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EP0317110B1 - Verfahren zur gleichzeitigen Erzeugung von elektrischer und thermischer Energie mit niedriger NOx-Produktion - Google Patents

Verfahren zur gleichzeitigen Erzeugung von elektrischer und thermischer Energie mit niedriger NOx-Produktion Download PDF

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Publication number
EP0317110B1
EP0317110B1 EP19880310217 EP88310217A EP0317110B1 EP 0317110 B1 EP0317110 B1 EP 0317110B1 EP 19880310217 EP19880310217 EP 19880310217 EP 88310217 A EP88310217 A EP 88310217A EP 0317110 B1 EP0317110 B1 EP 0317110B1
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European Patent Office
Prior art keywords
stream
fuel
oxygen
gaseous
turbine
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EP19880310217
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English (en)
French (fr)
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EP0317110A2 (de
EP0317110A3 (en
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Ronald D. Bell
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Radian Corp
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Radian Corp
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Priority claimed from US07/122,067 external-priority patent/US4811555A/en
Priority claimed from US07/252,778 external-priority patent/US4936088A/en
Priority claimed from US07/252,690 external-priority patent/US4930305A/en
Application filed by Radian Corp filed Critical Radian Corp
Publication of EP0317110A2 publication Critical patent/EP0317110A2/de
Publication of EP0317110A3 publication Critical patent/EP0317110A3/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
    • F01K23/103—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle with afterburner in exhaust boiler
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
    • F22B1/1861—Waste heat boilers with supplementary firing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
    • F23C6/04—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection
    • F23C6/042—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection with fuel supply in stages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • 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
    • 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 cogeneration and is more particularly concerned with a cogeneration process which ensures low NOx content of the evolved gases.
  • oxides of nitrogen are one of the principal contaminants emitted by combustion processes. In every combustion process, 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. Since nitric oxide (NO) continues to oxidise to nitrogen dioxide (NO2) in the air at ordinary temperatures, there is no way to predict with accuracy the amounts of each separately in vented gases at a given time. Thus, the total amount of nitric oxide (NO) plus nitrogen dioxide (NO2) in a sample is determined and referred to as "oxides of nitrogen (NOx)".
  • Cogeneration is a process which emits stack gases of undesirable NOX content.
  • Cogeneration is the simultaneous production of both useful thermal energy (usually steam) and electrical energy from one source of fuel.
  • One or more gas turbines followed by a waste heat boiler using natural gas as fuel for both the turbines and to heat the exhaust gases from the turbines represent a typical system.
  • NOX emissions generated with the combined firing cycle.
  • Cogeneration plants using conventional gas turbines and auxiliary fuel fired heat recovery boilers to produce electricity and steam are being subjected to stringent NO X emission standards requiring levels below the 150 ppm range.
  • New Source Performance Standards (NSPS) strictly limit NOX emission.
  • NPS New Source Performance Standards
  • Injection methods include injection of either water or steam into the combustion zone to lower the flame temperature and retard the formation of NOX, since the amount of NOX formed generally increases with increasing temperatures, or injection of ammonia to selectively reduce NOX.
  • 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. Combustion equipment modification affects the performance of the turbines and limits the range of operation. Moreover, cogeneration plants of this type employed for generating electric power and steam are being subjected to increasingly stringent NOX emission standards, and a statisfactory emission control system is required to minimize the undesirable emissions exhausted to the atmosphere. A selective catalytic reduction system is presently considered by some authorities to be the best available control technology for the reduction of NOX from the exhaust gas of a cogeneration plant, and as a consequence is required equipment.
  • the turbine exhaust temperature of most gas turbine cogeneration plants, at full or rated load of the gas turbine engine, is conventionally between 413°C (775°F) and 566°C (1050°F). Since the exhaust gas temperature is above the optimum temperature range of the usual selective catalytic reduction system, it is necessary to reduce the temperature of the exhaust gas stream before it passes through the system. Current practice is to provide steam superheater and/or steam generating tubes upstream to cool the gas to a preselected desired nominal temperature before it passes through the system. This imposes various operating limitations on the cogeneration plant which either seriously limit the operating range of the gas turbine engine or require an undesirable exhaust gas bypass or other mechanism for diverting a portion of the exhaust gas stream. Where supplementary firing is provided to increase steam production, the supplementary firing is conventionally carried out with an excess of air.
