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    • 专利摘要:
    The invention relates to a process for the oligomerization of ethylene to alpha-olefins comprising an ethylene oligomerization step, a catalyst deactivation step, a product separation step, the reactor being provided with a cooling loop. (100, 101, 102) by means of which at least a portion of the reaction effluent is circulated through at least two exchangeable heat exchangers, said heat exchangers being alternately cleaned by an integrated cleaning device.
    公开号:FR3061034A1
    申请号:FR1663200
    申请日:2016-12-22
    公开日:2018-06-29
    发明作者:Catherine Boutrot；Nicolas JANOT；Xavier LIEGE；Etienne NIDERKORN；Jerome Pigourier；Daniel-Jean VINEL；Frederic Favre；Lionel Magna
    申请人:IFP Energies Nouvelles IFPEN；Axens SA；
    IPC主号:
    专利说明:

    @ Holder (s): IFP ENERGIES NOUVELLES Public establishment, AXENS Public limited company.
    ® Agent (s): IFP ENERGIES NOUVELLES.
    ® PROCESS FOR OLIGOMERIZATION OF OLEFINS USING A CLEANING DEVICE.
    FR 3,061,034 - A1 (57) The invention relates to a process for oligomerization of Othylene into alphaolefins comprising a step of oligomerization of ethylene, a step of deactivation of the catalyst, a step of separation of the products, the reactor being provided with a cooling loop (100, 101.102) by means of which at least part of the reaction effluent is circulated through at least two permutable heat exchangers, said heat exchangers being cleaned alternately by a device integrated cleaning.

    The invention relates to the field of oligomerization of ethylene. This oligomerization aims to produce alphaolefins used as co-monomer in polyethylene production processes. The oligomerization reaction is most often carried out in a liquid phase catalysis process. It is also highly exothermic requiring external cooling via heat exchangers. The side reactions of oligomerization are the production of very long oligomers and / or polymers. These polymers are mostly fouling, in particular they are deposited on the tubes of heat exchangers. This requires frequent process shutdowns, to isolate and clean the fouled heat exchanger, which adversely affects the efficiency and operability of the process and affects its production economy.
    Attempts to mitigate the problems associated with polymer deposits in process equipment are known to those skilled in the art. Most of these attempts have resulted in the use of various mechanical means such as high pressure water cleaning. This method has the disadvantage of having to open the exchanger and moreover requires a thorough drying of the latter before it is put back into service, humidity being a known poison of this type of catalysis.
    Cleaning with a solvent is possible, polyethylene being, at the right temperature conditions, soluble in most light hydrocarbons. The solvent used for cleaning is then loaded with polymers and heavy oligomers as well as with catalyst (or compounds derived from the catalyst, such as metals). Consequently, this has the drawback of requiring an external supply of solvent in addition to the investment in means allowing the separation of polymers, heavy oligomers and catalysts (or compounds derived from the catalyst) on the one hand and from the solvent on the other hand.
    The applicant in its research has developed a new process for the oligomerization of ethylene which is more efficient and which requires fewer stops for cleaning the equipment thanks to the integrated implementation of a process for cleaning said process equipment. , or even heat exchangers used in said oligomerization type processes of olefins.
    The invention also relates to an installation implemented in the method according to the invention.
    Summary of the invention
    The invention relates to a process for the oligomerization of ethylene into alphaolefins comprising a step of oligomerization of ethylene in a reaction section (1) comprising a reactor (10) in the presence of a catalyst, optionally a diluent, a step of deactivation of the catalyst contained in the reaction effluent, a step of evaporation of the products contained in the reaction effluent, to separate them from the deactivated catalyst, carried out in an evaporation section (2), a step of separation of the products contained in reaction effluent 103 in a separation section (3), said reactor being provided with at least one cooling loop (100 a / b, 101 a / b, 102 a / b) by means of which one makes circulate the reaction medium through at least two permutable heat exchangers able to be connected to at least one cooling loop, so that when at least one heat exchanger ur is in operation connected to at least one cooling loop, the other disconnected heat exchanger is subjected to a cleaning step by means of a cleaning device in which is circulated in a loop a solvent capable of cleaning said heat exchanger heat, the cleaning device comprising:
    - a cleaning solvent inventory flask (40),
    - a heat exchanger (43) for heating the cleaning solvent to a temperature above 130 ° C so as to allow the polymer deposited in the disconnected heat exchanger to dissolve,
    - a recirculation pump (42) allowing the cleaning solvent to circulate in a loop in the cleaning device between the solvent inventory tank (40), the heat exchanger (43) of the solvent and the heat exchanger disconnected that you want to clean.
    One of the advantages of the process according to the invention is to provide a means allowing rapid and effective cleaning of the process equipment, in particular of the exchangers used, without harming the profitability and the operability of the oligomerization process.
    Another advantage of the process is that it is easy to use and integrated with the various stages of the process, in particular by the use of cleaning solvent from the process itself.
