CN104710317B

CN104710317B - With the nylon salt solution production method for the container production PBA solution for having dispersing head

Info

Publication number: CN104710317B
Application number: CN201410143832.9A
Authority: CN
Inventors: 罗伯特·J·韦尔奇
Original assignee: Invista Textiles UK Ltd
Current assignee: Invista Textiles UK Ltd
Priority date: 2013-12-17
Filing date: 2014-04-10
Publication date: 2019-01-25
Anticipated expiration: 2034-04-10
Also published as: TW201529640A; CN104710317A; WO2015094394A1

Abstract

It is a kind of for producing the continuation method of nylon salt solution, the nylon salt solution is to be prepared using the partial equilibrium acid solution rich in dicarboxylic acids, especially adipic acid.By weight, liquid feedstock is prepared by measuring the dicarboxylic acid powder from loss in weight feeder to feed pipe, dicarboxylic acid powder is delivered to the container including dispersing head by the feed pipe；First feed stream material of diamines is formed into the dispersion comprising the water between the diamines and 39 weight % and 57 weight % between dicarboxylic acids, 11 weight % and the 15 weight % between 32 weight % and 46 weight % into container；And partial equilibrium acid solution is formed in 50 DEG C and 60 DEG C of at a temperature of heating dispersion.Nylon salt solution is prepared from partial equilibrium acid solution, and is continuously withdrawn from into storage tank.The nylon salt solution has uniform pH value, and suitable for production nylon polymer.

Description

With the nylon salt solution production method for the container production PBA solution for having dispersing head

The cross reference of association request

This application claims the priority for enjoying in the U. S. application 61/917,022 that on December 17th, 2013 submits, the Shens It full content please and discloses incorporated herein.

Technical field

The present invention relates to the preparations of nylon salt solution, and in particular to it is molten to balance acid using the liquid portion rich in dicarboxylic acids Liquid, and nylon salt solution is prepared using including the disperser of the container with dispersing head.

Background technique

Polyamide commonly used in textile, clothes, packaging, tire enhancing, woollen blanket, for automobile profiled part engineering Thermoplastic, electrical equipment, athletic equipment and extensive industrial application.Nylon is a kind of high performance material, be can be used for It is required that in the plastics and fiber applications of superpower durability, heat resistance and toughness.Referred to as the fatty polyamide of nylon can be from two The salting liquid of carboxylic acid and diamines produces to obtain.The salting liquid is evaporated, is then heated to cause polymerization.This production work A challenge in skill is guaranteed in final polyamide, and dicarboxylic acids is consistent with the mol balance of diamines.For example, when from oneself two Sour (adipic acid, AA) and hexamethylene diamine (hexamethylene diamine, HMD) are inconsistent come when producing nylon 6,6 Mol balance can adversely reduce molecular weight and may will affect the dyeability of nylon.It is realized mole using batch salt method flat Weighing apparatus, but batch method is not suitable for large scale industry production.In addition, being realized in a continuous mode mole by multiple reactors flat Weighing apparatus, during salt production, each reactor has independent diamines feeding device.

U.S. Patent Publication 2010/0168375 teaches the salting liquid for preparing diamines and diacid, more specifically, teaching It is prepared for a kind of concentrated solution of adipic acid hexamethylenediamine salt, is the useful starting material for producing polyamide, more specifically, It is the useful starting material for producing PA66.The salting liquid is made by mixing diacid and diacid, and the quality of salt is dense Degree is 50% to 80%, in the first step, provides the aqueous solution of the diacid and diamines with diacid/diamine molar ratio greater than 1.1, And in the second step, diacid/diamine molar ratio is adjusted to the value of 0.9-1.1, preferably 0.99-1.01 by addition diamines Value, and by the way that optionally addition water corrects the mass concentration of the salt thereto.Similarly, U.S. Patent Publication 2012/0046439 teaches and prepares salting liquid through multiple steps with two different diacid.

United States Patent (USP) 4442260 teaches a kind of method for manufacturing the nylon salt solution of high concentration, wherein diamines with Two parts are added, and water is being added a part before the step of evaporation in the solution of maxima solubility, and another part is being incited somebody to action Water is added after the step of evaporation in the solution of maxima solubility.

United States Patent (USP) 4213884 is taught by the way that the alkyl dicarboxylic aid of 6-12 carbon atom and diamine reactant are manufactured two The method of the high concentration solution and nylon precondensate of the salt of carboxylic acid and diamines.It will contain and dissolve excessive special two in right amount The aqueous solution of the salt of the dicarboxylic acids and diamines of the low concentration of carboxylic acid is reacted with the special diamines under molten state, the spy Diamines is identical as the amount of the dicarboxylic acids of dissolution under different molten state, and the reaction carries out under conditions of super-atmospheric pressure, and will End reaction temperature is maintained between 140 DEG C to 210 DEG C.It is used for obtained solution to manufacture nylon.

United States Patent (USP) 4131712 teaches a kind of method for manufacturing superpolyamide, wherein with non-stoichiometric It is preferably low under the fusion temperature lower than polyamide product to prepare component rich in diacid respectively and rich in the component of diamines In 200 DEG C, each of these components are melted；Then by the component rich in diacid and it is rich at sufficiently high temperature The component of diamines is contacted with liquid condition, to prevent from solidifying, and is contacted in a proportional manner so that diacid and The total amount of diamines is stoichiometry as far as possible, whether is it in conjunction with.

As the other methods of United States Patent (USP) 5801278 and 5674974, WO99/61510 and EP0411790 are sought to manufacture nothing Water nylon salt solution.It has been observed that complicated and time-consuming method may be decreased throughput rate and to limit it molten in nylon salt Application in the industrial production of liquid.For example, United States Patent (USP) 6995233 describe it is a kind of for manufacturing the continuation method of polyamide. The polyamide is obtained from diacid and diamines.The method includes continuously mixing rich in amine-terminated compound and rich in acid The operation of the compound of end group, and operated using the polycondensation of the mixture.This method is related to the initial phase of this technique, During the initial phase, the aqueous solution containing essence at the mixture of the monomer of stoichiometric ratio is used.Constitute the described of precursor Mixture can be anhydrous or containing the up to water of 10 mass %.

Although being made that effort in terms of improving technique to realize goal standard, such as the suitable pH in nylon salt solution In terms of value, mol balance and/or salinity, but still there is challenge.Especially dicarboxylic acids (more specifically adipic acid) is a kind of Powder with variable particle size, this leads to the big variation of bulk density and the flow behavior of difference.Drawn using dicarboxylic acid powder Enter another variable, makes the homogeneity for being difficult to realize goal standard in a continuous process.Body for dicarboxylic acid powder Product feeder is exaggerated this difficulty.

Therefore it needs to improve to control the homogeneity of the nylon salt using dicarboxylic acid powder.

Summary of the invention

In first embodiment, the present invention relates to production nylon salt solution continuation method, including formed for The partial equilibrium acid solution stored at a temperature of between 50 DEG C and 60 DEG C with liquid condition, comprising the following steps: by weight, lead to Cross the charging for measuring the dicarboxylic acid powder from loss in weight feeder to feed pipe to control dicarboxylic acids (preferably adipic acid) powder Rate change rate, dicarboxylic acid powder is delivered to the container including dispersing head by the feed pipe, and the first of diamines is fed Logistics is fed into container to be formed comprising between dicarboxylic acids, 11 weight % and the 15 weight % between 32 weight % and 46 weight % The dispersion of water between diamines and 39 weight % and 57 weight %.On the one hand, the partial equilibrium acid solution not will form silt Slurry.Furthermore it is preferred that nylon salt solution not introduced to container to form dispersion.The method further includes from partial equilibrium Acid solution forms the nylon salt solution for realizing target salinity and target ph, comprising the following steps: from the dispersion of storage Withdraw from a part of partial equilibrium acid solution, and by second feed stream one of a part of the partial equilibrium acid solution and diamines It rises to be introduced into single stirred tank reactor and forms nylon salt solution, then connect nylon salt solution from single stirred tank reactor It is continuous to withdraw from, and be directly entered in storage tank, wherein the salinity relative target salinity of nylon salt solution is being less than ± 0.5% model Interior variation is enclosed, and the pH value relative target pH value of nylon salt solution changes in the range of being less than ± 0.04.Target pH can be choosing Value between 7.200 and 7.900, the value between preferably 7.400 and 7.700.Target salinity can be for selected from 50 Value between value between weight % and 65 weight %, preferably 60 weight % and 65 weight %.On the one hand, dicarboxylic acids powder The feed-rate variation rate that end is fed to container is less than ± 5%, preferably smaller than ± 3%.The container can further comprise having one The recirculation circuit of a or multiple direct insertion mixers.The method is related to feeding at least two strands of diamines streams, one is fed into appearance Device and another stock is fed into continuous stirred tank reactor.In one embodiment, the first feed stream of diamines includes 15 weights The water of the diamines and 70 weight to 85 weight % between % and 30 weight % is measured, and the second feed stream of diamines includes 20 weight % And the water of 100 diamines and 0 weight % to 80 weight % between weight %.First feed stream of more preferable diamines includes 20 weights The water of the diamines and 70 weight to 80 weight % between % and 30 weight % is measured, and the second feed stream of diamines includes 65 weight % And the water of 100 diamines and 0 weight % to 35 weight % between weight %.

The present invention may also include the process control for producing nylon salt solution.In one embodiment, pass through production Model set the feed rate of the first feed stream of diamines and the second feed stream of diamines, including setting nylon salt is molten The throughput rate of liquid sets the feed rate of dicarboxylic acid powder to realize the throughput rate, and sets nylon salt solution Target ph.In addition, the model can determine compensation diamines.The model, which can also be used to determine, is fed into container and reactor The feed rate of water.The process control can further comprise by adding in the upstream of one or more pumps and analyzer circuit Diamines feed stream is compensated to adjust the pH value of nylon salt solution, and the pH value of the nylon salt solution in analyzer circuit. Due to the condition of variation, on-line pH value measurement data may differ from target ph, and can make when there are the variation of pH value Adjustment.On the one hand, sample can be removed from analyzer circuit to carry out offline pH value measurement.In order to improve sensitivity, can pass through The content in analyzer circuit is diluted to the concentration between 8% and 12%, and the content in analyzer circuit is cooled to 15 DEG C and 40 DEG C between temperature carry out online or offline pH value measurement.

In the second embodiment, the present invention relates to the continuous processings for producing nylon salt solution, including are formed and used In the partial equilibrium acid solution stored at a temperature of between 50 DEG C and 60 DEG C with liquid condition, comprising the following steps: with weight Meter controls the feed-rate variation of dicarboxylic acid powder by measuring the dicarboxylic acid powder from loss in weight feeder to feed pipe Dicarboxylic acid powder is delivered to the container including dispersing head by rate, the feed pipe, and by the first feed streams of diamines Formed into container comprising between dicarboxylic acids, 11 weight % and 15 weight % between 32 weight % and 46 weight % diamines and The dispersion of water between 39 weight % and 57 weight %.On the one hand, the partial equilibrium acid solution not will form slurry.In addition, It is preferred that nylon salt solution not introduced to container to form dispersion.The method further includes from partial equilibrium acid solution shape At the nylon salt solution for realizing target ph, comprising the following steps: withdraw from partial equilibrium acid solution from the dispersion of storage A part, and the second feed stream of a part of the partial equilibrium acid solution and diamines is concomitantly introduced into single continuous stirred tank Nylon salt solution is formed in reactor, then continuously withdraws from nylon salt solution from single continuous stirred tank reactor, and It is directly entered in storage tank.Nylon salt solution has the pH value phase of the salinity and nylon salt solution between 50 weight % and 65 weight % Target ph is changed in the range of within ± 0.04.Target ph can be between 7.200 and 7.900 Value, the value between preferably 7.400 and 7.700.

In third embodiment, the present invention relates to the process units for producing nylon salt solution comprising weightless Formula feeder, the loss in weight feeder include hopper, feed pipe and the conduit for connecting hopper and feed pipe, wherein The hopper include for control supplemental stages and charging stage at least one external weights measure subsystem, and for into The material stage distributes at least one lower openings of dicarboxylic acid powder, wherein at least one described lower openings are placed in feed pipe Top, and wherein feed pipe receives dicarboxylic acid powder, and is exported by least one rotation spiral to convey dicarboxylic acids powder End.The process unit further comprises: container, and the container includes one or more dispersing heads, the first recirculation circuit, connects Be connected to the first import of the outlet of feed pipe and the first feed stream for introducing diamines with formed the second of dispersion into Mouthful；Wherein the first recirculation circuit includes direct insertion mixer and fluid level control valve；For the temperature between 50 DEG C and 60 DEG C The storage tank of lower storage dispersion is come from wherein the storage tank includes the second recirculation circuit for connecting fluid level control valve with receiving The dispersion of container；And continuous stirred tank reactor, be used to receive the dispersion of storage a part and diamines second Feed stream, to produce nylon salt solution.

In the 4th embodiment, the present invention relates to the methods polymerizeing for nylon salt solution, including by adipic acid and Hexamethylene diamine formation nylon 6,6, including nylon salt solution is evaporated to form concentration stream, and polymerize the concentration in the second reactor Stream forms polyamide product.As described herein, nylon salt solution is prepared from PBA solution.In one embodiment, it can incite somebody to action A part of partial equilibrium acid solution introduces polymer reactor.

Detailed description of the invention

The present invention is more fully understood below in conjunction with unrestricted attached drawing, in which:

Fig. 1 is according to an embodiment of the invention for producing the overview flow chart of nylon salt solution.

Fig. 2 is according to an embodiment of the invention for producing the loss in weight feeder of the PBA solution rich in AA With the schematic diagram with the container with dispersing head.

Fig. 3 is the schematic diagram according to the continuous stirred tank reactor of an embodiment of the invention.

Fig. 4 is the schematic diagram according to the process control of an embodiment of the invention.

Fig. 5 is the schematic diagram according to the nylon 6,6 production technology of an embodiment of the invention.

Fig. 6-8 is the display according to an embodiment of the invention from the charging of the adipic acid of loss in weight feeder speed The chart of rate variation.

Specific embodiment

Term used herein is not intended to limit the present invention merely for the purpose of description specific embodiment.On unless Hereinafter clearly show other situation, singular as used herein "one" and "the" also include plural form. It is also understood that illustrating that there are the features, whole when the term " comprising " used in the present specification and/or " including " Body, step, operation, component and/or component, but do not interfere other one or more features, entirety, step, operation, component group, The presence or addition of component and/or component groups.

Such as "include", "comprise", " having ", " containing " or " being related to " term and its variant should widely understand, and And include listed main body and equivalent, there are also unlisted other main bodys.In addition, when by transitional phrases " packet Containing ", " comprising " or " containing " when drawing component, component group, technique or method and step or any other statement, should manage Solution it is contemplated herein that identical component, component group, technique or method and step, or have the component, component group, technique or Transitional phrases "consisting essentially of ...", " Consists of " or " choosing before the record of method and step or any other statement Any other statement of freely ... the group of composition ".

