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    • 专利摘要:
    The subject of the invention is a process for the recovery / purification of (meth) acrylic acid which does not use azeotropic solvent and which is based on the implementation of two purification columns of a reaction mixture comprising acid ( meth) acrylic acid. The method according to the invention includes a dry vacuum pump condensation system, making it possible to reduce the quantity of ultimate aqueous discharges. The invention also relates to a suitable installation for the implementation of this method.
    公开号:FR3033558A1
    申请号:FR1552049
    申请日:2015-03-12
    公开日:2016-09-16
    发明作者:Sandeep Jain；Christian Lacroix；Michel Fauconet
    申请人:Arkema France SA；
    IPC主号:
    专利说明:

    [0001] FIELD OF THE INVENTION The present invention relates to the production of (meth) acrylic acid. It more particularly relates to a process for the recovery / purification of (meth) acrylic acid which does not use azeotropic solvent and based on the use of two columns for the purification of a reaction mixture comprising acid ( meth) acrylic acid. The method according to the invention includes a dry vacuum pump condensation system, making it possible to reduce the quantity of ultimate aqueous discharges. The invention also relates to a suitable installation for the implementation of this method.
    [0002] TECHNICAL BACKGROUND AND TECHNICAL PROBLEM For decades industrialists have been developing processes for synthesizing acrylic acid. The process, which today is the most widely exploited industrially, implements a catalytic oxidation reaction of propylene in the presence of oxygen.
    [0003] This reaction is generally carried out in the gaseous phase, and most often in two stages: the first step carries out the substantially quantitative oxidation of propylene to a mixture rich in acrolein, then, in the second step, the selective oxidation of the acrolein to acrylic acid. The reaction conditions of these two steps, carried out in two reactors in series or in a single reactor containing the two series reaction steps, are different and require catalysts adapted to the reaction; however, it is not necessary to isolate the intermediate acrolein in this two-step process. The gaseous mixture resulting from the second step consists, apart from acrylic acid: impurities from the first reaction stage which have not reacted; - incondensable light compounds under the conditions of temperature and pressure usually used, not transformed in the first stage or formed in the second stage: nitrogen, unconverted oxygen, carbon monoxide and carbon dioxide formed in small quantities by ultimate oxidation or rotating in circles, by recycling, in the process; condensable light compounds which are not converted in the first stage or formed in the second stage: water, unconverted acrolein, light aldehydes such as formaldehyde and acetaldehyde, formic acid and acetic acid; or propionic acid; heavy compounds: furfuraldehyde, benzaldehyde, maleic acid and anhydride, benzoic acid, 2-butenoic acid, phenol, protoanemonin.
    [0004] The complexity of the gaseous mixture obtained in this process requires carrying out a set of operations to recover the acrylic acid contained in this gaseous effluent and convert it into an acrylic acid grade compatible with its end use, for example the production of acrylic acid polymers, or the production of acrylic ester polymers.
    [0005] The first step of this recovery / purification step is an extraction of acrylic acid by countercurrent absorption in a solvent, usually water supplied from an external source and / or from the process. The amounts of water and gaseous reaction mixture are such that the mass content of acrylic acid in the crude aqueous solution produced is generally in the range of 40 to 80%. However, there is a very important economic problem, mainly because of the expensive energy required to remove the water used as acrylic acid absorption solvent, since the effective removal of the Water without undue loss of (meth) acrylic acid is complicated by the existence of interactions (hydrogen bonds) between the two compounds. Thus, this separation operation is generally carried out on an industrial scale by distillation with a third azeotropic solvent, which contributes to increasing the number of distillation columns and their associated energy costs. On the other hand, the multiplication of the distillation columns entails an additional cost related to the additional consumption of polymerization inhibitors which must be introduced on each of said columns, in order to carry out the purification of the desired product and the elimination of the -products avoiding problems of fouling of the apparatus by polymerization of the monomer. An alternative to this process which uses water as the acrylic acid absorption solvent is to use a hydrophobic heavy solvent to extract acrylic acid, but such a process does not simplify the purification process of the acrylic acid. acrylic acid. Recently, to overcome these various drawbacks, new "solvent-free" acrylic acid recovery / purification technologies have emerged, involving a reduced number of purification steps and suppressing the introduction of external organic solvent.
    [0006] In the process for the production of acrylic acid described in US Pat. No. 7,151,194, the gaseous reaction mixture is sent to an absorption column and put in contact with an aqueous absorption solution to obtain an aqueous solution of acid. acrylic, which is then distilled in the absence of azeotropic solvent.
    [0007] A crude acrylic acid stream is obtained at the bottom or side draw off from the distillation column, which is then sent to a crystallization purification unit. A disadvantage of this process is that the introduction of external water as an absorption solvent makes it difficult to remove the water at the head of the absorption column without significant loss of acrylic acid, and the recovery of a quality of crude acrylic acid at low side-draw water concentration, when this process is involved in a 2-column configuration. EP 2,066,613 discloses a process for recovering acrylic acid without the use of external water or an azeotropic solvent and employing only two purification columns of the cooled gaseous reaction mixture: a) a dehydration column; b) and a finishing column (or purification column) fed by a part of the foot flow of the dehydration column. The dewatering column generally operates at atmospheric pressure or slightly higher. In the dehydration column, the gas stream distilled at the top is condensed and returned partially to the dewatering column as reflux to absorb acrylic acid. The finishing column generally operates at a pressure below atmospheric pressure, allowing operation at relatively low temperatures, thereby avoiding polymerization of the unsaturated products present, and minimizing the formation of heavy by-products. In the finishing column, the overhead distillate comprising water and light by-products is condensed and recycled at the bottom of the first column, and a stream comprising acrylic acid enriched in heavy by-products is removed in foot to be used optionally for the production of acrylic esters.
