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WO1992000136A1 - Reduction de dioxines et suppression simultanees d'emissions d'acides chlorhydriques d'incinerateurs de dechets solides - Google Patents

Reduction de dioxines et suppression simultanees d'emissions d'acides chlorhydriques d'incinerateurs de dechets solides Download PDF

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Publication number
WO1992000136A1
WO1992000136A1 PCT/US1991/004473 US9104473W WO9200136A1 WO 1992000136 A1 WO1992000136 A1 WO 1992000136A1 US 9104473 W US9104473 W US 9104473W WO 9200136 A1 WO9200136 A1 WO 9200136A1
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WO
WIPO (PCT)
Prior art keywords
flue gas
amount
hydrochloric acid
ammonia
present
Prior art date
Application number
PCT/US1991/004473
Other languages
English (en)
Inventor
Laszlo Takacs
Original Assignee
Occidental Chemical Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Occidental Chemical Corporation filed Critical Occidental Chemical Corporation
Publication of WO1992000136A1 publication Critical patent/WO1992000136A1/fr

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Classifications

    • 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
    • B01D53/46—Removing components of defined structure
    • B01D53/68—Halogens or halogen compounds
    • B01D53/70—Organic halogen compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Definitions

  • This invention relates to a method and apparatus for reducing the formation of dioxins in the flue gas from municipal solid waste incinerators, for removing hydrochloric acid from the flue gas, and optionally also for the removal of nitrogen oxides and sulfur oxides.
  • it relates to the injection of ammonia into the flue gas, in an amount at least sufficient to react stoichiometrically with the amount of hydrochloric acid present in the flue gas, and to the subsequent cooling of the flue gas to about 180°C or less to precipitate ammonium chloride.
  • dioxin refers to polychlorinated dibenzo-para-dioxins, (PCDD) a family of compounds consisting of two benzene rings joined by two oxygen atoms and having from 1 to 8 chlorine atoms attached to the two rings.
  • PCDD polychlorinated dibenzo-para-dioxins
  • the dioxin of most concern is 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD) .
  • furan refers to polychlorinated dibenzo-para-furans (PCDF) , which are similar to dioxin except that only a single oxygen joins the two benzene rings.
  • dioxins shall mean either dioxin or furan or both.
  • Dioxins particularly 2,3,7,8-TCDD, have been shown to be extremely carcinogenic to certain animals. As a result, there are federal, state, and local regulations that limit their
  • MSW Municipal solid waste
  • Municipal solid waste consists of household garbage and garbage from various commercial facilities that is collected by municipalities.
  • the quantity of MSW is approaching the critical point, primarily due to larger quantities of waste generated and to fewer landfill sites. While recycling and reduction of waste at its source are useful, they can eliminate only a small percentage of the total amount of waste. As a result, more and more of the waste must be burned in MSW incinerators. These MSW incinerators greatly reduce the volume of waste to a small amount of ash, but the incineration itself produces dangerous and undesirable substances.
  • these incinerators In addition to producing dioxins in the flue gas, these incinerators also produce hydrochloric acid, sulfur oxides (S0 2 and S0_) , and various nitric oxides (NO A.) , particularly nitric oxide, NO,_(_•.
  • SUBSTITUTESHEET Summary of the Invention I have discovered that the formation of dioxins in the flue gas from a MSW incinerator can be reduced while simultaneously removing the hydrochloric acid from the flue gas by injecting ammonia into the flue gas, where the amount of ammonia is at least sufficient to react stoichiometrically with the amount of hydrochloric acid present in the flue gas, and subsequently cooling the flue gas to about 180°C. Below about 180°C ammonium chloride precipitates from the flue gas, which can be separated from the flue gas and collected with other particulates.
  • the process of this invention prevents the formation of dioxins rather than permitting dioxins to form, then removing them.
  • the process of this invention is very effective and prevents the formation of about 90% of dioxins that would otherwise form in the flue gas, while removing about 70 to 90% of the hydrochloric acid in the flue gas.
  • the process has the additional advantage that the injection of ammonia can also be used to reduce the amount of sulfur dioxide in the flue gas, typically by about 70%, and the amount of nitrogen oxides in the flue gas, typically to about 40%.
  • SUBSTITUTE SHEET Figure 1 is a diagrammatic view illustrating a certain presently preferred process and apparatus according to this invention for injecting ammonia into the flue gas of a MSW incinerator.
  • Flue gas 5 typically has a composition of about 60 to about 1000 ppm hydrochloric acid, about 40 to about 400 ppm sulfur dioxide, and about 50 to about 1000 ppm nitric oxides. In the absence of treatment according to this invention, the flue gas would also typically contain about about 10 nanograms per dry cubic meter
  • ng/ 3 ng/ 3 "total" dioxins (i.e., those dioxins that have four (tetra) to eight (octa) chlorine atoms) . While I do not wish to be bound by any theory, it is believed that the dioxins form from reactions between the hydrochloric acid and/or chlorine and the trace amounts of unburned hydrocarbons that are typically present in the flue gas. Ammonia in ammonia storage tank 6 is passed through line 7 to vaporizer 8 then back to tank
  • the temperature at the point of injection is about 700 to about 1040°C.
  • the amount of ammonia injected through injection port 17 is at least sufficient to react stoichiometrically with the amount of NO present in the flue x gas.
  • Nitric oxide is believed to react with ammonia according to the following equations:
  • the flue gas passes through superheater 19 which consists of a bank of tubes which capture additional heat from the flue gas for use in generating steam.
  • the flue gas then enters dioxin suppression zone just before economizer 20 (a heat exchanger) .
  • Ammonia from distribution point 13 enters line 21, passes through regulator valve 22, through line 23, and is injected into dioxin suppression zone 20 through injector port 24.
  • the temperature of the flue gas at injector port 24 is about 230 to about 500°C.
  • the amount of ammonia injected at injector port 24 should be at least sufficient to react stoichiometrically with the amount of hydrochloric acid present in the flue gas.
  • the amount of ammonia injected at injection port 24 should not exceed the amount required to react stoichiometrically with the amount of hydrochloric acid present in the flue gas plus an additional amount equal to the amount required to react stoichiometrically with the amounts of sulfur dioxide and sulfur trioxide present in the flue gas. While the entire amount of the ammonia needed for
  • SUBSTITUTE SHEET NO and HCl control can be injected at injection port 17, it is preferable to inject ammonia for NO control at injection port 17 and ammonia for HCl control at injection port 24, as that is more effective in controlling the reduction of dioxins.
  • the hydrochloric acid is believed to react with the ammonia according to the equation HCl + NH_ > NH.C1.
  • the sulfur dioxide is believed to react with the ammonia according to the equation S0_
  • ammonium sulfite may oxidize to some extent to ammonium sulfate ((NH.)_SO.) in the presence of oxygen.
  • the ammonium chloride and ammonium sulfite/sulfate formed remain in a vapor state until the temperature of the flue gas cools below approximately 180*C.
  • the flue gas then passes into duct 25.
  • Additional ammonia can be passed from distribution point 13 through line 26, regulator valve 27, and line 28, where it can be injected into duct 25 through injection port 29.
  • the injection of additional ammonia at injection port 29 is for the purpose of fine-tuning the reduction of hydrochloric acid and sulfur oxides. That is, the quantities of hydrochloric acid and sulfur dioxide in duct 25 can be measured and, if significant quantities have escaped destruction at injection port 24, additional ammonia can be injected to reduce their concentrations.
  • the use of injection port 29 is not preferred as injection of ammonia at injection port 24 is usually adequate to control the hydrochloric acid and sulfur dioxide concentrations.
  • the flue gas can be passed through another heat exchanger, a flue gas cooler 30, which is optional and is used for the purpose of lowering the temperature of the flue gas.
  • the flue gas then passes through duct 31 to particulate controller 32.
  • the particulate controller 32 can be, for example, a scrubber, a dry electrostatic precipitator, a wet electrostatic precipitator, or a bag house.
  • the purpose of particulate controller 32 is to remove the particulates from the flue gas.
  • the particulates pass out hoppers 33 as fly ash which is deposited in landfills.
  • the ammonium chloride and ammonium sulfite/sulfate formed near injection port 24 also solidifies and is collected with the fly ash.
  • a continuous emission monitor 38 measures the concentrations of sulfur dioxide, nitric oxides, hydrochloric acid, and ammonia in the flue gas in bridge 36 and controls the amount of ammonia injected through injection ports 18, 24, and 29 by means of regulator valves 15, 22, and 27, respectively, in response to those concentrations.
  • the experimental apparatus consisted of a three inch (7.6 - cm) diameter, eight foot (2.44 m) long insulated, stainless steel pipe equipped with various sampling ports. It was attached to the boiler outlet duct, after the superheater and just before the economizer. The flue gas temperature at this point was approximately 454 ⁇ C. A jet pump was used to draw a small side-stream of flue gas from the boiler and re-inject it into the boiler. In a separate port, an S-type pitot tube was inserted into the boiler duct to help maintain gas flow through the apparatus at the same velocity as the flue gas.
  • Ammonia was injected at three points across the cross-section of the three inch (7.6 cm) pipe, two feet (0.6 ) upstream from the "dioxin reactor.” Dioxin concentrations were measured simultaneously before (Background) and after ammonia injection (after "dioxin reaction") .
  • the "background” sampling apparatus was a modified U.S. Environmental Protection Agency Method 5 sampling train. First, with no ammonia injected, the dioxin formation was simulated in the "dioxin reactor.” Next, ammonia was injected to test the suppression of dioxin formation by ammonia in the "dioxin reactor.”
  • the back half of the dioxin reactor sampling train was disconnected during the last few minutes of the experiments and the HCl sampling train, with or without the NH.Cl condenser, and the NH_ sampling train were connected to the back of the filters.
  • the HCl and the NH_ sampling trains (conforming to appropriate Environmental Protection Agency methods) were either connected to the ports in the three inch (7.6 cm) pipe (off side-stream sample) or were attached to the back of the dioxin reactor sampling train (off reactor sample) .
  • an NH.Cl condensation system preceded the HCl sampling train. Without the NH.Cl condensation system, the measurements of ammonia and HCl were used to confirm that the reaction between these two compounds indeed took place, and to establish an HCl ammonia balance.
  • NH.Cl condensation system When the NH.Cl condensation system was employed, it was connected to the back of the "dioxin reactor.” It consisted of coiled 1/4 inch (0.6 cm) I.D. polytetrafluoroethylene tubing, providing a gas residence time of approximately 0.25 seconds.
  • tests 2 and 3 were discarded due to anomalous results.
  • Tests B-2, B-4, B-5, and B-12 were to determine the background dioxins; samples were taken before the reactor to determine the dioxin concentration in the flue gas as it left the