    The method according to the invention makes it possible to correct the drawbacks of the prior art by minimizing the material investment and / or the loss in productivity and / or by minimizing the consumption of cleaning solvent. It allows the washing of the heat exchanger by dissolving in a hydrocarbon solvent the polymers formed and deposited on the walls of the heat exchanger. It also makes it possible to integrate the elimination of the heavy oligomers and / or polymers and / or spent catalysts contained in the cleaning solvent in the deactivation section of the catalyst and of evaporation by mixing at least part of the cleaning solvent. loaded with heavy oligomers and / or polymers and / or spent catalysts with the effluent from the oligomerization section.
    Brief description of the figures
    FIG. 1 describes an embodiment of the method implemented with the cleaning device according to the invention when one heat exchanger is in operation (12a) and the other is in cleaning (12b) with the cleaning device .
    Detailed description of the invention
    The invention relates to a process for the oligomerization of ethylene into alphaolefins comprising a step of oligomerization of ethylene in a reaction section (1) comprising a reactor (10) in the presence of a catalyst, optionally a diluent, a stage of deactivation of the catalyst contained in the reaction effluent (103), a stage of evaporation of the products contained in the reaction effluent, to separate them from the deactivated catalyst, carried out in an evaporation section (2), a stage of separation of the products contained in the reaction effluent in a separation section (3), said reactor being provided with at least one cooling loop (100 a / b, 101 a / b, 102 a / b) by means of which the reaction medium is circulated through at least two permutable heat exchangers capable of being connected to at least one cooling loop, so that when at least one heat exchanger their is in operation connected to at least one cooling loop, the other disconnected heat exchanger is subjected to a cleaning step by means of a cleaning device in which a solvent is circulated in a loop capable of cleaning said heat exchanger. heat, the cleaning device comprising:
    - a cleaning solvent inventory flask (40),
    - a heat exchanger (43) for heating the cleaning solvent to a temperature above 130 ° C so as to allow the polymer deposited in the disconnected heat exchanger to dissolve,
    - a recirculation pump (42) allowing the cleaning solvent to circulate in a loop in the cleaning device between the cleaning solvent inventory tank (40), the heat exchanger (43) of the cleaning solvent and the 'disconnected heat exchanger to be cleaned.
    Advantageously according to the invention, at least part of the cleaning solvent coming from the solvent loop of the cleaning device (406, 407) is sent in the step of evaporation of the products in the evaporation section (2).
    For reasons of clarity, the invention will be, in the rest of the text, explained with reference to FIG. 1 which describes an illustrative diagram of the process. In no case may the reference to FIG. 1 be limiting the scope of the process.
    The cleaning solvent used for cleaning, containing heavy oligomers and / or polymer and / or spent catalyst is called cleaning solvent loaded in the following text.
    Reaction section (1)
    According to the invention, the process for the oligomerization of ethylene into alphaolefins comprises a step of oligomerization of ethylene carried out in a reaction section (1) comprising a reactor (10) in the presence of a catalyst. Advantageously, the ethylene oligomerization reaction is a catalysis process in the liquid phase, generally homogeneous, in the presence or not of a diluent, with a catalyst of Ziegler type which generally comprises a compound of a metal such as titanium, chromium, zirconium and at least one organoaluminum compound. The reaction is preferably carried out at a temperature between room temperature and 200 ° C, preferably between 30 and 170 ° C and at a pressure between 0.5 and 20 MFb, preferably between 1.0 and 10 MPa. This oligomerization reaction is sometimes carried out in an inert diluent such as ortho-xylene or cyclohexane.
    Within the general framework of the invention, the process for oligomerization of ethylene can be a process for dimerization of ethylene to butene-1, a process for trimerization of ethylene to hexene-1 or a process for tetramerization ethylene to octene-1.
    The oligomerization reactions of ethylene are exothermic. The heat generated by the reaction must be extracted in order to avoid an uncontrolled rise in the temperature of the reaction medium. Depending on the temperature level reached, the consequences are a loss of selectivity by thermal degradation of the catalyst and of the reaction products. The heat of reaction generated in the reactor is extracted using at least one cooling loop (lines 100a / b, 101 a / b, 102a / b) comprising at least one heat exchanger (12a / b).
    Reaction effluent 103 from reaction section (1) of ethylene oligomerization comprises unconverted ethylene, alphaolefins such as butene-1, hexene-1, octene-1, and other reaction products from C4 to C30 + (that is to say comprising between 4 and more than 30 carbon atoms per molecule), as well as a possible diluent of the oligomerization reaction. Said effluent also comprises at least part of the catalyst. The reaction effluent (103) can be circulated in a heat exchanger (20) in which it is vaporized in the evaporation section (2).
