CN104130403B

CN104130403B - For producing the metering method of the dicarboxylic acid powder of nylon salt solution

Info

Publication number: CN104130403B
Application number: CN201410143891.6A
Authority: CN
Inventors: 罗伯特·J·韦尔奇; 利恩·曼斯特; 保罗·诺米科斯
Original assignee: Invista Textiles UK Ltd
Current assignee: Invista Textiles UK Ltd
Priority date: 2013-05-01
Filing date: 2014-04-10
Publication date: 2018-05-29
Anticipated expiration: 2034-04-10
Also published as: TW201444792A; CN104130403A; WO2014179057A1

Abstract

Disclosed is a kind of nylon salt solution preparation method including loss in weight feeder and continuous stirred tank reactor.The nylon salt solution is prepared by the way that dicarboxylic acid monomer and diamine monomer are fed single continuous stirred tank reactor.Enter the dicarboxylic acids of reactor from loss in weight feeder based on weight metering.Nylon salt solution is continuously produced, and it has the low variability from target ph and/or target concentration of salt solution.Nylon salt solution is directly transferred to holding vessel after continuous stirred tank reactor outflow, is added in without further monomer, pH value is adjusted or salting liquid is adjusted.

Description

For producing the metering method of the dicarboxylic acid powder of nylon salt solution

Cross reference to related applications

This application claims the priority for enjoying in the U. S. application 61/818041 submitted on May 1st, 2013, this application Full content and disclose it is incorporated herein.

Technical field

Preparation the present invention relates to nylon salt solution more particularly to the nylon salt using single continuous stirred tank reactor are molten The preparation of liquid.

Background technology

Polyamide be generally used for weaving, clothes, packaging, tire enhancing, carpet, automobile molding portion engineering thermoplastic Property plastics, electronic equipment, sports equipment and various commercial Applications.Nylon is a kind of high performance material, can be used for requirement tool In terms of standby excellent durability, the plastics of heat resistance and toughness and fiber.The fatty polyamide for being referred to as nylon can be by two It is prepared by the salting liquid of carboxylic acid and diamines.It is heated after the salting liquid is evaporated so that it polymerize.In such production method One challenge is ensuring that in last polyamide dicarboxylic acids has consistent mol balance with diamines.Pass through oneself for example, working as Diacid（AA）And hexamethylene diamine（HMD）Nylon-6 is produced, when 6, inconsistent mol balance can disadvantageously result in molecular weight reduction, and Influence the stainability of nylon.Mol balance is realized by using interval salt technique, but batch technology is not suitable for greatly Technical scale metaplasia is produced.In addition, mol balance can also be realized by multiple reactors in a continuous mode, it is every in the production of salt A reactor has individual diamines to supply.

US2130947 describes one kind such as formula H₂NCH₂RCH₂NH₂Shown diamines and formula HOOCCH₂R’CH₂Shown in COOH Dicarboxylic acids salting liquid, wherein, R and R ' are free from olefinic and the undersaturated bivalent hydrocarbon radical of acetylene series, and R has at least two carbon The chain length of atom.The pH value of salting liquid is measured, and determines inflection point.Then the salting liquid is fed in reactor, it is poly- to be formed Amide.

US2012/0046439 describes the preparation method of a kind of diacid for being used to prepare polyamide and diamines salting liquid.It should Method includes mixing at least two diacid and at least one diamines, and wherein the weight concentration of salt is 40~70%, the method bag Contain：In the first step, the aqueous solution of diacid and diamines is prepared using a kind of diacid and a kind of diamines, wherein diacid and diamines rubs You than less than 1 and in second step, adjusting the molar ratio of diacid and diamines to 0.9-1.1, and pass through another acid of addition and Optionally additional water and/or diamines correct the weight concentration of salt.

US2010/0168375 describes the salting liquid of diamines and diacid, and especially hexamethylene diamine adipate is dense Solution, can be as the initial material of production polyamide, especially production PA66.The solution can be by the first step by two Amine and diacid mixing（Wherein the weight concentration of salt is 50-80%）, to provide the aqueous solution of diacid and diamines（Wherein diacid/diamine Molar ratio be more than 1.1）And the molar ratio of diacid/diamine is adjusted to 0.9-1.1 by adding in diamines in second step, It is preferred that 0.99-1.01, and optionally add in water thereto and prepared with correcting the weight concentration of salt.

US4233234 describes a kind of alkane of the continuous alkane dicarboxylic acid and 6-12 carbon atoms for preparing 6-12 carbon atom The method of the aqueous solution of the salt of diamines, by by specific alkane dicarboxylic acid and specific alkane diamine salt to be prepared water It reacts to prepare in solution.The aqueous solution of salt is recycled to the first mixing from the first mixed zone by transmission range and the second mixed zone Area, liquid alkane diamines and alkane dicarboxylic acid's aqueous solution introduce between the first mixed zone and the second mixed zone.Introduce less than etc. The alkane diamine of equivalent, the liquid alkane diamines of surplus add in after the second mixed zone, and the aqueous solution of the salt is with its shape Into speed removed from the first mixed zone.

US6995233, US6169162, US5674794 and US3893811 disclose polymer reactor.

Although having attempted modified technique to obtain target component, such as suitable pH value, mol balance and/or nylon salt solution In salinity, but still there is challenges.Especially dicarboxylic acids is more particularly adipic acid, is with variable particle The powder of size, so that bulk density change is very big.Another variable will be introduced using dicarboxylic acid powder, so that The uniformity of target component, such as the uniformity of pH and/or salinity are difficult to realize in a continuous process.For dicarboxylic acid powder Volumetric feeder exacerbate this difficulty.Difficulty in view of the uniformity for realizing target component in a continuous process, it is existing There is technology to be dissolved first before dicarboxylic acid powder is imported continuous stirred tank reactor or use series reaction device And combine volumetric feeder to adjust pH value and salinity.Dissolved powders increase equipment using additional reactor Amount, cost of investment and cost of energy.

The content of the invention

In the first embodiment, the present invention relates to a kind of for producing the continuation method of nylon salt solution, including：a） By controlling dicarboxylic acid powder feed rate based on dicarboxylic acid powder of the weight metering from loss in weight feeder to feed pipe Variability, dicarboxylic acid powder is transferred in single continuous stirred tank reactor by the feed pipe；b）By the water comprising diamines Solution is individually introduced into the single continuous stirred tank reactor to form nylon salt solution；And c）By nylon salt solution from It is continuously taken out and is introduced directly into holding vessel in single continuous stirred tank reactor, wherein the pH value of the nylon salt solution deviates Target ph is less than ± 0.04 or ± 0.03 and changes, and the nylon salt solution includes the salinity of 50-65wt.%.Dicarboxylic acids The feed rate variability of powder is smaller than ± 5%.Target ph may be selected from the range of 7.200-7.900.Step b）It can be further It is introduced continuously into including diamines charging will be supplemented in the recirculation circuit of the single continuous stirred tank reactor.The aqueous solution can be The position of the feed points of neighbouring feed pipe introduces, and is fed to partly to dissolve in single continuous stirred tank reactor Dicarboxylic acid powder.The aqueous solution can include the diamines of 20-55wt.%.The aqueous solution can include the water of 45-80wt.%.The nylon salt Solution can include the salinity of 60-65wt.%.The single continuous stirred tank reactor is positively retained under inert atmosphere.This method can Further comprise purifying nylon salt solution using one or more filters before holding vessel.Single continuous stirred tank reaction Device is positively retained at 60-110 DEG C of temperature and normal pressure.The dicarboxylic acids can be adipic acid, and the diamines can be hexa-methylene two Amine, the salting liquid include hexamethylene diamine adipate.

In second embodiment, the present invention relates to a kind of polymerization of nylon salt solution, including：a）Based on weight Measure dicarboxylic acid powder from loss in weight feeder to feed pipe, the feed pipe by dicarboxylic acid powder with low variability into Material rate is transferred in first reactor；b）Aqueous solution comprising diamines is individually introduced into first reactor to form nylon Salting liquid；c）The nylon salt solution is evaporated to form concentration logistics；And d）The concentration logistics is gathered in the second reactor It closes to form polyamide products.The nylon salt solution can have target ph.Target ph may be selected from the scope between 7.2-7.9 It is interior.The pH value of nylon salt solution can deviate target ph ± 0.05 and change.The first reactor can be that continuous stirred tank is anti- Answer device.The feed rate of the low variability, which can have, deviates the variability that target feed rate is less than ± 5%.The aqueous solution can connect The position of the feed points of nearly feed pipe introduces, partly to dissolve the dicarboxylic acids powder that will be fed in first reactor End.The aqueous solution can be introduced in the position of the feed points 0.3-1m apart from feed pipe.Continuous stirred tank reactor may include list A reactor.The aqueous solution can include 20-55wt.%, the diamines of such as 30-45wt.%.Nylon salt solution can include 60- The salinity of 65wt.%.First reactor is positively retained under inert atmosphere.This method can further comprise making before holding vessel Purify nylon salt solution with one or more filters.First reactor is positively retained at 60-110 DEG C of temperature and normal pressure. In one embodiment, the dicarboxylic acids is adipic acid, and the diamines is hexamethylene diamine.Dicarboxylic acids/diamine salts can be Hexamethylene diamine adipate.The polyamide products can be nylon 6,6.

In the third embodiment, the present invention relates to a kind of for producing the continuation method of nylon salt solution, including a） Adipic acid powder based on weight metering from loss in weight feeder to feed pipe, the feed pipe shift adipic acid powder Enter in continuous stirred tank reactor；b）Aqueous solution comprising hexamethylene diamine is individually introduced into the continuous stirred tank reaction To form nylon salt solution in device；c）Nylon salt solution from the continuous stirred tank reactor is continuously taken out and is directly led Enter in holding vessel, wherein the pH value of the nylon salt solution has target ph, and the salinity comprising 50-65wt.%；And d）The feed rate variability of adipic acid powder is controlled, so as to which target ph variation is less than ± 0.05.

In the 4th embodiment, the present invention relates to a kind of for producing the process unit of nylon salt solution, including：Bag Containing hopper, feed pipe and loss in weight feeder for connecting the pipe of the hopper and the feed pipe, wherein described Hopper is used to control the external weights of supply stage and charging stage measurement subsystem and at least one use including at least one In the lower openings that dicarboxylic acid powder is distributed in the charging stage, wherein at least one lower openings are located on feed pipe Side；Wherein described feed pipe receives dicarboxylic acid powder and is shifted dicarboxylic acid powder by least one spiral propeller Pass through outlet；And be connected to feed pipe outlet first entrance and for introducing diamines, water or their mixing One or more second entrances of object are to produce the continuous stirred tank reactor of nylon salt solution, wherein the continuous stirred tank is anti- Device is answered to include single reactor.The first entrance is close to one or more of second entrances.The feed pipe can be installed To the pipe.The system can further comprise with adding the supply storehouse of valve, and the supply storehouse is in the supply stage by dicarboxylic acids powder End is delivered in hopper.The system can further comprise for dicarboxylic acid powder being transferred to the transmission in hopper from supply storehouse Band.The system can further comprise for dicarboxylic acid powder being loaded onto the pneumatic transport system in supply storehouse.The supply storehouse There can be the top edge being located above system ground elevation at less than 15 meters.The hopper, which can have, is located at system ground elevation Top is less than the top edge at 15 meters.The feed pipe section further includes one or more for introducing nitrogen gas into dicarboxyl Gas port in sour powder.The continuous stirred tank reactor can have at least one recirculation circuit.The pipe can include revolution Formula dispenser.The hopper can have with passing through the equivalent volume of the discharge capacity of the dicarboxylic acids of the pipe at least 15 minutes. The supply stage can be less than the 20% of total cycle time.The feed pipe can towards continuous stirred tank reactor downwards into 0-45 ° of angle.The system can further comprise the engine for driving at least one rotating screw pusher.The rotation Screw impeller can be the rotating screw pusher of fixed rate.The rotating screw pusher can be the rotation of variable bit rate Turn screw impeller.Nylon salt solution can include the salinity of 50-65wt.%, and include dicarboxylic acids/bis- with target ph Amine salt, wherein the target ph is selected between 7.2-7.9.

