nm is increased by at least 10% of the entire spectrum of electromagnetic radiation. Method according to claim 1, characterized in that the process gas flow is directed at an angle between 0° and 20° with respect to the surface of the solid, heat treatment or melting material or the surface of a melting tank.
3. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass als chemisches Element Na, Ca, Sr, Li, Rb, Mg oder Kohlenstoff oder als chemische Verbindung in der mindestens eines dieser chemischen Elemente enthalten ist, eingesetzt wird. 3. Method according to one of the preceding claims, characterized in that the chemical element used is Na, Ca, Sr, Li, Rb, Mg or carbon or the chemical compound containing at least one of these chemical elements.
4. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass das mindestens eine chemische Element und/oder die mindestens eine chemische Verbindung mit einem Anteil größer als 0 Vol.- bis 15 Vol.-% in Bezug zum zugeführten Prozessgasstrom zugeführt wird. 4. Method according to one of the preceding claims, characterized in that the at least one chemical element and/or the at least one chemical compound is supplied in a proportion of greater than 0 vol. to 15 vol. % in relation to the supplied process gas stream.
5. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass das mindestens ein chemisches Element oder die mindestens eine chemische Verbindung in einen Bereich des Prozessgasstromes zugeführt wird, in dem eine Mindesttemperatur von 750 °C eingehalten wird. 5. Method according to one of the preceding claims, characterized in that the at least one chemical element or the at least one chemical compound is fed into a region of the process gas stream in which a minimum temperature of 750 °C is maintained.
6. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass als mindestens eine chemische Verbindung ein Salz oder eine Kohlenwasserstoffverbindung eingesetzt wird. 6. Process according to one of the preceding claims, characterized in that a salt or a hydrocarbon compound is used as at least one chemical compound.
7. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Anteil an elektromagnetischer Strahlung mit Wellenlängen > 575 nm um mindestens 30 % erhöht wird. 7. Method according to one of the preceding claims, characterized in that the proportion of electromagnetic radiation with wavelengths > 575 nm is increased by at least 30%.
8. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass kontaminierte oder toxische Kohlenwasserstoffverbindungen so in den Einflussbereich des Prozessgasstromes eingeführt werden, dass aufgrund der hohen Temperaturen und der vorherrschenden Gaszusammensetzung chemische Verbindungen aufgebrochen werden und somit die im Prozessgasstrom enthaltenen Anteile kontaminierter oder toxischer Verbindungen wesentlich reduziert werden. 8. Method according to one of the preceding claims, characterized in that contaminated or toxic hydrocarbon compounds are introduced into the sphere of influence of the process gas stream in such a way that chemical compounds are broken down due to the high temperatures and the prevailing gas composition and thus the proportions of contaminated or toxic compounds contained in the process gas stream are significantly reduced.
9. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass feste, gasförmige oder flüssige Produkte aus der thermischen Spaltung oder Vergasung von Biomassen, Reststoffen, Ab-
fällen oder fossilen Energieträgern als chemische Verbindung(en) eingesetzt werden.
9. Process according to one of the preceding claims, characterized in that solid, gaseous or liquid products from the thermal cracking or gasification of biomass, residues, waste precipitation or fossil fuels as chemical compound(s).
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DE102022211216.4A DE102022211216A1 (en) | 2022-10-21 | 2022-10-21 | Process for melting and heat treating solids |
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US6049559A (en) * | 1996-10-04 | 2000-04-11 | Shinko Electric Co., Ltd. | Method of refining metal to high degree of purity and high-frequency vacuum induction melting apparatus |
US9284210B2 (en) * | 2014-03-31 | 2016-03-15 | Corning Incorporated | Methods and apparatus for material processing using dual source cyclonic plasma reactor |
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DE69427412T2 (en) | 1993-03-08 | 2001-10-25 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | Plasma furnace |
EP0896955A1 (en) | 1997-08-12 | 1999-02-17 | Von Roll Umwelttechnik AG | Method and apparatus for the reduction of metal in a glass or slagmelt |
DE102006029724B4 (en) | 2006-06-28 | 2008-12-04 | Siemens Ag | Method and furnace for melting steel scrap |
DE102006029725B4 (en) | 2006-06-28 | 2008-08-28 | Siemens Ag | Method and device for introducing dusts into a molten metal of a pyrometallurgical plant |
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US6049559A (en) * | 1996-10-04 | 2000-04-11 | Shinko Electric Co., Ltd. | Method of refining metal to high degree of purity and high-frequency vacuum induction melting apparatus |
US9284210B2 (en) * | 2014-03-31 | 2016-03-15 | Corning Incorporated | Methods and apparatus for material processing using dual source cyclonic plasma reactor |
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