    In the particular case of an ethylene dimerization process, this vaporization in the heat exchanger (20) is preferably carried out at a pressure equal to or substantially identical to that of the ethylene dimerization step and at a temperature of 80 ° C., allowing in the evaporation section (2), in particular in one or more flash flasks in the evaporation section (2), the separation of at least one gaseous phase and at least a liquid phase.
    Deactivation and evaporation section (2)
    According to the invention, in general, at the outlet of the oligomerization reaction section (1), the catalyst contained in the effluent (103) is subjected to a deactivation step carried out, preferably upstream of the section evaporation (2). This deactivation is carried out by any compound known to those skilled in the art for its inhibitory activity on the oligomerization catalyst. For example, an oxygenated or nitrogenous polar compound intended to deactivate substantially all of the catalyst present in effluent 103. Such inhibitors of nitrogenous catalysts are for example described in European patent EP-B-200654.
    The catalyst inhibitor used in the deactivation step is generally selected from amines, preferably primary or secondary amines of general formula FGFfeNH in which R 1 is hydrogen or a hydrocarbon radical and R 2 is a hydrocarbon radical, or linear or branched alcohols preferably having from 2 to 20 carbon atoms, more preferably from 5 to 15 carbon atoms or carboxylic acids such as n-octanoic acid or water or ammonia.
    When the catalyst inhibitor is selected from the amines, an inhibitor selected from the following compounds or their mixtures is preferably used: cyclohexylamine, ethyl-2-hexylamine, arylamine, stearylamine, oleylamine, aniline, N-methyl aniline, dibutylamine, didecylamine, mixtures of amines obtained from natural fatty substances such as tallow, palm oil or coconut oil.
    When the catalyst inhibitor is selected from alcohols, a linear or branched alcohol of 2 to 20 carbon atoms will be used, such as 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-hexanol , 2-ethyl-1-hexanol, 1-heptanol, 2- heptanol, 2-methyl-3-heptanol, 1-octanol, 2-octanol, 3-octanol, 1-decanol, 2-decanol, 3-decanol, 2 ethyl-1-decanol; a diol such as, for example, ethylene glycol, propanediols, butanediols or else a polyol such as glycerol, used alone or as a mixture. Preferably, 2-ethyl-1-hexanol will be used.
    When the catalyst inhibitor is selected from carboxylic acids, a linear or branched acid of 2 to 20 carbon atoms will be used, such as, for example, acetic acid, propionic acid, butyric acid, pentanoic acid ( valérique), hexanoic acid, 2-ethylhexanoic acid, octanoic acid (caprylic), dodecanoic acid, stearic acid, benzoic acid, 2-hydroxybenzoic acid, used alone or as a mixture . Preferably, 2-ethylhexanoic acid and octanoic acid (caprylic) will be used.
    After the catalyst deactivation step according to the invention, the reaction effluent from the deactivated reactor (103) (deactivation step not shown in FIG. 1), is subjected to an evaporation step to separate from a on the one hand the deactivated catalyst as well as the heavy by-products of the reaction and on the other hand the unconverted ethylene, the products formed as well as the possible diluent. This evaporation step is preferably carried out by vaporization of a part of the reaction effluent so as to obtain one or more vapor phases containing the unconverted ethylene, the products formed and the possible diluent. This or these vapor phases are advantageously sent (see lines 203, 207) to the separation section (3) in which the various products of interest formed are separated from each other.
    According to the invention, in the stage of evaporation of the products contained in the reaction effluent 103 carried out in the evaporation section (2), the catalyst is separated from all of the products of the reaction.
    In a variant of the process of the invention, the evaporation section (2) can comprise at least one flash flask (21, 23) (flasks / separators with liquid-vapor equilibrium) and at least one vaporizer or thin film evaporator or falling film (22) for vaporizing the desired product.
    In the particular case of a process for the dimerization of ethylene, the reaction effluent 103, preferably originating from the heat exchanger (20), alone or mixed with at least part of the cleaning solvent derived from flow 406 -407 (flow 211, 201), can be vaporized in a first flash balloon 21 under conditions making it possible to separate a gaseous phase (207) essentially containing butene-1 and other hydrocarbon products C6 and C8 and ethylene and a second liquid phase (202) containing the deactivated catalyst. It is possible in one embodiment that at least part of the cleaning solvent from flow 406-407 (flow 213) is sent as a mixture with the effluent (103) upstream of the heat exchanger (20) . Advantageously, at least part of the liquid phase (202), alone or mixed with at least part of the cleaning solvent from flow 406-407 (flow 212) can then be directed to a thin film evaporator or evaporator (22 ) in which it is evaporated under conditions allowing the separation of a gas phase (203) essentially containing butene-1 and optionally heavier hydrocarbon products, and a liquid phase enriched in concentrated deactivated catalyst (204). The evaporation rate in the thin film or falling film evaporator is generally around 99% by weight relative to the liquid phase entering the evaporator. At least part of the liquid phase enriched in concentrated deactivated catalyst (204) alone or mixed with at least part of the cleaning solvent from stream 406-407 (stream 210) is advantageously expanded and flashed in a flash balloon (23) generating a vapor phase (205) substantially free of polymer and deactivated catalyst and a liquid phase (206) concentrated in polymers and deactivated catalyst (206). Advantageously, the gaseous phases (207, 203) resulting from the evaporation step carried out in the evaporation section (2) and containing essentially butene-1 and ethylene as well as heavier hydrocarbon products are condensed under the form of a liquid product which is sent in the separation step carried out in the separation section (3) in which the different products will be separated from each other.
