WO2007011141A1 - Apparatus and method for incinerating waste by recycling exhaust gas of incinerator such that exhaust gas is mixed with oxygen - Google Patents

Apparatus and method for incinerating waste by recycling exhaust gas of incinerator such that exhaust gas is mixed with oxygen Download PDF

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Publication number
WO2007011141A1
WO2007011141A1 PCT/KR2006/002788 KR2006002788W WO2007011141A1 WO 2007011141 A1 WO2007011141 A1 WO 2007011141A1 KR 2006002788 W KR2006002788 W KR 2006002788W WO 2007011141 A1 WO2007011141 A1 WO 2007011141A1
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WO
WIPO (PCT)
Prior art keywords
gas
recycle gas
oxygen
waste
combustion
Prior art date
Application number
PCT/KR2006/002788
Other languages
French (fr)
Inventor
Yeonggil Ha
Yunha Kim
Original Assignee
Korea Environment Technology Co., Ltd.
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Publication date
Application filed by Korea Environment Technology Co., Ltd. filed Critical Korea Environment Technology Co., Ltd.
Publication of WO2007011141A1 publication Critical patent/WO2007011141A1/en

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Classifications

    • 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
    • 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
    • F23G5/50—Control or safety arrangements
    • 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
    • F23G5/006—General arrangement of incineration plant, e.g. flow sheets
    • 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
    • F23G5/02—Incineration of waste; Incinerator constructions; Details, accessories or control therefor with pretreatment
    • F23G5/04—Incineration of waste; Incinerator constructions; Details, accessories or control therefor with pretreatment drying
    • 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
    • F23G5/08—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating
    • F23G5/14—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating including secondary combustion
    • F23G5/16—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having supplementary heating including secondary combustion in a separate combustion chamber
    • 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
    • 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
    • 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
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L7/00—Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam
    • F23L7/007—Supplying oxygen or oxygen-enriched air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N3/00—Regulating air supply or draught
    • F23N3/08—Regulating air supply or draught by power-assisted systems
    • F23N3/082—Regulating air supply or draught by power-assisted systems using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/003—Systems for controlling combustion using detectors sensitive to combustion gas properties
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G2202/00—Combustion
    • F23G2202/10—Combustion in two or more stages
    • F23G2202/106—Combustion in two or more stages with recirculation of unburned solid or gaseous matter into combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G2206/00—Waste heat recuperation
    • F23G2206/10—Waste heat recuperation reintroducing the heat in the same process, e.g. for predrying
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G2206/00—Waste heat recuperation
    • F23G2206/20—Waste heat recuperation using the heat in association with another installation
    • F23G2206/203—Waste heat recuperation using the heat in association with another installation with a power/heat generating installation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G2207/00—Control
    • F23G2207/30—Oxidant supply
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G2900/00—Special features of, or arrangements for incinerators
    • F23G2900/00001—Exhaust gas recirculation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2217/00—Intercepting solids
    • F23J2217/10—Intercepting solids by filters
    • F23J2217/101—Baghouse type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/10—Catalytic reduction devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
    • F23L2900/07007—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber using specific ranges of oxygen percentage
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2221/00—Pretreatment or prehandling
    • F23N2221/12—Recycling exhaust gases
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/12—Heat utilisation in combustion or incineration of waste
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/32—Direct CO2 mitigation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Definitions

  • the present invention relates to an apparatus and a method for incinerating waste by recycling exhaust gas of an incinerator such that the exhaust gas can be mixed with oxygen. More particularly, the present invention relates to an apparatus and a method for incinerating waste, in which exhaust gas of an incinerator is recycled without being discharged to an exterior such that the exhaust gas can be reused for the waste combustion process, thereby reducing the amount of exhaust gas being discharged to the exterior, and in which waste is rapidly dried by means of remaining heat of recycle gas, so that the heat efficiency of the incinerator can be improved, and the recycle gas is mixed with oxygen during the waste combustion process, so that the oxygen enrichment rate is increased. Accordingly, the waste can be rapidly and completely burned because the waste is subject to high-temperature combustion with a low air ratio, so that the energy conversion efficiency of the incinerator can be maximized due to the increased combustion temperature.
  • a waste incinerating apparatus includes an incinerator for burning waste, a waste heat boiler for converting exhaust gas of the incinerator into energy by applying the high temperature to the exhaust gas, a reactor and a bag filter for removing harmful gas from exhaust gas that has passed through the waste heat boiler, and a stack for discharging clean gas to an atmosphere.
  • Such a waste incinerating apparatus receives excess air so as to perform the combustion process for waste.
  • the heat efficiency of the waste incinerating apparatus may be limited to a predetermined level, so that high-temperature combustion for the waste is very difficult.
  • the present invention has been made in view of the above- mentioned problems occurring in the prior art, and it is an object of the present invention to provide an apparatus and a method for incinerating waste by recycling exhaust gas of an incinerator such that the exhaust gas can be mixed with oxygen, wherein exhaust gas of the incinerator is recycled without being discharged to an exterior such that the exhaust gas can be reused for the waste combustion process, thereby reducing the amount of exhaust gas being discharged to the exterior, wherein waste is rapidly dried by means of remaining heat of recycle gas, so that the heat efficiency of the incinerator can be improved, wherein the recycle gas is mixed with oxygen during the waste combustion process, so that the oxygen enrichment rate is increased, wherein the waste can be rapidly and completely burned by allowing the waste to be subject to high-temperature combustion with a low air ratio such that the energy conversion efficiency of the incinerator can be maximized due to the increased combustion temperature, and wherein working expenses can be reduced by minimizing the amount medicines required for removing harmful gas.
  • ⁇ 20> method for incinerating waste by circulating exhaust gas in an incinerator comprising: an incineration process for burning waste by inputting the waste into first and second combustion chambers of an incinerator; a steam production process for producing steam to generate energy by feeding high-temperature recycle gas that has been generated through the incineration process into a waste boiler; a temperature reduction and harmful gas removal process for reducing a temperature of the recycle gas and removing harmful gas from the recycle gas by feeding the recycle gas into a semi-dry type alkali absorption reactor after the steam production process; a harmful material removal process for removing harmful materials from the recycle gas by feeding the recycle gas into a bag filter after the temperature reduction and harmful gas removal process; a recycle process for circulating the recycle gas into the first and second combustion chambers of the incinerator after the harmful material removal process; and an air supplement process for selectively supplying air to the recycle gas based on an amount of the recycle gas during the recycle process in order to burn the waste.
  • an incinerating apparatus for incinerating waste by circulating gas such that the gas is mixed with oxygen
  • the apparatus comprising: an incinerator provided at an upper end portion thereof with a hopper for feeding the waste, formed at an inner portion thereof with first and second combustion chambers and provided at a lower end portion thereof with an ash discharge port; a waste heat boiler installed at one side of the incinerator and connected to one side of the incinerator through a pipe in order to generate steam by using the recycle gas as a heat source; a reactor installed at one side of the waste heat boiler and connected to the waste heat boiler through a pipe in order to remove harmful gas contained in the recycle gas and to reduce a temperature of the recycle gas discharged from the waste heat boiler; a bag filter installed at one side of the reactor and connected to the reactor through a pipe, in which the bag filter is provided at an inner portion thereof with a filter so as to filter harmful materials contained in the recycle gas discharged from the reactor; a recycle unit including
  • gas generated during the waste combustion process is circulated and reused without being discharged to the exterior, thereby preventing environmental pollution.
  • FIG. 1 is a view illustrating the structure of a waste incinerating apparatus according to one embodiment of the present invention
  • FIG. 2 is a view illustrating the structure of a combustion device provided in a waste incinerating apparatus according to one embodiment of the present invention
  • FIG. 3 is a view illustrating the structure of a dryer provided in a waste incinerating apparatus according to one embodiment of the present invention
  • FIG. 4 is a view illustrating the structure of a central control panel used for controlling a waste incinerating apparatus according to one embodiment of the present invention! and ⁇ 42>
  • FIG. 5 is a block diagram illustrating the procedure for incinerating waste according to one embodiment of the present invention.
  • FIG. 1 is a view illustrating the structure of a waste incinerating apparatus according to one embodiment of the present invention
  • FIG. 2 is a view illustrating the structure of a combustion device provided in the waste incinerating apparatus according to one embodiment of the present invention
  • FIG. 3 is a view illustrating the structure of a dryer provided in the waste incinerating apparatus according to one embodiment of the present invention
  • FIG. 4 is a view illustrating the structure of the central control panel used for controlling the waste incinerating apparatus according to one embodiment of the present invention.
  • the incinerating apparatus 1 mainly includes an incinerator 10, a waste heat boiler 50, a reactor 60, a bag filter 70, a recycle unit 100, an air supplement unit 110, an oxygen feed unit 120, and a central control panel 150 for controlling the above elements.
  • the incinerator 10 is provided at an upper end portion thereof with a hopper 13 for feeding waste.
  • Combustion chambers 11 and 12 are formed in the incinerator 10 so as to incinerate waste introduced thereto through the hopper 13.
  • An ash discharge port 14 is formed at a lower end portion of the incinerator 10 so as to discharge waste ash to the exterior after the waste has been burned.
  • an outlet port 15 is formed at an upper portion of the combustion chambers 11 and 12 and is connected to the waste heat boiler 50 so as to discharge recycle gas generated during the waste combustion process.
  • the waste heat boiler 50 is installed at one side of the incinerator 10 and is connected to the outlet port 15 through a pipe 5a in order to generate steam by using the recycle gas as a heat source.
  • the recycle gas discharged from the incinerator 10 has the temperature of about 1200"C or more.
  • the steam generated by the waste heat boiler 50 is transferred to a steam tank 51 to operate a turbine power generator 52, so that the steam can be used as energy for generating electricity.
  • the recycle gas that has been cooled in the waste heat boiler 50 at the temperature of about 230°C or less may contain harmful materials, such as dust and impurities, so the harmful materials contained in the recycle gas must be reduced according to environmental standards when the recycle gas is discharged to the atmosphere. For this reason, recycle gas (exhaust gas) treatment equipment capable of removing HCl, SOx and dioxin must be prepared.
  • a reactor 60 and a bag filter 70 are employed as the recycle gas treatment equipment.
  • the reactor 60 includes a semi-dry type alkali absorption reactor, which is installed at one side of the waste heat boiler 50 and is connected to a gas discharge pipe 5b of the waste heat boiler 50 in order to remove harmful gas contained in the recycle gas and to reduce the temperature of the recycle gas discharged from the waste heat boiler 50 from 230°C to 200°C.
  • the recycle gas that has passed through the waste heat boiler 50 is introduced into the reactor 60 at the temperature of about 230°C , so that HCl and SOx may react with slacked lime (Ca(OH ⁇ ).
  • harmful acid gas contained in the recycle gas is completely removed by means of harmless neutralized salt CaCU or CaSOs. Water contained in slacked lime slurry is evaporated when it makes contact with the recycle gas, so that water is prevented from being collected at the lower portion of the reactor 60.
  • the reason for reducing the temperature of the recycle gas in the reactor 60 is to protect the bag filter 70 from the high temperature.
  • the bag filter 70 is installed at one side of the reactor 60 and is connected to a gas discharge pipe 5c.
  • a filter 71 is accommodated in the bag filter 70 so as to filter harmful materials such as dust or impurities contained in the recycle gas that has passed through the reactor 60.
  • the recycle unit 100 includes main feed pipes 101 and branch pipes 101a to 101d, which connect the bag filter 70 to the combustion chambers 11 and 12 so as to circulate the recycle gas from the bag filter 70 to the combustion chambers 11 and 12 of the incinerator 10.
  • the recycle unit 100 includes a blower 102 installed above the main feed pipes 101 and branch pipes 101a to 101d in order to blow the recycle gas.
  • an outlet part of the main feed pipe 101 branches into the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, and the after-combustion zone gas feed pipe 101c, which connect the main feed pipe 101 with the first combustion chamber 11.
  • the outlet part of the main feed pipe 101 also branches into the second combustion chamber gas feed pipe 101d, which connects the main feed pipe 101 with the second combustion chamber 12, and a recycle gas feed pipe lOle connecting the main feed pipe 101 with a dryer which will be described later.
