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
  • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
  • F25J3/04163—Hot end purification of the feed air
  • F25J3/04169—Hot end purification of the feed air by adsorption of the impurities
• • 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
  • F25J3/04163—Hot end purification of the feed air
  • F25J3/04169—Hot end purification of the feed air by adsorption of the impurities
  • F25J3/04181—Regenerating the adsorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0407—Constructional details of adsorbing systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0407—Constructional details of adsorbing systems
  • B01D53/0446—Means for feeding or distributing gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0462—Temperature swing adsorption
• • 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
  • F25J3/04775—Air purification and pre-cooling
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2256/00—Main component in the product gas stream after treatment
  • B01D2256/10—Nitrogen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2256/00—Main component in the product gas stream after treatment
  • B01D2256/12—Oxygen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/40—Nitrogen compounds
  • B01D2257/404—Nitrogen oxides other than dinitrogen oxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/50—Carbon oxides
  • B01D2257/504—Carbon dioxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
  • B01D2257/702—Hydrocarbons
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/80—Water
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2259/00—Type of treatment
  • B01D2259/40—Further details for adsorption processes and devices
  • B01D2259/402—Further details for adsorption processes and devices using two beds
• • 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
  • F25J2205/00—Processes or apparatus using other separation and/or other processing means
  • F25J2205/60—Processes or apparatus using other separation and/or other processing means using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end
• • 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
  • F25J2210/06—Splitting of the feed stream, e.g. for treating or cooling in different ways
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

• the present invention relates to an installation for separating gases from air and to the process for separating gases from air using this installation. More precisely, it is a question of purifying the atmospheric air before separation of said air by cryogenic distillation.
• atmospheric air contains compounds which must be eliminated before its introduction into the heat exchangers of the cold box of an air separation unit, in particular water vapor (H20), carbon dioxide ( C02), nitrogen oxides and hydrocarbons.
• a TSA air purification process cycle comprises the following steps: Purification of the air at super-atmospheric pressure and at ambient temperature, optionally of the order of 5 to 10 ° C when using a means of refrigeration upstream of the unit a) Depressurization of the adsorber to atmospheric pressure,
• the air pre-treatment plants comprise two adsorbers, operating alternately, that is to say that one of the adsorbers is in the production phase while the other is in the regeneration phase.
• Additional steps to those described above can be added, such as a step of paralleling the two adsorbers, of varying duration, that is to say from a few seconds to several minutes or else a waiting step. without circulation of fluids through the adsorbent, for example at the end of the regeneration step.
• the purification unit is very generally installed after compression, that is to say at a pressure greater than 3 bar abs, frequently at a pressure greater than 4.5 bar abs. This pressure actually depends on the cryogenic cycle selected for the separation of the air.
• the cycle most used is the "double column” cycle (conventional dual column cycle) in which the air is compressed to a single pressure which corresponds, except for pressure drops, to the operating pressure of the so-called medium pressure column, that is to say, very generally between 4.5 and 6 bar abs.
• FIG. 1 As shown schematically in Figure 1 [Fig 1], such an arrangement results in large dead volumes on either side of the adsorbent volume.
• the diagrams la, b and c respectively represent cylindrical adsorbers with a vertical and horizontal axis and a radial adsorber.
• the adsorbent volumes when used in thin films are only a fraction of the total internal volume of the adsorber, typically less than 50%. This fraction tends to decrease when the size of the adsorbers is increased. Some of these dead volumes are necessary to ensure good distribution of the air and of the regeneration gas through the adsorbent volume.
• a very thorough purification is sought in the various impurities, in particular for hydrocarbons, especially for propane, and oxides.
• the drop in the adsorption pressure of MP to atmospheric pressure has a double, if not triple, negative impact.
• the quantity adsorbed is appreciably lower, this is in particular true for CO 2, traces of hydrocarbons and nitrogen oxides.
• the quantity of water to be stopped in the atmospheric air is very appreciably greater than that of the air MP.
• a large part of the water is effectively eliminated in liquid form at the outlet of the final refrigerant of the air compressor in the MP solution. This leads to a consequent increase in the volume of desiccant.