If applicable, the device or step of corresponding structure, material, movement and all functionalities in claim Rapid equivalent includes any knot for executing function in combination with the other component specifically stated in claim Structure, material or movement.Specification of the invention for introduce and description purpose and provide, but be not exhaustive or will this Invention is restricted to disclosed form.Under the premise of without departing from scope and spirit of the present invention, it is many change and variant for It is obvious for those skilled in the art.Here some embodiments have been chosen and described, it is therefore an objective to this The principle and practical application of invention carries out optimal explanation, and makes others of ordinary skill in the art it will be appreciated that originally The different embodiments of invention have a variety of variations, as being suitable for the special-purpose.Correspondingly, although the present invention It is described according to embodiment, however it would be recognized by those skilled in the art that the present invention can change ground and in institute Implement within attached spirit and scope of the claims.

Now with detailed reference to specific disclosed theme.Although disclosed theme will be wanted in conjunction with cited right It asks to describe, it being understood, however, that disclosed theme is not restricted in these claims by they.On the contrary, disclosed Theme cover all alternative solutions, change and equivalent, these may include in institute defined by the claims Within the scope of disclosed theme.

Introduction

What is produced the invention mainly relates to the production of nylon salt solution and from the nylon salt solution of dicarboxylic acids and diamines is poly- Amide.Particularly, the liquid part the present invention relates to production rich in dicarboxylic acids balances sour (PBA) solution, also known as rich acid charging, It is as feedstock solution come using to form nylon salt solution.Nylon salt solution is formed to realize target salinity and/or target PH value.PBA solution is partial equilibrium, and can not achieve the target ph or target salinity of nylon salt solution.Individually connecting In continuous stirred tank reactor, PBA solution can be produced in conjunction with the charging of another diamines and water to realize that target has to produce The nylon salt solution of uniform pH value.Advantageously, PBA solution allows to introduce the dicarboxylic acids of liquid phase into single continuous stirred tank reaction In device.In one embodiment, the nylon salt solution with uniform pH value is polymerizable to form nylon 6,6.According to using Initial monomers can produce other kinds of polyamide.

As described below, dicarboxylic acids and diamines are indicated using term adipic acid (AA) and hexamethylene diamine (HMD).When using oneself two When sour, PBA solution is the solution of adipic acid of partial equilibrium.But this method can also be applied to other dicarboxyls noted here Acid and other diamines.

Be suitable for the invention dicarboxylic acids and be selected from the group that is made of following compound: ethanedioic acid, malonic acid, succinic acid, Glutaric acid, pimelic acid, adipic acid, suberic acid, azelaic acid, decanedioic acid, heneicosanedioic acid, dodecanedioic acid, maleic acid, amylene two Acid, traumatic acid, muconic acid, 1,2- cyclohexane dicarboxylic acid or 1,3- cyclohexane dicarboxylic acid, 1,2- phenylenediacetic Acid or 1,3- benzene diethyl Acid, 1,2- cyclohexanediacetic or 1,3- cyclohexanediacetic, M-phthalic acid, terephthalic acid (TPA), 4,4 '-diphenyl ether diformazans Acid, 4,4- benzophenone dicarboxylic acids, 2,6- naphthalene dicarboxylic acids, the p- M-phthalic acid tert-butyl ester and 2,5- furan dicarboxylic acid and it Mixture.In one embodiment, the dicarboxylic acid monomer includes at least 80% adipic acid, for example, at least 95% Adipic acid.

For manufacture nylon 6,6, adipic acid (AA) is most suitable dicarboxylic acids and uses in powder form.AA is usual It can obtain in pure form, contain very low loadings of impurity.Typical impurity includes other sour (monoacid and rudimentary binary Acid), it is less than 60ppm；Nitrogen substance；Trace metal, as iron (be less than 2ppm) and other heavy metals (be lower than 10ppm or less than 5ppm)；Arsenic (is less than 3ppm)；With hydrocarbon-type oil (being less than 10ppm or less than 5ppm).

Be suitable for the invention diamines and be selected from the group that is made of following compound: ethanoldiamine, propane diamine, butanediamine, It is cadaverine, hexamethylene diamine, 2 methyl pentamethylenediamine, heptamethylene diamine, 2- methyl hexamethylene diamine, 3- methyl hexamethylene diamine, 2,2- dimethyl-penten diamines, pungent Diamines, 2,5- dimethylhexanediamine, nonamethylene diamine, 2,2,4- trimethylhexane diamine and 2,4,4- trimethylhexane diamine, decamethylene diamine, 5- Methyl nonamethylene diamine, isophorone diamine, 11 diamines, 12 diamines, 2,2,7,7- tetramethyl octamethylenediamine, two (p- aminocyclohexyls Base) methane, two (amino methyl) norbornanes, the C2-C16 optionally replaced by the alkyl group of one or more C1-C4 rouge Race's diamines, aliphatic polyether diamines and furans diamines, such as (amino methyl) furans of 2,5- bis- and their mixture.It is selected Diamines can have boiling point more higher than dicarboxylic acids, and the diamines is not preferably m-xylene diamine.In an embodiment party In formula, the diamine monomer includes at least 80% hexamethylene diamine, for example, at least 95% hexamethylene diamine.Hexamethylene diamine (HMD) is the most frequently used In preparing nylon 6,6.HMD solidifies at about 40 DEG C to 42 DEG C, and usually plus water becomes easy to reduce this fusing point and to handle. Therefore, HMD can be used as concentrated solution and buy, for example, as from 80 weight % to 100 weight % or from 92 weight % to 98 weights The concentrated solution of amount % is bought.

Other than being based only upon the polyamide of dicarboxylic acids and diamines, it is advantageous in conjunction with other monomers sometimes.When with small In the ratio of 20 weight %, when the ratio of such as less than 15 weight % is added, these monomers can be added in nylon salt solution, without It departs from the scope of the present invention.These monomers may include monofunctional carboxylic acids, such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, benzene first Acid, caproic acid, enanthic acid, octanoic acid, n-nonanoic acid, capric acid, hendecanoic acid, lauric acid, myristic acid, myristoleic acid, palmitinic acid, palm oil Acid, Sa Fen sour (sapienic acid), stearic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, erucic acid etc..These monomers can also Including lactams, such as α-beta-lactam, α-azetidinone, azetidinone, butyrolactam, δ-valerolactam, γ-penta Lactams, caprolactam etc..These monomers may also comprise lactone, such as α-second lactone, α-propiolactone, beta-propiolactone, γ-Ding Nei Ester, δ-valerolactone, gamma-valerolactone, caprolactone etc..These monomers may include difunctional alcohol, such as monoethylene glycol, diethylene glycol (DEG), 1, 2- propylene glycol, 1,3- propylene glycol, dipropylene glycol, 1,2- butanediol, 1,3 butylene glycol, 1,4- butanediol, 2,3- butanediol, 1,2- Pentanediol, 1,5-PD, Rutgers 612 (etohexadiol), p- Meng's alkane -3,8- glycol, 2- methyl -2,4- pentanediol, 1,6- Hexylene glycol, 1,7- heptandiol and 1,8- ethohexadiol.The molecule that more advanced function can also be used, such as glycerol, trimethylolpropane, Triethanolamine etc..Also selected from suitable azanol, such as ethanol amine, diethanol amine, 3- amino -1- propyl alcohol, 1- amino -2- third Alcohol, 4- amino-n-butyl alcohol, 3- amino-n-butyl alcohol, 2- amino-n-butyl alcohol, 4- amino -2- butanol, amylalcohol amine, hexanol amine etc..It answers Understand, it is possible to use the mixture of any of these monomers, without departing from the scope of the present invention.

Other additives are combined into being also advantageous in polymerization technique sometimes.These additives may include heat stabilizer, Such as mantoquita, potassium iodide or any other antioxidants as known in the art.Such additive also may include polymerization catalyzed Agent, such as the metal salt or other compounds of metal oxide, acid compound, phosphine oxide compounds as known in the art. Such additive is also possible to delustering agent and colorant, such as titanium dioxide, carbon black or other pigment as known in the art, Dyes and dyestuffs.Used additive also may include defoaming agent, as silica dispersion, Organosiliconcopolymere or Other defoaming agents as known in the art.Lubricating auxiliary agent can be used, such as zinc stearate, stearyl erucic amide, stearyl alcohol, distearyl Sour aluminium, ethylene bis stearamide or other polymeric lubricants as known in the art.It may include nucleating agent in mixture, such as Fumed silica or aluminium oxide, molybdenum disulfide, talcum, graphite, calcirm-fluoride, phenyl phosphinic acid salt or it is as known in the art its Its auxiliary agent.Also other common additives known in the art are added in the course of the polymerization process, as fire retardant, plasticizer, anti-impact change Property agent and certain form of filler.

Present invention advantageously achieves the nylon salt solutions comprising the AA/HMD salt with target ph.Particularly, with biography System method is compared, and the present invention realizes target ph using small number of container, particularly, is realized in single reactor Target ph, such as the single continuous stirred tank reactor (continuous in the formation that nylon salt solution wherein occurs Stirred tank reactor, CSTR) in.In this application, using the container and single continuous stirred tank for including dispersing head Reactor prepares nylon salt solution, produces compared to batch, can realize higher throughput rate.In batch production, use Make in the time of equipment and the quantity of fund cost for realizing the productivity similar with the achievable productivity of continuous production Batch production is infeasible.Target ph can be any pH value of those skilled in the art's selection, and can be based on the final poly- of needs Composition powder selects.Without being limited by theory, target value can be selected from the highest inflection point slope of pH curve, and in for wanting Polymeric articles the optimal level in region.

In some illustrative embodiments, the target ph of nylon salt solution can model between 7.200 and 7.900 Interior value is enclosed, such as preferably between 7.400 and 7.700.Target of the actual pH of nylon salt solution relative to nylon salt solution The variation of pH value can be less than ± 0.04, more preferably less than ± 0.03, most preferably in less than ± 0.015.Thus, for example if target pH Value is 7.500, then the pH value of nylon salt solution is between 7.460 and 7.540, more preferably between 7.470 and 7.530. For purposes of the present invention, the change rate of pH value refers to the average rate of change of continuous operation.The change rate is very low, less than ± 0.53%, more preferably less than ± 0.4%, and produce the nylon salt solution for having uniform pH value.With relative to the low of target ph The uniform nylon salt solution of change rate is conducive to improve the reliability of polymerization process, to produce the polymer of homogeneous, high-quality Product.Nylon salt solution with uniform pH value also allows for the charging of stabilised quality to be able to enter polymerization process.Target ph It can be changed according to manufacturing location.Under normal circumstances, the pH value of the salinity of measurement 9.5% is 7.620 such as at 25 DEG C, raw The nylon salt solution that the molar ratio with AA ratio HMD is 1 is produced, the molar ratio is based on free and chemical bonding AA and HMD.Out In the purpose of the present invention, according to target ph, the molar ratio can change in the range of 0.8-1.2.With uniform pH value Mean that the molar ratio of nylon salt solution has corresponding low rate of change.

In addition to target ph, the present invention can also be achieved target salinity.The target salinity can be art technology Any salinity of personnel selection, and can be considered based on the final polymeric articles of needs and storage to select.Nylon salt solution Water concentration can be between 35 weight % and 50 weight %.Nylon salt solution can have the salt between 50 weight % and 65 weight % dense Degree, for example, between 60 weight % and 65 weight %.The change rate of the salinity of nylon salt solution is preferably very low, such as relatively It is less than ± 0.5% in target salinity, less than ± 0.3%, less than ± 0.2% or less than ± 0.1%.For purposes of the present invention, salt The change rate of concentration refers to the mean change of continuous operation.Thus, for example, if target salinity is 60%, it is uniform Nylon salinity has the salinity between 59.5 weight % and 60.5 weight %, preferably has in 59.7 weight % and 60.3 weight % Between salinity, more preferably there is salinity between 59.9 weight % and 60.1 weight %.Target salinity can be according to system It makes place and changes.

Nylon salt solution can be used as liquid lower than 110 DEG C temperature and atmospheric pressure under store, such as at 60 DEG C and 110 At a temperature of between DEG C, or at a temperature of between 100 DEG C and 105 DEG C.The temperature more demanding higher than the concentration of 65 weight % is simultaneously It may need to pressurize, to keep nylon salt solution as liquid, such as homogeneous liquid.The salinity can influence storage temperature, and And under normal circumstances, nylon salt solution can be effectively stored in lower temperature and under normal pressure.But it is carrying out polymerizeing it Before, lower salinity can things turn out contrary to one's wishes that ground increases energy consumption so that the nylon salt solution is concentrated.

The temperature of nylon salt solution is not influenced and independently controlled by the molar ratio of AA ratio HMD.Although nylon salt solution In molar ratio and the concentration of solid will affect the temperature of nylon salt solution, but the method dependent on heat exchanger, coil pipe and/ Or the CSTR with collet removes heat from the process, thus controls the temperature of nylon salt solution.Controllable nylon salt is molten The temperature of liquid changes in the range of being less than ± 1 DEG C compared to required temperature.In the boiling point lower than nylon salt solution but it is higher than knot Brilliant temperature selects the temperature of nylon salt solution.For example, the nylon salt solution that solid concentration is 63% has 108 under atmospheric pressure DEG C to 110 DEG C of boiling point.Therefore, temperature is controlled less than 110 DEG C, such as less than 108 DEG C, but is above crystallization temperature.

AA is introduced nylon salt solution using PBA solution by the present invention, and PBA solution will not realize nylon salt solution Target ph or target salinity.It is preferred that the full dose of AA needed for nylon salt solution is introduced PBA solution, to realize AA concentration Low rate of change less than ± 5%, for example, it is preferable to be less than ± 2%, be less than ± 1% or less than ± 0.5%.

It realizes that the prior art of the low rate of change of nylon salt is concentrated on using multiple reactors to adjust in salting liquid AA:HMD molar ratio and HMD concentration.This concentrates the flowing at least partially due to the variability and difference of the bulk density of AA powder Property, lead to the unpredictability of intrinsic AA powder feed.When using volume feeder come by AA powder feed to reactor, Expand the variability of AA powder bulk density.Due to the high-melting-point of AA, AA usually is provided with powder, which increase the difficulties of processing AA Degree.In order to reduce the difficulty of processing AA powder, the present invention forms the liquid PBA solution comprising AA.By by AA powder and liquid Body diamines is in conjunction with preparing PBA solution.AA powder usually has the average-size between 75 and 500 microns, and such as 100 and 300 Between micron.There is more tiny powder substantially bigger surface area and particle to contact, and which results in agglomerations.Preferably, AA Powder contains the particle less than 75 microns less than 20%, such as less than 10%.Due to being typically based on volume, it is direct with powder morphology It is passed through in reactor to measure AA powder, the variation of powder size will affect dissipating for the AA powder being fed into nylon salt reactor Packing (bulk packing) and density.The variation of these bulk packages and density then will lead to the pH in nylon salt solution The variation of value and the molar ratio of AA ratio HMD.In view of this variation, the solution of the prior art is to arrange nylon salt series connection anti- Answer device.For example, with reference to U.S. Patent Publication 2012/0046439 and 2010/0168375.This traditional method uses goal standard Measurement method and by monomer feed into series reactor.But this method requires multiple reactors, measurement method and tune Section method, this will increase cost and limit production rate.In addition, this conventional method is more likely to be appropriate for batch production rather than connects Continuous production.Finally, these conventional methods cannot predict pH value and/or salinity using model, thus constantly adjust so that Nylon salt solution reaches goal standard.