  • the recycle gas is fed into the first and second combustion chambers 11 and 12 and the dryer 30 through the gas feed pipes 101a to lOle after the recycle gas has been circulated through the feed pipe 101.
  • the main feed pipe 101 and the branch pipes 101a to lOle include a recycle gas adjustment damper 115a, a gas adjustment damper 115b, an air adjustment damper 115c, a gas induce/feed adjustment damper 115d, a second combustion chamber gas feed adjustment damper 115e, a dry zone gas adjustment damper 115f, a combustion zone gas adjustment damper 115g, an after combustion zone gas adjustment damper 115h, a recycle gas feed adjustment damper 115i , and a first combustion chamber gas feed adjustment damper 115j , respectively.
  • the adjustment dampers 115a to 115j are preferably installed at inlet and outlet sides of the main feed pipes 101 and branch pipes 101a to lOle, and installed at positions where the blower 102 is installed.
  • the installation positions of the adjustment dampers 115a to 115j may vary depending on their purposes.
  • adjustment dampers 115k and 1151 are installed in pipes 5d and 5e, which connect the bag filter 70 with a catalyst deodorizer tower 80 and a stack 90, respectively, which will be described later in detail .
  • the blower 102 includes a guide blower 102b installed at an inlet side of the main feed pipe 101 so as to guide the recycle gas toward the main feed pipe 101 when the recycle gas is discharged from the bag filter 70; a first gas feed blower 102a installed at an outlet side of the main feed pipe 101 so as to feed the recycle gas into the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, and the recycle gas feed pipe lOle! and a second gas feed blower 102c installed in the second combustion chamber gas feed pipe 101d so as to feed the recycle gas into the second combustion chamber 12.
  • the air supplement unit 110 is connected to the main feed pipe 101 so as to supply air according to the amount of recycle gas that passes through the main feed pipe 101.
  • the air supplement unit 110 is installed between the main feed pipe 101 and an air inlet pipe 111 so as. to receive air from an exterior when the amount of recycle gas is insufficient.
  • the air feed adjustment damper 115c is installed in the air inlet pipe 111.
  • the amount of recycle gas that passes through the main feed pipe 101 is detected by means of a gas detecting sensor 131 and a recycle gas state detecting device 151, which will be described later, and the detected data are transmitted to the central control panel 150, so that the central control panel 150 adjusts the operation of the air feed adjustment damper 115c based on the detected data in such a manner that a predetermined amount of air required for the combustion process can be fed into the combustion chambers 11 and 12.
  • the combustion process must be carried out by feeding oxygen into gas in order to use the recycle gas for the purpose of waste combustion.
  • the oxygen feed unit 120 is communicated with the feed pipes 101a to 101d so as to feed high-purity oxygen to the recycle gas selectively mixed with air.
  • the oxygen feed unit 120 includes an oxygen reservoir tank 122 and an oxygen generator 123 connected to the oxygen generator 123 in order to feed oxygen into the oxygen reservoir tank 122.
  • the oxygen reservoir tank 122 is communicated with a dry zone oxygen feed pipe 121a, the combustion zone oxygen feed pipe 121b, an after- combustion zone oxygen feed pipe 121c, and a second combustion chamber oxygen feed pipe 121d, which are connected to the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, and the second combustion chamber gas feed pipe 101d, respectively.
  • a dry zone oxygen feed control valve 124a a combustion zone oxygen feed control valve 124b, an after-combustion zone oxygen feed control valve 124c, and a second combustion chamber oxygen feed control valve 124d are installed in the oxygen feed pipes 121a to 12Id, respectively.
  • high-purity oxygen is fed from the oxygen generator 123 and the oxygen reservoir 122 to a dry zone mixing chamber 21a, a combustion zone mixing chamber 21b, and an after-combustion zone mixing chamber 21c of a combustion unit 20 and the second combustion chamber gas feed pipe 101d through the oxygen feed pipes 121a to 121d and the oxygen feed control valves 124a to 124d.
  • the recycle gas is mixed with the high-purity oxygen in the mixing chambers 21a to 21c in such a manner that the recycle gas has an oxygen rate of 21% or more (the oxygen rate may increase depending on combustion conditions) when the recycle gas is fed into the first and second combustion chambers 11 and 12.
  • the incinerator 10 includes the first combustion chamber 11 used for burning waste and the second combustion chamber 12 installed above the first combustion chamber 11 so as to burn gas generated after the waste combustion process.
  • the first and second combustion chambers 11 and 12 receive the recycle gas containing at least 21% of oxygen from the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, the after-combustion zone mixing chamber 21c, and the second combustion chamber gas feed pipe 101d so as to use the recycle gas for the combustion process.
  • the combustion unit 20 is installed on the bottom of the first combustion chamber 11 such that the combustion unit 20 can be connected to the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, the dry zone oxygen feed pipe 121a, the combustion zone oxygen feed pipe 121b, and the after-combustion zone oxygen feed pipe 121c, respectively.
  • the waste combustion process is performed by feeding the recycle gas mixed with pure oxygen into the first combustion chamber 11, waste is burned while being stirred and moved in the form of a wave pattern by means of the combustion unit 20.
  • the combustion unit 20 is installed on the bottom of the first combustion chamber 11 in the step structure (for example, a three-step combustion unit is shown in FIG. 1).
  • the combustion unit 20 consists of a dry zone nozzle/grate 20a, a combustion zone nozzle/grate 20b, and an after- combustion zone nozzle/grate 20c, which are sequentially installed from the upper portion of the combustion unit 20.
  • Such a combustion unit 20 includes the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, which are connected to the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, the dry zone oxygen feed pipe 121a, the combustion zone oxygen feed pipe 121b, and the after-combustion zone oxygen feed pipe 121c in order to mix the recycle gas with high-purity oxygen; grates 23 spaced apart from the mixing chambers 21a to 21c by a predetermined distance and formed at inner portions thereof with pressure chambers 24 in which a plurality of nozzles 25 are installed at one side of each pressure chamber 24; and pressure adjustment valves 22 installed between the mixing chambers 21a to 21c and pressure chambers 24 so as to adjust pressure of gas introduced into each pressure
  • the combustion unit 20 sequentially supplies gas through the pressure chambers 24 and nozzles 25 in the order of a, b, c, d, e, f and g by adjusting the pressure adjustment valves 22 while varying the gas feeding speed in a range of 50m/sec to 150m/sec, thereby performing the combustion process while stirring and moving waste in the form of a wave pattern.
  • the dryer 30 is installed at the upstream of the combustion chambers 11 and 12 formed in the incinerator 10 so as to rapidly dry the waste.
  • the dryer 30 includes a gas feed pressure chamber 31 installed at the sidewall of the incinerator 10 and connected to the recycle gas feed pipe lOle so as to receive the recycle gas and a dry nozzle 32 coupled to one side of the gas feed pressure chamber 31 so as to spray the recycle gas toward the waste.
  • a plurality of sensors 130 are installed in a region where the recycle gas is mixed with air, that is, the sensors 130 are provided in a predetermined portion of the main feed pipe 101 coupled with the air inlet pipe 111 in order to detect the amount of recycle gas selectively mixed with air, the temperature, and the amount of oxygen contained in the recycle gas.
  • the sensors 130 consist of a gas detecting sensor 131 for detecting an amount of gas, a temperature detecting sensor 132 and an oxygen detecting sensor 133 for detecting an amount of oxygen contained in the gas.
  • the sensors 130 send data related to the flow of detected gas to the recycle gas state detecting device 151.
  • the central control panel 150 receives data from the recycle gas state detecting device 151 and sends signals to corresponding devices of the incinerating apparatus 1 in order to control the devices.
  • Each device of the incinerating apparatus 1 is provided with a temperature controller 156 for receiving data related to the temperature of the recycle gas used for the combustion process and the temperature of each device, a first combustion chamber infrared temperature sensor 140a installed in the first combustion chamber 11 of the incinerator 10, a second combustion chamber infrared temperature sensor 140b installed in the second combustion chamber 12 of the incinerator 10, a first temperature gauge 140c provided in the waste heat boiler 50, a second temperature gauge 14Od provided in the gas discharge pipe 5b of the waste heat boiler 50, a third temperature gauge 14Oe provided in the gas discharge pipe 5c of the reactor 60, and temperature gauges 14Of to 14Oh provided in the bag filter 70.
  • the combustion temperature condition is input into the central control panel 150 so as to control the temperature of each device.
  • temperature data of the infrared temperature sensors 140a and 140b and the temperature gauges 140c to 140h are transmitted to the central control panel 150, so that the controller controls the devices based on the temperature, thereby maintaining optimal combustion conditions.
  • the first and second combustion chamber infrared sensors 140a and 140b which are installed in the first and second combustion chambers 11 and 12, respectively, may serve as sensors of a combustion control system.
  • the first and second combustion chamber infrared sensors 140a and 140b have a rapid response speed, so that they can instantly measure the combustion temperature, thereby realizing stable combustion, stabilizing the amount of water being evaporated, and improving the characteristics of the recycle gas.
  • first and second auxiliary burners 11a and 12a are installed in the first and second combustion chambers 11 and 12, respectively, in order to assist the combustion process.
  • An internal pressure adjustment device 135 is installed in the pipe 5a provided between the second combustion chamber 12 of the incinerator 10 and the waste heat boiler 50 in order to check and adjust pressure of the above system for the purpose of stable combustion.
  • the catalyst deodorizer tower 80 branches from the pipe 5d at a start point of the main feed pipe 101 so as to purify the recycle gas, and the stack 90 is installed at one side of the catalyst deodorizer tower 80 while being connected to the catalyst deodorizer tower 80 through the pipe 5e in order to discharge the purified gas to the exterior.
  • the catalyst deodorizer tower 80 includes an SCR (selective catalyst reduction) tower containing the catalyst including about 65 weight percent of T1O2, V 2 O 5 , WO 3 , etc.
  • the catalyst consists of three layers. The first layer is used for removing NOx and the second and third layers are used for removing dioxin by dissolving dioxin into CO2, H 2 O, HCl, etc.
  • the recycle gas discharged from the bag filter 70 is introduced into the main feed pipe 101 by means of the recycle gas feed adjustment damper 115a, the gas adjustment damper 115b, and the guide blower 102b such that the recycle gas can be used for the combustion process.
  • the remaining recycle gas is introduced into the catalyst deodorizer tower 80 by means of a guide blower 85 and the adjustment dampers 115k and 1151, which are installed in pipes 5d and 5e connected to the catalyst deodorizer tower 80 and the stack 90, respectively, and the remaining recycle gas is discharged to the exterior through the stack 90 after being purified by the catalyst deodorizer tower 80.
  • FIG. 4 is a view illustrating the structure of the central control panel 150 for controlling the incinerating apparatus according to the present invention. The following description will be focused on the important parts of the central control panel 150.
  • the central control panel 150 receives data from the recycle gas state detecting device 151, an oxygen controller control unit 152, a gas controller 153, a damper controller 154, a package device controller 155, and the temperature controller 156 so as to control the above devices by transmitting signals to the devices.
  • the recycle gas state detecting device 151 detects the amount of gas, the temperature and the amount of oxygen contained in the gas from the gas detecting sensor 131, the temperature detecting sensor 132, and the oxygen detecting sensor 133, and then sends data thereof to the central control panel 150.
  • the oxygen controller control unit 152 receives data related to the amount of oxygen from the oxygen detecting sensor 133. In this state, if oxygen generated from the oxygen generator 123 is fed into the oxygen reservoir tank 122, the oxygen controller control unit 152 controls the dry zone oxygen feed control valve 124a, the combustion zone oxygen feed control valve 124b, the after-combustion zone oxygen feed control valve 124c, and the second combustion chamber oxygen feed control valve 124d in such a manner that a predetermined amount of oxygen that has been preset in the controller can be fed into the gas feed pressure chamber 31 of the dryer 30, the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c.
  • the gas controller 153 controls the pressure adjustment valve 22 with a predetermined value that has been preset in the central control panel 150, when the recycle gas and oxygen, which have been mixed in the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, are fed into the dry zone nozzle/grate 20a, the combustion zone nozzle/grate 20b, and the after-combustion zone nozzle/grate 20c in such a manner that the recycle gas and oxygen can be fed at the gas feeding speed in a range of 50m/sec to 150m/sec, so that the combustion process can be performed while stirring and moving waste in the form of a wave pattern.
