CN103896840A - Method and equipment for continuously producing epsilon-caprolactam - Google Patents
Method and equipment for continuously producing epsilon-caprolactam Download PDFInfo
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- CN103896840A CN103896840A CN201210589758.4A CN201210589758A CN103896840A CN 103896840 A CN103896840 A CN 103896840A CN 201210589758 A CN201210589758 A CN 201210589758A CN 103896840 A CN103896840 A CN 103896840A
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- beckmann rearrangement
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- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/02—Preparation of lactams
- C07D201/04—Preparation of lactams from or via oximes by Beckmann rearrangement
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/24—Sulfates of ammonium
- C01C1/242—Preparation from ammonia and sulfuric acid or sulfur trioxide
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
- C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
- C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
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- C07D223/10—Oxygen atoms attached in position 2
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Abstract
The invention provides a method and equipment for continuously producing epsilon-caprolactam. The method orderly comprises the following steps: a) inputting i) fuming sulphuric acid and/or ii) cyclohexanone-oxime into a beckmann rearrangement reaction zone; b) discharging the generated mixture containing epsilon-caprolactam from the beckmann rearrangement reaction zone; c) adding ammonia to the mixture containing the epsilon-caprolactam; d) separating out ammonium sulfate from the mixture containing the epsilon-caprolactam; e) extracting the epsilon-caprolactam from the mixture containing the epsilon-caprolactam in an organic solvent; and f) adding water to remove an organic solvent from the extracted epsilon-caprolactam in a distillation zone by using distillation. The method is characterized in that at least one part of reaction heat generated in the beckmann rearrangement reaction zone is exchanged to the distillation zone. The invention also provides equipment for executing the method and the epsilon-caprolactam obtained according to the method.
Description
Technical field
The method that the present invention relates to produce ε-caprolactam and reclaim this ε-caprolactam in the mode of high energy efficiency from organic solution.
Background technology
In the method for preparing ε-caprolactam, conventionally need to from the solution that contains the ε-caprolactam that is dissolved in organic solvent, reclaim ε-caprolactam, in described method, cyclohexanone-oxime is converted into ε-caprolactam by acid.Described conversion is called as Beckmann rearrangement.Beckmann rearrangement is the reaction of height heat release, and is therefore conventionally subject to the control of cooling system.After rearrangement reaction occurs, can be by alkali, preferably ammonia, can join the Beckmann rearrangement mixture that produces neutralization in Beckmann rearrangement mixture.Remove ammonium sulfate and in organic solvent, extract remaining ε-caprolactam.Organic solvent must be removed by distillation.Object is in rearrangement of cyclohexanone-oxime reaction, and cyclohexanone-oxime is converted into as far as possible fully ε-caprolactam and transforms with the mode of environmental protection and economy abundant as far as possible and as far as possible pure isolating by cyclohexanone-oxime from conversion reaction thing the ε-caprolactam forming simultaneously.
WO02/070475 has described a kind of method of purifying ε-caprolactam, and the loss of ε-caprolactam is followed seven step flow processs and can be reduced in its elaboration.Wherein said step b) relates under the existence of water and distilling, and benzene and water azeotropic, remove benzene.The ε-caprolactam product producing is in aqueous mixture; This product anhydrates subsequently to process and generates the ε-caprolactam that concentration is 99.5wt.%.Implement further distillation for removing residual moisture and lower boiling organic impurity; The ε-caprolactam of separation and purification; And using high-boiling-point impurity as residue.
DE1194863 described a kind of in two-step method purity ring hexanone oxime carry out the method for the ε-caprolactam of Beckmann rearrangement generation.Crude epsi-caprolactam extracts in benzene.The amount of described benzene must be at least three times of ε-caprolactam amount, is preferably the amount of 4.5-12 ε-caprolactam doubly.This makes ε-caprolactam solution contain 5-15wt.% ε-caprolactam.Subsequently, utilize distillation to remove benzene until remaining mixture contains 25wt.% benzene.Then add aqueous caustic soda solution and distill out remaining benzene.Distillation occurs in single-action or multiple-effect tower also not mentioned.Volume does not provide yet, and therefore embodiment is laboratory pattern or industrial model unclear.
The drawback of art methods is to have expended a large amount of energy in distillation zone.General distillation is multi-step.Steam in this distillation zone of condensation in one or more reboilers can obtain the distillating method institute energy requirement of this single stage or multi-step.Target of the present invention is to reduce the external energy that distillation zone consumes.
The present inventor surprisingly finds, it is possible in a certain way heat being exchanged to distillation zone from Beckmann rearrangement district, has wherein produced highly purified ε-caprolactam.According to the present invention, the heat that Beckmann rearrangement district is produced recycles effectively in distill the method for organic solvent from ε-caprolactam in.