    In the particular case of an ethylene trimerization process, the reaction effluent from the reactor is preferably sent to the deactivation and evaporation section (2) advantageously comprising flash flasks. The catalyst in the reaction effluent can be deactivated by the injection of ethyl-2-hexanol used as an inhibitor. Mixing can be achieved using an in-line dynamic mixer (not shown in Figure 1). In particular, the reaction medium from the reactor can be expanded in a first flash balloon at a pressure preferably of 2.4 MPa. Said expanded reaction medium can then be vaporized by heating to a temperature preferably of 175 ° C. This vaporization is carried out in a heat exchanger. The vapor phase is then separated from the liquid phase in a flask. The vapor phase is sent to the separation section (3). The liquid phase resulting from the first flash balloon is expanded in a second flash balloon at a pressure preferably of 1.1 MPa. Said expanded liquid phase is then vaporized by heating to a temperature preferably of 175 ° C. This vaporization is carried out in a heat exchanger. The vapor phase is then separated from the liquid phase in a flask. The vapor phase is sent to the separation section 3 and the liquid phase resulting from the second flash balloon is expanded to a pressure preferably of 0.2 MPa. Said expanded liquid phase is then vaporized by heating to a temperature preferably of 200 ° C. This vaporization is preferably carried out in a thin film evaporator. The deactivated catalyst as well as the heavy by-products separated in the deactivation and evaporation section (2) are pumped and sent to an incinerator.
    Separation section (3)
    In the general context of the invention which relates to a process for the oligomerization of olefins, the separation step is advantageously carried out in the separation section (3) which separates the different products formed in the oligomerization reaction of olefins.
    Oligomeric olefins from the oligomerization of ethylene have a higher molecular weight than unreacted ethylene. In general, unreacted ethylene has a lower boiling temperature than that of the oligomeric olefins resulting from the reaction. Any separation means known to those skilled in the art taking advantage of these differences in volatility and molecular weight between the products to be separated can be used. Advantageously according to the invention, the separation means used in the separation step in the separation section (3) are distillation columns of any type.
    In the case of a process for a dimerization process of ethylene, only unreacted ethylene (stream 306) is separated only from butene-1 (stream 301) and from C6 + hydrocarbon products (stream 304).
    In the case of a process of an ethylene trimerization process, unreacted ethylene is preferably separated (stream 306), the products of interest such as hexene-1 and optionally diluent (stream 301 and possibly 302, 303 ...) and the fractions of heavier compounds (flow 304).
    The separation section (3) is advantageously provided with several distillation columns (not shown in FIG. 1).
    Advantageously according to the invention, the unreacted ethylene separated in the separation step in the separation section (3) is recycled to the reactor (flow 306).
    In the particular case of an ethylene trimerization process, the separation section (3) can comprise at least four distillation columns arranged as follows: a first distillation column in which the unconverted ethylene is separated in a top fraction of the rest of the compounds in the bottom fraction; a second distillation column in which the bottom fraction from the first column is separated into a top fraction comprising hexene-1 and butene-1 and a bottom fraction. Said bottom fraction is mainly composed of the diluent; a third distillation column in which the top fraction of the second distillation is separated into a top fraction mainly comprising butene-1 and into a bottom fraction mainly comprising hexene-1 reaction product; a fourth column in which the bottom fraction of the second distillation is separated into an overhead fraction comprising mainly diluent which can be recycled to the reactor and into a bottom fraction comprising the heavier products in particular of C8 + (with 8 carbon atoms or more). The deactivated catalyst and the heavy by-products are removed.
    In a variant of the process according to the invention, the cleaning solvent consists of the diluent. In a variant of the process according to the invention, the cleaning solvent consists of the bottom fraction comprising the heavier products, in particular of C8 + originating from the bottom of the fourth column. In a variant of the process according to the invention, the cleaning solvent consists of the bottom product from the second column.
    12a / 12b heat exchanger cleaning section
    According to the invention, the reactor used in reaction section 1 is provided with a cooling loop (100a / b, 101 a / b, 102a / b) by means of which at least the reaction medium is circulated through at least two heat exchangers to allow the heat generated by the oligomerization reaction to be extracted in order to avoid an uncontrolled rise in the temperature of the reaction medium in the reactor.