In the 5th specific embodiment, the present invention relates to a kind of for producing the process unit of nylon salt solution, bag It includes：Comprising hopper, feed pipe and loss in weight feeder for connecting the pipe of the hopper and the feed pipe, wherein The hopper including at least one is used to that the external weights of supply stage and charging stage to be controlled to measure subsystem and at least one A lower openings for the distribution adipic acid powder in the charging stage, wherein at least one lower openings are located at feed pipe Above road；Wherein the feed pipe receives adipic acid powder and by least one spiral propeller by adipic acid powder It is displaced through outlet；And be connected to feed pipe outlet first entrance and for introducing hexamethylene diamine, water And/or one or more second entrances of their mixture to be to produce the continuous stirred tank reactor of nylon salt solution, wherein The continuous stirred tank reactor includes single reactor.

Description of the drawings

Below by infinite attached drawing, the invention will be further described, wherein：

Fig. 1 is the production technology schematic diagram of the nylon salt solution of corresponding one embodiment of the invention；

Fig. 2 is the loss in weight feeder used in nylon salt solution is produced of corresponding one embodiment of the invention Schematic diagram；

Fig. 3 is the single continuous stirred tank used in nylon salt solution is produced of corresponding one embodiment of the invention The schematic diagram of reactor；

Fig. 4 is the single continuous stirred tank used in nylon salt solution is produced of corresponding one embodiment of the invention The sectional view of reactor；

Fig. 5 is the schematic diagram of the nylon salt solution production technology of corresponding one embodiment of the invention；

Fig. 6 is the signal that the process for nylon salt solution production technology of corresponding one embodiment of the invention controls Figure；

Fig. 7 is the process with Two-stage control for nylon salt solution technique of corresponding one embodiment of the invention The schematic diagram of control；

Fig. 8 is the process with three class control for nylon salt solution technique of corresponding one embodiment of the invention The schematic diagram of control；

Fig. 9 is the having in laboratory conditions for nylon salt solution technique of corresponding one embodiment of the invention The schematic diagram for the process control that the on-line pH value of progress measures；

Figure 10 is the nylon-6 of corresponding one embodiment of the invention, the schematic diagram of 6 production technologies；

Figure 11-13 is the charging for the adipic acid from loss in weight feeder for showing corresponding one embodiment of the invention The figure of the variability of rate.

Specific embodiment mode

Term used herein is not intended to limit the present invention merely for the purpose of description particular embodiment.On unless Hereinafter clearly show other situation, singulative as used herein "one" and "the" also include plural form. It is also understood that illustrate 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 " comprising ", "comprising", " having ", the term and its variant of " containing " or " being related to " should widely understand, and And comprising listed main body and equivalent, there is unlisted other main body.In addition, when by transitional phrases " bag 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 with 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, action and all functionalities in claim Rapid equivalent includes any knot for carrying out perform function in combination with the other component specifically stated in claim Structure, material or action.The present invention specification for introduce and description purpose and provide, but be not exhaustive or will this Invention is restricted to disclosed form.On 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 of ordinary skill 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 causes 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 by the claims.

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

Introduction

The present invention relates to the methods of continuous production nylon salt solution, are entered including metering by loss in weight feeder and continuously stirred The dicarboxylic acid powder in kettle reactor, for example single continuous stirred tank reactor is mixed, in the continuous stirred tank reactor, for example Dicarboxylic acid powder is reacted with diamines and water in single continuous stirred tank reactor.The nylon salt solution can be used for forming nylon 6, 6.The process unit advantageously uses the loss in weight feeder combined with single continuous stirred tank reactor to form homogeneous Buddhist nun Imperial salting liquid.Due to the low feed rate variability of the dicarboxylic acid powder from loss in weight feeder, this method is to existing skill The improvement of art.The low feed rate variability to dissolve powder before feeding to reactor, is also not required to Additional continuous stirred tank reactor is wanted to obtain homogeneous nylon salt solution, such as homogeneous pH value and salinity, therefore phase Than in existing method, The method reduces equipment, energy cost and fund costs.

Be suitable for the invention dicarboxylic acids may be selected from by ethanedioic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, oneself two Acid, suberic acid, azelaic acid, decanedioic acid, heneicosanedioic acid, dodecanedioic acid, maleic acid, glutaconate, traumatic acid, Muconic acid, 1,2- or 1,3- cyclohexyls dicarboxylic acids, 1,2- or 1,3- phenylenediacetic acids, 1,2- or 1,3- cyclohexyls Oxalic acid, M-phthalic acid, terephthalic acid (TPA), 4,4 '-oxydibenzoic acid, 4,4- benzophenone bases dicarboxylic acids, 2,6- naphthalenes The group that dicarboxylic acids, p- tert-butyl isophthalic acids, 2,5- furan dicarboxylic acids and its mixture are formed.In a specific embodiment In, the dicarboxylic acid monomer includes at least 80% adipic acid, such as at least 95% adipic acid.

Adipic acid（AA）It is to prepare nylon-6,6 dicarboxylic acids most adapted to use in the form of a powder.It is commonly available Pure AA contains minimal amount of impurity.Typical impurity includes other acids less than 60ppm（Monoacid and relatively low binary Acid）, nitrogenous material, trace metal（Such as iron（Less than 2ppm）With other heavy metals（Less than 10ppm or less than 5ppm））, arsenic（It is few In 3ppm）And hydrocarbon ils（Less than 10ppm or less than 5ppm）.

Be suitable for the invention diamines be selected from by ethanoldiamine, trimethylene diamine, putrescine, cadaverine, hexamethylene diamine, 2- methyl-five methylene diamine, heptamethylene diamines, 2- methyl hexamethylene diamine, 3- methyl hexamethylene diamine, 2,2- bis- Methyl pentamethylene diamine, eight methylene diamines, 2,5- dimethyl hexamethylene diamine, nine methylene diamines, 2,2,4- and 2, 4,4- trimethyls-hexamethylene diamine, decamethylene diamine, 5- methylnonanes diamines, isophorone diamine, 11 methylene two It is amine, ten dimethylene diamines ,-eight methylene diamine of 2,2,7,7- tetramethyls, double（P- aminocyclohexyl）It is methane, double（Ammonia first Base）Norbornane, optionally by one or more C₁-C₄Alkyl-substituted C₂-C₁₆Aliphatic diamine, aliphatic poly ether diamine and Furans diamines, such as 2,5- are double（Aminomethyl）Furans and its mixture.The boiling point of selected diamines can be higher than dicarboxylic acids, and institute It is not preferably xylyene diamine to state diamines.In a specific embodiment, the diamine monomer includes at least 80% 6 methylene Base diamines, such as at least 95% hexamethylene diamine.Hexamethylene diamine（HMD）It is most commonly used to prepare nylon-6,6.HMD is about 40-42 DEG C of solidification, is usually added into water to reduce its fusion temperature, is easily processed it.Therefore, the HMD of concentrated solution form, such as dense The diamines spent for 80~100wt.% or 92~98wt.% is commercially available.

It is sometimes advantageous to add in other monomers for polyamide except being based solely on dicarboxylic acids and diamines.When addition Ratio is less than 20wt.%, when being such as less than 15wt.%, also can these monomers be added to nylon under the premise of not departing from the present invention In salting liquid.Such monomer may include monofunctional carboxylic acids, such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, benzoic acid, caproic acid, heptan Acid, octanoic acid, n-nonanoic acid, capric acid, hendecanoic acid, dodecanoic acid, tetradecanoic acid, tetradecenoic acid, palmitic acid, palmitoleic acid, 16 Carbon enoic acid（sapienic acid）, stearic acid, oleic acid, elaidic acid, octadecenoic acid, linoleic acid and erucic acid etc..Such monomer is also May include lactams, as α-beta-lactam, α-azetidinone, azetidinone, butyrolactam, δ-valerolactam, γ- Valerolactam and caprolactam etc..Such monomer further includes lactone, such as α-second lactone, α-propiolactone, beta-propiolactone, γ-fourth Lactone, δ-valerolactone, gamma-valerolactone and caprolactone etc..Such monomer may also include the alcohols of two functional groups, such as mono-vinyl second Glycol, DIETHYLENE GLYCOL, 1,2- propylene glycol, 1,3- propylene glycol, diallyl ethylene glycol, 1,2- butanediols, 1,3- fourths two Alcohol, 1,4- butanediols, 2,3- butanediols, 1,2- pentanediols, 1,5- pentanediols, Rutgers 612（etohexadiol）, p- terpanes- 3,8- glycol, 2- methyl -2,4-PD, 1,6-HD, 1,7- heptandiols and 1,8- ethohexadiols.High function can also be used Spend molecule, such as glycerine, trimethylolpropane and triethanolamine.Suitable hydroxylamine also alternative such as ethanolamine, diethyl Hydramine, 3- amino -1- propyl alcohol, 1- amino -2- propyl alcohol, 4- amino-n-butyl alcohol, 3- amino-n-butyl alcohol, 2- amino-n-butyl alcohol, 4- Amino -2- butanol, amylalcohol amine and hexanol amine etc..It is understood that it can also adopt without departing from the scope of the present invention The mixture of monomer described in any one.

Other additives are introduced into polymerization technique to be also advantageous sometimes.These additives may include heat stabilizer, such as Mantoquita, potassium iodide or any other antioxidant well known in the prior art.Such additives may also comprise polymerization catalyst, such as Metal oxide, acid compound, the metal salt of oxygen-containing phosphorous compound or other compounds well known in the prior art.It is such Additive is alternatively delustering agent and colorant, such as titanium dioxide, carbon black or other pigment, dyestuff and well known in the prior art Toner.Additive used may also comprise antifoaming agent, such as silica dispersions, silicone copolymers or known in the state of the art Other antifoaming agent.Lubricating auxiliary agent can also be used, such as zinc stearate, stearyl erucamide, stearyl alcohol, aluminium distearate, second Alkenyl bis-stearamides or other polymers lubricant well known in the prior art.It may also include nucleating agent in mixture, such as forge Silica or aluminium oxide processed, molybdenum disulfide, talcum powder, graphite, calcirm-fluoride, phenyl-phosphonite salt or well known in the prior art Other auxiliary agents.Also other typical additives known in the art can be added in into polymerization technique, such as fire retardant, plasticizer, are resisted Impact modifier and other kinds of filler.

In the following description, term adipic acid（AA）And hexamethylene diamine（HMD）For representing dicarboxylic acids and two Amine.However, the method is also used for other dicarboxylic acids mentioned above and other diamines.

The present invention readily obtains the nylon salt solution for including the AA/HMD salt with target ph.Especially, it is of the invention Target ph is obtained using the container fewer than traditional handicraft number, especially in single reactor, such as forms nylon salt wherein The single continuous stirred tank reactor of solution（CSTR）In obtain target ph.In a continuous process advantageously with single anti- Device is answered, the productivity higher than batch technology can be obtained.It is similar with obtained by continuous processing to obtain in batch technology Time quantum and equipment investment cost needed for productivity so that batch technology is unrealistic.The target ph can be this field Any pH value of technical staff's selection, and can be selected according to required final polymeric articles.It is not bound by theory, Target can be selected from the highest inflection point of pH curves, and it is optimal water to be in for the scope of expected polymeric articles It is flat.