  • the damper controller 154 controls the adjustment dampers 115a to 1151 based on program signals, which have been present in the central control panel 150 that receives data related to the gas flow from the gas detecting sensor 131, the temperature detecting sensor 132, and the oxygen detecting sensor 133.
  • the package device controller 155 controls a hydraulic device, an air compressor, a truck scale, a waste crane, a waste crusher, a gas discharge inspection device, a deodorizer tower, etc.
  • the temperature controller 156 receives data related to the temperature of the recycle gas and devices from the infrared temperature sensors 140a and 140b and the temperature gauges 140c to 14Oh, and then sends the temperature data to the central control panel 150 such that the combustion process can be performed with optimal combustion conditions.
  • the first gas feed blower 102a and adjustment dampers 115f to 115j are driven before waste is input into the first and second combustion chambers 11 and 12 in order to rise the internal temperature of the first and second combustion chambers 11 and 12 to a level of 600°C or above.
  • the air adjustment damper 115c of the air inlet pipe 111 is opened so as to inject air into the first and second combustion chambers 11 and 12.
  • auxiliary burners 11a and 12a of the first and second combustion chambers 11 and 12 are operated, so that the internal temperature of the first and second combustion chambers 11 and 12 rise. In this state, waste is input into the hopper 13.
  • ⁇ i7i> The waste that has been input into the hopper 13 is moved in the form of a wave pattern while continuously passing through the dry zone nozzle/grate 20a, the combustion zone nozzle/grate 20b, and the after- combustion zone nozzle/grate 20c, so that the waste is incinerated or burned. .
  • ash is discharged through the ash discharge port 14.
  • the temperature of recycle gas discharged through the outlet port 15 of the incinerator 10 is about 1200 ° C or above.
  • Such a high-temperature recycle gas is moved into the waste boiler 50 and the waste boiler 50 uses the recycle gas as a heat source in order to generate steam.
  • the steam is transferred to the steam tank 51, so that a turbine generator 52 is operated, thereby producing electricity and energy to be used.
  • the recycle gas discharged through the waste boiler 50 has a temperature of about 230 ° C, and is moved into the semi-dry type alkali absorption reactor 60.
  • the temperature of the recycle gas is reduced from 230 °C to 200°C at the semi-dry type alkali absorption reactor 60 and harmful gas contained in the recycle gas is removed. After that, the recycle gas is transferred to the bag filter 70.
  • the semi-dry type alkali absorption reactor 60 does not use a medicine, but only uses water to move the recycle gas to the bag filter 70 by reducing the temperature of the recycle gas.
  • the semi-dry type alkali absorption reactor 60 uses the medicine together with water to remove the harmful gas from the recycle gas only when it is necessary to discharge the remaining recycle gas to the atmosphere. Thus, the amount of medicines can be reduced in use.
  • the recycle gas that has been discharged from the bag filter 70 is introduced into the main gas feed pipe 101 through the recycle gas feed adjustment damper 115a, the guide blower 102b, and the gas adjustment damper 115b.
  • the damper controller 154 controls the recycle gas adjustment damper 115a such that a predetermined amount of recycle gas can be fed into the main feed pipe 101.
  • the first gas feed blower 102a and the first combustion chamber gas feed adjustment damper 115j are operated, so that the recycle gas introduced into the main feed pipe 101 is fed into the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, and the after-combustion zone gas feed pipe 101c.
  • the dry zone gas adjustment damper 115f, the combustion zone gas adjustment damper 115g, and the after combustion zone gas adjustment damper 115h are operated so that the recycle gas that has been fed into the gas feed pipes 101a to 101c is introduced into the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, respectively.
  • the gas detecting sensor 131, the temperature detecting sensor 132, and the oxygen detecting sensor 133 detect the amount of recycle gas, the temperature, and the amount of oxygen contained in gas, respectively, and then send the data related to the state of the gas flow to the recycle gas state detecting device 151. Accordingly, the central control panel 150 sends signals to each device based on the data received in the recycle gas state detecting device 151, thereby controlling the devices in such a manner that gas suitable for the combustion process can be obtained by mixing the recycle gas with oxygen.
  • the amount of recycle gas is detected by the gas detecting sensor 131 and the air adjustment damper 115c is controlled based on the amount of recycle gas detected by the gas detecting sensor 131 in such a manner that air can be mixed with the recycle gas if the amount of recycle gas is insufficient for the combustion process.
  • oxygen in order to reuse the recycle gas that has been fed into the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, oxygen must be mixed with the recycle gas. That is, not only is air containing 21% of oxygen added to the recycle gas, but also air having an increased oxygen enrichment rate above 21% must be provided to the recycle gas so as to obtain high- temperature combustion at a low air ratio.
  • the oxygen detecting sensor 133 detects the amount of oxygen contained in the recycle gas and then sends data to the oxygen controller control unit 152.
  • the oxygen controller control unit 152 controls the dry zone oxygen feed control valve 124a, the combustion zone oxygen feed control valve 124b, and the after-combustion zone oxygen feed control valve 124c according to the amount of oxygen contained in the recycle gas, thereby feeding a predetermined amount of oxygen to the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, respectively.
  • the oxygen is mixed with the recycle gas, which has been fed into the mixing chambers 21a to 21c, during the combustion process.
  • the recycle gas that has been fed into the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c is mixed with high-purity oxygen such that the recycle gas can contain 21% or more of oxygen, in which the oxygen rate may vary depending on the combustion condition.
  • the recycle gas mixed with the oxygen is fed into the dry zone nozzle/grate 20a, the combustion zone nozzle/grate 20b, and the after-combustion zone nozzle/grate 20c.
  • the pressure adjustment valve 22 is controlled according to data, which are preset in the central control panel 150, in such a manner that the recycle gas can be fed in the form of a wave pattern with a predetermined pressure. Therefore, waste can be stirred and burned while being moved in the form of the wave pattern.
  • the combustion unit 20 sequentially supplies the recycle gas in the order of a, b, c, d, e, f and g while varying the gas feeding speed in a range of 50m/sec to 150m/sec, thereby performing the combustion process while sequentially stirring and moving waste in the form of a wave pattern.
  • the second combustion chamber oxygen feed control valve 124d feeds high-purity oxygen to the second chamber 12 in accordance with the amount of recycle gas fed into the second combustion chamber 12.
  • the dryer 30 installed at the downstream side of the hopper 13 receives the recycle gas from the recycle gas feed pipe lOle and the recycle gas feed adjustment damper 115i in order to dry waste by applying high-temperature gas to the waste.
  • the recycle gas feed pipe lOle and the recycle gas feed adjustment damper 115i receives the recycle gas from the recycle gas feed pipe lOle and the recycle gas feed adjustment damper 115i in order to dry waste by applying high-temperature gas to the waste.
  • water contained in the waste is removed, thereby improving the calorific value of waste and raising the heat recovery efficiency.
  • FIG. 5 is a block diagram illustrating the procedure for incinerating waste according to one embodiment of the present invention.
  • the procedure for incinerating waste according to one embodiment of the present invention mainly includes an incineration process 201, a steam production process 202, a harmful gas removal process 203, a harmful material removal process 204, a recycle process 205, an air supplement process 206, and an oxygen feed process 206a.
  • the incineration process 201 refers to a process for burning waste by inputting the waste into the first and second combustion chambers 11 and 12 of the incinerator 10. That is, the waste that has been input into the first and second combustion chambers 11 and 12 through the hopper 13 of the incinerator 10 is burned in the first and second combustion chambers 11 and 12. Waste ash that has been produced after the incineration process is discharged to the exterior through the ash discharge port 14, and the recycle gas that has been generated during the incineration process is discharged through the outlet port 15 for the next steam production process 202.
  • the incineration process is divided into a first incineration process 201b performed in the first combustion chamber 11 of the incinerator 10, and a second incineration process 201c performed in the second combustion chamber 12 with respect to gas generated during the first incineration process 201b.
  • the recycle gas mixed with high-purity oxygen is used during the first and second incineration processes 201b and 201c.
  • a drying process 201a is performed before the waste is input into the first and second combustion chambers 11 and 12 of the incinerator 10 so as to dry the waste by using the recycle gas having the high temperature.
  • the drying process 201a is performed prior to the first incineration process 201b so as to dry the waste by applying the recycle gas to the waste being inputted into the first combustion chamber 11 through the hopper 13. Since the waste is dried, the incineration process can be performed at a high speed so that the calorific value of waste and the heat recovery efficiency can be improved.
  • the steam production process 202 refers to a process for producing steam to generate energy by feeding the high-temperature recycle gas that has been generated through the incineration process 201 into the waste boiler 50.
  • the high-temperature recycle gas that has been discharged from the incinerator 10 is fed into the waste boiler 50 so that the waste boiler 50 produces steam by using the high-temperature recycle gas.
  • This steam is fed into the steam tank 51, thereby driving the turbine generator 52 to produce electricity.
  • the steam generated from the waste boiler 50 is transferred to various places to generate energy, such as electricity.
  • the temperature reduction and harmful gas removal process 203 refers to a process for reducing the temperature of the recycle gas and removing harmful gas from the recycle gas by feeding the recycle gas into the semi-dry type alkali absorption reactor 60 after the steam production process 202.
  • the recycle gas has the temperature of about 230°C when the recycle gas is discharged from the waste boiler 50.
  • the temperature of the recycle gas is reduced to about 200°C in the reactor 60. Accordingly, it is possible to protect the bag filter 70 from the high temperature during the next harmful material removal process 204.
  • the semi-dry type alkali absorption reactor 60 does not use a medicine, but only uses water to move the recycle gas to the bag filter 70 by reducing the temperature of the recycle gas.
  • the semi-dry type alkali absorption reactor 60 uses the medicine together with water to remove the harmful gas from the recycle gas only when it is necessary to discharge the remaining recycle gas to the atmosphere. Thus, the amount of medicines can be reduced in use.
  • the harmful material removal process 204 refers to a process for removing harmful materials from the recycle gas by feeding the recycle gas into the bag filter 70 after the temperature reduction and harmful gas removal process 203.
  • the recycle process 205 refers to a process for circulating the recycle gas into the first and second combustion chambers 11 and 12 of the incinerator 10 after the harmful material removal process 204.
  • the air supplement process 206 refers to a process for selectively supplying air to the recycle gas during the recycle process 205 in order to burn the waste.
  • the oxygen feed process 206a refers to a process for supplying oxygen having purity of 90% or more (preferably, 95% or more) to the recycle gas, which has been mixed with air through the air supplement process 206, during the recycle process 205.
  • a sensor 130 is installed in the main feed pipe 101 at a position where the recycle gas is mixed with air, thereby detecting the amount of oxygen contained in the recycle gas. If it is detected that the amount of oxygen in the recycle gas is insufficient, a predetermined amount of oxygen is fed into the recycle gas for the purpose of combustion.
  • the recycle gas it is preferred for the recycle gas to have the oxygen rate of about 21% or more. If the oxygen rate is further increased by 5% to 6% from 21%, high-temperature combustion can be realized with a low-air ratio.
  • Table 1 shows data representing the difference between the conventional incinerating apparatus and the incinerating apparatus according to the present invention.
  • Table 1 is obtained from various waste materials shown in Table 2 by mixing high-purity oxygen with the recycle gas on the basis of following conditions ⁇
  • ⁇ 326> * is an oxygen enrichment rate in gas.
  • ⁇ 339> 40,125 Nm 3 /hr (amount of gas used in the present invention)
  • ⁇ 389> ( ⁇ /(l-n)) x W R x ( 8,100 x n + R A x t A )
  • ⁇ 4ii> (401.94 - 361.30)/(l,100 - 1,000)

Abstract

Disclosed are an apparatus and a method for incinerating waste. Exhaust gas of an incinerator 10 is recycled without being discharged to an exterior. The incinerator 10 has a hopper 13 for feeding the waste, and includes first and second combustion chambers 11 and 12. A waste heat boiler 50 is installed at one side of the incinerator 10. A reactor 60 is installed at one side of the waste heat boiler. A bag filter 70 is installed at one side of the reactor. A recycle unit 100 includes a main feed pipe 101 and branch pipes 101a to 101d, which connect the bag filter to the first and second combustion chambers. The recycle unit 100 has a blower 102 installed above the main feed pipe 101 and branch pipes. An air supplement unit 110 is connected to the main feed pipe 101.

