EP2401045A1 - Procédé de traitement par distillation d'un mélange méthanol/eau et procédé de préparation de méthylates alcalins - Google Patents

Procédé de traitement par distillation d'un mélange méthanol/eau et procédé de préparation de méthylates alcalins

Info

Publication number
EP2401045A1
EP2401045A1 EP10703905A EP10703905A EP2401045A1 EP 2401045 A1 EP2401045 A1 EP 2401045A1 EP 10703905 A EP10703905 A EP 10703905A EP 10703905 A EP10703905 A EP 10703905A EP 2401045 A1 EP2401045 A1 EP 2401045A1
Authority
EP
European Patent Office
Prior art keywords
methanol
column
evaporator
distillation column
water mixture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP10703905A
Other languages
German (de)
English (en)
Inventor
Gerd Kaibel
Tilmann Sirch
Raimund Felder
Josef Guth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Priority to EP10703905A priority Critical patent/EP2401045A1/fr
Publication of EP2401045A1 publication Critical patent/EP2401045A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/28—Evaporating with vapour compression
    • B01D1/284—Special features relating to the compressed vapour
    • B01D1/2856—The compressed vapour is used for heating a reboiler or a heat exchanger outside an evaporator
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/68—Preparation of metal alcoholates
    • C07C29/70—Preparation of metal alcoholates by converting hydroxy groups to O-metal groups
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • Di e invention relates to a process for the distillative workup of a methanol / water mixture. Furthermore, the invention relates to a process for the preparation of Alkalimethanolaten in a reaction column, wherein the reaction column methanol and lye is added, at the lower end of the reaction column in methanol solubilized alkali is removed and at the upper end of the reaction column, a methanol / water mixture is removed , The methanol / water mixture is worked up by the process for distillative work-up.
  • a mixture containing methanol and water is obtained, for example, in the preparation of alkali metal methylates from aqueous alkali metal hydroxide, optionally mixed with methanol, and methanol.
  • a process for the preparation of alkali metal methoxides is described, for example, in EP-A 1 242 345.
  • the reaction is carried out in a reaction column, which at the top is fed with an aqueous, optionally methanol-mixed, alkali-leach stream and methanol in the lower region.
  • a water-containing methanol stream escapes. This is worked up in a rectification column.
  • the methanol and water-containing stream is the distillation column, in which the workup is carried out as a side stream, preferably in the form of vapor.
  • a separation of the methanol / water mixture into a substantially methanol-containing stream which is withdrawn at the top of the column, and a substantially water-containing stream, which is withdrawn at the bottom of the column.
  • at least part of the substantially water-containing stream withdrawn at the bottom of the column is evaporated in an evaporator.
  • the evaporator is usually heated for this purpose with heating steam.
  • heating steam first the generation of the heating steam is necessary.
  • the methanol recovered at the top of the distillation column is partly condensed in a condenser and returned to the column, the remainder being fed as feed into the reaction column.
  • the object of the present invention is to provide a process for the treatment of a methanol / water mixture, which can be operated with a reduced compared to the known methods need to be supplied to heating steam.
  • the object is achieved by a process for the distillative workup of a methanol / water mixture, comprising the following steps:
  • substantially methanol-containing means a proportion of methanol of at least 99% by weight, preferably of at least 99.9% by weight and in particular of at least 99.99% by weight.
  • Substantially containing water means a proportion of water in the stream of at least 95 wt .-%, preferably of at least 99 wt .-% and in particular of at least 99.99 wt .-%.
  • the removal of the vapor stream at the top of the distillation column means in the context of the present invention that the vapor stream is removed as top stream or as a side draw above the internals in the distillation column.
  • the removal of the substantially water-containing bottoms stream at the bottom of the column is usually carried out at the bottom of the column, but the removal can also take place via a side draw in the bottom.
  • distillation column Any distillation column known to those skilled in the art can be used as the distillation column.
  • Suitable internals are, for example, trays, unstructured packs or structured packings. As trays usually bubble trays, trays, valve trays, tunnel trays or slot floors are used. Unstructured packages are generally packed beds. Suitable packing elements are customarily as Raschig rings, Pall rings, Berl saddles or Intalox ® saddles used. Structured packings are sold for example under the trade name Mellapack ® Sulzer.
  • suitable internals are known in the art and can also be used.
  • Preferred internals have a low specific pressure loss per theoretical separation stage.
  • structured packing and packing have a much lower pressure drop per theoretical plate than plates. This has the advantage that the pressure loss in the distillation column remains as low as possible and thus the mechanical performance of the compressor and the temperature of the methanol / water mixture to be vaporized remain low.
  • structured packings or unstructured packs are contained in the column, they may be divided or there may be a continuous packing. Usually, however, at least two packs are provided, one pack above the feed point of the methanol / water mixture and one pack below the feed point of the methanol / water mixture. If an unstructured packing is used, for example a packed body, the fillers are usually located on a suitable sieve bottom or grid floor.
