WO2005085728A1 - Procede de separation d'air par distillation cryogenique et une installation pour la mise en oeuvre de ce procede - Google Patents
Procede de separation d'air par distillation cryogenique et une installation pour la mise en oeuvre de ce procede Download PDFInfo
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- WO2005085728A1 WO2005085728A1 PCT/FR2005/050111 FR2005050111W WO2005085728A1 WO 2005085728 A1 WO2005085728 A1 WO 2005085728A1 FR 2005050111 W FR2005050111 W FR 2005050111W WO 2005085728 A1 WO2005085728 A1 WO 2005085728A1
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- air
- exchanger
- oxygen
- pressure column
- flow
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- 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
- F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
- F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
- F25J3/04084—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of nitrogen
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- 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
- F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
- F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
- F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of oxygen
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- 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
- F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
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- 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
- F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
- F25J3/04193—Division of the main heat exchange line in consecutive sections having different functions
- F25J3/042—Division of the main heat exchange line in consecutive sections having different functions having an intermediate feed connection
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- 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
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
- F25J3/0429—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
- F25J3/04303—Lachmann expansion, i.e. expanded into oxygen producing or low pressure column
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- 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
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
- F25J3/04387—Details relating to the work expansion, e.g. process parameter etc. using liquid or hydraulic turbine expansion
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- 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
- F25J3/04406—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 using a dual pressure main column system
- F25J3/04412—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 using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
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- 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
- F25J3/04763—Start-up or control of the process; Details of the apparatus used
- F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
- F25J3/04872—Vertical layout of cold equipments within in the cold box, e.g. columns, heat exchangers etc.
- F25J3/04878—Side by side arrangement of multiple vessels in a main column system, wherein the vessels are normally mounted one upon the other or forming different sections of the same column
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- 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
- F25J3/04763—Start-up or control of the process; Details of the apparatus used
- F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
- F25J3/0489—Modularity and arrangement of parts of the air fractionation unit, in particular of the cold box, e.g. pre-fabrication, assembling and erection, dimensions, horizontal layout "plot"
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- 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
- F25J5/00—Arrangements of cold exchangers or cold accumulators in separation or liquefaction plants
- F25J5/002—Arrangements of cold exchangers or cold accumulators in separation or liquefaction plants for continuously recuperating cold, i.e. in a so-called recuperative heat exchanger
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- 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
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/20—Processes or apparatus using separation by rectification in an elevated pressure multiple column system wherein the lowest pressure column is at a pressure well above the minimum pressure needed to overcome pressure drop to reject the products to atmosphere
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- 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
- F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
- F25J2235/50—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being oxygen
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- 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
- F25J2240/00—Processes or apparatus involving steps for expanding of process streams
- F25J2240/02—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
- F25J2240/10—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream the fluid being air
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- 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
- F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
- F25J2290/12—Particular process parameters like pressure, temperature, ratios
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- 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
- F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
- F25J2290/42—Modularity, pre-fabrication of modules, assembling and erection, horizontal layout, i.e. plot plan, and vertical arrangement of parts of the cryogenic unit, e.g. of the cold box
Definitions
- the present invention relates to a process for separating air by cryogenic distillation and an installation for carrying out this process.
- the goal of an engineer who creates an air separation process is to minimize energy costs. It is well known to use a double air separation column to produce oxygen at low energy by liquefying, in particular, on the one hand to minimize the pressure at the discharge of the air compressor by reducing the losses of charge in the exchanger, reducing the temperature difference to the main vaporizer, and secondly to maximize the oxygen extraction efficiency by reducing the temperature difference in the exchanger, by choosing a number of theoretical trays of large distillation and installing a number of sections of structured packing or trays sufficient.
- the low pressure columns have four sections of structured packings or trays, including two sections between the bottom of the low pressure column and a rich liquid inlet, which is an oxygen-enriched liquid taken in the bottom of the column. medium pressure. These two sections are necessary to ensure high performance distillation in the bottom of the low pressure column. It is also thus that the medium-pressure columns have four sections of structured packings or trays, including two sections between the liquid air inlet and the lean liquid withdrawal.
- the exchanger of an air separation apparatus is normally composed of a set of exchange bodies or of several body subassemblies. A set of exchange bodies comprises an even number of exchange bodies each of which is fed with the same fluids to be cooled and the same fluids to be heated.
- an exchanger composed of two subsets of exchange bodies will comprise a first dispensing line sending air to be cooled to the first subset and a second dispensing line sending air to be cooled to the second subset.