  • EP-A-0 047 346 a unitary compact structure is disclosed in which fuel is burned for the reduction of gases and complete high temperature and low temperature heat recovery is accomplished in the same structure.
  • the device is especially characterised in that total longitudinal flow of gases is broken up into shorter sections so that the successive sections can be changed in direction, whereby common walls can be provided between two sections and a smaller overall volumne required for the total structure.
  • US-A-4 706 612 discloses a process which comprises combusting fuel to produce a gaseous stream of combustion products, passing said gaseous stream to a turbine to generate electricity, and to produce a gaseous exhaust stream, adding fuel to said gaseous exhaust stream from the turbine and passing said gaseous exhaust stream to a NOx emission reduction unit, removing heat from said treated stream, and venting the resultant cooled stream to the atmosphere.
  • the invention provides for a process for reducing the NOx level in the exhaust gases from a cogeneration plant, and the process of the present invention is characterised in that, said additional fuel is added to said exhaust stream at exit from the turbine to provide a fuel-rich combustible gas stream; and said treatment in the NOx emission reduction unit comprises the steps of: combusting or catalytically treating said fuel-rich combustible gas stream in a reducing artmosphere to produce a heated, oxygen depleted gaseous stream, using at least a portion of the heat in said oxygen-depleted gaseous stream to convert water into steam, adding additional air to said oxygen-depleted gaseous stream to produce a stoichiometric excess of oxygen in the resultant stream relative to fuel present therein, and passing said resultant stream over a catalytic reactor containing an oxidising catalyst to produce an oxidised gaseous stream.
  • the present invention provides for a cogeneration system having reduced levels of NOx in its exhaust gases, comprising fuel supply means arranged to supply fuel at the exit from the turbine; and said NOx emission reduction unit comprises: combustion means or a catalytic bed for treating said fuel-rich combustible gas stream in a reducing atmosphere to produce a heated, oxygen-depleted gaseous stream, a boiler, connected to receive said heated, oxygen-depleted gaseous stream and having means to output a cooled, oxygen-depleted gaseous stream, for converting water into steam, air supply means for adding additional air to said cooled, oxygen-depleted gaseous stream to produce a stoichiometric excess of oxygen in the resultant stream relative to fuel present therein, and a catalytic reactor, containing an oxidising catalyst, connected to receive said resultant stream and to the heat exchanger downstream of the NOx emission reducing unit, for producing an oxidised gaseous stream from said resultant stream.
  • An advantage offered by the present invention is the ability to reduce the level of NOx in the exhaust from a cogeneration system to low levels without the use of ammonia. Furthermore, the NOx emissions are controlled without adversely affecting the operation of the turbine, including its fuel efficiency. Consequently, a cogeneration system according to the present invention is more economical and more readily controlled than prior art systems.
  • the reference numeral 10 designates a combustor or burner which receives fuel such as gas or naptha and compressed air and bums the air-fuel mixture to produce a gaseous effluent which passes into a duct 12 which directs it to a gas turbine 14 which is coupled to a generator (not shown), to produce electrical power.
  • the turbine exhaust gas leaves through a duct 16 into which are introduced further amounts of fuel, the amount depending upon the fuel-air ratio in the exhaust gas from the turbine. Since there will be ample air, only fuel is injected at this point.
  • the amount of fuel added is selected so that there will be 10 to 25% stoichiometric excess fuel relative to the available oxygen in the exhaust gas from the gas turbine.
  • the fuel added is ordinarily gas, such as natural gas.
  • the exhaust gaseous stream from the turbine is treated, i.e., has fuel added to it, to produce a fuel-rich, fuel-air mixture containing 10% to 25% excess of fuel over the oxygen stoichiometrically present.
  • the thus-treated exhaust gas from the turbine is then passed to an afterburner 18 wherein it is burned at a temperature of about 1093 to 1649°C (2000 to 3000°F).
  • a residence time of 0.5 seconds is required to ensure that the desired reduction of the oxides of nitrogen will occur.
  • a greater residence time can be employed, e.g., 1 minute or more, but serves no useful purpose.
  • the afterburner of unit 18 can be replaced by a reducing catalytic treatment.