Description

[DESCRIPTION] [Invention Title]
APPARATUS AND METHOD FOR INCINERATING WASTE BY RECYCLING EXHAUST GAS OF INCINERATOR SUCH THAT EXHAUST GAS IS MIXED WITH OXYGEN
[Technical Field]
<i> The present invention relates to an apparatus and a method for incinerating waste by recycling exhaust gas of an incinerator such that the exhaust gas can be mixed with oxygen. More particularly, the present invention relates to an apparatus and a method for incinerating waste, in which exhaust gas of an incinerator is recycled without being discharged to an exterior such that the exhaust gas can be reused for the waste combustion process, thereby reducing the amount of exhaust gas being discharged to the exterior, and in which waste is rapidly dried by means of remaining heat of recycle gas, so that the heat efficiency of the incinerator can be improved, and the recycle gas is mixed with oxygen during the waste combustion process, so that the oxygen enrichment rate is increased. Accordingly, the waste can be rapidly and completely burned because the waste is subject to high-temperature combustion with a low air ratio, so that the energy conversion efficiency of the incinerator can be maximized due to the increased combustion temperature.
<3>
[Background Art]
<4> In general, a waste incinerating apparatus includes an incinerator for burning waste, a waste heat boiler for converting exhaust gas of the incinerator into energy by applying the high temperature to the exhaust gas, a reactor and a bag filter for removing harmful gas from exhaust gas that has passed through the waste heat boiler, and a stack for discharging clean gas to an atmosphere.
<6> Such a waste incinerating apparatus receives excess air so as to perform the combustion process for waste. However, if the waste contains a great quantity of water, the heat efficiency of the waste incinerating apparatus may be limited to a predetermined level, so that high-temperature combustion for the waste is very difficult.
<8> In addition, medicines are used in order to remove harmful gas from exhaust gas generated during the combustion process for the waste, but it is limited to convert harmful gas into clean gas by using medicines. Further, since slacked lime, activated carbon, ammonium, etc., are used as medicines, the working expenses may increase.
<io> In the meantime, environmental problems have recently become serious and disputes related to environmental pollution increasingly occur day by day. In this regard, conflictions between people and the government and/or between local provinces seriously occur at all parts of the country in relation to the location, construction and operation of waste treatment facilities.
<12> Conventionally, harmful gas and harmful materials contained in the exhaust gas, which is generated during the combustion process for waste, are somewhat removed when the exhaust gas is discharged to the exterior. However, the remaining parts of harmful gas and harmful materials discharged to the exterior together with the exhaust gas may cause environmental pollution.
<14>
[Disclosure]
[Technical Problem]
<i5> Therefore, the present invention has been made in view of the above- mentioned problems occurring in the prior art, and it is an object of the present invention to provide an apparatus and a method for incinerating waste by recycling exhaust gas of an incinerator such that the exhaust gas can be mixed with oxygen, wherein exhaust gas of the incinerator is recycled without being discharged to an exterior such that the exhaust gas can be reused for the waste combustion process, thereby reducing the amount of exhaust gas being discharged to the exterior, wherein waste is rapidly dried by means of remaining heat of recycle gas, so that the heat efficiency of the incinerator can be improved, wherein the recycle gas is mixed with oxygen during the waste combustion process, so that the oxygen enrichment rate is increased, wherein the waste can be rapidly and completely burned by allowing the waste to be subject to high-temperature combustion with a low air ratio such that the energy conversion efficiency of the incinerator can be maximized due to the increased combustion temperature, and wherein working expenses can be reduced by minimizing the amount medicines required for removing harmful gas.
<17>
[Technical Solution]
<i8> In order to accomplish the above object, according one aspect of the present invention, there is provided a
<20> method for incinerating waste by circulating exhaust gas in an incinerator, the method comprising: an incineration process for burning waste by inputting the waste into first and second combustion chambers of an incinerator; a steam production process for producing steam to generate energy by feeding high-temperature recycle gas that has been generated through the incineration process into a waste boiler; a temperature reduction and harmful gas removal process for reducing a temperature of the recycle gas and removing harmful gas from the recycle gas by feeding the recycle gas into a semi-dry type alkali absorption reactor after the steam production process; a harmful material removal process for removing harmful materials from the recycle gas by feeding the recycle gas into a bag filter after the temperature reduction and harmful gas removal process; a recycle process for circulating the recycle gas into the first and second combustion chambers of the incinerator after the harmful material removal process; and an air supplement process for selectively supplying air to the recycle gas based on an amount of the recycle gas during the recycle process in order to burn the waste.
<22> According to another aspect of the present invention, there is provided an incinerating apparatus for incinerating waste by circulating gas such that the gas is mixed with oxygen, the apparatus comprising: an incinerator provided at an upper end portion thereof with a hopper for feeding the waste, formed at an inner portion thereof with first and second combustion chambers and provided at a lower end portion thereof with an ash discharge port; a waste heat boiler installed at one side of the incinerator and connected to one side of the incinerator through a pipe in order to generate steam by using the recycle gas as a heat source; a reactor installed at one side of the waste heat boiler and connected to the waste heat boiler through a pipe in order to remove harmful gas contained in the recycle gas and to reduce a temperature of the recycle gas discharged from the waste heat boiler; a bag filter installed at one side of the reactor and connected to the reactor through a pipe, in which the bag filter is provided at an inner portion thereof with a filter so as to filter harmful materials contained in the recycle gas discharged from the reactor; a recycle unit including a main feed pipe and branch pipes, which connect the bag filter to the first and second combustion chambers so as to circulate the recycle gas from the bag filter to the first and second combustion chambers of the incinerator, and a blower installed above the main feed pipe and branch pipes in order to blow the recycle gas; and an air supplement unit connected to the main feed pipe so as to supply air according to the amount of the recycle gas that passes through the main feed pipe.
<24>
[Advantageous Effects]
<25> As can be seen from the foregoing, according to the present invention, gas generated during the waste combustion process is circulated and reused without being discharged to the exterior, thereby preventing environmental pollution.
<27> In addition, the remaining heat of the recycle gas is retrieved so as to rapidly dry the waste, so that the heat vale of the waste can be improved. At the same time, high-purity oxygen is mixed with the recycle gas during the combustion process, so that the oxygen enrichment rate can be improved, thereby enabling the high-temperature combustion at a low air ratio. Thus, the energy conversion efficiency of the incinerating apparatus can be maximized, which is advantageous in view of economy.
<29> Furthermore, since the recycle gas is used for the combustion process, the amount of medicines, which are used for removing harmful gas, can be reduced, so that the working expenses can be saved.
<31>
[Description of Drawings] <32> The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: <34> FIG. 1 is a view illustrating the structure of a waste incinerating apparatus according to one embodiment of the present invention; <36> FIG. 2 is a view illustrating the structure of a combustion device provided in a waste incinerating apparatus according to one embodiment of the present invention; <38> FIG. 3 is a view illustrating the structure of a dryer provided in a waste incinerating apparatus according to one embodiment of the present invention; <40> FIG. 4 is a view illustrating the structure of a central control panel used for controlling a waste incinerating apparatus according to one embodiment of the present invention! and <42> FIG. 5 is a block diagram illustrating the procedure for incinerating waste according to one embodiment of the present invention.
<44>
[Mode for Invention] <45> Reference will now be made in detail to the preferred embodiments of the present invention. <47> In the following description, the elements and functions thereof identical to those of the prior art will not be described in detail in order to avoid redundancy. <49> FIG. 1 is a view illustrating the structure of a waste incinerating apparatus according to one embodiment of the present invention, FIG. 2 is a view illustrating the structure of a combustion device provided in the waste incinerating apparatus according to one embodiment of the present invention, FIG. 3 is a view illustrating the structure of a dryer provided in the waste incinerating apparatus according to one embodiment of the present invention, and FIG. 4 is a view illustrating the structure of the central control panel used for controlling the waste incinerating apparatus according to one embodiment of the present invention.
<5i> Prior to explaining the present invention, it should be noted that all of exhaust gas generated during the waste combustion process is recycled so that the exhaust gas is called "recycle gas."
<53> The incinerating apparatus 1 according to the present invention mainly includes an incinerator 10, a waste heat boiler 50, a reactor 60, a bag filter 70, a recycle unit 100, an air supplement unit 110, an oxygen feed unit 120, and a central control panel 150 for controlling the above elements.
<55> The incinerator 10 is provided at an upper end portion thereof with a hopper 13 for feeding waste. Combustion chambers 11 and 12 are formed in the incinerator 10 so as to incinerate waste introduced thereto through the hopper 13. An ash discharge port 14 is formed at a lower end portion of the incinerator 10 so as to discharge waste ash to the exterior after the waste has been burned.
<57> In addition, an outlet port 15 is formed at an upper portion of the combustion chambers 11 and 12 and is connected to the waste heat boiler 50 so as to discharge recycle gas generated during the waste combustion process.
<59> The waste heat boiler 50 is installed at one side of the incinerator 10 and is connected to the outlet port 15 through a pipe 5a in order to generate steam by using the recycle gas as a heat source. The recycle gas discharged from the incinerator 10 has the temperature of about 1200"C or more. The steam generated by the waste heat boiler 50 is transferred to a steam tank 51 to operate a turbine power generator 52, so that the steam can be used as energy for generating electricity. <6i> The recycle gas that has been cooled in the waste heat boiler 50 at the temperature of about 230°C or less may contain harmful materials, such as dust and impurities, so the harmful materials contained in the recycle gas must be reduced according to environmental standards when the recycle gas is discharged to the atmosphere. For this reason, recycle gas (exhaust gas) treatment equipment capable of removing HCl, SOx and dioxin must be prepared. According to the present invention, a reactor 60 and a bag filter 70 are employed as the recycle gas treatment equipment.
<63> The reactor 60 includes a semi-dry type alkali absorption reactor, which is installed at one side of the waste heat boiler 50 and is connected to a gas discharge pipe 5b of the waste heat boiler 50 in order to remove harmful gas contained in the recycle gas and to reduce the temperature of the recycle gas discharged from the waste heat boiler 50 from 230°C to 200°C.
<65> The recycle gas that has passed through the waste heat boiler 50 is introduced into the reactor 60 at the temperature of about 230°C , so that HCl and SOx may react with slacked lime (Ca(OH^). In addition, harmful acid gas contained in the recycle gas is completely removed by means of harmless neutralized salt CaCU or CaSOs. Water contained in slacked lime slurry is evaporated when it makes contact with the recycle gas, so that water is prevented from being collected at the lower portion of the reactor 60.
<67> During the reaction process in the reactor 60, the temperature of the recycle gas falls down to a level suitable for the operation of the bag filter 70, so that dioxin becomes liquid droplets and is prevented from being reproduced. Accordingly, harmful acid gas can be effectively removed. Meanwhile, fly ash and neutralized salt are collected in the lower portion of the reactor and then transferred to recycle equipment.
<69> The reason for reducing the temperature of the recycle gas in the reactor 60 is to protect the bag filter 70 from the high temperature.
<7i> In addition, the bag filter 70 is installed at one side of the reactor 60 and is connected to a gas discharge pipe 5c. A filter 71 is accommodated in the bag filter 70 so as to filter harmful materials such as dust or impurities contained in the recycle gas that has passed through the reactor 60.
<73> Since the waste heat boiler 50, the reactor 60, and the bag filter 70 are generally known in the art, detailed description thereof will be omitted here.
<75> The recycle unit 100 includes main feed pipes 101 and branch pipes 101a to 101d, which connect the bag filter 70 to the combustion chambers 11 and 12 so as to circulate the recycle gas from the bag filter 70 to the combustion chambers 11 and 12 of the incinerator 10. In addition, the recycle unit 100 includes a blower 102 installed above the main feed pipes 101 and branch pipes 101a to 101d in order to blow the recycle gas.