- the purified and compressed air sent to the columns cools in an exchanger comprising a single body assembly that would normally have a volume of more than 200 m 3 , therefore with a ratio between the total air flow sent to the exchanger and the volume of the exchanger which would be about 2000 Nm 3 / h / m 3 in the case of the example described below.
- the frigories required for the distillation are frequently provided by a flow of air sent to an insufflation turbine supplying the low pressure column and / or a flow of air sent to a Claude turbine.
- the ratio between the amount of air sent to the exchanger and the flow rate sent to the insufflation turbine would normally be between 5: 1 and 15: 1 in the case of the example described below. In some cases, when energy is not expensive or free, it is beneficial to reduce equipment costs while increasing energy requirements.
- a quantity of compressed and purified air V is cooled in an exchange line to a cryogenic temperature and is sent at least in part to the medium pressure column, flow rates enriched with oxygen and nitrogen are sent from the medium pressure column to the low pressure column and flow rates enriched in nitrogen and oxygen are withdrawn from the low pressure column, the medium pressure column operating between 6 and 9 bar abs and the ratio between the total amount of air V entering the exchanger and the total volume of the exchanger being between 3 000 and 6 000 Nm 3 / h / m 3 .
- the total volume of the exchanger is about 110 m 3 with an exchanger which is composed at least by 14 exchange bodies, the maximum volume of a body of exchange being about 8 m 3 .
- the state of the art dictates two subsets of exchange bodies including a first subset comprising 8 exchanger bodies, grouped into four pairs and a second subset of 6 exchanger bodies, grouped into three pairs.
- the homogeneous distribution of flow rates between the different exchanger bodies is favorably achieved with a single set of exchange bodies, so that there is only one common collecting or collecting line for each fluid supplied to or from the bodies.
- the investment will be minimized by the installation of a exchange line composed of a single set of exchanger bodies (8 bodies) and whose volume will correspond to a ratio between the total amount of air V entering the exchanger and the total volume of the exchanger of about 7400 Nm 3 / h / m 3 .
- the increase in the ratio between the amount of total air V entering the exchanger and the total volume of the exchanger should be translated according to the state of the art by an increase in pressure losses in the exchanger for all the flows of the exchanger (residual nitrogen flow rate, air flow rates, oxygen flow rate, etc.), in particular because of the increase in the flow velocity due to the reduction of the flow section; passage.
- the pressure losses on the flow of oxygen will be not increased but will be kept constant at a limit value corresponding to a design usually acceptable on a flow of oxygen.
- Maintaining the speed on the oxygen flow by reducing the volume of the exchanger is generally only possible by keeping a constant passage section for each body of the exchanger, so a total number of passages of the exchanger on the constant oxygen flow, which leads to increase the number of oxygen passages of each body of the exchanger (since the number of bodies of the exchanger is reduced). Consequently, the pressure drops on the other flows will therefore increase more than what is obtained by the simple ratio of the number of bodies.
- the pressure drops on the oxygen flow rate will not exceed 400 mbar and the passage section on the oxygen flow rate will not exceed 20 to 25 Nm 3 / h / cm 2 .
- the passage section corresponds to either the constant section or the section at the point where the liquid oxygen vaporizes, for the case of a liquid flow.
- the oxygen flow rate comprises at least 30 mol%. oxygen, preferably at least 70 mol%. oxygen, more preferably at least 90 mol%. of oxygen and possibly in gaseous or liquid form at the inlet of the exchanger.
- An object of the present invention is to reduce the investment cost of the air separation installation and to increase its energy by reducing the size of the exchangers (thus increasing the pressure losses and the temperature differences in the air exchanger and increasing the temperature difference to the main vaporizer) and / or reducing the size of the distillation columns (minimizing the number of theoretical plates and the number of packing sections or trays)
- the quantity of air V sent to the exchanger includes all the air sent to the distillation and any air flows that are relaxed and then sent to the atmosphere.
- a structured packing section is a section of packings structured between an inlet and the adjacent fluid inlet or outlet.
- the structured packings are typically of the cross-corrugated type but may have other geometries. They can be perforated and / or partially offset.
- a process for separating air by cryogenic distillation using an apparatus comprising a medium pressure column and a low pressure column thermally connected to each other, a quantity of compressed and purified air V is cooled in an exchanger to a cryogenic temperature and is sent at least in part to the medium pressure column, flow rates enriched with oxygen and nitrogen are sent from the medium pressure column to the low pressure column and flow rates enriched in nitrogen and oxygen are withdrawn from the low pressure column characterized in that the ratio between the total amount of air entering the exchanger and the total volume of the exchanger is greater than 3 000 Nm 3 / h / m 3 and preferably between 3 000 and 12 000 Nm 3 / h / m 3 and in that the ratio between the flow rate of oxygen leaving the exchanger and the total cross section of the passages of the Exchanger reserved for this flow of oxygen is less than 30 Nm 3 / h / cm 2 , preferably 25 Nm 3 / h / cm 2 .
