Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04521—Coupling of the air fractionation unit to an air gas-consuming unit, so-called integrated processes
  • F25J3/04612—Heat exchange integration with process streams, e.g. from the air gas consuming unit
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
  • F25J3/04157—Afterstage cooling and so-called "pre-cooling" of the feed air upstream the air purification unit and main heat exchange line
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04521—Coupling of the air fractionation unit to an air gas-consuming unit, so-called integrated processes
  • F25J3/04527—Integration with an oxygen consuming unit, e.g. glass facility, waste incineration or oxygen based processes in general
  • F25J3/04551—Integration with an oxygen consuming unit, e.g. glass facility, waste incineration or oxygen based processes in general for the metal production
  • F25J3/04557—Integration with an oxygen consuming unit, e.g. glass facility, waste incineration or oxygen based processes in general for the metal production for pig iron or steel making, e.g. blast furnace, Corex
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04521—Coupling of the air fractionation unit to an air gas-consuming unit, so-called integrated processes
  • F25J3/04563—Integration with a nitrogen consuming unit, e.g. for purging, inerting, cooling or heating
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04521—Coupling of the air fractionation unit to an air gas-consuming unit, so-called integrated processes
  • F25J3/04563—Integration with a nitrogen consuming unit, e.g. for purging, inerting, cooling or heating
  • F25J3/04575—Integration with a nitrogen consuming unit, e.g. for purging, inerting, cooling or heating for a gas expansion plant, e.g. dilution of the combustion gas in a gas turbine
  • F25J3/04581—Hot gas expansion of indirect heated nitrogen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04521—Coupling of the air fractionation unit to an air gas-consuming unit, so-called integrated processes
  • F25J3/04612—Heat exchange integration with process streams, e.g. from the air gas consuming unit
  • F25J3/04618—Heat exchange integration with process streams, e.g. from the air gas consuming unit for cooling an air stream fed to the air fractionation unit
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2270/00—Refrigeration techniques used
  • F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
  • F25J2270/906—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration by heat driven absorption chillers