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Treating Waste Gases (AREA)

Abstract

Procédé et appareil de réduction de la formation de dioxines dans du gaz de fumée provenant d'incinérateurs de déchets solides urbains et d'élimination d'acides chlorhydriques de gaz de fumée. On peut aussi réduire facultativement la concentration en NOx et on peut éliminer le SOx par injection de gaz ammoniac à travers des orifices d'injection (17, 24, 29). On injecte du gaz ammoniac dans les gaz de fumée en une quantité au moins suffisante pour permettre une réaction st÷chiométrique avec la quantité d'acide chlorhydrique présente dans les gaz de fumée. Si l'on veut également supprimer le NOx et le SOx, alors on injecte des quantités supplémentaires de gaz ammoniac avec ces gaz, à l'aide d'un dispositif de régulation (38). Le chlorure d'ammonium ainsi que le sulfite/sulfate d'ammonium forment un précipité à partir des gaz de fumée lorsque la température tombe au-dessous d'environ 180 °C, et on peut les collecter sur une grille mobile (2).
PCT/US1991/004473 1990-06-25 1991-06-20 Reduction de dioxines et suppression simultanees d'emissions d'acides chlorhydriques d'incinerateurs de dechets solides WO1992000136A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US54328790A 1990-06-25 1990-06-25
US543,287 1990-06-25

Publications (1)

