METHOD FOR THE ENERGY-EFFICIENT PRODUCTION OF ALKALIMETALLALCOHOLATES

Description

[0001] The present invention relates to a process for the production of alkali metal alkoxides in countercurrent by reactive rectification, wherein the alkali metal is selected from sodium and potassium. The process is carried out in at least one reaction column and at least one rectification column. The process according to the invention is characterized in that the heating steam used to operate the columns and thus to carry out the process is condensed, and the energy is utilized in the resulting condensate. 1. Background to the problem

[0002] The production of alkali metal alcoholates is an important industrial process.

[0003] Alkali metal alkoxides are used as strong bases in the synthesis of numerous chemicals, for example, in the production of pharmaceutical or agricultural active ingredients. Furthermore, alkali metal alkoxides are used as catalysts in transesterification and amidation reactions.

[0004] Alkali metal alcoholates (MOR) are produced by reactive distillation in a countercurrent distillation column from alkali metal hydroxides (MOH) and alcohols (ROH), whereby the product obtained according to the following reaction <1> The resulting reaction water is removed with the distillate.

[0005] Such a process principle is described, for example, in US Pat. No. 2,877,274 A, in which aqueous alkali metal hydroxide solution and gaseous methanol are run countercurrently in a rectification column. This process is described again in WO 01 / 42178 A1, in a fundamentally unchanged form.

[0006] Similar processes, which additionally use an entraining agent, such as benzene, are described in GB 377,631 A and US 1,910,331 A. The entraining agent serves to separate water from the water-soluble alcohol, and the condensate is subjected to phase separation to remove the water of reaction.

[0007] Accordingly, DE 96 89 03 C describes a process for the continuous production of alkali metal alcoholates in a reaction column, wherein the water-alcohol mixture withdrawn at the top is condensed and then subjected to phase separation. The aqueous phase is discarded, and the alcoholic phase is returned to the top of the column together with the fresh alcohol. EP 0 299 577 A2 describes a similar process, wherein the water is separated from the condensate using a membrane.

[0008] The most industrially important alkali metal alkoxides are those of sodium and potassium, particularly the methylates and ethylates. Their synthesis has been described extensively in the prior art, for example, in EP 1 997 794 A1.

[0009] In the prior art syntheses of alkali metal alcoholates by reactive rectification, vapors are typically obtained which comprise the alcohol used and water. For economic reasons, it is expedient to reuse the alcohol comprised in the vapors as a reactant in the reactive distillation. Therefore, the vapors are typically fed to a rectification column, and the alcohol contained therein is separated (described, for example, in GB 737 453 A and US 4,566,947 A). The alcohol thus recovered is then fed, for example, as a reactant to the reactive distillation. Alternatively or additionally, a portion of the alcohol vapor can be used to heat the rectification column (described in WO 2010 / 097318 A1). However, this requires compression of the vapor to achieve the temperature level required to heat the rectification column.

[0010] The energy required to operate the process is normally introduced into the process according to the invention via heating steam, for example, via heat exchangers (alternatively referred to as "heat exchangers") such as evaporators at the bottom of the column or for heating the alcohol or alkali metal hydroxide solution. During the energy transfer, the heating steam condenses, and the resulting liquid phase, the heating steam condensate, often still contains considerable amounts of residual heat. This results in the following disadvantages: On the one hand, it is energetically undesirable to allow this energy to dissipate unused. In addition, in industrial contexts (chemical parks and technology parks), condensates are usually collected in a condensate network. If this network is fed from different plants, the supplied condensates differ in temperature and pressure.In order to prevent pressure surges in the condensate network, each system connected to the network must actively cool the corresponding condensate, which in turn requires additional energy consumption.

[0011] The object of the present invention was therefore to provide a process for the production of alkali metal alkoxides that eliminates the aforementioned disadvantages and, in particular, allows for the efficient use of energy in the heating steam condensates. In addition to the advantageous energy savings, this should also allow for the easy, energy-efficient adjustment of the condensate to specific pressure and temperature values.

[0012] Surprisingly, a method has now been found that solves this problem. 2. Kurzzusammenfassung der Erfindung

[0013] The present invention therefore relates to a method according to claim 1. 3. Abbildungen

[0014] Image 1shows a process not according to the invention for the production of alkali metal alcoholates using various heat exchangers.

[0015] Such a plant comprises a reaction column RR A <1A>. At the top of the reaction column RR A <1A> an aqueous NaOH solution is used as reactant stream S AE2 <1A2> is added. Alternatively, a methanolic NaOH or KOH solution can be used as the reactant stream S AE2 <1A2> to produce the corresponding sodium or potassium methylate. The reactant stream S AE2 <1A2> can be heated via a heat exchanger WT <wa5>Energy is supplied, e.g. to preheat it. Above the bottom of the reaction column RR A <1A> Methanol is used as reactant stream S AE1 <1A1> is added in vapor form. The reactant stream S AE1 <1A1> can be heated via a heat exchanger WT <wa4>Energy is added, e.g. to preheat it. By converting the two reactant streams S AE1 <1A1> and S AE2 <1A2> is in the reaction column RR A <1A> a crude product mixture RP A <1A3> which comprises NaOCH 3 , water, CH 3 OH, NaOH, if S AE2 <1A2> NaOH. If S AE2 <1A2> KOH, a crude product mixture RP A <1A3> which comprises KOCH 3 , water, CH 3 OH and KOH.

[0016] At the bottom of the reaction column RR A <1A> the product flow S AS <1A4>, which comprises sodium methoxide or potassium methoxide dissolved in methanol. With the optional bottom evaporator VS RRA <wa1>at the bottom of the column RR A <1A> can be used to measure the concentration of sodium or potassium methylate solution S AS <1A4> can be set to the desired value. The optional sump evaporator VS RRA <wa2>may, if necessary, transfer energy to a part of S AS <1A4> which is transferred to the reaction column RR A <1A> is recycled. VS RRA <wa2>is used in particular to start the column RR A <1A>. The optional intermediate evaporator VZ RRA <wa3>opens up the possibility of applying energy to the raw product mixture RP A <1A3>. This will be assigned to the column RR A <1A> as current S RRAZ <1A7> taken, the current S RRAZ <1A7> in the intermediate evaporator VZ RRA <wa3>heated and then into the column RR A <1A>.

[0017] At the top of the reaction column RR A <1A> becomes a vapor stream S AB <1A5>. Part of the vapor stream S AB <1A5> can be added to the top of the reaction column RR A <1A> in a capacitor K RRA condensed and liquid as reflux to the top of the reaction column RR A <1A>. These are not in Image 1 shown embodiment, ie the adjustment of the reflux at the top of the reaction column RR A <1A>, but is optional.

[0018] The vapor stream S AB <1A5> is optionally connected to a heat exchanger WT <wa6>, via a compressor VD 31 <11> , a rectification column RD A <2> In the rectification column RD A <2> becomes a mixture GA <21> which comprises water and methanol, which is RD A <2> into a stream of vapor S DAB <24> comprising methanol and a bottom stream S DAS <22> water and raw material are separated. At the bottom of the column RD A <2> the swamp stream S DAS <22> at a collection point And AK <42> and can be partially recycled via the optional sump evaporator VS A <w7>or the sump evaporator VS A <w8>into the column RD A <2> be returned.

[0019] At the top of the rectification column RD A <2> becomes methanol vapor S DAB <24> at a collection point And AK <41> This can then optionally be discharged via the compressor <12> and to the reaction column RR A <1A> recycled, where it is used as reactant stream S AE1 <1A1> is used. The compressor <12> can also be used instead of the compressor VD 31 <11> be used.

[0020] The intermediate evaporator VZ A <w9>opens up a possibility to transfer energy to the mixture GA <21> This will be transferred to the column RD A <2> as electricity S AZ <23> taken, the current S AZ <23> in the intermediate evaporator VZ A <w9>heated and then into the column RD A <2> returned.

[0021] A stream of fresh methanol <25> can be added to the system via the rectification column RD A <2> This can be done via a heat exchanger WT <w10>Energy can be added. The fresh methanol can be fed to the rectification column RD A <2> be added directly.

[0022] Through the sump evaporator VS A <w8>energy is transferred to a part of S DAS <22> which is transferred to the rectification column RD A <1A> is recycled. The bottom evaporator VS A <w8>is used in particular to start the column RD A <2> . Image 1 shows the sump evaporator VS A <w8>heating with heating steam H 1 <84> based on the state of the art. Accordingly, the sump evaporator VS A <w8>Energy from heating steam H 1 <84> on recycled S DAS <22> and thus ultimately for the distillative separation of the mixture GA <21> made available.

[0023] The condensation temperature of the heating steam H 1 <84> must be adjusted according to the required heating power of the distillation. Since the temperature or pressure of the heating steam available in industrial plants H 3 <83> usually deviates from the values ​​desired in the specific case, H 3 <83> first to H 1 <84> be relaxed, which is controlled by a control valve <85> This occurs by dissipating parts of the heat in the heating steam H 3 <83> contained energy.

[0024] By transferring energy from H 1 <84> on S DAS <22> in the bottom evaporator VS A <w8>condensed H 1 <84> at least partially to the condensate K 1 <81> , which is stored in a condensate tank <86> where condensates may be <88> from other heat exchangers in the system Image 1 or even other plants (e.g. at integrated sites). The collected condensates must then be treated as a condensate stream <87> They can be disposed of or fed into the condensate network in chemical parks, for example. This not only wastes some of the energy contained in the condensate, but in many cases it is also necessary to adjust the condensate to a specific temperature, which requires additional energy, to avoid pressure surges in the condensate network.

[0025] This problem arises not only in the case where the heating steam H 1 <84> the sump evaporator VS A <w8>Heated systems. For systems that are Image 1 correspond, but in which instead of above or in addition to the sump evaporator VS A <w8>via one of the other heat exchangers energy from heating steam H 3 <83> The same problem arises if the entry is to be entered.

[0026] Image 2 shows an embodiment of the method according to the invention. The system corresponds to the one shown in Image 1 The characteristic feature of the process according to the invention is described using the bottom evaporator VS A <w8>The corresponding routing of the heating steam H 1 but is alternatively or additionally also connected to one of the other heat exchangers WT <wa1>until <wa6> , <w7> , <w9> , <w10>possible.

[0027] In accordance with the state-of-the-art procedure, the sump evaporator VS A <w8>Energy from heating steam H 1 <84> on S DAS <22> and thus ultimately for the distillative separation of the mixture GA <21> This creates a heating steam condensate K 1 <81> which is in the condensate tank <86> , if necessary with other condensates <88> , collected and expanded. The condensates <88> can result from heating via one of the other heat exchangers WT <wa1>until <wa6> , <w7> , <w9> , <w10>, if the plant has one, or, if the process according to the invention is carried out in the vicinity of another plant in which heating steam condensate is produced, from such a plant into the condensate tank <86> The key difference to the state-of-the-art processes is that at least part of the heating steam condensate K 1 <81> is relaxed, and thus a heating steam H 2 <82> , whose pressure p 2 lower than the pressure p 1 from H 1 <84> The resulting heating steam H 2 <82> is then filled with fresh heating steam H 3 <83> , whose pressure p 3 > p 2 and in the embodiment according to Image 2 also p 3 > p 1 This creates a heating steam / condensate / heating steam cycle H 1 <84> / K 1 <81> / H 2 <82> completed, and new heating steam is H 4 which is the same as the heating steam H 1 <84> with desired pressure (and thus desired temperature) and in the new round as heating steam H 1 <84> again to heat the sump evaporator VS A <w8>can be used.

[0028] In contrast to the state of the art methods, this results in the following advantages: A higher proportion of energy in the condensate K 1 is integrated into the process. By using the energy in the condensate K 1 used, the condensate K 1 less cooling before being fed into the condensate network to reduce the likelihood of water hammer in the condensate network. This also saves cooling energy.

[0029] Image 3 shows a further embodiment of the method according to the invention. This corresponds to the Image 2 described embodiment except that at the rectification column RD A <2> in the intermediate evaporator VZ A <w9>Energy from H 1 <84> on the mixture GA <21> In addition, the condensate tank <86> also with heating steam condensate <71> which is fed by condensation of heating steam <74> when operating the sump evaporator VS A <w8>is received.

[0030] Image 4 shows a further embodiment of the method according to the invention. This has the Image 3 described reaction column RR A <1A> and the rectification column RD A <2> In addition, the embodiment according to Image 4 the following features: In addition to the reaction column RR A <1A> the plant used in the process comprises a further reaction column RR B <1B>, in which the reactant stream S BE2 <1B2> an aqueous KOH solution is added. It can also be an aqueous or alcoholic solution of NaOH, advantageously S BE2 <1B2> is chosen so that the alkali metal encompassed by this current differs from that in S AE2 <1A2>. The reactant stream S BE2 <1B2> can be heated via a heat exchanger WT <wb5>Energy is supplied, e.g. to preheat it. If S BE2 <1B2> NaOH, S BE2 <1B2> in RR B <1B> with a possibly via the heat exchanger WT <wb4>preheated electricity S BE1 <1B1 > comprising CH 3 OH to a crude product mixture RP B <1B3> comprising NaOCH 3 , water, CH 3 OH, NaOH. If S BE2 <1B2> KOH, a crude product mixture RP B <1B3>, which comprises KOCH 3 , water, CH 3 OH, and KOH. In this embodiment, ROH is thus methanol.