Summary of the invention
Therefore, the invention provides a kind of method of continuous production ε-caprolactam, the method contains in order,
A) by i) oleum and/or sulfuric acid and ii) cyclohexanone-oxime is input to Beckmann rearrangement district;
B) mixture containing ε-caprolactam producing is discharged from Beckmann rearrangement district;
C) ammonia is joined to the mixture containing ε-caprolactam;
D) from isolating ammonium sulfate containing the mixture of ε-caprolactam;
E) in organic solvent, from contain the mixture of ε-caprolactam, extract ε-caprolactam;
F) add water conservancy distillation and from the ε-caprolactam of extraction, remove organic solvent in distillation zone;
Be characterised in that the reaction heat that at least part of Beckmann rearrangement district is produced exchanges to distillation zone.
The present invention also provides the applicable equipment that carries out described method, and this equipment contains a Beckmann rearrangement district and a distillation zone; Be characterised in that described equipment contains one or more heat exchangers that are designed to heat to be exchanged to from Beckmann rearrangement district distillation zone.
Further, the invention provides the ε-caprolactam obtaining according to described method.
Method of the present invention is useful especially, because need less water coolant to reduce the temperature in Beckmann rearrangement district.In addition, need less external heat source to remove the organic solvent of distillation zone.Reduce the heat rejection of external heat source and reduce the requirement of water coolant to mean again the reduction of cost and reducing environmental influence.
The mixture containing ε-caprolactam of generation used herein also contains impurity, for example ammonium sulfate, water and high boiling point and lower boiling organic composition conventionally.These impurity are the feature of ε-caprolactam production method normally.Conventionally, after sulfuric acid and ammonia react, obtained a two-phase system (the aqeous ε-caprolactam phase of aqueous ammonium sulfate).Adopt the method for any suitable separation two-phase can realize from separating ammonium sulfate containing the mixture of ε-caprolactam.
Conventionally adopt organic solvent adverse current is realized to the extraction in organic solvent by counter-current extraction tower.Water and water-soluble impurity are discharged from extraction tower, and further processing.
One or more distillation towers are contained in distillation zone.But it contains one or two distillation tower conventionally.Each distillation tower may comprise column plate or filler or their combination.
Before distillation or during distillation, can add water.For example during distilling, water can be used as phegma.This means to distillation tower tower top and add liquid water.Backflow guarantees that the ε-caprolactam of low ratio is distilled out at tower top.
In one embodiment of the invention, adopt intermediate heat transfer that heat is exchanged to distillation zone from Beckmann rearrangement district.Intermediate heat transfer be Beckmann rearrangement district heating and in distillation zone cooling liquid.Or intermediate heat transfer can be at least part of at the evaporation of Beckmann rearrangement district and liquid can part in distillation zone cooling, partial condensation.For averting misconceptions, the non-reactive component of described intermediate heat transfer; But the component of another.Therefore described intermediate heat transfer is positioned in the middle of two heat exchangers.
In another embodiment of the invention, heat is exchanged to distillation zone and do not adopt intermediate heat transfer from Beckmann rearrangement district.But be delivered to distillation zone by heat exchanger wall from Beckmann rearrangement district.For realizing this point, the mixture containing ε-caprolactam that step a) is produced is transferred to distillation zone from Beckmann rearrangement district; Or by step f) in distillation organic solvent in ε-caprolactam transfer to Beckmann rearrangement district from distillation zone; Or both are all transferred to another one district.
What conventionally step a) is produced in this embodiment, passes through the second Room of heat exchanger containing the mixture of ε-caprolactam by the ε-caprolactam in the first Room of in-process heat exchanger and the organic solvent that will distill in f) in step.
Heat exchanger is that heat is exchanged to the equipment one other fluid steam from a fluid steam.Heat exchanger directly (wherein mixes fluid steam) or indirectly (wherein keeps fluid steam to separate by divider wall).In-process heat exchanger is an indirect heat exchanger, wherein from the process fluid of present method part by thermal exchange in the process liquid of present method another part.The ε-caprolactam of extraction f) distills and advances into in-process heat exchanger in step, and the temperature of the mixture containing ε-caprolactam that step a) produces is higher than the ε-caprolactam of the extraction of f) distilling in step.
In-process heat exchanger contains at least two chambers with divider wall.In its simplest form, in-process heat exchanger contains two Room.By divider wall, heat is exchanged in the fluid of the second Room from the fluid of the first Room.Therefore, there is not intermediate heat transfer.Each chamber has respectively a long path, and has larger surface-to-volume ratio to promote heat transfer.Indirect heat exchanger is known to the skilled person.The example that is applicable to in-process heat exchanger of the present invention is shell-and-tube, board-like and tubular type.Conventionally, in-process heat exchanger is plate indirect heat exchanger.Preferably plate indirect heat exchanger, because it can be processed larger streamer and allow less log-mean temperature difference (LMTD) between heat transfer liquids.
