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
  • F25J3/044—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 single pressure main column system only
• • 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
  • F25J3/04254—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using the cold stored in external cryogenic fluids
• • 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
  • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
  • F25J3/04812—Different modes, i.e. "runs" of operation
  • F25J3/04836—Variable air feed, i.e. "load" or product demand during specified periods, e.g. during periods with high respectively low power costs
• • 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
  • F25J2210/00—Processes characterised by the type or other details of the feed stream
  • F25J2210/42—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
  • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
  • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being 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
  • F25J2250/00—Details related to the use of reboiler-condensers
  • F25J2250/30—External or auxiliary boiler-condenser in general, e.g. without a specified fluid or one fluid is not a primary air component or an intermediate fluid
  • F25J2250/42—One fluid being 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
  • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
  • F25J2290/10—Mathematical formulae, modeling, plot or curves; Design methods
• • 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
  • F25J2290/62—Details of storing a fluid in a tank

Definitions

• the present invention relates to a method and apparatus for supplying nitrogen. It is common to provide a nitrogen customer by means of a gas generating apparatus, such as a cryogenic air distillation apparatus, as well as a storage of nitrogen which provides nitrogen gas which supplies the customer. when the cryogenic apparatus is out of order and / or fails to produce all the required flow rate.
• a gas generating apparatus such as a cryogenic air distillation apparatus
• the gas generator apparatus is operated only when it is more economical than using a gas storage (in gaseous or liquid form) to provide a customer.
• a gas generator A in particular for the units present on the site of a customer, is generally coupled to a "bulk” emergency supply means B ( liquid with evaporator or gas).
• the generator is always able to supply the customer via lines C, E.
• the means of emergency supply starts and transfers nitrogen via the lines D E.
• the generator is down, the emergency supply means takes over.
• the generator In this operating mode, the generator is running regardless of the customer's consumption. In the phases of low consumption of the customer compared to the nominal of the generator, the energy consumption and therefore the production cost are not optimal.
• FIG. 3 This operation according to the prior art is illustrated in FIG. 3.
• the customer consumes 20 Nm 3 / h of nitrogen, this flow being supplied entirely by distillation of air in a single-column, bubbled separation apparatus.
• the output of the apparatus increases accordingly to 40 and then 100 Nm 3 / h at the times 10 hours and 20 hours respectively.
• the separation device continues to produce its maximum flow rate of 100 Nm 3 / h, the remainder being supplied by nitrogen spraying stored to produce a flow rate of 50 Nm 3 / h.
• a method of supplying nitrogen by means of an apparatus for producing nitrogen gas by separation of air and by vaporization of liquid nitrogen in which: a) if the needs the customer's nitrogen gas is below a first threshold, the customer is provided with nitrogen exclusively by vaporization of liquid nitrogen b) if the customer's nitrogen gas requirements are greater than a second threshold, the second threshold being higher than the first threshold the customer is provided with nitrogen at least partially by the nitrogen generating apparatus.
• the customer's nitrogen requirements exceed a third threshold, higher than the second threshold, the customer is partially supplied by the nitrogen generator and partly by liquid nitrogen spraying;
• the customer's needs are between the second and the third threshold and the customer is provided solely by the nitrogen generator;
• the customer is provided with nitrogen only by the nitrogen generator
• At least one of the first, second and third thresholds is variable according to the price of electricity and / or the price of liquid nitrogen and / or the amount of liquid nitrogen in a storage connected to the vaporization means and / or the rate of change of the amount of liquid nitrogen in the storage;
• the nitrogen generating apparatus produces nitrogen gas with a substantially constant flow rate and a) if the customer's nitrogen gas requirements are lower than the substantially constant flow rate, the excess nitrogen gas portion is discharged to the atmosphere and the remaining nitrogen gas is sent to the customer b) if the customer's nitrogen gas requirements are greater than or equal to the substantially constant flow rate, all the nitrogen gas flow is sent to the customer
• the apparatus for producing nitrogen gas is a cryogenic air distillation apparatus and optionally liquid nitrogen is sent to the apparatus for producing nitrogen gas to participate in maintaining it in cold.