[0031] At the bottom of the reaction column RR B <1B> the product stream S BS <1B4>, which comprises sodium methoxide or potassium methoxide dissolved in methanol. With the optional bottom evaporator VS RRB <wb1>at the bottom of the column RR B <1 B> can be used to measure the concentration of sodium or potassium methylate solution S BS <1A4> can be set to the desired value. The optional sump evaporator VS RRB <wb2>may, if necessary, transfer energy to a part of S BS <1B4> which is transferred into the reaction column RR B <1B> is recycled. VS RRB <wb2>is used in particular to start the column RR B <1B>. The optional intermediate evaporator VZ RRB <wb3>opens up the possibility of applying energy to the raw product mixture RP B <1B3>. This will be assigned to the column RR B <1B> as current S RRBZ <1B7>, the latter in the optional intermediate evaporator VZ RRB <wb3>heated and then into the column RR B <1B>.

[0032] At the top of the reaction column RR B <1B> becomes a vapor stream S BB <1B5>. Part of the vapor stream S AB <1B5> can be added to the top of the reaction column RR B <1 B> condensed in a condenser and returned in liquid form to the top of the reaction column RR B <1 B> These are not in Image 4 shown embodiment, ie the adjustment of the reflux at the top of the reaction column RR B <1B>, but is optional.

[0033] The vapor stream S BB <1B5> is optionally connected to a heat exchanger WT <wb6>led. S BB <1B5> is connected to the current S AB <1A5> and then, after the combined stream has been passed through a compressor VD 31 <11> was carried out, a rectification column RD A <2> The two currents S AB <1A5> and S BB <1B5> can also be fed separately into the rectification column RD A <2> are guided and only unite in this.

[0034] In the rectification column RD A <2> the distillative separation of the mixture takes place GA <21> into a stream of vapor S DAB <24> comprising ROH and a bottom stream S DAS <22> comprising water and raw materials. The swamp stream S DAS <22> is taken at a collection point And AK <42> at the bottom of the column RD A <2> and can be partially discharged via the optional sump evaporator VS A <w7>or the sump evaporator VS A <w8>at the bottom of the column RD A <2> back into the column RD A <2> The bottom evaporator VS A <w8>is used in particular to start the column RD A <2> .

[0035] At the top of the rectification column RD A <2> becomes methanol vapor S DAB <24> at a collection point And AK <41> This can then optionally be discharged via the compressor <12> and to the reaction column RR A <1A> recycled, where it is used as reactant stream S AE1 <1A1> or S BE1 <1B1> is used. The compressor <12> can also be used instead of the compressor VD 31 <11> be used.

[0036] The intermediate evaporator VZ A <w9>opens up a possibility to transfer energy to the mixture GA <21> This will be transferred to the column RD A <2> as electricity S AZ <23> taken, the current S AZ <23> in the intermediate evaporator VZ A <w9>heated and then into the column RD A <2> returned.

[0037] A stream of fresh methanol <25> can be added to the system via the rectification column RD A <2> This can be done via a heat exchanger WT <w10>Energy is supplied. The fresh methanol <25> can be used in the rectification column RD A <2> be added directly.

[0038] S DAS <22> is optionally supplied via a heat exchanger WT <w15>a rectification column RD x <3> forwarded. In RD x <3> This results in a mixture G x <31> comprising water and methanol.

[0039] In the rectification column RD x <3> the distillative separation of the mixture takes place G x <31> into a stream of vapor S XB <34> comprising ROH and a bottom stream S XS <32> comprising water and raw materials. The swamp stream S XS <32> is at the collection point The XS <52> removed and discharged. At the bottom of the column RD X <3> the swamp stream can S XS <32> partly again via the optional sump evaporator VS X <w11>or the optional sump evaporator VS X <w12>into the column RD X <3> The optional sump evaporator VS X <wa2>may, if necessary, transfer energy to a part of S XS <32> transferred to RD X <3> is recycled. VZ X <w12>is used in particular to start the column RD X <3> .

[0040] At the top of the rectification column RD X <3> becomes methanol vapor With XB <34> at a collection point The XK <51> This can then optionally be removed via the compressor <13> conducted and mixed with With DAB <24> to the reaction columns RR A <1A> and RR B <1B> recycled and used as reactant stream With AE1 <1A1> or S BE1 <1B1> is used.

[0041] The intermediate evaporator VZ X <w13>opens up a possibility to transfer energy to the mixture GX <31> This will be transferred to the column RD X <3> as electricity S XZ <33> taken, the latter in VZ X <w13>heated and then into the column RD X <3> returned.

[0042] A stream of fresh methanol <35> can be added to the system via the rectification column RD x <3> This can be done via a heat exchanger WT <w14>Energy is supplied. The fresh methanol <35> can be used in the rectification column RD x <3> be added directly.

[0043] About the intermediate evaporator VZ X <w13>Energy is extracted from heating steam H 1 <84> on S XS <32> and thus ultimately for the distillative separation of the mixture GX <31> This creates a heating steam condensate K 1 <81> which is stored in a condensate tank <86> , if necessary with other condensates <88> , can be collected. The condensates <88> can result from heating via one of the other heat exchangers <wa1>until <wa6> , <w7> , <w9> , <w10>, if the plant has one, or, if the process according to the invention is carried out in the vicinity of a corresponding plant in which heating steam condensate is produced, from such a plant into the condensate tank <86> be conducted (current <88> ) In Abbildung 4 a condensate <71> , which results from the heating of the sump evaporator VS X <w12>with heating steam <74> also in the condensate tank <86> collected.

[0044] At least part of the condensate in the collection tank <86> becomes further heating steam H 2 <82> , whose pressure p 2 lower than the pressure p 1 from H 1 <84> is expanded and evaporated. The resulting heating steam H 2 <82> is then filled with fresh heating steam H 3 <83> , whose pressure p 3 > p 1 and thus also p 3 > p 2 This creates a heating steam / condensate / heating steam cycle H 1 <84> / K 1 <81> / H 2 <82> completed, and new heating steam is H 4 which is the same as the heating steam H 1 <84> with desired pressure (and thus desired temperature) and in the new round as heating steam H 1 <84> again to heat the intermediate evaporator VZ X <w13>can be used.

[0045] Abbildung 5 shows the schematic structure of a steam jet DS <89> . The motive steam H 2 <83> Here, the heating steam, especially the medium-pressure steam from the steam network, is used. The suction steam H 2 <82> in particular the low-pressure steam from the condensate tank <86> Both are controlled via the control unit <90> mixed and via the outlet as mixed steam H 4 <84> to the corresponding heat exchanger WT, e.g. <w8> , <w9> , <w13>Via the control unit <90> The quantities of motive steam and suction steam can be adjusted, which increases the pressure and thus the condensation temperature of the mixed steam H 4 <84> can be set. 4. Detailed Description of Invention 4.1 Step (a1) of the invention measured traffic

[0046] In step (a1) of the process according to the invention, a reactant stream With AE1 comprising ROH with a reactant stream With AE2 comprising MA OH in countercurrent in a reactive rectification column RR A to a raw product mixture RP A comprehensively MA OR, water, ROH, MA OH.

[0047] According to the invention, a "reactive rectification column" is defined as a rectification column in which at least some of the reaction takes place according to step (a1) or step (a2) of the process according to the invention. It can also be abbreviated to "reaction column."

[0048] In step (a1) of the process according to the invention, at the lower end of RR A a bottom product stream S AS comprehensively ROH and MA OR. At the upper end of RR A becomes a vapor stream S AB comprehensively water and raw material.

[0049] "Vapor stream" means that the stream in question is a gaseous stream.

[0050] In the process according to the invention, R is a C 1 to C 6 hydrocarbon radical, preferably selected from the group consisting of methyl, ethyl, n -propyl, isopropyl, n -Butyl, dry -Butyl, iso -Butyl, cake -Butyl, isomers of pentyl, such as n -Pentyl, more preferably selected from the group consisting of methyl, ethyl, n -propyl, iso -Propyl, more preferably selected from the group consisting of methyl and ethyl. Particularly preferably, R is methyl and ROH is methanol.

[0051] MA is selected from sodium, potassium, and preferably sodium.

[0052] The reactant stream With AE1 comprises ROH. In a preferred embodiment, the mass fraction of ROH is S AE1 , based on the total mass of the reactant stream S AE1 , at ≥ 95 wt.%, more preferably at ≥ 99 wt.%, where With AE1 otherwise contains especially water.

[0053] The reactant stream used in step (a1) of the process according to the invention With AE1 The alcohol used (ROH) can also be commercially available alcohol with an alcohol mass fraction, based on the total mass of the reactant stream S AE1 , of more than 99.8 wt.% and a mass fraction of water, based on the total mass of the reactant stream S AE1 , of up to 0.2 wt.%.

[0054] The reactant stream With AE1 is preferably added in vapor form.

[0055] The reactant stream With AE2 comprises MA OH, preferably in a mass fraction of 10 to 75 wt.%, more preferably 20 to 55 wt.%, more preferably 48.5 wt.%, in each case based on the total mass of the stream With AE2 . In a preferred embodiment, With AE2 in addition to MA OH at least one further compound selected from water, ROH. More preferably With AE2 besides MA OH also water, then it is With AE2 an aqueous solution of MA OH.

[0056] Step (a1) of the process according to the invention is carried out in a reactive rectification column RR A Step (a2) of the process according to the invention is carried out in a reactive rectification column RR B carried out.

[0057] Preferably, the reaction column contains RR A or RR B Internals. Suitable internals include trays, structured packings or unstructured packings (packing elements). If the reaction column RR A or RR B If the reaction column contains trays, bubble trays, valve trays, tunnel trays, Thormann trays, cross-slotted bubble trays or sieve trays are suitable. RR A or RR B If the reactor contains multiple trays, trays are preferably selected in which a maximum of 5% by weight, preferably less than 1% by weight, of the liquid permeates through the respective trays. The design measures required to minimize permeation of the liquid are familiar to those skilled in the art. For valve trays, for example, particularly tightly closing valve designs are selected. By reducing the number of valves, the vapor velocity in the tray openings can also be increased to twice the value that is usually set. When using sieve trays, it is particularly advantageous to reduce the diameter of the tray openings while maintaining the number of openings.

[0058] When using structured or unstructured packings, structured packings are preferred with regard to the even distribution of the liquid.

[0059] For columns with unstructured packings, particularly with random packings, and for columns with structured packings, the desired liquid distribution characteristics can be achieved by reducing the liquid sprinkling density in the edge region of the column cross-section adjacent to the column shell, which corresponds to approximately 2 to 5% of the total column cross-section, by up to 100%, preferably by 5 to 15%, compared to the remaining cross-sectional areas. This can be achieved, for example, by the targeted distribution of the drip points of the liquid distributors or their bores using simple means.

[0060] To prevent droplet entrainment, the columns can also include appropriate internals known to those skilled in the art, such as wire mesh mist eliminators. Examples of such mist eliminators, such as those marketed by Sulzer under the name "KnitMesh V-MISTER™ Technology," are described in the brochure "Gas / Liquid Separation Technology" E10508 en 4.2018, Copyright © Sulzer Ltd 2018, available online at: https: / / www.sulzer.com / - / media / files / products / separation-technology / feed-inletdevices / gas_liquid separation technology.ashx?la=en.

[0061] The process according to the invention can be carried out either continuously or batchwise. It is preferably carried out continuously.

[0062] "Conversion of a reactant stream With AE1 comprising ROH with a reactant stream With AE2 comprising MA OH in countercurrent" is ensured according to the invention in particular by the fact that the addition point of at least part of the reactant stream With AE1 comprising ROH in step (a1) at the reaction column RR A below the feed point of the reactant stream With AE2 encompassing MA OH.

[0063] The reaction column RR A preferably comprises at least 2, in particular 15 to 40 theoretical plates between the point of addition of the reactant stream With AE1 and the addition point of the reactant stream With AE2 .

[0064] In particular, in the lower part of the reaction column RR A vaporous reactant stream With AE1 comprising ROH. Step (a1) of the process according to the invention also includes the case where part of the reactant stream With AE1 comprising ROH although below the feed point of the reactant stream With AE2 comprising alkali metal hydroxide MA OH, but still at the top or in the region of the top of the reaction column RR A This allows the dimensions in the lower part of the reaction column to be RR A If part of the reactant stream With AE1 comprising ROH, in particular methanol, at the upper end or in the region of the upper end of the reaction column RR A in particular in vaporous form, only a partial amount of 10 to 70 wt.%, preferably 30 to 50 wt.% [in each case based on the total amount of the alcohol ROH used in step (a1)] is added at the lower end of the reaction column RR A and the remaining portion is distributed in a single stream or over several substreams, preferably 1 to 10 theoretical plates, particularly preferably 1 to 3 theoretical plates below the feed point of the reactant stream With AE2 comprising MA OH added in vapor form.