<77> Here, an outlet part of the main feed pipe 101 branches into the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, and the after-combustion zone gas feed pipe 101c, which connect the main feed pipe 101 with the first combustion chamber 11. In addition, the outlet part of the main feed pipe 101 also branches into the second combustion chamber gas feed pipe 101d, which connects the main feed pipe 101 with the second combustion chamber 12, and a recycle gas feed pipe lOle connecting the main feed pipe 101 with a dryer which will be described later.
<79> Accordingly, the recycle gas is fed into the first and second combustion chambers 11 and 12 and the dryer 30 through the gas feed pipes 101a to lOle after the recycle gas has been circulated through the feed pipe 101.
<8i> In order to precisely adjust the flow rate of the recycle gas that passes through the main feed pipe 101 and branch pipes 101a to lOle, the main feed pipe 101 and the branch pipes 101a to lOle include a recycle gas adjustment damper 115a, a gas adjustment damper 115b, an air adjustment damper 115c, a gas induce/feed adjustment damper 115d, a second combustion chamber gas feed adjustment damper 115e, a dry zone gas adjustment damper 115f, a combustion zone gas adjustment damper 115g, an after combustion zone gas adjustment damper 115h, a recycle gas feed adjustment damper 115i , and a first combustion chamber gas feed adjustment damper 115j , respectively.
<83> As shown in FIG. 1, the adjustment dampers 115a to 115j are preferably installed at inlet and outlet sides of the main feed pipes 101 and branch pipes 101a to lOle, and installed at positions where the blower 102 is installed. However, the installation positions of the adjustment dampers 115a to 115j may vary depending on their purposes.
<85> In the meantime, adjustment dampers 115k and 1151 are installed in pipes 5d and 5e, which connect the bag filter 70 with a catalyst deodorizer tower 80 and a stack 90, respectively, which will be described later in detail .
<87> In addition, the blower 102 includes a guide blower 102b installed at an inlet side of the main feed pipe 101 so as to guide the recycle gas toward the main feed pipe 101 when the recycle gas is discharged from the bag filter 70; a first gas feed blower 102a installed at an outlet side of the main feed pipe 101 so as to feed the recycle gas into the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, and the recycle gas feed pipe lOle! and a second gas feed blower 102c installed in the second combustion chamber gas feed pipe 101d so as to feed the recycle gas into the second combustion chamber 12.
<89> In addition, the air supplement unit 110 is connected to the main feed pipe 101 so as to supply air according to the amount of recycle gas that passes through the main feed pipe 101.
<9i> The air supplement unit 110 is installed between the main feed pipe 101 and an air inlet pipe 111 so as. to receive air from an exterior when the amount of recycle gas is insufficient. The air feed adjustment damper 115c is installed in the air inlet pipe 111.
<93> That is, the amount of recycle gas that passes through the main feed pipe 101 is detected by means of a gas detecting sensor 131 and a recycle gas state detecting device 151, which will be described later, and the detected data are transmitted to the central control panel 150, so that the central control panel 150 adjusts the operation of the air feed adjustment damper 115c based on the detected data in such a manner that a predetermined amount of air required for the combustion process can be fed into the combustion chambers 11 and 12.
<95> If the amount of the recycle gas that passes through the main feed pipe 101 is too excessive, the air feed adjustment damper 115c is closed, so that air being introduced into the combustion chambers 11 and 12 is shielded. <97> In this manner, if the amount of recycle gas that circulates through the main feed pipe 101 gradually increases, the amount of air fed into the air inlet pipe 111 is gradually reduced. In contrast, if the amount of recycle gas that circulates through the main feed pipe 101 gradually decreases, the amount of air fed into the air inlet pipe 111 is gradually increased.
<99> In addition, the combustion process must be carried out by feeding oxygen into gas in order to use the recycle gas for the purpose of waste combustion. To this end, the oxygen feed unit 120 is communicated with the feed pipes 101a to 101d so as to feed high-purity oxygen to the recycle gas selectively mixed with air.
<ioi> The oxygen feed unit 120 includes an oxygen reservoir tank 122 and an oxygen generator 123 connected to the oxygen generator 123 in order to feed oxygen into the oxygen reservoir tank 122. In order to feed oxygen having purity above 90% (preferably, above 95%) to the recycle gas selectively mixed with air, the oxygen reservoir tank 122 is communicated with a dry zone oxygen feed pipe 121a, the combustion zone oxygen feed pipe 121b, an after- combustion zone oxygen feed pipe 121c, and a second combustion chamber oxygen feed pipe 121d, which are connected to the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, and the second combustion chamber gas feed pipe 101d, respectively.
<i03> Further, in order to precisely adjust the flow rate of oxygen that passes through the oxygen feed pipes 121a to 121d, a dry zone oxygen feed control valve 124a, a combustion zone oxygen feed control valve 124b, an after-combustion zone oxygen feed control valve 124c, and a second combustion chamber oxygen feed control valve 124d are installed in the oxygen feed pipes 121a to 12Id, respectively.
<iO5> Therefore, high-purity oxygen is fed from the oxygen generator 123 and the oxygen reservoir 122 to a dry zone mixing chamber 21a, a combustion zone mixing chamber 21b, and an after-combustion zone mixing chamber 21c of a combustion unit 20 and the second combustion chamber gas feed pipe 101d through the oxygen feed pipes 121a to 121d and the oxygen feed control valves 124a to 124d. The recycle gas is mixed with the high-purity oxygen in the mixing chambers 21a to 21c in such a manner that the recycle gas has an oxygen rate of 21% or more (the oxygen rate may increase depending on combustion conditions) when the recycle gas is fed into the first and second combustion chambers 11 and 12.
<iO7> At this time, if the oxygen rate is increased by 5% to 6% from 21% when the recycle gas is fed into the first and second combustion chambers 11 and 12, high-temperature combustion can be realized with a low-air ratio.
<iO9> In the meantime, the incinerator 10 includes the first combustion chamber 11 used for burning waste and the second combustion chamber 12 installed above the first combustion chamber 11 so as to burn gas generated after the waste combustion process.
<iπ> The first and second combustion chambers 11 and 12 receive the recycle gas containing at least 21% of oxygen from the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, the after-combustion zone mixing chamber 21c, and the second combustion chamber gas feed pipe 101d so as to use the recycle gas for the combustion process.
<ii3> In addition, the combustion unit 20 is installed on the bottom of the first combustion chamber 11 such that the combustion unit 20 can be connected to the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, the dry zone oxygen feed pipe 121a, the combustion zone oxygen feed pipe 121b, and the after-combustion zone oxygen feed pipe 121c, respectively. Thus, when the waste combustion process is performed by feeding the recycle gas mixed with pure oxygen into the first combustion chamber 11, waste is burned while being stirred and moved in the form of a wave pattern by means of the combustion unit 20.
<ii5> Preferably, the combustion unit 20 is installed on the bottom of the first combustion chamber 11 in the step structure (for example, a three-step combustion unit is shown in FIG. 1). The combustion unit 20 consists of a dry zone nozzle/grate 20a, a combustion zone nozzle/grate 20b, and an after- combustion zone nozzle/grate 20c, which are sequentially installed from the upper portion of the combustion unit 20.
<ii7> The dry zone nozzle/grate 20a, the combustion zone nozzle/grate 20b, and the after-combustion zone nozzle/grate 20c have the same structure. Such a combustion unit 20 includes the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, which are connected to the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, the after-combustion zone gas feed pipe 101c, the dry zone oxygen feed pipe 121a, the combustion zone oxygen feed pipe 121b, and the after-combustion zone oxygen feed pipe 121c in order to mix the recycle gas with high-purity oxygen; grates 23 spaced apart from the mixing chambers 21a to 21c by a predetermined distance and formed at inner portions thereof with pressure chambers 24 in which a plurality of nozzles 25 are installed at one side of each pressure chamber 24; and pressure adjustment valves 22 installed between the mixing chambers 21a to 21c and pressure chambers 24 so as to adjust pressure of gas introduced into each pressure chamber 24 such that the recycle gas mixed with high-purity oxygen can be sequentially injected in the form of a wave pattern into the mixing chambers 21a to 21c through the nozzles 25.
<ii9> Thus, as shown in FIG. 2, the combustion unit 20 sequentially supplies gas through the pressure chambers 24 and nozzles 25 in the order of a, b, c, d, e, f and g by adjusting the pressure adjustment valves 22 while varying the gas feeding speed in a range of 50m/sec to 150m/sec, thereby performing the combustion process while stirring and moving waste in the form of a wave pattern.
<i2i> In the meantime, if the waste contains water excessively, the desired calorific value (heating value) cannot be obtained even if the waste has a high caloric value.
<123> For this reason, the dryer 30 is installed at the upstream of the combustion chambers 11 and 12 formed in the incinerator 10 so as to rapidly dry the waste.
<125> The dryer 30 includes a gas feed pressure chamber 31 installed at the sidewall of the incinerator 10 and connected to the recycle gas feed pipe lOle so as to receive the recycle gas and a dry nozzle 32 coupled to one side of the gas feed pressure chamber 31 so as to spray the recycle gas toward the waste.
<127> That is, the waste containing water that has been input into the feed hopper 13 of the incinerator 10 is rapidly dried while passing through the dryer 30, and then is moved into the first combustion chamber 11 so that rapid combustion is induced. Thus, the caloric value is increased while realizing higher heat recovery during the combustion process.
<129> In addition, a plurality of sensors 130 are installed in a region where the recycle gas is mixed with air, that is, the sensors 130 are provided in a predetermined portion of the main feed pipe 101 coupled with the air inlet pipe 111 in order to detect the amount of recycle gas selectively mixed with air, the temperature, and the amount of oxygen contained in the recycle gas. The sensors 130 consist of a gas detecting sensor 131 for detecting an amount of gas, a temperature detecting sensor 132 and an oxygen detecting sensor 133 for detecting an amount of oxygen contained in the gas. The sensors 130 send data related to the flow of detected gas to the recycle gas state detecting device 151. The central control panel 150 receives data from the recycle gas state detecting device 151 and sends signals to corresponding devices of the incinerating apparatus 1 in order to control the devices.
<i3i> Each device of the incinerating apparatus 1 is provided with a temperature controller 156 for receiving data related to the temperature of the recycle gas used for the combustion process and the temperature of each device, a first combustion chamber infrared temperature sensor 140a installed in the first combustion chamber 11 of the incinerator 10, a second combustion chamber infrared temperature sensor 140b installed in the second combustion chamber 12 of the incinerator 10, a first temperature gauge 140c provided in the waste heat boiler 50, a second temperature gauge 14Od provided in the gas discharge pipe 5b of the waste heat boiler 50, a third temperature gauge 14Oe provided in the gas discharge pipe 5c of the reactor 60, and temperature gauges 14Of to 14Oh provided in the bag filter 70.
<133> The combustion temperature condition is input into the central control panel 150 so as to control the temperature of each device. In addition, temperature data of the infrared temperature sensors 140a and 140b and the temperature gauges 140c to 140h are transmitted to the central control panel 150, so that the controller controls the devices based on the temperature, thereby maintaining optimal combustion conditions.
<135> The first and second combustion chamber infrared sensors 140a and 140b, which are installed in the first and second combustion chambers 11 and 12, respectively, may serve as sensors of a combustion control system. The first and second combustion chamber infrared sensors 140a and 140b have a rapid response speed, so that they can instantly measure the combustion temperature, thereby realizing stable combustion, stabilizing the amount of water being evaporated, and improving the characteristics of the recycle gas.
<137> In addition, first and second auxiliary burners 11a and 12a are installed in the first and second combustion chambers 11 and 12, respectively, in order to assist the combustion process.
<139> An internal pressure adjustment device 135 is installed in the pipe 5a provided between the second combustion chamber 12 of the incinerator 10 and the waste heat boiler 50 in order to check and adjust pressure of the above system for the purpose of stable combustion.
<i4i> If the amount of recycle gas discharged from the bag filter 70 is greater than the amount of gas used for the combustion process, the excessive recycle gas must be discharged to the exterior after being purified. To this end, the catalyst deodorizer tower 80 branches from the pipe 5d at a start point of the main feed pipe 101 so as to purify the recycle gas, and the stack 90 is installed at one side of the catalyst deodorizer tower 80 while being connected to the catalyst deodorizer tower 80 through the pipe 5e in order to discharge the purified gas to the exterior.