    According to the invention, the heat exchangers (12a, 12b) used are interchangeable and are able to be connected to at least one cooling loop, so that when at least one heat exchanger is in operation connected to at least one cooling loop, the other heat exchanger is disconnected and subjected to a cleaning step by means of a cleaning device in which a solvent is circulated in a loop capable of cleaning said heat exchanger, said cleaning device comprising:
    - a cleaning solvent inventory flask (40),
    a heat exchanger (43) making it possible to heat the cleaning solvent to a temperature higher than 130 ° C., preferably higher than 150 ° C., more preferably higher than 170 ° C., even more preferably higher than 180 ° C so as to allow the polymer deposited in the disconnected heat exchanger to dissolve,
    - a recirculation pump (42) allowing the cleaning solvent to circulate in a loop in the cleaning device between the cleaning solvent inventory tank (40), the heat exchanger (43) of the cleaning solvent and the 'disconnected heat exchanger to be cleaned.
    Cleaning is carried out by circulating the hot solvent using the recirculation pump (42) via the pipes 402, 403, 404, 405.
    According to the invention, the pressure of the cleaning solvent inventory flask (40) is preferably fixed so as to keep the cleaning solvent in liquid form. This pressure is preferably between 0.5 and 3 MPa.
    The method according to the invention can use several heat exchangers (12a, 12b) capable of being connected to at least one cooling loop making it possible to extract the heat generated by the oligomerization reaction. Preferably 2 or 3 or 4 or 5 heat exchangers can be used. Figure 1 has two cooling loops each comprising a heat exchanger implemented alternately. The valves 15a / 16a are open and connected to the reactor (10) when the heat exchanger (12a) is in operation with the cooling loop (100a, 101a, 102a). During this time, the valves 15b / 16b are closed thus isolating the second cooling loop (100b, 101b, 102b) from the reactor 10 and allowing its cleaning by the cleaning device.
    The cleaning solvent is advantageously chosen from saturated hydrocarbons such as butane, isobutane, pentane, cyclohexane, methylecyclohexane, n-hexane, heptane, octane, decane, dodecane; unsaturated hydrocarbons such as a monoolefin or a diolefin comprising for example from 4 to 20 carbon atoms; aromatic hydrocarbons such as benzene, toluene, ortho meta or para-xylene, cumene, mesitylene, ethylbenzene; a petrol, diesel or kerosene cut; isoparaffins such as Isopar E or C; used alone or as a mixture. The cleaning solvent can come from the process itself, in particular from the separation section (3). Preferably, at least part of the cleaning solvent, or even all of the cleaning solvent, comes from the separation step of the separation section 3 (flow 305). Preferably, at least part of the cleaning solvent or even all of the cleaning solvent comes from the fractions of heavier compounds and / or any diluent separated from the separation step of the separation section 3.
    In a variant of the invention a filter (39) can be implemented on the cleaning solvent circulation loop (402, 403, 404, 405). This filter will capture possible pieces of polymers that have come off the heat exchanger which is cleaned without being completely dissolved.
    Advantageously according to the invention, at least part of the cleaning solvent loaded from the solvent loop of the cleaning device (406) is sent in the step of evaporation of the products in the evaporation section (2).
    For example, once the polymer has dissolved in the cleaning solvent, at least part of the cleaning solvent loaded can be directed to the product evaporation step, especially in the evaporation section (2) (see the pipes 406, 407, 211, 212, 210 and 213 in Figure 1).
    In a variant of the process, once the polymer has dissolved in the cleaning solvent, at least part of the cleaning solvent loaded (406-407) is sent as a mixture with part of the reaction effluent 103 in the evaporation section (2), either upstream (flow 213), or downstream (flow 211) of the heat exchanger (20) when this heat exchanger is present.
    In a variant of the process, once the polymer has dissolved in the cleaning solvent, at least part of the cleaning solvent loaded (406-407) is sent as a mixture with the liquid phase (202) coming from the flash balloon (21) ( flow 212) used in the evaporation section (2).
    In a variant of the process, once the polymer has dissolved in the cleaning solvent, at least part of the cleaning solvent loaded (406-407) is sent as a mixture with the liquid phase 204 from the vaporizer or from the film evaporator thin (22) (flow 210) used in the evaporation section (2).
    The concentration of polymers and heavy oligomers in the cleaning solvent loaded is advantageously less than 5% by weight, and preferably less than 1% by weight relative to the cleaning solvent.
    In a variant of the invention, once the polymer has dissolved in the cleaning solvent, at least part of the cleaning solvent loaded, preferably withdrawn from the stream (406) (408), is expanded and directed to a vaporization step partial in by means of a flash balloon (46) making it possible to produce at least one vapor phase (409) and at least one liquid phase (410). The partial vaporization resulting from this expansion has two advantages. First of all, it makes it possible to generate a vapor phase of which the content of polymers, heavy oligomers and catalyst is sufficiently low to allow it to be directed directly after any condensation (s) in the exchanger (45) (line 409 , 412) to the separation section (3) of the process. At least part of this vapor phase can also, after condensation (s) in the exchanger 45, be collected in the recipe flask 41 and then returned to the solvent inventory flask 40 (flow 413, 414) in order to serve as new to cleaning the exchanger according to the method of the invention.