In some illustrative embodiments, the target ph of nylon salt solution can be between 7.200~7.900 It is worth, the value between preferably 7.400~7.700.The variation of the actual pH of nylon salt solution and the target ph of nylon salt solution ± 0.04, more preferably less than ± 0.03, most preferably less than ± 0.015 can be less than.Thus, such as when target ph is 7.500, that The pH value of nylon salt solution is between 7.460~7.540, more preferably between 7.470~7.530.In this way, for example work as target Salinity is 60%, then the variability of the salinity of uniform nylon salt solution between 59.5%-60.5%, more preferable 59.9%~ Between 60.1%.In order to achieve the object of the present invention, the variability of pH value refers to the variation of mean rate in continuous operation.This variability is very It is small, less than ± 0.53%, more preferably less than ± 0.4%, obtain the nylon salt solution with homogeneous pH value.One kind is with low variability The uniform nylon salt solution for deviateing target ph is conducive to improve the reliability of polymerization technique, to produce uniform, high quality Polymeric articles.Nylon salt solution with homogeneous pH value also allows for feeding into polymerization technique stabilised quality.Institute Stating target ph can change according to production site.Under normal conditions, based on free and chemically combined AA and HMD, 25 DEG C and 9.5% salinity under 7.620 pH value that measures, generate with the nylon salt solution that AA/HMD molar ratios are 1.In order to It achieves the object of the present invention, molar ratio can be according to target ph 0.8:Change in the range of 1.2.It also anticipates with homogeneous pH value The molar ratio that taste nylon salt solution has corresponding low variability.

Except target ph, the present invention also can reach target salinity.Target salinity can be those skilled in the art The arbitrary salinity of selection, and can be made choice according to the considerations of required final polymeric articles and storage.Nylon salt is molten The water content of liquid can be between 35-50wt.%.The salinity of nylon salt solution can be 50~65wt.%, such as 60~65wt.%.Buddhist nun Imperial salting liquid such as can in fluid form preserve for 60~110 DEG C or 100-105 DEG C less than 110 DEG C under normal pressure.It is higher than The concentration of 65wt.% needs higher temperature and may need pressurization that nylon salt solution is made to maintain liquid, such as homogeneous liquid.Salt Concentration can influence storage temperature, usually can effectively store nylon salt solution at relatively low temperature and normal pressure.It is however, relatively low Salinity can adversely increase the energy expenditure for concentrating nylon salt solution before polymerization.

When continuously producing nylon salt solution according to the present invention, the salinity variability of nylon salt solution is preferably very low, Such as deviate target salinity less than ± 0.5%, less than ± 0.3%, less than ± 0.2% or less than ± 0.1%.In order to realize the present invention's Purpose, the variability of salinity refer to the variation of mean rate in continuous operation.Target salinity can change according to production site.

The temperature of nylon salt solution is controlled independently of the molar ratio of AA and HMD.Although mole in nylon salt solution Than the temperature that nylon salt solution is influenced with solid concentration, but technique relies on heat exchanger, coil pipe and/or jacket type CSTR from work Heat is removed in skill, so as to control the concentration of nylon salt solution.The temperature of nylon salt solution can be controlled and deviate required temperature Change in the range of less than ± 1 DEG C.The temperature of nylon salt solution can be selected in the boiling point less than nylon salt solution, but higher than Buddhist nun The crystallization temperature of imperial salting liquid.For example, the nylon salt solution boiling point under normal pressure that solid content is 63% is 108-110 DEG C.Cause This, by temperature control less than 110 DEG C, such as less than 108 DEG C, but is higher than crystallization temperature.

In order to realize the low variability of nylon salt, existing technical solution is concentrated on using in multiple reactors adjustment salting liquid AA：The concentration of HMD molar ratios and HMD.This variability for being concentrated to the bulk density for being at least partially due to AA powder and difference Flow behavior results in the intrinsic unpredictability of AA powder feeds.AA powder is fed instead when using volumetric feeder When answering device, the variability of the bulk density of AA powder is amplified.Due to the melting temperature of AA high, AA is usually in the form of a powder Supply, so as to increase the difficulty of processing AA.The average grain diameter of AA powder is usually at 75~500 microns, such as 100~300 microns Interior variation.This fine powder substantially has the surface area of bigger and more causes the particle contact of aggregation.Preferably, AA powder In contain the particle for being less than 75 microns less than 20%, such as less than 10%.Since AA powder is typically based in the form of a powder directly It is measured into the volume in reactor, thus the variation of powder size influences to feed dissipating for the AA powder in nylon salt reactor Packing and density.The variation of these bulk packages and density and then cause pH value and AA and HMD molar ratios in nylon salt solution Variation.In view of these variations, a series of salt reactor is provided in prior art.For example, see US2012/ 0046439 and US2010/0168375.This conventional method has used the measure of target component, and monomer is fed a series of anti- It answers in device.However, this technique needs substantial amounts of reactor, measurement and adjustment, so as to increase cost and limit productivity.Separately Outside, compared with continuous processing, this traditional method may be more suitable for batch technology.Finally, this traditional method cannot Enough pH value and/or salinity are predicted using model, thus need constantly to be adjusted so that nylon salt solution reaches target Parameter.

Use multiple reactors add AA and HMD have been set forth in the prior art with by AA powder feed nylon The effect of the related particle size of salt technique and Size Distribution.It has been found that based on weight rather than based on volume metering AA powder When last, the variability of AA feed rates can substantially reduce.In certain aspects, the feed rate of AA powder can deviate target AA powder Last feed rate changes less than ± 5%, is such as less than ± 3% or ± 1%.By this stable charging, disclosed technique allows to make With single reactor to form the nylon salt solution with target component, without multiple reactors of series connection.There is no AA's Stablize charging, being difficult to control nylon salt solution using the single reactor operated under high continuous production rate deviates target ph With the variation of target salinity, this is because adjustment monomer ability it is limited.Enable technology controlling and process with stable AA chargings The feed forward rate of HMD is enough utilized, and allows to adjustment supplement HMD to adjust pH value, to reach target ph.Advantageously, Desired embodiment is provided a kind of simpler than conventionally disclosed by reducing the number of the unit operation in technique Single design.Therefore, the step for thinking indispensable in the past is omitted in the technique of the disclosure.Which reduce floor space and investment Cost.Obtained nylon salt solution can further be polymerize and obtain required polyamide.

In the industrialized production of nylon salt solution, to realize acceptable production, continuous processing can be used to produce Buddhist nun Imperial salting liquid.Batch technique needs significantly greater container and reactor.Further, batch technology is difficult to obtain by smaller The continuous producing apparatus of type is with regard to obtainable productivity.In polymerization, originate in the nylon with homogeneous pH value and salinity Salting liquid is beneficial.Small variation can cause the product quality problems of polymerization, so as to which additional monitoring be needed to control and gathered Close the adjustment of technique.

Fig. 1 provides the technique general line of the production nylon salt solution of embodiment according to the present invention.As shown in Figure 1, Nylon salt solution technique 100 includes：Adipic acid is fed into loss in weight feeder 110 by pipeline 102, generates to introduce and continuously stir Mix the charging of the adipic acid after the metering in kettle reactor 140 139.In addition, the water by pipeline 103 and the HMD by pipeline 104 The aqueous solution of HMD is mixed to get in static mixer 105, is fed by pipeline 106 in continuous stirred tank reactor 140. Liquid containing nylon salt solution is withdrawn from by recirculation circuit 141 from reactor 140, is then return to reactor 140.At this Referred to herein as the additional HMD of supplement HMD, can be added in before analysis pH value or salinity by pipeline 107 in tie point 142 Into liquid to adjust the pH value of nylon salt.Nylon salt solution is withdrawn from from recirculation circuit 141 into pipeline in tie point 143 144.Nylon salt solution in pipeline 144 flows through filter 190 to remove impurity, is subsequently collected in holding vessel 195.General feelings Under condition, these impurity can include corrosion metal, and can include the impurity from monomer feed, such as AA powder 102.The nylon salt Solution can move into polymerization process 200 by pipeline 199.The nylon salt solution can be stored in holding vessel 195 until polymerization needs It will.In some embodiments, holding vessel 195 is moveable.

Nylon saline solution means

AA powder feeders based on weight

In a specific embodiment, as shown in Figure 2, AA powder 102 is fed into using loss in weight feeder 110 In continuous stirred tank reactor 140.Loss in weight feeder 110 measures AA powder 102 to generate with low variability feed rate AA powder feeds stream 139, it is contemplated that in fill process the density of AA powder 102 variation.As described above, AA powder 102 bulk density and flow behavior variation very greatly, so as to cause the imbalance for introducing molar ratio and generates nylon salt solution Inhomogenous pH value.Determine volume feeder or other types compared with the feed rate of the low variability that can not achieve AA powder Feeder for, the present invention is with advantage.Purpose to realize the present invention, the feed rate of the low variability of AA powder be In the range of target feed rate ± 5% of AA powder, such as in the range of ± 3%, in the range of ± 2% or ± 1% model In enclosing.In order to achieve the object of the present invention, the variability of feed rate refers to the variation of mean rate in continuous operation.Since AA is fed The low variability of rate, the feed rate of AA is stable and predictable, therefore can use single reactor, by customizing diamines and water Feed rate obtain target ph and/or target salinity.Since AA powder feed rates deviate target feed rate Other reactors are not required for mixing or adjusting in low variability.

In general, loss in weight feeder 110 loads hopper 111 in supplemental stages, and in the object of charging stage distribution hopper 111 Material.Preferably, enough at least 50% time, such as at least 67% time receives from weightlessness the supplement-charging stage Xun Huan The feedback signal of formula feeder 110.In a specific embodiment, supplemental stages account for total cycle time（Such as the charging stage and The total time of supplement）Amount can be less than 20%, such as be less than total cycle time 10% or 5% less than total cycle time.Supplemental stages Throughput rate is may depend on the time of total cycle stage.In the charging stage, the material in hopper 111 is distributed into feed pipe AA powder is transferred in continuous stirred tank reactor 140 by road 112 by pipeline 139.In addition, in supplemental stages, remain in AA in hopper 111 can also be assigned to feed pipe 112, and thus feed pipe 112 obtains the continuous supply of AA powder.Control Device 113 can be used for management and control loss in weight feeder 110.Controller 113 can be being capable of the input information that receives of output function response Dcs（DCS）Or programmable logic controller（PLC）.In a specific embodiment, can have more A controller is used for the different components of system.For example, PLC can be used for management and control supplemental stages, DCS can be used for by being set in DCS In targeted rate control pass through the feed rate of feed pipe 112.

As shown in Figure 2, AA powder 102 is fitted into supply storehouse 115 by transport system 114.Transport system 114 can be machinery Or pneumatic conveyer system, adipic acid is transferred out of from loose bags, lining bulk bag, liner box container or rail car terminal Come.Mechanical conveying system may include spiral or haulage chain.Pneumatic conveyer system can include closing pipeline, using forced air, The nitrogen of evacuated air or closed circuit send AA powder 102 to supply storehouse 115.In some embodiments, transport system 114 Mechanical function can be provided during storehouse 115 is supplied in loading to destroy the block of AA powder.Supply storehouse 115 can have cylinder Shape, trapezoidal, square or other suitable moulding have entrance 116 at the top of it.Moulding with the side with angle can help AA Powder 102 is flowed out from supply storehouse 115.System ground elevation 130 can be located above less than 20 meters by supplying the top edge in storehouse 115 Place, such as preferably shorter than 15m.System ground elevation 130 refers to the plane that the different device of production nylon salt solution is stopped, and logical Often define no monomer by plane.System ground elevation can be on the entrance of CSTR.Since supply storehouse 115 is opposite It is relatively low in the height of system ground elevation 130, it is necessary to which less energy drives transport system 114 and loading supply storehouse 115.