Definitions

• the present invention relates to a method and an installation for air separation.
• it relates to a process which produces a flow enriched in nitrogen at a pressure of at least 2 bars which is expanded in a turbine.
• it relates to an integrated air separation process and installation with a combustion chamber.
• DE-A-2553700 describes an air separation device which produces a gas flow enriched in nitrogen. After a compression step, the gas flow is heated by indirect heat exchange inside a combustion chamber - before being ⁇ expanded - in a turbine. The expanded gas in the turbine is used to preheat the compressed gas to be sent to the combustion chamber.
• US-A-3950957 discloses an air separation device in which the nitrogen produced is expanded after being heated in a boiler. The remaining calories in the expanded nitrogen are transmitted to the boiler by indirect heat exchange.
• US-A-4557735 describes the case in which nitrogen is expanded to a cryogenic temperature, compressed, mixed with air and sent to a combustion chamber.
• EP-A-0959314 relates to a process for the expansion of a mixture of air and residual nitrogen, in which the mixture is sent to a combustion chamber.
• the proposed scheme corresponds to turbinating residual nitrogen at high temperature in an innovative and efficient manner.
• an air separation process in which a flow of compressed and purified air is separated in an air separation apparatus to produce a gas flow enriched in nitrogen at between 2 and 7 bars, the nitrogen-enriched gas flow is expanded in a turbine and the expanded gas flow is sent to a convection zone located downstream of a combustion chamber characterized in that the gas flow is expanded without having been mixed with a fuel flow and it is not mixed with an air flow after its expansion.
• the nitrogen-enriched gas flow is preheated by indirect heat exchange with the gases inside the combustion chamber before being expanded.
• the inlet temperature of the nitrogen into the turbine is at least 700 ° C.
• the nitrogen-enriched flow rate is preheated by indirect exchange in the combustion chamber in one stage to an intermediate temperature and then in a second stage to the inlet temperature of the turbine and the expanded gas sent to the chamber of combustion gives up calories at the gas flow to be relaxed during the first stage of preheating.
• the nitrogen enriched gas flow is compressed to a pressure between 5 and 20 bars before being expanded.
• the air is cooled after its compression by means of an absorption refrigeration unit and pressurized water intended for the refrigeration unit is heated by the gases of the combustion chamber added to the gas flow enriched in nitrogen.
• the air is purified in a purification means before being sent to the separation apparatus, the purification means is regenerated by a gas flow enriched in nitrogen and at least part of the flow having served for regeneration is sent to the expansion turbine.
• the nitrogen-enriched flow rate is withdrawn from a single column or from the medium pressure column and / or from the low pressure column from a double column or from the high pressure column and / or from the intermediate pressure column and / or of the low pressure column of a triple column.
• the nitrogen-enriched flow is mixed with a nitrogen-enriched gas from an external source before being expanded in the turbine.
• the nitrogen-enriched flow contains at least 50 mol% of nitrogen and between 0.5 and 10 mol% of oxygen. . . - . . '•
• the column from which the nitrogen-enriched flow comes from operates between substantially 2 and 7 bars.
• the nitrogen-enriched flow is not mixed with air before being expanded in the turbine.
• an air separation installation comprising: i) an air separation apparatus by cryogenic distillation ii) a combustion chamber followed by a heat recovery zone comprising a convection zone iii) an expansion turbine iv) means for sending air to the air separation device by cryogenic distillation v) means for withdrawing a nitrogen-enriched gas from the separation device air by cryogenic distillation vi) means for sending the nitrogen-enriched gas to the expansion turbine and vii) means for sending the nitrogen-enriched gas from the expansion turbine to the convection zone located downstream of the combustion chamber characterized in that it comprises neither means for mixing air with the nitrogen-enriched gas downstream of the turbine and upstream of the combustion chamber nor means for mixing fuel with the nitrogen-enriched gas before it is held e.
• the installation can include:
• a refrigeration unit in which the air is cooled after its compression, a pressurized water circuit intended for the refrigeration unit and means for heating the water circuit pressurized by the gases of the combustion chamber plus the gas flow enriched in nitrogen.
• a purification means in which the air is purified before being sent to the separation apparatus, the purification means being regenerated by a gas flow enriched in nitrogen and means for sending at least part of the flow used for regeneration at the expansion turbine.
• An air flow 1 is compressed in a compressor 3, cooled by means of a refrigeration unit 5 and purified in beds of adsorbents 7.
• the air is cooled in the main exchanger 9 before being sent to the medium pressure column of a double column.
• Rich liquid is sent from the medium pressure column to the low pressure column and an oxygen-rich gas is withdrawn from the low pressure column.
• This oxygen-rich gas can optionally be sent to an oxygen consuming unit which produces a fuel 27 for a combustion chamber 15.
• This unit can be a blast furnace, a unit for producing steel or other metals. .. -
