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
  • F27B1/00—Shaft or like vertical or substantially vertical furnaces
  • F27B1/02—Shaft or like vertical or substantially vertical furnaces with two or more shafts or chambers, e.g. multi-storey
  • F27B1/025—Shaft or like vertical or substantially vertical furnaces with two or more shafts or chambers, e.g. multi-storey with fore-hearth
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B3/00—Charging the melting furnaces
  • C03B3/02—Charging the melting furnaces combined with preheating, premelting or pretreating the glass-making ingredients, pellets or cullet
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
  • C03B37/08—Bushings, e.g. construction, bushing reinforcement means; Spinnerettes; Nozzles; Nozzle plates
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2204/00—Supplementary heating arrangements
  • F23G2204/20—Supplementary heating arrangements using electric energy
  • F23G2204/201—Plasma

Definitions

• This invention concerns a method for tiie production of a melt from minerals and/or raw materials, especially for mineral wool.
• the basic energy generating properties of a plasma are used in order to perform a number of very important improvements regarding both the flexibility in the choise of energy and material efficiency and further by simple means governing an efficient emiss ion control during the operation.
• the invention also concerns an apparatus to perform the new method.
• Methods for melting the mentioned material are in itself known and are comprising of simple and well-established technology. So melting of lumps of raw material in a cupola furnace by using coke as a fuel may be mentioned.
• the main purpose of the invention is to bring about a method and an apparatus as was mentioned in the introauction, so simplifying the well-known technology and the production of the mentioned melt can be performed in many ways in order to get a cheap and competative final product.
• This is achieved by the invented method primarely by feeding the material as lumps at a first place of a process furnace, and a high temperature process gas heated by a plasma generated in a plasma generator is introduced at a second place and so supplying at least part of the energy required for the melting of the raw material feed.
• a further advantage of the invention is the reuse of practically all process waste as slag granules, fibrous material and/or waste material and so contributing to the over all process economy and the mentioned fine particle fraction can be used either as a raw material substitute or as an energy carrier.
• the gas temperature in the front of the reaction chamber can be lowered by converting part of the fuel's carbon content by a recycled process gas rich in carbon dioxide and water vapour to carbon monoxide and hydrogen and so being able to generate energy by the final combustion further in the process.
• the central process step in order to produce a melt has been given an increased interest by the opportunity to use the high temperature region of the furnace in decomposing various waste materials formed both in the following process steps and in other processes within a plant.
• the method of using the plasma technique for melting the actual material is according to the generated high temperature and reaction intensity giving unique opportunities by a simultaneous recovery of the waste bound energy.
• the cupola furnace is in connection with melting basalt known to give a very unsatisfactory combustion of the various gases as carbon monoxide, hydrogen sulphide, carbonoxy sulphide, carbon disulphide and other sulphur compounds.
• This fact is on the other hand easy to understand according to the badly defined mass transfer at the solid/gas contact between the charged coke and the oxygen in the process gas.
• the final combustion is completed in a turbulent gas/gas contact in the charge column also giving a well defined oxidation potential due to a well defined reaction system.
• the decisive effect of the invention regarding a heavily decreased emission is however the opportunities of the plasma technique to generate a process gas of a high energy density.
• the selected partition of energy between on one side plasma energy and on the other side combustion energy from the carrier gas and coal or other solid fuels is finally determined by the balance between energy cost, process requirements related to as for instance the temperature profile and the cost of the exhaust gas cleaning.
• energy cost process requirements related to as for instance the temperature profile and the cost of the exhaust gas cleaning.
• the cupola operation great opportunities for the control of the total energy supply as well as the temperature profile and oxygen potential are at hand according to this invention.
• oxygen potential is important in order to avoid or at the best strongly eliminate the risks for the reduction of iron that is a serious draw-back at the traditional cupola operation used for the melting of basalt.
• the developed process according to the invention can in order to melting materials be performed in a process furnace of a type shown in the drawing.
• the furnace is illustrated in a simplified way and in a side projection.