  • the evaporator which is heated with the compressed part of the substantially methanol-containing vapor stream, an intermediate evaporator.
  • the evaporator is arranged above the bottom of the distillation column. This has the advantage that the temperature of the methanol / water mixture to be evaporated, which is taken from the distillation column and passed through the evaporator, has a lower evaporation temperature has as the withdrawn at the bottom of the column, substantially water-containing bottom stream.
  • the vapor stream must therefore be compressed less strongly, which makes a lower energy supply necessary for compression.
  • the evaporator to which the compressed vapor stream is added as heating steam an intermediate evaporator.
  • the evaporator is usually arranged outside the distillation column. About a deduction from the column to be evaporated in the evaporator methanol / water mixture is withdrawn and fed to the evaporator. Via an inlet, the vaporized mixture is optionally returned to the distillation column with a residual liquid. If the evaporator is a Swissverdamp- fer, the trigger through which the methanol / water mixture is withdrawn and fed to the evaporator, a side draw and the inlet through which the vaporized methanol / water mixture is fed back to the column, a side feed.
  • the evaporator heats the bottom of the column, at least part of the bottom withdrawal stream is fed to the evaporator, evaporated in the evaporator and returned to the column in the region of the bottom.
  • Suitable evaporators which can be heated with the compressed vapor stream are, for example, natural circulation evaporators, forced circulation evaporators, forced circulation evaporators with expansion, steam boilers, falling film evaporators or thin-film evaporators.
  • a heat exchanger for the evaporator usually a tube bundle or plate apparatus is used in natural circulation evaporators and forced circulation evaporators.
  • the compressed vapor stream can either flow through the tubes and the methanol / water mixture to be evaporated flow around the tubes or flows around the compressed vapor stream flows around the tubes and the methanol / water mixture to be evaporated the pipes.
  • a falling film evaporator In a falling film evaporator, the methanol / water mixture to be evaporated is usually added as a thin film on the inside of a pipe, and the pipe is heated from the outside.
  • a rotor with wipers is additionally provided in a thin-film evaporator, which distributes the liquid to be evaporated on the inner wall of the tube into a thin film.
  • the evaporator which is operated with the compressed vapor stream as heating steam, is an intermediate evaporator
  • the intermediate evaporator is arranged in the stripping section of the distillation column or in the region of the feed point of the methanol / water mixture. Due to the arrangement of the intermediate evaporator in the stripping section of the distillation column or in the region of the feed point of the methanol / water mixture, a predominant part of the heating energy can be introduced through the intermediate evaporator. For example, it is possible to introduce over 80% of the energy via the intermediate evaporator.
  • the intermediate evaporator is preferably arranged and / or designed such that more than 50%, in particular more than 75%, of the total energy required for the distillation is introduced therewith.
  • the intermediate evaporator is arranged such that the distillation column below the intermediate evaporator has from 1 to 50 theoretical plates and above the intermediate evaporator from 1 to 200 theoretical plates. In particular, it is preferred if the distillation column below the intermediate evaporator has 2 to 10 theoretical plates and above the intermediate evaporator 20 to 50 theoretical plates.
  • the side draw stream through which the methanol / water mixture is fed to the intermediate evaporator and the side feed via which the vaporized methanol / water mixture from the evaporator is returned to the distillation column may be positioned between the same trays of the distillation column. However, it is also possible that the side print and the page feed are at different heights.
  • the diameter of the distillation column above the intermediate evaporator is greater than the diameter of the distillation column below the intermediate evaporator.
  • step (c) The compression of the vapor stream in step (c) can be carried out in any manner known to those skilled in the art.
  • the compaction can be carried out in one or more stages.
  • several compressors of the same design or compressors of different types can be used.
  • single-stage compression or multi-stage compression depends on the pressure at which the vapor stream is to be compressed.
  • the pressure difference to be overcome with the compressor is smaller than when using the vapor stream for heating a compressor at the bottom of the distillation column.
  • the larger pressure difference to be overcome can be overcome by additional compressor stages or by a more powerful compressor. Usually, however, additional compressor stages are used.
  • a compressor for compressing the vapor stream is any, known in the art compressor with which can compress gas streams.
  • Suitable compressors are, for example, single-stage or multi-stage turbines, reciprocating compressors, screw compressors, centrifugal compressors or axial compressors.
  • another conventionally heated vaporiser is preferably used, which is arranged at the bottom of the distillation column. If the evaporator heated with the vapor stream is likewise arranged at the bottom of the column, the conventionally heated evaporator can be used, for example, to additionally supply heat during operation of the distillation column. In general, however, the conventionally heated evaporator is used to start the column. When starting the column is still not sufficient vapor available, with which the evaporator can be heated, so that first must be supplied from outside heat. After starting the distillation column takes the amount of vapor that can be removed at the top of the column, and the operation can be switched to the heated with the compressed vapor stream evaporator.
  • the additional, conventionally heated evaporator is used to introduce further heat at the bottom of the column in the distillation column.
