Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
  • C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
  • C07C5/23—Rearrangement of carbon-to-carbon unsaturated bonds
  • C07C5/25—Migration of carbon-to-carbon double bonds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
  • C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
  • C07C45/33—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of CHx-moieties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J12/00—Chemical processes in general for reacting gaseous media with gaseous media; Apparatus specially adapted therefor
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C11/00—Aliphatic unsaturated hydrocarbons
  • C07C11/02—Alkenes
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
  • C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
  • C07C5/327—Formation of non-aromatic carbon-to-carbon double bonds only
  • C07C5/333—Catalytic processes
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
  • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
  • C07C51/215—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of saturated hydrocarbyl groups

Definitions

• the invention relates to a method and a device for producing alkenes derivatives.
• the processes for producing alkenes derivatives are generally fed with alkenes of very good purity, often greater than 95% by weight, in order to minimize the separation operations of the products downstream of the transformation process.
• This purity is most often obtained by purifying mixtures of alkanes and alkenes of lower purity, generally by distillation or liquid-liquid extraction.
• the corresponding purification units represent significant investment and operating costs, in particular because of the small difference in the physical properties (for example the volatility in the case of separation by distillation) of the hydrocarbons to be separated.
• US-B-6667409 discloses the integration of the process for producing alkenes from alkanes into the process for producing the alkenes derivatives. It discloses an alkane / alkene separation to obtain an alkenes-enriched feedstock which is fed to the alkene derivatization unit. This prior separation is expensive in energy.
• US-4532365 and FR-A-2525212 describe the dehydrogenation of an alkane to form a mixture containing the corresponding alkene, hydrogen, carbon oxides and the unreacted alkane.
• This mixture supplemented with oxygen, is sent over an oxidation catalyst to produce an alkene derivative, for example acrolein.
• the gas stream leaving the absorber is recycled to the dehydrogenation stage.
• This requires the removal of oxygen from this stream, which is obtained by reacting oxygen and hydrogen on a catalyst.
• the oxides of carbon are absorbed by a washing solution (e.g. amines or carbonates).
• US 2006/004226 A1 discloses a process for producing acrolein or acrylic acid from propane. Propane is dehydrogenated by heterogeneous catalysis, the secondary components are separated and the gaseous mixture comprising propane and propene are partially oxygenated by heterogeneous catalysis to form a stream comprising the product. This is separated into one product stream, and another stream comprising unconverted propane and excess oxygen. This stream is recycled to the dehydrogenation stage without further separation.
• US-B-6423875 also discloses a process for producing an acrolein or acrylic acid derivative from a feedstock comprising propane, and air, by oxy-dehydrogenation of propane to propane. air to form a mixture containing propylene. This mixture is then directed to a gas phase oxidation process to form a stream comprising the product. This is separated into a product stream, and another stream comprising unconverted propane and inerts. This stream is recycled to the oxy-dehydrogenation stage. It is previously freed by cryogenic distillation of nitrogen and all components having a boiling point below the boiling point of propylene. The distillation used is expensive and raises safety issues because the mixture to be distilled contains hydrocarbons and oxygen. In addition, the use of air as an oxidant limits the productivity of the overall process.
• US-5646304 discloses an oxidation of alkenes by pure oxygen, with recirculation of unconverted compounds, i.e. hydrocarbons, after separation by a PSA, TSA or a combination of both adsorption method. These processes are semi-discontinuous, which is a source of complexity in their control. They require many valves and wear equipment requiring expensive maintenance. Regeneration of the adsorbers requires an external gas and creates effluents that must be treated. The purge of the PSA / TSA process with a low PCI (low heating value) is burned by adding a high-PCI fuel such as natural gas. There are also risks of oxygen overconcentration in the presence of hydrocarbons in the adsorbers, especially during the recompression phases. If the adsorbents are activated carbons, the risks become prohibitive in terms of safety and flammability. In addition, argon tends to accumulate in the overall process.
• An object of the present invention is to overcome all or some of the disadvantages mentioned above, that is to say in particular to provide a process and a device for producing alkenes derivatives that can be fed by a load of alkenes. low purity in terms of energy consumption and productivity, without significant investments and in good safety conditions.
• the invention relates to a process for producing a stream comprising at least one alkene derivative comprising the following steps:
• Flow means a certain amount of a fluid per unit of time, the fluid can be liquid, gaseous or two-phase.
• the present invention relates mainly to gas phase flows.
• hydrocarbons is meant alkane, alkene or a mixture comprising at least one alkane and at least one alkene.
