WO2006118369A1 - Hybrid-type apparatus for treating exhaust gas having a condenser - Google Patents
Hybrid-type apparatus for treating exhaust gas having a condenser Download PDFInfo
- Publication number
- WO2006118369A1 WO2006118369A1 PCT/KR2005/003234 KR2005003234W WO2006118369A1 WO 2006118369 A1 WO2006118369 A1 WO 2006118369A1 KR 2005003234 W KR2005003234 W KR 2005003234W WO 2006118369 A1 WO2006118369 A1 WO 2006118369A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- exhaust gas
- powder
- bag filter
- chemical
- release agent
- Prior art date
Links
- 238000005200 wet scrubbing Methods 0.000 claims abstract description 72
- 239000000843 powder Substances 0.000 claims abstract description 70
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 62
- 239000000126 substance Substances 0.000 claims abstract description 62
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 45
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 45
- 239000004571 lime Substances 0.000 claims abstract description 45
- 238000005203 dry scrubbing Methods 0.000 claims abstract description 20
- 238000001816 cooling Methods 0.000 claims abstract description 12
- 238000005507 spraying Methods 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 38
- 238000000926 separation method Methods 0.000 claims description 37
- 239000000428 dust Substances 0.000 claims description 29
- 239000007921 spray Substances 0.000 claims description 27
- 239000010802 sludge Substances 0.000 claims description 26
- 239000007788 liquid Substances 0.000 claims description 25
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 9
- 238000009833 condensation Methods 0.000 claims description 9
- 230000005494 condensation Effects 0.000 claims description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 8
- 239000000919 ceramic Substances 0.000 claims description 7
- 230000005484 gravity Effects 0.000 claims description 5
- 239000003513 alkali Substances 0.000 claims description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 4
- 239000010451 perlite Substances 0.000 claims description 4
- 235000019362 perlite Nutrition 0.000 claims description 4
- 229910021536 Zeolite Inorganic materials 0.000 claims description 3
- 239000011230 binding agent Substances 0.000 claims description 3
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 3
- 239000002562 thickening agent Substances 0.000 claims description 3
- 239000010457 zeolite Substances 0.000 claims description 3
- 229920002472 Starch Polymers 0.000 claims description 2
- 239000000440 bentonite Substances 0.000 claims description 2
- 229910000278 bentonite Inorganic materials 0.000 claims description 2
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 2
- 238000001354 calcination Methods 0.000 claims description 2
- SHFGJEQAOUMGJM-UHFFFAOYSA-N dialuminum dipotassium disodium dioxosilane iron(3+) oxocalcium oxomagnesium oxygen(2-) Chemical compound [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Na+].[Na+].[Al+3].[Al+3].[K+].[K+].[Fe+3].[Fe+3].O=[Mg].O=[Ca].O=[Si]=O SHFGJEQAOUMGJM-UHFFFAOYSA-N 0.000 claims description 2
- 239000005332 obsidian Substances 0.000 claims description 2
- -1 pitchstone Substances 0.000 claims description 2
- 239000008262 pumice Substances 0.000 claims description 2
- 239000011435 rock Substances 0.000 claims description 2
- 239000000741 silica gel Substances 0.000 claims description 2
- 229910002027 silica gel Inorganic materials 0.000 claims description 2
- 239000008107 starch Substances 0.000 claims description 2
- 235000019698 starch Nutrition 0.000 claims description 2
- 239000010455 vermiculite Substances 0.000 claims description 2
- 229910052902 vermiculite Inorganic materials 0.000 claims description 2
- 235000019354 vermiculite Nutrition 0.000 claims description 2
- 238000005201 scrubbing Methods 0.000 abstract description 26
- 239000002253 acid Substances 0.000 abstract description 16
- 239000000383 hazardous chemical Substances 0.000 abstract description 15
- 239000000779 smoke Substances 0.000 abstract description 10
- 239000012855 volatile organic compound Substances 0.000 abstract description 9
- 231100001261 hazardous Toxicity 0.000 abstract description 8
- 238000009434 installation Methods 0.000 abstract description 8
- 238000001035 drying Methods 0.000 abstract description 6
- 239000010813 municipal solid waste Substances 0.000 abstract description 5
- 238000012423 maintenance Methods 0.000 abstract description 3
- 238000002485 combustion reaction Methods 0.000 abstract description 2
- 238000010276 construction Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 120
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 21
- 239000000243 solution Substances 0.000 description 20
- 238000006243 chemical reaction Methods 0.000 description 17
- 238000000034 method Methods 0.000 description 10
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 6
- KVGZZAHHUNAVKZ-UHFFFAOYSA-N 1,4-Dioxin Chemical compound O1C=COC=C1 KVGZZAHHUNAVKZ-UHFFFAOYSA-N 0.000 description 5
- 239000011575 calcium Substances 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 239000012670 alkaline solution Substances 0.000 description 4
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 4
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 3
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- 239000011780 sodium chloride Substances 0.000 description 3
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 229910002089 NOx Inorganic materials 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- CHWRSCGUEQEHOH-UHFFFAOYSA-N potassium oxide Chemical compound [O-2].[K+].[K+] CHWRSCGUEQEHOH-UHFFFAOYSA-N 0.000 description 2
- 229910001950 potassium oxide Inorganic materials 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 2
- 229910001948 sodium oxide Inorganic materials 0.000 description 2
- 229910052815 sulfur oxide Inorganic materials 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 239000000809 air pollutant Substances 0.000 description 1
- 231100001243 air pollutant Toxicity 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 238000007084 catalytic combustion reaction Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000012024 dehydrating agents Substances 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 239000002274 desiccant Substances 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000001473 noxious effect Effects 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000006552 photochemical reaction Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
- B24B7/06—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor involving conveyor belts, a sequence of travelling work-tables or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/81—Solid phase processes
- B01D53/83—Solid phase processes with moving reactants
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/002—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by condensation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/60—Simultaneously removing sulfur oxides and nitrogen oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/75—Multi-step processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B27/00—Other grinding machines or devices
- B24B27/0061—Other grinding machines or devices having several tools on a revolving tools box
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B47/00—Drives or gearings; Equipment therefor
- B24B47/10—Drives or gearings; Equipment therefor for rotating or reciprocating working-spindles carrying grinding wheels or workpieces
- B24B47/14—Drives or gearings; Equipment therefor for rotating or reciprocating working-spindles carrying grinding wheels or workpieces by liquid or gas pressure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
- B24B7/20—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground
- B24B7/22—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain
Definitions
- the present invention relates to an apparatus for treating exhaust gas exhausted from thermal installations such as a hazardous substance drying apparatus, a municipal solid waste incinerator and a furnace. More particularly, the present invention relates to a hybrid- type apparatus for treating exhaust gas, wherein an alkaline chemical solution is first sprayed to exhaust gas so as to neutralize the exhaust gas, the exhaust gas is secondly passed through a bag filter or a bag filter with a release agent layer and a chemical layer adhering thereto so as to remove residual hazardous substances of the exhaust gas, and the exhaust gas is thirdly passed through a condenser so as to remove white smoke and malodor.
- Exhaust gas generated from an incinerator for incinerating municipal solid wastes or industrial wastes contains hazardous substances such as dust, acid gases (HCl, SOx, NOx, HF, etc.), heavy metals (Hg, Cd, Pb, As, Zn, etc.), and dioxin. Furthermore, exhaust gas exhausted upon drying of food garbage or hazardous substances also contains a large amount of dust or noxious gases and malodorous fine dust. Particularly, exhaust gas generated upon drying of food garbage or hazardous substances contains volatile organic compounds (VOCs) that generate smog through photochemical reaction and are the cause of malodor.
- VOCs volatile organic compounds
- Conventional methods for treating such hazardous exhaust gas include a method in which an alkaline solution is sprayed to exhaust gas to remove dust therefrom or neutralize the exhaust gas in a wet process and the exhaust gas is incinerated in a de- odorization furnace, subsequently dehydrated to remove moisture therefrom and then exhausted, and a method in which a lime slurry is supplied to exhaust gas to neutralize the exhaust gas in a semi-dry process, the neutralized exhaust gas is passed through a bag filter to remove dust therefrom and then exhausted.
- additional equipment for burning the VOCs using a catalyst may be installed at the rear of a scrubber.
- Korean Patent Application No. 10-2004-0093768 filed in the name of the applicant and entitled Hybrid-type apparatus for treating exhaust gas discloses a method and apparatus for treating exhaust gas by wet-scrubbing acid exhaust gas containing dust and directly passing the wet-scrubbed exhaust gas through a bag filter (hereinafter, a method for treating exhaust gas by wet-scrubbing acid exhaust gas containing dust and directly passing the wet-scrubbed exhaust gas through a bag filter is referred to as a hybrid-type method for treating exhaust gas ). Furthermore, Korean Patent Application No.
- An object of the present invention is to provide a hybrid-type apparatus for treating exhaust gas, wherein various kinds of hazardous exhaust gas can be completely scrubbed and then exhausted to the atmosphere.
- an object of the prevent invention is to provide an apparatus for treating exhaust gas having a condenser, wherein VOCs or malodor can be removed and generation of white smoke can be prevented without installation of an additional catalytic combustion device.