The peculiar advantage arranging is like this when the efficiency ratio of heat exchange adopts intermediate heat transfer high.Therefore, a) produce for step containing the mixture of ε-caprolactam to fixed temperature, can by step f) in ε-caprolactam in the organic solvent of distillation higher temperature while being heated to than employing intermediate heat transfer.Generally, in the time carrying out Beckmann rearrangement at a lower temperature with " being dried " cyclohexanone-oxime, this is very favorable." be dried " cyclohexanone-oxime and refer to there is the cyclohexanone-oxime compared with low water content.Utilize any cyclohexanone-oxime production technology may be able to prepare " dry " cyclohexanone-oxime, but conventionally adopt ammonia oxidation technology and
technology is prepared.In ammonia oxidation technology, utilize hydrogen peroxide and ammonia that pimelinketone is converted into cyclohexanone-oxime.During reclaiming the cyclohexanone-oxime producing, remove water.?
in technology, be to react the azanol that generates cyclohexanone-oxime with pimelinketone by nitrate or conversion of nitrogen oxides.At the dry cyclohexanone-oxime producing in the downstream of purification process.
Add water to the distillation zone that step f) defines.Preferably, water is added as phegma in f) in step.Preferably, the water adding is the water that purity is greater than 99.5wt.%.Conventionally, the distillation tower and the distillation tower of at least one water as phegma of at least one use organic solvent as phegma contained in distillation zone.Refer to organic phase is turned back to distillation tower tower top organic solvent as phegma.Refer to water is turned back to distillation tower tower top water as phegma.In each situation, reflux and guarantee that the ε-caprolactam of low ratio is distilled out at tower top.
Conventionally the reaction heat that, at least part of Beckmann rearrangement district produces is switched in the distillation tower of organic solvent as phegma.Conventionally the distillation tower using organic solvent as phegma is first distillation tower in distillation zone.Normally in distillation zone one of energy consumption maximum of first distillation tower.Conventionally, the column bottom temperature of first distillation tower is that in distillation tower, column bottom temperature is minimum.This temperature difference between just meaning at the bottom of the reaction mixture in Beckmann rearrangement district and the first distillation tower tower is for maximum.Therefore,, compared with distillation tower below, heat can be exchanged in the first distillation tower most effectively.
Conventionally the reaction heat that, at least part of Beckmann rearrangement district produces is switched in the reboiler of organic solvent as the distillation tower of phegma.Suitable reboiler is known to the skilled person.
Conventionally reboiler is heat exchanger, and it can be used for providing heat to distillation tower bottom.Reboiler is by the liquid heat from base product portion, and this liquid turns back in tower subsequently to promote distillation.In addition, reboiler may be incorporated into distillation tower bottom.In typical conventional column, each distillation tower has one or more reboilers and with external heat source, for example steam, starts reboiler.In the present invention, each distillation tower has one or more reboilers.The heat that the exchange of Beckmann rearrangement district is come is for starting the reboiler of at least one distillation zone.In the time having more than one reboiler, the heat that the exchange of Beckmann rearrangement district comes can be used for starting one or more reboilers, and external heat source, and for example steam, can be used to start remaining reboiler.Reboiler is tower bottom reboiler (wherein regaining liquid at the bottom of distillation tower tower); Or it is side reboiler (wherein regaining liquid from distillation tower one side).
Organic solvent can be any suitable type.But conventionally, organic solvent is benzene or toluene.
Conventionally, exchange to before distillation zone at the reaction heat that at least part of Beckmann rearrangement district is produced, the mixture containing ε-caprolactam leaving from Beckmann rearrangement district has the temperature of 75 DEG C to 140 DEG C.
Conventionally, adopting the distillation tower column bottom temperature that organic solvent is phegma is 50 DEG C to 130 DEG C.Preferably, be 60 DEG C to 100 DEG C; It is more preferably 70 DEG C to 90 DEG C.
Conventionally, adopting the distillation tower tower top pressure that organic solvent is phegma is that 20kPa is to 100kPa.Preferably, for 40kPa is to 80kPa; More preferably for 50kPa is to 70kPa.
Beckmann rearrangement district is by more than one, and for example three, Beckmann rearrangement level forms.Conventionally, in prior art, by three independently heat transfer unit by three-heat exchanges that level Beckmann rearrangement district produces are in water coolant.
Implement three-level Beckmann rearrangement district with continuous pattern.Each level contains a recycle system; A mixing equipment; A collection container; A pump; And heat exchanger.Cyclohexanone-oxime is joined in the mixture equipment of the first step.To the first cyclic reaction mixture input sulfuric acid and SO
3(oleum).Part the first mixture containing ε-caprolactam is regained and is entered into the mixing equipment of the second stage from the first collection container.Cyclohexanone-oxime is also added in the mixing equipment of the second stage.Part the second mixture containing ε-caprolactam is regained and is entered into the mixing equipment of the third stage from the second collection container.Cyclohexanone-oxime is also added in the mixing equipment of the third stage.Part the 3rd mixture containing ε-caprolactam is regained from the 3rd collection container.The mixture containing ε-caprolactam that the Beckmann rearrangement district third stage obtains leaves from Beckmann rearrangement district.Described system is as described in WO2004/103964.In the method for the invention, conventionally, the reaction heat that Beckmann rearrangement district has a higher level and Beckmann rearrangement district generation is at least partly to produce in the first step.