    [0008] A stream of purified acrylic acid corresponding to a technical grade is recovered by lateral withdrawal in the form of liquid or vapor. The technical acrylic acid obtained is generally of purity greater than 98.5% by weight and contains less than 0.5% by weight of water. In this process, a portion of the streams (from the bottom of the dehydration column or from the top of the finishing column) is advantageously returned to the heating / reboiler devices of the dehydration column and / or used to cool the gaseous reaction mixture. which makes it possible to optimize the energy requirements of the process. Despite the advantages afforded by the process described in EP 2 066 613, there still remain disadvantages related to its implementation. In particular, at the top of the finishing column which operates under vacuum, the condenser releases residual vapors comprising organic impurities which must be removed, for example by incineration, which is detrimental to the environment. The vacuum generating systems available to reduce the operating pressure of the distillation columns are numerous (see, for example, Engineering Techniques, Vacuum Pumps, B4030, 10/11/1983). Volumetric pumps which generate the vacuum are generally distinguished by using liquid seals (oils, organic products or water), such as, for example, vane pumps and liquid ring pumps, and so-called "drive" pumps. in which it is the flow of a fluid that creates the vacuum (ejector pumps, jet steam, ...). The most commonly used systems involve water jet or steam jet ejectors or liquid ring pumps, mainly water ring pumps. These systems are not suitable for reducing the working pressure of the finishing column of a solventless (meth) acrylic acid purification process, such as that described in EP 2,066,613. systems, for example described in US 6,677,482 or US Pat. No. 7,288,169, use water vapor and generate in large quantities aqueous effluents containing acrylic acid and organic impurities, which can not be economically recycled in the process. purification loop formed by the dehydration column and the finishing column. Indeed, it has been found that the recycling of too much water at the dehydration column leads to significant losses of acrylic acid at the head of this column, unless using an oversized column but causing an expensive investment. These aqueous effluents therefore need to be sent to a water treatment station or directly into a thermal oxidizer, thus causing a loss of noble product on the one hand and a rejection harmful to the environment on the other hand. The vents from these vacuum systems, rich in incondensable compounds, incinerated or sent directly into the atmosphere, release in the first case oxidation products and in the second case organic compounds polluting the environment. There is therefore still a need to eliminate and / or reduce the generation of aqueous discharges in a solventless recovery / purification process for vacuum operation of the finishing column. The inventors have now discovered that the use of a dry vacuum pump related to the operation of the finishing column in a solvent-free acrylic acid recovery / purification process makes it possible to meet this need, with the economic advantages and resulting environmental. It has furthermore become apparent to the inventors that this invention could be applied to acrylic acid produced from sources other than propylene, to methacrylic acid, as well as to those acids derived from renewable raw materials, which are likely to pose the same problems of purification. SUMMARY OF THE INVENTION The present invention relates primarily to a process for recovering (meth) acrylic acid without the use of an azeotropic solvent from a gaseous reaction mixture comprising (meth) acrylic acid obtained from gas phase oxidation of a precursor of (meth) acrylic acid, comprising at least the following steps: i) subjecting the gaseous reaction mixture to dehydration without the use of azeotropic solvent in a first column called dehydration column, leading to a head flow of which at least a portion is condensed and returned to the dehydration column as reflux, and a foot flow; ii) at least partially the dehydration column foot stream is subjected to distillation at a pressure below atmospheric pressure in a second column called finishing column, leading to a head flow, and a foot flow containing heavy compounds; iii) recovering a flow of (meth) acrylic acid by lateral withdrawal of the finishing column, and / or at the bottom of the finishing column; Said method being characterized in that the top flow of the finishing column is at least partly subjected to a dry vacuum pump condensation system, forming a condensate which is returned to the dewatering column, and a gaseous effluent ultimate.
    [0009] In the present invention, the term "(meth) acrylic" means "acrylic" or "methacrylic". The term "azeotropic solvent" denotes any organic solvent having the property of forming an azeotropic mixture with water. The term "light" qualifying by-product compounds refers to those compounds whose boiling point is lower than that of (meth) acrylic acid, and by analogy, the term "heavy" refers to those compounds whose boiling is greater than that of (meth) acrylic acid.
    [0010] The process according to the invention may furthermore comprise other steps for further purification of the (meth) acrylic acid stream recovered in step iii). According to certain particular embodiments, the invention also has one or, preferably, several of the advantageous features listed below: the dry vacuum pump condensation system comprises at least one condenser and a dry vacuum pump ( which can also be called primary dry vacuum pump); The dry vacuum pump condensation system may optionally comprise, in addition to the primary dry vacuum pump, a liquid separator, one or more flame arrestors, one or more filters, sealing systems and isolation, a pump or a combination of dry booster pumps, such as for example "Roots" type pumps (volumetric pumps using two synchronized rotors 15 rotating in the opposite direction); - At least a portion of the flow of (meth) acrylic acid withdrawn laterally is subjected to a dry vacuum pump condensation system, the same or different from that used for the top flow of the finishing column.
    [0011] According to one embodiment of the invention, the precursor of the (meth) acrylic acid is acrolein. According to one embodiment of the invention, acrolein is obtained by oxidation of propylene or by oxyhydrogenation of propane. According to one embodiment of the invention, the precursor of (meth) acrylic acid is methacrolein. According to one embodiment of the invention, methacrolein is obtained by oxidation of isobutylene and / or tert-butanol. According to one embodiment of the invention, methacrolein is obtained from the oxidation of hydrogenation of butane and / or isobutane.