- an object of the present invention is to provide a hybrid-type apparatus for treating exhaust gas, wherein releasing agent powder and chemical powder are supplied to a bag filter to completely remove hazardous substances of exhaust gas and the bag filter can be used semi-permanently, thereby improving economical efficiency due to low maintenance costs.
- a hybrid-type apparatus for treating exhaust gas comprises a wet scrubbing means including a wet scrubbing chamber that has an inlet through which exhaust gas is introduced, an outlet through which treated exhaust gas flows out, and a drain hole formed at a position in a side surface thereof spaced apart by a certain distance upwardly from the bottom thereof, and is disposed such that the exhaust gas introduced through the inlet horizontally flows toward the outlet, an eliminator that is disposed within the wet scrubbing chamber to divide the interior of the wet scrubbing chamber into an inlet-side space and an outlet-side space, has a plurality of bent blades arranged to form a passage for the exhaust gas, and is installed such that the bottom thereof is positioned below the drain hole, and a spray nozzle for spraying liquid into the inlet-side space of the wet scrubbing chamber; a dry scrubbing means including a duct having one end connected to the outlet of the wet scrubbing chamber, a bag filter connected to the
- the wet scrubbing means may further comprise an oil/water separation tank including a plurality of reservoirs to scrub liquid received from the drain hole by sequentially passing the liquid through the plurality of reservoirs; a concentrating tank for receiving sludge precipitated in the oil/water separation tank and concentrating the sludge therein; and a dehydrator for receiving the concentrated sludge from the concentrating tank, separating remaining liquid from the concentrated sludge, supplying the separated liquid to one of the reservoirs of the oil/water separation tank, and discharging a cake of sludge obtained through the separation of the remaining liquid.
- the spray nozzle may be installed to receive liquid from a final treatment reservoir of the reservoirs of the oil/water separation tank and to spray the liquid into the inlet-side space of the wet scrubbing chamber.
- the wet scrubbing means may be adapted to supply an alkaline chemical to the oil/water separation tank to scrub acid exhaust gas. That is, the wet scrubbing means may further comprise a pH sensor installed at the oil/water separation tank; an alkali chemical storage tank; a chemical feed pump connected to the storage tank to feed an alkali chemical to the oil/water separation tank; and a controller for receiving a value measured by the pH sensor and supplying the chemical to the oil/water separation tank by operating the chemical feed pump if the measured value is in a predetermined range.
- the bag filter includes a baffle installed between an inlet connected to the duct and the bag, and a rotary valve installed at a lower portion of the bag filter, the rotary valve includes a plurality of blades arranged at a predetermined interval along the circumference of the rotary valve, and the rotary valve is rotated at a predetermined speed to intermittently supply external air from the lower portion of the bag filter when the chemical spray means supplies the release agent powder and the chemical powder to the bag filter, so that the release agent powder and the chemical powder can uniformly adhere to the surface of the bag.
- the condenser preferably comprises a condensation chamber in which a plurality of cooling pipes are installed such that the exhaust gas supplied from the bag filter passes by the cooling pipes, and a second blower installed to suck external air and to cause the external air to pass by outer peripheries of the cooling pipes so that the external air can be exhausted together with the exhaust gas through the chimney.
- the release agent comprise 90 to 99.5 wt% of porous expansion ceramic, 0.5 to 9 wt% of binder, and 0 to 1 wt% of thickener.
- the porous expansion ceramic is preferably prepared by calcining at least one rock component selected from the group consisting of obsidian, perlite, pitchstone, vermiculite, pumice and shale at a temperature range of 900 to l,600°C.
- lime or activated carbon powder may be used as the chemical powder.
- FIG. 1 is a schematic view of a hybrid- type scrubbing apparatus having a condenser according to an embodiment of the present invention.
- FIG. 2 is a perspective view of an example of an eliminator used in the hybrid-type scrubbing apparatus having a condenser according to the present invention.
- FIG. 3 shows various arrangement states of spray nozzles and eliminators in the hybrid-type scrubbing apparatus having a condenser according to the present invention.
- FIG. 4 is a detailed view of a bag filter of a dry scrubbing means in the hybrid- type scrubbing apparatus having a condenser according to the present invention.
- Fig. 1 is a schematic view of a hybrid-type scrubbing apparatus having a condenser according to an embodiment of the present invention.
- the apparatus for scrubbing exhaust gas comprises a wet scrubbing means A for primarily scrubbing acid exhaust gas by spraying an alkaline chemical solution to the exhaust gas; a dry scrubbing means B for secondly scrubbing the primarily scrubbed exhaust gas to remove hazardous substances remaining therein by passing the exhaust gas through a bag filter to which releasing agent and lime powder are supplied; a condenser C for scrubbing the exhaust gas, which has passed through the dry scrubbing means B, to malodor and VOCs by condensing moisture remaining in the exhaust gas; and a blower connected to the condenser C to blow out the exhaust gas through a chimney.
- the wet scrubbing means A comprises a wet scrubbing chamber 10 provided with an inlet 17 through which exhaust gas is introduced and an outlet 12 through which treated exhaust gas flows out; a pair of eliminators 11 disposed within the wet scrubbing chamber to divide the interior of the wet scrubbing chamber into an inlet- side space and an outlet-side space; an oil/water separation tank 20 comprising a plurality of reservoirs for scrubbing liquid containing dust and the like discharged from the wet scrubbing chamber 10; a concentrating tank 50 for concentrating sludge precipitated in the oil/water separation tank 20; and a dehydrator 70 for separating remaining liquid from the concentrated sludge. Furthermore, the wet scrubbing means A comprises spray nozzles 18 installed to spray liquid into the inlet-side space of the wet scrubbing chamber 10.
- An installation stand 14 is fixed at a lower portion of the wet scrubbing chamber 10 so as to install the eliminators such that the eliminators are spaced apart by a predetermined distance from the bottom of the wet scrubbing chamber. Furthermore, the wet scrubbing chamber 10 is disposed such that exhaust gas introduced into the wet scrubbing chamber through the inlet 17 flows horizontally toward the outlet 12, and the eliminators 11 are installed perpendicularly to the flow of the exhaust gas. Furthermore, a drain hole 13 for drainage of liquid collected on the bottom of the wet scrubbing chamber 10 is formed at a position on a side wall of the wet scrubbing chamber 10, which corresponds to a level higher than that of the bottoms of the eliminators 11. Furthermore, a drainpipe 15 for cleaning is connected to the bottom of the wet scrubbing chamber 10, and a valve 16 for closing the drainpipe 15 upon use of the wet scrubbing chamber is installed at the drainpipe 15.
- the eliminators 11 installed in the wet scrubbing chamber 10 are disposed within the wet scrubbing chamber 10 to divide the scrubbing chamber 10 into the inlet-side space and the outlet-side space.
- the eliminators 11 are installed such that the bottoms thereof are mounted on the installation stand 14 positioned below the drain hole 13 and side surfaces of the eliminators 11 except the bottoms thereof are in close contact with an inner surface of the wet scrubbing chamber 10. Therefore, moisture separated from exhaust gas, which passes through the eliminators 11, flows to and is collected at the lower portion of the wet scrubbing chamber 10, and the collected moisture is discharged to a first reservoir 20a of the oil/water separation tank 20 through a drainpipe 19 connected to the drain hole 13.
- FIG. 2 a perspective view of an example of an eliminator used in the hybrid-type scrubbing apparatus according to the present invention.
- the eliminator 11 comprises an upper plate l la with handles installed thereon, a frame 1 Id for receiving a plurality of blades 1 Ib, a lower plate 1 Ic, and the plurality of blades 1 Ib installed at the upper plate l la and the lower plate 1 Ic.
- the plurality of blades 1 Ib are vertically disposed so that moisture or dust removed from the exhaust gas falls onto the bottom of the wet scrubbing chamber 10 by gravity.
- the respective blades 1 Ib are bent so that particulates can be removed by guiding a flow direction of the exhaust gas.
- installation grooves 1 Ic-I in which the blades 1 Ib are installed are formed in the upper plate l la and the lower plate l ie.
- Fig. 3 shows various arrangement states of the spray nozzles and the eliminators in the hybrid-type scrubbing apparatus according to the present invention.
- the spray nozzles 18 may be installed (contrary to those shown in Fig. 1) such that a liquid spray direction of the spray nozzles faces in a downstream direction of the flow of exhaust gas (a direction designated by arrows) as shown in Fig. 3a, pairs of spray nozzles 18 may be installed such that spray directions thereof are opposite to each other as shown in Fig. 3b, or spray nozzles may be installed between the plurality of eliminators 11 as shown in Fig. 3c.
- Natural flow piping or a pump 40 for discharging the precipitated sludge is connected to the bottoms of the respective reservoirs of the oil/water separation tank 20.
- the pump sucks the sludge and feeds it to the concentrating tank 50.
- the sludge concentrated in the concentrating tank 50 is sent to the dehydrator 70 through a pump 60 connected to a pipe 61.
- the dehydrator 70 separates remaining liquid from the sludge and sends it to the reservoir 2Of of the oil/water separation tank 20, and separately discharges a cake of sludge that is to be disposed of.
- the wet scrubbing means A of this embodiment further comprises a device for spraying an alkaline solution through the spray nozzles 18 into the wet scrubbing chamber 10.
- the exhaust gas contains SOx, NOx, HCl, dioxin, and/or other hazardous substances.