• one of the reactive streams comprises one or more alkenes and at least as many alkanes by volume, that is to say that the volume ratio of the alkanes on the alkenes is at least equal to 1.
• the alkenes in question may be in particular ethylene, propylene, isobutene.
• Alkanes are non-reactive compounds, or less reactive, in the chemical reactions involved in the conversion, and may be methane, ethane, propane, or isobutane, for example.
• the other components of this stream of alkenes can be compounds that are inert in these same reactions, such as nitrogen or argon.
• the other compounds may further include water, CO or CO 2 .
• the reaction is not with air, but with a flow comprising mainly oxygen.
• this stream is gaseous and comprises at least 90% oxygen by volume.
• gaseous ballast The non-reactional part of the flow.
• the constituents of the gaseous ballast do not participate in the chemical reactions. Their interest lies in their heat capacity (Cp), ie their ability to capture the heat released by the chemical reaction while limiting the increase in temperature.
• the gaseous ballast comprises less than 10%, or even less than 5%, by volume of a gas chosen from nitrogen, argon and their mixture.
• the large gaseous ballast constituted by said alkanes has several advantages over a nitrogen ballast.
• the conversion produces at least one converted stream comprising at least said alkene derivative to be produced.
• the alkenes derivatives can be in particular ethylene oxide, acrolein, acrylic acid, methacrolein, methacrylic acid.
• the applications can generally cover all gas phase oxidation of alkenes containing 2 to 4 carbons.
• the other components of the converted stream generally include other compounds, such as CO, CO 2 , water, nitrogen and / or argon, and hydrocarbons that have not, or not completely, reacted in the conversion unit.
• the mixture of alkanes and other stream compounds converted constitutes a thermal gas ballast having the aforementioned advantages.
• Step a) can be carried out in a multitubular bed or fluidized-bed reactor, or circulating fluidized bed, or plate reactor.
• step b) the conversion stream is separated into at least one stream comprising the alkenes derivative (s) that it is desired to produce and a residual stream comprising the said gaseous ballast and the inert compounds.
• This separation can be done by absorption of the alkenes derivatives in one or more solvents, for example water.
• solvents for example water.
• this residual stream in part or in whole, is separated in a selective permeation unit into at least a first stream mainly comprising the aforementioned inert compounds and a second stream comprising predominantly hydrocarbons.
• This last is generally recycled to be implemented in step a) and / or is used in another unit (dehydrogenation of alkanes, hydrocarbon cracker ...) and / or is simply used as a fuel (boiler furnace) ).
• the permeation unit uses one or more semi-permeable membranes having the ability to retain certain compounds and on the contrary to pass others. Depending on the purities desired, it may be necessary to use several purification stages.
• This type of membrane separation can be done by means of hollow fiber products composed of a polymer chosen from: polyimides, cellulose-type polymers, polysulfones, polyamides, polyesters, polyethers, polyether ketones polyetherimides, polyethylenes, polyacetylenes, polyethersulfones, polysiloxanes, polyvinylidene fluorides, polybenzimidazoles, polybenzoxazoles, polyacrylonitriles, polyazoaromatics and copolymers of these polymers.
• An advantage of the process according to the invention is that it can be fed with a feedstock in which the volume ratio of the alkanes on the alkenes is at least equal to 1.
• the compounds which are not alkenes form a gaseous ballast consisting mainly of alkanes.
• the gaseous ballast comprises at least 30% by volume of alkanes, preferably at least 50% by volume of alkanes.
• This feed generally comes from an alkane / alkene fractionation column, a catalytic cracker or cracker (optionally followed by a hydrogenation of diolefins), an alkane dehydrogenation unit or the recycling of gaseous ballast. .
• the alkene / alkane feed is sent directly to the conversion unit to alkenes.
• the separation of alkanes and inert gases (eg C0 2 ) by permeation after the alkene derivative production unit has the advantage of being more energy efficient than the conventional separation of alkenes and alkanes upstream of the unit. conversion to obtain a charge of high purity alkenes and a stream of alkanes.
• the process according to the invention using a charge of low purity alkenes and a permeation unit, makes it possible to produce alkenes derivatives and a flow rich in alkanes at a lower energy cost than a conventional method using a charge of high purity alkenes and not implementing a permeation step.
• the process according to the invention which comprises a step of permeation separation, allows the recovery of most of the oxygen and the elimination of the oxides of carbon and argon, while avoiding the need for additional energy-consuming unit operation.