    [0012] According to one embodiment of the invention, the gaseous reaction mixture comprising (meth) acrylic acid obtained by gas phase oxidation of a precursor of (meth) acrylic acid comprises carbon of renewable origin. According to one embodiment of the invention, the (meth) acrylic acid precursor is derived from glycerol, 3-hydroxypropionic acid or 2-hydroxypropanoic acid (lactic acid).
    [0013] According to a preferred embodiment of the invention, the gaseous reaction mixture comprises acrylic acid derived from propylene obtained by a two-stage oxidation process.
    [0014] The process according to the invention produces a flow of (meth) acrylic acid without producing aqueous discharges, and does not require the use of an azeotropic solvent to remove water from the process. The process according to the invention also contributes to limiting losses of (meth) acrylic acid at the top of the dehydration column.
    [0015] The present invention also relates to an installation for recovering (meth) acrylic acid, adapted to implement the method according to the invention. The plant according to the invention comprises at least: a) a dehydration column; b) a finishing column fluidly connected at the bottom of said dewatering column; c) at least one dry vacuum pump condensation system fluidly connected to the top of said finishing column. d) optionally an E230 / 300 dry vacuum pump condensing system fluidly connected laterally to said finishing column.
    [0016] By "fluidic connection" or "fluidically connected", it is meant to indicate that there is connection by a system of pipes capable of conveying a flow of material. This connection system can include valves, taps, heat exchangers or compressors.
    [0017] According to certain particular embodiments, the invention also has one or, preferably, several of the advantageous characteristics listed below: the dry vacuum pump condensation system comprises at least one condenser fluidly connected to a vacuum pump; dry; The dry vacuum pump condensation system comprises several condensers; the dry vacuum pump condensation system may optionally comprise a liquid separator, one or more flame arrestors, one or more filters, sealing and isolation systems, a pump or a combination of dry booster pumps, such as Roots pumps; The finishing column is fluidly connected to a dry vacuum pump condensation system at the top of the column or at the top of the column and laterally to the column. the dry vacuum pump condensation system is fluidly connected to the finishing column for condensing a distilled stream at the top of the finishing column, or for condensing a stream withdrawn laterally from the finishing column, or a mixture of these two streams. Another object of the invention is a process for producing (meth) acrylic acid comprising at least the following steps: A) at least one (meth) acrylic acid precursor is subjected to gas phase oxidation to form a gaseous reaction mixture comprising (meth) acrylic acid; B) the gaseous reaction mixture is cooled; C) the cooled gaseous reaction mixture is subjected to the (meth) acrylic acid recovery process as previously defined. The present invention makes it possible to overcome the drawbacks of the state of the art related to the implementation of a solventless recovery / purification process that requires obtaining a purified (meth) acrylic acid. Other features and advantages of the invention will become more apparent on reading the detailed description which follows, with reference to FIGS. 1 to 4, which show: FIG. 1: diagram of an acrylic acid production process illustrating the recovery / purification process without solvent according to the invention. - Figure 2: installation adapted to the implementation of the recovery method illustrating an embodiment of the invention. Figure 3: Installation of the prior art including a liquid ring pump condensing system. - Figure 4: installation of the prior art with a condensing system incorporating steam ejectors. DETAILED DESCRIPTION OF THE INVENTION The invention is based on the integration of a dry vacuum pump fluidly connected to a condenser forming a dry vacuum pump condensation system in a process for producing (meth) acid acrylic.
    [0018] In Figure 1, there is shown a reactor R producing a gaseous reaction mixture comprising (meth) acrylic acid obtained by gas phase oxidation of a precursor of (meth) acrylic acid. The gaseous reaction mixture comprising a mass ratio water / acid (meth) acrylic generally between 0.3 and 2 may be previously cooled before being subjected to dehydration according to step i) of the process according to the invention in a first column C100 called dehydration column. The dehydration column leads to a head stream 14, a part of which is condensed and returned to the dehydration column in the form of reflux 13 to absorb the (meth) acrylic acid, the other part 19 comprising the incondensable light compounds being generally sent partially or totally to a purification device or partly recycled to other stages of the process for producing (meth) acrylic acid, preferably in a stage situated upstream of the reactor R. According to one embodiment, the reactor R is a set of 2 reactors in series or comprises at least 2 reaction zones in series, the first reactor or the first reaction zone being used for the synthesis of the (meth) acrylic acid precursor. According to one embodiment, the entire head flow 14 of the dehydration column is sent into the head condenser.
    [0019] The purpose of step i) is to remove in a head flow most of the water present in the reaction mixture, but also the incondensable light compounds and condensable light compounds. The dehydration column operates, at least partially, as a distillation column. It is supplied in its lower part by the reaction mixture 10. It generates a flow of the head 14 comprising most of the water and light compounds, this head flow being depleted in (meth) acrylic acid, and a stream foot 11 comprising most of the (meth) acrylic acid with heavy byproducts. Advantageously, the dehydration column operates at atmospheric pressure or slightly higher, up to 1.5 i05 Pa.
    [0020] Advantageously, the temperature in the upper part of the dehydration column is at least 40 ° C, preferably between 40 ° C and 80 ° C. The temperature of the foot flow of the dewatering column preferably does not exceed 120 ° C. According to the invention, most of the water present in the gaseous reaction mixture comprising the (meth) acrylic acid is removed during step i) without there being excessive loss of water. acrylic acid in the overhead stream 19. No azeotropic solvent is added to the dehydration column.