As mentioned above, the inventive method is especially applicable to producing ε-caprolactam from " being dried " cyclohexanone-oxime.Preferably, described method also contains the cyclohexanone-oxime that utilizes in hydroxylamine sulfate buffering system pimelinketone and azanol reaction preparation to join Beckmann rearrangement district; Or utilize ammoxidation of cyclohexanone.
Conventionally, present method contains, in another distillation zone, and the water in the ε-caprolactam that removal step f) produces.The ε-caprolactam can drying step f) producing due to this distilation steps.Not necessarily complete drying.Conventionally, residue is lower than the water of 0.2wt.%.Preferably, residue is lower than the water of 0.1wt.%.
Brief description of the drawings
The present invention is by more fully explaining with figure below.
Fig. 1 has described the continuation method that a kind of cyclohexanone-oxime based on being made up of pimelinketone is prepared ε-caprolactam.Fig. 2 has described one embodiment of the invention, wherein prepares in the continuation method of ε-caprolactam at the cyclohexanone-oxime based on being made up of pimelinketone, and heat is to exchange to distillation zone from Beckmann rearrangement district.Fig. 3 has described another embodiment of the invention, and the thermal exchange wherein Beckmann rearrangement district being produced is in the reboiler of distillation tower.Fig. 4 has described one embodiment of the invention, wherein by the reboiler of first distillation tower in thermal exchange to a two series connection distillation tower of Beckmann rearrangement district generation.
Fig. 1
Fig. 1 has described a kind of continuation method and relevant purification step of preparing ε-caprolactam.Pimelinketone enters into cyclohexanone-oxime by line [1] and forms district [A].Add cyclohexanone-oxime forming agent by line [0].The reaction mixture that contains cyclohexanone-oxime producing is input to cyclohexanone-oxime purification section [B] (may also contain cleaning step and/or one or more distilation steps) by line [2].The cyclohexanone-oxime of purifying enters into Beckmann rearrangement district [C] (being made up of one or more continuous levels) by line [3] and adds by line [4] SO that is dissolved in sulfuric acid simultaneously
3(also referred to as oleum).The Beckmann rearrangement mixture obtaining enters into neutral zone [D] while ammoniacal liquor by line [5] and also joins neutral zone by line [6].
The moisture neutralise mixt obtaining enters into phase separation region [E] by line [7], contain aqueous ammonium sulfate leave phase separation region by line [8] mutually and contain moisture crude epsi-caprolactam enter into extraction section [F] by line [9] mutually.The phase of adding organic solvent (being preferably benzene or toluene) and containing moisture crude epsi-caprolactam with its extraction by line [10] in extraction section [F].Contain leaving simultaneously, by line [12], the ε-caprolactam solution that is dissolved in organic solvent is input to distillation zone [G] by line [11] mutually of aqueous ammonium sulfate.By line [13], to distillation zone, [G] adds water, and the streamer that is rich in organic solvent flows out moisture ε-caprolactam streamer simultaneously and flows into final purification section [H] by line [15] from distillation zone by line [14].Final purification section [H] may comprise step of hydrogenation, alkali cleaning step, one or more drying step and/or one or more the finished product distilation steps.Producing the ε-caprolactam of nylon-6 grade discharges by line [16].
Dotted line [17] has been described the hot-fluid leaving from Beckmann rearrangement district [C].This is conventionally by adding water coolant to be achieved to the one or more heat exchangers that are arranged in Beckmann rearrangement district.Dotted line [18] has been described the heat that enters distillation zone [G].This is conventionally by adding steam to be achieved in the reboiler to distillation zone [G].
Fig. 2
Fig. 2 has described one embodiment of the invention.It is identical with equipment described in Fig. 1 substantially.But as described in dotted line [19], the heat that flow out in Beckmann rearrangement district at least partly enters distillation zone [G].This can be achieved (not shown) by one or more heat exchangers.
Fig. 3
Fig. 3 has described one embodiment of the invention.The first step in Beckmann rearrangement district contains mixing equipment [K], collection container [L], pump [M] and in-process heat exchanger [N].The first mixture containing ε-caprolactam keeps circulation by line [101].Add respectively cyclohexanone-oxime and oleum (sulfuric acid and SO by line [102] and [103]
3).By in in-process heat exchanger [N] containing the thermal exchange of the mixture of ε-caprolactam to entering heat exchanger by line [209], then containing in the mixture of ε-caprolactam, organic solvent and water by line [210] discharge.Contain the first mixture of ε-caprolactam and be entered into the mixing equipment of the second stage in Beckmann rearrangement district from collection container [L] recovery part by line [104].