Supplying storehouse 115 also has lower valve 117, when lower valve 117 is closed, just defines and preserves the interior of AA powder 102 Portion's cavity.Lower valve 117 can be rotary feeder, feeding screw, rotational flow device or containing feeder and valve Unit equipment.When filling the internal cavity with AA powder 102, lower valve 117 remains off.In supplemental stages When, lower valve 117 can be opened, and AA powder 102 is sent to hopper 111 based on volume.When AA powder is sent to material by lower valve Struggle against 111 when, AA powder can be loaded into supply storehouse 115.Lower valve 117 may include one or more sealings of formation upon closing Rim strip.In one embodiment, AA powder 102 can pass through conveyer belt（It is not shown）Hopper 111 is sent to from supply storehouse 115. In other embodiments, AA powder can be transmitted by gravity by supplying storehouse 115.The loading for supplying storehouse 115 can be independently of hopper 111 Loading.

Hopper 111 can be more than by supplying the capacity in storehouse 115, and preferably described capacity is at least 2 times or at least 3 times of hopper 111 Greatly.The capacity in supply storehouse 115 should be enough the whole volume for supplementing hopper 111.What AA powder 102 preserved in supply storehouse 115 Time cycle, AA powder 102 can form agglomerate than being grown in hopper 111, and depending on humidity concentration.In supply storehouse 115 Bottom mechanical rotor or vibration can be used（It is not shown）Agglomerate is broken.

The top edge of hopper 111 can be located at 130 top of system ground elevation and be less than at 15m, as at preferably shorter than 12m.Material Bucket 111 can have cylindrical shape, trapezoidal, square or other suitable moulding, and have entrance 118 at the top of it.Preferably, expect The inner surface of bucket is inclined to prevent the bridging of AA powder.In a specific embodiment, the angle of inner surface is 30- 80 °, such as 40-65 °.The inner surface can be U- types or v-shaped.Hopper 111 can also have moveable cover（It is not shown）, lid There is the hole for entrance 118 and ventilation opening on body.Hopper 111 can be mounted on pipe 119, by hopper 111 and feed pipe 112 connect.In a specific embodiment, hopper 111 has the equivalent volume for being able to maintain that required throughput rate. For example, hopper 111 can have at least 4 tons of capacity.The maximum gauge of pipe 119 is less than the maximum gauge of hopper 111.As indicated, Pipe 119 has rotary feeder 120 or similar transmission device, for the material in hopper 111 is passed through 129 points of outlet Dispensing feed pipe 112.Rotary feeder 120 can be operated under the pattern that opens or closes or the speed of rotation is controlled to The function of required feed rate.In other embodiments, pipe 119 can be free of internal feeding mechanism.Depending on weight-loss type The type of feeder can be replaced with the external push-and-pull paddle or vibrator that can be distributed the effluent of hopper 111 to feed pipe 112 Swinging feeder 120.Outlet 129 can break AA agglomerates with mechanical means.In another embodiment, weight-loss type into Glassware 110 can contain drier or dry gas cleaning（It is not shown）, to remove the moisture in AA powder, prevent AA powder in hopper It coalesces and is formed in 111 and blocked.

Weight measurement subsystem 121 is connected with hopper 111.Weight measurement subsystem 121 can contain multiple sensors 122, The 122 ponderable quantity hopper 111 of sensor, and will indicate that the signal of weight is supplied to controller 113.In some embodiments In, can there are three or four sensors.Sensor 122 can be connected with the outside of hopper 111, and can weigh tare weight to illustrate The initial weight of hopper 111 and any other equipment being connected on hopper 111.In other embodiments, sensor 122 It may be provided at below hopper 111.According to the signal from weight measurement subsystem 121, controller 113 control supplemental stages and Charging stage.The weight that controller 113 more periodically measures, to determine to distribute to the AA of feed pipe 112 whithin a period of time The weight of powder 102.Controller 113 can also control the rate of spiral propeller 123, as will be explained below.

In other embodiments, weight measurement subsystem 121 may be provided at hopper 111, pipe 119 and feed pipe Under 112, to measure the weight of the material in these positions of loss in weight feeder 110.

Feed pipe 112 can be located at 119 top of pipe, and receive AA powder 102.In one embodiment, feed pipe 112 may be mounted to that on pipe 119.Feed pipe 112 may extend to the plane of the outlet 129 basically perpendicular to pipe 119, Huo Zheyan It extends with the plane in 0-45 °, such as 5-40 ° of angle, and orientating reaction device 140.Feed pipe 112 contains at least one rotating screw AA powder 102 is delivered to by open outlet 124 in reactor 140 by propeller 123, the spiral propeller 123. Spiral propeller 123 is driven by engine 125, and can include screw rod.The configuration of twin-screw can also be used.Engine 125 drive spiral propeller 123 with fixed or variable rate.In one embodiment, feed pipe 112 is by AA powder End 102 is sent to reactor 140 with the feed rate of low variability.The feed rate of AA can be adjusted according to required throughput rate Section.It so allows for setting up fixed AA feed rates and uses model described herein, then change other solution groups Point feed rate to obtain required salinity and/or pH desired values.Controller 113 is received from loss in weight feeder 110 Feedback signal, and adjust the rate of spiral propeller 123.Controller 113 is also according to from weight measurement subsystem 113 Signal adjustment feed pipe 112 feed rate.Giving the command signal of spiral propeller 123 influences the speed of engine Rate, increase maintain or reduce weight loss of the rate of engine to be set.

In other embodiments, feeding line 112 as described herein can be any equivalent, controllable feeder class Type, such as belt feeder, feeder compartment, apron feeder, oscillating feeder.Feed pipe 112 can also include damper（Do not show Go out）.In addition, feeding line 112 can contain one or more gas ports（It is not shown）, for injecting nitrogen to remove oxygen.

Hopper 111 can also contain high-order probe 127 and low level probe 128.Although it should be appreciated that for convenience, only It shows a high-order probe and a low level probe, but can have multiple probes.The probe can be with weight measurement subsystem System 121 is used in combination.In order to realize the present invention, the probe can be point indicator or capacitive proximity sensor.A high position is visited The position of pin 127 and low level probe 128 can be adjusted in hopper 111.High-order probe 127 is positioned proximate to the top of hopper 111 Portion.When the material in hopper 111 is detected by high-order probe 127, terminate supplemental stages, and start the charging stage.It is conversely, low Position probe 128 is located under high-order probe 127, and the bottom of closer hopper 111.Low level probe 128 may be such that tool It is standby in supplemental stages by enough surpluses of allocated AA powder 102.When low level probe 128 detect in hopper 111 When not having material at its position, supplemental stages start.As described above, in supplemental stages, charging can continue.

AA solids are corrosive.Loss in weight feeder 110 can be by the 304a corrosion resistant materials of such as austenitic stainless steel Or such as 304,304L, 316 and 316L or other economically feasible sexual balances being capable of providing between equipment life and cost of investment The material of suitable corrosion resistance constructs.In addition, corrosion resistant material can prevent the corrosion contamination of product.Other are anticorrosive Property material preferably compared with carbon steel, there is higher repellence to the attack of AA.High concentration, the HMD such as higher than 65% do not have carbon steel It is corrosive, therefore carbon steel can be used for storing dense HMD, and stainless steel can be used for storage compared with the HMD of dilute concentration.

Although illustrating only an illustrative loss in weight feeder 110, other acceptable loss in weight feeder can Including Acrison Models402/404,403,405,406 and 407；Merrick Model570；K-Tron Models KT20, T35, T60, T80, S60, S100 and S500；And BrabenderFlex Wall^TMPlus and FlexWall^TMClassic.Acceptable loss in weight feeder 110 allows for reaching the charging speed for being enough continuous business operating Rate.For example, feed rate can be at least 500Kg/hr, such as at least 1000Kg/hr, at least 5,000Kg/hr or at least 10, 000Kg/hr.Higher feed rate can also be used in embodiments of the invention.

Reactor

In one embodiment, the present invention includes to produce the reactor of nylon salt solution, and the reactor includes The continuous stirred tank reactor of nylon salt solution is produced, the continuous stirred tank reactor includes：For dicarboxylic acid powder to be drawn Enter the first entrance of continuous stirred tank reactor, enter for the first diamines to be fed the second of introducing continuous stirred tank reactor Mouthful, wherein second entrance is adjacent with first entrance；The one or more gears being arranged on the inner wall of continuous stirred tank reactor Plate；Extend to the agitating shaft at the center of continuous stirred tank reactor, wherein agitating shaft includes at least one top impeller and extremely A few lower impeller；And comprising for following again in the binding site of the upstream of pump and sample loop introducing the second diamines charging Loop back path；And the pipeline for nylon salt solution to be directly transferred to holding vessel from the recirculation circuit of continuous stirred tank, Described in pipeline without it is any for introduce be selected from by dicarboxylic acids, diamines and its group being bonded other monomers entrance, So as to prevent other monomers being transferred to the pipeline or into holding vessel, wherein the reactor includes single reactor.

As shown in figure 3, nylon salt solution is prepared in single continuous stirred tank reactor 140.Reactor 140 generates foot Enough turbulent flows are to generate homogeneous nylon salt solution.In order to realize the present invention, " continuous stirred tank reactor " is related to one instead Device is answered, not comprising multiple reactors.The present invention can obtain uniform nylon salt solution in single container, need not such as pass The multiple vessel cascades used in system technique.Applicable continuous stirred tank reactor is single container reactor, such as non-series connection Reactor.Advantageously, this can reduce the capital input that nylon salt solution is produced on commercial size.When with mistake described herein When weight formula feeder is used cooperatively, continuous stirred tank reactor can obtain the uniform Buddhist nun for reaching target ph and target salinity Imperial salting liquid.

Nylon salt solution is taken out from reactor 140 and is directly transferred to holding vessel 195.By nylon salt solution from continuous Stirred tank reactor 140 is fetched into 195 period of holding vessel, without the introducing of subsequent monomer AA or HMD.More specifically It says, nylon salt solution is withdrawn from by pipeline 144 from recirculation circuit 141, and is added in without monomer in pipeline 144.One side Face, for pipeline 144 not for introducing the entrance of additional monomers, the additional monomers may include dicarboxylic acids and/or diamines.Therefore, The pH value of nylon salt solution need not be adjusted further by introducing additional monomer into pipeline, particularly without the volume of addition Outer HMD is adjusted.As needed, nylon salt solution can be carried out to additional mixing and filtering, but as being retouched herein It states, monomer should be fed only with single continuous stirred tank reactor.Therefore the technique of the disclosure avoids the need for the sequence of multiple containers The step of with successive pH value measurement and adjustment is considered as between AA and HMD of the maintenance for manufacturing nylon 6,6 before Stablize needed for stoichiometric balance.

Between reactor 140 has 1.5-6, such as the ratio of height to diameter between 2-5.Reactor 140 can be by being selected from by Hastelloy Carbon, aluminium oxide and such as 304, the austenitic stainless steel of 304L, 316 and 316L and other can be in equipment life and cost of investment Between the material of the group that the suitable corrosion-resistant material of economically feasible sexual balance is formed be provided construct.The selection of material can lead to It crosses and considers the temperature in continuous stirred tank reactor 140 to carry out.Residence time in continuous stirred tank reactor 140 according to Size and feed rate and change, and it is typically less than 45min, is such as less than 25min.Liquid withdraws from entrance in outlet at bottom 148 Recirculation circuit 141, and nylon salt solution is withdrawn from pipeline 144.