  • the conventionally heated evaporator is operated over the entire operating life of the distillation column. Again, to start the column, a larger amount of heat must first be introduced into the distillation column via the conventionally heated evaporator until the intermediate evaporator can be supplied with a sufficiently large vapor stream in order to heat it. Then the amount of heat that is introduced into the distillation column with the conventionally heated evaporator can be reduced.
  • an intermediate evaporator it is also possible to use two conventionally heated evaporators at the bottom of the column. The additional conventionally heated evaporator is then used to start the column and the other conventionally heated evaporator continues to operate during operation of the column.
  • the methanol / water mixture to be separated in the distillation column can be fed in liquid or gaseous form. Preferably, however, the methanol / water mixture is supplied in gaseous form. The addition of the methanol / water mixture is preferably carried out via a side feed.
  • the methanol / water mixture to be separated in the distillation column originates from the preparation of alkali metal methoxides
  • the methanol / water mixture is preferably added in gaseous form to the distillation column.
  • the pressure at which the distillation column is operated is preferably in the range from 0.2 to 10 bar, in particular in the range from 0.5 to 3 bar.
  • a portion of the substantially methanol-containing vapor stream is condensed and returned to the distillation column.
  • the condensed and returned to the distillation column part of the Brü- denströmen can be taken on the one hand the compressed vapor stream, with which the evaporator is heated, or alternatively an additional part, which is not compressed.
  • the portion recycled to the distillation column is preferably expanded to the operating pressure of the distillation column prior to addition to the distillation column.
  • the reflux ratio is preferably at least 0.4, more preferably 0.8 to 1.4.
  • the methanol / water mixture is usually taken from a reaction column for the preparation of the alkali metal methylates as overhead stream.
  • the methanol / water mixture taken off as top stream can then be fed directly into the distillation column.
  • the invention also relates to a process for the preparation of alkali metal methoxides in a reaction column, wherein the reaction column methanol and alkali metal hydroxide are added. At the lower end of the reaction column dissolved in methanol methanolate is taken. At the upper end of the reaction column, a methanol / water mixture is removed, which is then worked up by distillation according to the method described above for working up a methanol / water mixture.
  • the methanol used for the preparation of the alkali metal methoxide can in the inventive embodiment of the method also commercially available methanol with a methanol content of more than 99.8% and a proportion of water of up to
  • the methanol can be fed either in the rectifying section of the distillation column or directly at the top.
  • the optimal feed point depends on the
  • Water content of the methanol used and on the other hand of the desired residual water content in the distillate The higher the water content in the methanol used and the higher the purity requirement in the distillate, the more favorable is a feed to some theoretical plates below the top of the distillation column. Preference is given to up to 20 theoretical plates below the top of the distillation column and in particular 1 to 5 theoretical plates.
  • the reaction column in which the alkali metal methoxide is prepared preferably comprises at least 2, in particular 15 to 40 theoretical plates between the feed point of the alkali metal hydroxide solution and the addition point of the methanol.
  • the reaction column contains internals. Suitable internals are, for example, trays, structured packings or disordered packings. If the reaction column contains trays, bubble trays, valve trays or trays are suitable. If the reaction column contains soils, preference is given to those soils in which a maximum of 5%, preferably less than 1%, of the liquid pass through the respective trays.
  • the constructive measures required to minimize the fürregnens the liquid are familiar to the expert.
  • valve floors for example, particularly tight-fitting valve types are selected. By reducing the number of valves, it is also possible to increase the vapor velocity in the bottom openings up to twice the value that is usually set. When using sieve trays, it is particularly advantageous to reduce the diameter of the bottom openings and to maintain or even increase the number of openings.
  • structured packages are preferred in view of uniform distribution of the liquid.
  • the average ratio of liquid to vapor stream with respect to the liquid must not be exceeded by more than 15%, preferably not more than 3%. This low volume of liquid makes it possible for the capillary effect on the wire mesh to be local
  • the desired characteristic of the liquid distribution can be achieved by the fact that in the edge region of the column cross section adjacent to the column jacket, which corresponds to about 2 to 5% of the total column cross section Fluid Sprinkling over the other cross-sectional areas up to 100%, preferably by 5 to 15%, is reduced.
  • This can be achieved, for example, by the targeted distribution of the drip points of the liquid distributors or their bores with simple means.
  • the preparation of the alkali metal methoxide can be carried out both continuously and discontinuously. Preferably, the preparation is carried out continuously.
  • the alkali metal hydroxide is fed at the top of the reaction column.
  • the reaction column is operated as a pure stripping column.
  • methanol is fed in vapor form.
  • the methanol stream still containing water at the top of the column referred to above as the methanol / water mixture, is worked up by distillation as described above.
  • the methanol obtained in the distillation is then fed back to the reaction column.
  • the amount of methanol used is chosen so that it also serves as a solvent for the resulting alkali metal.