To join line [208] containing the mixture of ε-caprolactam and organic solvent by line [201].The mixture of ε-caprolactam, organic solvent and the water producing is input in in-process heat exchanger [N] by line [209].Can obtain the mixture containing ε-caprolactam and organic solvent with extracting crude epsi-caprolactam in organic solvent, the preferred benzene of organic solvent or toluene, described crude epsi-caprolactam is that cyclohexanone-oxime and oleum carry out Beckmann rearrangement and use in aqueous ammonia and produce.Add the mixture of ε-caprolactam, water and organic solvent to distillation tower [P] by line [210].
Distillation tower [P] may comprise column plate or filler or their combination.Overhead vapours flow in condenser/separator [Q] by line [202], thereby forms the mixture of liquid aqueous phase and liquid organic phase, and discharges by line [203].A kind of tower top that joins distillation tower [P] containing water as phegma by line [204].Optionally, add to line [204] that lambda line [203] flows out containing water using as partial reflux liquid (Fig. 3 does not show).
Discharge the mixture containing ε-caprolactam and water by line [205] from distillation tower [P].Containing the weight fraction of water in the mixture of ε-caprolactam and water be from 2.5wt.% within the scope of 25wt.%.In line [205], can ignore containing the amount of organic solvent in the mixture of ε-caprolactam and water.
By the thermal exchange of the mixture that contains ε-caprolactam and water in in-process heat exchanger [N] is heated to distillation tower [P] containing in the mixture of ε-caprolactam, organic solvent and water in line [209]; This mixture leaves in-process heat exchanger [N] by line [210] mixture.
Optionally, distillation tower [P] optional equipment has all bootable reboilers [R] of any thermal source.In situation, contain the mixture of ε-caprolactam and water to reboiler [R] importation by line [206] like this; And leave reboiler [R] by line [207] and enter distillation tower [P].
Fig. 4
Fig. 4 has described the embodiment that contains two distillation towers in the present invention.Beckmann rearrangement district is substantially with identical described in Fig. 3.But, heat is exchanged to and can be entered in heat exchanger and be entered by line [310] in the mixture containing ε-caprolactam and organic solvent of distillation tower [S] by line [309] containing the mixture of ε-caprolactam from in-process heat exchanger [N].
By line [301], the mixture that contains ε-caprolactam and organic solvent is joined to line [308].The mixture containing ε-caprolactam and organic solvent producing enters in in-process heat exchanger [N] by line [309].Can obtain the mixture containing ε-caprolactam and organic solvent with extracting crude epsi-caprolactam in organic solvent, the preferred benzene of organic solvent or toluene, described crude epsi-caprolactam is that cyclohexanone-oxime and oleum carry out Beckmann rearrangement and use in aqueous ammonia and produce.
Distillation tower [S] may comprise column plate or filler or their combination.Overhead vapours flow in condenser/separator [T] by line [302], thereby forms condensation product, and discharges by line [303].Join the tower top of distillation tower [S] using a kind of organic phase as phegma by line [304].Optionally, add the condensation product of partial line [303] outflow as phegma (Fig. 4 does not show) to line [304].By heat is exchanged to by line [309] heat exchanger [N] and added containing the mixture of ε-caprolactam from in-process heat exchanger [N], leave by line [310] in the mixture containing ε-caprolactam and organic solvent of in-process heat exchanger [N] and heat distillation tower [S].
Optionally, distillation tower [S] optional equipment has all bootable reboilers [U] of any thermal source.Contain the part mixture of ε-caprolactam and organic solvent to reboiler [U] input by line [306]; Enter distillation tower [S] by line [307].The mixture that contains ε-caprolactam and organic solvent by line [305] leaves distillation tower [S] and enters distillation tower [P].
Distillation tower [P] may comprise column plate or filler or their combination.Overhead vapours flow in condenser/separator [Q] by line [202], thereby forms the mixture of liquid aqueous phase and liquid organic phase, and discharges by line [203].A kind of tower top that joins distillation tower [P] containing water as phegma by line [204].Optionally, to line [204] add lambda line [203] flow out containing water as partial reflux liquid (Fig. 4 does not show).
Discharge the mixture containing ε-caprolactam and water by line [205] from distillation tower [P].Containing the weight fraction of water in the mixture of ε-caprolactam and water be from 2.5wt.% within the scope of 25wt.%.In line [205], can ignore containing the amount of organic solvent in the mixture of ε-caprolactam and water.
The reboiler [R] that distillation tower [P] optional equipment has any thermal source all may start.Contain the part mixture of ε-caprolactam and water to reboiler [R] input by line [206]; And leave reboiler [R] by line [207] and enter distillation tower [P].
Embodiment
The present invention further illustrates by following embodiment, but is not limited to this.