In general, suitable continuous stirred tank reactor include it is at least one for introducing AA, HMD and/or the monomer of water enters Mouthful.The entrance is directed toward the top of reactor.In some embodiments, monomer is instilled in liquid.In other embodiments, Dip-tube can be used for supplying monomer in liquid level.It can exist for the multiple entrances for each component being introduced into reaction medium. Illustrative continuous stirred tank reactor is as shown in Figure 3.As shown in figure 3, it has AA entrances 145 and HMD entrances 146.Diamines Can with pure HMD or comprising 20-55wt.%, the HMD of such as 30-45wt.% and 45-80wt.%, such as 55-70wt.% water it is water-soluble The form of liquid 106 introduces.Aqueous solution 106 can be introduced by entrance 146, the entrance 146 and the entrance of dicarboxylic acid powder 139 145 is adjacent.In a specific embodiment, entrance 146 can be 0.3-1m from entrance 145.Aqueous solution 106 helps to dissolve, And the dicarboxylic acid powder 139 fed in reactor 140 can be at least partly dissolved.Water can be concomitantly introduced into diamines.Optionally, may be used To be useful for being introduced separately into the entrance 147 of water.Water can also be introduced by reactor recovery tower 131.In certain aspects, recycle Tower 131 is vent condenser.

Liquid in reactor 140 can continuously be withdrawn from and by recirculation circuit 141.Recirculation circuit 141 can include 1 Or multiple pumps 149.Also temperature control equipment can be included in recirculation circuit 141, such as coil pipe, chuck or dress containing heat exchanger It puts, temperature measuring apparatus and controller.Temperature control equipment can control the temperature of the nylon salt solution in recirculation circuit 141, So as to prevent the boiling of nylon salt solution or paddle.As additional HMD, such as supplement HMD is by pipeline 107 when being introduced, and preferably exists One or more pumps the tie point 142 of 149 upstreams and introduces HMD in the upstream of any pH value or salt concentration analyzer.As It is described further herein, the 1-20% to form HMD needed for nylon salt solution can be contained by supplementing in HMD107, such as the 1- of required HMD 10%.Tie point 142 can be the feed inlet of recirculation circuit 141.Except making liquid recycle, pump 149 may also function as secondary mixing The effect of device.Pump can be used for supplement HMD and be introduced into recirculation circuit 141 and will supplement HMD and take out from reactor Liquid mixes.The pump may be selected from by vane pump, piston pump, flexible pump, lobe pump, gear pump, peripheral piston pump and screw rod Pump the group formed.In some embodiments, pump 149 is arranged at tie point 142.In other embodiments, as indicated, pump 149 are arranged on the downstream of tie point 142, but before tie point 143.It is preferred that secondary mixing, which is happened at addition and includes, passes through pipe After all HMD including the supplement HMD of line 107, and before any analysis or taking-up enter holding vessel 195.Optional In embodiment, one or more static mixers（It is not shown）It may be provided in the recirculation circuit 141 in the downstream of pump 149. Illustrative static mixer is in Perry, Robert H., and Don W.Green.Perry's Chemical Engineers'Handbook.7th ed.New York:McGraw-Hill,1997:Have in 18-25to18-34 and further retouch It states, is introduced by reference herein.

In tie point 143, nylon salt solution is withdrawn from pipeline 144.Residence time in pipeline 144 can be according to holding vessel 195 and filter 190 position and change, usually less than 600 seconds, such as be less than 400 seconds.In one embodiment, valve 150 For controlling the pressure of nylon salt solution.Although illustrating only a valve, but it is understood that for can in recirculation circuit 141 Use additional valve.There is no monomer such as AA or HMD to introduce or added in without monomer such as AA or HMD in the downstream of tie point 143 Into pipeline 144.In addition, no monomer is introduced into holding vessel 195 under normal handling conditions.

Recirculation circuit 141 may also comprise to adjust the heat exchanger 151 of the fluid temperature in reactor 140.Temperature It can be exported by using positioned at reactor 140 or continuous stirred tank reactor 140（It is not shown）Temperature controller（It is not shown） It is adjusted.The temperature of liquid can utilize inner heat exchanger, such as coil pipe or jacketed reactor（It is not shown）It is adjusted.It can be to The cooling water more than solidification point for the salt that the supply of heat exchanger 151 maintains given concentration.In one embodiment, heat exchange Device can be indirect shell-and-tube exchanger, spiral shape or plate and frame heat exchanger or be used to come the recycling heat of autoreactor 140 Reboiler.In the range of temperature in reactor 140 maintains 60-110 DEG C, to prevent from slurries from being formed and crystallize to be formed.When During water content increase, the temperature needed for solution is maintained to decline.In addition, the temperature in reactor 140 maintains low temperature to prevent HMD Oxidation.Also blanket of nitrogen can be provided to prevent the oxidation of HMD.

As shown in Figure 3, in a specific embodiment, reactor 140 has internal coil 152, to described interior Portion's coil pipe 152 feeds cooling agent and is in adjusting the temperature of reactor in the range of 60-110 DEG C.In another specific implementation In scheme, reactor 140 can also have the chuck with cooling agent（It is not shown）.Internal coil can also be generated by recycling reaction Heat adjust temperature.

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

In a specific embodiment, also can have sample line 153, for measure the pH value of nylon salt and/or Salinity.Sample line 153 can be with recirculation circuit 141 there are fluid communication, and preferably therefrom receives fixed flowing to incite somebody to action The influence to analyzer is flowed to minimize.On the one hand, sample line 153 can withdraw from being located at less than 1%, more preferably less than 0.5% Nylon salt solution in recirculation circuit 141.Sample line 153 can there are one or multiple analyzers 154.In some embodiment party In case, sample line 153 can include filter（It is not shown）.In another embodiment, sample line 153 can include Suitable heating or cooling device, such as heat exchanger are to adjust and control the temperature of sample flow.Similarly, sample line 153 can Comprising for into sample flow plus water is to adjust the water charge line of concentration（It is not shown）.If adding in water into sample flow, water It can be deionized water.The water that there is provided by sample line 153 is calculated to maintain target salinity, and adjustable other water into Material.Analyzer 154 can include the in-line analyzer measured in real time.According to the type of sampling, the part tested can pass through Pipeline 155 is back in reactor 140 or discharges.Sample line 153 can be returned by recirculation circuit 141.Optionally, Sample line 153 can be back to reactor 140 in individual position.

Continuous stirred tank reactor 140 keeps at least 50% full, such as at least 60% full liquid level.The liquid level is selected to cause Buddhist nun Imperial salting liquid can submerge the paddle of CSTR, so as to prevent nylon salt solution from forming foam.Nitrogen or other inert gases can pass through Stomata 157 is introduced into 156 superjacent air space of liquid level.

The inside of continuous stirred tank reactor 140 can provide enough mixing to obtain having the nylon salt of homogeneous pH value molten Liquid.As shown in Figure 4, there is the agitating shaft 159 at the center for extending perpendicularly to reactor 140 and passing through reactor 140.It is preferred that Ground, agitating shaft 158 extends along the center line of reactor 140, but in some embodiments, agitating shaft 158 may pass through center.It is in office In the embodiment of choosing, agitating shaft can be inclined.As long as the stirring for reaching required can be crossed, it is possible to use eccentric agitating shaft.

Agitating shaft 158 can contain one or more impellers 159, as agitating paddle, hurricane band, anchor, spiral, propeller and/or Turbine type.It is preferred that aial flow impeller is used to mix AA and HMD, this is because this kind of impeller trend prevents solid particle in reactor 140 bottom sedimentation.In other embodiments, impeller can be flat paddle radial turbine, have around disk Several equidistant blades.2-10 impeller can be contained in entire agitating shaft 158, such as 2-4 impeller.Blade 160 on impeller 159 Can be straight, curved formula, female, male, it is angled or oblique.The number of blade 160 can be in 2-20, such as 2- Change between 10.If necessary, blade 160 can also have balancer（It is not shown）Or scraper（It is not shown）.

As shown in Figure 4, which show three to tilt turbine assembling 161.Agitating shaft 158 includes the oblique leaf at least one top Turbine 162 and at least one lower part inclined blade turbine 163.In three tilt turbines assembling 161, preferred top inclined blade turbine 162 Inclined-plane 164 and the inclined-plane 164 ' of lower part inclined blade turbine 163 are mutually offset.

A variety of agitating shafts with different types of impeller can also be used, such as screw agitation shaft and anchor agitator shaft.Also Side suspension agitator shaft, especially marine propeller can be used.

Fig. 3 is back to, agitating shaft 158 is driven by outer 165, can be in 50-500rpm, such as 50-300rpm Speed mixing liquid.Agitating shaft 158 is removably mounted at connector 167 in engine shaft 166.The speed of movement It is variable, but under normal conditions, the speed must maintain the whole table area of solid particle to be contacted with liquid phase enough, so as to ensure Interfacial area is used for the maximum availability of the mass transfer of solid-liquid.

Reactor 140 can also include one or more baffles 168, for mixing and preventing dead angle from being formed.The number of baffle 168 Mesh as changed in the range of 2-10, and can be evenly distributed on the periphery of reactor 140 in 2-20.Baffle 168 can be mounted on reaction On the inner wall of device 140.Usually using vertical baffle, but curved baffle can also be used.Baffle 168 may extend to higher than reactor Liquid level 156 in 140.

In one embodiment, reactor 140 include be used for by pipeline 135 remove tail gas exhaust outlet and for will Compressible HMD is back to the recovery tower 131 of reactor 140.Water 132 can be fed into recovery tower 131, and in recovery tower 131 Bottom 133 be recovered.Water 132 feeds to maintain the efficiency of recovery tower 131 with minimum rate.Water is calculated to maintain target Salinity, and adjustable other water chargings.Discharge gas 134 can be condensed to recycle any water and monomer tail gas, and can return It is back to pipeline 133.The gas of incoagulability comprising nitrogen and air can be removed as tail gas stream 135.When recovery tower 131 is During vent condenser, recovery tower 131 can be used for recycling tail gas and removal incoagulable gas.

The storage of nylon salt solution

As shown in figure 3, after nylon salt solution is formed, holding vessel 195 is supplied into, the nylon salt solution can be protected There are needed in holding vessel 195 up to polymerizeing.In some embodiments, holding vessel 195 can include recirculation circuit 193, use To cycle nylon salt solution.Internal spray mixer 194 can be used to maintain the cycling in holding vessel 195.It is specific at one In embodiment, internal spray mixer 194 may be provided at 195 bottom 0.3-1.5m of holding vessel, at preferably 0.5-1m. In addition, in some embodiments, at least part nylon salt solution may return in reactor 140, to prevent process pipelines from freezing It ties and/or adjusts nylon salt solution when system perturbations or target ph and/or target salting liquid need variation.Carry out auto polymerization work Any untapped nylon salt solution of skill 200 also may return to holding vessel 195.

Holding vessel 195 can by being selected from by austenitic stainless steel, such as 304,304L, 316 and 316L or other can be in equipment The material that the group of the suitable corrosion-resistant material composition of economically feasible sexual balance is provided between service life and cost of investment constructs. According to the size of holding vessel and the volume of nylon salt solution to be stored, holding vessel 195 can include one or more holding vessels. In some embodiments, nylon salt solution is stored at least two holding vessels, such as at least three holding vessel, at least four holding vessel Or at least five holding vessel.Holding vessel 195 can be maintained at the temperature higher than solution solidification point, such as between 60-110 DEG C.By In nylon salt solution salinity for 60-65wt.%, therefore temperature is positively retained between 100-110 DEG C.Can have in holding vessel Interior heater 196.In addition, recirculation circuit can contain one or more heaters 197, for providing heat to holding vessel.Example Such as, holding vessel can have the capacity for accommodating and up to 5 days stocks, being more preferably up to the nylon salt solution of 3 days stocks.Holding vessel can be Normal pressure or slightly higher than normal pressure are kept in blanket of nitrogen.