  • the amount of methanol is chosen so that the desired concentration of the alkali metal methoxide solution is present in the bottom of the reaction column.
  • alkali lye Usually used alkali lye are caustic soda and potassium hydroxide.
  • the reaction column is preferably operated without reflux. This means that the entire vapor taken methanol / water mixture is fed to the distillation column.
  • the methanol / water mixture is preferably fed to the distillation column in vapor form.
  • the dimensions at the bottom of the reaction column can be reduced. If a portion of the methanol at the upper end or in the region of the upper end of the reaction column is added in vapor form, only a partial amount of 10 to 70%, preferably from 30 to 50% at the lower end of the reaction column is fed and the remaining portion in a single stream or distributed in several streams, preferably 1 to 10 theoretical plates, more preferably 1 to 3 theoretical plates below the feed point of the alkali added in vapor form.
  • the reaction column is preferably operated at a pressure in the range from 0.5 to 40 bar, preferably in the range from 1 to 5 bar, particularly preferably in the range from 1 to 3 bar, since lower heating powers and smaller amounts of methanol can be realized at a higher pressure ,
  • the distillation column is preferably operated at a pressure chosen to provide the pressure drop between the columns in the case of vapor compression for the methanol / water mixture or, alternatively, that for the reaction column Methanol flow is possible with little effort.
  • the methanol required for the reaction and the dilution of the alkali metal methoxide solutions is added at temperatures up to the boiling point, preferably at room temperature, at the top of the distillation column.
  • a separate feed may be provided for the additional methanol or, on the return of a portion of the methanol taken off at the top of the distillation column, after the condensation, be mixed with it and fed together into the column.
  • the fresh methanol is added to a condensate tank in which the methanol condensed from the vapor stream is collected.
  • the reaction column and the distillation column for working up the methanol / water mixture are housed in a column jacket, wherein the lower portion of the column is divided by a partition wall.
  • the reaction in a part of the column, the reaction is carried out to Alkimimethylat, wherein the caustic is added approximately at the level of the upper end of the dividing wall and the methanol is added in vapor form at the lower end.
  • the above the addition point of the alkali metal resulting methanol / water mixture is then distributed above the dividing wall over the entire column area, which serves as a reinforcing part of the distillation column.
  • the second, separated by the partition lower part of the column is the stripping section of the distillation column.
  • the energy necessary for the distillation is then fed via an evaporator at the lower end of the second part of the column separated by the dividing wall, wherein this evaporator can be conventionally heated or heated with the compressed vapor stream. If the evaporator is conventionally heated, then an intermediate evaporator is additionally provided, which is heated with the compressed vapor stream.
  • FIG. 1 shows a process flow diagram of the process according to the invention for the distillative workup of a methanol / water mixture
  • FIG. 2 shows a process flow diagram for a process for the preparation of alkali metal methoxide in a first embodiment
  • FIG. 3 shows a process flow diagram for a process for the preparation of alkali metal methoxide in a second embodiment
  • FIG. 4 shows a process flow diagram for a process for producing an alkali metal in a third embodiment.
  • FIG. 1 shows a process flow diagram for a process according to the invention for the distillative workup of a methanol / water mixture.
  • a distillation column 1 is fed via a feed 3, a methanol / water mixture.
  • the distillation column 1 can be equipped with trays, unstructured packings, in particular random packings, or structured packings. If the distillation column contains 1 packs, then it is preferable to provide two packs, one pack above the inlet 3 and one pack below the inlet 3. Also, in each case more than one pack may be provided above the inlet 3 and below the inlet 3.
  • the feed 3 is preferably a side feed and is preferably arranged so that below the feed 3 1 to 50, in particular 2 to 10 theoretical plates and above 1 to 200, in particular 20 to 50 theoretical plates are.
  • the methanol / water mixture is separated into a substantially methanol-containing vapor stream and a substantially water-containing bottom stream.
  • the essentially methanol-containing vapor stream is removed via a vapor withdrawal 5 at the top of the column.
  • the vapor withdrawal 5 can be located at the top of the distillation column 1 as in the embodiment shown here, but it is also possible to carry out the vapor withdrawal 5, for example, as a side draw of the distillation column 1.
  • the execution of the vapor draw 5 as a side draw also allows the use of methanol, which has low-boiling shares, such as alkanes such as butanes.
  • the low-boiling fractions can be discharged at a low methanol loss at the top of the distillation column 1 in a vapor draw 5 designed as a side draw. However, it is preferred to position the vapor withdrawal 5 at the top of the distillation column 1. In order to discharge any liquid with the vapor from the distillation column 1, it is preferable to provide below the vapor withdrawal 5, a droplet separator, which is included as an additional installation in the distillation column 1. For example, an additional packing element or any commercially available droplet separator known to the person skilled in the art can be used as the droplet separator.
  • a bottom outlet 7 of the substantially water-containing bottom stream is removed.
  • a portion of the substantially water-containing bottom stream is withdrawn via an outlet 9 from the process.