[0065] In the reaction column RR A The reactant stream then continues With AE1 comprising ROH with the reactant stream With AE2 comprising MA OH according to the reaction described above <1> to MA OR and H 2 O, whereby, since this is an equilibrium reaction, these products are present in a mixture with the reactants ROH and MA OH. Accordingly, in step (a1) of the process according to the invention, in the reaction column RR A a raw product mixture RP A which, in addition to the products MA OR and water, also includes ROH and MA OH.

[0066] At the lower end of RR A the bottom product stream is then S AS (" S AS " can also be used as " S AP ") comprising ROH and MA OR.

[0067] At the upper end of RR A The alcohol stream still containing water, referred to above as "vapor stream S AB comprising water and raw material".

[0068] The amount of reactant stream With AE1 The alcohol ROH included is preferably selected so that it simultaneously serves as a solvent for the S AS obtained alkali alkoxide MA OR is used.

[0069] In a preferred embodiment of the method according to the invention, and in particular in cases where With AE2 in addition to MA OH also includes water, the ratio of the total weight (mass; unit: kg) of in step (a1) as reactant stream With AE1 used alcohol ROH to the total weight (mass; unit: kg) in step (a1) as reactant stream With AE2 used MA OH 2 : 1 to 50 : 1, more preferably 5 : 1 to 48 : 1, even more preferably 10 : 1 to 35 : 1, even more preferably 13 : 1 to 30 : 1.

[0070] The reaction column RR A is operated with or without, preferably without, return.

[0071] "No return" means that the upper end of RR A extracted vapor stream S AB comprising water and ROH or the one in optional step (a2) at the upper end of RR B extracted vapor stream S BB comprising water and raw material from the rectification column RD A according to step (b). The vapor stream S AB or the vapor stream removed in the optional step (a2) S AB is the first rectification column RD A preferably supplied in vapor form.

[0072] "With reflux" means that the reflux at the top of the respective column, in step (a1) of the reaction column RR A , extracted vapor stream S AB comprising water and ROH and in the optional step (a2) of the reaction column RR B , extracted vapor stream S BB including water and RAW not completely from RR A or RR B is discharged, i.e. not completely into the rectification column RD A but partly as return of the respective column, in step (a1) S AB i.e. the reaction column RR A , in the optional step (a2) S BB i.e. the reaction column RR B , In cases where such a reflux is established, the reflux ratio is preferably 0.005 to 0.99, more preferably 0.01 to 0.9, even more preferably 0.02 to 0.34, particularly preferably 0.025 to 0.27 and very particularly preferably 0.03 to 0.24. A reflux can be established by adding at the top of the respective column, in step (a1) of the reaction column RR A a capacitor b and in the optional step (a2) of the reaction column RR B a capacitor K RRB , in which the vapor flow S AB or S BB is at least partially condensed and the respective column RR A or RR B is fed back in. A reflux ratio is generally understood, and within the meaning of this invention, to be the ratio of the mass flow (kg / h) that is returned to the respective column in liquid form (reflux) to the mass flow (kg / h) that is discharged from the respective column in liquid form (distillate) or gaseous form (vapor).

[0073] In the embodiment in which the reaction column RR A a reflux is set, the reactant stream in step (a1) can With AE2 used alkali hydroxide MA OH is also at least partially mixed with the return stream and the resulting mixture is thus fed to step (a1).

[0074] Step (a1) of the process according to the invention is carried out in particular at a temperature T RRA in the range of 45 °C to 190 °C, preferably 47 °C to 170 °C, more preferably 60 °C to 150 °C and in particular at a pressure p RRA from 0.5 bar to 40 bar, preferably in the range from 0.75 bar to 20 bar, more preferably in the range from 0.9 bar to 10 bar, more preferably in the range from 1 bar to 7 bar, even more preferably at 1 bar to 5 bar.

[0075] The reaction column RR A In a preferred embodiment, it comprises at least one evaporator, which in particular consists of intermediate evaporators VZ RRA and sump evaporators VS RRA is selected, more preferably at least one bottom evaporator VS RRA .

[0076] As an "intermediate evaporator" VZ RRA or VZ RRB According to the invention, evaporators are referred to which are located above the bottom of the respective column, in particular above the bottom of the reaction column RR A or RR B , In particular, they contain raw product mixtures RP A or RP B evaporated.

[0077] As a "swamp evaporator" VS RRA and VS RRB According to the invention, evaporators are referred to which evaporate the bottom of the respective column, in particular the bottom of the reaction column RR A or RR B , In them, the bottom product stream S AS or S BS (" S BS " can also be used as " S BP ") at least partially evaporated.

[0078] An evaporator is usually located outside the respective reaction column or rectification column. The mixture to be evaporated in the evaporator is withdrawn from the column via a takeoff or "take-off point" and fed to at least one evaporator.

[0079] In the case of the reaction column RR A or RR B is used during the intermediate evaporation of the crude product mixture RP A or RP B , this as electricity Thanks or S RRBZ withdrawn and at least one intermediate evaporator VZ RRA or VZ RRB The evaporated mixture, possibly with a residual liquid, is fed back into the respective column via an inlet or "feed point". RR A or RR B If the evaporator is an intermediate evaporator, in particular an intermediate evaporator VZ RRA or VZ RRB The outlet through which the respective mixture is drawn off and fed to the evaporator is a side outlet, and the inlet through which the evaporated mixture is fed back to the column is a side inlet. If the evaporator is a bottom evaporator, i.e. it heats the column bottom, in particular a bottom evaporator VS RRA or VS RRB at least part of the bottoms effluent stream, in particular S AS or S BS , fed to the corresponding bottom evaporator, evaporated and returned to the respective column in the bottom area.

[0080] Alternatively, it is also possible, for example, to form tubes on a suitable tray when using an intermediate evaporator or in the bottom of the respective column, which are heated by the corresponding heat medium, such as H 1 or H 4 , flow through. In this case, evaporation takes place at the bottom or bottom of the column. However, it is preferable to locate the evaporator outside the respective column.

[0081] Suitable evaporators VD, which can be used as intermediate evaporators VZ and bottom evaporators VS, include natural circulation evaporators, forced circulation evaporators, forced circulation evaporators with expansion, boiler evaporators, falling film evaporators, or thin-film evaporators. A tube bundle or plate apparatus is typically used as the heat transfer component for the evaporator in natural circulation evaporators and forced circulation evaporators. When using a tube bundle exchanger, the heat medium, such as H 1 or H 4 , either flow through the tubes and the mixture to be evaporated flows around the tubes, or the heat medium flows around the tubes and the mixture to be evaporated flows through the tubes. In a falling-film evaporator, the mixture to be evaporated is usually added as a thin film on the inside of a tube, and the tube is heated from the outside. In contrast to a falling-film evaporator, a thin-film evaporator also features a rotor with wipers, which distributes the liquid to be evaporated into a thin film on the inside wall of the tube.

[0082] In addition to those mentioned, any other type of evaporator known to the person skilled in the art that is suitable for use in a rectification column or reaction column can also be used.

[0083] If the reaction column RR A or reaction column RR B an intermediate evaporator VZ RRA or VZ RRB it is preferred if the respective intermediate evaporator in the case of the reaction column RR A in the area of ​​the feed point of the reactant stream With AE1 or in the case of the reaction column RR B in the area of ​​the feed point of the reactant stream S BE1 This allows a major part of the heating energy to be transferred through the intermediate evaporator VZ RRA or VZ RRB For example, it is possible to introduce more than 80% of the energy via the intermediate evaporator. According to the invention, the intermediate evaporator VZ RRA or VZ RRB preferably arranged and / or designed so that more than 50%, in particular more than 75%, of the total energy required for the reactive rectification is introduced.

[0084] If the reaction column RR A or reaction column RR B an intermediate evaporator VZ RRA or VZ RRB it is also advantageous if the intermediate evaporator is arranged so that the reaction column RR A or RR B below the intermediate evaporator has 1 to 50, preferably 1 to 40, theoretical plates and above the intermediate evaporator has 1 to 200, preferably 1 to 40, theoretical plates. In particular, it is preferred if the reaction column RR A or RR B then has 2 to 10 theoretical plates below the intermediate evaporator and 20 to 50 theoretical plates above the intermediate evaporator.

[0085] If the reaction column RR A or reaction column RR B an intermediate evaporator VZ RRA or VZ RRB It is also advantageous if the side outlet (i.e. the "taking point The RRA " on the reaction column RR A or the "collection point The RRB " on the reaction column RR B ), through which the raw product mixture RP A or RP B the intermediate evaporator VZ RRA or VZ RRB and the side inlet (i.e. the "feed point Z RRA on the reaction column RR A or the "addition point Z RRB on the reaction column RR B ), through which the evaporated crude product mixture RP A or RP B from the intermediate evaporator VZ RRA or VZ RRB again the respective reaction column RR A or RR B fed, are at most 2 trays apart, preferably between the same trays of the reaction column RR A or reaction column RR B is positioned. However, it is also possible that the side outlet and side inlet are at different heights.

[0086] It is further advantageous that when the reaction column RR A or the reaction column RR B an intermediate evaporator VZ RRA or VZ RRB shows that the "collection point AND FATHER on the reaction column RR A or the "collection point AND RRB " on the reaction column RR B , and the "addition point Z RRA " on the reaction column RR A or the "addition point Z RRB " on the reaction column RR B , below the addition points of S AE2 or S BE2 lay.

[0087] In a preferred embodiment, when using an intermediate evaporator VZ RRA or VZ RRB in RR A or RR B the diameter of the reaction column RR A or RR B above the intermediate evaporator RR A or RR B larger than the diameter of the reaction column RR A or RR B below the intermediate evaporator VZ RRA or VZ RRB This has the advantage of saving investment costs.

[0088] In such an intermediate evaporator VZ RRA or VZ RRB can be used in the reaction column RR A liquid raw product mixture RP A comprising MA OR, water, ROH, MA OH or in the reaction column RR B liquid raw product mixture RP B comprising MB OR, water, ROH, MB OH are converted into the gaseous state.

[0089] By arranging one or more intermediate evaporators VZ RRA in the upper part of the reaction column RR A or from one or more intermediate evaporators VZ RRB in the upper part of the reaction column RR B the dimensions in the lower part of the reaction column RR A or RR B In the embodiment with at least one, preferably several intermediate evaporators VZ RRA or VZ RRB It is also possible to use partial streams of the ROH in liquid form in the upper part of the reaction column RR A or RR B to supply.

[0090] In step (a1) of the process according to the invention, at the lower end of the reaction column RR A a bottom product stream S AS comprehensively ROH and MA OR taken.

[0091] It is preferred that the reaction column RR A at least one sump evaporator VS RRA via the bottom product stream S AS then at least partially directed

[0092] According to the invention, bottom evaporators are located at the bottom of the reaction column RR A or RR B arranged and are then called " VS RRA " or " VS RRB" In such a bottom evaporator, the reaction column RR A or RR B bottom product stream S AS or S BS and ROH is at least partially removed therefrom, whereby the mass fraction of MA OR or MB OR in the respective bottom stream can be specifically adjusted.

[0093] Preferably, the bottom product stream withdrawn in step (a1) comprises S AS a mass fraction of MA OR in ROH in the range 1 to 50 wt.%, preferably 5 to 32 wt.%, more preferably 10 to 32 wt.%, even more preferably 15 to 32 wt.%, in each case based on the total mass of S AS .

[0094] The mass fraction of residual water in S AS is preferably < 1 wt.%, preferably < 0.5 wt.%, more preferably < 0.2 wt.%, based on the total mass of S AS .

[0095] The mass fraction of reactant MA OH in S AS is preferably < 1 wt.%, preferably < 0.5 wt.%, more preferably < 0.2 wt.%, based on the total mass of S AS . 4.2 Chart (a2) of the business collection (optional)

[0096] Step (a2) is optionally carried out according to the invention. In the optional step (a2), which takes place simultaneously with and spatially separated from step (a1) of the process according to the invention, a reactant stream S BE1 comprising ROH with a reactant stream S BE2 comprising MB OH in countercurrent in a reactive rectification column RR B to a raw product mixture RP B comprising MB OR, water, ROH, MB OH.

[0097] In the optional step (a2) of the process according to the invention, at the lower end of RR B a bottom product stream S BS comprehensively ROH and MB OR. At the upper end of RR B becomes a vapor stream S BB comprehensively water and raw material.

[0098] MB is selected from sodium, potassium, and preferably potassium.

[0099] The reactant stream S BE1 comprises ROH. In a preferred embodiment, the mass fraction of ROH is S BE1 , based on the total mass of the reactant stream S BE1 , at ≥ 95 wt.%, more preferably at ≥ 99 wt.%, where S BE1 otherwise contains especially water.

[0100] The reactant stream used in optional step (a2) of the process according to the invention S BE1 The alcohol used (ROH) can also be commercially available alcohol with an alcohol mass fraction, based on the total mass of the reactant stream S BE1 , of more than 99.8 wt.% and a mass fraction of water, based on the total mass of the reactant stream S BE1 , of up to 0.2 wt.%.

