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EP0317111A2 - Abfallverbrennungsverfahren mit niedriger NOx-Produktion - Google Patents

Abfallverbrennungsverfahren mit niedriger NOx-Produktion Download PDF

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Publication number
EP0317111A2
EP0317111A2 EP88310218A EP88310218A EP0317111A2 EP 0317111 A2 EP0317111 A2 EP 0317111A2 EP 88310218 A EP88310218 A EP 88310218A EP 88310218 A EP88310218 A EP 88310218A EP 0317111 A2 EP0317111 A2 EP 0317111A2
Authority
EP
European Patent Office
Prior art keywords
stream
oxygen
depleted
effluent
resultant
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
EP88310218A
Other languages
English (en)
French (fr)
Other versions
EP0317111B1 (de
EP0317111A3 (en
Inventor
Ronald D. Bell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Radian Corp
Original Assignee
Radian Corp
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
Priority claimed from US07/122,067 external-priority patent/US4811555A/en
Application filed by Radian Corp filed Critical Radian Corp
Publication of EP0317111A2 publication Critical patent/EP0317111A2/de
Publication of EP0317111A3 publication Critical patent/EP0317111A3/en
Application granted granted Critical
Publication of EP0317111B1 publication Critical patent/EP0317111B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/006—Layout of treatment plant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
    • F23G5/006—General arrangement of incineration plant, e.g. flow sheets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
    • F23G5/44—Details; Accessories
    • F23G5/46—Recuperation of heat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/20—Sulfur; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/10—Catalytic reduction devices