In some embodiments, before holding vessel 195 is entered, nylon salt solution can be filtered to remove impurity. Nylon salt solution can be by least one filter 190, and such as at least two filters or at least three filters are filtered.It crosses Filter 190 can be set in parallel or series.Suitable filter may include containing polypropylene, cellulose, cotton and/or glass fibre Membrane filter.In some embodiments, between the aperture of filter is 1-20 microns, between 2-10 microns.The mistake Filter is alternatively ultrafilter, Microfiltration Unit, nanofilter or active carbon filter.

Supplement HMD

As described above, it forms two positions of HMD in the process used in nylon salt solution and adds in not Same part, main HMD and supplement HMD.In order to allow using single continuous stirred tank reactor and form homogeneous nylon salt Solution once nylon salt solution is taken out from reactor 140 into pipeline 144 and subsequently enters holding vessel 165, is then added without HMD.The control for deviateing the difference of target component such as target ph can be by comprising as shown in Figure 5 at tie point 142 Come via the supplement HMD of pipeline 107 further accurate.The minimum part that HMD is typically added in HMD is supplemented, as Buddhist nun The subtle adjustment of imperial salting liquid pH value this is because being compared with main HMD chargings, can be controlled preferably using smaller valve The minor variations of flow.The delay between adjustment and pH value measure due to main HMD, it is less preferred using the main HMD's of adjustment The method of feed rate or flow rate controls the pH value of nylon salt solution.Further, since supplement HMD is incorporated into CSTR's The minimum part of HMD, supplement HMD allows to more accurately adjust the pH value of nylon salt solution, and pH analyzers provide Nearprompt feedback.It supplements HMD to add in the upstream that pH is measured, to reduce in terms of measurement adds in supplement diamines to pH value influence Delay.When adjustment supplements HMD, water feed rate can also be adjusted to control the solid concentration in nylon salt solution.Such as this Described in text, this adjustment can be set with controller and the refractometer in sample line 153 can use to be monitored.

Supplement HMD107 can be mixed before it enters pipeline 144 with nylon salt solution.Although being fettered without theory, can with Think that supplementing HMD107 can react with any remaining free AA in nylon salt solution.In addition, as described above, add in supplement HMD107 can be used for the pH value of adjustment nylon salt solution.

In one embodiment, the present invention relates to based on weight metering from loss in weight feeder 110 to feed pipe AA powder, it is anti-that the AA powder feeds 139 of metering are transferred to continuous stirred tank by the feed pipe with the charging rate of low variability It answers in device 140；The aqueous solution 106 comprising first portion HMD104 and water 103 is individually introduced into continuous stirred tank reactor Nylon salt solution is formed in 140；And second portion HMD, such as supplement HMD are introduced by nylon salt solution by pipeline 107 In.It can be added in tie point 142 by HMD107 is supplemented in the nylon salt solution in recirculation circuit 141.Supplement HMD107 with Certain feed rate is constantly added in recirculation circuit 141, and certain feed rate enables to supplement HMD107 Flow to pass through the middle-grade flow of valve, such as 20-60%, 40-50% or about 50%.Middle-grade flow refers to maintain through valve Continuous flow is out of hand to prevent.

To obtain having the target ph of low variability, the technique provides AA powder using loss in weight feeder 110 102 constant feed rate and the feed rate of adjustment HMD and water is controlled with response technique.Advantageously, from continuous work High production rate is obtained in skill.When changing salt throughput rate, since AA feed rates change in discrete time interval, HMD Feed rate can be adjusted proportionally.The feed rate or supplement that the feed rate of HMD can be fed by changing main HMD The feed rate of HMD is adjusted.In a preferred embodiment, for given salt throughput rate, can adjust The feed rate of HMD107 is supplemented, and the feed rate of HMD104 or the feed rate of HMD aqueous solutions charging 106 can be constant. In optional embodiment, if necessary, the feed rate of supplement HMD107 may be set to constant speed, and HMD104 is adjusted Feed rate or HMD aqueous solutions charging 106 feed rate to reach target ph and/or target salinity.Other one In a little embodiments, HMD104 is adjusted and supplements the feed rate of HMD107 or the feed rate of HMD aqueous solutions 106 to reach To target ph and/or salinity.

Identical HMD sources can be had with HMD104 by supplementing HMD107.HMD104 can include total HMD in nylon salt solution 80-99%, such as 90-99%.The 1-20%, such as 1-10% of total HMD in nylon salt solution can be included by supplementing HMD107.HMD104 and benefit Filling the ratio of HMD107 can be adjusted according to target ph and target salinity.As discussed herein, HMD104 and benefit The ratio for filling HMD107 can be by being used for the model specifications of total HMD feed rates.

HMD can be supplied in the form of pure HMD, such as containing at least 99.5wt.%HMD, such as 100%HMD and anhydrous or to contain The form supply of the aqueous solution of 80-99.5wt.%HMD.Supplement HMD107 can be fed into the form of pure HMD or HMD aqueous solutions Nylon salt solution.When it is HMD aqueous solutions to supplement HMD107, the HMD of 50-99wt.% can be included by supplementing the aqueous solution of HMD107, Such as the HMD of at least 60-95wt.% or 70-90wt.%.When the aqueous solution is used for HMD104, the amount of water can the source based on HMD It is adjusted with the target salinity of nylon salt solution.Advantageously, the HMD concentration of HMD107 is supplemented as 90-100wt.%, from And while supplement HMD107 is made to minimize the influence that salinity controls, improve its influence to pH value control.

In the nylon salt solution that supplement HMD107 is added in the upstream of pump 149 and sample line 153 in recirculation circuit. It adds in after supplement HMD107, nylon salt in recirculation circuit 141 can be measured with analyzer 154 on sample line 153 The pH value of solution.This allows for having small prolong by supplementing the feed rate of HMD107 and adjusting between pH value and pH value measure Late.There is no additional AA to be added in recirculation circuit 141.In addition to supplementing HMD107, no HMD is added to recirculation circuit In 141.It supplements HMD107 to add in the upstream that pH value measures, be measured with allowing to include the pH value for supplementing HMD.

Different from the existing process shown in US2010-0168375 and US4233234, supplement HMD is not measured in pH value After add in.Being added in after pH value measure can cause measuring the HMD added in the big delay in the influence of pH value, this is because The HMD of addition has to flow through reactor before measured.Thus, adding in HMD in this way can be less than or more than target ph, This will cause these techniques to pass through constantly pursuing of goal pH value inefficiently to run.Advantageously, the present invention is surveyed in pH value Fixed upstream adds in supplement HMD, so that the influence of supplement HMD results only in small delay, and avoids below or above mesh The problem of marking pH value.Further, since valve maintains middle-grade flow, supplement HMD107 is continually added in the present invention.

Technology controlling and process

As described herein, in prior art processes for generating polyamide salt solution, the company of such as nylon salt solution In continuous technique, the target component in nylon salt solution including pH value and salinity, has variability.Target component it is this Variability can at least partly be caused by uncertain and fluctuation AA powder feed rates.This unpredictability and fluctuation make Technique be difficult to control, this is because this technique must the downstream of initial reactor, before storage constantly monitoring and It adjusts.Thus, the single reactor continuously run is difficult to efficiently against this uncertain and fluctuation AA powder feeds Rate.Traditionally, in order to overcome this unpredictability and fluctuation, using several reactors, mixer and multiple monomer feeds Position produces the nylon salt solution with target component particularly with the addition of the position of HMD.According to the present invention, using single continuous Stirred tank reactor removal adjusts the ability of the nylon salt solution in several reactors.However, by using loss in weight feeder Unpredictability and the fluctuation of AA powder feed rates are reduced, AA powder feed rate of the variation less than ± 5%, this hair can be obtained It is bright to utilize the feedforward control based on model, with reference to or do not combine feedback information, to obtain with target ph and target salt The nylon salt solution of concentration.

Feedforward control

Between the continuous processing of production nylon salt solution starts, it can be set up based on the productivity of required nylon salt solution Reaction model.Based on the productivity, AA powder feed rates, pH value of then setting objectives and target salinity are set.Then HMD feed rates and water feed rate are calculated by stoichiometric ratio to reach target ph and target salinity.HMD charging speed Rate includes main HMD and supplement HMD.Water feed rate includes feeding the water in all sources of reactor 140.It should be appreciated that It is that target ph reflects the target molar ratio of AA and HMD.In a further embodiment, additional feature can be added to institute It states in model, includes but not limited to reaction temperature and reaction pressure.The model is used to be the HMD into continuous stirred tank reactor And/or the feed rate of water sets feedforward control.

In some embodiments, the charging of the AA powder provided by input by loss in weight feeder described herein Rate sets up model.For a given productivity, the feed rate of AA should be constant.As described herein, Loss in weight feeder can include discrete control to generate the AA powder feed rates with low variability.From loss in weight feeder AA powder feed rates can be continuously, semi-continuously or in discrete time intervals, such as every 5 minutes, every 30 minutes or per hour It is supplied to the model.In in other respects, due to the low variability of AA powder feed rates, once AA powder feed rates are set Fixed, then the model can set the feed rate of HMD and the feed rate of water.These feed rates by the model specification, To obtain target ph and target salinity.

The model can be dynamic, and can be adjusted according to from online or off-line type analyzer feedback signal Section.For example, if necessary to change productivity, pH value and salinity, model can be adjusted.The model can be stored in control In the memory of device, such as programmable logic controller (PLC)（PLC）Controller, dcs（DCS）Controller or ratio-product Point-differential（PID）Controller.In one embodiment, the PID controller with feedback signal can be used for illustrating that model calculates With the error in flow measurement.

The feed rate of Accurate Prediction AA powder is unable to due to the use of volumetric feeder, is formed and deviateed by feedforward control entirely The nylon salt solution of target component low rate of change is being unpractical before.This is fed due to the use of positive displacement at least partially The variation of AA powder feed rates caused by device.Due to the variability of AA powder feeds, model can not be established for controlling AA and HMD Ratio.Therefore, these traditional handicrafts can use feedback control, thus need continually to adjust or for batch technology.However, When entering the AA powder of continuous stirred tank reactor based on weight metering, feedforward control is just enough continuous production with low rate of change Deviate the nylon salt solution of target component.

Thus, in one embodiment, the work continuously prepared for being used to control nylon salt solution the present invention relates to one Skill, including：Generation is for setting the model of the target feed rate of dicarboxylic acid powder, to generate the nylon salt with target ph Solution；Based on weight, the dicarboxylic acid powder from loss in weight feeder to feed pipe is measured, so as to which dicarboxylic acid powder be controlled to feed Dicarboxylic acid powder is transferred to single continuous stirred tank reactor by the variability of rate, the feed pipe with target feed rate In；Diamines and water are introduced into the first feed rate and the second feed rate in single continuous stirred tank reactor respectively, wherein First feed rate and/or the second feed rate are based on model；And by nylon salt solution from single continuous stirred tank reactor In be continuously taken out being sent directly into holding vessel, wherein the deviation value of the pH value for the nylon salt solution taken out and target pH less than ± 0.04。

Schematic diagram is shown in order to further illustrate process according to the invention control program, such as Fig. 6.To put it more simply, Fig. 6 In without showing multiple pumps, recirculation circuit and heater.Many streams for the flow in measuring system are shown in figure 6 Gauge, such as coriolis mass flowmeters, positive displacement flow meter, electromagnetic flowmeter and turbine flowmeter.In some embodiment party In case, flowmeter can also measure temperature and/or density.The output signal of flowmeter can continuously or periodically be input to control In device 113.Preferably, there is at least one flowmeter in the upstream of each flowmeter valve.In some embodiments, these Flowmeter and flowmeter valve can be whole, and be provided together in the form of compact apparatus.Although illustrate only a control Device in some embodiments, can there is multiple controllers.As shown in Figure 6, AA powder feeds weight-loss type by pipeline 102 In feeder 110, to generate the AA powder feeds 139 of metering.Controller 113 send signal 211 to spiral propeller 123.Signal can be wireless signal.Using model, the feedforward feed rate model of HMD and water can be stored in controller 113. As described above, loss in weight feeder 110 adjusts the variability of AA powder, so as to provide the metering that low variability deviates target feed rate AA powder feeds 139.For example, loss in weight feeder 110 can use the backfeed loop from weight measurement subsystem 121, To adjust the rate of spiral propeller 123.