    Furthermore, this partial vaporization makes it possible to lower the temperature of the stream 410/411 of the liquid phase recovered from the flash balloon 46 so as to be able to reinject it, preferably as a mixture with the stream (407), into the evaporation section ( 2) without requiring cooling. In fact, too high a temperature in the sections downstream of the reactor before total separation of the catalyst, even deactivated, can lead to degradation of the products. In such an implementation, a recirculation pump (44) can be implemented between the streams 410 and 411. It is also possible to implement a heat exchanger in the pipe 407 (47).
    The partial spraying of the loaded cleaning solvent is preferably carried out by an expansion since the use of a heat exchanger would involve a high risk of fouling of the latter.
    According to another variant of the process of the invention, at least part of the cleaning solvent comes from the separation step of the separation section (3) (flow 305). Preferably, at least part of the cleaning solvent comes from the fractions of heavier compounds and / or any diluent separated from the separation step, thus avoiding the need for an external supply of cleaning solvent. Preferably, the cleaning solvent consists exclusively of the heavier hydrocarbon products, recovered from the separation section (3) (flow 304). A fraction of the heavier hydrocarbon products can be directed (305) to the cleaning solvent inventory flask 40. In this way no external addition of solvent solvent is required. Line 305 may be provided with a heat exchanger (48).
    The invention also relates to an installation implemented in the method according to the invention.
    The installation according to the invention includes:
    a reaction section (1) comprising a reactor (10), an evaporation section (2) of the reaction effluent, a separation section (3), said reactor being provided with at least one cooling loop (100a / b, 101 a / b, 102a / b) by means of which the reaction medium is circulated through at least two permutable heat exchangers capable of being connected to at least one cooling loop, so that when at least one exchanger heat is in operation connected to at least one cooling loop, the other disconnected heat exchanger is subjected to a cleaning step by means of a cleaning device in which a solvent capable of cleaning said heat exchanger is circulated , the cleaning device comprising:
    - a cleaning solvent inventory flask (40),
    - a heat exchanger (43) for heating the cleaning solvent to a temperature above 130 ° C so as to allow the polymer deposited in the disconnected heat exchanger to dissolve,
    - a recirculation pump (42) allowing the cleaning solvent to circulate in a loop in the cleaning device between the cleaning solvent inventory tank (40), the heat exchanger (43) of the cleaning solvent and the 'disconnected heat exchanger to be cleaned.
    Advantageously, the cleaning device is connected to the evaporation section (2) by at least one conduit making it possible to send at least part of the cleaning solvent to said evaporation section (2) of the reaction effluent.
    Example 1: Application of the process according to the invention to a process for the dimerization of ethylene
    The production of butene-1 is carried out by the homogeneous catalytic dimerization in the liquid phase of ethylene. The device according to the invention as described in Figure 1 is implemented. The catalyst is obtained by interaction of n-butyl titanate, tetrahydrofuran and triethylaluminum as described in Example 1 of patent EP135441.
    During the ethylene dimerization reaction, the pressure of reactor 10 is 2.2 MPa and the temperature is 53 ° C.
    The reactor is cooled using two cooling loops each having a heat exchanger (12a and 12b). The switchable heat exchanger 12b is disconnected after an operating period of 2 months. In the example, it is considered that this exchanger 12b is cleaned while the exchanger 12a is in operation.
    Reaction effluent 103 contains ethylene, the butene-1 produced as well as certain C6 and C8 + hydrocarbon products (mainly octenes) formed during side reactions in the reactor (10). The reaction effluent 103 is introduced into the deactivation and evaporation section (2). The reaction effluent (103) is brought into contact with decylamine used as catalyst inhibitor. The section (2) includes a heat exchanger (20) in which the reaction effluent (103) is vaporized at a pressure of 2.1 MPa and at the temperature of 80 ° C and sent to the flash balloon (21) in order to separating a gas phase (207) containing essentially butene-1 and ethylene and a second liquid phase (202) containing the deactivated catalyst. The liquid phase (202) from the flash balloon (21) is then directed into a thin film vaporizer (22) in which it is evaporated at a pressure substantially identical to that of the flash balloon (21), under conditions allowing separation a gas phase (203) containing ethylene, butene-1, as well as heavier hydrocarbon products (C6 +), and a liquid phase enriched in concentrated deactivated catalyst (204). This liquid phase (204) obtained is expanded and flashed in a flash balloon (23) generating a vapor phase (205) substantially free of polymer and deactivated catalyst and a concentrated liquid phase (206) and polymers and deactivated catalyst. The flow compositions from the deactivation and evaporation section are described in Table 1 below.