- the wet scrubbing means A neutralizes the acid exhaust gas by spraying an alkaline chemical into the wet scrubbing chamber, and passing the exhaust gas through the eliminators to remove moisture and dust from the exhaust gas.
- a calcium based (Ca(OH) , CaO and CaCO ) solution and a sodium based (NaHCO , NaOH and Na CO ) solution can be
- the sodium based solution is preferably used since upon use of the calcium based solution, a reaction product has low solubility as compared with the sodium based solution, resulting in formation of a great deal of scale in a reactor due to precipitation.
- Dust is removed by inertial impaction with droplets of a sodium hydroxide solution sprayed from the nozzles in the wet scrubbing chamber or interception by particles of the droplets, and fine particles are removed while passing through the eliminators by colliding with the droplets due to diffusion resulting from Brownian movement, and other gravity, electrostatic force, and the like.
- the wet scrubbing means A of this embodiment comprises installations for injecting a controlled alkaline chemical such as sodium hydroxide (NaOH) so that a solution in the reservoir 2Of, which has been previously sprayed by the spray nozzles 18 to neutralize the acid exhaust gas and to remove hazardous particle substances such as dust contained in the exhaust gas, can be maintained at a proper pH value. That is, the wet scrubbing means further comprises a chemical storage tank 80 for storing an alkaline chemical therein, a pH sensor 81 installed in the reservoir 2Of of the oil/water separation tank 20, and a chemical feed pump 83 and pipes 82 and 84 for feeding the chemical stored in the chemical storage tank 80 to the reservoir 2Of.
- a controlled alkaline chemical such as sodium hydroxide (NaOH)
- the wet scrubbing means further comprises a controller for receiving a value measured by the pH sensor 81 and supplying the chemical to the reservoir 2Of by operating the chemical feed pump if the measured value is in a predetermined range.
- a controller for receiving a value measured by the pH sensor 81 and supplying the chemical to the reservoir 2Of by operating the chemical feed pump if the measured value is in a predetermined range.
- PLC programmable logic controller
- a general-purpose computer may be used as the controller.
- the wet scrubbing means A of this embodiment is constructed such that dust or moisture removed by the eliminators 11 fall into the first reservoir 20a of the oil/water separation tank 20 through the drain hole 13 of the wet scrubbing chamber 10.
- the oil/ water separation tank 20 comprises the plurality of reservoirs 20a to 2Of of which partitions walls are formed with penetration holes such that supernatant and subnatant alternately flow from one of the reservoirs to a neighboring reservoir through the penetration holes so as to precipitate sludge. Therefore, particles such as dust are all precipitated in intermediate reservoirs so that scrubbed clean supernatant can flow into the final reservoir 2Of.
- a pump 30 is connected to the final reservoir 2Of through a pipe 31, and the pump supplies a scrubbed solution to the spray nozzles 18 installed in the wet scrubbing chamber 10. Accordingly, the spray nozzles 18 are prevented from being clogged.
- the entire exhaust gas containing the sprayed moisture passes through the eliminators and is then exhausted through the outlet in a state where the moisture has been removed from the exhaust gas, thereby preventing excessive loss of moisture. Therefore, there is a little need for replenishment of a solution to be sprayed.
- clogging of the nozzles due to sludge is prevented by completely scrubbing the sludge in the oil/water separation tank. Further, since the sludge is separately concentrated and discharged in a form of a cake and a solution is circulated and then reused, wastewater is not discharged, resulting in a contribution to environmental conservation.
- the dry scrubbing means B removes hazardous substances remaining in the exhaust gas while the exhaust gas is passed through a chemical layer and a releasing agent layer attached to the surface of a bag of a bag filter.
- the exhaust gas may be passed through a bag of the bag filter of which the surface has no releasing agent and chemical powder attached thereto.
- Lime powder, activated carbon powder, zeolite powder, diatomite powder or a mixture thereof obtained by mixing them at a proper mixing ratio can be used for the chemical layer according to the type and concentration of the exhaust gas. It is preferred that lime be used to scrub acid exhaust gas.
- the release agent layer formed of powder of a composition comprising porous expansion ceramic, a binder and a thickener is not solidified or plasterized on the surface of the bag even though the exhaust gas containing a large amount of moisture passes through the release agent layer. Therefore, even though the lime layer (chemical layer) for removing the hazardous components remaining in the exhaust gas is plasterized, application of pulsed air under high pressure within the bag allows the lime layer to be easily separated along with an outer lime layer of the bag. Accordingly, hazardous exhaust gas containing a large amount of moisture or sticky particulate matters can be filtered to collect dust from the exhaust gas, thereby scrubbing the exhaust gas.
- HAPs hazardous substances
- certain hazardous substances such as dioxin and heavy metals are collected and removed while passing through the lime layer, the release agent layer and the bag of the bag filter by means of inertial impaction, direct interception or diffusion in a state that some of the hazardous substances are adsorbed by the lime layer, and some of them are adsorbed by dust.
- some of the HAPs that are not removed through a reaction with the lime layer may be adsorbed and removed by activated carbon injected in front of the bag filter.
- NaClO as an additive is injected in front of the bag filter to improve the efficiency of removal of NO, scrubbing treatment is performed according to the following reaction equations 10 and 11.
- dioxin and dust are removed by inertial impaction and interception while passing through the lime layer, the release agent layer and the bag, and fine particles are removed by diffusion due to Brownian movement, and other gravity, electrostatic force and the like.
- the dry scrubbing means B of this embodiment comprises a duct 2 with one end connected to the outlet 12 of the wet scrubbing chamber 10, a bag filter 90 connected to the other end of the duct 2, and a powder supply means connected to the duct 2 to supply release agent powder and lime powder to the bag filter 90 through the duct 2.
- the powder supply means comprises a releasing agent hopper 95 for storing a releasing agent therein and a lime hopper 96 for storing lime therein.
- the respective hoppers are installed such that they are connected to the duct 2 to independently supply releasing agent powder and lime powder.
- screw conveyors for crushing and transferring powder be installed on pipes 97 and 98, respectively.
- the bag filter 90 comprises a plurality of bags 92 installed therein, and a baffle 91 installed between the bags 92 and an inlet with the duct 2 connected thereto.
- the release agent powder be neutral, have a low specific gravity of 0.12 ton/D and a porosity of 85 to 95%, and be hardly plasterized even though moisture is absorbed into the release agent powder, and components thereof comprise silica (SiO ) as a drying/damp-proofing agent, alumina (Al O ) as an adsorbing/dehydrating agent, potassium oxide (K O) as a catalyst reacting with water, sodium oxide (Na O) as a reducer/catalyst, calcium oxide (CaO) as a moisture capturing/drying agent, and iron oxide (Fe O ) as a moisture adsorbent.
- silica SiO
- Al O alumina
- K O potassium oxide
- K O potassium oxide
- Na O sodium oxide
- CaO calcium oxide
- Fe O iron oxide
- the release agent comprising the aforementioned components preferably has the following composition: 69 to 79.5 wt% of silica, 10.9 to 17 wt% of alumina, 0.5 to 6.4 wt% of potassium oxide, 1.5 to 3.7 wt% of sodium oxide, 0.1 to 1.0 wt% of calcium oxide and 0.1 to 2.0 wt% of iron oxide.
- the lime layer 92b is formed of a mixture of lime and at least one selected from activated carbon, silica gel, starch, bentonite, alumina, diatomite, zeolite, perlite, and ceramic powder according to air pollutants. Furthermore, since particles of the release agent powder are larger than those of lime powder as shown in Fig. 4, pores of the release agent layer 92a are larger than those of the lime layer 92b.
- a discharge port is formed at a lower portion of the bag filter 90 to drain the release agent and lime removed from the bags, and a rotary valve 93 is installed at the discharge port.
- the rotary valve 93 comprises a plurality of blades 93a formed at a predetermined interval along the circumference of the rotary valve 93, and discharges the release agent and lime removed in the bag filter to the outside by rotation of the plurality of blades 93a.
- the rotary valve 93 and the baffle 91 enable uniform formation of the release agent layer 92a and the lime layer 92b when the blower 110 sucks air from the interior of the bag filter 90 to form a vacuum state therein and the release agent and the lime powder are sequentially supplied through the duct 2 to form the release agent layer 92a and the lime layer 92b in the bag 92.
- Reference numeral 93b designates a resin blade that adjusts a gap between a housing of the bag filter and the blade 93a and is installed to be simply exchanged when the blade 93b is worn out.
- the condenser C prevents generation of malodor and white smoke by condensing and removing moisture and impurities such as VOCs remaining in the exhaust gas that has passed through the bag filter 90.
- the condenser C comprises a condensation chamber 100, and a plurality of cooling pipes 101 installed in the condensation chamber 100 such that the exhaust gas passes by the cooling pipes 101.
- the condenser C comprises a second blower 106 for sucking external air and causing the external air to pass by outer peripheries of the cooling pipes and exhausting the external air together with the exhaust gas through the chimney.
- a filter for removing dust introduced from the outside is installed at an inlet pipe 102 through which the external air is introduced by the second blower 106, and an outlet pipe 105 is connected to the condensation chamber 100 such that the external air introduced into the condensation chamber 100 comes into contact with and passes by the outer peripheries of the cooling pipes 101 and is then exhausted through the chimney via the outlet pipe 105.