  • the fuel-enriched exhaust gas from the turbine at about 427°C (800°F) to about 566°C (1050°F) is passed to a catalytic treatment zone 18, wherein the fuel-rich stream is passed over a reducing catalyst, e.g., platinum-rhodium in the zero-valent state supported on a carrier such as alumina, silica or a metal alloy.
  • a reducing catalyst e.g., platinum-rhodium in the zero-valent state supported on a carrier such as alumina, silica or a metal alloy.
  • 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 preferably 30,000 to 40,000 hr. ⁇ 1.
  • the heated gaseous stream passes into a duct 20 and is led to a waste-heat boiler 22 which effectively utilizes the heated gaseous stream to produce steam and simultaneously to cool the stream.
  • the gaseous effluent from the catalytic-treatment step when it is used, which is ordinarily at a temperature of 538-760°C (1000-1400°F), passes, as mentioned, to and through a waste-heat boiler wherein the effluent is cooled to a temperature of about 260-316°C (500-600°F).
  • the afterburner 18 when used and the waste-heat boiler 22 can, of course, be combined in the form of a fuel-burning boiler wherein the added fuel and the exhaust gas from the turbine are combusted to produce steam directly.
  • the boiler 22 discharges a waste effluent gas into a duct 24. Because of the addition of fuel to the duct 16 and the burning or catalytic treatment of the turbine exhaust gas in the presence of this fuel with significantly less than the stoichiometric requirement of oxygen, i.e., under reducing conditions, the exhaust gas in duct 24 from the boiler 22 contains not only combustion gases, but some unburned fuel. It 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 treating system widely used in the prior art.
  • air is added to the stream in conduit 24 and the resulting gaseous stream is passed to a gas treatment unit 26 wherein the gas stream is passed over an oxidizing catalyst.
  • the amount of air is added in an amount relative to the stream in conduit 24 such that the resulting stream will contain oxygen soichiometrically in excess of the amount needed to burn any fuel which may be present in the stream, e.g., 10% to 50% excess.
  • products at the boiler discharge temperature e.g., 260-316°C (500°-600°F) are mixed with air and passed over an oxidizing catalyst.
  • noble metal 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 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.
  • 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.
  • Data indicate that NOX levels in the parts per billion range can be realized by the combined reduction-oxidation operations of this invention.
  • the oxidized gaseous effluent from the unit 26 passes into a conduit 27 which leads an economizer or a low-pressure, waste-heat boiler, or the like, indicated at 28, and the heat content of the oxidized gaseous effluent is extracted to the maximum amount economically feasible.
  • the cooled gas at a temperature of about 149 to 204°C (300 to 400°F) is then discharged through an outlet conduit 30 into a stack 32 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.
  • effluent e.g. flue gas
  • an appropriate valve controls the recycle rate. At least a portion of the effluent is diverted into line 36 which conducts the diverted effluent to combustor 10.
  • the oxygen content of the turbine exhaust will be significantly lower, which will correspondingly lower the fuel requirement for the subsequent reducing step.
  • the quantity of effluent diverted can vary but, for best results the quantity of recycled effluent, e.g. flue gas, added to the combustor will be such as is required to produce a turbine exhaust at a temperature of 427-538°C (800-1000°F) with 1-2% O2.
  • the gas turbine 14 furnishes the total of the combustion-supporting air for the afterburner 18, if one is used, and that care is taken to maintain reducing conditions during this combustion, or during the catalytic treatment at 18, by appropriate control of the supply of fuel.
  • Another aspect of the invention is that heat recovery in a turbine cogeneration system is maximized in a higly economical manner and that NOX content is kept at a minimum without resort to elaborate equipment reconstruction, without heat loss by injecting water into the exhaust gases from the turbine, and without ammonia injection or catalytic reduction in the presence of ammonia.
  • gas treatment units can be any containers adapted for gas passage and containing an appropriate catalyst.
  • the turbine 14, for example can be of the type which produces substantially the same quantity of exhaust gas throughout the range of its operation, as, for example, a single cycle, single shaft gas turbine.
  • Minimizing the formation of oxides of nitrogen in cogeneration 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 cogeneration conditions; and greater NOX reduction efficiencies can be achieved.
  • a potentially obnoxious gas such as ammonia
  • a combustor is fed with natural gas to produce a combustible mixture which is combusted at a temperature of 2000°F, to produce a stream of combustion products which are fed to a turbine to generate electricity.