  • Another part of the substantially water-containing bottom stream is at least partially vaporized in an evaporator 11 and fed to the distillation column 1 at the lower end via an inlet 13.
  • the ratio of the recirculated flow and the flow withdrawn via the outlet 9 can be adjusted via a valve 15.
  • the evaporator 11 is heated with the vapor stream removed via the vapor withdrawal 5 and essentially containing methanol.
  • the essentially methanol-containing vapor stream is compressed in a vapor compressor 17.
  • the pressure to which the substantially methanol-containing vapor stream in the vapor compressor 17 is compressed, is dependent on the temperature required for the evaporation of the substantially water-containing bottom stream 13.
  • the vapor compression can be done in one stage in a vapor compressor 17 or multi-stage by several successive vapor compressor. Also, a multi-stage compression is possible in an apparatus having a plurality of compressor stages. Due to the heat emission for evaporating the substantially water-containing bottom stream in the evaporator 11 at least a portion of the vapor stream is condensed.
  • the vapor stream is depressurized to the operating pressure of the distillation column 1 and recycled via an inlet 21 at the top of the distillation column 1 in this.
  • a portion of the essentially methanol-containing vapor stream is removed from the process via a methanol outlet 23.
  • the ratio of the vapor stream containing methanol fed back into the distillation column 1 and the vapor stream containing methanol substantially withdrawn from the process via the methanol outlet 23 is conveyed via a valve 25 set. The ratio of recirculated and withdrawn vapor stream is dependent on the desired purity of the methanol in the vapor stream.
  • FIG. 2 shows a process flow diagram for a process for the preparation of alkali methylate in a first embodiment.
  • a reaction column 31 is fed via an inlet 33 with aqueous alkali metal hydroxide, which is optionally mixed with methanol or a methanol / water mixture.
  • the alkali metal hydroxide solution can also be supplemented with methanol or a methanol / water mixture in a separate feed stream.
  • a heat exchanger 35 is received, through which the aqueous alkali metal hydroxide solution is passed before it flows into the reaction column 31.
  • the aqueous alkali solution is heated to the temperature of the feed point.
  • the aqueous alkali solution is partially evaporated in the heat exchanger 35.
  • the feed 33 for adding the aqueous alkali metal hydroxide, which is optionally admixed with methanol or a methanol / water mixture is positioned at the upper end of the reaction column 31.
  • vaporous methanol is introduced into the reaction column 31.
  • further vaporous methanol can be fed at the upper end of the reaction column via one or more further methanol feeds 39.
  • the further methanol feeds 39 are preferably 1 to 10 theoretical plates, in particular 1 to 3 theoretical plates below the feed 33 for the aqueous alkali.
  • the alkali methylate produced in the reaction column 31 is removed.
  • a portion of the Alkalimethylats is recycled via an evaporator 43 and a return 45 in the reaction column 31, so as to adjust the concentration of the bottoms outflow 41 withdrawn Alkalimethanolatives.
  • the methanol / water mixture removed at the top of the reaction column 31 is fed via the feed 3 to the distillation column 1.
  • About the bottom outlet 7 of the substantially water-containing bottom stream is removed from the distillation column 1.
  • a portion of the substantially water-containing bottom stream is at least partially evaporated in the evaporator 49 and returned to the distillation column 1 via the inlet 13.
  • the part of the substantially water-containing bottom stream which is not recycled to the distillation column 1 is withdrawn via the outlet 9.
  • the evaporator 49 in which the substantially water-containing bottom stream is at least partially evaporated, is a conventionally heated evaporator.
  • the heating of the evaporator 49 is preferably carried out with heating steam. But it is also any other, known in the art way conceivable to heat the evaporator 49.
  • the essentially methanol-containing vapor stream is taken off via the vapor withdrawal 5 at the top of the distillation column 1. From the vapor withdrawal 5 branches off a line 51, in which the vapor compressor 17 is positioned. In the vapor compressor 17, the substantially methanol-containing vapor stream is compressed to heat the evaporator 11.
  • the evaporator 11 is an intermediate evaporator, in which part of the methanol / water mixture to be separated in the distillation column 1 is evaporated. For this purpose, for example, a portion of the methanol / water mixture to be separated is removed via a side draw at the distillation column 1, passed through the evaporator and returned to the distillation column.
  • the outlet and the inlet, over which the methanol / water mixture to be evaporated is passed, can be at the level of the same theoretical separation stage or else at different positions on the distillation column 1. If inlet and outlet are at different positions, then it is preferred if the withdrawal, via which the evaporator 1 1 is supplied with the methanol / water mixture, is above the feed into the distillation column 1, through which the evaporated methanol / water mixture is returned to the distillation column 1 ,
  • the evaporator 1 which is used here as an intermediate evaporator, is preferably positioned so that below the evaporator 1 1 2 to 10 theoretical plates and above the evaporator 20 to 50 theoretical plates of the distillation column 1 are.
