Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
  • F23G7/06—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F22—STEAM GENERATION
  • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
  • F22B1/00—Methods of steam generation characterised by form of heating method
  • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
  • F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
  • F22B1/183—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines in combination with metallurgical converter installations
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/44—Details; Accessories
  • F23G5/46—Recuperation of heat
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J15/00—Arrangements of devices for treating smoke or fumes
  • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
• • 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
  • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
  • F27D17/004—Systems for reclaiming waste heat

Definitions

• the invention relates to a heat recovery steam generator for the cooling of hot flue gases from metallurgical processes and a method for operating a heat recovery steam generator.
• Such heat recovery steam generators or heat recovery boilers usually comprise a radiation section and a convection section. After-reactions, such as oxidation of sulphur and metals, take place on a large scale in the radiation section of the heat recovery steam generator.
• the oxygen required for such reactions is blown in the form of oxygen-containing gas, usually air or oxygen-enriched air, for the most part with additional nozzles into the radiation section or radiation chamber (a much smaller part of the air flows through leakage openings into the heat recovery steam generator, since a partial vacuum prevails in the heat recovery steam generator).
• the nozzles serve not only to feed oxygen-containing gas, but also ensure the increase in the flow turbulence inside the radiation chamber and thus improve the mixing of the flue gases from the metallurgical process furnace with the oxygen-containing gas, in order to accelerate the required chemical reaction.
• a greater number of nozzles usually has to be installed in order to achieve uniform mixing.
• the installation of additional platen heating surfaces is often also required in order to achieve uniformity of the flow and mixing over the height of the heat recovery steam generator.
• the nozzles viewed over width B of the heat recovery steam generator, are disposed at a distance of 200 to 1000 mm from one another. This thus ensures that sufficient feeding of oxygen-containing gas for the efficient after-reaction of constituents of the flue gas takes place over the width of the heat recovery steam generator.
• the nozzles are preferably disposed in at least one plane. Optimum feeding of oxygen-containing gas is thus ensured.
• the clear cross- section of the nozzles is round.
• the form of the gas outflow cone can thus be influenced and the achievable width of the mixing can thus be improved.
• the time periods or cycle times of the pulsating injection of the oxygen-containing gas i.e. the time from the start of one injection to the start of the next injection, between 1 and 10 seconds, wherein furthermore the duration of the injection itself, i.e. the pulse duration, lies between 0.5 and 5 seconds in an advantageous embodiment.
• the duration of the cycle times and of the pulse duration is dependent on the size and the geometry of the heat recovery steam generator. It also influences the turbulence and the effective mixing of the oxygen-containing gas with the flue gas.
• the exit speed of the oxygen-containing gas brought in through the nozzles amounts to 20 to 100 m/s. The effect of this is that the penetration depth of the oxygen-containing gas into the flue gases becomes as great as possible and a correspondingly high turbulence in the flue gas is generated.
• air is expedient to use air as an oxygen-containing gas.
• the use of air as an available operating medium is cost neutral and thus easy to manage.
• a further advantageous embodiment of the invention makes provision to use water vapour of a water-vapour/air mixture as an oxygen-containing gas.
• Water vapour or a water-vapour/air mixture usually has a higher pressure compared to atmospheric pressure. Means for increasing the pressure of this medium can thus be dispensed with.
• Fig. 1 shows, represented diagrammatically, a radiation chamber of a heat recovery steam generator in longitudinal cross-section
• Fig. 2 shows, represented diagrammatically, a cross-section through the radiation chamber according to cross-section A-A in figure 1 .
• FIG. 1 shows radiation chamber 2 of a heat recovery steam generator, into which the hot process or flue gases 5 from a metallurgical process, for example from a melting or convection furnace not represented (in which a reduction process takes place), are introduced in its front part.
• Radiation chamber 2 is constituted with radiant heating surfaces not represented, through which a working fluid, usually water or steam, flows. The working fluid takes up heat from hot flue gas 5 and thereby cools down flue gas 5.
• flue gas 5 After flowing through radiation chamber 2, flue gas 5 then flows out of rear part 9 of radiation chamber 2 into the convection section (not represented) of heat recovery steam generator 1 , in which further heat is removed from the flue gas, which is taken up by the working fluid flowing in the heating surfaces of the convection section.
• the cooling of flue gas 5 below a specific temperature is necessary in order to enable further process-related processing of flue gases 5.
• Nozzles 4 are disposed approximately at 90° to upper enclosing wall 10 of radiation chamber 2 and in enclosing wall 10 (i.e. nozzles 4 penetrate enclosing wall 10), wherein enclosing wall 10 is constituted at an angle in front part 3 of radiation chamber 2. Furthermore, nozzles 4 are preferably installed in upper enclosing wall 10, it also being possible for them to be disposed in lower enclosing wall 10.
• the injection of oxygen- containing gas 6 takes place via a plurality of nozzles 4, which are distributed uniformly over width B of radiation chamber 2.
• Nozzles 4 are preferably disposed at a distance A of 200 to 1000 mm from one another, wherein nozzles 4 lie on a plane as represented in figure 2. It is however also possible to design the distances of nozzles 4 from one another differently, for example to select closer distances in the centre than at the outside. A further variant, not represented, makes provision to dispose nozzles 4 on two or more planes.
• nozzles 4 preferably have in each case a clear cross-section Q of approximately 1 to approximately 200 cm 2 , wherein the cross-sections of nozzles 4 can be constituted round or oblong.
• the exit speed of oxygen-containing gas 6 brought in through nozzles 4 preferably amounts to 20 to 100 m/s. Optimum penetration of oxygen-containing gas 6 into flue gas 5 is thus ensured. Furthermore, the time periods or cycle times of the pulsating injection of oxygen-containing gas 6, i.e. the time from the start of one injection to the start of the next injection, are preferably between 1 and 10 seconds, wherein the duration of the injection itself, i.e. the pulse duration, lies between 0.5 and 5 seconds.
• feed line 7 to nozzle 4 is provided with a means 8 for effecting a pulsating feeding.
• means 8 is a quick-opening shut-off valve.
• the cycle time and pulse duration of the injection of oxygen-containing gas 6 can be fixed as required by means of this quick-opening shut-off valve 8, which is controlled by a control device not represented.
• a feed line 7 with a means 8 can be provided for each nozzle 4. It is however also possible to serve a plurality of nozzles 4 with one feed line 7 and to provide this feed line 7 with a means 8, for example one feed line 7 serves all nozzles 4. Feed line 7 thereby branches before nozzles 4 corresponding to the number of nozzles 4 to be served.
• water vapour or a water-vapour/air mixture can be used as an oxygen-containing gas.
• Water vapour or a water-vapour/air mixture usually has a higher pressure compared to atmospheric pressure. A means for increasing the pressure of this medium can thus be dispensed with and a reduction in efficiency can thus be avoided.
• Processes e.g. pyrite and zinc-blende roasting, sulphur burning or acid cleavage, can be carried out with the present heat recovery steam generator and the method for operating such a heat recovery steam generator.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

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• 2011
  • 2011-04-20 DE DE201110002205 patent/DE102011002205A1/de not_active Withdrawn
• 2012
  • 2012-04-17 WO PCT/IB2012/000770 patent/WO2012143783A2/en active Application Filing

Non-Patent Citations (1)

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