<143> The catalyst deodorizer tower 80 includes an SCR (selective catalyst reduction) tower containing the catalyst including about 65 weight percent of T1O2, V2O5, WO3, etc. The catalyst consists of three layers. The first layer is used for removing NOx and the second and third layers are used for removing dioxin by dissolving dioxin into CO2, H2O, HCl, etc.
<i45> Therefore, the recycle gas discharged from the bag filter 70 is introduced into the main feed pipe 101 by means of the recycle gas feed adjustment damper 115a, the gas adjustment damper 115b, and the guide blower 102b such that the recycle gas can be used for the combustion process. In addition, the remaining recycle gas is introduced into the catalyst deodorizer tower 80 by means of a guide blower 85 and the adjustment dampers 115k and 1151, which are installed in pipes 5d and 5e connected to the catalyst deodorizer tower 80 and the stack 90, respectively, and the remaining recycle gas is discharged to the exterior through the stack 90 after being purified by the catalyst deodorizer tower 80.
<147> If all of the recycle gas is circulated into the first and second combustion chambers 11 and 12, the adjustment dampers 115k and 1151 installed in the pipes 5d and 5e are closed and the operation of the catalyst deodorizer tower 80 is stopped.
<149> In this manner, if it is necessary to use great amount of gas for the waste combustion process, all of the recycle gas is circulated without being discharged to the exterior.
<i5i> FIG. 4 is a view illustrating the structure of the central control panel 150 for controlling the incinerating apparatus according to the present invention. The following description will be focused on the important parts of the central control panel 150.
<i53> The central control panel 150 receives data from the recycle gas state detecting device 151, an oxygen controller control unit 152, a gas controller 153, a damper controller 154, a package device controller 155, and the temperature controller 156 so as to control the above devices by transmitting signals to the devices.
<i55> The recycle gas state detecting device 151 detects the amount of gas, the temperature and the amount of oxygen contained in the gas from the gas detecting sensor 131, the temperature detecting sensor 132, and the oxygen detecting sensor 133, and then sends data thereof to the central control panel 150.
<157> ' The oxygen controller control unit 152 receives data related to the amount of oxygen from the oxygen detecting sensor 133. In this state, if oxygen generated from the oxygen generator 123 is fed into the oxygen reservoir tank 122, the oxygen controller control unit 152 controls the dry zone oxygen feed control valve 124a, the combustion zone oxygen feed control valve 124b, the after-combustion zone oxygen feed control valve 124c, and the second combustion chamber oxygen feed control valve 124d in such a manner that a predetermined amount of oxygen that has been preset in the controller can be fed into the gas feed pressure chamber 31 of the dryer 30, the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c.
<i59> The gas controller 153 controls the pressure adjustment valve 22 with a predetermined value that has been preset in the central control panel 150, when the recycle gas and oxygen, which have been mixed in the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, are fed into the dry zone nozzle/grate 20a, the combustion zone nozzle/grate 20b, and the after-combustion zone nozzle/grate 20c in such a manner that the recycle gas and oxygen can be fed at the gas feeding speed in a range of 50m/sec to 150m/sec, so that the combustion process can be performed while stirring and moving waste in the form of a wave pattern.
<i6i> The damper controller 154 controls the adjustment dampers 115a to 1151 based on program signals, which have been present in the central control panel 150 that receives data related to the gas flow from the gas detecting sensor 131, the temperature detecting sensor 132, and the oxygen detecting sensor 133.
<163> The package device controller 155 controls a hydraulic device, an air compressor, a truck scale, a waste crane, a waste crusher, a gas discharge inspection device, a deodorizer tower, etc.
<165> The temperature controller 156 receives data related to the temperature of the recycle gas and devices from the infrared temperature sensors 140a and 140b and the temperature gauges 140c to 14Oh, and then sends the temperature data to the central control panel 150 such that the combustion process can be performed with optimal combustion conditions.
<i67> Hereinafter, the operation of the incinerating apparatus 1 according to the present invention will be described.
<169> First, the first gas feed blower 102a and adjustment dampers 115f to 115j are driven before waste is input into the first and second combustion chambers 11 and 12 in order to rise the internal temperature of the first and second combustion chambers 11 and 12 to a level of 600°C or above. At the same time, the air adjustment damper 115c of the air inlet pipe 111 is opened so as to inject air into the first and second combustion chambers 11 and 12. After that, auxiliary burners 11a and 12a of the first and second combustion chambers 11 and 12 are operated, so that the internal temperature of the first and second combustion chambers 11 and 12 rise. In this state, waste is input into the hopper 13.
<i7i> The waste that has been input into the hopper 13 is moved in the form of a wave pattern while continuously passing through the dry zone nozzle/grate 20a, the combustion zone nozzle/grate 20b, and the after- combustion zone nozzle/grate 20c, so that the waste is incinerated or burned. . Thus, ash is discharged through the ash discharge port 14.
<173> The temperature of recycle gas discharged through the outlet port 15 of the incinerator 10 is about 1200°C or above. Such a high-temperature recycle gas is moved into the waste boiler 50 and the waste boiler 50 uses the recycle gas as a heat source in order to generate steam. The steam is transferred to the steam tank 51, so that a turbine generator 52 is operated, thereby producing electricity and energy to be used.
<i75> The recycle gas discharged through the waste boiler 50 has a temperature of about 230°C, and is moved into the semi-dry type alkali absorption reactor 60. The temperature of the recycle gas is reduced from 230 °C to 200°C at the semi-dry type alkali absorption reactor 60 and harmful gas contained in the recycle gas is removed. After that, the recycle gas is transferred to the bag filter 70.
<177> Here, if all of the recycle gas is circulated into the first and second combustion chambers 11 and 12, the semi-dry type alkali absorption reactor 60 does not use a medicine, but only uses water to move the recycle gas to the bag filter 70 by reducing the temperature of the recycle gas. The semi-dry type alkali absorption reactor 60 uses the medicine together with water to remove the harmful gas from the recycle gas only when it is necessary to discharge the remaining recycle gas to the atmosphere. Thus, the amount of medicines can be reduced in use.
<i79> In addition, the recycle gas that has been moved into the bag filter 70 passes through the filter 71 provided in the bag filter 70, so that dust and harmful materials contained in the recycle gas are removed.
<i8i> After that, a predetermined amount of the recycle gas discharged from the bag filter 70, which is required for the combustion process, is circulated into the first and second combustion chambers 11 and 12 of the incinerator 10 through the gas feed blowers 102a to 102c, adjustment dampers 115a to 115j , main feed pipes 101, and branch pipes 101a to 101e. In addition, the remaining recycle gas is transferred to the catalyst deodorizer tower 80 by means of the adjustment dampers 115k and 1151 and the guide blower 85. Thus, the remaining recycle gas is purified so that clean gas is discharged through the stack 90.
<i83> Hereinafter, the procedure for circulating the recycle gas, which has been discharged from the bag filter 70, for the combustion process and the procedure for mixing oxygen with the recycle gas will be described.
<i85> First, when all of the recycle gas is recycled, the operation of the catalyst deodorizer tower 80 and the guide blower 85 is stopped and the adjustment dampers 115k and 1151 are shut off.
<187> In addition, the recycle gas that has been discharged from the bag filter 70 is introduced into the main gas feed pipe 101 through the recycle gas feed adjustment damper 115a, the guide blower 102b, and the gas adjustment damper 115b.
<189> Here, when the recycle gas is introduced into the main feed pipe 101 from the bag filter 70 for the purpose of the combustion process, the damper controller 154 controls the recycle gas adjustment damper 115a such that a predetermined amount of recycle gas can be fed into the main feed pipe 101.
<i9i> If it is necessary to use the great amount of gas for the combustion process, all of the gas is recycled without being discharged to the exterior.
<i93> After that, the first gas feed blower 102a and the first combustion chamber gas feed adjustment damper 115j are operated, so that the recycle gas introduced into the main feed pipe 101 is fed into the dry zone gas feed pipe 101a, the combustion zone gas feed pipe 101b, and the after-combustion zone gas feed pipe 101c.
<i95> Then, the dry zone gas adjustment damper 115f, the combustion zone gas adjustment damper 115g, and the after combustion zone gas adjustment damper 115h are operated so that the recycle gas that has been fed into the gas feed pipes 101a to 101c is introduced into the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, respectively.
<i97> At this time, the gas detecting sensor 131, the temperature detecting sensor 132, and the oxygen detecting sensor 133 detect the amount of recycle gas, the temperature, and the amount of oxygen contained in gas, respectively, and then send the data related to the state of the gas flow to the recycle gas state detecting device 151. Accordingly, the central control panel 150 sends signals to each device based on the data received in the recycle gas state detecting device 151, thereby controlling the devices in such a manner that gas suitable for the combustion process can be obtained by mixing the recycle gas with oxygen.
<i99> The amount of recycle gas is detected by the gas detecting sensor 131 and the air adjustment damper 115c is controlled based on the amount of recycle gas detected by the gas detecting sensor 131 in such a manner that air can be mixed with the recycle gas if the amount of recycle gas is insufficient for the combustion process.
<20i> In the meantime, in order to reuse the recycle gas that has been fed into the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, oxygen must be mixed with the recycle gas. That is, not only is air containing 21% of oxygen added to the recycle gas, but also air having an increased oxygen enrichment rate above 21% must be provided to the recycle gas so as to obtain high- temperature combustion at a low air ratio.
<203> In this regard, the oxygen detecting sensor 133 detects the amount of oxygen contained in the recycle gas and then sends data to the oxygen controller control unit 152. When the oxygen is fed into the oxygen reservoir tank 122 from the oxygen, generator 123, the oxygen controller control unit 152 controls the dry zone oxygen feed control valve 124a, the combustion zone oxygen feed control valve 124b, and the after-combustion zone oxygen feed control valve 124c according to the amount of oxygen contained in the recycle gas, thereby feeding a predetermined amount of oxygen to the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c, respectively. Thus, the oxygen is mixed with the recycle gas, which has been fed into the mixing chambers 21a to 21c, during the combustion process.
<205> The recycle gas that has been fed into the dry zone mixing chamber 21a, the combustion zone mixing chamber 21b, and the after-combustion zone mixing chamber 21c is mixed with high-purity oxygen such that the recycle gas can contain 21% or more of oxygen, in which the oxygen rate may vary depending on the combustion condition. Thus, the recycle gas mixed with the oxygen is fed into the dry zone nozzle/grate 20a, the combustion zone nozzle/grate 20b, and the after-combustion zone nozzle/grate 20c. At this time, the pressure adjustment valve 22 is controlled according to data, which are preset in the central control panel 150, in such a manner that the recycle gas can be fed in the form of a wave pattern with a predetermined pressure. Therefore, waste can be stirred and burned while being moved in the form of the wave pattern.
<207> Thus, as shown in FIG. 2, the combustion unit 20 sequentially supplies the recycle gas in the order of a, b, c, d, e, f and g while varying the gas feeding speed in a range of 50m/sec to 150m/sec, thereby performing the combustion process while sequentially stirring and moving waste in the form of a wave pattern.
<209> Meanwhile, the second combustion chamber oxygen feed control valve 124d feeds high-purity oxygen to the second chamber 12 in accordance with the amount of recycle gas fed into the second combustion chamber 12.
<2ii> In addition, the dryer 30 installed at the downstream side of the hopper 13 receives the recycle gas from the recycle gas feed pipe lOle and the recycle gas feed adjustment damper 115i in order to dry waste by applying high-temperature gas to the waste. Thus, water contained in the waste is removed, thereby improving the calorific value of waste and raising the heat recovery efficiency.
<2i3> FIG. 5 is a block diagram illustrating the procedure for incinerating waste according to one embodiment of the present invention. In the following description, the structure and operation of the incinerator that have been already described above will be omitted in order to avoid redundancy. <2i5> As shown in FIG. 5, the procedure for incinerating waste according to one embodiment of the present invention mainly includes an incineration process 201, a steam production process 202, a harmful gas removal process 203, a harmful material removal process 204, a recycle process 205, an air supplement process 206, and an oxygen feed process 206a.