• the adsorption of this water also has the effect of heating the air circulating through the adsorbent, again reducing the adsorption capacity of CO 2 and other impurities.
• Hybrid solutions have therefore also been proposed with partial purification at atmospheric pressure followed by final purification at medium pressure.
• the final purification is small compared to a conventional solution but the fact of having to implement two units compensates for the gains that could be expected from such a reduction.
• a solution of the present invention is an air gas separation installation comprising in the direction of circulation of the air flow:
• a compression means 1 making it possible to compress the air flow to a pressure PI of between 1.15 bar abs and 2 bar abs,
• the adsorption unit comprising at least two adsorbers A and B each having a parallelepiped shaped envelope arranged horizontally and comprising: an inlet and an outlet for the air flow
• an adsorbent mass in a fixed bed also of parallelepiped shape, the faces of which are parallel to the faces of the envelope;
• the fluids circulate horizontally through the adsorbent mass.
• the latter can thus be maintained between two walls porous to gases for which the tolerances on the spacing can be very low. It is thus possible to obtain very thin and very homogeneous bed thicknesses. As already indicated, it is practically impossible to achieve this level of precision with a flat adsorbent bed having a large free surface.
• L will denote the length of the adsorber A, H its height and I its width.
• the section of the adsorbent mass also has a length L and a height H.
• the choice of the pressure PI is fundamental in the context of the invention.
• This pressure must be low enough to allow low-pressure technology for the adsorbers, that is to say in practice adsorber envelopes with flat surfaces and no longer cylindrical envelopes, but also be appreciably higher than atmospheric pressure for limit the negative effects listed above.
• a pressure of 1.5 bar abs for example makes it possible to use parallelepipedic adsorbers with possibly some reinforcements at the level of the flat surfaces. It also allows a very appreciable gain compared to a solution at atmospheric pressure.
• the partial pressures of the impurities increase by 50% and, these impurities being in the form of traces, the adsorption capacity of the adsorbents used also increases, as a first approximation by 50%.
• the amount of water that can be introduced is smaller and the corresponding temperature rise smaller.
• the purification at 1.5 bar abs remains significantly more voluminous than a purification in MP, at 3 or 4 bar abs, but also much more efficient than a purification at atmospheric pressure.
• the use of low pressure technology for the envelope can then tip the scales in favor of the solution according to the invention.
• fixed beds By fixed beds is meant here that the adsorbent, whether in the form of particles (beads, sticks, granules, platelets, etc.) or of structured adsorbent such as, for example, a monolith, is immobile in an envelope itself. even motionless. This is to exclude any solution where the adsorbent is mobile and in particular any rotary system of the wheel or absillet bar type (process in which it is the envelopes containing the adsorbent which are mobile).
• the parallelepipedal shape of the envelope of adsorber A allows dense and homogeneous filling of the adsorber without having to use a complex filling system.
• the installation according to the invention may have one or more of the characteristics below:
• the adsorbers A and B comprise an inlet and an outlet for the regeneration stream; Note that the inlet and outlet of the regeneration flow may be confused with the inlet and outlet of the air flow;
• At least one of the adsorbents of the adsorbent mass is in the form of particles
• said installation comprises between the compression means 1 and the cryogenic distillation unit 3 a single adsorption unit.
• the set of volumes comprises a first volume VI for introducing and distributing the air flow; a second volume V2 comprising the adsorbent mass; and a third volume V3 for recovering the purified air flow; the three volumes being contiguous and in fluid communication by their common faces; preferably the 3 volumes VI, V 2, and V3 are of parallelepipedal shape and are each of length L, height H and respective widths 11, 12, 13 with 11 ⁇ 1, 12 ⁇ 1, 13 ⁇ I;
• the second volume V2 comprises at least two sub-volumes comprising different adsorbents; these sub-volumes are preferably parallelepipedal in shape and have a height and a length equal to the height and length of the volume V2
• the volume VI and / or the volume V3 respectively comprise sub-volume Vll-V12 and V31-V32 separated by a perforated wall improving the distribution of fluids
• the volumes VI or VII and V3 or V32 each have at least one side permeable to fluids and the adsorber comprises fluid distribution and recovery boxes contiguous to the permeable faces; these distribution and recovery boxes are preferably in the shape of a half cylinder; they can strengthen the mechanical strength of the adsorber and limit the number of reinforcements that may be necessary; for example, the air flow can be made to enter through a distribution box and the waste gas to exit through a recovery box if this facilitates installation;
• the volume V2 or at least one of the sub-volumes of the volume V2 comprises over the entire length of its upper end a system intended to prevent potential local pollution of the purified air; This pollution can be linked to a bypass or a regeneration fault;
• the adsorption unit comprises N pairs of adsorbers with N> 1, each pair comprising an adsorber A and an adsorber B placed side by side so as to form a single parallelepiped; preferably, the adsorbers of the same pair are installed symmetrically with respect to their adjacent face.