Definitions

  • This invention relates to ensuring low NOX content of products of combustion and is more particularly concerned with a hazardous waste incineration process which ensures low NOX content of the evolved gases.
  • oxides of nitrogen are one of the principal contaminants emitted by combustion processes.
  • the high temperatures at the burner result in the fixation of some oxides of nitrogen.
  • These compounds are found in stack gases mainly as nitric oxide (NO) with lesser amounts of nitrogen dioxide (NO2) and only traces of other oxides.
  • NO nitric oxide
  • NO2 nitrogen dioxide
  • NOX oxygen species of nitrogen
  • NOX control To meet the regulations for NOX emissions, several methods of NOX control have been employed. These can be classified as either equipment modification or injection methods. Injection methods include injection of either water or steam to lower the temperature since the amount of NOX formed generally increases with increas­ing temperatures, or injection of ammonia to selectively reduce NOX. Water or steam injection, however, adversely affects the overall fuel efficiency of process. A process involving the injection of ammonia into the products of combustion is shown, for example, in Welty, U.S. 4,164,546.
  • Equipment modifications include modifications to the burner or firebox to reduce the formation of NOX. Although these methods do reduce the level of NOX, each has its own drawbacks.
  • a selective catalytic reduction system is presently considered by some authorities to be the best available control technology for the reduction of NOX.
  • Currently available selective catalytic reduction systems used for the reduction of NOX employ ammonia injection into the exhaust gas stream for reaction with the NOX in the presence of a catalyst to produce nitrogen and water vapor.
  • Such systems typically have an efficiency of 80 - 90 percent when the gas stream is at temperature within a temperature range of approximately 600°-700° F.
  • the NOX reduction efficiency of the system will be significantly less if the temperature is outside the stated temperature range and the catalyst may be damaged at higher temperatures.
  • Applicant Bell has disclosed in Mc Gill et al 4,405,587, of which he is a co-patentee, oxides of nitrogen can be reduced by reaction in a reducing atmosphere such as disclosed in that patent at temperatures in excess of 2000° F.
  • NOX emissions An important source of NOX emissions is the incineration of hazardous wastes. Such incineration can be carried out in incinerators wherein the waste is combusted in a primary combustion zone followed by a secondary combustion zone. Excessive NOX emissions from such combustion are a serious environmental problem and various efforts to suppress them, such as the techniques referred to above, have been attempted, with varying results.
  • an object of this invention to provide an improved method involving incineration which brings about effective lowering of NOX in the incineration emissions.
  • an oxygen-rich primary combustion followed by a fuel-rich secondary combustion involving reducing gaseous conditions and providing an oxygen deficient gaseous effluent.
  • the secondary combustion effluent is used to generate steam and the effluent has SO2, HCl and ash removed from it.
  • Air is then added to the gaseous effluent to form a lean fuel-air mixture, and this mixture is passed over an oxidizing catalyst, with the resultant gas stream then passing to an economizer or low pressure waste heat boiler for substantial recovery of its remaining heat content, and the gas, now meeting NOX emission standards, is thereafter vented to the atmosphere.
  • the figure of the drawing is a diagrammatic flow sheet of a hazardous waste combustion system embodying features of the present invention.
  • the reference numeral 200 designates a hazardous waste incinerator comprising a primary combustion chamber 202 and a secondary combustion chamber 204. Waste to be incinerated is supplied through charge inlet 206, whereas fuel, e.g. gas, such as natural gas, is supplied through line 208, and combustion air is supplied through line 210.
  • the primary conbustion chamber is suitably in the form of a rotary kiln to accomodate solid hazardous waste, but liquid and gaseous waste can also be handled. When liquid waste is charged it suitably is atomized to ensure efficient combustion.
  • Primary combustion of the waste takes place in the primary combustion chamber or zone 202.
  • Combustion generally occurs at a temperature of 1500° to 2000°F. Should there by any ash and/or noncombustible materials in the waste incinerated in the primary combustion zone 202, generally characterized as "slag", it is discharged by gravity through bottom outlet 212.
  • slag ash and/or noncombustible materials in the waste incinerated in the primary combustion zone 202, generally characterized as "slag", it is discharged by gravity through bottom outlet 212.
  • combustion takes place in an oxygen-rich atmosphere, i.e., the amount of oxygen in the air supplied is in stoichiometric excess with respect to combustible materials provided by the fuel and the waste being incinerated. Consequently, the effluent gas from the primary combustion chamber or zone 202 as it enters secondary combustion chamber or zone 204 also has excess oxygen with respect to any combustible material in it.
  • additional fuel and, optionally, additional liquid or gaseous waste are added to the effluent gases from the primary zone in amounts such that combustible material in the form of waste and/or fuel is now in stoichiometric excess with respect to available oxygen, e.g., 10 to 25% excess, and combustion takes place in the secondary combustion zone 204 under reducing conditions, generally at about 2200° to 2600°F.
  • a residence time of 0.5 second is required.
  • a greater residence time can be employed, e.g., 1 second or more, but serves no useful purpose.
  • the hot effluent from the secondary combustion zone 204 of the incinerator is fed to a boiler 216 wherein heat in the effluent is used to generate steam, and the temperature of the hot effluent is reduced to about to 400° to 550°F, typically about 450°F.