  • the exhaust stream from the turbine at a temperature of 427°C (800°F). contains about 14% oxygen.
  • Natural gas at ambient temperature is injected into this exhaust stream to give the resultant stream a fuel content such that the fuel is 10% in stoichiometric excess relative to the oxygen present.
  • the resultant stream is then combusted at a temperature of 1816°C (3300°F). and since the fuel is in excess, the combustion takes place in a reducing atmosphere.
  • Heat present in the combustion products is at least partially converted into steam by heat exchange with water, e.g., in boiler tubes, and the resulting gaseous stream, which is of course, oxygen depledted, has a temperature of 260°C (500°F).
  • water e.g., in boiler tubes
  • oxygen depledted has a temperature of 260°C (500°F).
  • air at ambient temperature in an amount such that the resultant stream has an oxygen content which is 50% stoichiometrically in excess relative to any fuel present in the oxygen-depleted stream to which the air is added.
  • the resultant oxygen-rich stream is then fed through a bed of platinum black supported on alumina with a space velocity of 50,000 hr. ⁇ 1. At this point the gaseous stream being processed has a temperature of 260°C (500°F).
  • This temperature increases across the catalyst bed to about 399°C (750°F). Heat is then extracted by appropriate heat exchange to leave a final stream to be vented having a temperature of about 177°C (350°F). and a NOX content of less than 50ppm.
  • a combustor is fed with natural gas to produce a combustible mixture which is combusted at a temperature of 427-538°C (800-1000°F). to produce a stream of combustion products which are fed to a turbine to generate electricity.
  • the exhaust stream from the turbine at a temperature of 800°F. contains about 14% oxygen.
  • Natural gas at ambient temperature is injected into this exhaust stream to give the resultant stream a fuel content such that the fuel is 10% in stoichiometric excess relative to the oxygen present.
  • the resultant stream is then passed over a platinum-rhodium catalyst ( ⁇ 1% supported on alumina) at a space velocity of 40,000 hr. ⁇ 1 and, since the fuel is in excess, the treatment takes place in a reducing atmosphere.
  • This catalytic treatment causes the temperature of the stream to rise to 1400°F.
  • Heat present in the combustion products is at least partially converted into steam by heat exchange with water, e.g., in boiler tubes, and the resulting gaseous stream, which is of course, oxygen depleted, has a temperature of 260°C (500°F).
  • the resultant stream has an oxygen content which is 25-50% stoichiometrically in excess relative to any fuel present in the oxygen depleted stream to which the air is added.
  • the resultant oxygen-rich stream is then fed through a bed of platinum (1 ⁇ % supported on alumina) with a space velocity of 50,000 hr. ⁇ 1.
  • the gaseous stream being processed has a temperature of 260°C (500°F). This temperature increases across the catalyst bed to about 399°C (750°F).
  • Heat is then extracted by appropriate heat exchange to leave a final stream to be vented having a temperature of about 177°C (350°F). and a NOX content of less than 50 ppm.
  • a combustor is fed with natural gas an combustion air to produce a combustible mixture which is combusted at a temperature of 927°C (1700°F). to produce a stream of combustion products which are fed to a turbine to generate electricity.
  • the exhaust stream from the turbine at a temperature of 427-538°C (800-1000°F). contains about 14% oxygen.
  • Natural gas at ambient temperature is injected into this exhaust stream to give the resultant stream a fuel content such that the fuel is 10% in stoichiometric excess relative to the oxygen present.
  • the resultant stream is then combusted at a temperature of 1816°C (3300°F). and, since the fuel is in excess, the combustion takes place in a reducing atmosphere.
  • Heat present in the combustion products is at least partially converted into steam by heat exchange with water, e.g., in boiler tubes, and the resulting gaseous stream, which is of course, oxygen depledted, has a temperature of 260°C (500°F).
  • water e.g., in boiler tubes
  • oxygen depledted has a temperature of 260°C (500°F).
  • air at ambient temperature in an amount such that the resultant stream has an oxygen content which is 25-50% stoichiometrically in excess relative to any fuel present in the oxygen-depleted stream to which the air is added.
  • the resultant oxygen-rich stream is then fed through a bed of platinum black ( ⁇ 1% supported on alumina) with a space velocity of 50,000 hr. ⁇ 1. At this point the gaseous stream being processed has a temperature of 260°C (500°F).