Effect with the distribution of the relevant particle size of AA powder and particle size that are fed into nylon salt technique is logical It crosses using multiple reactors and adds AA and HMD and solve in the prior art.It has been found that by being measured based on weight AA powder, rather than measured with volume, it can greatly reduce the variability of AA powder feed rate.In some aspects, AA powder Feed rate can change in the range of being less than ± 5% compared with target AA powder feed rate, be, for example, less than ± 3% or be less than ±1%.Using this stable charging, disclosed method is able to use a single-reactor, and does not have to multiple tandem reactions Device, to form the nylon salt solution of goal standard.There is limitation in the ability due to adjusting monomer, therefore, it is difficult to not stablizing AA powder feed and control nylon salt solution compared to target pH using single reactor under high continuous production rate The change rate of value and target salinity.Charging of stablizing with AA powder enables the method to control using before HMD Rate is presented, and makes it possible to adjust compensation HMD and realizes target ph to adjust pH value.Advantageously, it is contemplated that specific embodiment party Case discloses simpler design than existing to provide by the quantity of the unit operation in reduction method.Therefore, this disclosure Method be omitted and be previously considered to be required step.It reduce the occupied area of equipment and fund costs.Obtained Buddhist nun Imperial salting liquid then can be polymerize to form required polyamide.

In order to realize the industrial acceptable production manufactured of nylon salt, it can be used continuous method molten to produce nylon salt Liquid, the nylon salt solution realize target ph and target salinity.Batch production ask that significant bigger container and Reactor, this can not be compared with the throughput rate realized by lesser continuous producing apparatus.With uniform in polymerization PH value and the nylon salt solution of salinity start to be advantageous.Slight variation can cause the production quality in polymerization to be asked Topic, this needs the adjustment of additional monitoring, control and polymer process.

Fig. 1 provides the general overview figure of the method for the production nylon salt solution an of embodiment according to the present invention. As shown in Figure 1, nylon salt solution production method 100 includes that AA powder 102 is fed into loss in weight feeder 110, production meter The AA powder feed 139 of the metering is passed through the container 302 including dispersing head 304 by the AA powder feed 139 of amount.Water and HMD Respectively by pipeline 103 and 104 also enter container 302 with formed be rich in AA PBA solution 306, alternatively referred to as crude salt solution or Feedstock solution.In one embodiment, PBA solution 306 has the molar ratio of the AA ratio HMD between 2:1 and 5:1, such as Between 2:1 and 3:1, the molar ratio of the AA ratio HMD is based on free and chemical bonding AA and HMD.Keep PBA solution 306 be liquid, without forming slurry or solid.As further described below, in being introduced into continuous stirred tank reactor 140 it Before, PBA solution 306 is storable in tank 184.More mixing are allowed in this way, are allowed before forming nylon salt solution The inventory of the AA of storage also allows that PBA solution and nylon salt solution is produced independently.By using liquid PBA solution 306, no It is introduced directly into continuous stirred tank reactor 140 with by AA powder 102.PBA solution 306 is transmitted to continuous stirred tank reactor In 140.In addition, water, by pipeline 103 ', HMD is fed in continuous stirred tank reactor 140 by pipeline 104 '.In some realities It applies in mode, before being fed into reactor 140, pipeline 103 ' and 104 ' can be merged (not shown).

The liquid containing nylon salt solution is withdrawn from from reactor 140 by recirculation circuit 141, and is back to reactor 140.If desired, additional HMD can be added at crosspoint 142 from pipeline 107, referred to herein as compensation HMD, to adjust nylon salt PH value.Nylon salt solution is withdrawn from crosspoint 143 from recirculation circuit, and enters pipeline 144.Nylon in pipeline 144 Salting liquid removes impurity through filter 190 and is collected in storage tank 195.Nylon similar to PBA solution 306, in storage tank 195 Salting liquid not will form slurry or solid.It in general, these impurity may include corrosion metal, and may include carrying out AA powder 102 freely Monomer feed impurity.Nylon salt solution is moved into polymerization technique 200 through pipeline 199.Nylon salt solution can be reserved in storage In tank 195, until need to be used to polymerize.In some embodiments, the storage tank 195 is transportable.

Nylon salt solution equipment

In one embodiment, the present invention relates to the continuation methods for producing nylon salt solution, comprising: with weight Meter, measures the dicarboxylic acid powder from loss in weight feeder to feed conduit, and dicarboxylic acid powder can be delivered to by the feed conduit Container with dispersing head；First feed stream of diamines is passed through in container, with formed containing 32 weight % and 46 weight % it Between dicarboxylic acids, the dispersion between diamines and 39 weight % and 57 weight % water between 11 weight % and 15 weight %；50 DEG C and 60 DEG C at a temperature of between heat the dispersion, to form PBA solution；By the second charging object of PBA solution and diamines Stream introduces continuous stirred tank reactor, to form nylon salt solution；Nylon salt is continuously withdrawn from from continuous stirred tank reactor Solution is simultaneously passed directly into storage tank, and wherein the salinity of nylon salt solution between 50 weight % and 65 weight % and includes to have Dicarboxylic acids/diamine salts of target ph；And the feed-rate variation rate of control dicarboxylic acid powder, so that the pH of nylon salt solution Extremely change in the range of ± the 0.04pH of target pH.Preferably, method of the invention allows PBA solution to have less than ± 5% The low rate of change of concentration of adipic acid, e.g. preferably smaller than ± 2%, less than ± 1% or less than ± 0.5%.

AA powder feeder based on weight

Fig. 2 provides the further details of PBA solution 306 of the production rich in AA.Using loss in weight feeder 110 by AA Powder 102 is fed into container 302.Loss in weight feeder 110 measures AA powder 102 to produce and have low variational charging speed The AA powder feed logistics 139 of rate, and it is able to solve the variation of the density of AA powder 102 in fill process.As it appears from the above, AA powder The bulk density and mobility at end 102 are likely to vary greatly, and are led to the imbalance for introducing molar ratio and are produced inhomogenous pH value Nylon salt solution.The present invention is relative to the volume feeder that can not achieve the low variability feed rate of AA powder and other kinds of Feeder is advantageous.For purposes of the present invention, the low variability feed rate of AA powder is the target feed in AA powder In the range of ± the 5% of rate, in the range of such as ± 3%, in the range of ± 2%, or in the range of ± 1%.For mesh of the invention , the variability of feed rate refers to the average rate of change in continuous operation.Due to the low variability of AA powder feed rate, AA Feed rate be stable and predictable.The low rate of change of AA powder feed rate allows to be formed with low rate of change The formation of the PBA solution of concentration of adipic acid.Stable and predictable AA powder feed rate allow suitably setting diamines and The feed rate of water, so that single reactor can be used to realize target ph and/or target salinity.Due to relative to mesh The low variability of feed rate AA powder feed rate is marked, therefore does not need additional reactor to mix and adjust.

Generally, loss in weight feeder 110 is operated in supplemental stages to load hopper 111, in charging stage distribution hopper Content in 111.Preferably, at least 50% time, preferably at least 67% time, the supplement-charging stage Period is enough to receive the feedback signal from loss in weight feeder 110.In one embodiment, the time of supplemental stages can be lacked In the total time of the 20%(such as charging and supplemental stages of total cycle time), such as it is less than 10% or less than total period of total cycle time The 5% of time.The time in supplemental stages and total period depends on throughput rate.Receiving during the charging stage, in hopper 111 Object is assigned to feed pipe 112, and AA powder is delivered to continuous stirred tank reactor through pipeline 139 by the feed pipe 112 In 140.In addition, remaining AA can also be assigned into feed pipe 112 in hopper 111 during supplemental stages, so feed The continuous supply of the reception AA powder of pipeline 112.Controller 113 can be used to control loss in weight feeder 110.Controller 113 can For distribution control system (distributed control system, DCS) or programmable logic controller (programmable logic controller, PLC), the programmable logic controller can be defeated according to what is received Enter information and carrys out output function.In one embodiment, multiple controllers may be present, be used for the multiple assembly of system.For example, PLC can be used to regulate and control supplemental stages, and controlled according to the targeted rate being arranged in DCS through feed pipe 112 using DCS Feed rate.

As shown in Fig. 2, AA powder 102 is loaded into supply container 115 by conveyer system 114.Conveyer system 114 can be machine Tool conveyer system or pneumatic transfer system, conveying come from container bag, liner container bag, liner box container or hopper track The adipic acid of vehicle depot.Mechanical transmission system may include screw rod and haulage chain.Pneumatic transfer system may include closed conduit To use next compressed air, evacuated air or closed circulating nitrogen gas that AA powder 102 is delivered to supply container 115.One In a little embodiments, conveyer system 114, which can provide, picks functor to be crushed the knot of AA powder when loading supply container 115 Block.Supply container 115 can be cylinder-shaped, trapezoidal, square or other suitable shapes, and have import 116 at top.With oblique The shape on side helps that AA powder 102 is assisted to flow out supply container 115.The top edge of supply container 115 can be lower than system ground 130 or more 20 meters of elevation (m), such as preferably shorter than 15m.System ground elevation 130 refers to being support on it for producing Buddhist nun The plane of the various equipment of imperial salting liquid, and it is commonly defined as the plane that no monomer passes through it.System ground elevation can be On the import of CSTR.Since the height relative to system ground elevation 130 of supply container 115 is lower, it is therefore desirable to less Energy come driving transmission system 114 and load supply container 115.

Supply container 115 also has low valve 117, when it is closed, forms one for accommodating the inner cavity of AA powder 102. Low valve 117 can be rotary table feeder, screw-feeder, rotary flow device or the coupling apparatus including feeder and valve. When inner cavity filled with AA powder 102, low valve 117 can be kept to close.During supplemental stages, low valve 117 can be opened, to be based on AA powder 102 is sent to hopper 111 by volume.When AA powder is sent to hopper 111 by low valve, AA powder can be loaded into confession To in container 115.Low valve 117 may include one or more ailerons that sealing can be formed when low valve is closed.In an embodiment party In formula, conveyer belt (not shown) may be present, for AA powder 102 to be delivered to hopper 111 from supply container 115.In other realities It applies in mode, supply container 115 can convey AA powder 102 by gravity.The loading of supply container 115 can be independently of hopper 111 Loading.

Supply container 115 can have a capacity greater than hopper 111, preferably have preferably at least twice or be three times in hopper 111 Capacity.The capacity of supply container 115 should be enough to supplement the whole volume of hopper 111.Compared to hopper 111, AA powder 102 can The longer time is accommodated in supply container 115, and according to humidity, AA powder 102 is likely to form agglomeration.It can be by holding in supply The mechanical rotator of 115 bottom of device or vibrator (not shown) are crushed the agglomeration.

The top edge of hopper 111 can be less than 15m, such as preferably less than 12m in 130 or more system ground elevation.Hopper 111 can For cylinder-shaped, trapezoidal, square or other suitable shapes, and there is import 118 at top.Preferably, the inner surface of hopper is steep Directly, to prevent the bridge joint of AA powder.In one embodiment, the inner surface has 30 ° to 80 ° of an angle, for example, 40 ° extremely 65 ° of angle.The inner surface can be U-shaped or V-type.Hopper 111 can also have it is removable with porose cover board (not shown), The hole is used for import 118 and ventilation opening.Hopper 111 is mountable to conduit 119, the conduit 119 by hopper 111 be connected into Expect conduit 112.In one embodiment, hopper 111 has equal volume to maintain desired throughput rate.For example, material Bucket 111 can have at least 4 tons of capacity.The maximum gauge of conduit 119 is less than the maximum gauge of hopper 111.As shown, conduit 119 have rotary table feeder 120 or similar conveying device, for distributing extremely the content in hopper 111 by outlet 129 Feed pipe 112.Rotary table feeder 120 can be operated under unlatching/close pattern, or can be used as the function of required feed rate To control the speed of rotation.In another embodiment, conduit 119 can not have internal feeding mechanism.It is fed according to weight-loss type The type of device, rotary table feeder 120 can massage paddle or oscillator by external and replace, and the external massage paddle can be by discharge from material Bucket 111 is distributed to feed pipe 112.Outlet 129 can have mechanical system to be crushed the agglomeration of AA.In another embodiment In, loss in weight feeder 110 can have drier or dry gas purging device (not shown), to remove moisture from AA powder, To prevent AA powder from agglomerating in hopper 111 and form blocking.

Weight measurement subsystem 121 is connect with hopper 111.Weight measurement subsystem 121 may include multiple sensors 122, It is used for weighing bucket 111 and provides the signal for indicating weight to controller 113.In some embodiments, can there are three pass Sensor or four sensors.Sensor 122 can be connect with the outside of hopper 111, and in view of hopper 111 and any other and material The initial weight of the equipment of 111 connection of bucket, the sensor 122 can be with taring.In another embodiment, sensor 122 The lower section of hopper 111 can be placed in.Based on the signal from weight measurement subsystem 121, controller 113 control supplemental stages and into The material stage.Controller 113 compares the weight measured under regular intervals, is distributed whithin a period of time with determination to feed conduit The weight of 112 AA powder 102.Controller 113 goes back the speed of rotation-controlled auger 123, is described below.

In other embodiments, weight measurement subsystem 121 can be placed in hopper 111, conduit 119 and feed pipe 112 Lower section, the weight of the material in these positions for measuring loss in weight feeder 110.

Feed pipe 112 is placed in the lower section of conduit 119, and receives AA powder 102.In one embodiment, feed pipe Road 112 can be connect with conduit 119.The plane of the extensible outlet 129 basically perpendicular to conduit 119 of feed pipe 112, or from Plane simultaneously can be extended out an angle between 0 ° and 45 ° to container 302, such as the angle between 5 ° and 40 °.Feed pipe 112 Spiral 123 is rotated at least one, AA powder 102 is transported through into open outlet 124, and enter reactor 140.Rotation Spiral 123 is driven by motor 125, and may include worm screw.Twin worm structure can also be used.Motor 125 is with speed that is fixed or changing Degree rotates spiral 123 to drive.In one embodiment, feed pipe 112 is passed with low variational rate by AA powder 102 It conveys into container 302.The feed rate of AA can be adjusted according to desired yield.This allows to establish fixed AA charging speed Rate, and use model described herein, then change the feed rate of other solution components with realize desired salinity and/or PH target value.Controller 113 receives the feedback signal from loss in weight feeder 110, and adjusts the speed of rotation spiral 123. Controller 113 also based on the signal from weight measurement subsystem 121, adjusts the feed rate of feed pipe 112.Give rotation spiral shell The command signal of rotary drill 123 will affect motor speed (as increased, keeping or reducing motor speed) to realize the weight damage of setting It loses.

In other embodiments, feed pipe 112 described herein can be any equivalent controllable type feeder, Such as belt feeder, van-type feeder, feed disk, oscillatory type feeder.Feed pipe 112 may also include Vibrant buffer Device (not shown).In addition, feed pipe 112 can have 1 or multiple gas port (not shown)s, for injecting nitrogen except deoxidation Gas.

Hopper 111 may also include high-order probe 127 and low level probe 128.It is to be appreciated that for convenient and fast purpose, It shows a high position and a low level probe, but may exist multiple probes.The probe can be with weight measurement subsystem 121 It is used in combination.For purposes of the present invention, the probe can be level point indicating gage or capacitive proximity sensor.Adjustable material-saving The position of high-order probe 127 and low level probe 128 in bucket 111.High-order probe 127 is located at the near top of hopper 111.When logical When crossing high-order probe 127 and measuring the material in hopper 111, supplemental stages are completed and start the charging stage.On the contrary, low level probe 128 are located at the lower section of high-order probe 127, and closer to the bottom of hopper 111.The position of low level probe 128 may make surplus enough The AA powder 102 of surplus can be distributed in supplemental stages.When low level probe 128 detects do not have material in hopper on its position When, start supplemental stages.As described above, can continue to feed during supplemental stages.