In the ε-caprolactam equipment of operate continuously, carry out embodiment and comparative example.For comparative example and contrast convenience according to an embodiment of the invention, will there is the ε-caprolactam equipment of identical throughput as model evaluation embodiment and the comparative example's of embodiment data.
Embodiment 1
Equipment described in employing Fig. 4.The heat that the first step in Beckmann rearrangement district is produced is as separate the energy containing the mixture of ε-caprolactam and benzene in two-step distillating method.
To three-level, Beckmann rearrangement district adds cyclohexanone-oxime.Input 19ton/hr cyclohexanone-oxime by line [102] to first step mixture equipment [K].Input 25ton/hr oleum (sulfuric acid and SO by line [103] to circular route [101]
3).The heat of removing from the mixture containing ε-caprolactam in in-process heat exchanger [N] is approximately 13MW.The temperature containing the mixture of ε-caprolactam that enters in-process heat exchanger [N] is that 96 DEG C and the temperature of leaving the mixture containing ε-caprolactam of in-process heat exchanger [N] are 75 DEG C.
Leave the mixture containing ε-caprolactam of the third stage in Beckmann rearrangement district with aqueous ammonia neutralization, thereby obtained two-phase system (the aqeous ε-caprolactam phase of aqueous ammonium sulfate) (Fig. 4 does not show).In counter-current extraction tower, extract moisture ε-caprolactam phase with benzene, produce the benzol mixture (Fig. 4 not show) of 148ton/hr containing 18.3wt.% ε-caprolactam.In the distillation column equipment of two series connection in a continuous manner from benzene mutually reclaim ε-caprolactam.Two distillation towers all comprise filler.
In the first distillation tower [S], mainly remove benzene at tower top.The tower top temperature of the first distillation tower [S] is that 54 DEG C and tower top pressure are 45kPa.By line [304], 15ton/hr benzene is joined to tower top as phegma.The overhead vapours of the first distillation tower [S] leaves and flow in condenser [T] by line [302], uses there cooling water condensation.The condensation product obtaining leaves by line [303].As tower bottom flow note, flow into second column [P] containing the mixture of ε-caprolactam and benzene by line [305].The flow velocity that contains this mixture of ε-caprolactam and organic solvent is that the weight fraction of 34ton/hr and benzene is 80wt.%.
In second column [P], mainly remove benzene and water at tower top.The tower top temperature of second column and tower top pressure are respectively 75 DEG C and 70kPa.By line [204], 3.2ton/hr water is joined to tower top as phegma.The overhead vapours of second column [P] leaves and flow in condenser [Q] by line [202], uses there cooling water condensation, and the condensation product of acquisition leaves by line [203].The column bottom temperature of second column [P] is 137 DEG C.Mixture containing ε-caprolactam and water leaves by line [205] with flow velocity 28.5ton/hr as tower bottom flow note.Weight fraction containing water in this mixture of ε-caprolactam and water is 5wt.%.Weight fraction containing benzene in this mixture of ε-caprolactam and water can be ignored.By removing and obtain ε-caprolactam (Fig. 4 does not show) water as the overhead product distilling from this mixture containing ε-caprolactam and water.
Two distillation towers are all equipped with the reboiler of activated vapor.In the first distillation tower [U], the steam consumption of reboiler is 4.0MW.In second column [R], the steam consumption of reboiler is 3.3MW.Because having inputted extra heat to the first distillation tower, between the first distillation tower [S] and in-process heat exchanger [N], circulate containing the mixture of ε-caprolactam and benzene by line [308] and [309] 2500ton/hr, get back to the first distillation tower by line [310] afterwards.In in-process heat exchanger [N], 62 DEG C, the mixture containing ε-caprolactam and benzene is heated to 73.5 DEG C.
By line [301] by the charging of two-step distillating method, 148ton/hr is containing the benzol mixture of 18.3wt.% ε-caprolactam, join in the mixture containing ε-caprolactam and benzene in line [308], in described line [308], mixture is to join in the in-process heat exchanger [N] of first recycle system in three-level Beckmann rearrangement district by line [309].
In the first step in Beckmann rearrangement district not to water coolant heat-shift.
Comparative example 1
Except the in-process heat exchangers of heat exchanger [N] right and wrong [N] of the first step in Beckmann rearrangement district but adopt the indirect heat exchanger of water coolant as refrigerant, and outside not being connected with distillation tower, adopt the first step and the distillation zone in the Beckmann rearrangement district similar to embodiment 1.Therefore, can not occur to circulate between the first distillation tower and heat exchanger [N] containing the mixture of ε-caprolactam and benzene.By the charging of two-step distillating method, 148ton/hr, containing the benzol mixture of 18.3wt.% ε-caprolactam, directly joins the first distillation tower (Fig. 4 does not show).