• the permeation separation has the advantage of being continuous, of not requiring a regeneration step (external gas consumption and production of effluents to be treated), of not presenting the risks associated with a overconcentration of oxygen by adsorption processes and finally to purge argon which is considered a thermal poison because of its low specific heat and which, if it accumulated in the process, would degrade the thermal properties of the gaseous ballast .
• this makes it possible to reduce the size and therefore the cost of the upstream alkene / alkane separation process (for example a fractionation column), or even to eliminate it if the process for producing alkenes derivatives is the only process. using this charge.
• the operating costs (energy to separate the alkanes from the alkenes) of the fractionation column are also considerably reduced.
• Another advantage lies in conducting an oxidation reaction in a gaseous stream rich in alkanes which constitutes a thermal ballast. This oxidation will be done ideally thanks to a flow mainly comprising oxygen (at least 50% by volume), preferably at least 90% in order to minimize the presence of nitrogen (or other inerts) and to benefit from the advantages of a thermal ballast previously mentioned.
• the invention may include one or more of the following features:
• step a A non-zero proportion of said second stream comprising predominantly one or more hydrocarbons is implemented in step a).
• This makes it possible to increase the volume fraction of ballast in the alkenes charge converted in step a). Indeed, this charge generally comes from an alkane / alkene fractionation column, a catalytic cracker or cracker (optionally followed by a hydrogenation of diolefins) or a dehydrogenation unit of alkanes.
• the volume ratio of the alkanes to the alkenes is then generally between 1/20 and 20.
• the recycling of said second stream comprising predominantly one or more hydrocarbons in this feed makes it possible to adjust upward the volume ratio of the alkanes to the alkenes.
• the ratio by volume alkanes over alkenes must be at least equal to 1.
• said stream comprising one or more alkenes and one or more alkanes used in stage a) comprises from 2% to 20% of alkenes by volume.
• said stream comprising one or more alkenes and one or more alkanes used in step a) comprises at least 20% of alkanes.
• the process also comprises a step d) prior to the reaction step a) of a stream comprising predominantly one or more alkanes with a stream comprising predominantly oxygen to obtain at least said stream comprising one or more alkenes and one or more alkanes used in step a).
• step d A non-zero proportion of the second stream, obtained in step c), comprising predominantly one or more hydrocarbons, is reacted in step d).
• the process also comprises a step f), adjacent to and prior to step c), of catalytic oxidation of carbon monoxide, possibly present in said residual stream mainly comprising one or more hydrocarbons and one or more inert compounds, in carbon dioxide.
• Step f) may relate to all or part of said residual flow.
• the method further comprises a step g), adjacent and subsequent to step c), catalytic oxidation of carbon monoxide, optionally present in said second stream comprising predominantly one or more hydrocarbons, carbon dioxide.
• Step g) may relate to all or part of said second stream comprising predominantly one or more hydrocarbons.
• said alkenes comprise mainly, and preferably are, propylene
• said alkanes comprise mainly, and preferably are, propane and said alkene derivative is acrolein and / or acrylic acid.
• a non-zero fraction of the second stream from the membrane separation comprising predominantly hydrocarbons, typically alkanes
• “Non-zero fraction” means any fraction greater than 0% and up to 100%.
• “implementation” it means that the fraction of the flow in question participates in the reaction either as a reagent or as a passive compound, with a possible role of thermal or chemical ballast.
• the low purity alkenes to be converted may be from a process of oxy-dehydrogenation, or oxidative dehydrogenation, or from the dehydrogenation of the corresponding alkane. This allows a partial conversion of alkane to the corresponding alkene and allows to provide the alkene conversion process a rich alkane charge.
• the unconverted hydrocarbons resulting from the permeation separation can be used in the dehydrogenation unit, oxidizing or not, alkanes.
• the second stream comprising predominantly hydrocarbons, rich in alkanes will rather be sent directly to the reaction of conversion of alkenes in step a), or to other processes (cracking, oven, etc.) in order to to free from any subsequent purification after the permeation separation to avoid any contamination or parasitic reactions in the process of oxidative or non-oxidative dehydrogenation of the alkanes.
• the oxidation of the CO object of steps f) and g) can also be performed in parallel with the membrane separation.
• the separation is the next turn. This allows, in this case, to minimize the size of the CO converter.
• the invention also relates to a plant for producing a stream comprising at least one alkene derivative, said plant comprising:
• a flux source comprising from 2% to 20% by volume of one or more alkenes fluidly connected to said conversion unit;
• a flow source comprising mainly oxygen fluidly connected to said conversion unit
• a permeation separation unit fluidly connected to an outlet of said separator.
• connection means that there is connection by a system of pipes capable of transporting a flow of material.