[0101] The reactant stream S BE1 is preferably added in vapor form.

[0102] The reactant stream S BE2 comprises MB OH, preferably in a mass fraction of 10 to 75 wt.%, more preferably 20 to 55 wt.%, more preferably 48 to 52 wt.%, in each case based on the total mass of the stream S BE2 . In a preferred embodiment, S BE2 in addition to MB OH at least one further compound selected from water, ROH. More preferably, S BE2 besides MB OH water, then it is S BE2 an aqueous solution of MB OH.

[0103] Step (a2) of the process according to the invention is carried out in a reactive rectification column (or "reaction column") RR B Preferred embodiments of the reaction column RR B are described in section 4.1.

[0104] "Conversion of a reactant stream S BE1 comprising ROH with a reactant stream S BE2 comprising MB OH in countercurrent" is ensured according to the invention in particular by the fact that the addition point of at least part of the reactant stream S BE1 comprising ROH in optional step (a2) on the reaction column RR B below the feed point of the reactant stream S BE2 encompassing MB OH.

[0105] The reaction column RR B preferably comprises at least 2, in particular 15 to 40 theoretical plates between the point of addition of the reactant stream S BE1 and the addition point of the reactant stream S BE2 .

[0106] In particular, in the lower part of the reaction column RR B vaporous reactant stream S BE1 comprising ROH. The optional step (a2) of the process according to the invention also includes the case where part of the reactant stream S BE1 comprising ROH although below the feed point of the reactant stream S BE2 comprising alkali metal hydroxide solution MB OH, but still at the top or in the region of the top of the reaction column RR B This allows the dimensions in the lower part of the reaction column to be RR B If part of the reactant stream S BE1 comprising ROH, in particular methanol, at the upper end or in the region of the upper end of the reaction column RR B in particular in vaporous form, only a partial amount of 10 to 70 wt.%, preferably 30 to 50 wt.% [in each case based on the total amount of the alcohol ROH used in optional step (a2)] is added at the lower end of the reaction column RR B and the remaining portion is distributed in a single stream or over several substreams, preferably 1 to 10 theoretical plates, particularly preferably 1 to 3 theoretical plates below the feed point of the reactant stream S BE2 comprising MB OH was added in vapor form.

[0107] In the reaction column RR B The reactant stream then continues S BE1 comprising ROH with the reactant stream S BE2 comprising MB OH according to the reaction described above <1> to MB OR and H 2 O, whereby, since this is an equilibrium reaction, these products are present in a mixture with the reactants ROH and MB OH. Accordingly, in the optional step (a2) of the process according to the invention, in the reaction column RR B a raw product mixture RP B which, in addition to the products MB OR and water, also includes ROH and MB OH.

[0108] At the lower end of RR B The bottom product stream is then obtained and removed S BS (" S BS " can also be used as " S BP ") comprising ROH and MB OR.

[0109] At the upper end of RR B The alcohol stream still containing water, referred to above as "vapor stream S BB comprising water and raw material".

[0110] The amount of reactant stream S BE1 The alcohol ROH included is preferably selected so that it simultaneously serves as a solvent for the S BP obtained alkali alkoxide MB OR is used.

[0111] In a preferred embodiment of the optional step (a2) of the process according to the invention, and in particular in cases where S BE2 in addition to MB OH also includes water, the ratio of the total weight (mass; unit: kg) of in step (a2) as reactant stream S BE1 used alcohol ROH to the total weight (mass; unit: kg) in step (a2) as reactant stream S BE2 MB OH used 2 : 1 to 50 : 1, more preferably 5 : 1 to 48 : 1, even more preferably 10 : 1 to 35 : 1, even more preferably 13 : 1 to 30 : 1.

[0112] This vapor stream S BB comprising water and ROH is fed to step (b) of the process according to the invention. Before being fed to step (b) of the process according to the invention, it is mixed with S AB mixed or separated from S AB to step (b) of the process according to the invention. Preferably, vapor stream S BB with S AB mixed and then the resulting mixed vapor stream is fed to step (b) of the process according to the invention.

[0113] The reaction column RR B is operated with or without, preferably without return.

[0114] In the embodiment in which the reaction column RR B a reflux is set, the reactant stream in the optional step (a2) S BE2 The alkali hydroxide MB OH used can also be at least partially mixed with the return stream and the resulting mixture can thus be fed to the optional step (a2).

[0115] The optional step (a2) of the process according to the invention is carried out in particular at a temperature T RRB in the range of 45 °C to 190 °C, preferably 47 °C to 170 °C, more preferably 60 °C to 150 °C and in particular at a pressure p RRB from 0.5 bar to 40 bar, preferably in the range from 0.75 bar to 20 bar, more preferably in the range from 0.9 bar to 10 bar, more preferably in the range from 1 bar to 7 bar, even more preferably at 1 bar to 5 bar.

[0116] The reaction column RR B In a preferred embodiment, it comprises at least one evaporator, which in particular consists of intermediate evaporators VZ RRB and sump evaporators VS RRB is selected. The reaction column RR B particularly preferably comprises at least one bottom evaporator VS RRB .

[0117] In the optional step (a2) of the process according to the invention, at the lower end of the reaction column RR B a bottom product stream S BS comprehensively ROH and MB OR taken.

[0118] It is preferred that the reaction column RR B at least one sump evaporator VS RRB via the bottom product stream S BS then at least partially directed.

[0119] Preferably, the bottom product stream withdrawn in step (a2) comprises S BS a mass fraction of MB OR in ROH range 1 to 50 wt.%, preferably 5 to 32 wt.%, more preferably 10 to 32 wt.%, even more preferably 15 to 32 wt.%, in each case based on the total mass of S BS .

[0120] The mass fraction of residual water in S BS is preferably < 1 wt.%, preferably < 0.5 wt.%, more preferably < 0.2 wt.%, based on the total mass of S BS .

[0121] The mass fraction of reactant MB OH in S BS is preferably < 1 wt.%, preferably < 0.5 wt.%, more preferably < 0.2 wt.%, based on the total mass of S BS .

[0122] In a preferred embodiment of the present process, step (a2) is carried out.

[0123] This has the advantage that two different alkali metal alkoxides can be produced without causing cross-contamination of one alkali metal alkoxide with the other or suffering product losses when switching the reactant MA OH to MB OH.

[0124] The optional step (a2) of the process according to the invention is carried out simultaneously with and spatially separated from step (a1). The spatial separation is achieved by carrying out steps (a1) and (a2) in the two reaction columns. RR A and RR B guaranteed.

[0125] In an advantageous embodiment of the invention, the reaction columns RR A and RR B accommodated in a column shell, the column being at least partially divided by at least one dividing wall. Such a column having at least one dividing wall is referred to according to the invention as a "TRD." Such dividing wall columns are known to the person skilled in the art and are described, for example, in US 2,295,256, EP 0 122 367 A2, EP 0 126 288 A2, WO 2010 / 097318 A1 and by I. Dejanović, Lj. Matijašević, 2. Olujić, Chemical Engineering and Processing 2010, 49, 559-580. In the dividing-wall columns suitable for the process according to the invention, the dividing walls preferably extend all the way to the bottom and particularly preferably span at least a quarter, more preferably at least a third, even more preferably at least half, even more preferably at least two-thirds, and even more preferably at least three-quarters of the column lengthwise. They divide the column into at least two reaction spaces in which spatially separate reactions can take place. The reaction spaces created by the at least one dividing wall can be of the same or different sizes.

[0126] In this embodiment, the bottom product streams can be separated from the respective areas by the dividing wall S AS and S BS be removed separately and preferably via the bottom evaporator attached to each reaction chamber formed by the at least one reaction wall VS RRA or VS RRB by removing ROH from S AS or S BS a desired concentration of MA OR or MB OR can be set. 4.3 Schritt (b) of the Experimental Museum Consumer

[0127] In step (b) of the process according to the invention, the vapor stream S AB , and, if step (a2) is carried out, the vapor stream S BB , mixed with S AB or separated from S AB , into a rectification column RD A so that in the rectification column RD A a mixture GA comprising water and raw material.

[0128] In the optional embodiment of the process according to the invention, in which step (a2) is carried out, the vapor stream S BB preferably mixed with S AB and then the resulting mixed vapor into the rectification column RD A led.

[0129] The vapor stream S AB and, in cases where the optional step (a2) is carried out, the vapor stream S BB , can be compressed in one embodiment of the present invention before being fed into the rectification column RD A This can be done via a compressor VD 31 happen.

[0130] The skilled person may, in accordance with their specialist knowledge, provide one or more compressors between the columns. In particular, for gaseous streams connecting two or more columns, a compressor / compression step must always be provided if the pressure in the column into which a gaseous stream is fed is higher than the pressure in the column from which the stream in question exits.

[0131] It goes without saying that even in the embodiments in which the optional step (a2) is carried out, and S BB separated from S AB into the rectification column RD A is directed to S AB and S BB in the rectification column RD A so that in any case after carrying out step (b) a mixture GA comprising water and raw material in the rectification column R.D.A. is received.

[0132] As a rectification column R.D.A. In step (b) of the process according to the invention, rectification columns known to the person skilled in the art can be used. The rectification column preferably contains R.D.A. Internals. Suitable internals include trays, unstructured packings, or structured packings. Trays typically used are bubble-cap trays, sieve trays, valve trays, tunnel trays, or slotted trays. Unstructured packings are generally random packings. Raschig rings, Pall rings, Berl saddles, or Intalox ® saddles are typically used. Structured packings are marketed, for example, under the trade name Mellapack ® by Sulzer. In addition to the internals mentioned, other suitable internals are known to those skilled in the art and can also be used.

[0133] Preferred internals exhibit a low specific pressure drop per theoretical plate. Structured packings and random packings, for example, have a significantly lower pressure drop per theoretical plate than trays. This has the advantage that the pressure drop in the rectification column remains as low as possible, thus limiting the mechanical power of the compressor and the temperature of the alcohol / water mixture to be evaporated. EN remains low.

[0134] If in the rectification column R.D.A. Structured packings or unstructured packings are included, these can be divided or there can be a continuous packing. However, at least two packing sections are usually provided, one packing section above the inlet point of the vapor stream to be separated (this is S AB or, mixed or separately, S AB and S BB ) and a packing section below the inlet point of the vapor stream to be separated. If a packing is used, for example a random packing, the packings are usually supported on a suitable support system. An embodiment in which packings are arranged above the inlet and trays are arranged below the inlet in the rectification column is preferred. R.D.A. are attached.

[0135] The rectification column R.D.A. may also include internals to prevent droplet entrainment, as required for the reaction column RR A are described.

[0136] In an advantageous embodiment of the invention, the reaction column RR A according to step (a1), or reaction columns RR A and RR B in the preferred embodiment described above, in which step (a2) is carried out, and the rectification column R.D.A. according to step (b) to separate the mixture EN accommodated in a column shell, the column being at least partially divided by at least one dividing wall, or in the preferred embodiment described above in which step (a2) is carried out, by at least two dividing walls, the at least one dividing wall or the at least two dividing walls extending to the bottom of the column. As described under point 4.2, this is then again a dividing wall column.

[0137] In this case, in a part of the TRD the reaction to the crude product mixture RP A according to step (a1) or the crude product mixtures RP A and RP B according to steps (a1) and (a2), wherein the reactant stream S AE2 and if necessary the reactant stream S BE2 is added below, but approximately at the level of the upper end of the partition wall and the reactant flow S AE1 and if necessary the reactant stream S BE1 The alcohol / water mixture formed above the feed stream feed point is then distributed above the dividing wall over the entire column section, which serves as the rectification column's rectification section. R.D.A. The second lower part of the column, separated by the dividing wall, is the stripping section of the rectification column R.D.A. The energy required for distillation is then supplied via an evaporator at the lower end of the second part of the column separated by the dividing wall, whereby this evaporator can be heated conventionally or with heating steam, for example H 1 or H 4 If the evaporator is heated conventionally, an intermediate evaporator can be provided, which is heated with heating steam, for example H 1 or H 4 , can be heated.

[0138] At the end of step (b) of the process according to the invention, a mixture EN comprising water and raw material in the rectification column R.D.A. The composition of the mixture EN results in particular from the composition of the vapor stream S AB or, if step (a2) is carried out, in particular proportionally from the composition of the two vapor streams S AB and S BB . 4.4 Schritt (c) of the inventive Verfahrens

[0139] In step (c) of the process according to the invention, the mixture EN including water and raw materials in R.D.A. into a vapor stream containing ROH S DAB at the upper end of R.D.A. and a swamp stream S DAS comprising water and RAW at the lower end of R.D.A. separated.

[0140] The pressure p A in R.D.A. can be adjusted by a person skilled in the art according to their specialist knowledge. It is preferably in the range between 1 bar and 20 bar, preferably 1 bar and 15 bar, more preferably 1 to 10 bar.

[0141] The temperature TA in R.D.A. can be adjusted by a specialist according to their expertise. It is preferably in the range of 40 °C to 220 °C, preferably 60 °C to 190 °C.