- a pipe 103 for discharging condensate is connected to a lower portion of the condensation chamber 100, and a valve 104 is installed on the pipe 103.
- the rotary valve 93 is simultaneously operated to intermittently supply external air into the bag filter through the clearances C between the housing of the bag filter and the blades 93a so that the powder can uniformly adhere to the surface of the bag 92.
- the rotation of the rotary valve 93 supplies the external air so that the supplied powder can fly upward, thereby causing all the supplied powder to adhere to the bag 92 of the bag filter 90.
- the exhaust gas introduced into the wet scrubbing chamber 10 by the operation of the blower 110 is neutralized by reacting with a solution into which an alkaline chemical sprayed from the spray nozzles 18 is dissolved, according to the reaction equations 1 to 4.
- the neutralized exhaust gas passes through the eliminators 11 where dust or moisture is removed therefrom, and is then exhausted through the outlet 12. Dust, neutralized salts, moisture and condensate contained in the exhaust gas, which have been removed by the eliminators 11, are collected on the bottom of the wet scrubbing chamber 10.
- a solution with the chemical dissolved therein is always filled in the space between the bottoms of the eliminators 11 and the bottom of the wet scrubbing chamber 10 so that the exhaust gas cannot pass through the space.
- the exhaust gas is exhausted through the outlet 12 in a state where dust or moisture is always removed from the exhaust gas through the eliminators 11.
- the moisture which flows to and is collected on the bottom of the wet scrubbing chamber 10, is discharged to the first reservoir 20a of the oil/water separation tank 20 through the drainpipe 19 connected to the drain hole 13.
- Dust and reaction salts contained in the solution are precipitated onto the bottom of the oil/water separation tank 20 while the solution is sequentially scrubbed in the oil/water separation tank 20. Sludge precipitated onto the bottom of the oil/water separation tank 20 is sent to the concentrating tank 50 through the pump 40, and the sludge is concentrated in the concentrating tank.
- the concentrated sludge is dehydrated in the dehydrator 70, and a cake of sludge is then discharged and disposed of. Liquid collected through dehydration in the dehydrator 70 is sent to and reused in the oil/water separation tank 20. If a value measured by the pH sensor 81 installed at the oil/water separation tank 20 is out of a predetermined range, a controller (not shown) operates the pump 83 so that the chemical stored in the tank 80 can be supplied to the oil/water separation tank 20.
- the exhaust gas which has been primarily scrubbed by the wet scrubbing means A and supplied to the bag filter 90 of the dry scrubbing means B is secondly scrubbed by passing through the lime layer 92b such that residual acid gas is neutralized and dust or other impurities are adsorbed onto the lime layer or trapped in pores of the lime layer 92b. If pressure loss in the filter 92 increases due to clogging of the pores of the release agent layer and the lime layer as the bag filter 90 is continuously used for exhaust gas treatment, high-pressure air is supplied into the bag 92 to separate the release agent layer and the lime layer from the bag.
- the release agent layer is not plasterized even though it absorbs moisture, the release agent layer is easily separated from the bag when the high-pressure air is applied in a pulse manner to the bag for the separation of the release agent layer. Therefore, the lime layer adhering to the release agent layer is also easily separated from the bag. Accordingly, when the bag is cleaned and a fresh release agent and lime are then caused to adhere to the bag as described above, the bag of the bag filter can be used semi-permanently. Since technical contents of a dedusting means for removing dust adhering to the bag 92 of the bag filter 90 are known in the art, detailed descriptions thereof will be omitted.
- a hybrid-type apparatus for treating exhaust gas having a condenser wherein exhaust gas containing hazardous substances is primarily neutralized by spraying an alkaline chemical solution to the exhaust gas, secondly passed through a simple bag filter or a bag filter to which a releasing agent layer and a chemical layer are attached to remove residual hazardous substances from the exhaust gas, and thirdly passed through the condenser to remove white smoke and malodor.
- the drain hole is formed at a position higher than the bottoms of the eliminators installed in the wet scrubbing chamber, so that moisture and dust of exhaust gas can be more efficiently removed. Furthermore, a solution containing the dust removed from the exhaust gas is scrubbed in the oil/water separation tank comprising a plurality of treatment reservoirs, thereby preventing the nozzles from being clogged. Furthermore, remaining liquid contained in sludge discharged from the oil/water separation tank is separated by the dehydrator and then reused. Thus, wastewater is not discharged, resulting in a contribution to environmental conservation.
- scrubbing apparatus primarily wet-scrubbed exhaust gas is subjected to secondary dry scrubbing by being supplied directly to a simple bag filter or a bag filter with a bag to which a non-plasterized releasing agent and chemical powder such as lime are sequentially attached, thereby effectively scrubbing the exhaust gas and simultaneously reducing construction and maintenance of facilities.
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Abstract
The present invention relates to an apparatus for treating exhaust gas exhausted from thermal installations such as a hazardous substance drying apparatus, a municipal solid waste incinerator and a furnace. The apparatus for treating exhaust gas according to the present invention comprises a wet scrubbing means for primarily scrubbing acid exhaust gas by spraying an alkaline chemical solution to the exhaust gas, a dry scrubbing means for secondly scrubbing the primarily-scrubbed exhaust gas by passing the exhaust gas through a simple bag filter or a bag filter to which a release agent and lime powder are supplied, to remove hazardous substances remaining in the exhaust gas, a condenser for condensing moisture remaining in the exhaust gas, which has passed through the dry scrubbing means, to remove malodor and volatile organic compounds, and a second blower for introducing external air into the condenser. In the apparatus for treating exhaust gas according to the present invention, there is no need for installation of an additional combustion system for preventing generation of malodor or white smoke, and a simple bag filter is used or a bag of the bag filter to which a non-plasterized releasing agent and chemical powder such as lime are sequentially attached is used semi-permanently. Thus, construction and maintenance costs of facilities can be reduced. Further, since an air-cooling type condenser is installed at the rear of the dry scrubbing means, generation of malodor and white smoke is prevented. Therefore, various kinds of hazardous exhaust gas can be completely scrubbed and then exhausted to the atmosphere.
Description
Description
HYBRID-TYPE APPARATUS FOR TREATING EXHAUST GAS
HAVING A CONDENSER
Technical Field
[1] The present invention relates to an apparatus for treating exhaust gas exhausted from thermal installations such as a hazardous substance drying apparatus, a municipal solid waste incinerator and a furnace. More particularly, the present invention relates to a hybrid- type apparatus for treating exhaust gas, wherein an alkaline chemical solution is first sprayed to exhaust gas so as to neutralize the exhaust gas, the exhaust gas is secondly passed through a bag filter or a bag filter with a release agent layer and a chemical layer adhering thereto so as to remove residual hazardous substances of the exhaust gas, and the exhaust gas is thirdly passed through a condenser so as to remove white smoke and malodor. Background Art
[2] Exhaust gas generated from an incinerator for incinerating municipal solid wastes or industrial wastes contains hazardous substances such as dust, acid gases (HCl, SOx, NOx, HF, etc.), heavy metals (Hg, Cd, Pb, As, Zn, etc.), and dioxin. Furthermore, exhaust gas exhausted upon drying of food garbage or hazardous substances also contains a large amount of dust or noxious gases and malodorous fine dust. Particularly, exhaust gas generated upon drying of food garbage or hazardous substances contains volatile organic compounds (VOCs) that generate smog through photochemical reaction and are the cause of malodor.
[3] Conventional methods for treating such hazardous exhaust gas include a method in which an alkaline solution is sprayed to exhaust gas to remove dust therefrom or neutralize the exhaust gas in a wet process and the exhaust gas is incinerated in a de- odorization furnace, subsequently dehydrated to remove moisture therefrom and then exhausted, and a method in which a lime slurry is supplied to exhaust gas to neutralize the exhaust gas in a semi-dry process, the neutralized exhaust gas is passed through a bag filter to remove dust therefrom and then exhausted. In order to prevent generation of malodor and white smoke by removing VOCs, additional equipment for burning the VOCs using a catalyst may be installed at the rear of a scrubber.
[4] On the other hand, Korean Patent Application No. 10-2004-0093768 filed in the name of the applicant and entitled Hybrid-type apparatus for treating exhaust gas discloses a method and apparatus for treating exhaust gas by wet-scrubbing acid exhaust gas containing dust and directly passing the wet-scrubbed exhaust gas through a bag filter (hereinafter, a method for treating exhaust gas by wet-scrubbing acid
exhaust gas containing dust and directly passing the wet-scrubbed exhaust gas through a bag filter is referred to as a hybrid-type method for treating exhaust gas ). Furthermore, Korean Patent Application No. 10-2005-0026074 filed in the name of the applicant and entitled Wet type apparatus for scrubbing exhaust gas discloses a wet scrubbing apparatus capable of improving the efficiency of removal of dust, mist, moisture, condensate and the like from exhaust gas and preventing generation of wastewater and clogging of spray nozzles in a scrubbing chamber. All technical contents of the exhaust gas scrubbing apparatuses disclosed in the aforementioned patent applications are incorporated herein as a part of the present invention.