- the ratio between the amount of total air V entering the exchanger and the total volume of the exchanger is greater than 6,000 Nm 3 / h / m 3 and preferably between 6,500 and 12,000 Nm 3 / h / m 3
- the ratio between the total amount of air entering the exchanger V and the total volume of the heat exchanger is between 6500 and 12 000 Nm 3 / h / m 3
- the ratio of the quantity of total air V entering the exchanger and the total volume of the exchanger is between 7,000 and 12,000 Nm 3 / h / m 3
- the exchanger comprises at least one set of at most 12 exchange bodies, each body of an assembly being fed by the same fluids, originating for each fluid from a collecting or distributing line common to all the bodies of exchange of the whole.
- At least one liquid flow is withdrawn from a column, possibly pressurized, and vaporized in the exchanger or another exchanger.
- the maximum temperature difference at the cold end of the exchanger is 10 ° C .
- the maximum temperature difference at the hot end of the exchanger is 10 ° C .
- the maximum temperature difference at the beginning of the vaporization of the liquid oxygen in the exchanger is 3 ° C .
- the maximum temperature difference at the end of the vaporization of the liquid oxygen in the exchanger is 14 C
- an oxygen-enriched liquid is sent from the low pressure column to a reboiler where it partially vaporises by heat exchange with a nitrogen enriched gas from the medium pressure column, the reboiler having an ⁇ T of at least 2K
- a part of the compressed and purified air is sent to an insufflation turbine, having an inlet temperature of between -50 and -140 ° C., preferably between -100 and -130 ° C .
- a liquid air expansion turbine is supplied by all or part of a flow of liquid air at the outlet of the exchanger and / or ii) a refrigeration unit or chilled water produced by a group refrigerant (which may be the same water circuit as that used to cool the air at the inlet of the treatment) cools air out of an air booster and / or air at the lower pressure and / or Ni) an increased flow of air is sent to the blowing turbine so that the ratio between the amount of air V sent to the exchanger and the air flow D sent to the turbine insufflation is less than 10: 1.
- the purity of the oxygen is between 30 and 100 mol%, preferably between 95 and 100 mol%; the oxygen extraction yield is between 85 and 100%.
- an air separation plant for producing gases of air comprising a heat exchanger comprising a single set of exchange bodies, a single air collecting line to a first pressure and distribution means connecting the air collecting line at the first pressure to each of the exchange bodies, a single oxygen collecting line at a first pressure to be heated and distribution means connecting the oxygen collecting line to the first pressure to be heated to each exchange bodies, characterized in that the diameter of the oxygen collecting line is at least 25 cm.
- the exchanger comprises at least one set of at most 12 exchange bodies, each body of an assembly being fed with the same fluids, originating for each fluid from a collecting or distributing line common to all the exchange bodies of the whole.
- FIG. 1 is a diagram of an installation for implementing the method according to the invention and FIG. 2 is an illustration of an exchanger used in the installation of Figure 1.
- FIG. 1 is a diagram of an installation for implementing the method according to the invention
- FIG. 2 is an illustration of an exchanger used in the installation of Figure 1.
- an airflow 1 of 475,000 Nm 3 / h to 7 bar abs. from a purification unit (not shown) is divided into three.
- a first flow 3 is supercharged in the booster 5 to the pressure required to vaporize the liquid oxygen, for example.
- AIR HP high pressure air 7 is sent to the exchanger 10 but does not reach the cold end, being cooled to -160 ° C., expanded, liquefied and sent to the two columns 9 and 11, respectively medium pressure and low pressure of a double air separation column.
- a second non-pressurized flow AIR MP 13 is also sent to the exchanger 10 which it passes partially to -140 ° C before being sent to the bottom of the medium pressure column 9.
- a third flow rate of about 45,000 Nm 3 / h is sent to a booster 17, cooled in the exchanger partially expanded in an insufflation turbine 19, with an inlet temperature of -130 ° C, before to be sent to the low pressure column 11.
- the ratio between the air flow sent to the blowing turbine 19 and the amount of air sent to the exchanger is 10: 1.
- exchanger 10 are about 300 mbar for the air flow 13 at the lowest pressure and about 250 mbar for the waste nitrogen 35.
- the double column is a conventional apparatus except for its dimensions and the number of theoretical plates of the columns because the medium pressure column contains 40 and the low pressure column 45 and as regards the temperature difference for the reboiler 21 which is greater than 2.5 ⁇ C.