    % weight Reaction effluent (103) gas phase (207) gas phase (203) gas phase (205) liquid 3rd flash (206) Methane 0.47 0.92 0.11 0.00 0.00 Ethylene 12.03 20.69 5.41 0.00 0.00 Ethane 0.90 1.46 0.48 0.00 0.00 Butene-1 80.84 74.59 86.03 83.33 27.27 N-Butane 0.12 0.10 0.13 0.00 0.00 Hexes 5.08 2.10 7.21 16.67 27.27 Hexane 0.30 0.10 0.42 0.00 4.55 C8 + 0.16 0.03 0.21 0.00 9.09 triethylaluminium 0.00 0.00 0.00 0.00 0.00 Decylamine 0.01 0.00 0.00 0.00 4.55 Catalyst deactivated 0.09 0.00 0.00 0.00 27.27
    The different vapor phases 207 and 203 from the flash tank (21) and the thin film vaporizer (22), substantially free of deactivated catalyst, are condensed in the form of a liquid product which can be brought into a corresponding distillation section. to the 5 separation section (3) in which the different products will be separated. In the distillation section (3), the ethylene is separated on the one hand and butene-1 and the heavier compounds on the other hand in a second distillation column (not shown). The fraction enriched in ethylene is recycled to the reactor (stream 306). The separation between butene-1 (stream 301) and the heavier compounds (C6 +, stream 304) is carried out in a second distillation column (not shown).
    For cleaning the exchanger 12b, the device according to the invention is used. N-hexane is used as a cleaning solvent. A circulation (lines 402, 403, 404, 405) of the cleaning solvent is established using the pump (42) between the balloon (40) of solvent inventory and the exchanger 12b to be cleaned. A heat exchanger 43 on this loop 15 makes it possible to heat the solvent to a temperature of 180 ° C.
    The pressure of the cleaning solvent (n-hexane) inventory tank (40) is approximately 1.4 MPa absolute so as to maintain it in liquid form. Once cleaning is complete, the solvent loaded with polymer and catalyst residues is directed via lines 406, 407 and 211 to the flash balloon (21).
    The process is implemented without stopping and makes it possible to avoid opening equipment, in particular heat exchangers to clean them, which represents a gain in labor and avoids the risk of accident.
    权利要求:
    Claims (16)
    [1" id="c-fr-0001]
    1. Process for the oligomerization of ethylene into alphaolefins comprising a step of oligomerization of ethylene in a reaction section (1) comprising a reactor (10) in the presence of a catalyst, optionally a diluent, a deactivation step of the catalyst contained in the reaction effluent, a stage of evaporation of the products contained in the reaction effluent, to separate them from the deactivated catalyst, carried out in an evaporation section (2), a stage of separation of the products contained in the 'reaction effluent in a separation section (3), said reactor being provided with at least one cooling loop (100a / b, 101 a / b, 102a / b) by means of which the reaction medium is circulated through at least two permutable heat exchangers able to be connected to at least one cooling loop, so that when at least one heat exchanger is in operation conn ected to at least one cooling loop, the other disconnected heat exchanger is subjected to a cleaning step by means of a cleaning device in which a solvent is circulated in a loop capable of cleaning said heat exchanger, the cleaning including:
    - a cleaning solvent inventory flask (40),
    - a heat exchanger (43) for heating the cleaning solvent to a temperature above 130 ° C so as to allow the polymer deposited in the disconnected heat exchanger to dissolve,
    - a recirculation pump (42) allowing the cleaning solvent to circulate in a loop in the cleaning device between the cleaning solvent inventory tank (40), the heat exchanger (43) of the cleaning solvent and the 'disconnected heat exchanger to be cleaned.
    [2" id="c-fr-0002]
    2. Method according to claim 1 wherein at least part of the cleaning solvent from the solvent loop of the cleaning device (406) is sent in the step of evaporation of the products in the evaporation section (2) .
    [3" id="c-fr-0003]
    3. Method according to claim 1 or 2 in which the reaction medium 103 is circulated in a heat exchanger 20 in which it is vaporized in the evaporation section (2).
    [4" id="c-fr-0004]
    4. Method according to one of the preceding claims, in which the unreacted ethylene separated in the separation step in the separation section (3) is recycled to the reactor (flow 306).
    [5" id="c-fr-0005]
    5. Method according to one of the preceding claims wherein the heat exchanger (43) heats the cleaning solvent to a temperature above 150 ° C so as to allow the dissolution of the polymer deposited in the disconnected heat exchanger.
    [6" id="c-fr-0006]
    6. Method according to one of the preceding claims wherein the concentration of polymers and heavy oligomers in the loaded solvent is less than 5% by weight relative to the cleaning solvent.
    [7" id="c-fr-0007]
    7. Method according to one of the preceding claims in which the cleaning solvent is chosen from saturated hydrocarbons; unsaturated hydrocarbons; aromatic hydrocarbons; a petrol, diesel or kerosene cut; isoparaffins; used alone or as a mixture.