<217>
<2i8> A. Incineration Process
<2i9> The incineration process 201 refers to a process for burning waste by inputting the waste into the first and second combustion chambers 11 and 12 of the incinerator 10. That is, the waste that has been input into the first and second combustion chambers 11 and 12 through the hopper 13 of the incinerator 10 is burned in the first and second combustion chambers 11 and 12. Waste ash that has been produced after the incineration process is discharged to the exterior through the ash discharge port 14, and the recycle gas that has been generated during the incineration process is discharged through the outlet port 15 for the next steam production process 202.
<22i> The incineration process is divided into a first incineration process 201b performed in the first combustion chamber 11 of the incinerator 10, and a second incineration process 201c performed in the second combustion chamber 12 with respect to gas generated during the first incineration process 201b. The recycle gas mixed with high-purity oxygen is used during the first and second incineration processes 201b and 201c.
<223> In addition, when the first incineration process 201b is performed by using the recycle gas mixed with high-purity oxygen, gas is fed into the first combustion chamber 11 through nozzles 25 while varying the gas feeding speed in a range of 50m/sec to 150m/sec, in such a manner that the recycle gas can be fed in the form of the wave pattern through the nozzles 25, thereby stirring and moving waste in the form of a wave pattern during the first incineration process.
<225> In addition, a drying process 201a is performed before the waste is input into the first and second combustion chambers 11 and 12 of the incinerator 10 so as to dry the waste by using the recycle gas having the high temperature.
<227> The drying process 201a is performed prior to the first incineration process 201b so as to dry the waste by applying the recycle gas to the waste being inputted into the first combustion chamber 11 through the hopper 13. Since the waste is dried, the incineration process can be performed at a high speed so that the calorific value of waste and the heat recovery efficiency can be improved.
<229>
<230> B. Steam Production Process
<23i> The steam production process 202 refers to a process for producing steam to generate energy by feeding the high-temperature recycle gas that has been generated through the incineration process 201 into the waste boiler 50.
<233> That is, the high-temperature recycle gas that has been discharged from the incinerator 10 is fed into the waste boiler 50 so that the waste boiler 50 produces steam by using the high-temperature recycle gas. This steam is fed into the steam tank 51, thereby driving the turbine generator 52 to produce electricity. In this manner, the steam generated from the waste boiler 50 is transferred to various places to generate energy, such as electricity.
<235>
<236> C. Temperature Reduction and Harmful Gas Removal Process <237> The temperature reduction and harmful gas removal process 203 refers to a process for reducing the temperature of the recycle gas and removing harmful gas from the recycle gas by feeding the recycle gas into the semi-dry type alkali absorption reactor 60 after the steam production process 202. <239> The recycle gas has the temperature of about 230°C when the recycle gas is discharged from the waste boiler 50. The temperature of the recycle gas is reduced to about 200°C in the reactor 60. Accordingly, it is possible to protect the bag filter 70 from the high temperature during the next harmful material removal process 204. <24i> In addition, as described above, if the recycle gas is fed into the semi-dry type alkali absorption reactor 60, hydrogen chloride (HCl) and sulfur oxide (SOx) may react with slacked lime slurry, thereby converting harmful acid gas contained in the recycle gas into harmless neutralized salt.
<243> Meanwhile, if all of the recycle gas is circulated into the first and second combustion chambers 11 and 12, the semi-dry type alkali absorption reactor 60 does not use a medicine, but only uses water to move the recycle gas to the bag filter 70 by reducing the temperature of the recycle gas. The semi-dry type alkali absorption reactor 60 uses the medicine together with water to remove the harmful gas from the recycle gas only when it is necessary to discharge the remaining recycle gas to the atmosphere. Thus, the amount of medicines can be reduced in use.
<245>
<246> D. Harmful Material Removal Process
<247> The harmful material removal process 204 refers to a process for removing harmful materials from the recycle gas by feeding the recycle gas into the bag filter 70 after the temperature reduction and harmful gas removal process 203.
<249> That is, the recycle gas discharged from the semi-dry type alkali absorption reactor 60 is fed into the bag filter 70 such that dust and harmful materials contained in the recycle gas can be filtered while the recycle gas is passing through the filter 71 of the bag filter 70.
<251>
<252> E. Recycle Process
<253> The recycle process 205 refers to a process for circulating the recycle gas into the first and second combustion chambers 11 and 12 of the incinerator 10 after the harmful material removal process 204.
<255> That is, in a state that the outlet of the bag filter 70 is connected to the first and second combustion chambers 11 and 12 through the main feed pipe 101 and branch pipes 101a to lOle, the blower 102 and adjustment dampers 115a to 115j are installed in the main feed pipe 101 and branch pipes 101a to lOle, so that the recycle gas discharged from the bag filter 70 is circulated into the first and second combustion chambers 11 and 12 of the incinerator 10 to burn the waste.
<257>
<258> F. Air Supplement Process
<259> The air supplement process 206 refers to a process for selectively supplying air to the recycle gas during the recycle process 205 in order to burn the waste.
<26i> That is, if the amount of recycle gas fed into the main feed pipe 101 exceeds a predetermined reference level, the air adjustment damper 115c of the air inlet pipe 111 is shut off, thereby stopping air supply. In contrast, if the amount of recycle gas fed into the main feed pipe 101 is less than a predetermined reference level, the air adjustment damper 115c of the air inlet pipe 111 is opened so that air can be fed through the main feed pipe 101 in such a manner that the air can be mixed with the recycle gas.
<263>
<264> G. Oxygen Feed Process
<265> The oxygen feed process 206a refers to a process for supplying oxygen having purity of 90% or more (preferably, 95% or more) to the recycle gas, which has been mixed with air through the air supplement process 206, during the recycle process 205.
<267> That is, a sensor 130 is installed in the main feed pipe 101 at a position where the recycle gas is mixed with air, thereby detecting the amount of oxygen contained in the recycle gas. If it is detected that the amount of oxygen in the recycle gas is insufficient, a predetermined amount of oxygen is fed into the recycle gas for the purpose of combustion.
<269> At this time, it is preferred for the recycle gas to have the oxygen rate of about 21% or more. If the oxygen rate is further increased by 5% to 6% from 21%, high-temperature combustion can be realized with a low-air ratio.
<27i> Meanwhile, if it is necessary to use the great amount of recycle gas for the waste combustion process, all of the recycle gas is circulated without being discharged to the exterior. However, if the amount of recycle gas is greater than the amount of gas required for the combustion process during the recycle process 205, a recycle gas purification process 207 and a discharge process 208 are further performed so as to discharge the extra recycle gas after purifying the recycle gas.
<273> Therefore, in usual, all of the recycle gas is circulated into the first and second combustion chambers 11 and 12 of the incinerator 10 through the recycle process 205, the air supplement process 206 and the oxygen feed process 206a so that the exhaust gas is not discharged to the exterior. Thus, it is not necessary to perform the recycle gas purification process 207 and the discharge process 208.
<275> In addition, if the amount of recycle gas is greater than the amount of gas required for the combustion process, the extra recycle gas is purified and discharged to the exterior through the recycle gas purification process 207 and the discharge process 208. Thus, the amount of gas discharged to the exterior can be significantly reduced.
<277> Table 1 shows data representing the difference between the conventional incinerating apparatus and the incinerating apparatus according to the present invention.
<279>
<280> Table 1
<281>
Figure imgf000028_0001
<282> (Reference: David Gordon Wilson, "HANDBOOK OF SOLID WASTE MANAGEMENT (1997)" P37-38).
<284> <285> Table 1 is obtained from various waste materials shown in Table 2 by mixing high-purity oxygen with the recycle gas on the basis of following conditions^
<287> 1. Amount of incinerated waste: 4,167kg/hr <288> 2. Operation time: 24hr/day <289> 3. Amount of incineration per day: 100,OOOkg/day <290> 4. Water content: <291>
<293> Table 2
Figure imgf000029_0001
<295>
<296> I. Calculation for Element Composition <297> <298> 1. Calculation of heating value: Dulong Type <299> Hwo = 8,100[C] + 34,000 [H-(0/8)] + 2,500[S]kcal/kg
<300> = 8,100 x 0.7290 + 34,000[0.1087-(0.1472?)] +2,50Ox 0.00035 <301> = 8,977kcal/kg (dry-based higher heating value) <302> <303> 2. Calculation of lower heating value: wet-based lower heating valued!^)
<305> Hwo x inflammable - 600 [9H + W]
<306> = 8,977 x 0.6593 - 600 x (9 x 0.0717 + 0.3000) <307> = 5,351kcal/kg <3O8> <309> 3. Calculation of exhaust gas: water-containing mixed waste <310> 1) Theoret i cal air amount (Awo) <311> Are = 8.89[C] + 26.7 [H-0/8] + 3.33[S] Nm'/kg
<312> = 0.89 x 0.4807 + 26.7 x [0.0717-(0.0970 ?8) ] + 3.33 x 0.0002 <313> = 5.86 NmVkg <314> 2) Real ai r amount (A) <315> A = mAivo (excessive ai r rate : 1.7)
<316> = 1.7 x 5.86 <317> = 9.96 Nm1 /kg <318> -real air amount (A' ) during incineration process: 4.167kg/hr <319> A' = 4.167kg/hr x 9.96 Nm1/kg <320> = 41,500 NmVhr (amount of air used for the combustion process according to the present invention.)
<322> 3) Real amount of wet combustion gas (Gw)
Gas type ' Composition Amount of Mass of CONl 'ENTS (%) gas Nm" /leg , gas kg/kg Nm3 : κg_
CO2 : 1.867 [C] 0.897378 : 1.7627 8.533 ' 13.101
SO2 I 0.7TSl 0.000162 I 0.0005 0.002 ! 0.004
H3O i 11.2[H]H-1.244[Wl L 17607 1 0,9451 11.183 7.024
N2 JjV74mAwo+G-8lNj 737214 _! 9.2152 70.079 68.49
O2 3 *0.2ό(m-1 )Awo 1.665 |_ 1.5236 10.141 i 11.324
HCl I 0,63CI 0.00474 J_0.0077 0.045 I 0.057
Gw i \ 10.517014 I 13.4548 100 I 100.001
<323> <324> (mass of gas (kg/kg) = gas amount [Nm /kg] x molecular weight
[kg/kmol]/22.4[Nm3/kg]
<326> * is an oxygen enrichment rate in gas.
<327> <328> 4) Real amount of dry combustion gas (Gd)
<329> Gd = (m-0.27) Aw + 1.867[C] + 0.7[S] + 0.73[N]
<330> - (1.7 - 0.21) x 5.86 +1.867 x 0.4870 +0.7x 0.0002 + 0.8 x 0.0022
<331> = 9.63 NmVkg <332> 5) Real amount of wet discharge gas (fe)
<333> Giv2 = GiV1 x amount of incineration kg/hr)
<334> = 10.52 x 4,167
<335> = 43.833 NmVhr
<336> 6) Real amount of dry discharge gas (Gdi)
<337> Gdi - Gd x amount of incineration kg/hr)
<338> = 9.63 x 4,167
<339> = 40,125 Nm3 /hr (amount of gas used in the present invention)
<340> 7) Amount of steam (W8)
Figure imgf000031_0001
<342> = 43,833 - 40,125
<343> = 3,708 NmVhr
<344>
<345> II. Heat balance in the incinerator of the present invention
<346>
<347> 1. Design Conditions
<348> (T) Amount of incinerated waste [WR]: 4,167 kg/hr
<349> (2) Real amount of wet discharge gas [Gff2] : 43,833 NmVhr
<350> ® Average temperature of waste [TJ : 20°C
<35i> ® Specific heat of air at constant volume [CP3]: 0.310 kcal/Nm3°C
<352> © Temperature of recycle gas [T3]: 170°C
<353> © Specific heat of waste [CPf]: 0.475 kcal/NπTC
<354>
<355> 2. Heat input
<356> φ Sensible heat of waste QH)
<357> QH = WR X CPf x Tw [kcal/hr]
<358> = 4,167 x 0.475 x 20 <359> = 39,583 kcal/hr
<360> (2) Combustion heat value of waste QR)
<36i> QR = WR X H1VL [kcal/hr]
<362> = 4,167 x 5,351
<363> - 22,297,281 kcal/hr
<364> (H) Heat value of air fed into furnace (QA)
<365> QA = A' x Cpa x Ta[kcal/hr] (A' is an amount of air fed into the furnace: 41,500Nm7hr)
<367> = 41,500.x 0.310 x 170
<368> = 2,187,047 kal/hr
<369> ® Total heat input
Figure imgf000032_0001
QA
<37i> = 39,583 + 22,297,281 = 2,187,047
<372> - 24,523,911 kcal/hr
<373>
<374> 3. Heat Output (Q0P)
<375> φ Heat value of discharged recycle gas (QCT)
<376> QCT = Gw2 x Cpg x Tg [kcal/hr]
<377> = 43,833 CpgTg
<378> φ Heat of ignition for waste (Qwi)
<379> QW1 = fR X CP X T [kcal/hr]
<380> = 4,167 x 0.3 x 200
<38i> = 250,000 kcal/hr
<382> (2) Heal loss (Qff2) in second chamber caused by radiation and conduction
<383> QW22 - 15% of heat input
<384> = 3,678,587 kcal/m'hr
<385> Qff22 = 3,678,587 kcal/hr <386> @ Heat loss of ash (Q1.) : Heat loss caused by unburned carbon powder remaining in ash and sensible heat of ash.