AA solid can be corrosive.Loss in weight feeder 110 can be constructed by corrosion resistant material, the corrosion resistant Corrosion material such as austenitic stainless steel, or such as 304,304L, 316 and 316L or other suitable corrosion resistant materials, with One economically feasible balance is provided between equipment life and fund cost.In addition, resistant material can prevent product Corrosion contamination.Other resistant materials are preferably attacked than carbon steel more resistant to AA.The HMD of high concentration, such as larger than 65% HMD, to carbon Steel does not have corrosivity, therefore carbon steel can be used for storing the HMD of concentration, and stainless steel can be used for storing the HMD of more dilute concentration.

Although showing an illustrative loss in weight feeder 110, other acceptable loss in weight feeder can include: The type of Acrison402/404,403,405,406 and 407；Merrick570 type；K-Tron KT20,T35,T60,T80,S60, S100 and S500 type；And Brabender Flex Wall^TMPlus and Flex Wall^TMClassic.Acceptable weightlessness Formula feeder 110 should be able to realize the feed rate of enough continuous comercial operations.For example, feed rate can be at least 500Kg/hr, for example, at least 1000Kg/hr, at least 5000Kg/hr or at least 10000Kg/hr.In embodiments of the present invention Higher feed rate also can be used.

Container with dispersing head

When dissolving AA powder, a kind of homogeneous mixture of the invention is as the PBA solution containing HMD and water.Water Help to dissolve AA, because HMD is not enough to dissolve AA powder.The freezing point for the mixture that water also can be beneficial to reduce.Oneself two The solubility of acid in water is lower, thus in the presence of no HMD, it is desirable that high storage temperature.

It is back to container 320, in one embodiment, container 320 can be used as batch or continuous high-shear mixer To operate.Essentially all of AA needed for nylon salt solution is passed through into container device 302, therefore in continuous stirred tank reactor There is no AA powder to need to dissolve in 140.The dispersion 308 rich in AA that container 302 produces, the dispersion rich in AA can be made Continuous stirred tank reactor 140 is pumped to for PBA solution 306.It is advantageous which improve the AA powder for being fed into reactor 140 The homogeneity at end, and significantly increase the storage capacity of adipic acid in technique.For example, with liquid PBA solution 306, AA powder 102 It is storable in the cabinet (not shown) being located within ground elevation 13015m, for example, being more preferably located at ground elevation 13010m Within cabinet in.Therefore, the loading of cabinet is more easily realized.

Container 302 can be mixing chamber, bucket or tank, such as continuous stirred tank reactor, can have one or more dispersions First 304.Compared with Rotor-stator mixers, preferably dispersing head provides improved circulation to form dispersion.Advantageously, making AA powder 102 is dispersed in liquid HMD104 and water 105 with container 302.

Each dispersing head 304 is connect by axis 312 with motor 310.The speed of motor 310 can be adjusted according to expectation to generate The mixing of enough reaction-ure mixtures.Dispersing head 304 can be fixed on axis 312, and under the liquid level being maintained in container 302 Side.In some embodiments, dispersing head 304 can be removed from axis 312, so that can dismantle and/or replace between dispersing head It changes.United States Patent (USP) 5407271 describes suitable dispersing head, entire content and is openly incorporated by reference the present invention In.Reactant is added in the content of container 302, to form reaction-ure mixture 314.Dispersing head 304 provides high shear Power is mixed to form the dispersion comprising homogeneous mixture.The size and shape of dispersing head 304 can be different.In an embodiment In, reaction mixture 314 is sucked into dispersing head 304 to inner cavity, and is mechanically torn by impeller blade or impeller tooth. The top and bottom of dispersing head 304 can provide mechanical tearing.The top and bottom that reactant is pumped to dispersing head 304 can be produced Life concentrates on interior intracavitary high high-speed counter-current, so generates high turbulent flow and hydraulic shear shear force.Centrifugal pressure forces content to pass through The side mouth of dispersing head 304 is discharged.Can make the edge of opening becomes sharply, to provide further mechanical shear stress.It is high Speed excludes object and is combined with reaction mixture 314 to provide additional hydraulic shear shear force and circulation.

In an optional embodiment, axis 312 may include one or more hybrid blade (not shown)s with further It helps mixed.

Container 302 can also have one or more gas port (not shown)s, for injecting nitrogen to remove oxygen.If made It is protected with blanket of nitrogen, the nitrogen for being passed through gas port can be suitably containing the humidity less than technique unit surrounding air.Such as it can be used Drying nitrogen.

Due to the low-solubility of AA in water, the AA powder for needing heat to be dissolved in water maintains posture.At one In embodiment, one or more heaters can be provided in recirculation circuit 322.Maintain heat necessary to liquid can be with water Concentration is different and changes.The present invention uses HMD and water with further hydrotropy AA, and forms the PBA solution 306 containing mixture, The mixture can store at low temperature.Advantageously, the low temperature of mixture, which reduces, is generally used for preventing the additional of slurry formation Energy.In one embodiment, PBA solution 306 can be maintained at the temperature between 50 DEG C and 60 DEG C with homogeneous phase solution, such as 55 DEG C and 60 DEG C between temperature.Within the limited time, which can be slurry, until acid has time enough complete Dissolution, at this moment the mixture becomes clarification, homogeneous solution.The condition and temperature for setting composition, so that initial slurry is not It can be maintained at slurry state, but be transformed into clarification, homogeneous solution.The solution min of AA depends on variable, and this variable is such as Energy, temperature etc..

In one embodiment, water 103 and HMD104 can be passed through container 302 through liquid-inlet 316, and use weight-loss type The measurement of feeder 110 passes through the AA powder 102 of solids inlet 318.Liquid-inlet 316 and solids inlet 318 can be in containers 302 Top.For purposes of the present invention, needed for nylon salt solution of the salinity between 50% and 65% needed for being formed at least 80% water is passed directly into container 302, preferably at least 90% required water.Generally, additional water can be added as shown in Figure 3 In reactor vent condenser 131, or as compensation charging 103 ', such as the water of second part, it is added in reactor 140, with Salinity needed for realizing.Be passed through container 302 HMD104 can the HMD needed for forming nylon salt solution 10% and 60% it Between, such as between the 25% of required HMD and 45%.Be passed through container 302 HMD104 can be it is anhydrous or containing 0 weight % and Water between 20 weight %.The temperature for being passed through the HMD104 of container 302 can be enough to prevent the solidification of HMD, and be usually above 40 DEG C, Such as or higher than 45 DEG C.Water can be added at room temperature, to form the dilution HMD solution 320 with the temperature higher than 40 DEG C, such as Higher than 45 DEG C.In one embodiment, dilution HMD solution 320 includes the HMD and 70 between 15 weight % and 30 weight % The water of weight % to 85 weight % preferably comprises HMD between 20 weight % and 30 weight % and 70 weight % to 80 weight %'s Water, the dilution HMD solution 320 can be passed into container 302.

In one embodiment, since dispersing head 304 generates high shear force mixing, in the presence of fresh HMD and water, AA powder can disperse and dissolve in container 302.Therefore, the salt not in the future in autoreactor 140, storage tank 184 or storage tank 195 is molten Liquid, which is passed through in container 302, dissolves AA powder.The recycling of salting liquid makes the production capacity of this method reduce up to 50%.

Container 302 forms tool homogeneous dispersion 308, and the composition of the dispersion is alterable, generally comprise 32 weight % and The water of AA, 11 weight % between 46 weight % and the HMD between 15 weight % and 39 weight % and 57 weight %, further preferably Between AA, 13 weight % between 40 weight % and 46 weight % and HMD and 41 weight and 47 weight % between 15 weight % Water.In one embodiment, the weight of the AA in PBA solution is at least twice of the HMD weight in PBA solution.At one In embodiment, dispersion 308 includes the balance salt between 25% and 50%, such as adipic acid hexamethylene diamine salt and 15% and 40% Between free adipic acid.The solid concentration of dispersion can be less than 60%.Solid concentration includes balance salt and free AA.In general, point Granular media does not contain any free HMD, and all HMD for being passed through container 302 are chemically bonded with balance salt.PBA solution 306 has Component identical with dispersion 308 and solid concentration.

In one embodiment, reaction-ure mixture 314 can continuously recycle in circuit 322.In order to further AA powder is helped to disperse and grinds, circuit 322 may include direct insertion disperser 324, the continuous processing for dispersion 308. Direct insertion disperser 324 can be high shear mixer and disperser.Reaction-ure mixture 314 enters and leads to through import 326 It crosses internal mechanical stator, impeller and blade to be sheared, to form homogeneous mixture.It is described to generate that multiple mechanical steps may be present Shear action.For example, reaction-ure mixture 314 can be by rotating vane, and works as reaction-ure mixture 314 and pass through in stator Long and narrow hole and when being sheared, into stator.Dispersion 308 can enter storage tank 184 by fluid level control valve 328.Dispersion 308 A part can also be recycled system to container 302.In some embodiments, the external heating and cooling in circuit 322 can be used To control the temperature of container 302.There is no suspended crystal, the temperature in circuit 322 and the content in container 302 in preferably remaining homogeneous Degree should be at 50 DEG C or more, such as 50 DEG C to 60 DEG C or 55 DEG C to 60 DEG C.It can be led to by controlling to flow through the fluid in circuit 322 and/or adjust Enter logistics or the hot water of circulation loop heater to control temperature.

In one embodiment, when the liquid feedstock through liquid-inlet 326 enters direct insertion mixer 324 and generates low Intermediate pressure section (sub-atmospheric pressure) and by its generate suction when, the liquid feedstock through liquid-inlet 326 can be higher than atmospheric pressure.To the greatest extent Pipe Fig. 2 shows a direct insertion mixer 324, in some embodiments, the multiple straight of parallel or series arrangement may be present Insert formula mixer.Suitable commercially available direct insertion mixer may include Admix DYNASHEAR^TMMixer, QUADRO YTRON^TM Mixer, INOXP^TMDirect insertion mixer ME4100, IKA^TMWorks mixer, GERICKE^TMMixer, YSTRAL^TMMixing Device and SILVERSON^TMMixer.

It in some embodiments, can be in circuit 322 using pump, such as centrifugal or positive-displacement pump, to provide reactant The further mixing of mixture 314.Pump (not shown) is also used other than using direct insertion mixer 324, or if is made Sufficient mixing has been obtained with dispersing head 304, then has been come independently of direct insertion mixer 324 using pump.

In some embodiments, recirculation circuit 322 does not connect directly to measure or sample dispersion with any analyzer The salinity and pH value of body 308.In some embodiments, mass flowmenter can be used to measure density and temperature and push away Disconnected pH value.PH value is adjusted in addition, being added by recirculation circuit 322 corresponding to pH value measurement without monomer.

As shown in Fig. 2, the recycled circuit 185 of dispersion 308 enters storage tank 184.As shown, recirculation circuit is through one A or multiple internal spray mixer 186(such as displacer) it is back to the lower part of storage tank.In one embodiment, internal spray Penetrate the position that mixer 186 can be placed between the bottom 0.3 and 1.5 meter from storage tank 184, the position preferably between 0.5 and 1.5 meter It sets.One or more jet mixers 186 can be used to mix dispersion or mix into storage tank 184.It can incite somebody to action as needed PBA solution 306 can take out from recirculation circuit 185, and be passed through continuous stirred tank reactor 140.

In some embodiments, direct insertion mixer 324 can have a pressure difference less than 200kPa, such as less than 170kPa, Or it is less than 100kPa.Kinetic current by dispersion 308 as the jet mixer 186 in storage tank 184 uses, it may be required that 175 Higher pressure between 350kPa.In order to increase the pressure of the dispersion 308 by fluid level control valve 328, can disperse There are an external displacers 187 for the engaging portion of body 308 and recirculation circuit 185.Recirculation circuit 185 is as external row The kinetic current of device out provides pressurization for dispersion 308.In another embodiment, booster pump (not shown) can be used to replace Dispersion is drained into storage tank 184 by jet mixer.

In one embodiment, recirculation circuit 185 does not connect directly to measure or sample storage with any analyzer Dispersion, i.e. PBA solution 306.Due to be rich in AA, PBA solution 306 is more Plus acidic, and with following nylon salt solutions It compares, it is more insensitive to component difference.Therefore, the pH measurement of the liquid being not responsive in storage tank 184 adjusts PBA solution 306. Under the premise of the charging of low variational stable AA powder, PBA solution may make to be adequately controlled, without monitoring Or the content in control storage tank 184.

Storage tank 184 can have the capacity of the solution of the PBA with the inventory for accommodating up to 5 days, more preferably up to 3 days libraries It deposits.Although illustrating only a storage tank 184, it is to be understood that multiple storage tanks can be used to guarantee enough inventories.This makes Obtaining container 302 can operate independently to dissolve adipic acid and by obtained dispersion 308 in the advance for forming nylon salt solution Row storage.Storage tank 184 can be maintained under an inert atmosphere, such as nitrogen atmosphere in the case where atmospheric pressure or a little higher than atmospheric pressure Under.Storage tank 184 can have outlet 174 for removing removing exhaust gas.

Storage tank 184 can be maintained to the temperature between 50 DEG C and 60 DEG C, the temperature between preferably 55 DEG C and 60 DEG C.It is advantageous It is that the lower temperature for storage can improve operating efficiency, reduces the degradation of salt and reduce energy consumption.For example, do not store and Directly charging PBA solution can provide 2-8 hours inventories into continuous stirred tank reactor 140, and by PBA solution from storage tank 3-5 days inventories can be obtained in charging in 184, this is an advantage of the invention.It reduce the losses due to PBA solution feed And to the potentially possible of the interference of continuous stirred tank reactor 140.Interior heater 188 may be present in storage tank 184.In addition, Recirculation circuit 185 can have one or more heaters 189, for providing heat for storage tank 184.It is adjustable to flow to internal add Hot device 188 or one or more steam of heater 189 or the flow velocity of hot water, to maintain the required temperature of storage tank 184.

In one embodiment, do not measured directly by the way that monomer to be added in PBA solution 306 and/or storage tank 184 or Adjust the pH value of PBA solution 306 in storage tank 184.In one embodiment, the introducing of PBA solution 306 continuous stirred tank is anti- Before answering in device 140, the pH value of measurement PBA solution 306 is not needed.In some alternative embodiments, addition can be used PH value measuring instrument.

As described below, a series of quantity that PBA solution not only reduces salt reactors is formed using container 302, and PBA solution additionally advantageously improves the inventory of the adipic acid in technique, and in the significant low temperature item decomposed for reducing salt Target salt inventory of a part as semi-finished product inventory is assumed responsibility under part, is improved and is fed into continuous stirred tank reactor 140 AA charging homogeneity, and it is same as polymerization modified additive, eliminate separated interval PBA equipment.

Reactor

In an embodiment of the invention, from PBA in single continuous stirred tank reactor 140 as shown in Figure 3 Solution 306 is prepared into nylon salt solution.Continuous stirred tank reactor 140 can produce enough turbulent flows, homogeneous for producing Nylon salt solution.For purposes of the present invention, " continuous stirred tank reactor " refers to a reactor without including more A reactor.In addition, single reactor does not include container 302.The present invention can realize that homogeneous nylon salt is molten in single container Liquid is without requiring multiple tandem reactors as used in conventional method.Suitable continuous stirred tank reactor is that single container is anti- Device is answered, such as non-tandem reactor.Advantageously, it reduce with the capital input in commercial mass production nylon salt solution. When being used in combination with loss in weight feeder described herein, it is molten that continuous stirred tank reactor can be realized homogeneous nylon salt Liquid realizes target ph and target salinity.