    [0021] The water mass content in the foot stream of the dewatering column is generally less than 10%, preferably less than 7%. According to step ii) of the process according to the invention, the foot flow 11 of the dehydration column is sent at least partly (stream 15) at the head of a second distillation column, called finishing column, or purification column, C200, in which a head flow 17 and a foot flow 20 are separated. Alternatively, the foot flow of the dehydration column is sent at least partly between the head and the side discharge of the purification column.
    [0022] The foot flow of the dewatering column may pass partly into an intermediate tray before entering the purification column. According to one embodiment, a part 12 of the liquid foot stream 11 of the dehydration column is sent by a pump P110 in a heat exchanger E110, which may be a heater or a cooler and reinjected into the dehydration column, so as to constitute a foot loop. Preferably, the portion 12 of the foot flow is reinjected between the feed of the reaction gas mixture and the dehydration head of the column. The remainder (stream 15) of the liquid stream 11 is sent by the same pump P110 feeding the finishing column (or purification) C200.
    [0023] The dewatering column and the finishing column may be of various configurations, for example loose or structured packing column type or tray columns. The dehydration column generally comprises 5 to 50 theoretical plates, preferably 20 to 30 theoretical plates; the finishing column generally comprises from 5 to 30 theoretical plates, preferably from 8 to 20 theoretical plates. The choice of the type of internals in the columns and the choice of ancillary equipment such as heat exchangers, condensers, pumps, inlet and outlets of the fluids will be easily determined according to the considerations known to those skilled in the art. The finishing column (or purification) is a distillation column associated with a reboiler and a condenser. The temperature and pressure in the purification column are not critical, and can be determined in accordance with known distillation methods of the state of the art. Preferably, however, the purification column operates at a pressure below atmospheric pressure, allowing operation at relatively low temperatures, thus avoiding polymerization of the unsaturated products present, and minimizing the formation of heavy by-products. Advantageously, the purification column operates at a pressure ranging from 5 l (Pa to approximately 60 l (Pa, the head flow temperature being advantageously between 40 ° C. and approximately 90 ° C., and the temperature of the foot flow ranging from 60 ° C to 120 ° C. According to the recovery method of the invention, the top gas stream 17 of the finishing column C200 is sent at least partly, preferably wholly, in a system 51 of dry vacuum pump condensation, shown in FIG. 1 by the assembly constituted by the condenser E220 and the dry vacuum pump 300. The condensed liquid 18 mainly containing light compounds, in particular water and acetic acid, as well as the (meth) acrylic acid is advantageously recycled via a pump P220, in the dehydration column C100.The non-condensed vent 22 at the outlet of the condenser E220 is introduced into the dry pump 300, before being eliminated under the for The use of such a system 51 incorporating a dry vacuum pump provides a pressure below atmospheric pressure in the finishing column, thus making it possible to eliminate the compounds at reduced temperature. residual light from the previous dehydration stage of the reaction mixture comprising (meth) acrylic acid. No aqueous effluent is produced by the dry vacuum pump condensation system. Examples of dry vacuum piston pumps are described for example in US 2005/260085 or US 5,921,755. The dry vacuum pumps may also be composed for example of a cylindrical body in which a rotor rotates in an eccentric position, with notches into which are inserted pallets for sucking a gas stream. Any other type of configuration can be used as a dry vacuum pump. The term "dry" indicates that no liquid flow, such as a lubricating oil or water, is in contact with the gas stream feeding the pump. As examples of dry vacuum pumps, mention may be made, without this list being limiting, of dry mechanical pumps with screws, bellows, spiral (scroll pumps), rotary piston, rotary lobe, diaphragm without oil, for example dry vacuum screw pumps marketed by Edwards, or pumps rotors, marketed by the company Sihi. These pumps create a primary vacuum which can if necessary be supplemented by other dry vacuum pumps, such as "Roots" booster dry pumps.
    [0024] Advantageously, the vacuum obtained in the finishing column can be modulated according to the operating speed of the dry vacuum pump. A flow of (meth) acrylic acid 16 is recovered by side withdrawal from the finishing column (step iii), at a lateral level preferably below the feed of said column. The product stream 16 withdrawn may be a liquid stream or a gas stream. The stream 16 withdrawn laterally corresponds to a grade of (meth) acrylic acid technique. It generally consists of (meth) acrylic acid with a purity greater than 98%, preferably greater than 99%. Preferably, it contains less than 1.5%, preferably less than 0.5%, more preferably less than 0.2% by weight of acetic acid, and less than 1%, preferably less than 0.5%. more particularly, less than 0.3% by weight of water. The stream 16 may be further subjected to a distillation purification, optionally coupled with a crystallization treatment. According to a preferred embodiment of the invention, at least a portion of the flow of purified (meth) acrylic acid 16 withdrawn laterally is subjected to a dry vacuum pump condensation system which may include the dry vacuum pump 300 used at the top of the finishing column.
    [0025] According to one embodiment, the stream 16 is subjected to condensation in a condenser E230 and the gas stream 23 is sent into the vacuum pump 300. According to a particular embodiment of the invention, as represented in FIG. , the gas stream 22, optionally mixed with the stream 23, supplying the dry vacuum pump, passes beforehand into a liquid separator device 310, for separating traces of residual liquid, rich in light compounds, in particular water and acid acetic acid, as well as residual (meth) acrylic acid. Preferably, this liquid stream will be recycled to the dehydration column, for example in a mixture with the flow 18 supplying the pump P220. According to other embodiments, the gas leaving the dry vacuum pump 30 passes through various elements, such as those described above, in particular at least one flame arrester 320, and a dry auxiliary pump 330, before being finally sent to an incinerator. The condensate 18, formed by the dry vacuum pump condensation system, is advantageously returned partly or wholly to the dehydration column, between the foot and the top of the column and preferably above the feed. of the reaction gas mixture. According to one embodiment, it is mixed with the flow 12 of the foot loop of the dewatering column, as shown in FIG. 1. Optionally, the stream 18 can pass through an intermediate storage tank before recycling into the dewatering loop. foot of dehydration column.