- liquids enriched in oxygen (rich liquid LR) and nitrogen (poor liquid LP) are sent from the medium pressure column to the low pressure column after cooling in the exchanger SR and relaxation in a valve.
- the low pressure column 11 contains three sections of structured packings, including a section I in the tank between the bottom of the column and the rich liquid inlet (which is joint with the inflated air inlet), a section II between the arrival of rich liquid and the arrival of liquid air and a section III between the arrival of liquid air and the arrival of poor liquid.
- the medium pressure column 9 contains three sections of structured packings, including a section I in tank between the bottom of the column and the liquid air inlet, a section II between the liquid air inlet and the poor liquid outlet LP and a section III between the LP low liquid outlet and the medium pressure nitrogen outlet 31. Obviously, if there is no withdrawal of liquid nitrogen or nitrogen gas, the medium pressure column only contains two sections, section III being deleted.
- the bottom reboiler 21 of the low pressure column 11 is in fact integrated with the medium pressure column 9 and is heated by a medium pressure nitrogen flow of this column 9.
- a flow of liquid oxygen 23 from the tank of the The low pressure column 11 is pumped to overcome the hydrostatic head and reaches the reboiler 21 where it partially vaporizes, a gas flow 25 being returned to the low pressure column below the exchange means I and a liquid flow 27 being sent to the pump 29 where it is pressurized to its operating pressure.
- the pumped flow 27 vaporizes in the exchanger 10.
- a flow of liquid nitrogen 31 is withdrawn at the top of the medium pressure column 9 above the section III, pumped and also vaporizes in the exchanger 10.
- the values of Liquid nitrogen and liquid oxygen pressures can be any value, as long as the exchanger 10 is designed according to the maximum pressure of the air required for vaporization.
- the invention also applies to the case in which a single liquid flow vaporizes in the exchanger 10, or no liquid withdrawn from a column vaporizes in the installation.
- the liquid flow rate (s) can vaporize against a cycle nitrogen flow rate.
- the liquid flow rate (s) may alternatively be vaporized in a dedicated heat exchanger only for vaporizing the liquid flow rate (s) against an air flow rate or a nitrogen cycle flow rate.
- the process may also produce liquid oxygen and / or liquid nitrogen and / or liquid argon as the final product (s).
- Nitrogen gas 33, 35 can be withdrawn from the medium pressure column 9 and or from the low pressure column 11. The nitrogen gas is heated in the subcooler SR.
- a flow of gaseous oxygen may be withdrawn as final product of the low pressure column 11 (not shown).
- This flow can possibly be pressurized in a compressor.
- a medium pressure nitrogen gas flow NG MP 33 and a low pressure residual nitrogen flow 35 are heated in the exchanger 10.
- the flow NR 35 can be used to regenerate the air purification system in a known manner and / or can be sent to a gas turbine.
- a method as described makes it possible to produce 99.5% molar OG HP oxygen. with a yield of more than 95%.
- This oxygen is typically used in a gasifier fueled by a fuel, such as natural gas.
- the low pressure column 11 may be next to the medium pressure column 9, as in the example or above it.
- the required frigories can be provided by using i) a liquid air expansion turbine fed by all or part of the liquid air flow HP 7 at the outlet of the exchanger 10 and / or ii) a refrigeration unit or chilled water produced by a refrigerating unit (which can come from the same water circuit as that used to cool the air at the inlet of the purification) to cool the air at the outlet of the air booster 5 and / or the air in output of the booster 17 and / or the air MP 13 and / or iii) by sending an increased flow of air to the blowing turbine 19 so that the ratio between the amount of air V sent to the exchanger and the air flow D sent to the insufflation turbine is less than 10: 1.
- blowers 5, 17 and / or the main compressor may be driven by electric motor and / or by hydraulic motor and / or by steam turbine and / or gas turbine.
- the turbine 19 may be coupled to a dedicated booster or a generator.
- the installation may also include conventional elements that are well known to those skilled in the art, such as a Claude turbine, a hydraulic turbine, a medium or low pressure nitrogen turbine, the supply of frigories by biberonnage, argon production column or columns, a mixing column for example supplied with air and oxygen from the low pressure column, a column operating at intermediate pressure, for example supplied by the rich liquid, and / or air, a low pressure column with double or triple reboiler etc.
- Figure 2 shows an exchanger 10 adapted for use in the process of Figure 1.
- the medium pressure air 13 is sent to a distributor line 113 and then to 8 lines 113A each of which feeds a body 100.