  • This temperature increases across the catalyst bed to about 399°C (750°F). Heat is then extracted by appropriate heat exchange to leave a final stream to be vented having a temperature of about 177°C (350°F). and a NOX content of less than 50 ppm.
  • a final stream to be vented having a temperature of about 177°C (350°F). and a NOX content of less than 50 ppm.
  • 60-65% of the final effluent stream is cycled to provide a ratio of 1.75:1.0 of recycled flue gas to combustion gases.
  • a combustor is fed with natural gas to produce a combustible mixture which is combusted at a temperature of 927°C (1700°F). to produce a stream of combustion products which are fed to a turbine to generate electricity.
  • the exhaust stream from the turbine at a temperature of 427°C (800°F). contains about 14% oxygen.
  • Natural gas at ambient temperature is injected into this exhaust stream to give the resultant stream a fuel content such that the fuel is 10% in stoichiometric excess relative to the oxygen present.
  • the resultant stream is then passed over platinum-rhodium ( ⁇ 1% supported on alumina) at a space velocity of 30,000 hr. ⁇ 1 and, since the fuel is in excess, the treatment takes place in a reducing atmosphere.
  • This catalytic treatment causes the temperature of the stream to rise to 760°C (1400°F).
  • Heat present in the combustion products in at least partially converted into steam by heat exchange with water, e.g., in boiler tubes, and the resulting gaseous stream, which is of course, oxygen depleted, has a temperature of 260°C (500°F).
  • To this oxygen-depleted stream is then added air at ambient temperature in an amount such that the resultant stream has an oxygen content which is 50% stoichiometrically in excess relative to any fuel present in the oxygen-depleted stream to which the air is added.
  • the resultant oxygen-rich stream is then fed through a bed of platinum black ( ⁇ 1% supported on alumina) with a space velocity of 50,000 hr. ⁇ 1.
  • the gaseous stream being processed has a temperature of 260°C (500°F). This temperature increases across the catalyst bed to about 399°C (750°F). Heat is then extracted by appropriate heat exchange to leave a final stream to be vented having a temperature of about 177°C (350°F). and a NOX content of less than 50 ppm.
  • 65% of the final effluent stream is cycled to provide a ratio of 1.75:1.0 of cycled effluent to combustion gases.

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  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
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Claims (19)

1. Verfahren, bei dem Brennstoff zur Erzeugung einer gasförmigen Strömung von Verbrennungsprodukten verbrannt wird, bei dem die gasförmige Strömung zu einer Turbine (14) zur Erzeugung von Elektrizität und zur Erzeugung einer gasförmigen Auslaßströmung (16) geführt wird, wobei der gasförmigen Auslaßströmung (16) aus der Turbine (14) Brennstoff zugesetzt wird und die gasförmige Auslaßströmung (16) zu einer NOx-Emissionsreduktionseinheit (18, 22, 26) geleitet wird, welche Wärme aus der behandelten Strömung nimmt und die sich ergebende gekühlte Strömung an die Atmosphäre ablüftet;
   dadurch gekennzeichnet,
   daß am Ausgang von der Turbine (14) der Auslaßströmung (16) zusätzlicher Brennstoff zugeführt wird, um eine brennstoffreiche, verbrennbare Gasströmung zu bilden;
   daß die Behandlung in der NOx-Emissionsreduktionseinheit (18, 22, 26) die folgenden Schritte umfaßt: Verbrennen oder katalytisches Behandeln der brennstoffreichen brennbaren Gasströmung in einer reduzierenden Atmosphäre, um eine aufgeheizte, sauerstoffverarmte gasförmige Strömung (20) zu erzeugen, ferner Verwenden wenigstens eines Teils der Hitze in der sauerstoffverarmten Strömung zur Umwandlung von Wasser in Dampf, ferner Zuführen von zusätzlicher Luft zu der sauerstoffverarmten Strömung (24) um einen stöchiometrischen Überschuß von Sauerstoff in der resultierenden Strömung zu erzeugen, und zwar bezüglich des in der resultierenden Strömung vorhandenen Brennstoffs, sowie Führen der resultierenden Strömung über einen katalytischen Reaktor (26), der einen oxidierenden Katalysator enthält, um eine oxidierte gasförmige Strömung zu erzeugen.