[5]
Disclosure of Invention Technical Problem
[6] The present invention is conceived on an extension line of the aforementioned inventions of the Korean patent applications filed in the name of the applicant. An object of the present invention is to provide a hybrid-type apparatus for treating exhaust gas, wherein various kinds of hazardous exhaust gas can be completely scrubbed and then exhausted to the atmosphere. Particularly, an object of the prevent invention is to provide an apparatus for treating exhaust gas having a condenser, wherein VOCs or malodor can be removed and generation of white smoke can be prevented without installation of an additional catalytic combustion device. Furthermore, an object of the present invention is to provide a hybrid-type apparatus for treating exhaust gas, wherein releasing agent powder and chemical powder are supplied to a bag filter to completely remove hazardous substances of exhaust gas and the bag filter can be used semi-permanently, thereby improving economical efficiency due to low maintenance costs. Technical Solution
[7] A hybrid-type apparatus for treating exhaust gas according to the present invention comprises a wet scrubbing means including a wet scrubbing chamber that has an inlet through which exhaust gas is introduced, an outlet through which treated exhaust gas flows out, and a drain hole formed at a position in a side surface thereof spaced apart by a certain distance upwardly from the bottom thereof, and is disposed such that the exhaust gas introduced through the inlet horizontally flows toward the outlet, an eliminator that is disposed within the wet scrubbing chamber to divide the interior of the wet scrubbing chamber into an inlet-side space and an outlet-side space, has a plurality of bent blades arranged to form a passage for the exhaust gas, and is installed such that the bottom thereof is positioned below the drain hole, and a spray nozzle for spraying liquid into the inlet-side space of the wet scrubbing chamber; a dry scrubbing
means including a duct having one end connected to the outlet of the wet scrubbing chamber, a bag filter connected to the other end of the duct, and a powder supply means connected to the duct so as to supply release agent powder and chemical powder to the bag filter through the duct; a condenser for receiving the exhaust gas exhausted from the bag filter and condensing moisture contained in the exhaust gas to remove the moisture therefrom; and a blower connected to the condenser to blow out the exhaust gas through a chimney, wherein the powder supply means supplies the release agent powder to the duct during operation of the blower to cause the release agent powder to adhere to a surface of a bag of the bag filter so as to form a release agent layer with a predetermined thickness and subsequently supplies the chemical powder to cause the chemical powder to adhere to a surface of the release agent layer so as to form a chemical layer with a predetermined thickness, and the spray nozzle sprays liquid into the wet scrubbing chamber, whereby the exhaust gas is primarily scrubbed in the wet scrubbing means, secondly scrubbed in the dry scrubbing means, thirdly passed through the condenser to remove the moisture, and then exhausted.
[8] The wet scrubbing means may further comprise an oil/water separation tank including a plurality of reservoirs to scrub liquid received from the drain hole by sequentially passing the liquid through the plurality of reservoirs; a concentrating tank for receiving sludge precipitated in the oil/water separation tank and concentrating the sludge therein; and a dehydrator for receiving the concentrated sludge from the concentrating tank, separating remaining liquid from the concentrated sludge, supplying the separated liquid to one of the reservoirs of the oil/water separation tank, and discharging a cake of sludge obtained through the separation of the remaining liquid. The spray nozzle may be installed to receive liquid from a final treatment reservoir of the reservoirs of the oil/water separation tank and to spray the liquid into the inlet-side space of the wet scrubbing chamber. Further, the wet scrubbing means may be adapted to supply an alkaline chemical to the oil/water separation tank to scrub acid exhaust gas. That is, the wet scrubbing means may further comprise a pH sensor installed at the oil/water separation tank; an alkali chemical storage tank; a chemical feed pump connected to the storage tank to feed an alkali chemical to the oil/water separation tank; and a controller for receiving a value measured by the pH sensor and supplying the chemical to the oil/water separation tank by operating the chemical feed pump if the measured value is in a predetermined range.
[9] Preferably, the bag filter includes a baffle installed between an inlet connected to the duct and the bag, and a rotary valve installed at a lower portion of the bag filter, the rotary valve includes a plurality of blades arranged at a predetermined interval along the circumference of the rotary valve, and the rotary valve is rotated at a predetermined speed to intermittently supply external air from the lower portion of the bag filter when
the chemical spray means supplies the release agent powder and the chemical powder to the bag filter, so that the release agent powder and the chemical powder can uniformly adhere to the surface of the bag.
[10] Furthermore, the condenser preferably comprises a condensation chamber in which a plurality of cooling pipes are installed such that the exhaust gas supplied from the bag filter passes by the cooling pipes, and a second blower installed to suck external air and to cause the external air to pass by outer peripheries of the cooling pipes so that the external air can be exhausted together with the exhaust gas through the chimney.
[11] Moreover, it is preferred that the release agent comprise 90 to 99.5 wt% of porous expansion ceramic, 0.5 to 9 wt% of binder, and 0 to 1 wt% of thickener. The porous expansion ceramic is preferably prepared by calcining at least one rock component selected from the group consisting of obsidian, perlite, pitchstone, vermiculite, pumice and shale at a temperature range of 900 to l,600°C. Furthermore, lime or activated carbon powder may be used as the chemical powder. Brief Description of the Drawings
[12] Fig. 1 is a schematic view of a hybrid- type scrubbing apparatus having a condenser according to an embodiment of the present invention.
[13] Fig. 2 is a perspective view of an example of an eliminator used in the hybrid-type scrubbing apparatus having a condenser according to the present invention.
[14] Fig. 3 shows various arrangement states of spray nozzles and eliminators in the hybrid-type scrubbing apparatus having a condenser according to the present invention.
[15] Fig. 4 is a detailed view of a bag filter of a dry scrubbing means in the hybrid- type scrubbing apparatus having a condenser according to the present invention.
[16] <Brief Explanation of Reference Numerals in the Drawings>
[17] 10: Wet scrubbing chamber 11: Eliminator
[18] 20: Oil/water separation tank 50: Concentrating tank
[19] 70: Dehydrator 80: Chemical tank
[20] 81 : pH sensor 90: Bag filter
[21] 91 : B affle 95 : Releasing agent hopper
[22] 96: Lime hopper 100: Condenser
[23]
Best Mode for Carrying Out the Invention
[24] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[25] Fig. 1 is a schematic view of a hybrid-type scrubbing apparatus having a condenser according to an embodiment of the present invention.
[26] The apparatus for scrubbing exhaust gas according to this embodiment comprises a wet scrubbing means A for primarily scrubbing acid exhaust gas by spraying an alkaline chemical solution to the exhaust gas; a dry scrubbing means B for secondly scrubbing the primarily scrubbed exhaust gas to remove hazardous substances remaining therein by passing the exhaust gas through a bag filter to which releasing agent and lime powder are supplied; a condenser C for scrubbing the exhaust gas, which has passed through the dry scrubbing means B, to malodor and VOCs by condensing moisture remaining in the exhaust gas; and a blower connected to the condenser C to blow out the exhaust gas through a chimney.
[27] The wet scrubbing means A comprises a wet scrubbing chamber 10 provided with an inlet 17 through which exhaust gas is introduced and an outlet 12 through which treated exhaust gas flows out; a pair of eliminators 11 disposed within the wet scrubbing chamber to divide the interior of the wet scrubbing chamber into an inlet- side space and an outlet-side space; an oil/water separation tank 20 comprising a plurality of reservoirs for scrubbing liquid containing dust and the like discharged from the wet scrubbing chamber 10; a concentrating tank 50 for concentrating sludge precipitated in the oil/water separation tank 20; and a dehydrator 70 for separating remaining liquid from the concentrated sludge. Furthermore, the wet scrubbing means A comprises spray nozzles 18 installed to spray liquid into the inlet-side space of the wet scrubbing chamber 10.
[28] An installation stand 14 is fixed at a lower portion of the wet scrubbing chamber 10 so as to install the eliminators such that the eliminators are spaced apart by a predetermined distance from the bottom of the wet scrubbing chamber. Furthermore, the wet scrubbing chamber 10 is disposed such that exhaust gas introduced into the wet scrubbing chamber through the inlet 17 flows horizontally toward the outlet 12, and the eliminators 11 are installed perpendicularly to the flow of the exhaust gas. Furthermore, a drain hole 13 for drainage of liquid collected on the bottom of the wet scrubbing chamber 10 is formed at a position on a side wall of the wet scrubbing chamber 10, which corresponds to a level higher than that of the bottoms of the eliminators 11. Furthermore, a drainpipe 15 for cleaning is connected to the bottom of the wet scrubbing chamber 10, and a valve 16 for closing the drainpipe 15 upon use of the wet scrubbing chamber is installed at the drainpipe 15.
[29] The eliminators 11 installed in the wet scrubbing chamber 10 are disposed within the wet scrubbing chamber 10 to divide the scrubbing chamber 10 into the inlet-side space and the outlet-side space. The eliminators 11 are installed such that the bottoms thereof are mounted on the installation stand 14 positioned below the drain hole 13 and side surfaces of the eliminators 11 except the bottoms thereof are in close contact with an inner surface of the wet scrubbing chamber 10. Therefore, moisture separated from
exhaust gas, which passes through the eliminators 11, flows to and is collected at the lower portion of the wet scrubbing chamber 10, and the collected moisture is discharged to a first reservoir 20a of the oil/water separation tank 20 through a drainpipe 19 connected to the drain hole 13. Since the bottoms of the eliminators 11 are positioned below the drain hole 13, water or a chemical solution is always filled in a space between the bottoms of the eliminators 11 and the bottom of the wet scrubbing chamber 10 so that the exhaust gas cannot pass through the space. Therefore, the exhaust gas is exhausted through the outlet 12 in a state where moisture is always removed from the exhaust gas through the eliminators 11.