• each pair of adsorbers comprises an adsorber A in adsorption and an adsorber B in regeneration, with all the adsorption adsorbers operating in parallel and all the regenerating adsorbers operating in parallel,
• each adsorber A or B or the pair of adsorbers A / B is installed in an ISO container or in a container with dimensions and gripping installation in accordance with ISO standards; note that preferably at least part of the structure of the container serves directly as a structure for the adsorber (s); preferably also at least part of the equipment annexed to the adsorption such as the valves and the regeneration gas heater is installed in the container;
• adsorbers A and B include external or internal thermal insulation on at least part of their faces.
• the envelope of adsorber A and / or adsorber B has a length L of between 2 and 15 meters; a height H of between 1 and 3 meters; and a width I of between 0.5 and 3 meters, preferably between 0.8 and 1.2 meters.
• the adsorber A of the installation according to the invention will be described in more detail with the aid of FIG. 2.
• this figure shows the various volumes V1, V2 and V3 as well as any sub-volumes.
• the term “parallelepipedal shape” is intended to mean that the casing of the adsorber has in practice its six flat faces and the appearance of a parallelepiped, but that it may include reinforcements, locally at least one layer of insulation. internal or external, and obviously the pipes or boxes for the introduction and withdrawal of air and regeneration gas.
• the adsorber being laid flat we call L its great length, I its width and H its height. In the context of the invention, it does not matter whether they are external or internal dimensions.
• the volume V2 can comprise a plurality of sub-volumes with each of said sub-volumes being able to contain a different adsorbent.
• Figure 2 shows a case corresponding to 2 under volume V21 and V22.
• the volume VI and / or the volume V3 respectively comprise sub-volume V11-V12 and V31-V32 separated by a perforated wall improving the distribution of fluids.
• the perforated part between the volumes Vil and V12 on the one hand and / or between the volumes V31 and V32 on the other hand makes it possible, with a low pressure drop, to significantly improve the distribution of the fluids entering and / or leaving the layers of 'adsorbent.
• the fluidic resistance of the adsorbent layers themselves then makes it possible to obtain very quickly, after one or two centimeters, the almost perfect distribution of the flow rates (at + or - 1% if necessary).
• a preferred embodiment will correspond to the following characteristic:
• At least some faces of an adsorber or of a pair of adsorbers have thermal insulation outside or inside the adsorber.
• This thermal insulation can use any of the conventional insulating materials (perlite, rock wool, expanded foam, etc.) but also devices such as an air gap or preferably a double air gap system as conventionally used in adsorbers. upstream of cryogenic air separation units. In this case, it is the fluid itself which acts as an insulator.
• conventional insulating materials perlite, rock wool, expanded foam, etc.
• devices such as an air gap or preferably a double air gap system as conventionally used in adsorbers. upstream of cryogenic air separation units. In this case, it is the fluid itself which acts as an insulator.
• the adsorber A or the pair of adsorbers A - B is installed in an ISO container or in a container with dimensions and gripping installation in accordance with ISO standards.
• the adsorber or the two adsorbers are assembled in a specific structure produced in the workshop, which may optionally use part of a standard ISO container.
• the advantage of complying with ISO standards is that it allows for greatly facilitated handling and transport. Any reinforcements allowing the mechanical resistance of the assembly to pressure will be contained in the standard dimensions of the containers.
• At least one of the walls of the container (side, bottom, top wall) can serve as a wall for the adsorber itself.