Nylon salt solution is withdrawn from from reactor 140, and is fed directly to storage tank 195.It is reacted from continuous stirred tank It withdraws from and enters between in storage tank 195 in device 140, no longer monomer (AA or HMD) is introduced into nylon salt solution.More specifically, Nylon salt solution is withdrawn from from recirculation circuit 141 and enters conduit 144, and is added without monomer in conduit 144.One side Face, conduit 144 do not have the import for introducing additional monomers, and the additional monomers may include dicarboxylic acids and/or diamines.Cause This, does not adjust the pH value of nylon salt solution further by the way that additional monomers are introduced into conduit, does not pass through addition volume especially Outer HMD is adjusted.As needed, can nylon salt solution additionally be mixed and is filtered, as described herein, monomer can only led to Enter in single continuous stirred tank reactor.Therefore, the disclosed method can not need the series connection of multiple containers and recognize before this The consecutive steps for measuring and adjusting for necessary pH value, and metering balance stable between AA and HMD is kept, to manufacture nylon 6, 6。

Continuous stirred tank reactor 140 can have the draw ratio between 1 and 6, draw ratio such as between 2 and 5.It can be used Following material come build reactor 140 between equipment life and fund cost provide an economically feasible balance, institute Material is stated to be selected from by Hastelloy C alloys (Hastelloy C), aluminium, austenitic stainless steel (austenitic stainless Steel, such as 304,304L, 316 and 316L) or the group that constitutes of other suitable anticorrosion materials.It can be by considering continuously to stir The temperature in kettle reactor 140 is mixed to select material.Residence time in continuous stirred tank reactor 140 can according to its size and Feed rate and different, usually less than 45 minutes, such as less than 25 minutes.Liquid is withdrawn from and is entered from lower part outlet 148 and followed again In loop back path 141, and nylon salt solution is withdrawn from from conduit 144.

Generally, suitable continuous stirred tank reactor includes at least one monomer import to introduce HMD and/or water and one A import for being used to introduce PBA solution.The import is passed directly into the top of reactor.In other embodiments, it can be used Suction pipe carrys out charged monomer in liquid level.Multiple imports may be present, for each component to be introduced into reaction medium.Fig. 3 shows one A illustrative reactor 140.When using PBA solution, the aequum for being used for the AA of nylon salt solution is preferably passed through container 302 to generate PBA solution 306.Therefore, continuous stirred tank reactor 140 preferably has PBA import 145 and HMD import 146 simultaneously And it does not introduce a solid into continuous stirred tank reactor 140.HMD can be introduced with pure HMD104 ' or in form of an aqueous solutions, The aqueous solution contains the HMD(between 20 weight % and 100 weight % for example containing the HMD between 65 weight % and 100 weight %), And contain the water (such as containing the water between 0 weight % and 20 weight %) between 0 weight % and 80 weight %.It is passed through continuous stirred tank The HMD104 ' of reactor 140 is to be formed between 20% and 70% of HMD needed for nylon salt solution, 30% He of for example, required HMD Between 55%.HMD104 ' can be introduced by import 146, the import 146 is adjacent with the import 145 of PBA solution 306.Due to right Water can be introduced in multiple positions not to the stringent of pH value in the franchise of salinity, such as described herein, import can be passed through 145 and/or 146 and/or water is introduced by pump 149.Optionally, it can exist for the import 147 for being introduced separately into water.It can be with Water is introduced by reactor recovery tower 131.In some respects, recovery tower 131 can be vent condenser.Due to most water with PBA solution 306 introduces, therefore needs a small amount of water only to realize required salinity.

Liquid in reactor 140 is continuously withdrawn from, and passes through recirculation circuit 141.Recirculation circuit 141 may include one A or multiple pumps 149.Recirculation circuit 141 may also include Temperature-controlled appliance, temperature measurement equipment and controller, described, temperature Degree control equipment is, for example, coil pipe, collet or the device including heat exchanger.Temperature-controlled appliance controls in recirculation circuit 141 Nylon salt solution temperature, with prevent nylon salt solution boil or formed slurry.When introducing additional HMD by pipeline 107, such as When compensating HMD, preferably at the upstream crosspoint 142 of one or more pumps 149 and the upstream of any pH or salt concentration analyzer Introduce HMD.As described in further discussing the present invention, compensation HMD107, which contains, forms 1% and 20% of HMD needed for nylon salt solution Between, for example, between the 1% of required HMD and 10%.Crosspoint 142 can be the inlet interface into recirculation circuit 141.It removes The circulation liquid, pump 149 also work as the second mixer.Pump can be with the following functions simultaneously, i.e., will compensate HMD It is introduced into recirculation circuit 141, and compensation HMD is mixed with the liquid withdrawn from from reactor.The pump can be selected from By vane pump, piston pump, flexible member pump, lobe pump, gear pump, peripheral piston pump and screw pump the group constituted.Some In embodiment, pump 149 can be placed at crosspoint 142.In other embodiments, as shown, pump 149 can be in crosspoint 142 downstream, but before crosspoint 143.It is preferred that the second mixing occurs after adding all HMD, including pass through pipeline 107 addition compensation HMD, and before any analysis or withdrawing in storage tank 195.In an optional embodiment, it can pump One or more static mixers are set in the recirculation circuit 141 in 149 downstream.In Perry, Robert H., and Don W.Green.Perry’s Chemical Engineers’Handbook.7th ed.New York:McGraw-Hill,1997: Illustrative static mixer is further described in 18-25to18-34, is incorporated into the present invention by reference.

At crosspoint 143, nylon salt solution can be withdrawn in conduit 144.Residence time in conduit 144 can be according to storage The position of tank 195 and filter 190 and it is different, usually less than 600 seconds, be, for example, less than 400 seconds.In one embodiment, may be used Operation valve 150 controls the pressure of nylon salt solution.Although illustrating only a valve, but it is understood that, it is being recirculated back to Additional valve can be used in road 141.There is no monomer (such as AA or HMD) to be introduced into the downstream in crosspoint 143 or enters conduit 144 In.In addition, under normal handling conditions, no monomer is introduced into storage tank 195.

Recirculation circuit 141 may also include heat exchanger 151, for controlling the temperature of liquid in reactor 140.It can pass through It is controlled using the temperature controller (not shown) in reactor 140 or at the outlet of continuous stirred tank reactor 140 (not shown) Make the temperature.Inner heat exchanger can be used, such as coil pipe or jacketed reactor (not shown), to adjust the temperature of the liquid Degree.Cooling water can be provided for heat exchanger 151, the cooling water maintains the freezing point of the salt of given concentration or more.At one In embodiment, heat exchanger can be indirect shell heat exchanger or tubing heat exchanger, spiral or plate and frame heat exchanger, Or the reboiler for recycling heat from reactor 140.The temperature of reactor 140 maintains the range between 60 DEG C and 110 DEG C, with Prevent slurry formation and Crystallization.Rise with the concentration of dampening, the temperature of solution is maintained to decline.In addition, by reactor 140 The low temperature that temperature is kept prevents the oxidation of HMD.Also it can provide blanket of nitrogen protection to prevent the oxidation of HMD.

As shown in figure 3, in one embodiment, reactor 140 has internal coil 152, refrigerant can be passed through to institute It states in internal coil 152, the temperature of reactor is adjusted between 60 DEG C and 110 DEG C.In another embodiment, it reacts Device 140 can have the collet (not shown) containing refrigerant.Internal coil can adjust temperature by the heat of recycling reaction generation.

In addition to temperature controller, reactor 140 can also have the atmospheric vent hole with vent condenser, to maintain to react Atmospheric pressure in device 140.Pressure controller can have internally and/or externally pressure sensor.

In one embodiment, sampling line 153 also may be present, for measure nylon salt pH value and/or salt it is dense Degree.Sampling line 153 can be in fluid communication with recirculation circuit 141, and preferably receive the fixed stream flowed through, with to greatest extent Reduce influence of the flowing to analyzer in ground.On the one hand, sampling line 153 can be withdrawn from recirculation circuit 141 less than 1% Nylon salt solution, more preferably less than 0.5%.One or more analyzers 154 may be present in sampling line 153.In some realities It applies in mode, sampling line 153 may include filter (not shown).In another embodiment, sampling line 153 can wrap Containing suitable heating or cooling device, such as heat exchanger, to control the temperature of sample flow.Similarly, sampling line 153 may include Water-filling pipeline (not shown), adjusts concentration for adding water to sample flow.If water is added into sample flow, water can be with It is deionized water.Calculate the water fed by sampling line 153, to maintain target salinity, and can also adjust water other into Material.Analyzer 154 may include in-line analyzer, be used for real-time measurement.According to the type of sampling, tested part can be through By 155 Returning reactor 140 of pipeline or discharge.Sampling line 153 can be returned by recirculation circuit 141.In addition, probe tube Line 153 is back to reactor 140 in different positions.

Continuous stirred tank reactor 140 keeps liquid level 156, and the liquid level 156 is at least 50% and expires, for example, at least 60% It is full.Select liquid level so that it is enough to be submerged in the blade in CSTR, to prevent the foaming of nylon salt solution.Gas can be passed through Port 157 introduces nitrogen or other inert gases to above-mentioned 156 upper space of liquid level.

Agitating shaft 158 can have one or more impellers 159, as agitating paddle, hurricane band, anchor, Corkscrews, propeller and/ Or turbine.It is preferred that aial flow impeller, for mixing AA and HMD, because these impellers tend to prevent solid particles sediment anti- Answer the bottom of device 140.In other embodiments, impeller can be the radial turbine of flat sword, and the radial turbine has and circle Multiple blades of plate surrounding equidistant interval.There can be the impeller between 2 and 10 in entire agitating shaft 158, for example, at 2 And between 4.Blade 160 on impeller 159 can be straight, is curved, is recessed, is convex, is angled or inclined.Blade 160 quantity can change between 2 and 20, for example, changing between 2 and 10.If desired, blade 160 can be with With stabilizer (not shown) or scraper (not shown)

In an illustrative embodiment, agitating shaft can be three pitches (triple-pitch) turbine assembly. In such component, agitating shaft 159 includes at least one upper angled blade turbomachine (not shown) and at least one Lower angled blades turbine (not shown).In the turbine assembly of three pitches, the inclined surface of upper angled blade turbomachine is excellent Choosing and the inclined surface of lower angled blades turbine are offset.

Also more blender axis with different types of impeller can be used, such as spiral and anchor.Alternatively, it is also possible to use side Agitating shaft is filled, especially those sides with marine propeller fill agitating shaft.

By external motors 165 drive agitating shaft 158, can with the revolving speed mixing liquid between 50 and 500rpm, for example, Revolving speed between 50 and 300rpm.Agitating shaft 158 can removably be installed to the motor drive shaft on connector 167 166.The speed of movement can be different, but under normal circumstances, the speed should be enough to keep the whole surface region of solid particle with Liquid phase contact, it is ensured that available interface zone is maximized, to be used for solid-liquid mass transfer.

Reactor 140 can also include one or more baffle plates 168, for mixing and preventing the formation in dead zone.Baffling The quantity of plate 168 can change between 2 and 20, for example, between 2 and 10, and on the periphery of reactor 140 It is spaced evenly.Baffle plate 168 may be mounted at the inner wall of reactor 140.In general, using vertical baffling plate 168, but It is that curved baffle plate can also be used.Baffle plate 168 may extend above the liquid level 156 in reactor 140.

In one embodiment, reactor 140 includes gas vent, for making a return journey removing exhaust gas through pipeline 135；One recycling Tower 131, for condensable HMD to be back to reactor 140.Water 132 can be transported to recovery tower 131 and in recovery tower 131 Tower bottom 133 recycle.With minimum-rate come the efficiency that is passed through water to keep recovery tower 131, and calculate by recovery tower 131 into The water of material to keep target salinity, and adjusts the charging of other water.Emptying gas 134 can be condensed with recycle-water and monomer Exhaust gas can be returned through pipeline 133.Non-condensable gas, including nitrogen and air can be used as waste gas stream 135 and be removed.Work as recycling When tower 131 is a vent condenser, recovery tower 131 can be used to recycle exhaust gas and remove uncondensable gas.

Although showing an illustrative continuous stirred tank reactor, other acceptable continuously stir also can be used Mix kettle reactor.

Nylon salt solution storage

As shown in figure 3, being transported to storage tank 195 as nylon salt solution is formed, wherein nylon salt solution can be kept Until polymerization reaction needs.In some embodiments, storage tank 195 may include recirculation circuit 193, molten to recycle nylon salt Liquid.It can be used internal spray mixer 194 to keep the circulation in storage tank 195.In one embodiment, internal spray is mixed Clutch 194 can be located between the bottom 0.3 and 1.5 meter apart from storage tank 195, preferably between 0.5 and 1 meter.In addition, some In embodiment, at least part in nylon salt solution can be returned to reactor 140, to prevent production line from freezing and/or When system perturbations or when required target ph and/or target salinity change, nylon salt solution is corrected.Can also by it is any not The nylon salt solution used returns to storage tank 195 from the polymerization 200.

Holding vessel 195 can be constructed by resistant material, such as austenitic stainless steel, such as 304,304L, 316 and 316L or other suitable resistant materials are economically feasible flat to provide one between equipment life and fund cost Weighing apparatus.Storage tank 195 may include one or more storage tanks, this depends on the volume of storage tank size and the nylon salt solution for needing to store. In some embodiments, nylon salt solution is stored at least two storage tanks, for example, at least three storage tanks, at least four A storage tank or at least five storage tank.Storage tank 195 may remain at a temperature of the freezing point of solution or more, such as at 60 DEG C and 110 Temperature between DEG C.For having the nylon salt solution of the salinity between 60 weight % and 65 weight %, temperature is positively retained at Between 100 DEG C and 110 DEG C.Interior heater 196 may be present in storage tank.In addition, recirculation circuit can have one or more add Hot device 197, for providing heat for storage tank.For example, storage tank can have the appearance of the nylon salt solution of the inventory of receiving up to 5 days Amount, more preferably up to 3 days inventories.Storage tank can be maintained in nitrogen atmosphere under the pressure of atmospheric pressure or a little higher than atmospheric pressure.

In some embodiments, before entering storage tank 195, it may filter that nylon salt solution to remove impurity.It can lead to At least one filter 190 is crossed to filter nylon salt solution, for example, at least two filters or at least three filters.Filtering Device 190 may be configured to serial or parallel connection.Suitable filter may include membrane filter, and the membrane filter includes poly- third Alkene, cellulose, cotton and/or glass fibre.In some embodiments, filter can have the aperture between 1 to 20 microns Size, for example, between 2 and 10 microns.Filter is also possible to ultrafilter, Microfiltration Unit, nanometer filtration filter, or living Property carbon filter.