Controller 113 sends feed-forward signal 213 and enters reactor 140 by pipeline 106 to flowmeter valve 214 to adjust The flow of water 103.Similarly, controller 113 send feed-forward signal 215 to flowmeter valve 216 so as to adjust by pipeline 106 into Enter the flow of the HMD104 of reactor 140.These feed-forward signals are by model specification to reach target ph and target salinity. In another embodiment, controller 113 sends feed-forward signal（It is not shown）Give flowmeter valve（It is not shown）To adjust into anti- Answer the feed rate of the HMD aqueous solutions 106 of device 140.Due to feed-forward signal 213 and 215 be used for into reactor 140 HMD and Water, therefore online or off-line type measure is carried out to HMD aqueous solutions 106 and is not required in that.Additionally, there are be conveyed to flowmeter The feed-forward signal 217 of valve 218, to adjust the flow into the supplement HMD107 of recirculation circuit 141.Model can determine to pass through The relative quantity of the HMD chargings of main HMD and supplement HMD.Adjust feed-forward signal 217 is with the flowmeter valve 217 of guarantee supplement HMD Middle-grade output flow.In one embodiment, model can set up feed rate, and flow is reached by feed-forward control signals 217 Metering valve 218, to ensure to maintain the constant flow from supplement HMD107, i.e. middle-grade flow.

Secondary process controls

Except as shown in Figure 6 based on modeling using feedforward control, technology controlling and process may include feedback signal as two level Technology controlling and process, to obtain target ph and target salinity.These feedback signals can be from for adjust HMD and water charging, Especially supplement the flowmeter of HMD and water charging and the measured value of in-line analyzer 154.In-line analyzer 154 may include that pH is visited Pin, refractometer and its combination.These pH probes and refractometer can be in parallel or series.

As described herein, when based on weight metering AA powder, the feed rate of AA powder has low variability. This low variability provides reliable AA powder feed rates, improves the ability and base for reaching target ph and target salinity The ability of HMD and water feed rate is adjusted in feedback signal.Therefore, in a specific embodiment, the present invention relates to one For controlling the technique continuously prepared of nylon salt solution, including：It generates to set the target feed rate of dicarboxylic acid powder Model, with generate with target ph nylon salt solution；Based on weight, measure from loss in weight feeder to feed pipe Dicarboxylic acid powder, so as to control the variability of dicarboxylic acid powder feed rate, the feed pipe by dicarboxylic acid powder with target into Material rate is transferred in single continuous stirred tank reactor；And respectively by diamines and water with the first feed rate and the second charging speed Rate introduces single continuous stirred tank reactor, to produce the nylon salt solution with target ph；It will be mended with the 3rd feed rate Diamines is filled to be continually introduced into the recirculation circuit of single continuous stirred tank reactor；Introducing the downstream of supplement diamines, profit With the variation of the pH value of the online pH measured values monitoring nylon salt solution of nylon salt solution；The 3rd feed rate is adjusted to respond pH The variation of value, to generate the nylon salt solution that pH value deviates target pH and is less than ± 0.04.

As shown in Figure 7, the online analyzer 154 of technology utilization, such as online pH meter 154 generate feedback signal, with measurement The pH value of nylon salt solution in recirculation circuit 141.In order to be conducive to the on-line measurement of the pH value of nylon solution, by nylon salt Solution is continuously taken out from reactor, and at least a portion nylon salt solution is imported recirculation circuit 141 and sample line 153.Recirculation circuit 141 may include flowmeter（It is not shown）With flowmeter valve.In another specific embodiment, recycling Circuit 141 can include pressure controller（It is not shown）, to control the flowing of nylon salt solution.Preferably, recirculation circuit is flowed through The flow of 141 nylon salt solution is constant.Sample line 153 includes the device such as pH meter and/or salt measured for pH value The device of concentration mensuration such as refractometer.In a specific embodiment, the pH value of at least a portion nylon salt solution is being reacted It is measured under the conditions of device, without any dilution or cooling.Then this at least a portion nylon salt solution is condensed directly or by exhaust Device 131 is back to reactor 140.When this at least a portion nylon salt solution is back to reactor by vent condenser 131, Nylon salt solution can replace feeding the water of vent condenser.Sample line 153 can also include to cool down before pH value is measured The cooler of nylon salt solution（It is not shown）With the temperature sensor for the measuring temperature before pH value is measured（It is not shown）. In some specific embodiments, before pH value determination, nylon salt solution is cooled to target temperature.This target temperature can be Than present in reactor 140 in the target zone of low 5-10 DEG C of nylon salt solution.This temperature can deviate target temperature and be less than ± 1 DEG C, such as change less than ± 0.5 DEG C.There can be temperature sensor（It is not shown）, to monitor the nylon salt that upstream is measured in pH The temperature of solution.

Then online pH meter 154 provides output signal 226 and arrives controller 113.This output signal 226 measures online pH meter PH value pass to controller 113.Online pH meter is used to measure the variation of the pH value of nylon salt solution in a continuous process.Change sentence Talk about, due to the condition of variation, online pH meter can measure from target ph can be different pH value, but when measurement pH value have change During change, controller 113 adjusts the charging of monomer.In preferred embodiments, the variation of the pH value of nylon salt solution less than ± 0.04, such as less than ± 0.03 or less than ± 0.015.Due to the offset of online pH meter measured value, online pH meter is used to measure pH's Variability rather than pH absolute values.This is attributed to the feedforward control that can set target ph at least partly.If pH value changes, It is measured by using online pH meter, the variation in production technology can be detected.Using Two-stage control, the variation of pH value can cause by Signal wire 215 and 217 is respectively fed at least one corresponding adjustment in the feed rate of flowmeter valve 216 and 218.To provide Sensitive pH value is adjusted, and is sent signal to valve 218 by line 217 and is supplemented HMD107 to adjust.The tune done to supplement HMD107 Whole amount can be taken in by the corresponding change made through flowmeter valve 216 to main HMD104.What this adjustment was in response to, one Denier does not show that pH value changes, should be able to be recovered to the feed rate of feedforward control setting.Also may be used to the adjustment for supplementing HMD107 Influence the salinity of nylon salt solution.The variation of such salinity can be adjusted by signal 213 by the water of flowmeter valve 214 come Control.

Since the described technique for being used to form nylon salt solution is continuous, the pH measured values in online pH meter 154 It can be real-time（As continuously）Or near real-time obtains.In some embodiments, pH value measures every 60 minutes, such as every 45 minutes, every It carries out within 30 minutes, every 15 minutes or every 5 minutes.The accuracy of pH meter is in the range of ± 0.05, in the range of ± 0.02.

Except online pH meter 154, the technique can further include the salinity using refractometer measurement nylon salt solution, And adjustment water feed rate.In one embodiment, the feed rate of water can be adjusted by feeding the water of recovery tower 131.Salt Concentration can be by adding in or going to remove water to adjust into the nylon salt solution of reactor downstream.

According to the required adjustment based on feedback, model can also adjust main HMD and water using Two-stage control.Work as pH When tending to cause the long-run adjustment of supplement HMD107, this control is especially beneficial.

Except the feedback information from online pH meter 154, can be given per flow meters controller 113 provide information or quality into Expect rate.As shown in Figure 7, all it is connected per flow meters valve with flowmeter, the flowmeter is preferably able to measurement mass flow. Flowmeter 214 ' provides information by pipeline 213 ' to controller 113.Flowmeter 216 ' is carried by pipeline 215 ' to controller 113 For feedback information.Flowmeter 218 ' provides feedback information by pipeline 217 ' to controller 113.Information from flowmeter can use In the total feed rate of maintenance.

It has been disclosed using the existing process of the pH value of pH probes measurement nylon salt solution.Referring to US4233234 and US2010/0168375.However, these existing process of each single item measure the pH value of nylon salt solution, additional two are then added in Amine and/or acid adjust pH value.The effect of additional diamines and/or diacid is until additional diamines and/or diacid is mixed into Reactor is simultaneously withdrawn from from reactor and is measured and can determine again.The method causes " chasing " pH value, and causes and can be more than Or insensitive technology controlling and process less than target ph.

In the present invention, as shown in Fig. 3,5,6,7,8 and 9, supplement HMD107 is preferably added in the upstream of online pH meter.Cause And the HMD supplemented in HMD107 is mixed with nylon salt solution in reactor recirculation circuit, and be recycled through instead at it Answer the pH value that nylon salt solution is measured before device 140.

Secondary process control with the measurement of online experiment room

As described above, the pH value measurement from secondary process control not necessarily reflects target ph, but for illustrating The variation of pH value.In order to improve the sensibility of pH value measure, secondary process control can also refer to measure Buddhist nun under controlling in laboratory The pH value of imperial salting liquid.Although being not bounded by theory, due to improving nearly yield point under the concentration and temperature conditionss of reduction The sensibility of the pH value measurement at place, therefore the pH value that nylon salt solution is measured under being controlled in laboratory improves the accurate of measurement Degree.This may be such that be able to detect that at reaction conditions may without noticing of small pH variation.In order to realize the present invention's Purpose, laboratory condition refer at 15-40 DEG C, and nylon salt solution sample is measured such as 20-35 DEG C or at a temperature of 25 ± 0.2 DEG C Product.The nylon salt solution sample measured in laboratory conditions has the salinity of 8-12%, such as 9.5%.In laboratory conditions The measure of pH value can online be carried out by diluting and cooling down the nylon salt solution in sample line 153.

Therefore, in one embodiment, the present invention relates to one for controlling the technique continuously prepared of nylon salt solution, Including：It generates to set the target feed rate of dicarboxylic acid powder to generate the mould of the nylon salt solution with target ph Type；Based on weight, the dicarboxylic acid powder from loss in weight feeder to feed pipe is measured, so as to control dicarboxylic acid powder charging speed Dicarboxylic acid powder is transferred to target feed rate in single continuous stirred tank reactor by the variability of rate, the feed pipe； And be respectively introduced into diamines and water in single continuous stirred tank reactor with the first feed rate and the second feed rate, with production Nylon salt solution with target ph；To supplement diamines with the 3rd feed rate, to be continually introduced into single continuous stirred tank anti- In the recirculation circuit for answering device；The sample part of nylon salt solution is obtained in the downstream for introducing supplement diamines；By sample part into Row dilution and cooling, to form the diluted nylon salt solution of concentration and 15-40 DEG C of temperature with 5-15%；It is mended using introducing Fill the variation of the pH value of the diluted nylon salt solution of online pH measured values monitoring of the nylon salt solution in diamines downstream；Adjust the 3rd Feed rate responds the variation of pH value, to produce the nylon salt solution that pH value deviates target ph and is less than ± 0.04.