    [0026] A flow of (meth) acrylic acid comprising most of the heavy byproducts, including Michael adducts as well as polymerization inhibitors, is recovered at the bottom of the finish column (step iii). The bottom flow of the finishing column corresponds to a crude (meth) acrylic acid grade which can be used directly as raw material in an acrylic ester production unit by direct esterification, or optionally after a step of thermal decomposition of Michael addition derivatives releasing (meth) acrylic acid. Alternatively, the bottom stream can be purified in a third distillation column to obtain a technical grade (meth) acrylic acid.
    [0027] Advantageously, the stream 16 of laterally withdrawn product and the bottom stream of the finishing column are recovered in a weight ratio of from 99: 1 to 25:75, preferably from 98: 2 to 50:50. Inhibitors The polymerization process may be introduced at various locations in the plant for carrying out the process of the invention, in particular in the top stream of the dehydration column at the level of the condenser, or in the top stream of the column. purification at the condenser associated with said column, or in the stream of purified product withdrawn laterally from the purification column, optionally after condensation in the case where the withdrawn stream is in gaseous form. The polymerization inhibitors are selected from compounds which inhibit the polymerization reaction of (meth) acrylic acid and are added in a sufficient amount known to those skilled in the art to avoid or reduce the polymerization of the acid ( meth) acrylic acid. As examples of usable compounds, mention may be made of phenothiazine, hydroquinone, 2,2,6,6-tetramethyl-1-piperidinyloxy (Tempo) or one of its derivatives such as 4-hydroxy-Tempo, the salts soluble copper salts, the soluble manganese salts, alone or as a mixture, optionally in solution in water, in (meth) acrylic acid or in a mixture of water and (meth) acrylic acid. According to one embodiment of the invention, the nature of the inhibitor varies according to the place where it is injected. According to one embodiment of the invention, air or a gas comprising oxygen is introduced, for example in the feet of the dehydration and purification columns, in the reboilers of the columns, in the recirculation loop. at the bottom of the dehydration column or at the side withdrawal of the purification column or in the condensers. The process of the invention provides directly, in lateral withdrawal from the finishing column, a quality of (meth) acrylic acid which corresponds to a grade of (meth) acrylic acid, which can then be sent to a unit of purification, for example by crystallization, to obtain a quality of (meth) acrylic acid called "glacial". It also provides at the bottom of the finishing column, a quality of crude (meth) acrylic acid which can then be purified or heat treated to obtain a grade of (meth) acrylic acid. The plant according to the invention adapted to implement the process of recovery / purification of (meth) acrylic acid as described, comprises at least: a) a dehydration column C100; B) a finishing column C200 fluidically connected at the bottom of said dewatering column; c) at least one dry vacuum pump condensing system E220 / 300, fluidly connected at the top of said finishing column. d) optionally an E230 / 300 dry vacuum pump condensing system fluidly connected laterally to said finishing column. Another subject of the invention relates to a process for producing (meth) acrylic acid comprising at least the following steps: A) the gas phase oxidation is subjected to at least one (meth) acrylic acid precursor for forming a gaseous reaction mixture comprising (meth) acrylic acid; B) the gaseous reaction mixture is cooled; C) the cooled gaseous reaction mixture is subjected to the (meth) acrylic acid recovery process as defined above.
    [0028] The precursor of the (meth) acrylic acid may be acrolein or methacrolein, and may be derived from renewable raw material thereby producing biosourced (meth) acrylic acid. Preferably, (meth) acrylic acid is acrylic acid and the precursor of acrylic acid is acrolein obtained by catalytic oxidation of propylene.
    [0029] The oxidation reaction of step A), performed according to the state of the art, generally provides a gaseous reaction mixture, superheated at a temperature above 280 ° C. This mixture is advantageously cooled in a stage B), in particular up to a temperature below 250.degree. C., preferably below 190.degree. C., to be subjected according to stage C) to the acid recovery process ( meth) acrylic without the use of azeotropic solvent including a dry vacuum pump condensation system. It can be cooled directly in the dewatering column, or can be cooled using a heat exchanger located upstream of the dewatering column.
    [0030] Although the use of the dry vacuum pump condensation system is described in the present invention in a process for producing (meth) acrylic acid including a solventless purification process with two distillation columns, the condensation system The dry vacuum pump can also be used in other processes that produce a gaseous reaction mixture, in order to reduce the amount of water and steam used, and thus reduce the amount of aqueous effluents discharged. The invention will now be illustrated by the following examples, which are not intended to limit the scope of the invention, defined by the appended claims.
    [0031] EXPERIMENTAL PART Example 1 (according to the invention) Simulations using ASPEN software were used to illustrate the process according to the invention. Referring to Figure 1, in a process for the continuous production of acrylic acid from propylene, a reaction mixture was subjected to the recovery / purification process according to the invention. In this process, 11,000 kg / h of technical acrylic acid is produced (stream 16), having a purity of 99.8%. The main impurities are acetic acid (0.05%), propionic acid (0.021%), furfural (0.014%), benzaldehyde (0.008%) and maleic anhydride (0.037%). The gas stream 22 (67.6 kg / h) from the condenser E220 at the top of the finishing column C200 was subjected to a dry vacuum pump 300. This pump 35 provides a pressure of 12 kPa at the top of the column C200 . A stream 23 (7.3 kg / h) from the condenser E230 placed at the side outlet of the technical acrylic acid stream was sent at the same time to the dry vacuum pump 300.