Compensate HMD

In as noted before, the HMD of the equivalent needed for nylon salt of at least three positions by formation is with different parts It introduces, to form nylon salt solution.It adds first part and forms PBA solution.In addition, the portion for being added to the HMD of container can be fixed The feed rate divided, dissolves AA powder to provide the HMD of necessary amount.Second and Part III are added in CSTR to be formed Nylon salt solution.In order to use a continuous stirred tank reactor, and uniform nylon salt solution is formed, once nylon salt Solution is discharged into conduit from reactor, and subsequently enters storage tank, then no longer adds HMD.HMD quilt in the form of compensating HMD It is introduced into the recirculation circuit of container, continuous stirred tank reactor and continuous stirred tank reactor.In order to use list A continuous stirred tank reactor, and uniform nylon salt solution is formed, once nylon salt solution is discharged into from reactor 140 Conduit 144, and subsequently enter storage tank 195, then no longer add HMD.As shown in figure 3, can by include at crosspoint 142 via The compensation HMD of pipeline 107 carrys out the variance control of further fine goal standard (such as target ph).Compensating HMD is usually to add The smallest a part of the HMD entered, and be used as the fine tuning to the pH of nylon salt solution and control, due to being fed compared to main HMD, make Have with lesser valve to the higher control of the minor change of fluid.The feed rate or flow velocity for adjusting main HMD are not intended to control The preferred method of the pH value of nylon salt solution processed, because of the time difference between the adjusting of main HMD and the measurement of pH value.In addition, because It is the least part for the HMD being added in CSTR for compensation HMD, compensation HMD allows the pH for more accurately adjusting nylon salt solution Value, and pH analyzer can provide nearprompt feedback.Compensation HMD is added in the upstream of pH value measurement, is mended with reducing to measure to be added Repay the delay of the influence of the pH value of HMD.When adjust compensate HMD when, the also feed rate of adjustable water, to control in the nylon salt The concentration of solid in solution.Such adjusting can be set by controller and the refractometer on sampling line 153 can be passed through Monitor such adjusting, as described herein.

Into before conduit 144, compensation HMD107 can be combined with nylon salt solution.If not theoretical constraint, Think that compensating HMD107 can be reacted with remaining free adipic acid any in nylon salt solution.In addition, as described above, can The pH value of nylon salt solution is adjusted using compensation HMD107 is added.

In one embodiment, the present invention relates to the PBA solution 306 that metering enters continuous stirred tank reactor 140；Point The aqueous solution including the first part of HMD104 ' and water 103 ' continuous stirred tank reactor 140 is not introduced into, to form nylon salt Solution；And the second part of HMD is introduced, such as the compensation HMD of nylon salt solution is arrived by pipeline 107.It can be by HMD104's ' First part and water 103 ' are combined to form aqueous HMD solution feed.Compensation HMD107 can be added to again at crosspoint 142 In nylon salt solution in circulation loop 141.Compensation HMD107 is continuously fed to be recirculated back to such feed rate In road 141, the feed rate makes the flow for compensating HMD107 be by the medium stream of valve, such as 20% to 60% 40% To 50%, or about 50%.Medium stream refers to the continuous flowing for keeping passing through valve, out of hand to prevent.

In order to realize that low variational target ph, this method include providing AA powder 102 using loss in weight feeder 110 Constant feed rate, to form PBA solution 306；And the feed rate of HMD and water are adjusted in response to technology controlling and process.Have Benefit, can realize high throughput rate by continuous processing.When changing salt throughput rate, as AA feed rate is discrete Variation in section proportionally adjusts HMD feed rate.The feed rate that reactor 140 can be fed by changing HMD Or as compensation HMD and the HMD that feeds adjusts the feed rate of HMD.In one preferred embodiment, for given Salt throughput rate, the feed rate of adjustable compensation HMD107, and the feed rate of HMD104 ' and/or the aqueous HMD are molten The feed rate of liquid charging can be constant.In another embodiment, the feed rate for compensating HMD107 can be set It is set to constant rate, and if desired, the feed rate of adjustable HMD104 ' and/or the aqueous HMD solution feed Feed rate, to realize target ph and/or salinity.In other embodiments, adjustable HMD104 ' and compensation The feed rate of the feed rate of both HMD107 and/or the aqueous HMD solution feed, to realize target ph and/or salt Concentration.

Compensation HMD107 can have and the identical source HMD HMD104 '.HMD104 ' may include in nylon salt solution Between the 80% and 99% of total HMD, for example, between 90% and 99%.Compensating HMD107 may include in nylon salt solution Between the 1 and 20% of total HMD, for example, between 1% and 10%.HMD104 ' can be adjusted according to target pH and target salinity With the ratio of compensation HMD107.As discussed herein, HMD104 ' can be set by the feed rate model of total HMD and mended Repay the ratio of HMD107.

Compensation HMD can have source identical with the HMD of container and continuous stirred tank reactor is used for.It can be with pure HMD HMD is provided, for example, comprising at least HMD of 99.5 weight %, for example, 100% HMD and anhydrous；Or 80 weights can be contained The aqueous solution of the HMD between % and 99.5 weight % is measured to provide HMD.It will compensation in the form of the aqueous solution of pure HMD or HMD HMD107 is passed through nylon salt solution.When compensating HMD is the aqueous solution of HMD, compensation HMD107 aqueous solution may include between 50 weights The HMD between % and 99 weight % is measured, for example, HMD between 60 weight % and 95 weight % or between 70 weight % and 90 weights Measure the HMD between %.As HMD104 ' aqueous solution, water can be adjusted based on the required salinity of the source HMD and nylon salt solution Amount.Advantageously, the HMD concentration of compensation HMD107 is 90 weight % to 100 weight %, to improve the shadow of the control to pH value It rings, while minimizing the influence of compensation HMD107 in salinity control.

Compensation HMD107 is added in the nylon salt solution of recirculation circuit, and the recirculation circuit is in pump 149 and takes The upstream of sample pipeline 153.After the second part of addition HMD107, analyzer 154 can be used to measure in sampling line 153 The pH value of nylon salt solution in recirculation circuit 141.This allows adjusting pH value with the feed rate of compensation HMD107 There is a small delay between pH measurement.There is no additional AA to be added to recirculation circuit 141.Other than compensating HMD107, There is no HMD to be added to recirculation circuit 141.By the upstream of the second part addition pH measurement of HMD107, to allow to include The pH value of the second part of HMD107 measures.

Different from the prior art shown in U.S. Patent Publication 2010/0168375 and United States Patent (USP) US4233234, in pH Compensation HMD is not added after measurement.HMD is added after pH measurement, can be generated when measuring influence of the HMD being added to pH value One big delay, because before measuring, the HMD of addition must pass through reactor.Therefore, HMD is added in this way Can undershoot or overshoot target ph, cause to run with making these process inefficiencies by continuous pursuing of goal pH value.Have Sharp ground, the present invention increase compensation HMD in the upstream that pH value measures, so that the influence of compensation HMD leads to seldom delay simultaneously Avoid the problem that undershoot or overshoot target ph.In addition, because maintaining valve with medium stream, the present invention can continuously charge satisfaction HMD107。

Process control

As described herein, in the continuous process of the salting liquid (such as nylon salt solution) for producing polyamide, In the method for the prior art, the goal standard (including pH and salinity) in nylon salt solution may changing property.It may be by not The predictable variability at least partly causing this goal standard with the AA powder feed rate fluctuated.It is this can not be pre- The property surveyed and fluctuation keep control process difficult because must constantly monitor before storing and adjust the downstream of initial reactor this A process.Therefore, the single reactor of continuous operation cannot effectively final result be unpredictable and the AA powder feed speed of fluctuation Rate.In the past, in order to solve this unpredictability and fluctuation, using multiple reactors, mixer and more reaction-ure feeding positions, Especially for adding the reaction-ure feeding position of HMD, to generate the nylon salt solution of goal standard.Use of the invention one Continuous stirred tank reactor eliminates the ability for adjusting nylon salt solution in a plurality of reactors.However, can be by leveling AA powder Last feed variation realizes improved technology controlling and process, i.e., by using loss in weight feeder to form PBA solution and using should PBA solution forms nylon salt solution as the source of AA, and the variation of AA powder feed rate is made to be less than ± 5%.On the one hand, this hair Bright to use the feedforward control (feed forward control) based on model, under conditions of being with or without feedback, realization has The nylon salt solution of target ph and salinity.

Feedforward control

Before starting the continuation method for manufacturing nylon salt solution, the throughput rate based on required nylon salt solution come Prepare reaction model.Based on the throughput rate, AA powder feed rate is set, then sets target ph and target salinity. Then the feed rate of HMD and the feed rate of water are calculated, through stoichiometry to realize target ph and target salinity.HMD Feed rate include the HMD to form PBA solution, the main HMD into reactor, and compensation HMD.The feed rate of water includes logical Enter all water sources of container and reactor 140.It is understood that target pH reflects the target molar ratio of AA ratio HMD.Into In the embodiment of one step, can additional feature in a model, include but are not limited to reaction temperature and reaction pressure.The mould Type is the feedforward control for feed rate is arranged, for HMD and/or water to be fed into container and continuously stir autoclave reaction Device.In some embodiments, which can be used for the solution feed of setting PBA to the feedforward control of continuous agitator tank reactor System.

In some respects, which is the model prepared by inputting the feed rate of AA powder, the AA powder Feed rate is provided by loss in weight feeder of the present invention.The model also can be set the HMD for being fed into container into Rate is expected, to realize required eutectic mixture.For given throughput rate, the feed rate of AA should be constant.Such as this Described in invention, loss in weight feeder may include discrete control, to generate low variational AA powder feed rate.Can it is continuous, It is semicontinuous, or with discrete time interval (as every 5 minutes, every 30 minutes or per hour) by from loss in weight feeder The feed rate of AA powder is supplied to model.In other respects, due to being the low variability of AA powder feed rate, once it sets The feed rate of AA powder, the model can set the feed rate of HMD and the feed rate of water.Set by model these into Expect rate to realize target ph and target salinity.

The model can be dynamically, and can be adjusted by the feedback signal from online or offline analyzer Section.Such as, if it is desired to change throughput rate, pH or salinity, adjustable model.Model adjusting can be stored in controller Memory in, the controller such as programmable logic controller (PLC) controller, dcs (DCS) control Device or proportional-integral-differential (PID) controller.In one embodiment, having the PID controller of feedback signal can be used for Solve the error of model calculating and flow measurement.

Due to using volume feeder to be unable to the feed rate of Accurate Prediction AA powder, can not implement before with feedforward Control forms the low variational nylon salt solution of relative target specification in itself.This is at least partially because by volume feeder Use the variability of caused AA powder feed rate.Because of the variability of AA powder feed, model cannot be generated to control AA With the ratio of HMD.As a result compared with feedforward control, feedback control is can be used in these conventional methods, thus it requires frequently adjust or For batch procedures.However, when measured based on weight AA powder to have dispersing head container when, feedforward control is enough continuously Generate the low variational nylon salt solution of relative target specification.

Therefore, in one embodiment, a kind of for controlling nylon salt solution production the purpose of the present invention is being related to Method comprising: the model of a target feed rate for AA powder is generated, to generate PBA solution, and obtained nylon Salt has target salinity and/or target ph.As noted before, target salinity can be selected from 50 weight % and 65 weight % Between range value, for example, the value of the range between 60 weight % and 65 weight %.Target pH can be selected from 7.200 Hes The value of range between 7.900, for example, the value of the range between 7.400 and 7.700.The method may further include: point HMD is not introduced by container with the first feed rate, container is introduced the water into the second feed rate, wherein described first and/or Two feed rates are based on the model for PBA solution.The method can also further comprise: individually with third feed rate PBA solution is introduced into continuous stirred tank reactor, wherein the third feed rate is based on the model for nylon salt solution. The method can also further comprise: individually introducing HMD and water with the 4th feed rate and the 5th feed rate connect respectively Continuous stirred tank, wherein the 4th and/or the 5th feed rate is based on the target feed rate for AA powder Model.HMD and PBA solution reaction forms nylon salt solution, and the nylon salt solution then can be from continuous stirred tank reactor In continuously withdraw from and be directly entered storage tank.The nylon salt solution then can be stored, the polymerization reaction for future.Regardless of selection Target salinity or pH value, the variability of the practical specification relative target specification of nylon salt solution is low, such as less than 0.53% Variability, for example, less than the 0.4%, variability less than 0.3% or less than 0.1%.

In order to which process control schemes according to the present invention are further illustrated, Fig. 4 shows a flow chart.For letter Change, various pumps, recirculation circuit and heater are excluded in Fig. 4.Fig. 4 shows several flowmeters, such as Coriolis mass flow Meter (coriolis mass flow meters), volumetric flowmeter, electromagnetic flowmeter and turbine flowmeter, for measuring Flow through the logistics of system.In some embodiments, flowmeter can also measure temperature and/or density.It can continuous or periodicly By the output valve input controller 113 of flowmeter.It is preferred that there are at least one flowmeters for the upstream of each flowmeter valve.In some realities It applies in mode, flowmeter and flowmeter valve can be whole, and come together to provide in encapsulation package.Although illustrating only one Multiple controllers may be present in controller in some embodiments.As shown in figure 4, AA powder is sent to weightlessness via pipeline 102 Formula feeder 110, to generate the AA powder feed 139 of metering.Controller 113 send signal 211 to rotation spiral 123.It is described Signal can be wireless signal.Using model, the model of the feed rate that is used to feedover is storable in controller 113, before described Feedback feed rate is the feedforward feed rate for HMD and water.As described above, loss in weight feeder 110 adjusts the change of AA powder The property changed, to provide the AA powder feed 139 with the metering low relative to target feed rate variability.For example, weight-loss type into The feedback loop from weight measurement subsystem 121 can be used to adjust the speed of rotation spiral 123 in glassware 110.

Controller 113 sends flowmeter valve 214 for feed-forward signal 213 to adjust the flow that water 103 flows into container 302. Similarly, controller 113 sends flowmeter valve 216 for feed-forward signal 215 to adjust the flow that HMD104 flows into container 302. By these feed-forward signals of model specification, to realize the molar ratio and/or target salinity of target ph, AA ratio HMD.HMD and Water can be combined into HMD aqueous solution and be fed into container 302.

In another embodiment, the PBA that controller 113 by feed-forward signal 227 sends flowmeter valve 228 to adjust Solution 306 enters the feed rate of continuous stirred tank reactor 140.When not using storage tank 184, it is necessary to set flowmeter valve 228 to container 302 throughput rate, will limit inventory in this way.By these feed-forward signals of model specification, with realize target ph and Target salinity.Since feed-forward signal 213 and 215 be used to HMD and water being passed through container 302, it is not necessary that take it is any The measurement of line or offline PBA solution 306.In order to provide sufficient amount HMD and water to form required nylon salt solution, DCS control Device 113 processed can send feed-forward signal respectively, the charging speed based on the PBA solution 306 for being fed into continuous stirred tank reactor 140 HMD and water are transported to continuous stirred tank reactor 140 by rate.Feed-forward signal 229 can the target based on the solution 306 of PBA into Expect rate, and feed-forward signal 229 can control flowmeter valve 230 providing the HMD104 ' of aequum to continuous stirred tank Reactor 140.In addition, also sending flowmeter valve 218 for feed-forward signal 217 to adjust compensation HMD107 and flow into recirculation circuit 141 flow.The model can determine HMD by HMD104 be sent into container 302 in HMD, main HMD104 ' and compensate The relative quantity of HMD107.Controller 113 can also send feed-forward signal 231,231 controllable flow meter valve 232 of feed-forward signal with By the supply of compensation water 103 ' to continuous stirred tank reactor 140.Compensation water 103 ' can be directly fed to continuous stirred tank reaction Device 140 is supplied by exhaust line to continuous stirred tank reactor 140.Feed-forward signal 217 and feed-forward signal 229 are adjusted, with Guarantee the output medium stream that there is the flowmeter valve 217 of flow direction compensation HMD107.In one embodiment, model can establish Flow rate is to ensure to compensate the constant flow that HMD107 is maintained, i.e. intermediate flow, and the flow rate is by feed-forward signal 217 It is sent to flowmeter valve 218.