• This connection system may include valves, intermediate storages, bypasses, heat exchangers, compressors, but not chemical reactors.
• the invention may include one or more of the following features: it comprises a fluid connection between an outlet of said permeation separation unit and said conversion unit or said flow source comprising mainly one or more alkenes.
• said flux source comprising from 2% to 20% by volume of one or more alkenes comprises a reactor:
• oxy-dehydrogenation fluidly connected to a source of a stream comprising predominantly one or more alkanes and a flow source comprising predominantly oxygen;
• dehydrogenation fluidly connected to a source of a stream comprising predominantly one or more alkanes.
• the installation comprises recycling means placed between an outlet of said permeation separation unit and said oxy-dehydrogenation or dehydrogenation reactor, or said source of a flow comprising predominantly one or more alkanes.
• the installation comprises a catalytic conversion unit of carbon monoxide to carbon dioxide fluidly connected to said separator and to said permeation separation unit.
• the installation comprises a catalytic conversion unit of carbon monoxide to carbon dioxide fluidly connected to an outlet of said permeation separation unit.
• the possible recycling upstream of the oxy-dehydrogenation or dehydrogenation reactor can be done in the source of alkanes or in the flow that leaves (between the source and the oxidative dehydrogenation reactor) or even directly in the reactor of oxidative dehydrogenation.
• FIG. 1 represents a schematic and partial view illustrating an exemplary device according to the invention.
• It provides a filler 23 which, mixed with a recycled stream, forms a stream 1 injected into a unit 2 for producing acrylic acid by oxidation of propylene with 99% pure oxygen by volume.
• a flow 3 comprising acrylic acid.
• This stream 3 is separated in a separator 4 into a stream 5 of acrylic acid and a stream mainly comprising propane and C0 2 .
• This flow is directed partially (flow 6 to a separation unit 7 and flow 24 which by-passes the separation unit) or totally (flow 6) to a separation unit 7 by permeation.
• condensation can separate water (mainly) from other constituents (stream 27).
• the separation unit 7 comprises polyetherimide hollow fiber-based membranes, sufficient in number to purge the amount of C0 2 produced in the unit 2 and the units 21 and 22 in the stream 8.
• the stream 6 feeds at a high temperature. pressure (for example 10 bar) the unit 7 containing the semi-permeable membranes.
• the compounds present in the stream 6 will solubilize and diffuse through the polymer fibers of the unit 7 at different speeds so that preferentially the fast compounds will cross the fiber and end up in the low pressure side of the membrane, called flow of permeate and constituting the purge.
• the slow compounds will remain on the high pressure side and constitute the stream 9.
• the stream 8 comprises C0 2 (the main inert compound to be purged from the stream 6) and the stream 9 comprises propane.
• a non-zero fraction 10 is mixed with the stream 23 to form the stream 1 sent to the conversion unit 2.
• a non-zero fraction 11 of the stream 9 is sent to one or more user units and / or is simply used as a fuel.
• the reactor 15 performs an oxy-dehydrogenation of a stream 14 comprising propane from a source 16. This oxy-dehydrogenation requires a stream 17 comprising mainly oxygen from a source 20. A non-zero fraction 18 of the stream 9 is injected into the stream 14 or directly into the oxy-dehydrogenation reactor.
• Stream 23 comprises propylene and propane.
• the assembly 15, 16, 20 is part of a source 12 supplying the stream 1.
• Table 1 are indicated the molar compositions of the main streams generated under the conditions of molar flow rate, pressure and temperature mentioned.
• Table 2 are indicated the molar compositions of the main streams generated under the conditions of molar flow, pressure and temperature mentioned.

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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2009
  • 2009-11-02 FR FR0957731A patent/FR2952053B1/fr not_active Expired - Fee Related
• 2010
  • 2010-10-27 EP EP10788103A patent/EP2496537A2/de not_active Withdrawn
  • 2010-10-27 CN CN2010800477839A patent/CN102712551A/zh active Pending
  • 2010-10-27 KR KR1020127011139A patent/KR20130004562A/ko not_active Withdrawn
  • 2010-10-27 BR BR112012010345A patent/BR112012010345A2/pt not_active IP Right Cessation
  • 2010-10-27 US US13/505,325 patent/US20120277464A1/en not_active Abandoned
  • 2010-10-27 IN IN3071DEN2012 patent/IN2012DN03071A/en unknown
  • 2010-10-27 RU RU2012122741/04A patent/RU2012122741A/ru unknown
  • 2010-10-27 WO PCT/FR2010/052302 patent/WO2011051621A2/fr not_active Ceased

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