[30] Fig. 2 a perspective view of an example of an eliminator used in the hybrid-type scrubbing apparatus according to the present invention. Referring to Fig. 2, the eliminator 11 comprises an upper plate l la with handles installed thereon, a frame 1 Id for receiving a plurality of blades 1 Ib, a lower plate 1 Ic, and the plurality of blades 1 Ib installed at the upper plate l la and the lower plate 1 Ic. The plurality of blades 1 Ib are vertically disposed so that moisture or dust removed from the exhaust gas falls onto the bottom of the wet scrubbing chamber 10 by gravity. Furthermore, the respective blades 1 Ib are bent so that particulates can be removed by guiding a flow direction of the exhaust gas. Moreover, installation grooves 1 Ic-I in which the blades 1 Ib are installed are formed in the upper plate l la and the lower plate l ie.
[31] Fig. 3 shows various arrangement states of the spray nozzles and the eliminators in the hybrid-type scrubbing apparatus according to the present invention. The spray nozzles 18 may be installed (contrary to those shown in Fig. 1) such that a liquid spray direction of the spray nozzles faces in a downstream direction of the flow of exhaust gas (a direction designated by arrows) as shown in Fig. 3a, pairs of spray nozzles 18 may be installed such that spray directions thereof are opposite to each other as shown in Fig. 3b, or spray nozzles may be installed between the plurality of eliminators 11 as shown in Fig. 3c.
[32] Natural flow piping or a pump 40 for discharging the precipitated sludge is connected to the bottoms of the respective reservoirs of the oil/water separation tank 20. In case of the pump 40, the pump sucks the sludge and feeds it to the concentrating tank 50. The sludge concentrated in the concentrating tank 50 is sent to the dehydrator 70 through a pump 60 connected to a pipe 61. The dehydrator 70 separates remaining liquid from the sludge and sends it to the reservoir 2Of of the oil/water separation tank 20, and separately discharges a cake of sludge that is to be disposed of.
[33] For neutralization of acid exhaust gas, the wet scrubbing means A of this embodiment further comprises a device for spraying an alkaline solution through the spray nozzles 18 into the wet scrubbing chamber 10.
[34] In case of acid exhaust gas, the exhaust gas contains SOx, NOx, HCl, dioxin, and/or
other hazardous substances. In order to treat the acid exhaust gas, the wet scrubbing means A neutralizes the acid exhaust gas by spraying an alkaline chemical into the wet scrubbing chamber, and passing the exhaust gas through the eliminators to remove moisture and dust from the exhaust gas. Although a calcium based (Ca(OH) , CaO and CaCO ) solution and a sodium based (NaHCO , NaOH and Na CO ) solution can be
3 3 2 3 used as the alkaline chemical, the sodium based solution is preferably used since upon use of the calcium based solution, a reaction product has low solubility as compared with the sodium based solution, resulting in formation of a great deal of scale in a reactor due to precipitation.
[35] If sodium hydroxide (NaOH) is used as a chemical in the wet treatment process, acid exhaust gas is neutralized according to the following reaction equations 1 to 4. Although sulfur dioxide or hydrogen chloride easily dissolved in water or an alkaline solution is easily removed in the wet treatment process, NO, dioxin and other hazardous gases that are not easily dissolved in water or an alkaline solution are hardly removed in the wet treatment process but exhausted as they are. Thus, there is a need for an additional treatment process. Dust is removed by inertial impaction with droplets of a sodium hydroxide solution sprayed from the nozzles in the wet scrubbing chamber or interception by particles of the droplets, and fine particles are removed while passing through the eliminators by colliding with the droplets due to diffusion resulting from Brownian movement, and other gravity, electrostatic force, and the like.
[36] [Reaction Equation 1]
[37] SO + 2NaOH => Na SO + H O
2 2 3 2
[38] [Reaction Equation 2]
[39] SO 2 + NaOH ^ NaHSO 3
[40] [Reaction Equation 3]
[41 ] HCl + 2NaOH => NaCl + H O
[42] [Reaction Equation 4]
[43] NO + 2NaOH + 1/20 2 => Na 2 (NO 3 ) 2
[44] The wet scrubbing means A of this embodiment comprises installations for injecting a controlled alkaline chemical such as sodium hydroxide (NaOH) so that a solution in the reservoir 2Of, which has been previously sprayed by the spray nozzles 18 to neutralize the acid exhaust gas and to remove hazardous particle substances such as dust contained in the exhaust gas, can be maintained at a proper pH value. That is, the wet scrubbing means further comprises a chemical storage tank 80 for storing an alkaline chemical therein, a pH sensor 81 installed in the reservoir 2Of of the oil/water separation tank 20, and a chemical feed pump 83 and pipes 82 and 84 for feeding the chemical stored in the chemical storage tank 80 to the reservoir 2Of. Moreover, although not shown in the figure, the wet scrubbing means further comprises a
controller for receiving a value measured by the pH sensor 81 and supplying the chemical to the reservoir 2Of by operating the chemical feed pump if the measured value is in a predetermined range. Typically, a programmable logic controller (PLC) can be used as the controller. However, a general-purpose computer may be used as the controller.
[45] The wet scrubbing means A of this embodiment is constructed such that dust or moisture removed by the eliminators 11 fall into the first reservoir 20a of the oil/water separation tank 20 through the drain hole 13 of the wet scrubbing chamber 10. The oil/ water separation tank 20 comprises the plurality of reservoirs 20a to 2Of of which partitions walls are formed with penetration holes such that supernatant and subnatant alternately flow from one of the reservoirs to a neighboring reservoir through the penetration holes so as to precipitate sludge. Therefore, particles such as dust are all precipitated in intermediate reservoirs so that scrubbed clean supernatant can flow into the final reservoir 2Of. A pump 30 is connected to the final reservoir 2Of through a pipe 31, and the pump supplies a scrubbed solution to the spray nozzles 18 installed in the wet scrubbing chamber 10. Accordingly, the spray nozzles 18 are prevented from being clogged.
[46] Further, in the wet scrubbing means of this embodiment, the entire exhaust gas containing the sprayed moisture passes through the eliminators and is then exhausted through the outlet in a state where the moisture has been removed from the exhaust gas, thereby preventing excessive loss of moisture. Therefore, there is a little need for replenishment of a solution to be sprayed. Moreover, in the wet scrubbing means of this embodiment, clogging of the nozzles due to sludge is prevented by completely scrubbing the sludge in the oil/water separation tank. Further, since the sludge is separately concentrated and discharged in a form of a cake and a solution is circulated and then reused, wastewater is not discharged, resulting in a contribution to environmental conservation.
[47] Next, the dry scrubbing means B will be described. The dry scrubbing means B removes hazardous substances remaining in the exhaust gas while the exhaust gas is passed through a chemical layer and a releasing agent layer attached to the surface of a bag of a bag filter. In a case where the exhaust gas is not acid exhaust gas, the exhaust gas may be passed through a bag of the bag filter of which the surface has no releasing agent and chemical powder attached thereto. Lime powder, activated carbon powder, zeolite powder, diatomite powder or a mixture thereof obtained by mixing them at a proper mixing ratio can be used for the chemical layer according to the type and concentration of the exhaust gas. It is preferred that lime be used to scrub acid exhaust gas. The release agent layer formed of powder of a composition comprising porous expansion ceramic, a binder and a thickener is not solidified or plasterized on the
surface of the bag even though the exhaust gas containing a large amount of moisture passes through the release agent layer. Therefore, even though the lime layer (chemical layer) for removing the hazardous components remaining in the exhaust gas is plasterized, application of pulsed air under high pressure within the bag allows the lime layer to be easily separated along with an outer lime layer of the bag. Accordingly, hazardous exhaust gas containing a large amount of moisture or sticky particulate matters can be filtered to collect dust from the exhaust gas, thereby scrubbing the exhaust gas.
[48] If a chemical layer formed of lime powder is used in the bag filter 90 of the dry scrubbing means B, acid exhaust gas is removed through neutralization according to the following reaction equations 5 to 9.
[49] [Reaction Equation 5]
[50] Ca(OH) 2 + SO 2 => CaSO 3 + H 2O
[53] [Reaction Equation 7]
[54] Ca(OH)2 + 4NO + 3O2 => 2Ca(NO3) + 2H2O
[55] [Reaction Equation 8]
[56] Ca(OH)2 + 2HCl => CaCl2 + 2H2O
[57] [Reaction Equation 9]
[58] Ca(OH) + 2HF => CaF + 2H O
[59] Furthermore, certain hazardous substances (HAPs) such as dioxin and heavy metals are collected and removed while passing through the lime layer, the release agent layer and the bag of the bag filter by means of inertial impaction, direct interception or diffusion in a state that some of the hazardous substances are adsorbed by the lime layer, and some of them are adsorbed by dust. In addition, some of the HAPs that are not removed through a reaction with the lime layer may be adsorbed and removed by activated carbon injected in front of the bag filter. Furthermore, if NaClO as an additive is injected in front of the bag filter to improve the efficiency of removal of NO, scrubbing treatment is performed according to the following reaction equations 10 and 11. Similarly to the exhaust gas passing through the wet scrubbing means A, dioxin and dust are removed by inertial impaction and interception while passing through the lime layer, the release agent layer and the bag, and fine particles are removed by diffusion due to Brownian movement, and other gravity, electrostatic force and the like.