  • a boiler 216 wherein heat in the effluent is used to generate steam, and the temperature of the hot effluent is reduced to about to 400° to 550°F, typically about 450°F.
  • Removal of SO2 HCl, and the like, from the gas is achieved by means of an alkaline absorbent, e.g., sodium carbonate, sodium bicarbonate, sodium hydroxide, calcium carbonate, and the like, either in dry form or as an aqueous solution or suspension, or other means, introduced through inlet 218. Removal of these corrosive substances is important not only to protect the catalyst but in order to protect the downstream equipment itself against damage.
  • the effluent gas from the incinerator may also carry along some ash and other solid particles. These solid materials are suitably separated from the gas in any convenient manner, e.g., by passing the gas through a bag house 220, the separated ash, and the like, being removed through drain line 222. At this point, the effluent gas stream is still oxygen deficient in terms of the stoichiometric relationship between its content of oxygen and combustible material, e.g., fuel. Thereupon, it is passed into conduit 224.
  • the gas is, however, low in NOX and the treatment of the gases flowing through the system has brought about a reduc­tion of any NOX formed, or a suppression of the formation of the NOX, without the use of ammonia or like treatment widely used in the prior art.
  • air is added to the stream in conduit 224 and the resulting gaseous stream is passed to a gas-treatment unit 226 wherein the gas stream is passed over an oxidizing catalyst.
  • the air is added in an amount relative to the stream in conduit 224 such that the resulting stream will contain oxygen stoichio­metrically in excess of the amount needed to burn any fuel or other combustible material which may be present in the stream, e.g., 10% to 50% excess.
  • products at approximately the boiler discharge temperature, e.g., 450°F. are mixed air and passed over an oxidizing catalyst.
  • noble metal oxidizing catalysts such as platinum or palladium, or base metal oxides, such as copper oxide, chrome oxide, or manganese oxide, or the like, may be used for this purpose.
  • the noble metal oxidizing catalysts e.g., platinum or palladium catalysts, are most suitably the noble metals deposited in the zero valent state upon a support, such as alumina, silica, kiesel-guhr, or a metal alloy, and the like.
  • the metal oxide catalysts are also most suitably the metal oxides supported on supports of this character. The making of such catalysts is well known to persons skilled in the art. Catalyst volumes will vary depending on the particular catalyst used. Ordinarily, the quantity of catalyst and the flow rate are such that the space velocity is typically in the range of 30,000 to 50,000 hr. ⁇ 1.
  • the oxidized gaseous effluent from the unit 226 passes into a conduit 227 which leads to an economizer or a low-pressure, waste heat boiler, or the like, indicated at 228, and the heat content of the oxidized gaseous effluent is extracted to the maximum amount economically feasible.
  • the boiler feed water which is first passed in indirect heat-exchange relationship through economizer 228, is heated by heat exchange with the gas and is passed via line 229 to boiler 216.
  • the cooled gas at a temperature of about 300° to 400°F is then discharged through an outlet conduit 230 into a stack 232 and vented to the atmosphere with the assurance that the vented effluent will comply with NOX emission standards. It will have a NOX content of less than 50 ppm.
  • gas treatment unit for example, can be any container adapted for gas passage and containing an oxidizing catalyst.
  • Minimizing the formation of oxides of nitrogen in combustion offers several advantages over the current state of the art. This process does not require that a potentially obnoxious gas, such as ammonia, be injected into the system; the reaction conditions do not require that a narrowly-controlled temperature be main­tained for the reduction of oxides of nitrogen to occur; the operating conditions are compatible with conventional incinera­tion conditions; and greater NOX reduction efficiencies can be achieved.
  • a potentially obnoxious gas such as ammonia
  • the primary combustion zone of an incinerator is fed with solid or liquid hazardous waste, auxiliary fuel, and air to produce a combustible mixture which is combusted at a temperature of 1500° - 2000°F. to produce a stream of combustion products.
  • the effluent stream from the primary combustion zone at a temperature of about 1500° - 2000°F. contains about 4% oxygen.
  • Auxiliary fuel or more liquid waste at ambient temperature is injected into this stream to give the resultant stream a fuel content such that the combustible content is 10% in stoichiometric excess relative to the oxygen present.
  • the resultant stream is then incinerated in the secondary incineration zone at a temperature of about 2000° - 2400°F.
  • Air at ambient temperature is then added to the stream in an amount such that the resultant stream has an oxygen content which is 10-50% stoichiometrically in excess relative to any combustible material present in the oxygen-depleted stream to which the air is added.
  • the resultant oxygen-rich stream is then fed through a bed containing a noble metal, e.g., platinum or palladium, supported on alumina, with a space velocity of 30,000 - 50,000 hr. ⁇ 1.
  • a noble metal e.g., platinum or palladium
  • the gaseous stream being processed has a temperature of about 450°F. This temperature increases across the catalyst bed to about 800°F.
  • Heat is then extracted by appropriate heat exchange to leave a final stream to be vented having a temperature of about 400°F. and a NOX content of less than 50ppm.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Incineration Of Waste (AREA)
  • Chimneys And Flues (AREA)
  • Treating Waste Gases (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
EP19880310218 1987-11-18 1988-10-31 Abfallverbrennungsverfahren mit niedriger NOx-Produktion Expired - Lifetime EP0317111B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US252681 1981-04-09
US07/122,067 US4811555A (en) 1987-11-18 1987-11-18 Low NOX cogeneration process
US122067 1987-11-18
US25268188A 1988-10-03 1988-10-03