  • the substantially methanol-containing vapor stream is cooled by the heat transfer to the methanol / water mixture to be evaporated and optionally partially or even completely condensed.
  • the cooled, optionally at least partially condensed methanol stream is then passed over the Run 21 at least partially returned to the distillation column 1.
  • the uncondensed in the evaporator 1 1 part of the substantially methanol-containing vapor stream is returned via a steam line 53 behind the branch of the line 51 back into the vapor withdrawal 5.
  • the vapor vent 5 then opens into a condenser 55.
  • the vapor line 53 opens into the condenser 55 in addition to the vapor vent 5 and separated from it.
  • the condenser 55 a portion of the substantially methanol-containing vapor stream is condensed and fed back via the inlet 21 into the distillation column 1.
  • the part of the vapor stream containing essentially methanol condensed in the condenser 55 can first open into the inlet 21 coming from the evaporator 11 and all of the condensed methanol can be recycled together to the distillation column or the inlet 21 coming from the evaporator 11 Irrespective of the originating from the condenser 55 methanol flow into the distillation column 1.
  • the uncondensed in the condenser 55 portion of the substantially methanol-containing vapor stream is recycled via the methanol inlet 37 and optionally the at least one further methanol inlet 39 into the reaction column 31.
  • Methanol consumed in the reaction column 31 is added via a methanol inlet 57 at the top of the distillation column 1.
  • the purity of the vapor stream substantially withdrawn via the vapor withdrawal 5 and substantially containing methanol can be further increased. In this way, the proportion of water introduced into the reaction column 31 with the methanol is further reduced.
  • a part can be discharged.
  • inert substances that are introduced into the process can be discharged.
  • the inert substances enter the process in the form of gases dissolved in methanol and / or lye.
  • small amounts of sealing gas can enter the process via seals.
  • the cooling medium in the condenser 65 for example, water or brine is used. Preferred as a cooling medium is brine.
  • the portion not condensed in the condenser 65 which contains the gaseous inerts, is removed from the process and can be supplied, for example, to a torch or an exhaust gas scrubber for further treatment.
  • the condensed The resulting fraction is recycled via a reflux 67 in the distillation column.
  • the reflux 67 can, as shown here, open into the feed 21 or be formed as a separate feed into the distillation column 1.
  • the capacitor 55 can be dispensed with in one embodiment.
  • the return necessary to achieve the desired purity of the methanol is realized via the condenser 65.
  • the capacitor 65 may be either single-stage or multi-stage, preferably three-stage. In this case, it is cooled in one stage with air, in another stage with water and in the third stage with brine.
  • the vapor stream fed into the reaction column 31 via the methanol feed 37 and the further methanol feeds 39 and withdrawn via the vapor draw 5 from the distillation column 1 can be compressed in a vapor compressor 59.
  • FIG. 3 shows a process flow diagram for a process for the preparation of alkali methylate in a second embodiment.
  • the embodiment illustrated in FIG. 3 differs from the embodiment shown in FIG. 2 in that the vapor compressor 59, with which the fraction of the vaporous methanol withdrawn via the vapor withdrawal 5 from the top of the distillation column 1 and not condensed out in the condenser 55, is not compressed is included.
  • a further vapor compressor 61 is positioned in the vapor withdrawal 47 from the reaction column 31, which discharges into the distillation column 1 as feed 3.
  • the methanol / water mixture removed via the vapor withdrawal 47 from the reaction column 31 is additionally supplied with energy for the distillation.
  • the methanol / water mixture can be compressed to the pressure of the distillation column 1 when the distillation column 1 is operated at a higher pressure than the reaction column 31.
  • FIG. 4 shows a process flow diagram for a process for the preparation of alkali methylate in a third embodiment.
  • a separate reaction column 31 and a distillation column 1 are provided, but the columns are housed in a common column jacket in the form of a dividing wall column 71.
  • the lower region is separated by a dividing wall 73 into a first partial region 75 and a second partial region 77.
  • the first portion 75 serves as a reaction column and the second portion 77 as a stripping section of the distillation column.
  • aqueous alkali solution which is optionally mixed with methanol or a methanol / water mixture supplied.
  • methanol is fed in vapor form via the methanol inlet 37.
  • methanol can also be fed in vapor form via further methanol feeds 39.
  • the product, alkali metal methylate in methanol is withdrawn via the bottom outlet 41.
  • a portion of the stream removed via the bottom outlet 41 is returned to the first section 75 of the dividing wall column 71 via the evaporator 43 and the return line 45.
  • the reflux 45 preferably opens below the methanol inlet 37 into the first portion 75 of the dividing wall column 71.
  • the methanol / water mixture formed in the reaction flows in vapor form over the upper end of the dividing wall 73 into the upper part 79 of the dividing wall column, which serves as the reinforcing part of Distillation column 1 acts.
  • the second portion 77 of the dividing wall column 71 serves as a stripping section for the distillation of the methanol / water mixture.