[60] [Reaction Equation 10]
[61] 4NO + NaClO 2 + 2Ca(OH)2 => 2Ca(NO 2 )2 + NaCl + 2H 2O
[62] [Reaction Equation 11]
[63] 2SO 2 + NaClO 2 + 2Ca(OH) 2 => 2CaSO 4 + NaCl + 2H 2 O
[64] The dry scrubbing means B of this embodiment comprises a duct 2 with one end connected to the outlet 12 of the wet scrubbing chamber 10, a bag filter 90 connected to the other end of the duct 2, and a powder supply means connected to the duct 2 to supply release agent powder and lime powder to the bag filter 90 through the duct 2. The powder supply means comprises a releasing agent hopper 95 for storing a releasing agent therein and a lime hopper 96 for storing lime therein. The respective hoppers are installed such that they are connected to the duct 2 to independently supply releasing agent powder and lime powder. Although not shown in the figures, it is preferred that screw conveyors for crushing and transferring powder be installed on pipes 97 and 98, respectively.
[65] Moreover, as shown in Fig. 4, the bag filter 90 comprises a plurality of bags 92 installed therein, and a baffle 91 installed between the bags 92 and an inlet with the duct 2 connected thereto. A release agent layer 92a and a lime layer 92b respectively formed of the release agent powder and lime powder supplied through the duct 2 adhere to each of the bags 92. It is preferred that the release agent powder be neutral, have a low specific gravity of 0.12 ton/D and a porosity of 85 to 95%, and be hardly plasterized even though moisture is absorbed into the release agent powder, and components thereof comprise silica (SiO ) as a drying/damp-proofing agent, alumina (Al O ) as an adsorbing/dehydrating agent, potassium oxide (K O) as a catalyst reacting with water, sodium oxide (Na O) as a reducer/catalyst, calcium oxide (CaO) as a moisture capturing/drying agent, and iron oxide (Fe O ) as a moisture adsorbent. The release agent comprising the aforementioned components preferably has the following composition: 69 to 79.5 wt% of silica, 10.9 to 17 wt% of alumina, 0.5 to 6.4 wt% of potassium oxide, 1.5 to 3.7 wt% of sodium oxide, 0.1 to 1.0 wt% of calcium oxide and 0.1 to 2.0 wt% of iron oxide. Further, the lime layer 92b is formed of a mixture of lime and at least one selected from activated carbon, silica gel, starch, bentonite, alumina, diatomite, zeolite, perlite, and ceramic powder according to air pollutants. Furthermore, since particles of the release agent powder are larger than those of lime powder as shown in Fig. 4, pores of the release agent layer 92a are larger than those of the lime layer 92b.
[66] In addition, a discharge port is formed at a lower portion of the bag filter 90 to drain the release agent and lime removed from the bags, and a rotary valve 93 is installed at the discharge port. The rotary valve 93 comprises a plurality of blades 93a formed at a predetermined interval along the circumference of the rotary valve 93, and discharges the release agent and lime removed in the bag filter to the outside by rotation of the plurality of blades 93a. Particularly, the rotary valve 93 and the baffle 91 enable uniform formation of the release agent layer 92a and the lime layer 92b when the
blower 110 sucks air from the interior of the bag filter 90 to form a vacuum state therein and the release agent and the lime powder are sequentially supplied through the duct 2 to form the release agent layer 92a and the lime layer 92b in the bag 92. That is, when the release agent powder or the lime powder is sequentially supplied into the bag filter, the rotation of the rotary valve 93 at a constant speed allows the powder supplied to the lower portion of the bag filter due to the baffle 91 to be entrained by and raised along with external air intermittently supplied through a clearance C by means of the rotation of the rotary valve 93, so that the release agent powder or the lime powder can uniformly adhere to the plurality of bags 92. Reference numeral 93b designates a resin blade that adjusts a gap between a housing of the bag filter and the blade 93a and is installed to be simply exchanged when the blade 93b is worn out.
[67] Next, the condenser C will be described. The condenser C of this embodiment prevents generation of malodor and white smoke by condensing and removing moisture and impurities such as VOCs remaining in the exhaust gas that has passed through the bag filter 90. The condenser C comprises a condensation chamber 100, and a plurality of cooling pipes 101 installed in the condensation chamber 100 such that the exhaust gas passes by the cooling pipes 101. Furthermore, the condenser C comprises a second blower 106 for sucking external air and causing the external air to pass by outer peripheries of the cooling pipes and exhausting the external air together with the exhaust gas through the chimney. Although not shown in the figure, a filter for removing dust introduced from the outside is installed at an inlet pipe 102 through which the external air is introduced by the second blower 106, and an outlet pipe 105 is connected to the condensation chamber 100 such that the external air introduced into the condensation chamber 100 comes into contact with and passes by the outer peripheries of the cooling pipes 101 and is then exhausted through the chimney via the outlet pipe 105. A pipe 103 for discharging condensate is connected to a lower portion of the condensation chamber 100, and a valve 104 is installed on the pipe 103.
[68] Hereinafter, the operation of the apparatus for scrubbing exhaust gas according to this embodiment will be described.
[69] First, vacuum lower than the atmospheric pressure is formed in the condensation chamber 100 and the bag filter 90 by operating the blower 110 and the second blower 106 connected to the condensation chamber 100 to blow out exhaust gas to the outside through the chimney. Next, a predetermined amount of releasing agent powder is supplied to the duct 2 from the releasing agent hopper 95 to form the releasing agent layer 92a on the surface of the bag 92. Then, a predetermined amount of lime powder is supplied to the duct 2 from the lime hopper 96 to form the lime layer 92b on the releasing agent layer of the surface of the bag 92. At this time, the rotary valve 93 is simultaneously operated to intermittently supply external air into the bag filter through
the clearances C between the housing of the bag filter and the blades 93a so that the powder can uniformly adhere to the surface of the bag 92. In addition, there is an advantage in that the rotation of the rotary valve 93 supplies the external air so that the supplied powder can fly upward, thereby causing all the supplied powder to adhere to the bag 92 of the bag filter 90.
[70] Next, the exhaust gas introduced into the wet scrubbing chamber 10 by the operation of the blower 110 is neutralized by reacting with a solution into which an alkaline chemical sprayed from the spray nozzles 18 is dissolved, according to the reaction equations 1 to 4. The neutralized exhaust gas passes through the eliminators 11 where dust or moisture is removed therefrom, and is then exhausted through the outlet 12. Dust, neutralized salts, moisture and condensate contained in the exhaust gas, which have been removed by the eliminators 11, are collected on the bottom of the wet scrubbing chamber 10. A solution with the chemical dissolved therein is always filled in the space between the bottoms of the eliminators 11 and the bottom of the wet scrubbing chamber 10 so that the exhaust gas cannot pass through the space. Therefore, the exhaust gas is exhausted through the outlet 12 in a state where dust or moisture is always removed from the exhaust gas through the eliminators 11. The moisture, which flows to and is collected on the bottom of the wet scrubbing chamber 10, is discharged to the first reservoir 20a of the oil/water separation tank 20 through the drainpipe 19 connected to the drain hole 13. Dust and reaction salts contained in the solution are precipitated onto the bottom of the oil/water separation tank 20 while the solution is sequentially scrubbed in the oil/water separation tank 20. Sludge precipitated onto the bottom of the oil/water separation tank 20 is sent to the concentrating tank 50 through the pump 40, and the sludge is concentrated in the concentrating tank. The concentrated sludge is dehydrated in the dehydrator 70, and a cake of sludge is then discharged and disposed of. Liquid collected through dehydration in the dehydrator 70 is sent to and reused in the oil/water separation tank 20. If a value measured by the pH sensor 81 installed at the oil/water separation tank 20 is out of a predetermined range, a controller (not shown) operates the pump 83 so that the chemical stored in the tank 80 can be supplied to the oil/water separation tank 20.
[71] The exhaust gas, which has been primarily scrubbed by the wet scrubbing means A and supplied to the bag filter 90 of the dry scrubbing means B is secondly scrubbed by passing through the lime layer 92b such that residual acid gas is neutralized and dust or other impurities are adsorbed onto the lime layer or trapped in pores of the lime layer 92b. If pressure loss in the filter 92 increases due to clogging of the pores of the release agent layer and the lime layer as the bag filter 90 is continuously used for exhaust gas treatment, high-pressure air is supplied into the bag 92 to separate the release agent layer and the lime layer from the bag. Since the release agent layer is not plasterized
even though it absorbs moisture, the release agent layer is easily separated from the bag when the high-pressure air is applied in a pulse manner to the bag for the separation of the release agent layer. Therefore, the lime layer adhering to the release agent layer is also easily separated from the bag. Accordingly, when the bag is cleaned and a fresh release agent and lime are then caused to adhere to the bag as described above, the bag of the bag filter can be used semi-permanently. Since technical contents of a dedusting means for removing dust adhering to the bag 92 of the bag filter 90 are known in the art, detailed descriptions thereof will be omitted.