Under above-mentioned condition, in the first distillation tower, the steam consumption of reboiler is 17MW; In second column, the steam consumption of reboiler is 3.3MW.The heat that exchanges to the water coolant in first step heat exchanger in three-level Beckmann rearrangement district is 13MW.
Embodiment 1 is clear have been shown compared with the method with prior art described in comparative example 1, the heat that adopts the first step in Beckmann rearrangement district to produce in the first distillation tower separates the mixture containing ε-caprolactam and benzene as thermal source, and steam consumption has further reduced 13MW.In addition, show compared with the method with prior art described in comparative example 1, by introduce this mode of in-process heat exchange, the heat of transferring to the water of condensation in first step water cooler in three-level Beckmann rearrangement district has lowered 13MW.Therefore the method for embodiment 1 is carried out the first step for Beckmann rearrangement district without water coolant.
Equipment described in employing Fig. 3, wherein only have not same, not by the charging of distillation tower, 148ton/hr is containing the benzol mixture of 18.3wt.% ε-caprolactam, joins line [208] but the tower top from distillation tower [P] joins theoretical tray 4 (Fig. 3 does not show) by it.The heat that the first step in Beckmann rearrangement district is produced is as separate the energy containing the mixture of ε-caprolactam and benzene in one-step distillating method.
To three-level, Beckmann rearrangement district adds cyclohexanone-oxime.By line [102] phase first step mixing equipment [K] input 19ton/hr cyclohexanone-oxime.Input 25ton/hr oleum (sulfuric acid and SO by line [103] to circular route [101]
3).The heat of removing from the mixture containing ε-caprolactam in in-process heat exchanger [N] is approximately 13MW.The temperature containing the mixture of ε-caprolactam that enters in-process heat exchanger [N] is that 96 DEG C and the temperature of leaving the mixture containing ε-caprolactam of in-process heat exchanger [N] are 75 DEG C.
Leave the mixture containing ε-caprolactam of the third stage with aqueous ammonia neutralization, thereby obtained two-phase system (the aqeous ε-caprolactam phase of aqueous ammonium sulfate) (Fig. 3 does not show).In counter-current extraction tower, extract moisture ε-caprolactam phase with benzene, produce the benzol mixture (Fig. 3 not show) of 148ton/hr containing 18.3wt.% ε-caprolactam.In distillation tower [P] in a continuous manner from benzene mutually reclaim ε-caprolactam.Distillation tower [P] all comprises having 20 theoretical trays.
In distillation tower [P], mainly remove benzene and water at tower top.The tower top temperature of distillation tower [P] and tower top pressure are respectively 58 DEG C for 60kPa.Join the tower top of distillation tower [P] using 11.6ton/hr water as phegma by line [204].The overhead vapours of distillation tower [P] leaves and flow in condenser [Q] by line [202], uses there cooling water condensation, and the condensation product of acquisition leaves by line [203].The column bottom temperature of distillation tower [P] is 136 DEG C.Mixture containing ε-caprolactam and water leaves by line [205] with flow velocity 29.3t/hr as tower bottom flow note.Weight fraction containing water in this mixture of ε-caprolactam and water is 8wt.%.Amount containing benzene in this mixture of ε-caprolactam and water can be ignored.By water distillation from this mixture containing ε-caprolactam and water is removed and is obtained ε-caprolactam (Fig. 3 does not show).
Distillation tower [P] is equipped with the reboiler [R] of activated vapor.In distillation tower [P], the steam consumption of reboiler [R] is 11MW.Because having inputted extra heat to distillation tower [P], by the circulation between the theoretical tray 8 of distillation tower [P] and in-process heat exchanger [N] of the mixture containing ε-caprolactam and benzene, get back to distillation tower [P] by line [210] by line [208] and [209] afterwards.In in-process heat exchanger [N], 62 DEG C, the mixture containing ε-caprolactam and benzene is heated to 73.5 DEG C, thereby has absorbed 13MW heat.
In the first step in Beckmann rearrangement district not to water coolant heat-shift.
Comparative example 2
Except the in-process heat exchanger of heat exchanger [N] right and wrong of the first step in Beckmann rearrangement district but adopt the indirect heat exchanger of water coolant as refrigerant, and outside not being connected with distillation tower, adopt the first step and the distillation zone in the Beckmann rearrangement district similar to embodiment 2.Therefore, can not occur to circulate between distillation tower and heat exchanger [N] containing the mixture of ε-caprolactam and benzene.By the charging of two-step distillating method, 148ton/hr, containing the mixture of the benzene of 18.3wt.% ε-caprolactam, directly joins theoretical tray 4 (Fig. 3 does not show) from distillation tower tower top.
Under above-mentioned condition, in distillation tower, the steam consumption of reboiler is 24MW.The heat that exchanges to the water coolant in first step heat exchanger in three-level Beckmann rearrangement district is 13MW.