    [0032] The main constituents of the incoming streams 22 and 23, as well as the composition of the outgoing gas flow, expressed in hourly mass flow (kg / h), are collated in Table 1. No aqueous effluent is produced according to this system. .
    [0033] At the outlet of the dry vacuum pump, only an ultimate gaseous effluent (74.9 kg / h) is emitted, which is easily removed by methods known to those skilled in the art, for example by oxidation. thermal or catalytic. The loss of acrylic acid in stream 19 cooled to 57 ° C is 0.69%, giving an acrylic acid recovery yield of 99.31%.
    [0034] Table 1 Mass flow rate kg / h Flux 22 Flux 23 Gaseous effluent flow N2 4,823E + 00 0,000E + 00 4,823E + 00 02 3,032E + 01 6,134E + 00 3,646E + 01 CO 2,441E-02 0,000E + 00 2,441E-02 CO2 1,431E-01 0,000E + 00 1,431E-01 propylene 6,118E-01 0,000E + 00 6,118E-01 propane 1,990E-01 0,000E + 00 1,990E-01 formaldehyde 7,109E-01 0,000 E + 00 7,109E-01 acetaldehyde 6,608E-03 0,000E + 00 6,608E-03 acrolein 3,537E-01 0,000E + 00 3,537E-01H20 8,108E + 00 2,316E-09 8,108E + 00 Acetic acid 4,870E +00 1,441E-03 4,871E + 00 Acrylic acid 1,739E + 01 1,181E + 00 1,857E + 01 Acid 1,941E-03 2,357E-04 2,177E-03 propionic furfural 6,446E-04 9,564E-05 7,402E- 04 benzaldehyde 4,463E-04 3,563E-05 4,820E-04 Maleic anhydride 5,412E-04 7,153E-05 6,127E-04 TOTAL 67,571 7,316 74,887 Examples 2 and 3 (comparative) 15 For comparison, the same flows 22 and 23 were respectively subjected to a liquid ring pump (Example 2, Figure 3) replacing the dry vacuum pump, and a system integrating eject steamers (Example 3, Figure 4). In particular, Example 3 involves a steam ejector vacuum generator technology described in US 6,677,482 or US 7,288,169.
    [0035] In FIG. 3, there is shown a system S2 incorporating a liquid ring pump P240 fed by a flow of water 24. The flow rate of the flow 24 introduced into the pump to ensure a pressure of 12 kPa is 1000 kg / h. . This system S2 comprises a pump P240, an exchanger E240 and a condensate collecting container R. The pump P240 is supplied on the one hand by the gas streams 22 and 23 coming from the column C200 and on the other hand by the flow The main role of this aqueous stream is to constitute a liquid seal necessary for the generation of the vacuum in the pump and to ensure the renewal of the liquid by purging condensed impurities. The heat released by the pump is eliminated by cooling the condensed flow through the exchanger. The outflow of the pump is partly liquid and partly gaseous. The two phases are separated in the container R and part of the liquid phase (essentially aqueous) is recirculated to the pump P240 after cooling in the exchanger E240. This system S2 thus produces at the outlet a gas flow 25 (43.2 kg / h), but also a liquid effluent 26 in large quantity (1031.7 kg / h). This stream 26, essentially aqueous, contains organic compounds in solution at high concentrations (mainly 1.8% of acrylic acid, 0.5% of acetic acid), which renders it unfit for rejection without further treatment of purification. FIG. 4 shows a system S3 incorporating two ejectors in series P240 and P250 fed respectively with 400 kg / h of water vapor (stream 27) and 600 kg / h of water vapor (stream 28), in order to ensure a pressure of 12 kPa at the top of the column C200. This S3 system comprises the 2 pumps (ejectors) connected in series which are fed by pressure steam of 1500 kPa and 3 condensers. The first ejector P240 is supplied on the one hand by the gas streams 22 and 23 from the column C200 and on the other hand by the flow of water vapor under pressure.
    [0036] The gas stream exiting at a temperature of 144 ° C. is cooled to a temperature of 42 ° C. in a first condenser E240. The liquid condensate 29 is sent to a condensate collection vessel R and the uncondensed gas vents 30 are fed to the 2nd ejector P250. At the outlet of this ejector, the gaseous flow at 162 ° C. is cooled to a temperature of 42 ° C. in the condenser E250. The condensed liquid flow 31 is sent into the receiver R. The uncondensed vents 32 in this 2nd condenser are cooled to 15 ° C in the third condenser E260, producing a third liquid condensate collected in the tank R. The flow Non-condensed gas in this 3rd condenser is removed. This system S3 thus produces at the outlet a gas flow 25 (42.8 kg / h), but also an aqueous effluent 26 in large quantity (1032.1 kg / h). This aqueous stream 26 contains organic compounds in solution, at high concentrations (mainly 1.8% acrylic acid, 0.5% acetic acid), which make it unfit for rejection without further purification treatment. The main constituents of the gas stream 25 and the aqueous stream 26 at the outlet of the systems S2 and S3 are shown in Table 2.