[72] Finally, residual impurities including fine dust and VOCs remaining in the exhaust gas, which has been secondly scrubbed in the dry scrubbing means B, are removed together with condensate while the exhaust gas passes through the condenser C, and the exhaust gas is then exhausted to the atmosphere through the chimney without generation of malodor and white smoke. Industrial Applicability
[73] According to the present invention, there is provided a hybrid-type apparatus for treating exhaust gas having a condenser, wherein exhaust gas containing hazardous substances is primarily neutralized by spraying an alkaline chemical solution to the exhaust gas, secondly passed through a simple bag filter or a bag filter to which a releasing agent layer and a chemical layer are attached to remove residual hazardous substances from the exhaust gas, and thirdly passed through the condenser to remove white smoke and malodor.
[74] In the scrubbing apparatus according to the present invention, the drain hole is formed at a position higher than the bottoms of the eliminators installed in the wet scrubbing chamber, so that moisture and dust of exhaust gas can be more efficiently removed. Furthermore, a solution containing the dust removed from the exhaust gas is scrubbed in the oil/water separation tank comprising a plurality of treatment reservoirs, thereby preventing the nozzles from being clogged. Furthermore, remaining liquid contained in sludge discharged from the oil/water separation tank is separated by the dehydrator and then reused. Thus, wastewater is not discharged, resulting in a contribution to environmental conservation.
[75] Further, in the scrubbing apparatus according to the present invention, primarily wet-scrubbed exhaust gas is subjected to secondary dry scrubbing by being supplied directly to a simple bag filter or a bag filter with a bag to which a non-plasterized releasing agent and chemical powder such as lime are sequentially attached, thereby effectively scrubbing the exhaust gas and simultaneously reducing construction and maintenance of facilities.
[76] Moreover, in the scrubbing apparatus according to the present invention, instead of
an additional combustion device for preventing generation of malodor and white smoke, an air-cooling type condenser is installed at the rear of the dry scrubbing means to avoid the generation of malodor and white smoke, thereby enabling various kinds of hazardous exhaust gas to be completely scrubbed and exhausted to the atmosphere. [77] It should be understood that the technical spirit of the present invention is not limited to the embodiments of the present invention described above and illustrated in the drawings. The scope of the present invention should be defined only by the appended claims. It is apparent to those skilled in the art that various modifications and changes can be made thereto within the technical spirit of the invention. Therefore, the modifications and changes will fall within the scope of the present invention so long as they are apparent to those skilled in the art.
Claims
[1] A hybrid- type apparatus for treating exhaust gas having a condenser, the apparatus comprising: a wet scrubbing means including a wet scrubbing chamber having an inlet through which exhaust gas is introduced, an outlet through which treated exhaust gas flows out, and a drain hole formed at a position in a side surface thereof spaced apart by a certain distance upwardly from the bottom thereof, an eliminator disposed within the wet scrubbing chamber to divide the interior of the wet scrubbing chamber into an inlet-side space and an outlet-side space and having a plurality of bent blades arranged to form a passage for the exhaust gas, and a spray nozzle for spraying liquid into the inlet-side space of the wet scrubbing chamber, the wet scrubbing chamber being disposed such that the exhaust gas introduced through the inlet horizontally flows toward the outlet, the eliminator being installed such that the bottom thereof is positioned below the drain hole; a dry scrubbing means including a duct having one end connected to the outlet of the wet scrubbing chamber, and a bag filter connected to the other end of the duct; a condenser for receiving the exhaust gas exhausted from the bag filter and condensing moisture contained in the exhaust gas to remove the moisture therefrom; and a blower connected to the condenser to blow out the exhaust gas through a chimney, whereby the exhaust gas is primarily scrubbed in the wet scrubbing means, secondly scrubbed in the dry scrubbing means, thirdly passed through the condenser to remove the moisture, and then exhausted.
[2] The apparatus according to Claim 1, wherein the wet scrubbing means further comprises: an oil/water separation tank including a plurality of reservoirs to scrub liquid received from the drain hole by sequentially passing the liquid through the plurality of reservoirs; a concentrating tank for receiving sludge precipitated in the oil/water separation tank and concentrating the sludge therein; a dehydrator for receiving the concentrated sludge from the concentrating tank, separating remaining liquid from the concentrated sludge, supplying the separated liquid to one of the reservoirs of the oil/water separation tank, and discharging a cake of sludge obtained through the separation of the remaining
liquid; a pH sensor installed at the oil/water separation tank; an alkali chemical storage tank; a chemical feed pump connected to the storage tank to feed an alkali chemical to the oil/water separation tank; and a controller for receiving a value measured by the pH sensor and supplying the chemical to the oil/water separation tank by operating the chemical feed pump if the measured value is in a predetermined range, and wherein the spray nozzle is installed to receive liquid from a final treatment reservoir of the reservoirs of the oil/water separation tank and to spray the liquid into the inlet-side space of the wet scrubbing chamber.
[3] The apparatus according to Claim 2, wherein the dry scrubbing means further includes a powder supply means connected to the duct connected to the bag filter so as to supply release agent powder and chemical powder to the bag filter through the duct, and the powder supply means supplies the release agent powder to the duct during operation of the blower to cause the release agent powder to adhere to a surface of a bag of the bag filter so as to form a release agent layer with a predetermined thickness and subsequently supplies the chemical powder to cause the chemical powder to adhere to a surface of the release agent layer so as to form a chemical layer with a predetermined thickness, whereby the exhaust gas is primarily scrubbed in the wet scrubbing means, secondly scrubbed in the dry scrubbing means, thirdly passed through the condenser to remove the moisture, and then exhausted.
[4] The apparatus according to Claim 3, wherein the bag filter includes a baffle installed between an inlet connected to the duct and the bag, and a rotary valve installed at a lower portion of the bag filter, the rotary valve includes a plurality of blades arranged at a predetermined interval along the circumference of the rotary valve, and the rotary valve is rotated at a predetermined speed to intermittently supply external air from the lower portion of the bag filter when the chemical spray means supplies the release agent powder and the chemical powder to the bag filter, so that the release agent powder and the chemical powder can uniformly adhere to the surface of the bag.
[5] The apparatus according to Claim 3 or 4, wherein the condenser comprises a condensation chamber in which a plurality of cooling pipes are installed such that the exhaust gas supplied from the bag filter passes by the cooling pipes, and a second blower installed to suck external air
and to cause the external air to pass by outer peripheries of the cooling pipes so that the external air can be exhausted together with the exhaust gas through the chimney.
[6] The apparatus according to Claim 5, wherein the plurality of blades of the eliminator are vertically disposed such that moisture or dust removed from the exhaust gas falls onto the bottom of the wet scrubbing chamber by gravity.
[7] The apparatus according to Claim 6, wherein a plurality of eliminators are provided and installed to be spaced apart from one another at a predetermined interval, and a plurality of nozzles are provided and at least one of the nozzles is installed between the eliminators.
[8] The apparatus according to Claim 7, wherein the bag filter includes a baffle installed between an inlet connected to the duct and the bag, and a rotary valve installed at a lower portion of the bag filter, the rotary valve includes a plurality of blades arranged at a predetermined interval along the circumference of the rotary valve, and the rotary valve is rotated at a predetermined speed to intermittently supply external air from the lower portion of the bag filter when the chemical spray means supplies the release agent powder and the chemical powder to the bag filter, so that the release agent powder and the chemical powder can uniformly adhere to the surface of the bag.
[9] The apparatus according to any one of Claims 6 to 8, wherein the release agent comprises 90 to 99.5 wt% of porous expansion ceramic, 0.5 to 9 wt% of binder, and 0 to 1 wt% of thickener.
[10] The apparatus according to Claim 9, wherein the porous expansion ceramic is prepared by calcining at least one rock component selected from the group consisting of obsidian, perlite, pitchstone, vermiculite, pumice and shale at a temperature range of 900 to l,600°C.
[11] The apparatus according to Claim 9, wherein the chemical powder is lime powder.
[12] The apparatus according to Claim 11, wherein the chemical powder is powder of at least one selected from activated carbon, silica gel, starch, bentonite, alumina, diatomite, zeolite, perlite, and ceramic.
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KR1020050036503A KR100639261B1 (en) | 2005-04-30 | 2005-04-30 | Hybrid-type apparatus for treating exhaust gas having a condenser |
KR10-2005-0036503 | 2005-04-30 |
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PCT/KR2005/003234 WO2006118369A1 (en) | 2005-04-30 | 2005-09-29 | Hybrid-type apparatus for treating exhaust gas having a condenser |
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WO (1) | WO2006118369A1 (en) |
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CN106925245A (en) * | 2017-04-18 | 2017-07-07 | 青岛冠宝林活性炭有限公司 | Active carbon regenerating unit and its renovation process |
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WO2018209663A1 (en) * | 2017-05-19 | 2018-11-22 | 深圳市能源环保有限公司 | Lime slurry spray system for treating flue gas of garbage incineration power plant |
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EP3669969A1 (en) * | 2018-12-18 | 2020-06-24 | Huber SE | Drying system and method for drying a wet good |
CN113457845A (en) * | 2021-08-02 | 2021-10-01 | 瑞燃(上海)环境工程技术有限公司 | Device for treating oil smoke tail gas and process method thereof |
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