• the side walls can be integrated into the distribution volumes VI and / or V3. More generally, at least part of the structure of the container serves directly as a structure for the adsorber.
• the materials used for the adsorbers and their internals are, for example, carbon steel, stainless steel, aluminum, or materials with low thermal expansion, using INVAR.
• the present invention also relates to a process for separating gases from air from an air flow containing at least one impurity chosen from water vapor, carbon dioxide, nitrogen oxides and hydrocarbons, using an installation as defined above and comprising the following successive steps: compression 1 of the air flow to a pressure PI between 1.15 bar abs and 2 bar abs, purification of the compressed air flow, by adsorption using the TSA 2 type unit so as to eliminate at least one impurity contained in the air flow, and separation of the constituents of the air flow by cryogenic distillation using the unit (3), with all of step b) carried out at pressure PI.
• the method according to the invention may exhibit one or more of the characteristics below:
• the pressure PI is between 1.15 bar abs and 1.5 bar abs, preferably between 1.20 bar abs and 1.30 bar abs.
• the method implements an installation as defined above and in step b) the air flow is introduced into the volume VI or the sub-volume Vil and the purified air flow is withdrawn from the volume V3 or the sub -volume V32.
• this introduction and / or this withdrawal will preferably be carried out either horizontally via one or both lateral sides of the casing, or vertically via one or both horizontal faces of the casing, in other words via the top or the bottom of the envelope, or via a large face of the envelope;
• the installation used includes in its adsorption unit N pairs of adsorbers A and B with N> 1 with the adsorbers of the same pair side by side with so as to form a single parallelepiped and with each pair of adsorbers comprising an adsorber A in adsorption and an adsorber B in regeneration, the process comprises an additional step d) of regeneration of the adsorber B and in step b) in each adsorber A in adsorption the air flow is introduced into each volume VI or sub-volume Vil and the purified air flow is withdrawn from each volume V3 or sub-volume V32 and in step d) in each adsorber B in regeneration a regeneration stream is introduced into each volume V3 or sub-volume V32 and then withdrawn from each volume VI or sub-volume Vil.
• the air or regeneration flows are introduced or withdrawn from the various volumes VI, Vil, V3 and V32, preferably by their sides located in the side faces of the parallelepipedal shape of the adsorber A or B or by their sides located in the bases of the parallelepipedal shape of the adsorber A or B.
• the flows can be introduced / withdrawn theoretically by at least one of the 5 faces of the different volumes facing the external environment (the 2 side faces, the top face or bottom, or possibly the main face LxH).
• the side faces or by the base Preferably the side faces or by the base.
• the main face does not promote distribution and the interior face is not available if 2 adsorbers are placed side by side. As the adsorber is filled from the top, obstacles in the upper part will be avoided.
• the fluids are introduced or withdrawn from the volume VI -or depending on the case of the sub-volume Vil- vertically via one or both horizontal faces constituting the top or the bottom of the parallelepiped.
• the fluids are introduced or withdrawn via the large faces of the parallelepiped (of section L * H).
• the circulation of fluids through the adsorber takes place essentially in a straight line from the inlet to the outlet. This is meant to mean that in particular, there is no sudden change in direction, at approximately 90 °, of the fluid between its entry into the adsorber and its horizontal crossing of the adsorbent volume.
• the bypass can for its part have its origin in the settling of the adsorbent.
• the adsorption time used is 150 minutes, resulting in a cycle time of 5 hours given that the purification unit usually comprises 2 adsorbers, one being in production while the other is regenerating. These conventional times could be reduced here.
• the cryogenic process adopted results in having a large flow of waste gas that can be used for regeneration, which could potentially shorten the usual heating and cooling times. Furthermore, the depressurization and repressurization steps are practically unnecessary given the respective production pressures (1.3 bar abs) and regeneration (1.03 bar abs).
• Production times of 120, 90, or even 60 minutes can be envisaged with air to be purified, optionally introduced at a temperature above the 3 ° C. used in this example.
• air to be purified optionally introduced at a temperature above the 3 ° C. used in this example.