    [0037] Table 2 Example 1 Example 2 (comp) Example 3 (comp) Mass flow kg / h Flow Gas stream Aqueous stream Gas stream Aqueous gas stream 25 25 26 25 26 N2 4,823E + 00 4,820E + 00 2,845E-03 4,821E +00 1,453E-03 02 3,646E + 01 3,642E + 01 3,737E-02 3,644E + 01 1,931E-02 CO 2,441E-02 2,439E-02 1,782E-05 2,439E-02 1,207E-05 CO2 1,431 E-01 1,376E-01 5,575E-03 1,410E-01 2,102E-03 propylene 6,118E-01 6,076E-01 4,248E-03 6,107E-01 1,148E-03 propane 1,990E-01 1,987E-01 2,888 E-04 1,989E-01 1,124E-04 formaldehyde 7,109E-01 9,219E-04 7,099E-01 5,115E-05 7,108E-01 acetaldehyde 6,608E-03 8,909E-04 5,717E-03 1,830E-03 4,778 E-03 acrolein 3,537E-01 9,535E-02 2,584E-01 1,591E-01 1,946E-01 H20 8,108E + 00 8,758E-01 1,007E + 03 4,162E-01 1,008E + 03 Acetic acid 4,871E + 00 2,005E-03 4,869E + 00 1,634E-05 4,871E + 00 Acid 1,857E + 01 7,855E-03 1,857E + 01 6,686E-05 1,857E + 01 Acrylic Acid 2,177E-03 1,239E-06 2,175E -03 1,878E-08 2,177E-03 furfural propionic 7,402E-04 4,273E-06 7,360E-04 2,027E-06 7,382E-04 Benzaldehyde e 4,820E-04 3,393E-05 4,480E-04 5,944E-05 4,225E-04 Maleic anhydride 6,127E-04 5,197E-08 6,127E-04 2,376E-11 6,127E-04 TOTAL 74,887 43,191 1031,697 42,811 1032,075 Conventional vacuum systems involving a liquid ring pump, or steam jet ejectors generate a large amount of aqueous effluent. This effluent contains organic impurities and must be treated.
    [0038] EXAMPLE 4 To avoid expensive treatment of the aqueous flow from the liquid ring pump (Example 2) or the ejector system (Example 3), and recover a part of the acrylic acid contained in these streams, it can Consideration should be given to recycling these streams in the solventless purification process. A simulation of the solvent-free purification process was carried out using the ASPEN software, incorporating a recycling of the condensed aqueous flux 26 in Example 3 (ejectors in series), mixed in the stream 18 returned to the column of 10 dehydration C100 (see Figure 1). Under these conditions, contrary to the desired objective, it is observed that the recycling of this aqueous stream (1032 kg / h) causes a significant loss of acrylic acid at the top of the column C100 condensation. The loss of acrylic acid in stream 19 cooled to 61 ° C is 1.74%, giving an acrylic acid recovery yield of 98.26%.
    权利要求:
    Claims (12)
    [0001]
    REVENDICATIONS1. Process for recovering (meth) acrylic acid without the use of azeotropic solvent from a gaseous reaction mixture comprising (meth) acrylic acid obtained by gas phase oxidation of a precursor of (meth) acid acrylic, comprising at least the following steps: i) the gaseous reaction mixture is subjected to dehydration without using an azeotropic solvent in a first column called dehydration column, leading to a flow of head at least a part of which is condensed and returned to the dehydration column as reflux, and a foot flow; ii) at least partially submitting the dehydration column foot stream to a distillation at a pressure below atmospheric pressure in a second column called finishing column, leading to a flow of head, and a foot flow containing heavy compounds; iii) recovering a flow of (meth) acrylic acid by lateral withdrawal of the finishing column, and / or at the bottom of the finishing column; said method being characterized in that the top flow of the finishing column is at least partly subjected to a dry vacuum pump condensing system, forming a condensate which is returned to the dewatering column, and a gaseous effluent ultimate.
    [0002]
    2. Method according to claim 1 characterized in that the dry vacuum pump condensation system comprises at least one condenser and a dry vacuum pump.
    [0003]
    3. Method according to claim 1 or 2, characterized in that the dry vacuum pump condensation system further comprises a liquid separator, or one or more flame arrestors, or one or more filters, or sealing systems. and isolation, or a pump or combination of dry booster pumps.
    [0004]
    4. Method according to any one of the preceding claims characterized in that at least a portion of the flow of (meth) acrylic acid withdrawn laterally is subjected to a dry vacuum pump condensation system, identical or different from that used for the top flow of the finishing column. 25 30 35
    [0005]
    5. Process according to any one of the preceding claims, characterized in that the precursor of (meth) acrylic acid is acrolein, obtained by oxidation of propylene or by oxyhydrogenation of propane.
    [0006]
    6. Process according to any one of Claims 1 to 4, characterized in that the precursor of the (meth) acrylic acid is methacrolein obtained by oxidation of isobutylene and / or tert-butanol or from oxidationhydrogenation. butane and / or isobutane.
    [0007]
    7. Process according to any one of Claims 1 to 4, characterized in that the precursor of the (meth) acrylic acid comprises carbon of renewable origin.
    [0008]
    8. Process according to claim 7, characterized in that the precursor of the (meth) acrylic acid is derived from glycerol, 3-hydroxypropionic acid or 2-hydroxypropanoic acid. 15
    [0009]
    9. Method according to any one of the preceding claims characterized in that it further comprises at least one step of purifying the flow of (meth) acrylic acid recovered in step iii).