• the combustion or process furnace comprises of a vertical chamber of shaft 10, comprising a sintering/melting zone 12, a secondary zone 14 and an aftercombustion zone 16.
• a vertical chamber of shaft 10 comprising a sintering/melting zone 12, a secondary zone 14 and an aftercombustion zone 16.
• the temperature control regarding the material 18 being charged in to the upper part of the shaft is maintained by an adjustable lock 24.
• an adjustable lock 24 For this purpose in itself well-known but not shown in the drawing air feed equipment is used.
• the material 18 either as a primary material as lumps of suitable size or a material in advance crushed to lumps, are stored in a material storage 20 with a control device 22 for charging through the above mentioned charging lock 24.
• a horizontal en larged part 26 comprising of a conditioning zone 28, where an eventual tapping of formed metal 30 is taking place.
• a plasma generator 32 with parts 34, 36 for the supply of electric energy and water cooling is connected with a mixing zone 38.
• the produced melt 42 is discharged at the discharging devices 40 and is further spun with conventional devices 44 in a conventional way to produce stone wool, glass wool or the like.
• process gas is fed from the plasma generator 32. Over separate feed pipes 45, 46, 48 it is further possible to feed a fine fraction of the material 18, solid fuels resp. waste into the mixing chamber 38.
• a recirculation system 50 through which exhaust gases from the sintering and melting zone 12 are withdrawn above the charge level in the shaft 10 and are recirculated to the plasma generator 32 over scrubbers and filtering devices 52 resp. 54 in order to be utilized in the process gas.
• the exhaust gas system 50 there are close to the afterccmbustion zone 16 devices 56 for the disharge of sludge.
• the flow control is taking place.
• Close to the filtering devices 54 is also a cyclone 60 connected in a traditional way.
• the material 18 in the form of lumps is fed over the lock 24 into the brick-lined shaft 10.
• the escaping process gas is finally burnt in the aftercombustion zone 16 before the entry into the gas cleaning section.
• the charge is passing downwards under a temperature increase by burning of process gas at different levels in such a way that the charge column will start melting at the intended place in the shaft and from the charge formed gases are burnt as intended.
• a correct control of temperature and oxygen content is regulating the combustion.
• the charge column reaches the final melting at the brick-lined horizontal part of the furnace 26 and is exposed to the superheated melt as well as hot process gases.
• the melt is overheated to a suitable temperature for the subsequent manufacturing process by heat transfer from the hot gases immediately after the plasma generator 32 and by heat radiation from the furnace surfaces.
• Eventually formed iron is collected in the furnace bottom and is tapped in a convenient manner through the tap hole 62.
• the melt is tapped continuously. Close in the front of the opening of the plasma generator a mixture of fine material, waste fibres or waste and different fuels like fossile fuels are injected. At the same place also different so called non-process waste may be injected for a total decomposition in the hot part of the furnace.
• recirculated and fully burnt process gas can be introduced at this stage.
• the exhaust gas cleaning may take place in the simplest way by a primary SO 2 -absorption in a quasi-dry slurry scrubber 52.
• the neutralized product formed is separated either in a combination of the cyclone 60 and in the filtering devices 54 or alone in the filtering devices , and the clean exhaust gases are conducted to a stack 64 over a fan (not shown) .
• the combustion furnace may of cource be modified in many different ways. This is especially actual for the lower part of the furnace. It is thus also possible to exclude that part of furnace 26 and to arrange for the feed of the process gas at the lower part of the shaft. In this case it is convenient to use a special feeder located at the lower part of the process furnace and that is equipped with temperature control instruments for the regulation of the final melt temperature.
• the produced exhaust gas is calculated to approx. 1700 Nm 3
• exhaust gases are recirculated to such an amount that the supplied electric energy to the plasma generator - 850 kWh per metric ton of molten basalt - can be distributed to at least 150 Nm 3 of carrier gas or with an energy content of approx. 6 kWh/Nm 3.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Manufacturing & Machinery (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
• Glass Melting And Manufacturing (AREA)
• Gasification And Melting Of Waste (AREA)
• Processing Of Solid Wastes (AREA)

Applications Claiming Priority (2)

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• 1980
  • 1980-07-25 SE SE8005400A patent/SE8005400L/ not_active Application Discontinuation
• 1981
  • 1981-03-17 SE SE8101701A patent/SE8101701L/ not_active Application Discontinuation
  • 1981-07-10 WO PCT/SE1981/000213 patent/WO1982000460A1/en unknown
  • 1981-07-10 EP EP19810902015 patent/EP0057195A1/de not_active Withdrawn

Non-Patent Citations (1)

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