    [8" id="c-fr-0008]
    8. Method according to one of the preceding claims wherein at least part of the cleaning solvent comes from the separation step of the separation section 3 (flow 305).
    [9" id="c-fr-0009]
    9. Method according to one of the preceding claims, in which at least part of the cleaning solvent comes from the fractions of heavier compounds and / or of an optional diluent separated from the separation step.
    [10" id="c-fr-0010]
    10. Method according to one of the preceding claims in which a filter (39) is implemented on the cleaning solvent circulation loop 402, 403, 404, 405.
    [11" id="c-fr-0011]
    11. Method according to one of the preceding claims in which once the polymer has dissolved in the cleaning solvent, at least part of the cleaning solvent loaded is expanded and directed to a partial vaporization step in by means of a flash balloon 46 making it possible to produce at least one vapor phase (408) and at least one liquid phase (410).
    [12" id="c-fr-0012]
    12. Method according to one of claims 1 to 11 wherein the oligomerization process of ethylene is a dimerization process of ethylene into butene-1.
    [13" id="c-fr-0013]
    13. Method according to one of claims 1 to 11 wherein the oligomerization process of ethylene is a trimerization process of ethylene into hexene-1.
    [14" id="c-fr-0014]
    14. Method according to one of claims 1 to 11 wherein the oligomerization process of ethylene is a tetramerization process of ethylene into octene-1.
    [15" id="c-fr-0015]
    15. Installation including:
    a reaction section (1) comprising a reactor (10), a section (2) for evaporation of the reaction effluent, a separation section (3), said reactor being provided with a cooling loop (100a / b, 101a / b, 102a / b) by means of which at least one of the reaction medium is circulated through at least two permutable heat exchangers capable of being connected to at least one cooling loop, so that when at least one exchanger heat is in operation connected to at least cooling loop, the other disconnected heat exchanger is subjected to a cleaning step by means of a cleaning device in which a solvent is circulated in a loop capable of cleaning said heat exchanger heat, the cleaning device comprising:
    - a cleaning solvent inventory flask (40),
    - a heat exchanger (43) for heating the cleaning solvent to a temperature above 130 ° C so as to allow the polymer deposited in the disconnected heat exchanger to dissolve,
    - a recirculation pump (42) allowing the cleaning solvent to circulate in a loop in the cleaning device between the cleaning solvent inventory tank (40), the heat exchanger (43) of the cleaning solvent and the 'disconnected heat exchanger to be cleaned.
    [16" id="c-fr-0016]
    16. Installation according to claim 15 in which the cleaning device is connected to the evaporation section (2) by at least one conduit making it possible to send at least part of the cleaning solvent to said evaporation section (2) of the reaction effluent.
    1/1
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    同族专利:
    公开号 | 公开日
    TW201840516A|2018-11-16|
    ES2822341T3|2021-04-30|
    KR20180073501A|2018-07-02|
    JP2018108983A|2018-07-12|
    US10370307B2|2019-08-06|
    US20180179122A1|2018-06-28|
    CN108218661A|2018-06-29|
    FR3061034B1|2019-05-31|
    EP3338884A1|2018-06-27|
    EP3338884B1|2020-07-15|
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    法律状态:
    2017-12-14| PLFP| Fee payment|Year of fee payment: 2 |
    2018-06-29| PLSC| Publication of the preliminary search report|Effective date: 20180629 |
    2019-12-24| PLFP| Fee payment|Year of fee payment: 4 |
    2020-12-29| PLFP| Fee payment|Year of fee payment: 5 |
    2021-12-27| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1663200A|FR3061034B1|2016-12-22|2016-12-22|OLIGOMERIZATION PROCESS OF OLEFINS USING A CLEANING DEVICE|
    FR1663200|2016-12-22|FR1663200A| FR3061034B1|2016-12-22|2016-12-22|OLIGOMERIZATION PROCESS OF OLEFINS USING A CLEANING DEVICE|
    EP17306800.8A| EP3338884B1|2016-12-22|2017-12-18|Oligomerization method of olefins using a cleaning device|
    ES17306800T| ES2822341T3|2016-12-22|2017-12-18|Olefin oligomerization process using a cleaning device|
    JP2017243341A| JP7025916B2|2016-12-22|2017-12-20|Oligomerization method using a cleaning device|
    KR1020170177426A| KR20180073501A|2016-12-22|2017-12-21|Process for the oligomerization of olefins employing a cleaning device|
    US15/850,641| US10370307B2|2016-12-22|2017-12-21|Process for the oligomerization of olefins employing a cleaning device|
    TW106144954A| TW201840516A|2016-12-22|2017-12-21|Process for the oligomerization of olefins employing a cleaning device|
    CN201711405935.8A| CN108218661A|2016-12-22|2017-12-22|Use the alkene oligomerization process of cleaning device|
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