• Impure nitrogen gas 1 containing from less than one to several molar percent oxygen, available at room temperature and moderate pressure (2 to 7 bars) at the head of the low pressure column of the double column with a flow rate of 50 000 Nm3 / h to 500,000 Nm3 / h is compressed in a compressor 13 at a pressure of the order of 10 to 20 bars, after regenerating the adsorbent bed 7.
• II contains the impurities trapped by it.
• This fluid then at a temperature of the order of 90 to 150 ° C (since there is no final coolant downstream from the compressor 13) is heated, in two stages separated A, B, in a combustion chamber 15 up to a temperature of the order of 700 to 800 ° C.
• the combustion chamber 15 is supplied with fuel 27 and compressed air 25 or another source of oxygen.
• the compressed air can come from a FD (forced draft fan).
• the combustion chamber is optionally constituted by an oven having at least one burner.
• the heated residual nitrogen is then expanded to a pressure close to atmospheric pressure in an expansion turbine 17 coupled to an electric generator and / or compression means of the air separation device.
• the expanded fluid 19, with a temperature of 350 to 450 ° C is then mixed with the fumes from the combustion chamber at a substantially identical level, intermediate between the two heating stages A, B previously mentioned so as to minimize the irreversibilities.
• the residual heat of the flue gases added with residual nitrogen is used to heat pressurized water 21 (to around 110-130 ° C) necessary for the operation of the absorption refrigeration unit 5 (lithium bromide or equivalent) intended to cool the air entering the air separation unit.
• the overall energy balance is particularly interesting and makes it possible to develop energy that is not very noble.
• This scheme makes it possible to efficiently valorize the energy contained in the residual nitrogen without having the expensive circuits necessary for the production of boiler water.
• the water vapor content in the flue gases is relatively low and would make it possible to recover energy at low temperature levels, without the risk of condensation (and therefore corrosion) in the chimney of the combustion chamber.
• At least some of the residual nitrogen, as well as the heat available in the system (compression or residual heat of the flue gases) can be used to regenerate the adsorbent beds of the air separation unit before '' be compressed, heated in the combustion chamber and sent to the turbine.
• the nitrogen to be expanded can be extracted from the column operating at the lowest pressure and / or from the column operating at the highest pressure and / or from the column operating at intermediate pressure (in the case where the apparatus for air separation would be a triple column).
• the combustion chamber can be oversized so that it can also produce steam, functioning as a boiler.
• Part of the residual nitrogen can be taken at various points so as to serve as bearing gas and / or for cooling the blades or the rotor of the nitrogen expansion turbine or of another turbine.
• Part of the residual nitrogen can be injected at the burners of the combustion chamber to control the Nox level.
• the scheme can obviously be designed without a nitrogen compressor, especially if the low pressure column operates at a pressure above 1.4 bar.
• FCC fluidized catalytic crac ing
• the regeneration gas is available at around 700 ° C. and 3 to 4 bars. This gas is generally turbinated and the calories are recovered. It is often found that the FCCs are small , and therefore the investment of the turbine is not justified economically. We could therefore propose to relax this gas at the same time after having mixed it with nitrogen.
• this or these gases can be mixed with nitrogen at the points indicated by the dotted arrows " 20,23,24,31 (before or after the first heating stage, just upstream of the turbine or upstream of the nitrogen compressor) depending on its temperature and pressure.
• the flow rate is of the same order of magnitude as that of the residual nitrogen (ie 50,000 Nm3 / h to 500,000 Nm3 / h).
• the pressure is typically from 2 to 6 bar abs.
• FCC regeneration can be improved by enriching the air.
• the oxygen intended for enrichment can come from the ASU which supplies the nitrogen.
• the pressure is typically from 2 to 10 bar abs and the flow rate from 20,000 Nm3 / h to 200,000 Nm3 / h.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Manufacturing & Machinery (AREA)
• Separation By Low-Temperature Treatments (AREA)
• Motor Or Generator Cooling System (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)
• Separation Of Gases By Adsorption (AREA)

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

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• 1999
  • 1999-12-30 FR FR9916751A patent/FR2803221B1/fr not_active Expired - Fee Related
• 2000
  • 2000-12-28 EP EP00993692A patent/EP1250185B1/de not_active Expired - Lifetime
  • 2000-12-28 JP JP2001549754A patent/JP2003519349A/ja not_active Withdrawn
  • 2000-12-28 WO PCT/FR2000/003706 patent/WO2001049394A2/fr not_active Ceased
  • 2000-12-28 DE DE60023557T patent/DE60023557T2/de not_active Expired - Fee Related
  • 2000-12-28 AT AT00993692T patent/ATE307659T1/de not_active IP Right Cessation
  • 2000-12-28 CA CA002389546A patent/CA2389546A1/fr not_active Abandoned
  • 2000-12-28 ES ES00993692T patent/ES2251422T3/es not_active Expired - Lifetime
  • 2000-12-28 AU AU28608/01A patent/AU2860801A/en not_active Abandoned
  • 2000-12-28 US US10/169,354 patent/US6776005B2/en not_active Expired - Fee Related
  • 2000-12-28 KR KR1020027006669A patent/KR100747615B1/ko not_active Expired - Fee Related

Non-Patent Citations (1)

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