Secondary process control

In addition to using the feedforward control based on modeling, as shown in figure 4, process control may include as the second process control Feedback signal, to realize target ph and target salinity.These feedback signals can be from flowmeter and in-line analyzer The measurement data obtained in 154, flowmeter and in-line analyzer 154 are used to adjust the charging in HMD and water, preferably adjust compensation The charging of HMD and water.In-line analyzer 154 may include pH probe, refractometer and combinations thereof.PH probe and refractometer can connect Or it is in parallel.

As shown in figure 4, this method uses in-line analyzer 154, such as online pH meter 154 to measure in recirculation circuit The pH value of nylon salt solution in 141 is to generate feedback signal.For the ease of the on-line measurement of the pH value of nylon solution, by nylon Salting liquid is continuously passed through recirculation circuit 141 and sampling from taking-up in reactor and by least part in nylon salt solution In pipeline 153.Recirculation circuit 141 may include flowmeter (not shown) and flowmeter valve.In another embodiment, it then follows Loop back path 141 may include pressure controller (not shown), to control the flow of nylon salt solution.Preferably, nylon salt solution Stream by recirculation circuit 141 is constant.Sampling line 153 include for pH value determination tool (such as pH meter) and/ Or the tool (such as refractometer) for salinity measurement.In one embodiment, under conditions of reactor, without any Under conditions of dilution or cooling, the pH value of at least one portion of nylon salt solution is measured.Then by the nylon salt solution At least part is direct or is back in reactor 140 through vent condenser 131.When at least part of the nylon salt solution When returning to reactor through vent condenser 131, nylon salt solution can replace the water being passed through in vent condenser.Sampling line 153 can also include the cooler (not shown) and temperature sensor (not shown) of cooling nylon salt solution, the temperature sensing Temperature of the device measurement before pH measurement.In some embodiments, before pH measurement, nylon salt solution is cooled to target temperature Degree.The target temperature can be the target of the range between 5 DEG C lower than the nylon salt solution of its outflow reactor 140 and 10 DEG C Temperature.The temperature can relative target temperature be less than ± 1 DEG C in the range of change, be, for example, less than ± 0.5 DEG C.Temperature may be present Sensor (not shown) come monitor pH value measurement upstream nylon salt solution temperature.

Output 226 is then supplied to controller 113 by online pH meter 154.The output 226 measures online pH meter 154 PH value is sent to controller 113.Online pH meter 154 is used to determine the variability of the pH value of the nylon salt solution in continuous process. In other words, online pH meter 154 can measure the pH value different from target ph, but when the pH of measurement changes, controller 113 can adjust monomer feed.In a preferred embodiment, the pH value of nylon salt solution becomes in the range of being less than ± 0.04 Change, be, for example, less than ± 0.03 or be less than ± 0.015.Due to the drift of the measured value of online pH meter, online pH meter is for measuring The variability of pH value, rather than measure absolute pH value.This is at least partially due to feedforward control, the feedforward control allow to set Fixed target ph.It determines whether pH value changes by using online pH meter, can detect variation in process of production.It uses Two-stage control, the variation of pH may cause the corresponding adjusting of at least one feed rate, pass through signal wire 217 and 229 point It is not sent to flowmeter valve 218 and 230.On the one hand, it when PBA solution 306 is passed through in reactor 140 with constant, preferably adjusts It is fed into the HMD of reactor 140 and the feed rate of water, rather than adjusts the container 302 that these are fed into production PBA solution Feed rate.It is adjusted to provide a willing pH, valve 218 is sent signal to by route 217 to adjust compensation HMD107.The amount of the adjusting compensation HMD107 made is determined by the corresponding change of the HMD104 ' by flowmeter valve 230.By In will affect PBA solution, therefore the HMD104 for being fed into container 302 is not adjusted preferably.This adjusting is sensitive, and is not had once There is the variation of display pH, the feed rate set by feedforward control should be able to be restored to.These to compensation HMD107 adjusting The salinity of nylon salt solution can also be influenced.Water can be adjusted by the signal 231 by flowmeter valve 232 to control this salt The variation of concentration.

Because the process for forming nylon salt solution be it is continuous, can be in real time (for example, continuously) or close The pH measurement data of online pH meter 154 is obtained in real time.In some embodiments, every progress pH measurement in 60 minutes, for example, Every 45 minutes, every 30 minutes, every 15 minutes or every 5 minutes.PH meter can have the precision within ± 0.05, such as exist Precision within ± 0.02.

According to the required adjusting based on feedback, can also be independently adjusted with Two-stage control into container by model 302 and both reactors 140 HMD and water.Particularly advantageously when leading to long-term compensation there are the trend of a pH value The adjusting of HMD107.

In addition to the feedback from online pH meter 154, each flowmeter 214 ', 215 ', 218 ', 228 ', 230 ' and/or 232 ' Information or mass flowrate can be provided respectively via signal 213 ', 215 ', 218 ', 227 ', 229 ' and/or 231 ' to controller 113. The information from flowmeter can be used to maintain whole throughput rate.

The art methods of the pH value of the nylon salt solution using pH probe measurement have been disclosed.See United States Patent (USP) 4233234 and U.S. Patent Publication 2010/0168375.However, each measurement nylon salt of these art methods is molten Then the pH value of liquid adds additional diamines and/or acid to adjust pH value.The effect of additional diamines and/or acid is not known simultaneously, Until additional diamines and/or acid-mixed enter in reactor, and further take out for measuring.This method causes " to pursue " pH value, and Generate insensitive process control, possible undershoot or overshoot target ph.

In the present invention, as shown in Figure 4, preferably compensation HMD107 is supplied to the upstream of online pH meter.To compensation HMD in HMD107 is followed again in conjunction with the nylon salt solution in reactor recirculation circuit, and by reactor 140 The pH value of nylon salt solution is measured before ring.

It is controlled using the Secondary process of online measurement in lab

As described above, the pH measurement data from Two-stage control process not necessarily reflects target ph, but for calculating The variation of pH value.In order to improve the sensitivity of pH measurement, Secondary process control can also relate to measure under the control of laboratory The pH value of nylon salt solution.Not theoretical constraint, due to increasing under conditions of reduced concentration and temperature close to inflection point The sensitivity of the pH measurement at place, the pH value for measuring nylon salt solution in laboratory conditions improve the precision of measurement.This can permit Perhaps the small pH variation that detection may be not taken care at reaction conditions.For purposes of the present invention, the condition in laboratory is Refer to the nylon salt solution sample that measures at a temperature of between 15 DEG C and 40 DEG C, for example, between 20 DEG C and 35 DEG C or 25 DEG C, ±0.2℃.The nylon salt solution sample measured in laboratory conditions can have the salinity between lower 8% and 12%, such as 9.5%.Carry out this pH survey in laboratory conditions online by diluting and cooling down the nylon salt solution in sampling line 153 Amount.

As shown in figure 4, in laboratory conditions, for the ease of the pH value of on-line measurement nylon solution, by nylon salt solution It is continuously taken out from reactor, and by least part in nylon salt solution, for example, the nylon salt less than 1% is molten Liquid draws as arrived recirculation circuit 141 and sampling line 153.Sampling line 153 includes carrying out pH value measurement in laboratory conditions Tool.Sampling line 153 can also include cooler (not shown) to cool down nylon salt solution.In other embodiments, The cooler can be omitted.The temperature and concentration of nylon salt solution in sampling line 153 can be by adding via pipeline 220 Add water to adjust.The water is the sub-fraction of total water feed rate, and total water feed rate is calculated by model 's.The amount and temperature that water is added sufficiently achieve temperature required for the diluted nylon salt solution sample for pH measurement and strong Degree.It may also include further cooling dilute sample.In laboratory conditions, at least part of pH of nylon salt solution is obtained Value, then as described herein by least part Returning reactor 140 of nylon salt solution.Then online pH meter 154 provides defeated 226 give controller 113 out.

As described above, online pH meter 154 is used to measure the variability of the pH value of nylon salt solution.In preferred embodiment In, the variation of the pH value of nylon salt solution is less than ± 0.04, for example, being less than ± 0.03 or less than ± 0.015.Similar to reacting Under the conditions of pH value measurement, due to the drift of online pH meter measured value, measured using online pH meter in laboratory conditions The variation of pH value, rather than measure target ph.This allows to set target ph at least partially due to feedforward control It sets.It determines whether the pH value changes by using online pH meter, can detecte variation in process of production.It is similar to Secondary process control can adjust feed rate by transmitting a signal to route 217 and 229, then to flowmeter valve 218 and 230. These adjustings may also influence the salinity of nylon salt solution.Water is adjusted by being sent to the signal 231 of flowmeter valve 232 And control the variation of this salinity.

Because the process in the nylon salt solution of the formation be it is continuous, online pH meter 154 can be in real time (for example, even Continuous ground) or the pH measurement data that obtains of near real-time ground.In some embodiments, every 60 minutes, for example, every 45 minutes, Every 30 minutes, every 15 minutes or every 5 minutes, to obtain pH measurement data.PH measuring tool should have ± 0.05 essence Degree, such as ± 0.03 or ± 0.01 precision.

Three-stage process control

As shown in figure 4, although can help to reduce the variation of nylon salt solution specification using feedforward control and feedback signal Property, but still further analysis can be used, it is especially for use in the offline pH analysis carried out under laboratory condition, to detect nylon The uniformity of salting liquid.This off-line procedure control in laboratory conditions is referred to as three-stage process control, may include pH And/or salinity measurement.In one embodiment, can off-line measurement nylon salt solution in laboratory conditions pH value, with Determine whether to realize target ph.Offline pH value measurement can also detect the deviation that any instrument problems or needs are adjusted. In another embodiment, the pH value of the nylon salt solution of off-line measurement can also be used to adjustment and be connected to stream in laboratory conditions The signal wire 217 and 229 of meter valve 218 and 230.In laboratory conditions, offline pH measurement can have in ± 0.01 range The ability of interior pH value determination.

As described herein, laboratory condition refers to measuring nylon salt solution at a temperature of between 15 DEG C and 40 DEG C Sample, such as at a temperature of between 20 DEG C and 35 DEG C or at 25 DEG C ± 0.2 DEG C, for example, ± 0.2 DEG C.It surveys in laboratory conditions The nylon salt solution sample obtained can have the concentration between 8% and 12%, for example, 9.5% concentration.In order to reach this Temperature and concentration, dilutable water and the cooling nylon salt solution sample taken out from recirculation circuit.Temperature bath can be used cold Diluted nylon salt solution sample.Can take out sample based on demand, for example, every 4 to 6 hours, daily or weekly.It is being The case where failure of uniting, sample can be more frequently taken out, for example, per hour.Under normal circumstances, off-line analysis instrument can by with To solve the instrumental bias of in-line analyzer.For example, in-line analyzer may report that pH value is if target ph is 7.500 7.400 and off-line analysis instrument report pH value be then 7.500, this shows the instrumental bias of online pH analyzer.On the one hand, whenever Off-line measurement has been carried out, then has come to be biased in line analysis instrument automatically using exponentially weighted moving average.In some respects, offline point The output of analyzer is used to correct for any deviation or drift of in-line analyzer.In other aspects, in-line analyzer is not corrected, but It is supervised by off-line analysis instrument to survey drift or deviation.In this respect, the variation of pH is determined by in-line analyzer, for example, Except preset acceptable changeability.

In another embodiment, off-line analysis instrument can be used for measuring the target salinity of nylon salt solution.Offline salt The measurement of concentration also can detecte the problem of any instrument or adjustable deviation.When using multiple refractometers, each refraction Instrument may independently have deviation.

Nylon polymerization

Nylon salt solution described in the invention can be passed through polymerization process 200 to form polyamide, especially nylon 6,6. Nylon salt solution directly can be sent into polymerization process 200 from continuous stirred tank reactor 140, or can first deposited nylon salt solution Storage is then fed into polymerization process 200, as shown in Figure 5 in storage tank 195.

Nylon salt solution of the invention has uniform pH value, can improve the performance of polyamide polymerization process.Nylon The uniform pH of salting liquid provides reliable raw material to produce a variety of polyamide products.Which greatly improves polymeric articles Reliability.Under normal circumstances, polymerization process includes evaporating water from the nylon salt solution nylon salt solution is concentrated；With And it polymerize the nylon salt of concentration by being condensed to form polyamide product.One or more evaporator 202 can be used.It can be The evaporation for completing water in vacuum or under stress, to remove at least 75% water in the nylon salt solution, more preferably in nylon At least 95% water in salting liquid.Dense nylon salt 203 may include the water between 0 and 20 weight %.It can be in batch or continuous process In be condensed.Depending on desired final polymer product, additional AA and/or HMD can be added to polymer reactor In 204.In some embodiments, additive can be integrated in polyamide product.

For purposes of the present invention, carbochain of the suitable polyamide product between amide group at least 85% can be with It is aliphatic.

When being transported to evaporator 202 from storage tank 195, keeps the temperature of nylon salt solution more than its fusing point, in this way may be used To prevent pipeline scaling.In some embodiments, can be used for keeping the temperature from the steam that evaporator 202 captures.At it In its embodiment, the cooling water of heating also can be used.

Polymerization reaction can be in single stage reactor or multistage condensation reactor 204 in carry out.Pipeline can be passed through 205 are added additional monomer, AA or HMD, but preferred HMD, to generate different nylon products 208.In one embodiment, A part of the solution 308 of PBA can be introduced reactor 204, to generate different nylon products 208.Reactor 204 may include For mixing the blender of nylon salt.Reactor 204 can also have collet to adjust temperature, and the collet uses heat transfer medium.Instead It answers the condensation reaction in device 204 that can carry out in an inert atmosphere, and nitrogen can be added in reactor 204.According to rise The temperature of beginning dicarboxylic acids and diamines, polymerization reaction can change, but usually more than the fusion temperature of nylon salt, and more preferably exist More than fusion temperature at least 10 DEG C.E.g., including the nylon salt of adipic acid hexamethylene diamine salt has the model between 165 DEG C and 190 DEG C Enclose interior fusion temperature.Therefore, condensation reaction can be carried out under the temperature of reactor between 165 DEG C and 350 DEG C, such as At a temperature of between 190 DEG C and 300 DEG C.Condensation reaction can carry out under conditions of normal pressure or pressurization.Nylon product 208 is with freedom The solid product form of flowing is removed from reactor.

The water generated in condensation reaction can be removed in the form of steam stream reactor ventilation line 209.Institute State steam stream can for the condensation that is escaped together with moisture and gaseous monomer, such as diamines can return it in reactor.

Subsequent processing, such as extrusion, spinning, stretching or stretcher strain can be carried out, to produce polyamide product.Polyamide produces Product can be selected from being made of nylon 4,6, nylon 6,6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 11 and nylon 12 Group.In addition, polyamide product can be copolymer, such as 6/ nylon 6,6 of nylon.

Method of the invention is described below by way of non-limiting embodiment.