[0142] The separation according to step (c) of the process according to the invention is a distillative separation of the alcohol-water mixture known to the person skilled in the art EN .

[0143] At the bottom (another word for "bottom" is "at the bottom") of the rectification column R.D.A. becomes a current S DAS containing alcohol.

[0144] At the head (another word for "head" is "at the top") of the rectification column R.D.A. In addition, the vapor flow S DAB comprehensively ROH. The preferred mass fraction of ROH in this vapor stream S DAB is ≥ 99 wt.%, preferably ≥ 99.6 wt.%, more preferably ≥ 99.9 wt.%, in each case based on the total mass of S DAB , the rest being mainly water.

[0145] The swamp stream S DAS is taken at a collection point It is at the lower end of R.D.A. out of R.D.A. and the vapor flow S DAB at a collection point E AK at the upper end of R.D.A. out of R.D.A. led.

[0146] "Collection point E AK at the upper end of R.D.A. " means in the context of the present invention that E AK is mounted on the column so that the vapor flow S DAB as top stream or as side draw above the internals in the rectification column R.D.A. is taken.

[0147] "Collection point It is at the lower end of R.D.A. " means in the context of the present invention that It is is attached to the column so that the bottom stream S DAS as bottom stream or as side draw below the internals in the rectification column R.D.A. is taken.

[0148] In an optional embodiment of the process according to the invention, at one rectification column R.D.A. at a collection point E A Z at least one other S DAS and S DAB different current S A Z comprising raw material and water from R.D.A. directed, energy is transferred to it, and in R.D.A. returned, whereby the position of the extraction point E A Z to R.D.A. between the two sampling points It is and E AK The current S A Z includes the mixture EN .

[0149] In this optional embodiment of step (c) of the process according to the invention, it is possible to add to the mixture EN In a preferred embodiment, this is done in such a way that the mixture EN as electricity S A Z extracted and via an intermediate evaporator VZ A in which energy is supplied by a heat medium, in particular by heating steam H 1 or H 4 or a different heat medium W 1 , on S A Z or EN This energy transfer can be advantageously carried out by mixing the mixture EN as electricity S A Z and W, or the mixture EN as electricity S A Z and the heating steam H 1 or H 4 via an intermediate evaporator VZ A be directed.

[0150] At least part of the alcohol obtained during distillation (ROH) in the vapor stream S DAB is preferred to the reaction column RR A at least as part of the reactant stream S AE1 and, in cases where step (a2) is carried out in the process according to the invention, alternatively or additionally the reaction column RR B at least as part of the reactant stream S BE1 supplied.

[0151] In step (c) the vapor obtained in step (a1) or steps (a1) and (a2) is separated by distillation S AB or S AB and S BB These essentially include the alcohol RAW and water. In particular, S AB or S AB and S BB a water-alcohol mixture in which the mass fraction of ROH is preferably in the range > 80 wt.%, more preferably > 85, even more preferably > 90 wt.% (based on the total mass of S AB or S AB and S BB ). This means that in particular EN an alcohol-water mixture in which the mass fraction of ROH is preferably in the range > 80 wt.%, more preferably > 95 wt.%, even more preferably > 90 wt.% (based on the total mass of EN ) lies.

[0152] The bottoms stream withdrawn in step (c) S DAS comprises ROH in a mass fraction of in particular 0.005 to 95 wt.%, based on the total mass of S DAS . Preference is given to 25 to 95 wt.% in the cases where step (d) is carried out, and 0.005 to 3 wt.% in the cases where step (d) is not carried out, in each case based on the total mass of S DAS . Preferably includes S DAS Besides the alcohol, RAW is essentially water.

[0153] In the process according to the invention, the alcohol ROH is consumed and, particularly in the case of continuous operation, it must therefore be replaced with fresh alcohol ROH.

[0154] Fresh alcohol ROH is in particular fed into at least one of the columns selected from reactive rectification column R.D.A. , reaction column RR A added and, if step (a2) is carried out, alternatively or additionally into the reaction column RR B added and, if step (d) is carried out, alternatively or additionally into the at least one reaction column RD X admitted.

[0155] The fresh alcohol ROH is supplied directly as a reactant stream S AE1 comprehensively ROH into the reaction column RR A or in the embodiments in which step (a2) is carried out, into the reaction columns RR A and RR B .

[0156] At least part of the sample taken at the sampling point E AK at the top of the rectification column R.D.A. extracted vapor stream S AB is preferred to the reaction column RR A at least as part of the reactant stream S AE1 and, in cases where step (a2) is carried out in the process according to the invention, alternatively or additionally the reaction column RR B at least as part of the reactant stream S BE1 supplied.

[0157] In a further preferred embodiment in which step (d) is carried out, the vapor stream S X B at least partly as reactant stream S AE1 in step (a1) and optionally as reactant stream S BE1 be used in step (a2).

[0158] In the particularly preferred embodiment in which step (d) is carried out, S DAB and S X B at least partly as reactant stream S AE1 in step (a1) and optionally as reactant stream S BE1 in step (a2). Then S DAB and S X B separately from the respective reactive rectification column RR A or RR B or first mixed together and then fed to the respective reactive rectification column RR A or RR B In this embodiment, preference is given to S DAB and S X B first mixed together and then fed to the respective reactive rectification column RR A or RR B supplied.

[0159] In this preferred embodiment, it is even more preferred if the fresh alcohol ROH is added to at least one of the rectification columns RD A , RD X , prefers both columns R.D.A. and RD X , is added.

[0160] When the fresh alcohol ROH of the rectification column R.D.A. or RD X is added, it is preferably added either in the rectification section of the respective rectification column or directly at the top of the respective rectification column. The optimal feed point depends on the water content of the fresh alcohol used and, on the other hand, on the desired residual water content in the vapor stream. R.D.A. or RD X The higher the water content in the alcohol used and the higher the purity requirement in the vapor stream S DAB or S X B is, the more favorable it is to feed a few theoretical plates below the top of the rectification column R.D.A. or RD X . Up to 20 theoretical plates below the top of the rectification column are preferred R.D.A. or RD X and in particular 1 to 5 theoretical plates.

[0161] When the fresh alcohol ROH of the rectification column R.D.A. or R.D.B. is added, it is added at temperatures up to the boiling point, preferably at room temperature. A gaseous addition of the fresh alcohol (ROH) is also possible. A separate inlet can be provided for the fresh alcohol. 4.5 Schritt (d) des invention Verfahrens (optional)

[0162] Step (d) of the process according to the invention is optionally carried out. In the optional step (d) of the process according to the invention, S DAS , in whole or in part, in at least one of R.D.A. various rectification column RD X into a stream of vapor S X B comprehensively RAW at the upper end of RD X and a swamp stream S XS comprising water and possibly raw material at the lower end of RD X separated.

[0163] As a result, when step (d) is carried out, a mixture GX comprising water and ROH in the at least one rectification column RD X before.

[0164] The swamp stream S XS is taken at a collection point E XS at the lower end of at least one rectification column RD X from this and the vapor flow S X B is taken at a collection point XK at the top of at least one rectification column RD X derived from this.

[0165] "Collection point XK at the top of at least one rectification column RD X " means in the context of the present invention that XK so at least one rectification column RD X It is appropriate that the vapor flow S X B at least one rectification column RD X as a top stream or as a side draw above the internals.

[0166] "Collection point E XS at the lower end of at least one rectification column RD X " means in the context of the present invention that E XS is attached to the column so that the bottom stream S XS at least one rectification column RD X as a bottom stream or as a side draw below the internals.

[0167] The pressure p X in RD X can be adjusted by a person skilled in the art according to their specialist knowledge. It is preferably in the range between 1 bar and 20 bar, preferably 1 bar and 15 bar, more preferably 1 bar to 10 bar.

[0168] The temperature TX in RD X can be adjusted by a specialist according to their expertise. It is preferably in the range of 40 °C to 220 °C, preferably 60 °C to 190 °C.

[0169] The feature " at least one of R.D.A. various rectification column RD X " means that the optional step (d) of the process according to the invention comprises the case where the separation of the vapor stream S DAS in only one rectification column RD X However, it also includes the case where the separation of the vapor stream S DAS in more than one rectification column RD X is carried out.

[0170] In the embodiment of the present invention in which more than one column RD X for the separation of S DAS is used, and thus more than one column RD X on the column R.D.A. follow, the first of these columns RD X , into which the swamp stream S DAS out of R.D.A. is referred to as "RD X1 ", and the column(s) following column RD X1, into which the bottoms stream from RD X , is routed as "RD x2 " etc.

[0171] Thus, each rectification column RD X , which in addition to the first rectification column " RD X1 " is used, generally referred to as " RD X(n+1) ", where n is an integer and the total number of the rectification column RD X1 number of rectification columns RD X At the same time, the column RD X(n+1) integer "n" to be assigned the number of columns RD X , which is located between the column in question RD X(n+1) and R.D.A. lies or lie.

[0172] Accordingly, with a total of two columns RD X n = 1, with three columns RD X n = 2 etc.

[0173] In the embodiments of the present invention in which more than one column RD X for the separation of S DAS is used, then results in the rectification column RD X , one vapor stream each S XB1 comprehensively RAW at the upper end of RD X , and a swamp stream S XS1 comprising water and possibly raw material at the lower end of RD X1 . In the rectification column RD x1 the mixture G X1 comprising water and raw materials.

[0174] In each additional rectification column RD X(n+1) This results in a vapor flow S XB(n+1) comprehensively RAW at the upper end of RD X(n+1) and a swamp stream S XS(n+1) comprising water and possibly raw material at the lower end of RD X(n+1) . In the rectification column RD X(n+1) the mixture G X(n+1) comprising water and raw material. "n" is an integer with the meaning described above.

[0175] In the embodiment of the present invention in which more than one column RD X for the separation of S DAS is used, this separation is then carried out in such a way that S DAS in RD X , into a stream of vapor S XB1 comprehensively RAW at the upper end of RD X , and a swamp stream S XS1 comprising water and possibly raw material at the lower end of RD X , is separated. In each RD X , following column RD X(n+1) then the swamp stream S XSn the previous column RD Xn into a stream of vapor S XB(n+1) comprehensively RAW at the upper end of RD X(n+1) and a swamp stream S XS(n+1) comprising water and possibly raw material at the lower end of RD X(n+1) separated.

[0176] In summary, this embodiment also S DAS into a stream of vapor S XB comprising RAW [which then consists of the individual vapor streams S XB1 and S XB(n+1) composed], and a swamp stream S XS comprising water and optionally RAW [which is then added to the sump stream S XS(n+1) the last column RD X(n+1) corresponds] separated.

[0177] The swamp stream S DAS In one embodiment of the present invention, the product can be pumped into the at least one rectification column RD X Similarly, with several rectification columns RD X One pump is used to reduce the sump flow S XSn a rectification column RD Xn into the rectification column RD X(n+1) to transport.

[0178] As a rectification column RD X Suitable rectification columns are known to the person skilled in the art. Preferred configurations such as internals etc. in RD X are those in section 4.3 for RD A described.

[0179] The separation according to step (d) of the process according to the invention is a distillative separation of the alcohol-water mixture known to the person skilled in the art G X , which is in at least one rectification column RD X results when the sump stream S DAS into which at least one rectification column RD X is initiated.

[0180] If only one rectification column RD X used, the in step (d) on the rectification column RD X withdrawn swamp stream S XS ROH in a mass fraction of in particular 0.0001 to 3 wt.%, preferably 0.005 to 1 wt.%, in each case based on the total mass of S XS1 Preferably includes S XS Besides the alcohol, RAW is essentially water.

[0181] If more than one rectification column RD X used, the swamp stream S XS(n+1) , which is located at the last rectification column RD X(n+1) was taken, ROH in a mass fraction of in particular 0.0001 to 3 wt.%, preferably 0.005 to 1 wt.%, in each case based on the total mass of S XS , preferably includes S XS Besides the alcohol, RAW is essentially water.

[0182] At the top (another word for "head" is "at the upper end") of at least one rectification column RD X In addition, the vapor flow S XB comprehensively ROH. The preferred mass fraction of ROH in this vapor stream S XB is ≥ 99 wt.%, preferably ≥ 99.6 wt.%, more preferably ≥ 99.9 wt.%, in each case based on the total mass of S XB , the rest being mainly water.

[0183] In an optional embodiment of the process according to the invention, at least one rectification column RD X at a collection point E XZ at least one other S XS and S XB different current S XZ comprising raw material and water from at least one rectification column RD X passed, energy is transferred to it and at least one rectification column is added to the same RD X returned, whereby the position of the extraction point E XZ at least one rectification column RD A between the two sampling points E XS and E XK The current S XZ includes the mixture G X .

[0184] In this optional embodiment of the optional step (d) of the process according to the invention, it is possible to add to the mixture G X In a preferred embodiment, this is done in such a way that the mixture G X as electricity S XZ via an intermediate evaporator VZ X in which energy is supplied by a heat medium, in particular by heating steam H 1 or H 4 or a different heat medium W 1 , on S XZ or G X This energy transfer can be advantageously carried out by mixing the mixture G X as electricity S XZ and W, or the mixture G X as electricity S XZ and the heating steam H 1 or H 4 via an intermediate evaporator VZ X be directed.