Publications (3)

Publication Number Publication Date
EP0317111A2 true EP0317111A2 (de) 1989-05-24
EP0317111A3 EP0317111A3 (en) 1990-03-07
EP0317111B1 EP0317111B1 (de) 1993-03-03

Family

ID=26820113

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880310218 Expired - Lifetime EP0317111B1 (de) 1987-11-18 1988-10-31 Abfallverbrennungsverfahren mit niedriger NOx-Produktion

Country Status (4)

Country Link
EP (1) EP0317111B1 (de)
JP (1) JPH01200110A (de)
DE (1) DE3878840T2 (de)
ES (1) ES2038308T3 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5810901A (en) * 1992-11-27 1998-09-22 Pilkington Glass Limited Method for reducing NOx emissions from a regenerative glass furnace
US5820651A (en) * 1992-11-27 1998-10-13 Pilkington Glass Limited Method for reducing CO emissions from a regenerative glass furnace
GB2571793A (en) * 2018-03-09 2019-09-11 Edwards Ltd Abatement

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4826001B2 (ja) * 2000-05-31 2011-11-30 旭硝子株式会社 ガスの処理方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4060378A (en) * 1974-12-11 1977-11-29 Energiagazdalkodasi Intezet Method of firing and furnace therefor
GB2077135A (en) * 1980-05-27 1981-12-16 Acurex Corp Multiple stage catalytic combustion process and system
US4395223A (en) * 1978-06-09 1983-07-26 Hitachi Shipbuilding & Engineering Co., Ltd. Multi-stage combustion method for inhibiting formation of nitrogen oxides
US4405587A (en) * 1982-02-16 1983-09-20 Mcgill Incorporated Process for reduction of oxides of nitrogen
EP0277604A1 (de) * 1987-01-30 1988-08-10 Incinatrol Inc. Verbrennungssystem für in Metallbehältern enthaltenen Abfall

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4060378A (en) * 1974-12-11 1977-11-29 Energiagazdalkodasi Intezet Method of firing and furnace therefor
US4395223A (en) * 1978-06-09 1983-07-26 Hitachi Shipbuilding & Engineering Co., Ltd. Multi-stage combustion method for inhibiting formation of nitrogen oxides
GB2077135A (en) * 1980-05-27 1981-12-16 Acurex Corp Multiple stage catalytic combustion process and system
US4405587A (en) * 1982-02-16 1983-09-20 Mcgill Incorporated Process for reduction of oxides of nitrogen
EP0277604A1 (de) * 1987-01-30 1988-08-10 Incinatrol Inc. Verbrennungssystem für in Metallbehältern enthaltenen Abfall

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5810901A (en) * 1992-11-27 1998-09-22 Pilkington Glass Limited Method for reducing NOx emissions from a regenerative glass furnace
US5820651A (en) * 1992-11-27 1998-10-13 Pilkington Glass Limited Method for reducing CO emissions from a regenerative glass furnace
US5833730A (en) * 1992-11-27 1998-11-10 Pilkington Glass Limited Method for reducing NOx emissions from a regenerative glass furnace
US5837028A (en) * 1992-11-27 1998-11-17 Pilkington Glass Limited Method for reducing CO emissions from a regenerative glass furnace
US5849059A (en) * 1992-11-27 1998-12-15 Pilkington Glass Limited Method for reducing NOx emissions from a regenerative glass furnace
US5851256A (en) * 1992-11-27 1998-12-22 Pilkington Glass Limited Method for reducing NOx emissions from a regenerative glass furnace
GB2571793A (en) * 2018-03-09 2019-09-11 Edwards Ltd Abatement

Also Published As

Publication number Publication date
DE3878840D1 (de) 1993-04-08
EP0317111B1 (de) 1993-03-03
EP0317111A3 (en) 1990-03-07
ES2038308T3 (es) 1993-07-16
DE3878840T2 (de) 1993-10-07
JPH01200110A (ja) 1989-08-11

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