• the total volume of adsorbent is of the order of 6 m3 distributed almost half between activated alumina and type X zeolite exchanged with calcium and bar absyum, a particularly efficient adsorbent for stopping traces of hydrocarbons and oxides of nitrogen.
• the useful height of adsorbent is 2.1 m.
• An anti-pollution system is provided in the upper part, a reserve of adsorbent to compensate for the compaction and 10 pipes for filling the volumes V21 and V22 respectively with activated alumina and with zeolite. Fluids in and out are from the sides. These are boxes, themselves parallelepipedic, joined on either side of the adsorber proper.
• the input and output volumes VI and V3 are not here divided into sub-volumes.
• the widths available for each of them (0.25 m) allow direct introduction, the speed of the fluids being sufficiently low.
• the two adsorbers are disposed adjacent with a thermal insulating absrière bar between the facing surfaces.
• This absrière bar can be constituted simply by an air gap.
• a variant would consist in keeping only one common wall separating the two adsorbers and in using, on both sides, an internal insulation. This type of insulation is favored by the fact that the fluids circulating in contact with the insulation are dry (purified air, regeneration nitrogen).
• the adsorbers are made symmetrically so that the volumes V3A of the first adsorber and V3B of the second adsorber are adjacent (apart from the insulation absrière bar, if this solution is retained) in the central part.
• FIG 4 there is therefore shown the two adsorbers A and B.
• the various references correspond to their outer envelope. They are separated by a barrier 2 ′ providing thermal insulation. This barrier makes it possible to limit the heat losses of the regeneration flow and the heating of the purified air.
• a barrier 2 ′ providing thermal insulation. This barrier makes it possible to limit the heat losses of the regeneration flow and the heating of the purified air.
• it may include mechanical reinforcements in order to increase the rigidity of the large faces (L * H) of the adsorbers.
• L * H large faces
• the marks 3 ′ correspond to the volumes VIA and V1B intended for the supply of air to be purified and for the outlet of the regeneration gas.
• the walls (7 ', 8', 9 ') are permeable to gases but impermeable to the particles of adsorbent. These are grids or perforated sheets covered with a wire mesh smaller than the minimum particle diameter. He can also choose grids specially developed for this type of application of the “wedge wire screen” type, also commonly called Johnson grid after the name of a supplier.
• a rectangular metal sheet 10 'extending from one end of the adsorber to the other defines a guard volume 1 filled with adsorbent.
• the angle of the sheet with the horizontal allows the particles passing through the free space 13 'to completely fill the volume located below this sheet.
• the adsorbers are filled through the pipes 12 'which have a sealing flange at their upper end.
• FIG 5 is a longitudinal section of adsorbers A and B, adsorber B being an adsorber A in regeneration. It makes it possible to follow the progress of the different fluids. It is assumed that the adsorber A is in the production phase.
• the purified air 2 is collected in the volume V3A then enters the box 15 'before leaving the system.
• the other adsorber B is then in the regeneration phase.
• the regeneration gas 30 'enters through the box 15' of this adsorber follows the reverse path of the air and leaves via the box 14 '.
• the choice has been made here to allow the hot regeneration gas to enter through the center of the device formed by the two adsorbers. This configuration is not compulsory and, taking into account the inevitable thermal expansions, another arrangement could be retained.
• a single pipe has been shown for the inlet and outlet of the fluids in the adsorber. Depending on the layout, it may be more judicious to provide two separate pipes, one for the air, the other for the regeneration fluid.
• the filter at the outlet of adsorbers. Usually for this type of application, it will be integrated into the adsorbers.
• these filters are self-cleaning, that is to say that they are automatically unclogged at each cycle.
• the filter is placed in the box 15 '. It is preferably flat.
• an adsorber will preferably have the following characteristics:
• a length L between 2 and 15 meters, a height H between 1 and 3 meters and a width I between 0.5 and 3 meters, preferably between 0.8 and 1.5 meters.
• this adsorption unit is located upstream of a cryogenic distillation unit.
• This unit can in particular be well suited to the production of oxygen at low pressure, and in particular to oxygen between 90 and 98% purity.

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• 2019
  • 2019-02-21 FR FR1901731A patent/FR3093008B1/fr active Active
• 2020
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