[0185] At least part of the sample taken at the sampling point E XK at the top of at least one rectification column RD X extracted vapor stream S XB is preferred to the reaction column RR A at least as part of the reactant stream S AE1 and, in cases where step (a2) is carried out in the process according to the invention, alternatively or additionally the reaction column RR B at least as part of the reactant stream S BE1 supplied.

[0186] If both S DAB as well as S XB at least as part of the reactant stream S AE1 and, in cases where step (a2) is carried out in the process according to the invention, alternatively or additionally the reaction column RR B at least as part of the reactant stream S BE1 these can be mixed beforehand and then used as a reactant stream S AE1 or S BE1 into the respective reaction column RR A or RR B or they are fed as separate streams into the respective reaction column RR A or RR B fed in. 4.6 Schritte (e) und (h) des erfindungsgemäßen Verfahrens

[0187] In step (e) energy, preferably heat, is extracted from a heating steam H 1 with pressure p 1 on at least one component Q, transferred, whereby the heating steam H 1 at least partially condensed and thus a condensate K 1 is received.

[0188] In step (h) energy is extracted from a heating steam H 4 with pressure p 4 on at least one component Q 2 which in particular the heating steam H 4 at least partially condensed and thus a condensate K 2 is received.

[0189] As heating steam H 1 or H 4 Any vapor stream can be used within the scope of the invention. For the purposes of the invention, it can comprise, for example, n-butane or water. It is preferably steam.

[0190] "Component Q 1 " and the "component Q 2 " are collective terms for the mixtures and raw products S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S XS .

[0191] Q 1 In other words, is from the group consisting of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB selected, and may, if step (a2) is carried out, alternatively or additionally be selected from the group consisting of S BE1 , S BE2 , RP B , S BS , S BB and may also, when step (d) is performed, alternatively or additionally be selected from the group consisting of G X , S XB , S XS be selected.

[0192] The same applies to Q 2 : Q 2 is from the group consisting of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB selected, and may, if step (a2) is carried out, alternatively or additionally be selected from the group consisting of S BE1 , S BE2 , RP B , S BS , S BB and may also, when step (d) is performed, alternatively or additionally be selected from the group consisting of G X , S XB , S XS be selected.

[0193] This means that in the embodiments of the process according to the invention in which step (a2) is carried out but step (d) is not carried out, the component Q 1 out of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB is selected, and in the embodiments of the process according to the invention in which step (d) is carried out but step (a2) is not carried out, the component Q 1 out of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , G X , S XB , S XS is selected, and in the embodiments of the process according to the invention in which both steps (a2) and (d) are carried out, the component Q 1 out of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S XS is selected.

[0194] This means that in the embodiments of the process according to the invention in which step (a2) is carried out but step (d) is not carried out, the component Q 2 out of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB is selected, and in the embodiments of the process according to the invention in which step (d) is carried out but step (a2) is not carried out, the component Q 2 out of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , G X , S XB , S XS is selected, and in the embodiments of the process according to the invention in which both steps (a2) and (d) are carried out, the component Q 2 out of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S XS is selected.

[0195] Q 1 and Q 2 are the same or different and are preferably the same.

[0196] If Q 1 and Q 2 are the same, this means according to the invention that the mixture or stream is selected from S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S XS , to which in step (e) energy from heating steam H 1 is transferred, is equal to the mixture or stream selected from S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S xs , to which in step (h) energy from heating steam H 4 is transferred.

[0197] If Q 1 and Q 2 are different, this means according to the invention that the mixture or stream is selected from S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S xs , to which in step (e) energy from heating steam H 1 is different from the mixture or stream selected from S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S xs , to which in step (h) energy from heating steam H 4 is transferred.

[0198] In the embodiments of the present invention in which more than one column RD X for the separation of S DAS is used, refers to " S XS " the group consisting of the swamp stream S xs , and the n swamp streams S XS(n+1) , where " S XS(n+1) " the respective bottom stream of the rectification column RD x(n+1) designated.

[0199] In the embodiments of the present invention in which more than one column RD X for the separation of S DAS is used, refers to " S XB " the group consisting of the vapor stream S XB1 and the n vapor streams S XB(n+1) , where " S XB(n+1) " the respective vapor stream of the rectification column RD x(n+1) designated.

[0200] In the embodiments of the present invention in which more than one column RD X for the separation of S DAS is used, refers to " G X " the group consisting of the mixture G X1 and the n mixtures G X(n+1) , where " G X(n+1) " the respective mixture G X in the rectification column RD x(n+1) designated.

[0201] The at least one component Q 1 In a preferred embodiment of the present invention, is selected from the group consisting of S AE1 , S AE2 , RP A , S AS , G A , S DAS selected, wherein, when step (a2) is carried out, the at least one component Q 1 alternatively or additionally from S BE1 , S BE2 , RP B , S BS can be selected, and wherein, when step (d) is carried out, the at least one component Q 1 alternatively or additionally from G X , S XS can be selected.

[0202] The at least one component Q 1 In a more preferred embodiment of the present invention, is selected from the group consisting of RP A , S AS , G A , S DAS selected, wherein, when step (a2) is carried out, the at least one component Q 1 alternatively or additionally from RP B , S BS can be selected, and wherein, when step (d) is carried out, the at least one component Q 1 alternatively or additionally from G X , S XS can be selected.

[0203] The at least one component Q 1 In an even more preferred embodiment of the present invention, is selected from the group consisting of G A , S DAS selected, and wherein, when step (d) is carried out, the at least one component Q 1 alternatively or additionally from G X , S XS can be selected.

[0204] The at least one component Q 1 is in an even more preferred embodiment of the present invention from the group consisting of G A , S DAS selected.

[0205] The at least one component Q 2 In a preferred embodiment of the present invention, is selected from the group consisting of S AE1 , S AE2 , RP A , S AS , G A , S DAS selected, wherein, when step (a2) is carried out, the at least one component Q 2 alternatively or additionally from S BE1 , S BE2 , RP B , S BS can be selected, and wherein, when step (d) is carried out, the at least one component Q 2 alternatively or additionally from G X , S XS can be selected.

[0206] The at least one component Q 2 In a more preferred embodiment of the present invention, is selected from the group consisting of RP A , S AS , G A , S DAS selected, wherein, when step (a2) is carried out, the at least one component Q 2 alternatively or additionally from RP B , S BS can be selected, and wherein, when step (d) is carried out, the at least one component Q 2 alternatively or additionally from G X , S XS can be selected.

[0207] The at least one component Q 2 In a further preferred embodiment of the present invention, is selected from the group consisting of G A , S DAS selected, and wherein, when step (d) is carried out, the at least one component Q 2 alternatively or additionally from G X , S XS can be selected.

[0208] The at least one component Q 2 is in an even more preferred embodiment of the present invention from the group consisting of G A , S DAS selected.

[0209] The energy of the heating steam H 1 or H 4 can be applied in step (e) or step (h) of the process according to the invention to the at least one component using methods known to the person skilled in the art Q 1 or Q 2 For this purpose, a heat exchanger is used WT used as heat exchangers WT (also referred to as "heat exchanger"), all heat exchangers familiar to the person skilled in the art can be used for this purpose. This is preferably an evaporator, preferably selected from the group consisting of a sump evaporator VS, an intermediate evaporator VZ.

[0210] The energy transfer from the heating steam H 1 or H 4 to which at least one component Q 1 or Q 2 According to the invention, this is achieved in particular by the fact that the heating steam H 1 or H 4 Heat to at least one component Q 1 or Q 2 is transferred, the heating steam H 1 or H 4 that is, at least one component Q 1 or Q 2 heated.

[0211] The energy transfer from the heating steam H 1 to which at least one component Q 1 This occurs in particular directly or indirectly.

[0212] The energy transfer from the heating steam H 4 to which at least one component Q 2 This occurs in particular directly or indirectly.

[0213] "Direct" means in the case of H 1 and Q 1 , that H 1 with at least one component Q 1 contacted, so that energy, preferably heat, is transferred from H, to which at least one component Q, The contact is preferably made in a heat exchanger WT, even more preferably in an evaporator.

[0214] In case of H 4 and Q 2 "direct" means that H 4 with at least one component Q 2 contacted, so that energy, preferably heat, is transferred from H 4 to which at least one component Q 2 The contacting preferably takes place in a heat exchanger (WT), even more preferably in an evaporator.

[0215] It goes without saying that both "direct" and "indirect" energy transfer H, and Q 1 or H 4 and Q 2 or H, or H 4 and W 1 Do not mix, as then no condensate K 1 or K 2 Contacting without mixing is achieved by methods known to those skilled in the art, for example by contacting via a partition made of metal, plastic, etc., especially in the heat exchanger WT.

[0216] In case of Q 1 or Q 2 to S AE1 The direct energy transfer from H 1 or H 4 on S AE1 in particular by S AE1 and H 1 or H 4 through a heat exchanger WT (e.g. <wa4>in Figures 1 to 4) before S AE1 into the reaction column RR A is directed so that S AE1 the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S AE1 is transferred.

[0217] In case of Q 1 or Q 2 to S AE2 The direct energy transfer from H 1 or H 4 on S AE2 in particular by S AE2 and H 1 or H 4 through a heat exchanger WT (e.g. <wa5>in Figures 1 to 4) before S AE2 into the reaction column RR A is directed so that S AE2 the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S AE2 is transferred.

[0218] In case of Q 1 or Q 2 to RP A The direct energy transfer from H 1 or H 4 on RP A in particular by RP A as electricity S RRAZ from the column RR A is managed and S RRAZ and H 1 or H 4 via a heat exchanger WT, preferably an intermediate evaporator VZ RRA (e.g. <wa3>in Figures 1 to 4), on the reaction column RR A be directed so that S RRAZ the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S RRAZ is transferred. After that, S RRAZ for the rest RP A in RR A returned.

[0219] In case of Q 1 or Q 2 to S AS The direct energy transfer from H 1 or H 4 on S AS in particular by S AS and H 1 or H 4 through a heat exchanger WT, preferably a sump evaporator VS RRA (e.g. <wa1>in Figures 1 to 4), on the reaction column RR A be directed so that S AS the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S AS is transferred.

[0220] In case of Q 1 or Q 2 to S AB The direct energy transfer from H 1 or H 4 on S AB in particular by S AB and H 1 or H 4 through a heat exchanger WT (e.g. <wa6>in Figures 1 to 4) so ​​that S AB the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S AB is transferred.

[0221] In case of Q 1 or Q 2 to G A The direct energy transfer from H 1 or H 4 on G A in particular by G A as electricity S AZ from the column RR A is managed and S AZ and H 1 or H 4 via a heat exchanger WT, preferably an intermediate evaporator VZ A (e.g. <w9>in Figures 1 to 4), on the rectification column RD A be directed so that S AZ the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S AZ is transferred. After that, S AZ for the rest G A in RD A returned.

[0222] In case of Q 1 or Q 2 to S DAS The direct energy transfer from H 1 or H 4 on S DAS in particular by S DAS and H 1 or H 4 by a

[0223] heat exchanger WT, preferably a sump evaporator VS A (e.g. <w7>in Figures 1 to 4), on the rectification column RD A be directed so that S DAS the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S DAS is transferred.

[0224] In case of Q 1 or Q 2 to S DAB The direct energy transfer from H 1 or H 4 on S DAB in particular by S DAB and H 1 or H 4 through a heat exchanger WT (not shown in the figures) so that S DAB the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S DAB is transferred.

[0225] In case of Q 1 or Q 2 to S BE1 The direct energy transfer from H 1 or H 4 on S BE1 in particular by S BE1 and H, or H 4 through a heat exchanger WT (e.g. <wb4>in Abbildung 4 ) before S BE1 into the reaction column RR B is directed so that S BE1 the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S BE1 is transferred.

[0226] In case of Q 1 or Q 2 to S BE2 The direct energy transfer from H 1 or H 4 on S BE2 in particular by S BE2 and H, or H 4 through a heat exchanger WT (e.g. <wba5>in Abbildung 4 ) before S BE2 into the reaction column RR B is directed so that S BE2 the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S BE2 is transferred.

[0227] In case of Q 1 or Q 2 to RP B The direct energy transfer from H 1 or H 4 on RP B in particular by RP B as electricity S RRBZ from the column RR B is managed and S RRBZ and H 1 or H 4 via a heat exchanger WT, preferably an intermediate evaporator VZ RRB (e.g. <wb3>in Abbildung 4 ), on the reaction column RR B be directed so that S RRBZ the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S RRBZ is transferred. After that, S RRBZ for the rest RP B in RR B returned.

[0228] In case of Q 1 or Q 2 to S BS The direct energy transfer from H 1 or H 4 on S BS in particular by S BS and H 1 or H 4 through a heat exchanger WT, preferably a sump evaporator VS RRB (e.g. <wb1>in Abbildung 4 ), on the reaction column RR B be directed so that S BS the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S BS is transferred.