<388> Q1. = 8,100 x α (n /(1-n)) x WR + WA x RA x tA
<389> = (α/(l-n)) x WR x ( 8,100 x n + RA x tA )
<390> & : powder contained in waste (lkg) = 0.0582 [kg/kg]
<39i> n: unburned carbon in ash (lkg) = 0.03 [kg/kg]
<392> WR: amount of incinerated waste = 1,467 [kg/hr]
<393> WA: amount of ash, WA = («/(l-n)) x WR
<394> ' rA: specific heat of ash (kcal/kg°C) '= 0.25 [kcal/kg°C]
<395> tA: temperature of ash CO = 500 °C
<396> Qr = 92,000 kal/hr
<397> © Total heat output
<398> QOP = QCT + Q,i + QW2 + Qr
<399> = 43,833 CpgTg + 250,000 + 3,678,587 + 92,000
<4oo> = 43,833 CpgTg + 4,020,586
<401>
<402> 4. Temperature of recycle gas at the outlet
<403> Heat input = Heat output
<404> 24,523,911 = 48,833 CPgTg + 4,20,586
<405> CpgTg = 467,76
<406> - Trial and Error
<407> At the temperature of 1,0000C,
Figure imgf000033_0001
<409> At the temperature of l,100°C,
Figure imgf000033_0002
<4ii> = (401.94 - 361.30)/(l,100 - 1,000)
<4i2> = 0.406. <413> Thus, (467.76 - 361.30)/0.406 = 262°C <414> Temperature of recycle gas = 1,000 + 262 = 1,262°C <415> (D Average specific heat of main gases at constant volume Cp8 (kcal/Nm3 °C)
422.97
Figure imgf000034_0001
<418> (2) Specific heat of combustion gas at l,262°C(Cpgi)
Figure imgf000034_0002
= α262-l,000)x(0.366-0.361) + 0361 =0372 m (1,100-1,000)
<421> <422> -Amount of gas used for combustion process (real amount of gas): 41,500 Nm'/hr
<424> -Amount of recycle gas used in the present invention (real amount of dry discharge gas): 40,125 NmVhr
<426> -Air supplement: 41,500 - 40,125 = 1,375 Nm3/hr
<427>

Claims

[CLAIMS] [Claim 1]
A method for incinerating waste by circulating exhaust gas in an incinerator, the method comprising: an incineration process 201 for burning waste by inputting the waste into first and second combustion chambers 11 and 12 of an incinerator 10; a steam production process 202 for producing steam to generate energy by feeding high-temperature recycle gas that has been generated through the incineration process 201 into a waste boiler 50; a temperature reduction and harmful gas removal process 203 for reducing a temperature of the recycle gas and removing harmful gas from the recycle gas by feeding the recycle gas into a semi-dry type alkali absorption reactor 60 after the steam production process 202; a harmful material removal process 204 for removing harmful materials from the recycle gas by feeding the recycle gas into a bag filter 70 after the temperature reduction and harmful gas removal process 203; a recycle process 205 for circulating the recycle gas into the first and second combustion chambers 11 and 12 of the incinerator 10 after the harmful material removal process 204; and an air supplement process 206 for selectively supplying air to the recycle gas based on an amount of the recycle gas during the recycle process 205 in order to burn the waste.
[Claim 2]
The method as claimed in claim 1, wherein, if the amount of recycle gas is insufficient during the air supplement process 206, air is fed into a main feed pipe 101 through which the recycle gas flows.
[Claim 3]
The method as claimed in claim 1, further comprising an oxygen feed process 206a for feeding oxygen having purity of 90% or more to the recycle gas, which is selectively mixed with air in the air supplement process 206, during the recycle process 205.
[Claim 4]
The method as claimed in claim 3, wherein a sensor 130 is installed in a predetermined region of the main feed pipe 101, where the recycle gas is mixed with air, in order to detect an amount of oxygen contained in the recycle gas selectively mixed with air, and a predetermined amount of oxygen is fed into the recycle gas when it is detected by the sensor 130 that oxygen in the recycle gas is insufficient.
[Claim 5]
The method as claimed in claim 1, wherein the incineration process 201 includes a first incineration process 201b for burning the waste and a second incineration process 201c for burning gas generated during the first incineration process 201b, in which the first and second incineration processes 201b and 201c are performed by using the recycle gas mixed with oxygen.
[Claim 6]
The method as claimed in claim 5, wherein, when the first incineration process 201b is performed by using the recycle gas mixed with high-purity oxygen, gas is fed into the first combustion chamber 11 through a plurality of nozzles 25 while varying gas pressure, in such a manner that the recycle gas is fed in a form of a wave pattern, thereby stirring and moving waste in a form of a wave pattern during the first incineration process 201b.
[Claim 7]
The method as claimed in claim 1, further comprising a drying process 201a for drying the waste by using the recycle gas before the waste is input into the first and second combustion chambers 11 and 12 of the incinerator.
[Claim 8]
The method as claimed in claim 1, wherein, if an amount of the recycle gas is greater than an amount of gas required for a combustion process during the recycle process 205, a recycle gas purification process 207 and a discharge process 208 are further performed in order to discharge extra recycle gas to an exterior after purifying the extra recycle gas.
[Claim 9]
An incinerating apparatus for incinerating waste by circulating gas such that the gas is mixed with oxygen, the apparatus comprising: an incinerator 10 provided at an upper end portion thereof with a hopper 13 for feeding the waste, formed at an inner portion thereof with first and second combustion chambers 11 and 12, and provided at a lower end portion thereof with an ash discharge port 14; a waste heat boiler 50 installed at one side of the incinerator 10 and connected to one side of the incinerator 10 through a pipe 5a in order to generate steam by using the recycle gas as a heat source; a reactor 60 installed at one side of the waste heat boiler 50 and connected to the waste heat boiler 50 through a pipe 5b in order to remove harmful gas contained in the recycle gas and to reduce a temperature of the recycle gas discharged from the waste heat boiler 50; a bag filter 70 installed at one side of the reactor 60 and connected to the reactor 60 through a pipe 5c, in which the bag filter 70 is provided at an inner portion thereof with a filter 71 so as to filter harmful materials contained in the recycle gas discharged from the reactor 60; a recycle unit 100 including a main feed pipe 101 and branch pipes 101a to 101d, which connect the bag filter 70 to the first and second combustion chambers 11 and 12 so as to circulate the recycle gas from the bag filter 70 to the first and second combustion chambers 11 and 12 of the incinerator 10, and a blower 102 installed above the main feed pipe 101 and branch pipes 101a to 101d in order to blow the recycle gas; and an air supplement unit 110 connected to the main feed pipe 101 so as to supply air according to the amount of the recycle gas that passes through the main feed pipe 101.
[Claim 10]
The apparatus as claimed in claim 9, wherein the air supplement unit 110 is connected to the main feed pipe 101 through an air inlet pipe 111 in order to feed external air into the main feed pipe 101 when the amount of recycle gas is insufficient.
[Claim 11]
The apparatus as claimed in claim 9 or 10, wherein an oxygen feed unit 120 is communicated with the branch pipes 101a to 101d so as to feed high- purity oxygen to the recycle gas selectively mixed with air.
[Claim 12]
The apparatus as claimed in claim 11, wherein an oxygen reservoir tank
122 communicated with oxygen feed pipes 121a to 121d is installed in the branch pipes 101a to 101d in order to feed oxygen having purity of 90% or more to the recycle gas selectively mixed with air, and an oxygen generator
123 is connected to the oxygen reservoir tank 122 so as to feed oxygen to the oxygen reservoir tank 122.
[Claim 13]
The apparatus as claimed in claim 12, wherein the first combustion chamber 11 is used for incinerating the waste and the second combustion chamber 12 is installed above the first combustion chamber 11 so as to burn gas generated from the first combustion chamber 11, in which the recycle gas mixed with oxygen is fed into the first and second combustion chambers 11 and 12, respectively, during the combustion process.
[Claim 14]
The apparatus as claimed in claim 13, wherein a combustion unit 20 is installed on a bottom of the first combustion chamber 11 and is connected to the branch pipes 101a to 101c and the oxygen feed pipes 121a to 121c in order to feed the recycle gas mixed with oxygen into the first combustion chamber 11, in such a manner that waste is burned while being stirred and moved in a form of a wave pattern by means of the combustion unit 20.
[Claim 15]
The apparatus as claimed in claim 14, wherein the combustion unit 20 includes mixing chambers 21a to 21c, which are connected to the branch pipes 101a to 101c and the oxygen feed pipes 121a to 121c in order to mix the recycle gas with oxygen; grates 23 spaced apart from the mixing chambers 21a to 21c by a predetermined distance and formed at inner portions thereof with pressure chambers 24 in which a plurality of nozzles 25 are installed at one side of each pressure chamber 24;and pressure adjustment valves 22 installed between the mixing chambers 21a to 21c and pressure chambers 24 so as to adjust pressure of gas introduced into each pressure chamber 24 such that the recycle gas mixed with oxygen is sequentially injected in a form of a wave pattern into the mixing chambers 21a to 21c through the nozzles 25. [Claim 16]
The apparatus as claimed in claim 15, wherein a plurality of combustion units 20 are installed on the bottom of the first combustion chamber 11 in a stepped pattern. [Claim 17]
The apparatus as claimed in claim 12, wherein a plurality of adjustment dampers 115a to 115j and oxygen feed control valves 124a to 124d are installed in the main feed pipe 101, branch pipes 101a to 101c, and oxygen feed pipes 121a to 121d so as to adjust a flow rate of gas passing therethrough. [Claim 18]
The apparatus as claimed in claim 9, wherein a dryer 30 is installed at an upstream of the combustion chambers 11 and 12 formed in the incinerator 10 so as to rapidly dry the waste, in which the dryer 30 includes a gas feed pressure chamber 31 installed at a sidewall of the incinerator 10 and connected to the recycle gas feed pipe lOle so as to receive the recycle gas and a dry nozzle 32 coupled to one side of the gas feed pressure chamber 31 so as to spray the recycle gas toward the waste. [Claim 19]
The apparatus as claimed in claim 17, wherein a sensor 130 is installed in a region where the recycle gas is mixed with air in order to detect an amount of recycle gas selectively mixed with air, a temperature, and an amount of oxygen contained in the recycle gas, and a central control panel 150 controls the adjustment dampers 115a to 115j and oxygen feed control valves 124a to 124d based data received from the sensor 130. [Claim 20]
The apparatus as claimed in claim 9, further comprising a catalyst deodorizer tower 80, which branches from a pipe 5d at a start point of the main feed pipe 101 so as to purify the recycle gas, and a stack 90 installed at one side of the catalyst deodorizer tower 80 and connected to the catalyst deodorizer tower 80 through a pipe 5e in order to discharge purified gas to the exterior, when the amount of the recycle gas that has passed through the bag filter 70 is greater than the amount of gas required for the combustion process.
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