2. Verfahren nach Anspruch 1 oder 2, bei dem die gasförmige Auslaßströmung (16) am Ausgang aus der Turbine (14) eine Temperatur von 413 bis 566°C (775 bis 1050°F) aufweist.
3. Verfahren nach Anspruch 1 oder 2, bei dem der Brennstoff der gasförmigen Auslaßströmung (16) mit einer Menge von 10 bis 25 % in stöchiometrischem Überschuß zu dem in der resultierenden brennbaren Gasströmung vorhandenen Sauerstoff zugeführt wird.
4. Verfahren nach Anspruch 1, 2 oder 3, bei dem die brennbare Gasströmung bei einer Temperatur von 1093 bis 1649°C (2000 bis 3000°F) verbrannt wird.
5. Verfahren nach Anspruch 4, bei dem die brennbare Gasströmung während ihrer Verbrennung eine Verweilzeit von 0,5 Sekunden aufweist.
6. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die brennstoffreiche Strömung verbrannt wird.
7. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die brennstoffreiche Strömung katalytisch behandelt wird.
8. Verfahren nach Anspruch 7, bei dem die brennstoffreiche Gasströmung bei einer Temperatur von 427 bis 566°C (800 bis 1050°F) katalytisch behandelt wird.
9. Verfahren nach Anspruch 8, bei dem die Raumgeschwindigkeit der brennstoffreichen Gasströmung bei der katalytischen Behandlung etwa 30 000 bis 50 000 h ⁻¹ beträgt.
10. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die sauerstoffverarmte Strömung auf eine Temperatur von etwa 316 bis 371°C (500 bis 600°F) während der Umwandlung des Wassers in Dampf abgekühlt wird.
11. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die Raumgeschwindigkeit der resultierenden Strömung, die über den oxidierenden Katalysator geführt wird, etwa 30 000 bis 50 000 h ⁻¹ beträgt.
12. Verfahren nach einem der vorhergehenden Ansprüche, bei dem Luft der sauerstoffverarmten Strömung (20) in einer Menge zugesetzt wird, daß ein stöchiometrischer Überschuß von 10 bis 25 % des in der resultierenden Strömung vorhandenen Sauerstoffs gebildet wird.
13. Verfahren nach einem der vorhergehenden Ansprüche, bei dem das an die Atmosphäre abgelüftete gekühlte Gas (30) eine Temperatur von etwa 177 bis 260°C (350 bis 500°F) aufweist.
14. Verfahren nach einem der vorhergehenden Ansprüche, bei dem das an die Atmosphäre abgelüftete gekühlte Gas (30) einen NOx-Gehalt von weniger als 50 ppm aufweist.
15. Verfahren nach einem der vorhergehenden Ansprüche, ferner umfassend den Verfahrensschritt, daß wenigstens ein Teil der oxidierten Strömung zu dem Verfahrensschritt der Verbrennung von Brennstoff zurückgeführt wird.