[0229] In case of Q 1 or Q 2 to S BB The direct energy transfer from H 1 or H 4 on S BB in particular by S BB and H 1 or H 4 through a heat exchanger WT (e.g. <wb6>in Abbildung 4 ) so that S BB the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S BB is transferred.

[0230] In case of Q 1 or Q 2 to G X The direct energy transfer from H 1 or H 4 on G X in particular by G X as electricity S XZ from the column RD X is managed and S XZ and H 1 or H 4 via a heat exchanger WT, preferably an intermediate evaporator VZ X (e.g. <w13>in Abbildung 4 ), at the rectification column RD X be directed so that S XZ the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S XZ is transferred. After that, S XZ for the rest G X in RD X returned.

[0231] In case of Q 1 or Q 2 to S XS The direct energy transfer from H 1 or H 4 on S XS in particular by S XS and H 1 or H 4 through a heat exchanger WT, preferably a sump evaporator VS X (e.g. <w11>in Abbildung 4 ), at the rectification column RD X be directed so that S XS the heating steam H 1 or the heating steam H 4 in the heat exchanger WT and thus energy from H 1 or H 4 on S XS is transferred.

[0232] In case of Q 1 or Q 2 to S XB The direct energy transfer from H 1 or H 4 on S XB in particular by S XB and H 1 or H 4 through a heat exchanger WT (not shown in the figures) so that S XB the heating steam H 1 or the heating steam H 4 in the heat exchanger WT contacted and thus energy from H 1 or H 4 on S XB is transferred.

[0233] "Indirect" means in the case of H 1 and Q 1 that energy from heating steam H 1 on a heat transfer medium W, is transferred, in particular H, with a heat transfer medium W, contacted, so that energy, preferably heat, is transferred from H 1 on W 1 and then the energy from W, to which at least one component Q, The transfer of energy from W 1 on Q 1 can then take place directly or indirectly, that is, in the W, with at least one component Q 1 contacted, so that energy, preferably heat, is transferred from W, to which at least one component Q 1 passes ("directly") or that the energy of W, first to one or more additional heat carriers W 2 , W 3 , W 4 etc. and the last of these heat carriers, referred to as " W Y ", with at least one component Q 1 contacted, so that energy, preferably heat, is transferred from W Y to which at least one component Q, The described contacts preferably take place in a heat exchanger WT, even more preferably in an evaporator.

[0234] In the case of indirect energy transfer from H 1 to which at least one component Q 1 However, it is preferred that H, with a heat transfer medium W, contacted, so that energy, preferably heat, is transferred from H 1 on W 1 and then the energy of W 1 on Q 1 by contacting W, with at least one component Q 1 in a heat exchanger WT is transferred.

[0235] The transfer of energy from W, on Q 1 can be used in the embodiment in which W, a stream which essentially comprises water and / or the alcohol ROH, may also be carried out in such a way that W 1 with at least one component Q 1 is mixed after energy from heating steam H 1 on W 1 , preferably in a heat exchanger WT, This embodiment is particularly advantageous if the at least one component Q 1 from the group consisting of RP A , G A , RP B , G X , preferably from G A , G X , is selected.

[0236] "Stream comprising essentially water and / or alcohol ROH" means, in particular, that the mass fraction of alcohol ROH and water in the stream is ≥ 90 wt.%, preferably ≥ 96 wt.%, ≥ 99 wt.%. More preferably, this means that the ratio of the mass of water comprised in the stream to the mass of alcohol ROH comprised in the stream is less than 1:1, preferably 1:5, more preferably 1:9, more preferably 1:49, even more preferably 1:99, even more preferably 1:999.

[0237] "Indirect" means in the case of H 4 and Q 2 that energy from heating steam H 4 on a heat transfer medium W, is transferred, in particular H 4 with a heat transfer medium W, contacted, so that energy, preferably heat, is transferred from H 4 on W 1 and then the energy from W, to which at least one component Q 2 The transfer of energy from W, on Q 2 can then take place directly or indirectly, that is, in the W, with at least one component Q 2 contacted, so that energy, preferably heat, is transferred from W, to which at least one component Q 2 passes ("directly") or that the energy of W, first to one or more additional heat carriers W 2 , W 3 , W 4 etc. and the last of these heat carriers, referred to as " W Y ", with at least one component Q 2 contacted, so that energy, preferably heat, is transferred from W Y to which at least one component Q 2 The described contacts preferably take place in a heat exchanger, even more preferably in an evaporator.

[0238] In the case of indirect energy transfer from H 4 to which at least one component Q 2 However, it is preferred that H 4 with a heat transfer medium W, contacted, so that energy, preferably heat, is transferred from H 4 on W 1 and then the energy of W, on Q 2 by contacting W, with at least one component Q 2 in a heat exchanger WT is transferred.

[0239] In the embodiment in which W, is a stream that essentially comprises water and / or the alcohol ROH, the indirect transfer of energy from W, on at least one component Q 2 preferably carried out in such a way that W, with at least one component Q 2 is mixed after energy from heating steam H 1 on W 1 , preferably in a heat exchanger WT, This embodiment is particularly advantageous if the at least one component Q 2 from the group consisting of RP A , G A , RP B , G X , preferably from G A , G X , is selected.

[0240] The mixture of W, with at least one component Q 1 or at least one component Q 2 is carried out in particular by W 1 , for example if the component is Q 1 or Q 2 around a stream S AE1 , S AE2 , S AS , S AB , S DAS , S DAB , S BE1 , S BE2 , S BS , S BB , S XB , S XS is the current in the line. If the component is Q 1 or Q 2 to one of the mixtures RP A , G A , RP B , G X acts, can W 1 advantageously be fed into the column in which the mixture in question is located, in the case of RP A also in RR A , in case of RP B also in RR B , in case of G A also in RD A and in case of G X also in RD X .

[0241] According to the invention, W, and all heat transfer media used in indirect energy transfer W 2 , W 3 , W 4 etc. to avoid any of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S XS .

[0242] According to the invention, this also includes the case that W 1 , W 2 , W 3 , W 4 etc. contains the same substances as one of S AE1 , S AE2 , RP A , S AS , S AB , G A , S DAS , S DAB , S BE1 , S BE2 , RP B , S BS , S BB , G X , S XB , S XS , and differs from the stream or mixture only in the mass fractions of the substances.

[0243] As a heat transfer medium W, or, if applicable, additional heat transfer media W 2 , W 3 , W 4 etc., any heat transfer medium known to the person skilled in the art can be used. They are preferably selected from the group consisting of water; alcohols, preferably the alcohol ROH; alcohol-water solutions, preferably ROH-water solutions; salt-water solutions, which also include ionic liquids, such as LiBr solutions, dialkylimidazolium salts such as in particular dialkylimidazolium dialkylphosphates; mineral oils, such as diesel oils; thermal oils such as silicone oils; biological oils such as limonene; aromatic hydrocarbons such as dibenzyltoluene. The most preferred heat transfer medium, in particular as heat transfer medium W, Water, alcohol or alcohol-water solutions are used, wherein the alcohol is preferably the alcohol ROH, wherein the alcohol is the same as that used in step (a1) and optionally in step (a2).

[0244] Salt-water solutions that can be used are also described, for example, in DE 10 2005 028 451 A1 and WO 2006 / 134015 A1.

[0245] This embodiment, in which energy is transferred indirectly, is therefore particularly advantageous when fresh RAW alcohol is to be supplied to the system.

[0246] In the context of the invention, the term "bar" always means "bar absolute" (= "bar abs.").

[0247] H, In particular, it has a temperature T 1 from 101 °C to 270 °C, preferably from 105 °C to 250 °C, preferably 130 °C to 200 °C. H, preferably has a pressure of 1 to 55 bar, preferably 2 to 5 bar, more preferably 4 bar. As heating steam H 1 steam with a pressure of > 30 bar can also be used.

[0248] The heating steam H 1 condenses at least partially during the transfer of energy, whereby preferably a condensate K 1 at a pressure of 1 to 55 bar, preferably 2 to 5 bar, particularly preferably 4 bar and a temperature of 101 °C to 270 °C, preferably 105 °C to 250 °C, preferably 110 °C to 200 °C.

[0249] The heating steam condensate K 1 is preferably collected in a condensate tank. Any container known to the expert can be used for this purpose, e.g., made of steel. 4.7 Schritt (f) des erfindungsgemäßen Verfahrens

[0250] In step (f) of the process according to the invention K 1 at least partially to a heating steam H 2 with pressure p 2 and temperature T 2 is relaxed, whereby p 2 < p 1 .

[0251] The expansion of the heating steam condensate K 1 is preferably carried out in such a way that K 1 into a condensate tank in which the hot condensate can be separated from the steam. In a preferred embodiment of the process according to the invention, K 1 used to heat streams and / or mixtures in the process before it becomes a heating steam H 2 Likewise, the remaining condensate, which after relaxation to p 2 remaining in the liquid state can be used to heat streams and / or mixtures in the process.

[0252] The pressure in the condensate tank is preferably lower than in the heat exchanger (in which H, at least partially condensed) on the heating steam side. Due to the lower pressure, part of the hot condensate K 1 evaporate, whereby the entire steam, ie the non-condensed portion of the heating steam and the hot condensate evaporated in the condensate tank by pressure relief, is stored in the condensate tank as heating steam H 2 This heating steam H 2 is in particular low-pressure steam and preferably has a pressure p 2 for which the quotient p 2 / p 1 (bar / bar) in the range 0.001 to 0.999, preferably 0.01 to 0.9, more preferably 0.05 to 0.8, more preferably 0.1 to 0.7, more preferably 0.15 to 0.6, more preferably 0.2 to 0.5.

[0253] In another preferred embodiment, the temperature T 2 from H 2 below the temperature T 1 from H 1 . It is then preferable that T 2 > 0 °C, and the quotient of temperature T 2 / T 1 (°C / °C) is in the range 0.1 to 0.999, more preferably 0.2 to 0.995, more preferably 0.3 to 0.990.

[0254] The condensate K 1 can be formed in addition to the condensation of H 1 The resulting condensate may be composed of other heating steam condensates, for example when different heating steams are used in the process according to the invention and thus to different components Q 1 Energy is transferred from different heating vapors. In this configuration, several condensates are produced K 1 which can be combined and in step (f) to form heating steam H 2 be relaxed.

[0255] Such a preferred embodiment is, for example, in Abbildung 3 shown. The condensate tank <86> collected condensate K 1 is a mixture of condensates <71> and <81> and additionally <88> . The condensate <81> results from the condensation of the heating steam <84> in energy transfer to G A in the intermediate evaporator VZ A <w9>. The condensate <71> results from the condensation of the heating steam <74> in energy transfer to G A in the bottom evaporator VS A <w8>.

[0256] The hot condensates from these two evaporators are then transferred to a condensate tank as described above <86> The heating steam generated there H 2 <82> is then in the adjustable steam jet <89> used, whose mixed steam is used as new heating steam H 4 <84> again in the intermediate evaporator VZ A <w9>The advantage of this variant is that the resulting hot condensate can be further expanded to provide a larger amount of low-pressure steam.

[0257] Abbildung 4 shows a corresponding routing of the condensate and heating steam flows at the rectification column RD X <3> . 4.8 Schritt (g) des erfindungsgemäßen Verfahrens

[0258] In step (g) of the process according to the invention H 2 with additional heating steam H 3 with pressure p 3 and temperature T 3 mixed so that a mixed heating steam H 4 with pressure p 4 and temperature T 4 is obtained, where p 2 < p 4 < p 3 and in particular p 1 < p 3 .

[0259] The condensate K 1 and thus the heating steam H 2 still contains energy that is not utilized in any known process for the production of alkali metal alkoxides. However, from an energetic and economic perspective, this is not feasible. This energy can be utilized within the scope of the present invention.

[0260] The mixture of H 2 with additional heating steam H 3 can be carried out using any method known to the person skilled in the art, in particular by combining the two heating vapors using a Venturi nozzle.

[0261] In a preferred embodiment of the process according to the invention, the steam H 2 with additional steam, which creates a pressure p < p 3 has, mixed, and the resulting steam with H 3 mixed.

[0262] The preferred mixture is H 2 with additional heating steam H 3 by means of a steam jet, preferably an adjustable one DS (thermocompressor). The thermocompressor is then supplied with additional heating steam H 3 , which comes, for example, from a corresponding steam network, as well as with the low-pressure steam H 2 fed from the condensate tank, creating a mixed steam H 4 which is the heat transfer medium. In this configuration, the mixed steam is therefore the heating steam H 4 .

[0263] Such a steam cleaner DS is in Abbildung 5 It is designed to operate with motive steam at a higher pressure level and to draw in suction steam at a lower pressure level, which then creates the mixed steam used as a heat transfer medium. In this case, the motive steam is the heating steam or motive steam. H 3 , with which the heating steam H 2 as suction steam from the condensate tank and with the motive steam H 3 is mixed.

[0264] The advantage of such a design is obvious. Part of the energy of the low-pressure steam accumulating in the condensate tank can be utilized, thus saving energy and costs. Such a procedure can also be advantageous for another reason. The steam jet used can be adjustable so that the amount of medium-pressure steam H 3 and low-pressure steam H 2 , for example, depending on certain process parameters. The suction steam quantity is adjusted via the motive steam quantity. The quantities of medium-pressure steam H 3 and low-pressure steam H 2 can, for example, depend on the temperature of at least one component Q 1 be set.