  • a partial stream of the substantially methanol-containing vapor stream is fed via the line 51 to the vapor compressor 17, in which the vapor stream containing substantially methanol is compressed.
  • the compressed vapor stream then serves as heating steam in the evaporator 1 1.
  • the evaporator 1 1 is also arranged in the embodiment shown here as an intermediate evaporator in the stripping section of serving as a distillation column portion of the dividing wall column 71.
  • the condensed part is recycled via the inlet 21 in the upper part 79, preferably at the top of the dividing wall column 71. Also at the top of the dividing wall column opens the methanol feed 57, with the fresh methanol can be added to replace methanol consumed in the reaction to alkali metal.
  • the uncondensed in the evaporator 11 portion of the substantially methanol-containing vapor stream is fed via the vapor line 53 to the condenser 55.
  • the portion of the vapor stream essentially containing methanol and the fraction of the vapor stream essentially comprising methanol are not partially condensed via the vapor line 53 and the vapor fraction which is not passed via the vapor compressor 17.
  • the condensed fraction is also recycled via the top of the dividing wall column 71 into the dividing wall column 71.
  • the uncondensed part is recycled via the vapor compressor 59 and the methanol feeds 37 and 39 in the first portion 75, which serves as a reaction column, in the dividing wall 71 column.
  • the dividing wall column is preferably operated at a pressure in the range from 0.2 to 10 bar, in particular at a pressure in the range from 0.5 to 3 bar.
  • a substantially water-containing bottom stream is removed via the bottom outlet 7.
  • a portion of the substantially water-containing bottom stream is at least partially vaporized in the evaporator 49 and returned to the second portion 77, preferably at the bottom.
  • the second evaporator 49 is conventional, preferably heated with heating steam.
  • a vapor compressor in all embodiments, for example, a single or multi-stage turbocompressor or a screw compressor can be used.
  • the technical detail of the vapor compressor 17 is generally based on the manufacturer's instructions and is familiar to the expert. Thus, it is possible, for example, to connect the vapor compressor 17 with a mist eliminator.
  • the area of the evaporator 11 is preferably dimensioned so that the temperature difference is not more than 50 K, in particular not more than 30 K.
  • the compression of the substantially methanol-containing vapor stream in the vapor compressor 17 preferably takes place by a factor in the range of 1.5 to 19, in particular in the range of 2 to 4.
  • the exact value of Pressure increase in the vapor compressor 17 depends on the dimensioning of the heat transfer surface of the evaporator 11.
  • the dividing wall may either divide the column cross-section into two circular segments, but alternatively it is also possible to form the dividing wall coaxially, in which case it is preferable for the stripping section of the distillation to be of the internal region and the reaction in which the annular wall surrounding the partition is performed.
  • Inert outs can be carried out in the same way in the embodiments shown in FIGS. 3 and 4 as in the embodiment shown in FIG.
  • a condenser for discharging the inerts following the vapor compressor 11 in the conduit 53.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Abstract

L'invention concerne un procédé de traitement par distillation d'un mélange méthanol/eau, selon lequel un mélange méthanol/eau est acheminé dans une colonne de distillation (1), un flux de vapeur contenant essentiellement du méthanol est soutiré à la tête de la colonne de distillation (1) et un flux de bas de colonne contenant essentiellement de l'eau est soutiré au pied de la colonne de distillation (1), au moins une partie du flux de vapeur contenant essentiellement du méthanol est condensée et le flux de vapeur condensé est acheminé comme vapeur de chauffe dans un évaporateur (11) dans lequel au moins une partie du mélange méthanol/eau à séparer est évaporée. L'invention concerne en outre un procédé de préparation de méthylates alcalins dans une colonne de réaction (31), selon lequel du méthanol et une lessive alcaline sont acheminés dans la colonne de réaction (31), du méthylate alcalin dissous dans du méthanol est soutiré à l'extrémité inférieure de la colonne de réaction (31) et un mélange méthanol/eau est soutiré à l'extrémité supérieure de la colonne de réaction (31), puis le mélange méthanol/eau est traité par le procédé de traitement par distillation.