Embodiment 1

Pass through machine from container bag unloading, the unloading of liner container bag, the unloading of liner box container or hopper compartment debarkation stop Tool (i.e. screw, drag chain) or pneumatic (i.e. pressure air, evacuated air or closed loop nitrogen (closed loop nitrogen)) conveying AA powder is delivered to supply container by system.

Supply container leads to according to requiring for AA powder to be delivered to weight-loss type (loss-in-weight, L-I-W) feeder It crosses based on the low level of selected L-I-W hopper and high-order PLC and controls.Supply container passes through screw conveyor or rotary feeding Device measures AA powder with enough loading rates, to allow to carry out L-I-W feeder hopper under maximum time interval Filling, the maximum time interval are equivalent to one from the high-order minimum L-I-W efflux time to low level of L-I-W container Half, preferably smaller than half, to receive the feedback of the feed rate of L-I-W feeder at least 67% time.

The L-I-W feeder system PLC adjusts L-I-W feeder screw revolving speed, and to keep charging rate, the screw rod turns Speed is to survey from the received feed rate target of distribution control system (DSC) from the L-I-W feeder hopper weighing sensor ?.

As shown in Fig. 6, by the variability of the feed rate of the adipic acid of loss in weight feeder, have in continuous feed It is less than ± 5% feed-rate variation in 48 hours.As shown in fig. 7, the variation of feed rate can be less than within 48 hours ± 3%.As shown in figure 8, the variability of charging rate can be less than ± 1% in 18 hours.Using the weight-loss type for adipic acid into Glassware, by eliminating as using volume feeder caused by interference to adipic acid feed rate, the charging being improved The variational performance of rate.

Embodiment 2

Adipic acid (PBA) solution of partial equilibrium is prepared as follows.

The AA powder feed is supplied in container from L-I-W feeder, in this case, the container be include point Dissipate the continuous stirred tank reactor of head.Dispersing head stirs the reaction-ure mixture of AA powder and dilute HMD solution continuously to generate The PBA solution of deionized water with 43.3% AA, 14.2% HMD and 42.5%.The container also has an outside Direct insertion mixer for the grinding of additional reaction mixture, and is recycled back into disperser CSTR.Partial equilibrium oneself Solid concentration of the diacid solution with 57.5 weight % and the free AA containing 25.4 weight %.

The set-point DCS of AA powder feed rate for L-I-W is by being based on entering continuous stirred tank reactor The PBA solution feed rate of (continuous stirred tank reactor, CSTR) and/or the target stored for PBA The DCS model of inventory level determines.

Dilute HMD solution is prepared as follows.The HMD storage recycling head that HMD solution (98%) is controlled from pressure is provided to appearance Device.Using coriolis mass flowmeters measurement and be input to DCS, DCS adjusts the HMD feed stream for entering PBA container Flow velocity, accurately to control the ratio of AA and HMD in reaction-ure mixture.For the target value of 63% salinity, hold in PBA 41.2% HMD charge of the HMD charge that the technique requires is added in device.Greater than 45 DEG C at a temperature of be passed through HMD Solution.

Deionized water is mixed with HMD solution, to form dilute HMD solution and be passed through in PBA container.From pressure control go from Sub- water supply head provides water.Using coriolis mass flowmeters measurement and be input to DCS, DCS, which is adjusted, enters container The flow velocity of the feed stream of deionized water, accurately to control the water concentration of AA and HMD in reaction-ure mixture.For 63% Salinity target value, PBA solution feed are the smallest 56.75% solids (43.25% water), to allow to minimize for anti- Answer the vent condenser of device and the injection of the deionized water for concentration offsets adjustment.Between 20 DEG C and 30 DEG C close to room temperature Under be passed through water.

PBA container has external direct insertion mixer also to be used for mixed reactant mixture and return dispersion recycling It is back in PBA container, and for dispersion to be passed through storage tank.

When pressure head discharge capacity is limited in lower than dispersion to be directly discharged to pressure needed for subsequent tank, the straight cutting Formula mixer is the direct insertion displacer assisted by pump or be provided in the recirculation circuit of the storage tank as guidance stream. It is used the phegma of storage tank as the kinetic current of direct insertion displacer.

Direct insertionly using the heat exchanger of the storage container recirculation circuit, arrived to promote the temperature of PBA solution Minimum 50 DEG C, preferably 55 DEG C and 60 DEG C, to keep PBA as homogeneous phase solution, without suspended crystal.Dispersion from container and storage tank The interflow of body recycles, with the side of the simple T shape pipe with force (forcing) pump charging or the direct insertion displacer with container charging Formula is mounted on the upstream of recirculation circuit heat exchanger, to guarantee that mixed flow is real now into needed for before storage container Minimum temperature.

The recirculation rate of the storage recirculation flow of the PBA is controlled, to provide enough kinetic current rates to re-circulation line The mixing displacer of property displacer and storage tank.The tank mixing displacer is located at between pot bottom 0.2 and 1.5 meter, for example, excellent It is selected as between 0.5 and 1 meter, to ensure being thoroughly mixed for content in container and dispersion.Enter recirculation pipe by adjusting The steam flow of the heat exchanger of line adjusts tank temperature between 50 DEG C and 60 DEG C, preferably between 55 DEG C and 60 DEG C.

Embodiment 3

Nylon salt solution is prepared to realize the target salinity of 63% concentration and 7.500 target ph.Use embodiment 2 Source of the PBA solution of preparation as the adipic acid of nylon salt solution.

DCS provides entrance using based on the throughput rate of polymer reactor and the DCS model of target salt inventory level The target feed rate of PBA solution in salt CSTR, and the target is adjusted in settable time interval.Pass through Ke Liao The means of sharp mass flowmenter measure PBA solution feed rate and control the PBA solution feed rate, reach DSC In target.

The charging of the balance HMD of the feed rate based on target PBA is controlled using feedforward Ratio control circuit in dcs Rate.Adjusting the output that DCS balances the set-point of HMD ratio flow controller to keep compensating HMD valve is medium range, with true Valve is protected continuously in control range, for 63% salt target, the charge for balancing HMD is usually the process that is filled with The 48.8% to 56.8% of HMD amount, and when in conjunction with PBA solution, the about charge of the HMD of 90-98%.

By the continuous pH value determination of extra pH meter, the pH meter the recirculation pump offer by reactor, screening and In the sample recirculation circuit of temperature and flow rates controlled.Selected by DCS of the DCS using the pairs of online pH measurement continuously compared PH input value compensates the feed rate of HMD to adjust, to maintain pH value in DCS target set-point.For 63% salt target, mend The charge for repaying HMD be about be filled with it is described during total HMD 2-10%.

According to the set point for adjusting pH value controller based on the algorithm of statistics, the algorithm using discrete interval is derived from The pH value of the sample in the downstream of reactor is analyzed；Function of the algorithm as pH value is in 9.5% concentration and 25 DEG C of temperature To realize acid/amine balance peak response under conditions of degree；Or by continuously inputting pH value from in-line analyzer, connect The concentration of the product to 9.5% of the reactor of continuous dilution/decision and at a temperature of 25 DEG C or serial dilution/decision is from subsequent The concentration of the product to 9.5% of storage container (if it is preferred that) and 25 DEG C at a temperature of.

HMD will be supplemented and be injected into the suction inlet that recirculation circuit pumps in main reactor, to realize the most fast sound to pH meter Between seasonable, and guarantee to adjust reactor product within the shortest time to target value.HMD is mixed using pump and reactor salt produces Object, to ensure that pH meter and densimeter have homogeneous phase solution, to measure pH and concentration respectively for it.

The concentration of reactor is continuously measured by extra refractometer, the refractometer is in the recycling by reactor Pump provide equally screen and in the sample recirculation circuit of temperature and flow rates controlled.DCS uses the company of online measurement of concetration Continue the concentration input value for the DCS selection compared in pairs to adjust the feed rate of compensation deionized water, to maintain concentration in dcs Target set point.For 63% salt target, the charge of compensation water be filled with it is described during total Water 1% to 5%, Preferably from about 3%.

Reactor product is continuously delivered to storage tank by the Liquid level tool of CSTR, wherein the reactor product Further mixing is to be provided to polymeric device.This transmission includes the candle filter shell that at least one is arranged in juxtaposition, institute Stating candle filter shell is for the up to 34.5kPa under the maximum instantaneous salting liquid transmission rate when entering storage The original net pressure drop design of (5psig).When using synthetic fibers thickness (depth) or fold membrane filter, filter core removal rate is The smallest 10 μm of absolute value, or when using Wound-rotor type cotton fiber filter core, filter core removal rate is minimum 1 μm of nominal value. The selection of device is filtered based on the selection of the value of minimum 110 DEG C of operation temperature.

Saline solution is continuously recycled by salt storage tank, it is preferable to use tank mixing displacer, the tank mixing discharge Device is located at between tank bottom 0.5 and 1 meter, so that tank content is more rapidly overturn to maximize mixing efficiency.

For 63% salinity, the adjusting of the steam flow of the heat exchanger by entering recirculation line adjusts salt The temperature of storage tank is between 100 DEG C to 105 DEG C.Salt in the storage tank has 7.500 uniform pH value, relative target PH is less than ± 0.0135.

Comparative example A

Mixture is prepared from the embodiment 1 of United States Patent (USP) US6995233.By the mass concentration of water be equivalent to 10% it is dense Aqueous HMD solution and AA powder be continuously introduced into the first stirred reactor, obtain the AA monomer and 19 weights with 81 weight % Measure the mixture of the weight ratio of the diamine monomer of %.The mixture can contain a small amount of water, such as mix relative to AA/HMD The water of the weight of object about 7%.The temperature of mixture is maintained at about 126 DEG C, to prevent from crystallizing.

Comparative example B

The model and method of embodiment 1-3 are followed, the difference is that, no HMD is transported in container.From storage tank Partial equilibrium solution of adipic acid includes the adipic acid of 49.7 weight % and the water of 50.3 weight %, and preferably must be held in 85 DEG C In temperature, to prevent from solidifying.

Comparative example C

The model and method of embodiment 1-3 are followed, the difference is that, no water is transported in container.Only by AA and HMD It is impossible for being fed into container, because cannot dissolve AA in the absence of water in container, which will have high viscous It spends and could only handle at very high temperatures.

Comparative example D

The model and method of embodiment 1-3 are followed, the difference is that, L-I-W feeder is replaced using volume feeder By AA powder feed to container.The variation of the pH value relative target pH value of nylon salt solution is greater than 0.1pH unit.PH value compared with Difference control can lead to significant higher freezing point, this will need higher processing temperature, to prevent the risk of crystallization.

Comparative example E

The model and method of embodiment 1-3 are followed, the difference is that, no compensation water is fed into reactor.Buddhist nun The salinity of imperial salting liquid increases to 63.707% from 63%, and this requires storage temperature with higher before the polymerization, examples Such as 3.5 DEG C to 4 DEG C.Raised temperature for storage will be close to the boiling temperature of nylon salt solution under normal pressure.In order to more Increased salinity is mended, the concentration of partial equilibrium solution of adipic acid is reduced, because without compensation water, and realize uniform concentration To be more difficult.

Although the present invention has been described in detail, the skill of modification within the spirit and scope of the present invention for this field Art personnel will be apparent.All publications discussed above and bibliography are incorporated by reference in the present invention. Additionally it should be to understand, the various spies of the part and record of each aspect of the present invention and each embodiment in the present invention Sign can be combined in whole or in part or be exchanged.In the description of above-mentioned each embodiment, as those skilled in the art can be with Understand, those implementation embodiments for referring to another embodiment can be combined suitably with other embodiment.Moreover, It will be appreciated by persons skilled in the art that the description of front is only example way, it is not intended to limit the invention.

Claims

1. a kind of for producing the continuation method of nylon salt solution comprising:

A) partial equilibrium acid solution is formed, comprising the following steps:

1) by weight, dicarboxylic acid powder is controlled by measuring the dicarboxylic acid powder from loss in weight feeder to feed pipe Dicarboxylic acid powder is delivered to the container including dispersing head by feed-rate variation rate, the feed pipe；

2) the first feed streams of diamines are included into the dicarboxyl between 32 weight % and 46 weight % into container with formation The dispersion of the water between diamines and 39 weight % and 57 weight % between acid, 11 weight % and 15 weight %；And

3) dispersion is stored with liquid at a temperature of between 50 DEG C and 60 DEG C；And

B) nylon salt solution for realizing target salinity and target ph, including following step are formed from partial equilibrium acid solution It is rapid:

1) withdraw from a part of partial equilibrium acid solution from the dispersion of storage, and by a part of the partial equilibrium acid solution with Second feed stream of diamines is concomitantly introduced into single continuous stirred tank reactor to form nylon salt solution；And

2) nylon salt solution is continuously withdrawn from from single continuous stirred tank reactor, and be passed directly into storage tank, wherein nylon The salinity relative target salinity of salting liquid changes in the range of within ± 0.5%, and the pH value of nylon salt solution is opposite Target ph changes in the range of within ± 0.04,

Wherein, the diacid is adipic acid, and the diamines is hexamethylene diamine.

2. the method according to claim 1, wherein the feed-rate variation rate of the dicarboxylic acid powder ± Within 5%.

3. the method according to claim 1, wherein the container further comprises having one or more straight cuttings The recirculation circuit of formula mixer.

4. the method according to claim 1, wherein the nylon salt solution is not introduced container to form dispersion Body.

5. the method according to claim 1, wherein the partial equilibrium acid solution does not form slurry.

6. the method according to claim 1, wherein the target ph is between 7.200 and 7.900 Value in range.

7. the method according to claim 1, wherein the target salinity is selected from 50 weight % and 65 weights Measure the value between %.

8. the method according to claim 1, wherein the first feed stream of the diamines include 15 weight % and Diamines and 70 weight % between 30 weight % to 85 weight % water.

9. the method according to claim 1, wherein the second feed stream of the diamines include 20 weight % and Diamines and 5 weight % between 95 weight % to 80 weight % water.

10. the method according to claim 1, wherein setting the first feed stream and the institute of the diamines as follows State the feed rate of the second feed stream of diamines:

A) model is generated, comprising:

I. setting is used for the throughput rate of nylon salt solution；

Ii. the dicarboxylic acid powder feed rate of the throughput rate is realized in setting；And

Iii. setting is used for the target ph of nylon salt solution；And

B) the charging speed of the feed rate of the first feed stream of diamines and the second feed stream of diamines is determined using model Rate is to realize target ph.

11. according to the method described in claim 10, it is characterized in that, by one or more pumps and analyzer circuit Upstream addition compensates diamines feed stream to adjust the pH value of the nylon salt solution, and the nylon salt in analyzer circuit The pH value of solution.

12. according to the method for claim 11, which is characterized in that the method further includes moving from analyzer circuit Sample carries out offline pH value measurement out.

13. according to the method for claim 11, which is characterized in that by the way that the content in analyzer circuit is diluted to 8% To 12% concentration, and the temperature that the content in analyzer circuit is cooled to 15 DEG C to 40 DEG C is come in analyzer circuit PH value measurement data.

14. according to the method for claim 13, which is characterized in that the pH value measurement data is different from target ph.

15. the method that one kind is used to form nylon 6,6, including,

According to claim 1, method described in any one of -14 produces nylon salt solution,

The nylon salt solution is evaporated to form concentration stream, and

It polymerize the concentration stream in the second reactor to form polyamide product.