[0265] The pressure p 3 of the heating steam H 3 is larger than p 2 and can otherwise be selected within a wide range. The invention is particularly suitable for situations where heating steam H 3 which has little influence on the pressure and temperature and which is then reduced to a given value H 4 should be set. Therefore, p 2 < p 4 < p 3 .

[0266] In a particular embodiment of the method according to the invention, in particular when Q 1 and Q 2 are equal, p 2 < p 1 < p 3 .

[0267] The heating steam used H 3 prefers a print p 3 in the range of 2 bar to 80 bar, preferably a temperature T 3 from 120 °C to 300 °C, while at the same time p 4 < p 3 and preferably also p 1 < p 3 are. 4.9 Schritt (h) des erfindungsgemäßen Verfahrens

[0268] In step (h) energy from heating steam H 4 with pressure p 4 and temperature T 4 on at least one component Q 2 transmitted.

[0269] The meaning of the component Q 2 is defined above in the context of step (e), section 4.6.

[0270] In a preferred embodiment of the present invention, the heating steam condenses H 4 at least partially and a condensate is formed K 2 is received.

[0271] H 4 In particular, it has a temperature T 4 from 101 °C to 270 °C, preferably from 105 °C to 250 °C, preferably 110 °C to 200 °C. H 4 preferably has a pressure of 1 to 55 bar, preferably 2 to 5 bar, more preferably 4 bar. As heating steam H 4 steam with a pressure of > 30 bar can also be used.

[0272] The heating steam H 4 condenses at least partially, especially during the transfer of energy, whereby preferably a condensate K 2 at a pressure of 1 to 55 bar, preferably 2 to 5 bar, particularly preferably 4 bar and a temperature of 101 °C to 270 °C, preferably 105 °C to 250 °C, preferably 110 °C to 200 °C.

[0273] The heating steam condensate K 2 is preferably collected in a condensate tank. Any condensate tank known to those skilled in the art can be used for this purpose, e.g., steel tanks.

[0274] The advantage of the present invention is, inter alia, that the sequence of steps (f), (g), (h) can be carried out in a cycle, and the subsequent step (h) by the at least partial condensation of H 4 accumulating condensate K 2 again as condensate K 1 in a new round from step (f), (g), (h).

[0275] This is especially advantageous when Q 1 and Q 2 are equal.

[0276] In a preferred embodiment of the present invention, the heating steam H 4 at least partially condensed and thus a condensate K 2 obtained, with which, following step (h), a further step (f) is carried out in which the condensate K 2 then as condensate K 1 is used.

[0277] This allows the process according to the invention to be carried out continuously and the heating of the corresponding component Q 1 and Q 2 in the cycle.

[0278] In the process according to the invention, preferably p 1 and p 4 , ie the ratio of p 1 / p 4 is preferably in the range 0.5 to 1.5, more preferably 0.8 to 1.2, more preferably 0.9 to 1.1, even more preferably 0.99 to 1.01, most preferably 1. 5. Beispiele 5.1 Example (not according to the invention)

[0279] Comparative Example 1 is carried out in an apparatus according to Figure 1 carried out.

[0280] A stream of aqueous NaOH S AE2 <1A2> (48.5 wt.% NaOH, 51.5 wt.% water) of 459 kg / h is added at room temperature to the top of a reaction column RR A <1A> with head pressure of 1.6 bar abs.

[0281] In countercurrent, a vaporous methanol stream S AE1 <1A1>, which has low water impurities, is fed at a rate of 6962 kg / h via the bottom of the reaction column <1A>.

[0282] At the top of the reaction column, a methanol-water mixture S AB <1A5>, of which 551 kg / h are condensed via a condenser and recycled to the column <1A> (not shown in the figures), and 6421 kg / h further via a compressor VD31 <11> to the column RD A <2> be directed.

[0283] At the swamp of the column RR A <1A> a nearly water-free product stream S AS <1A4> from the column. From this, 1000 kg / h are discharged from the process as a product stream. The remaining portion is fed to the bottom evaporator V SRRA. <wa1>294 kg / h of heating steam (11 bar abs., 190°C) are fed through a control valve <85> to 4 bar abs. and thus via the sump evaporator VS RRA <wa1>Energy on this part of the withdrawn current S AS <1A4>, whereby the heating steam condenses and the extracted product stream S AS

[0284] <1A4> partially evaporated and thus the desired MeOH content in the bottom product S AS <1A4> is set.

[0285] The non-condensed part of the head stream S AB <1A5> (6421 kg / h MeOH / water mixture) is supplied via compressor VD31 <11> (Outlet pressure 2.25 bar abs.) into the rectification column RD A <2> (head pressure from column RD A <2> = 2.2 bar abs.).

[0286] At the top of the rectification column RD A <2> a pressure difference is created between the inlet and the compressor VD31 <11> methanol-water mixture enriched with methanol S DAB <24> additionally 878 kg / h of fresh methanol <25> at the head of the column on the column RD A <2> At the bottom of the rectification column RD A <2> a stream enriched with water compared to the column feed from the compressor is obtained S THAT <22> Part of this stream is transferred via the sump evaporator VS A <w8>into the column <2> recycled, with the remaining 337 kg / h being discharged as bottom product stream.

[0287] For the operation of the sump evaporator VS A <w8>3256 kg / h of heating steam (11 bar abs., 190°C) are supplied via a control valve <85> to 4 bar abs. and via the sump evaporator VS A <w8>Energy is transferred to the recirculated stream, whereby the heating steam condenses.

[0288] The heating steam condensate streams from <wa1>and <w8>are stored in a condensate tank <86> For return to the condensate network, the escaping condensate stream <87> of approximately 143°C with cooling water at 75°C. Approximately 285 kW is transferred to the cooling water. 5.2 Example 2 (according to the invention)

[0289] Example 2 is carried out in an apparatus according to Figure 2 carried out.

[0290] This is a repetition of Example 1 with the following differences: The collected condensate in the condensate tank <86> is expanded to 1.5 bar abs. Approximately 217 kg / h of condensate evaporates <82> . The heating steam <83> is not controlled by a control valve <85> relaxed, but as motive steam for an adjustable steam jet <89> used to generate electricity <82> to suck in and with <83> to mix. At the exit of <89> you get the heating steam <84> at 4 bar abs. By using additional heating steam from the expansion of the condensate, only 3048 kg / h of fresh heating steam <83> for the operation of the sump evaporator VSA <w8>needed.

[0291] This results in a current <84> (approximately 3265 kg / h), which when operating the sump evaporator V SA <w8>as condensate <81> condensed. The resulting condensate stream <81> is then returned to the condensate tank <86> initiated.

[0292] The condensate flow <87> only occurs at a temperature of approximately 111 °C. Thus, less cooling water is required to cool to 75 °C than in Example 1, and only approximately 142 kW is transferred to the cooling medium, i.e., only 50% of the amount required in Example 1.

[0293] In total, in the procedure according to Example 2, only 3342 kg / h of heating steam (11 bar abs, 190°C) are used as heating steam for <wa1>and <wa8> Compared to Example 1, this allows approximately 6% of the 11 bar absolute heating steam to be saved.< / wa8> < / w9> < / w8> < / w9> < / w7> < / wa6> < / w9> < / w7> < / wa6> < / w9> < / w7> < / wa6>

Claims

1. Process for producing at least one alkali metal alkoxide of the formula MAOR, where R is a C1-C6 hydrocarbon radical and MA is selected from sodium, potassium, where: (a1) a feed stream SAE1 comprising ROH is reacted with a feed stream SAE2 comprising MAOH in countercurrent in a reactive rectification column RRA to give a crude product mixture RPA comprising MAOR, water, ROH, MAOH, where a bottom product stream SAS comprising ROH and MAOR is taken off at the lower end of RRA and a vapour stream SAB comprising water and ROH is taken off at the upper end of RRA, (a2) and optionally, simultaneously with and spatially separately from step (a1), a feed stream SBE1 comprising ROH is reacted with a feed stream SBE2 comprising MBOH in countercurrent in a reactive rectification column RRB to give a crude product mixture RPB comprising MBOR, water, ROH, MBOH, where MB is selected from sodium, potassium, where a bottom product stream SBS comprising ROH and MBOR is taken off at the lower end of RRB and a vapour stream SBB comprising water and ROH is taken off at the upper end of RRB, (b) the vapour stream SAB, and, when step (a2) is carried out, the vapour stream SBB, mixed with SAB or separately from SAB, is introduced into a rectification column RDA so that a mixture GA comprising water and ROH is present in RDA, (c) and GA is separated in RDA into a vapour stream SDAB comprising ROH at the upper end of RDA and a bottom stream SDAS comprising water and ROH at the lower end of RDA, where the bottom stream SDAS is discharged from RDA at an offtake point EAS at the lower end of RDA and the vapour stream SDAS is discharged from RDA at an offtake point EAK at the upper end of RDA, (d) and optionally SDAS is, in its entirety or partly, separated in at least one rectification column RDX which is different from RDA and in which a mixture Gx comprising water and ROH is then present into a vapour stream SXB comprising ROH at the upper end of RDX and a bottom stream Sxs comprising water and optionally ROH at the lower end of RDX, where the bottom stream Sxs is discharged from the at least one rectification column RDX at an offtake point EXS at the lower end of this column and the vapour stream SXB is discharged from the at least one rectification column RDX at an offtake point EXK at the upper end of this column, (e) energy is transferred from a heating vapour H1 having a pressure p1 to at least one component Q1, as a result of which the heating vapour H1 condenses at least partially and a condensate K1 is thus obtained, characterized in that (f) K1 is at least partially depressurized to give a heating vapour H2 having a pressure p2, where p2 < p1, (g) H2 is mixed with further heating vapour H3 having a pressure p3 so as to give a heating vapour H4 having a pressure p4, where p2 < p4 < p3, (h) energy is transferred from H4 to at least one component Q2, where Q1 and Q2 are identical or different from one another, and where Q1 and Q2 are selected from the group consisting of SAE1, SAE2, RPA, SAS, SAB, GA, SDAS, SDAB, and where Q1 and Q2 can, when step (a2) is carried out, alternatively or additionally be selected from the group consisting of SBE1, SBE2, RPB, SBS, SBB, and where Q1 and Q2 can, when step (d) is carried out, alternatively or additionally be selected from the group consisting of GX, SXB, SXS.

2. Process according to Claim 1, wherein the heating vapour H1 is contacted with the at least one component Q1 so that energy is transferred from H1 to the at least one component Q1 and the heating vapour H4 is contacted with the at least one component Q2 so that energy is transferred from H4 to the at least one component Q2.

3. Process according to Claim 1, wherein energy is transferred from heating vapour H1 to a heat transfer medium W1 and the energy of W1 is subsequently transferred to the at least one component Q1 and energy from heating vapour H4 is transferred to W1 and energy is subsequently transferred from W1 to the at least one component Q2, where W1 is none of SAE1, SAE2, RPA, SAS, SAB, GA, SDAS, SDAB, SBE1, SBE2, RPB, SBS, SBB, GX, SXB, SXS.

4. Process according to Claim 3, wherein W1 comprises essentially water and / or alcohol ROH.

5. Process according to Claim 4, wherein the transfer of energy from W1 to the at least one component Q1 or Q2 occurs by W1 being mixed at least partly with Q1 or Q2 after energy has been transferred from heating vapour H1 or H4 to W1.

6. Process according to any of Claims 1 to 5, wherein R is selected from methyl, ethyl.

7. Process according to any of Claims 1 to 6, wherein p1 < p3.

8. Process according to any of Claims 1 to 7, wherein Q1 and Q2 are identical.

9. Process according to any of Claims 1 to 8, wherein the heating vapour H4 is at least partially condensed so as to give a condensate K2 by means of which a further step (f) in which the condensate K2 is then used as condensate K1 is carried out after step (h).

10. Process according to any of Claims 1 to 9, wherein the ratio of p1 / p4 is in the range from 0.5 to 1.5.

11. Process according to any of Claims 1 to 10, wherein at least part of the vapour stream SAB taken off at the offtake point EAK at the upper end of the rectification column RDA is fed to the reaction column RRA at least as part of the feed stream SAE1 and, in cases in which step (a2) is carried out in the process of the invention, is alternatively or additionally fed to the reaction column RRB at least as part of the feed stream SBE1.

12. Process according to any of Claims 1 to 11, wherein step (d) is carried out.

13. Process according to Claim 12, wherein at least part of the vapour stream SXB taken off at the offtake point EXK at the upper end of the at least one rectification column RDX is fed to the reaction column RRA at least as part of the feed stream SAE1 and, in cases in which step (a2) is carried out in the process of the invention, is alternatively or additionally fed to the reaction column RRB at least as part of the feed stream SBE1.

14. Process according to any of Claims 1 to 13, wherein step (a2) is carried out.

15. Process according to any of Claims 1 to 14 which is carried out continuously.