EP10703905A 2009-02-26 2010-02-17 Procédé de traitement par distillation d'un mélange méthanol/eau et procédé de préparation de méthylates alcalins Withdrawn EP2401045A1 (fr)

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EP10703905A EP2401045A1 (fr) 2009-02-26 2010-02-17 Procédé de traitement par distillation d'un mélange méthanol/eau et procédé de préparation de méthylates alcalins

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EP09153704 2009-02-26
PCT/EP2010/051981 WO2010097318A1 (fr) 2009-02-26 2010-02-17 Procédé de traitement par distillation d'un mélange méthanol/eau et procédé de préparation de méthylates alcalins
EP10703905A EP2401045A1 (fr) 2009-02-26 2010-02-17 Procédé de traitement par distillation d'un mélange méthanol/eau et procédé de préparation de méthylates alcalins

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EP2401045A1 true EP2401045A1 (fr) 2012-01-04

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US (1) US20110313207A1 (fr)
EP (1) EP2401045A1 (fr)
JP (1) JP2012518667A (fr)
CN (1) CN102333575A (fr)
AR (1) AR075612A1 (fr)
BR (1) BRPI1007998A2 (fr)
CA (1) CA2751983A1 (fr)
WO (1) WO2010097318A1 (fr)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITPI20100114A1 (it) * 2010-10-11 2012-04-12 Sime S R L Apparecchiatura e processo per separare 1,2,4 trimetilbenzene (pseudocumene) da una miscela contenente idrocarburi aromatici
WO2013042941A1 (fr) * 2011-09-19 2013-03-28 주식회사 엘지화학 Colonne à cloison de séparation bi-mode
AR093211A1 (es) * 2012-05-10 2015-05-27 Ypf Soc Anonima Metodo para preparar alcoxidos de metales alcalinos
CN103253819B (zh) * 2013-04-22 2014-02-12 潍坊沃尔特化学有限公司 一种处理三单体废水、提取硫酸钠的生产工艺
EP2801604B1 (fr) 2013-05-07 2017-04-12 Groupe Novasep Procédé chromatographique pour la production d'acides gras polyinsaturés hautement purifiés
CN103288593B (zh) * 2013-06-04 2015-06-03 江苏乐科热力科技有限公司 机械蒸气再压缩甲醇钠生产装置及方法
CN103387483B (zh) * 2013-08-14 2015-06-17 重庆紫光化工股份有限公司 甲醇碱金属盐的生产装置和工艺
CN105517682B (zh) * 2013-09-06 2017-10-13 株式会社大赛璐 利用再压缩蒸气的方法及成套设备
US10011502B2 (en) 2014-05-22 2018-07-03 Aquaback Technologies, Inc. Ammonia removal device
CN104147799A (zh) * 2014-08-27 2014-11-19 江苏凯茂石化科技有限公司 一种甲醇蒸发装置
CN104370275A (zh) * 2014-10-23 2015-02-25 杨传保 一种含水甲醇、乙醇与钠反应制氢气方法
DK3679999T3 (da) * 2019-01-09 2021-10-11 France Evaporation Fremgangsmåde og anlæg til behandling af en væske
CN109675334A (zh) * 2019-01-22 2019-04-26 天津乐科节能科技有限公司 叔丁醇钾直接接压缩自回热精馏系统及方法
EP4093725B1 (fr) * 2020-01-23 2024-01-31 Evonik Operations GmbH Procédé de fabrication à haut rendement énergétique d'alcools de sodium et de potassium
BR112022014470A2 (pt) 2020-01-23 2022-09-13 Evonik Functional Solutions Gmbh Processo para a produção simultânea de alcoolatos de sódio e potássio
TWI828051B (zh) 2021-02-05 2024-01-01 德商贏創運營有限公司 鹼金屬烷氧化物之高能效製備方法
EP4074684A1 (fr) * 2021-04-16 2022-10-19 Evonik Functional Solutions GmbH Procédé de production économique en énergie d'alcoolates alcalimétales
EP4074685A1 (fr) 2021-04-16 2022-10-19 Evonik Functional Solutions GmbH Procédé de production économique en énergie d'alcoolates alcalimétales
WO2022263032A1 (fr) * 2021-06-16 2022-12-22 Evonik Functional Solutions Gmbh Procédé de traitement d'un mélange méthanol/eau dans la production de méthoxydes de métaux alcalins dans une colonne de réaction
WO2024083336A1 (fr) 2022-10-20 2024-04-25 Evonik Operations Gmbh Procédé amélioré pour produire des méthoxydes de métaux alcalins
WO2024114899A1 (fr) 2022-11-30 2024-06-06 Evonik Operations Gmbh Procédé amelioré de production de méthoxydes de métaux alcalins

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB737453A (en) * 1950-06-28 1955-09-28 Montedison Spa Improvements in and relating to the rectification of liquid mixtures
FR70198E (fr) * 1956-04-05 1959-02-19 Procédé et appareil de distillation
US4566947A (en) * 1984-09-27 1986-01-28 Hidemasa Tsuruta Method of separating a mixed liquid into light and heavy fractions by distillation
DE19959153A1 (de) * 1999-12-08 2001-06-21 Basf Ag Verfahren zur Herstellung von Alkalimethylaten
DE102007025904A1 (de) 2007-06-01 2008-12-04 Evonik Degussa Gmbh Verfahren zur Herstellung von Alkalimetallalkoholaten

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2010097318A1 *

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JP2012518667A (ja) 2012-08-16
CA2751983A1 (fr) 2010-09-02
BRPI1007998A2 (pt) 2016-03-01
US20110313207A1 (en) 2011-12-22
CN102333575A (zh) 2012-01-25
AR075612A1 (es) 2011-04-20
WO2010097318A1 (fr) 2010-09-02

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