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WO1992000136A1 true WO1992000136A1 (fr) 1992-01-09

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AU (1) AU8105691A (fr)
WO (1) WO1992000136A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0574705A1 (fr) * 1992-06-15 1993-12-22 Sumitomo Heavy Industries, Ltd Procédé pour l'élimination de dioxines
EP0866395A1 (fr) * 1997-03-21 1998-09-23 Von Roll Umwelttechnik AG Dispositif et méthode pour contrÔler la quantité introduite d'un moyen de traitement pour réduire la concentration d'azote dans des gaz d'échappement d'un processus de combustion
US5968467A (en) * 1995-09-22 1999-10-19 Kurita Water Industries, Co., Ltd. Dioxin formation preventative in incinerators and method for preventing the formation of dioxins
WO2007118554A1 (fr) * 2006-04-11 2007-10-25 Forschungszentrum Karlsruhe Gmbh Procédé et dispositif permettant de réduire les nox et les composés organiques halogénés dans les incinérateurs
CN104307295A (zh) * 2014-11-12 2015-01-28 湖南玉道环保科技有限公司 一种垃圾焚烧尾气处理方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5482366A (en) * 1977-12-13 1979-06-30 Kubota Ltd Hcl, sox and nox removing method for exhaust gas
JPS54102285A (en) * 1978-01-30 1979-08-11 Hitachi Plant Eng & Constr Co Ltd Purifying method for exhaust gas of municipal incinerator
JPS54110168A (en) * 1978-02-17 1979-08-29 Hitachi Plant Eng & Constr Co Ltd Method and equipment for cleaning exhaust gas
JPS596330A (ja) * 1982-07-02 1984-01-13 Kawasaki Steel Corp バツチ式コイル焼なまし炉における雰囲気ガス流の最適化方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5482366A (en) * 1977-12-13 1979-06-30 Kubota Ltd Hcl, sox and nox removing method for exhaust gas
JPS54102285A (en) * 1978-01-30 1979-08-11 Hitachi Plant Eng & Constr Co Ltd Purifying method for exhaust gas of municipal incinerator
JPS54110168A (en) * 1978-02-17 1979-08-29 Hitachi Plant Eng & Constr Co Ltd Method and equipment for cleaning exhaust gas
JPS596330A (ja) * 1982-07-02 1984-01-13 Kawasaki Steel Corp バツチ式コイル焼なまし炉における雰囲気ガス流の最適化方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, CA101(16): 136268e, issued 14 April 1984, MITSUBISHI HEAVY INDUSTRIES LTD., "Residual Ammonia Removal from Flue Gas Treatment"; & JP,A,59 006 330. See entire document. *
CHEMICAL ABSTRACTS, CA92(6): 46763d, issued 11 August 1979, IWAI et al., "Cleaning of Water Gas from the Municipal Waste Incineration"; & JP,A,54 102 285. See entire document. *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0574705A1 (fr) * 1992-06-15 1993-12-22 Sumitomo Heavy Industries, Ltd Procédé pour l'élimination de dioxines
US5968467A (en) * 1995-09-22 1999-10-19 Kurita Water Industries, Co., Ltd. Dioxin formation preventative in incinerators and method for preventing the formation of dioxins
EP0866395A1 (fr) * 1997-03-21 1998-09-23 Von Roll Umwelttechnik AG Dispositif et méthode pour contrÔler la quantité introduite d'un moyen de traitement pour réduire la concentration d'azote dans des gaz d'échappement d'un processus de combustion
WO2007118554A1 (fr) * 2006-04-11 2007-10-25 Forschungszentrum Karlsruhe Gmbh Procédé et dispositif permettant de réduire les nox et les composés organiques halogénés dans les incinérateurs
US8765089B2 (en) 2006-04-11 2014-07-01 Forschungszentrum Karlsruhe Gmbh Process and apparatus for reducing nitrogen oxides and halogenated organic compounds in incineration plants
CN104307295A (zh) * 2014-11-12 2015-01-28 湖南玉道环保科技有限公司 一种垃圾焚烧尾气处理方法

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Publication number Publication date
AU8105691A (en) 1992-01-23

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