    [0010]
    A process for producing (meth) acrylic acid comprising at least the following steps: A) at least one (meth) acrylic acid precursor is subjected to gas phase oxidation to form a gaseous reaction mixture comprising (meth) acrylic acid; B) the gaseous reaction mixture is cooled; C) the cooled gaseous reaction mixture is subjected to the (meth) acrylic acid recovery process as defined in any one of claims 1 to 9.
    [0011]
    11. The method of claim 10 characterized in that the (meth) acrylic acid is acrylic acid and the precursor of acrylic acid is acrolein obtained by catalytic oxidation of propylene.
    [0012]
    12. Installation for recovering (meth) acrylic acid without using an azeotropic solvent comprising at least: a) a C100 dehydration column; B) a finishing column C200 fluidically connected at the bottom of said dewatering column; c) at least one E220 / 300 dry vacuum pump condensation system, fluidically connected to the top of said finishing column. D) optionally an E230 / 300 dry vacuum pump condensation system fluidly connected laterally to said finishing column.
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    同族专利:
    公开号 | 公开日
    MX2017011048A|2017-11-10|
    EP3268345B1|2019-04-24|
    US20180079706A1|2018-03-22|
    WO2016142608A1|2016-09-15|
    FR3033558B1|2017-02-24|
    EP3268345A1|2018-01-17|
    US10239816B2|2019-03-26|
    SG11201707364UA|2017-10-30|
    KR20170128262A|2017-11-22|
    CN107428659A|2017-12-01|
    JP2018507893A|2018-03-22|
    CN107428659B|2020-10-27|
    TW201708178A|2017-03-01|
    JP6716597B2|2020-07-01|
    BR112017015935A2|2018-03-27|
    BR112017015935B1|2021-07-27|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US7288169B2|2001-08-22|2007-10-30|Mitsubishi Chemical Corporation|Distillation apparatus for readily polymerizable compound|
    US5921755A|1997-04-21|1999-07-13|Dry Vacuum Technologies, Inc.|Dry vacuum pump|
    JP3948855B2|1999-06-10|2007-07-25|株式会社日本触媒|Method for producing acrylic acid|
    JP2001213839A|2000-02-03|2001-08-07|Nippon Shokubai Co Ltd|Method for producing acrylic acid|
    JP3957298B2|2003-06-05|2007-08-15|株式会社日本触媒|Acrylic acid production method|
    JP4715106B2|2004-04-01|2011-07-06|三菱化学株式会社|Method for producing acrylic acid derivative|
    DE102004024562A1|2004-05-18|2005-12-15|Pfeiffer Vacuum Gmbh|Dry running piston vacuum pump|
    JP5009634B2|2006-01-31|2012-08-22|株式会社荏原製作所|Vacuum pump unit|
    JP5199260B2|2006-09-15|2013-05-15|アルケマインコーポレイティド|Acrylic acid production method|
    CN200978804Y|2006-11-02|2007-11-21|瞿斌|All-dry type special rotary vane vacuum pump|
    CN201723446U|2010-06-24|2011-01-26|任利民|Dry vacuum micro-system|FR3049601B1|2016-03-29|2018-03-09|Arkema France|IMPROVED PROCESS FOR THE PRODUCTION OFACRYLIC ACID|
    CN110394017A|2019-07-19|2019-11-01|江门谦信化工发展有限公司|A kind of vacuum system produced applied to acrylic acid and esters of acrylic acid|
    CN111467904A|2020-04-01|2020-07-31|江苏格里克真空技术有限公司|Boosting condensation separation adsorption filtering device|
    FR3108906B1|2020-04-06|2022-03-04|Arkema France|ACRYLIC ACID PURIFICATION PROCESS|
    法律状态:
    2016-02-08| PLFP| Fee payment|Year of fee payment: 2 |
    2016-09-16| PLSC| Publication of the preliminary search report|Effective date: 20160916 |
    2017-02-13| PLFP| Fee payment|Year of fee payment: 3 |
    2018-02-23| PLFP| Fee payment|Year of fee payment: 4 |
    2020-02-14| PLFP| Fee payment|Year of fee payment: 6 |
    2021-12-10| ST| Notification of lapse|Effective date: 20211105 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1552049A|FR3033558B1|2015-03-12|2015-03-12|IMPROVED PROCESS FOR THE PRODUCTION OFACRYLIC ACID|FR1552049A| FR3033558B1|2015-03-12|2015-03-12|IMPROVED PROCESS FOR THE PRODUCTION OFACRYLIC ACID|
    BR112017015935-0A| BR112017015935B1|2015-03-12|2016-03-04|IMPROVED PROCESS TO PRODUCE ACRYLIC ACID AND INSTALLATION FOR RECOVERY|
    KR1020177024808A| KR20170128262A|2015-03-12|2016-03-04|Improved process for producing acrylic acid|
    PCT/FR2016/050501| WO2016142608A1|2015-03-12|2016-03-04|Improved process for producing acrylic acid|
    CN201680014926.3A| CN107428659B|2015-03-12|2016-03-04|Improved process for producingacrylic acid|
    MX2017011048A| MX2017011048A|2015-03-12|2016-03-04|Improved process for producing acrylic acid.|
    US15/556,308| US10239816B2|2015-03-12|2016-03-04|Process for producing acrylic acid|
    JP2017548028A| JP6716597B2|2015-03-12|2016-03-04|Improved method for producing acrylic acid|
    SG11201707364UA| SG11201707364UA|2015-03-12|2016-03-04|Improved process for producing acrylic acid|
    EP16712960.0A| EP3268345B1|2015-03-12|2016-03-04|Improved process for producing acrylic acid|
    TW105107054A| TW201708178A|2015-03-12|2016-03-08|Improved process for producing acrylic acid|
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