16. Verfahren nach Anspruch 15, bei dem die rückgeführte Gasströmung 60 bis 65 % der oxidierten Strömung beträgt.
17. Cogenerationssystem, umfassend Verbrennungseinrichtungen (10) zum Verbrennen von Brennstoff und zum Erzeugen einer gasförmigen Strömung (12) von Verbrennungsprodukten; eine Turbine (14), die zur Aufnahme der gasförmigen Strömung (12) aus der Verbrennungseinrichtung (10), zur Erzeugung von Elektrizität und zur Erzeugung einer gasförmigen Auslaßströmung (16) angeschlossen ist; Brennstoffzufuhreinrichtungen zur Zuführung von Brennstoff an die gasförmige Auslaßströmung (16) aus der Turbine (14) zur Erzeugung einer brennstoffreichen brennbaren Gasströmung; eine NOx-Emissionsreduktionseinheit (18, 22, 26), die stromabwärts der Turbine (14) angeschlossen ist, um die gasförmige Auslaßströmung (16) und zugefügten Brennstoff zu empfangen; einen Wärmetauscher (28), der stromabwärts der NOx-Emissionsreduktionseinheit angeschlossen ist, um Wärme aus der behandelten Strömung (27) zu entfernen; und einen Abzug (32), der stromabwärts des Wärmetauschers (28) angeschlossen ist, um die resultierende gekühlte Strömung (30) an die Atmosphäre abzugeben;
   dadurch gekennzeichnet,
   daß die Brennstoffzufuhreinrichtung derart angeordnet und ausgebildet ist, daß sie Brennstoff am Ausgang der Turbine (14) liefert; und
   daß die NOx-Emissionsreduktionseinheit (18, 22, 26) umfaßt:
- weitere Verbrennungseinrichtungen (18) oder ein katalytisches Bett (18) zur Behandlung der brennstoffreichen brennbaren Gasströmung (16) in einer reduzierenden Atmosphäre, um eine erhitzte, sauerstoffverarmte gasförmige Strömung (20) zu erzeugen,
- einen Kocher (22), der zur Aufnahme der aufgeheizten, sauerstoffverarmten gasförmigen Strömung (20) angeschlossen ist und Einrichtungen zur Abgabe einer gekühlten, sauerstoffverarmten gasförmigen Strömung (24) besitzt, um Wasser in Dampf umzuwandeln,
- Luftzufuhreinrichtungen zur Zufuhr zusätzlicher Luft zu der gekühlten, sauerstoffverarmten gasförmigen Strömung (24), um einen stöchiometrischen Überschuß von Sauerstoff in der resultierenden Strömung (24) zu erzeugen, und zwar bezüglich des darin befindlichen Brennstoffs, und
- einen einen oxidierenden Katalysator enthaltenden katalytischen Reaktor (26), der zur Aufnahme der resultierenden Strömung und an den Wärmeaustauscher (28) stromabwärts der NOx-Emissionsreduktionseinheit (18, 22, 26) angeschlossen ist, um eine oxidierte gasförmige Strömung (27) aus der resultierenden Strömung (24) zu erzeugen.
18. Cogenerationssystem nach Anspruch 17, bei dem der Abzug (30) ein Kamin (30) ist.
19. Cogenerationssystem nach Anspruch 17 oder 18, ferner umfassend Gasrückführungseinrichtungen (36) zur Rückführung wenigstens eines Teils der oxidierten gasförmigen Strömung (27) zur Verbrennungseinrichtung (10).
EP19880310217 1987-11-18 1988-10-31 Verfahren zur gleichzeitigen Erzeugung von elektrischer und thermischer Energie mit niedriger NOx-Produktion Expired EP0317110B1 (de)

Applications Claiming Priority (6)

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US252778 1981-04-10
US122067 1987-11-18
US07/122,067 US4811555A (en) 1987-11-18 1987-11-18 Low NOX cogeneration process
US07/252,778 US4936088A (en) 1987-11-18 1988-10-03 Low NOX cogeneration process
US252690 1988-10-03
US07/252,690 US4930305A (en) 1987-11-18 1988-10-03 Low NOX cogeneration process

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EP0317110A3 EP0317110A3 (en) 1990-03-07
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US4951579A (en) * 1987-11-18 1990-08-28 Radian Corporation Low NOX combustion process
DE3905775A1 (de) * 1989-02-24 1990-08-30 Kat Tec Ges Fuer Katalysatorte Verfahren und vorrichtung zur reduzierung von schadstoffen eines verbrennungsverfahrens mit oxidations-wabenkatalysatoren und katalysatoren mit entschwefelungseigenschaften und abgasrueckfuehrung
AU667977B2 (en) * 1992-11-27 1996-04-18 Pilkington Glass Limited Glass furnaces
GB9224852D0 (en) * 1992-11-27 1993-01-13 Pilkington Glass Ltd Flat glass furnaces
JP3794796B2 (ja) * 1997-08-29 2006-07-12 三菱重工業株式会社 コンバインド発電プラント
GB2544552A (en) * 2015-11-20 2017-05-24 Siemens Ag A gas turbine system
WO2023004073A1 (en) * 2021-07-21 2023-01-26 Modern Electron, Inc. Combustion systems including heat modules, and associated devices and methods

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DE3072145D1 (en) * 1980-09-01 1989-04-20 Zink Co John Disposal of oxides of nitrogen and heat recovery in a single self-contained structure
JPS5844204A (ja) * 1981-09-10 1983-03-15 Toshiba Corp コンバインドサイクル発電プラント
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ES2030871T3 (es) 1992-11-16

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