• a device for supplying nitrogen gas comprising an apparatus for producing nitrogen gas by separation of air, a liquid nitrogen vaporizer, a storage, means for supplying the liquid nitrogen, liquid nitrogen vaporizer by the storage, means for sending nitrogen gas from the production apparatus to the customer, means for sending nitrogen gas from the vaporizer to the customer and means for regulating at least one of the flow rates nitrogen gas sent to the customer according to the price of electricity and / or the price of liquid nitrogen and / or the amount of liquid nitrogen in the storage and / or the rate of change of the quantity of liquid nitrogen in the storage.
• the apparatus for producing nitrogen gas is a cryogenic air distillation apparatus.
• Figure 2 illustrates a nitrogen supply apparatus according to the invention.
• Figure 4 is a graph illustrating the mode of operation of this apparatus with the method according to the invention.
• the generator When its demand exceeds a certain value, the generator erases the "bulk” supply. This value is defined so that the cost of Generation by the generator becomes more economical than “bulk” supply. It depends on the cost of energy and the cost of bulk.
• the "bulk” completes the production of the generator to provide the customer.
• the customer consumes 20 Nm 3 / h of nitrogen, this flow being supplied entirely by vaporization of nitrogen coming from a storage (or possibly by the arrival of nitrogen gas from network).
• the customer's consumption then increases to 40 Nm 3 / h at 10 o'clock, the nitrogen vaporization stops completely, the production of the distillation apparatus consequently starts at 40 Nm 3 / h and reaches 100 Nm 3 / h after 8 pm
• the separation device continues to produce its maximum flow rate of 100 Nm 3 / h, the rest being supplied by vaporization of nitrogen stored to produce a flow rate of 50 Nm 3 / h.
• the nitrogen production by vaporization stops and the production of nitrogen by the distillation apparatus is lowered to 80 Nm 3 / h. Then to track the customer's consumption, the production level of the device is reduced to 40 Nm 3 / h. Beyond this value, the air distillation is stopped and to provide the low consumption of the customer at 20 Nm 3 / h, the vaporization of liquid nitrogen is restarted.
• the air separation apparatus can produce, for values between 40 and 100 Nm 3 / h, the exact consumption desired according to the invention.
• a complete set 6 comprises a storage of liquid nitrogen 1 and at least the cold box 9 of the cryogenic generator.
• the gas generator is constituted by a simple air separation column, inside a cold box 9, producing nitrogen gas 11 at the top of the column.
• An expander 7 placed on the pipe 3 of liquid expands the liquid intended for the vaporizer 5.
• An optional connection of liquid nitrogen 8 to the cold box 9 of the cryogenic generator at least partially ensures the maintenance of cold generator by biberonnage.
• the storage is also connected to the vaporizer 5 by the pipe 3.
• the vaporizer is connected to the customer via a pipe 18.
• liquid 3 is withdrawn from the storage 1, is expanded in the expander 7, and then vaporized (and warmed to room temperature) in the vaporization system 5.
• the cold box 9 does not does not work.
• the gas from the cold box 9 is sent into the customer network through line 11. No liquid flow from the storage is vaporized in the vaporizer 5.
• the gas is produced both by vaporization of nitrogen storage and by distillation, the two flow rates being mixed downstream of the vaporizer 5 (or possibly upstream as described in the patent application FR0752579 filed January 9, 2007).
• the gas from the cold box 9 is sent in the customer network through the pipe 11. No liquid flow from the storage is vaporized in the vaporizer 5. Between 60 and 70 hours time of Figure 4, the liquid 3 is withdrawn from the storage 1, expanded in the expander 7, and then vaporized (and warmed to room temperature) in the vaporization system 5. The cold box 9 does not work.
• the air separation apparatus produces a fixed flow with a nominal pressure of 8.3 barg (8.6 barg maxi). There is no reduced running and the air compressor of the distillation apparatus is at a fixed speed).
• the generator will be shut down if the flow actually supplied to the customer by the generator is below a threshold of flow deemed uneconomical depending on the cost of liquid nitrogen and electrical energy (for example, 20% of the nominal flow).
• This stop threshold can be parameterized via HMI.
• the discharge rate to the atmosphere is estimated using the fact that it is a function of the CV of the valve, its opening, the pressure PT, and the temperature of the gas. We then deduce the actual flow supplied by the generator to the customer, by difference of the nominal output rate of the generator and the discharge rate to the atmosphere.
• the start-up of the generator can be made necessary when the storage contains only a small amount of liquid (for example 10% of the maximum level) in the storage to increase the duration of supply to the customer (via the generator).
• the consumption of liquid nitrogen is then limited to the bottle-feeding (if there is one).

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Separation By Low-Temperature Treatments (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Family Cites Families (13)

• 2007
  • 2007-02-28 FR FR0753567A patent/FR2913104B1/fr not_active Expired - Fee Related
• 2008
  • 2008-02-18 JP JP2009551936A patent/JP2010521642A/ja active Pending
  • 2008-02-18 WO PCT/FR2008/050262 patent/WO2008113928A2/fr not_active Ceased
  • 2008-02-18 EP EP08762110A patent/EP2129983A2/de not_active Withdrawn
  • 2008-02-18 US US12/528,713 patent/US20110132035A1/en not_active Abandoned
  • 2008-02-18 CN CN200880006178XA patent/CN101711336B/zh not_active Expired - Fee Related

Non-Patent Citations (1)

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