Claims (16)
1. a method of producing continuously ε-caprolactam, the method contains in order,
A) by i) oleum and/or sulfuric acid and ii) cyclohexanone-oxime is input to Beckmann rearrangement district;
B) mixture containing ε-caprolactam producing is discharged from Beckmann rearrangement district;
C) ammonia is joined to the mixture containing ε-caprolactam;
D) from isolating ammonium sulfate containing the mixture of ε-caprolactam;
E) in organic solvent from containing the mixture extraction ε-caprolactam of ε-caprolactam;
F) add water conservancy distillation and from the ε-caprolactam of extraction, remove organic solvent in distillation zone;
Be characterised in that the reaction heat that at least part of Beckmann rearrangement district is produced exchanges to distillation zone.
2. method according to claim 1, wherein adopts intermediate heat transfer that heat is exchanged to distillation zone from Beckmann rearrangement district.
3. method according to claim 1, does not wherein adopt intermediate heat transfer that heat is exchanged to distillation zone from Beckmann rearrangement district.
4. method according to claim 3, what wherein step a) is produced passes through the second Room of this heat exchanger containing the mixture of ε-caprolactam by the ε-caprolactam in the first Room of in-process heat exchanger and the organic solvent that will distill in f) in step.
5. according to the method described in any one of claim 1 to 4, wherein distillation zone contain at least one with organic solvent as the distillation tower of phegma and at least one water the distillation tower as phegma.
6. method according to claim 5, the reaction heat that wherein at least part of Beckmann rearrangement district produces is switched in the distillation tower of organic solvent as phegma.
7. according to the method described in any one of claim 1 to 6, the reaction heat that wherein at least part of Beckmann rearrangement district produces is switched in the reboiler of organic solvent as the distillation tower of phegma
8. according to the method described in any one of claim 1 to 7, wherein organic solvent is benzene or toluene.
9. according to the method described in any one of claim 1 to 8, wherein exchange to before distillation zone at the reaction heat that at least part of Beckmann rearrangement district is produced, the mixture containing ε-caprolactam leaving from Beckmann rearrangement district has the temperature of 75 DEG C to 140 DEG C.
10. according to the method described in any one of claim 1 to 9, wherein adopting organic solvent is that the distillation tower column bottom temperature of phegma is 50 DEG C to 130 DEG C.
11. according to the method described in any one of claim 1 to 10, and wherein adopting organic solvent is that the distillation tower tower top pressure of phegma is that 20kPa is to 100kPa.
12. according to the method described in any one of claim 1 to 11, and wherein Beckmann rearrangement district has a higher level and Beckmann rearrangement district produces at least partly reaction heat is to produce in the first step.
13. according to the method described in any one of claim 1 to 12, and wherein said method also contains to be utilized in hydroxylamine sulfate buffering system pimelinketone and azanol reaction or utilizes ammoxidation of cyclohexanone to prepare and join the cyclohexanone-oxime in Beckmann rearrangement district.
14. according to the method described in any one of claim 1 to 13, and wherein said method also contains the ε-caprolactam that further distillation zone f) produces from step removes water.
15. 1 kinds are applicable to carrying out the equipment of method as described in any one of claim 1 to 14, and this equipment contains Beckmann rearrangement district and distillation zone; Be characterised in that described equipment contains one or more heat exchangers that are designed to heat to be exchanged to from Beckmann rearrangement district distillation zone.
16. ε-caprolactam that obtain according to method described in any one of claim 1 to 14.
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| CN105061311A (en) * | 2015-08-13 | 2015-11-18 | 江苏三鼎石化科技有限公司 | Caprolactam refining technology |
| CN105315211A (en) * | 2014-08-01 | 2016-02-10 | 中国石油化工股份有限公司 | Method for preparing caprolactam through catalyzing cyclohexanone oxime by high-concentration fuming sulfuric acid |
| CN107311929A (en) * | 2016-04-27 | 2017-11-03 | 中国石油化工股份有限公司 | A kind of preparation method of caprolactam |
| CN108341763A (en) * | 2018-04-24 | 2018-07-31 | 河北美邦工程科技股份有限公司 | A kind of caprolactam crystallization purifications |
| WO2021094184A1 (en) | 2019-11-11 | 2021-05-20 | Cap Iii B.V. | PROCESS AND PLANT FOR THE PRODUCTION OF ε-CAPROLACTAM AND AMMONIUM SULFATE ON INDUSTRIAL SCALE |
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| CN105315211A (en) * | 2014-08-01 | 2016-02-10 | 中国石油化工股份有限公司 | Method for preparing caprolactam through catalyzing cyclohexanone oxime by high-concentration fuming sulfuric acid |
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| WO2021094184A1 (en) | 2019-11-11 | 2021-05-20 | Cap Iii B.V. | PROCESS AND PLANT FOR THE PRODUCTION OF ε-CAPROLACTAM AND AMMONIUM SULFATE ON INDUSTRIAL SCALE |
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