- the medium pressure air cooled is then sent to a collecting line (not shown) and then to the column. medium pressure.
- High pressure air 15 is sent to a distributor line 115 and then to two lines each of which feeds four bodies 100.
- High pressure air 7 is sent to a dispensing line 107 and then to two lines each of which feeds four bodies.
- Heated waste nitrogen is collected from the eight bodies 100 in a collecting line 135.
- Each body includes passages fed by a pumped liquid oxygen dispensing line having a diameter of at least 25 cm.
- the total cross section of all oxygen passages in the 8 bodies 100 is less than 25 Nm 3 / h / cm 2 , in the vicinity of 20 Nm 3 / h / cm 2 .
- the gaseous oxygen produced by vaporization is sent to a collecting line 127 whose diameter is at least 25 cm, preferably about 30 cm.
- Low pressure nitrogen 33 is sent to the header line 133.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Emergency Medicine (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007501326A JP2007526432A (ja) | 2004-03-02 | 2005-02-22 | 空気分離のための低温蒸留方法およびそれを実施するために使用される設備 |
EP05728114A EP1723372A1 (fr) | 2004-03-02 | 2005-02-22 | Procede de separation d air par distillation cryogenique et une installation pour la mise en oeuvre de ce procede |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR0450406 | 2004-03-02 | ||
FR0450406A FR2867262B1 (fr) | 2004-03-02 | 2004-03-02 | Procede de separation d'air par distillation cryogenique et une installation pour la mise en oeuvre de ce procede |
FR0405125 | 2004-05-12 | ||
FR0405125 | 2004-05-12 |
Publications (1)
Publication Number | Publication Date |
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WO2005085728A1 true WO2005085728A1 (fr) | 2005-09-15 |
Family
ID=34921449
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR2005/050111 WO2005085728A1 (fr) | 2004-03-02 | 2005-02-22 | Procede de separation d'air par distillation cryogenique et une installation pour la mise en oeuvre de ce procede |
Country Status (3)
Country | Link |
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EP (1) | EP1723372A1 (fr) |
JP (1) | JP2007526432A (fr) |
WO (1) | WO2005085728A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102564064A (zh) * | 2010-11-25 | 2012-07-11 | 林德股份公司 | 通过低温分离空气获得气态压力产物的方法 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5146756A (en) * | 1990-07-12 | 1992-09-15 | The Boc Group Plc | Air separation |
FR2778971A1 (fr) * | 1998-05-20 | 1999-11-26 | Air Liquide | Installation de production d'un gaz, forme d'un constituant ou d'un melange de constituants de l'air sous une haute pression |
US20010015069A1 (en) * | 2000-02-23 | 2001-08-23 | Kabushiki Kaisha Kobe Seiko Sho. | Production method for oxygen |
EP1150082A1 (fr) * | 2000-04-28 | 2001-10-31 | Linde Aktiengesellschaft | Procédé et dispositif d'échange de chaleur |
WO2003033978A2 (fr) * | 2001-10-17 | 2003-04-24 | L'air Liquide Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude | Procede de separation d'air par distillation cryogenique et une installation pour la mise en oeuvre de ce procede |
-
2005
- 2005-02-22 EP EP05728114A patent/EP1723372A1/fr not_active Withdrawn
- 2005-02-22 JP JP2007501326A patent/JP2007526432A/ja not_active Withdrawn
- 2005-02-22 WO PCT/FR2005/050111 patent/WO2005085728A1/fr not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5146756A (en) * | 1990-07-12 | 1992-09-15 | The Boc Group Plc | Air separation |
FR2778971A1 (fr) * | 1998-05-20 | 1999-11-26 | Air Liquide | Installation de production d'un gaz, forme d'un constituant ou d'un melange de constituants de l'air sous une haute pression |
US20010015069A1 (en) * | 2000-02-23 | 2001-08-23 | Kabushiki Kaisha Kobe Seiko Sho. | Production method for oxygen |
EP1150082A1 (fr) * | 2000-04-28 | 2001-10-31 | Linde Aktiengesellschaft | Procédé et dispositif d'échange de chaleur |
WO2003033978A2 (fr) * | 2001-10-17 | 2003-04-24 | L'air Liquide Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude | Procede de separation d'air par distillation cryogenique et une installation pour la mise en oeuvre de ce procede |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102564064A (zh) * | 2010-11-25 | 2012-07-11 | 林德股份公司 | 通过低温分离空气获得气态压力产物的方法 |
Also Published As
Publication number | Publication date |
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EP1723372A1 (fr) | 2006-11-22 |
JP2007526432A (ja) | 2007-09-13 |
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