It as shown in Figure 9, will in order to be conducive to carry out on-line testing to the pH value of nylon salt solution in laboratory conditions Nylon salt solution is continuously withdrawn from from reactor, and by least a portion nylon salt solution, such as less than 1% import be recirculated back to Road 141 and sample line 153.Sample line 153 is included for the device of pH value determination in laboratory conditions.Sample line 153 can also include cooler（It is not shown）, to cool down nylon salt solution.In other examples, which can omit.Sample The temperature and concentration of nylon salt solution in quality control line 153 can be adjusted by adding in water through pipeline 220.The water is by model meter The sub-fraction for the total water feed rate calculated.The water is being sufficiently achieved for the diluted nylon salt solution sample of pH value measure It is added under the addition and temperature conditionss of temperature and concentration needed for product.In the technique also can include to diluted sample into One step cools down.The pH value of at least a portion nylon salt solution is measured in laboratory conditions, and then this at least a portion Nylon salt solution is back to reactor 140 as described herein.Then online pH meter is supplied to controller 113 by signal 226 is exported.

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, such as less than ± 0.03 or less than ± 0.015.Similar to reaction condition Under pH value measurement, due to the offset of online pH meter measured value, online pH meter in laboratory conditions be used to measure pH's Variation rather than target ph.This is at least partly the feedforward control due to that can set target ph.If pH value changes, It is measured by using online pH meter, can detect the variation of production technology.Similar to secondary process control, can pass through to Pipeline 215 and 217 sends a signal to flowmeter valve 216 and 218 feed rate to be adjusted.These adjustings can also influence Buddhist nun The salinity of imperial salting liquid.The variation of such salinity can be controlled through the water of flowmeter valve 214 to be controlled by signal 213 System.

Since the described technique for being used to form nylon salt solution is continuous, the pH value measurement in online pH meter 154 It as a result can be in real time（As continuously）Or near real-time obtain.In some embodiments, the measurement of pH can be 60 minutes every, such as every 45 minutes, 30 minutes every, every 15 minutes or progress in every 5 minutes.The accuracy of the measuring method of pH value is ± 0.05, such as ± 0.03 Or ± 0.01.

Three-level technology controlling and process

Although reduction nylon salt solution parameter can help to using feedforward control and feedback signal as shown in Fig. 6,7 and 9 Variability, but the off-line type pH value carried out under further analysis, especially laboratory condition can be used and analyze to monitor nylon The homogeneity of salting liquid.These in laboratory conditions offline process control, referred to as three-level technology controlling and process, it may include pH value Measurement and/or the measurement of salinity.In one embodiment, the pH value of nylon salt solution can carry out in laboratory conditions from Wire type measures, to determine whether to reach target ph.The measurement of off-line type pH value also can detect any plant issue or adjustable Whole deviation.In another embodiment, the pH value of the nylon salt solution measured offline in laboratory condition can also be used for adjusting The whole signal pipe line 215 and 217 for being connected to flowmeter valve 216 and 218.The measurement energy of off-line type pH value in laboratory conditions Enough measure pH value ± 0.01.

Thus, in one embodiment, the present invention relates to one for controlling the technique continuously prepared of nylon salt solution, Including：Generation is molten to generate the nylon salt with target ph for setting the model of the target feed rate of dicarboxylic acid powder Liquid；Based on weight, the dicarboxylic acid powder from loss in weight feeder to feed pipe is measured, so as to control dicarboxylic acid powder charging speed Dicarboxylic acid powder is transferred to target feed rate in single continuous stirred tank reactor by the variability of rate, the feed pipe； And diamines and water are introduced into single continuous stirred tank reactor with the first feed rate and the second feed rate respectively, to generate tool There is the nylon salt solution of target ph；Diamines will be supplemented with the 3rd feed rate and be continually introduced into single continuous stirred tank reaction In the recirculation circuit of device；Sample is removed from the nylon salt solution in downstream of supplement diamines is introduced into, at 15-40 DEG C The off-line type pH value measurement of nylon salt solution is carried out in aqueous solution；It is inclined to determine that online pH value measurement is measured with off-line type pH value Difference；Nylon salt is monitored using the on-line pH value measurement result devious for the nylon salt solution that downstream is introduced positioned at supplement diamines The variation of the pH value of solution；And the 3rd feed rate is adjusted to respond the variation of pH value, deviate target ph to generate pH value Nylon salt solution less than ± 0.04.

As shown in Figure 8, at least a portion of the nylon salt solution in sample line 153 is directed to through online pH meter 154, pH value measurement result is obtained wherein, and is exported signal 226 and be directed to controller 113.Sample line 153 can also include Cooler（It is not shown）, to cool down nylon salt solution before pH meter 154 is flowed through.Nylon salt solution in sample line 153 At least a portion can be removed by pipeline 221, and measured with laboratory pH meter 222.Water adds in pipeline by pipeline 220 Sample is diluted to specific concentration in 221, then it is cooled to target temperature again, as between 15-40 DEG C or 25 DEG C nearly. In one embodiment, cooling water can be used for diluting and cooling down sample.The pH value of nylon salt solution in pipeline 221 is tested Amount, and export signal 226 and be sent to controller 113.Then the nylon salt solution part tested in laboratory conditions can be with returning The sample after tested of return line 155 is combined, and is then back to reactor 140 by pipeline 224.In some embodiments In, the nylon salt solution part tested in laboratory conditions can be fallen by the outside drain of pipeline 223 from technique 100.

To reach laboratory condition temperature and concentration, the nylon salt solution sample removed from recirculation circuit can be used through pipe The water that line 220 adds in is diluted and cools down.Temperature bath can also be used to cool down diluted nylon salt solution sample.Sample can root According to need withdraw from, such as per 4-6 it is small when, daily or weekly.In system perturbations, sample can more frequently, as per hour It is removed.In general, off-line type pH analyzers can be used for the Deviation of equipments for illustrating in-line analyzer.For example, if target ph is 7.500, online pH analyzers can measure 7.400 and off-line analysis instrument can survey 7.500, this indicates that the equipment of online pH analyzers Deviation.In one embodiment, whenever off-line measurement is carried out, exponentially weighted moveing average can be used for automatically deviateing online Analyzer.In some embodiments, the output of off-line analysis instrument can be used for any deviation or the offset of correction in-line analyzer. In other embodiment, although in-line analyzer is not corrected, offset or deviation are monitored using off-line analysis instrument.In this side Face determines the variation of pH value by in-line analyzer, as being located at outside default acceptable variability.

In other embodiments, the target salinity of off-line analysis instrument measurement nylon salt solution can be used.Offline salt is dense Degree measurement result also can detect any plant issue or adjustable deviation.When using multiple refractometers, each refractometer It can independently bias.

Nylon polymerization

Nylon salt solution described herein can be guided in polymerization technique 200, to form polyamide, especially nylon 6, 6.Nylon salt solution directly can be sent to polymerization technique 200 by continuous stirred tank reactor 140 or be first stored in holding vessel 195, Polymerization technique 200 is then sent to, as shown in Figure 10.

The nylon salt solution of the present invention has homogeneous pH value, can improve the performance of polymerizing polyamide technique.Have The nylon salt solution of homogeneous pH value provides reliable starting material to produce different polyamide products.This is considerably improved The reliability of polymerization product.In general, polymerization technique includes from nylon salt solution evaporation water to concentrate nylon salt solution and make The nylon salt of concentration is polymerize to form polyamide product by polycondensation.One or more evaporators can be used in the technique 202.The evaporation of water can carry out under vacuum or pressurization, to remove at least 75% of the water in nylon salt solution, more preferable nylon salt At least 95% of water in solution.The nylon salt 203 of concentration can include the water of 0-20wt.%.Polycondensation can be in batch technology or continuous It is carried out in technique.According to required final polymeric articles, additional AA and/or HMD can be added in into polymer reactor 204. In some embodiments, additive can be combined with polyamide product.

In order to achieve the object of the present invention, at least 85% carbochain that suitable polyamide product can be between amide group is Aliphatic.

When nylon salt solution is transferred to evaporator 202 by holding vessel 195, temperature is maintained at more than its fusing point.This It can be to avoid obstruction pipeline.In some embodiments, the steam obtained from evaporator 202 can be used for maintaining temperature.At other In embodiment, it is possible to use the cooling water of heating.

Polymerization can carry out in single-stage reactor or multi-stage polycondensation reactor 204.Additional monomer, AA or HMD, but preferably HMD can be added in by pipeline 205, to produce different nylon products 208.Reactor 204 can include to mix nylon salt Blender.Reactor 204 can have chuck, and temperature is adjusted using heat exchange medium.Polycondensation reaction in reactor 204 can be It is carried out in inert atmosphere, nitrogen can be added in into reactor 204.According to the dicarboxylic acids and diamines of starting, polymerization temperature can become Change, but usually above the melting temperature of nylon salt, more preferably higher than at least 10 DEG C of melting temperature.For example, include hexa-methylene two The melting temperature of the nylon salt of amine adipate is 165-190 DEG C.Therefore, polycondensation reaction can be at 165-350 DEG C, such as 190-300 DEG C temperature of reactor under carry out.Polycondensation reaction can carry out under atmospheric pressure or pressured atmosphere.Nylon product 208 can be free The form of the solid product of flowing is taken out from reactor.

The water generated in polycondensation reaction can be removed in a manner of steam stream by reactor draft tube liner 209.Steam Stream can be condensed, and gaseous monomer, such as diamines escaped together with water can be returned to reactor.

Subsequent processing can also be carried out, such as extrusion, spinning, stretching or stretcher strain, to produce polyamide product.Polyamides Amine product can be selected from and is 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 nylon 6/6,6.

The technique that following non-limiting embodiment describes the present invention.

Embodiment

Embodiment 1

Using mechanical conveying system（That is screw rod/haulage chain）Or pneumatic conveyer system（Forced air, evacuated air or close Ring nitrogen）By container bag discharging, the discharging of liner container bag, the discharging of liner box container or hopper railcar discharge terminal by AA powder Supply storehouse is moved to from discharge system.

Required AA powder is moved into weight-loss type by supply container（L-I-W）Dispenser uses PLC to be based on selected L-I- The low level and a high position of W hoppers are adjusted.Storehouse is supplied by screw transporter or swinging feeder with enough loading speed Rate measures AA powder, and enough loading speeds to be equal in largest interval, and preferably smaller than from a high position to low level L-I-W The half filling L-I-W dispenser hoppers of the minimum L-I-W discharge times in storehouse, in order to receive at least 67% time To the feedback signal of L-I-W dispenser feed rates.

L-I-W feed systems adjust the rate of L-I-W feed screws, as detected by L-I-W feed hopper pressure measuring units, Maintaining feed rate from scattered control system（DCS）The feed rate target received.

As shown in figure 11, by the feed rate variability of the adipic acid of loss in weight feeder, in the continuous feed cycle of 48h The interior feed rate variability having less than ± 5%.As shown in figure 12, within the cycle of 40h, the variability of feed rate can be less than ± 3%.As shown in figure 13, within the cycle of 18h, the variability of feed rate can be less than ± 1%.By eliminate due to the use of positive displacement to The disturbance of adipic acid feed rate caused by glassware, the charging that can be improved using the loss in weight feeder for adipic acid Rate variability performance.

Embodiment 2

Model is established to produce nylon salt solution according to continuous processing.The nylon salt solution includes water and hexa-methylene two Amine adipate.The model is set, to reach 63% salinity in nylon salt solution and obtain 7.500 target ph.Base The feed rate of AA is determined in the production of required nylon salt solution.Based on institute's salinity to be achieved and pH value, it may be determined that The feed rate of HMD and water.Adipic acid moves to weight-loss type charging with low variability as described in Example 1 from powder discharge system Device.

AA powder from loss in weight feeder directly feeds continuous stirred tank reactor, the charging conduit by charging conduit It is nitrogen with 20-30nm³The rate of/h sprays continuously to clean the steam skewed slot generated in feeding machine and reactor.

Utilize the object library storage stored based on salt feed rate and salt from salt reactor continuous stirred tank reactor DCS models, determine the DCS set-points of weight-loss type adipic acid charging rate.The feed rate of the salt can pass through Coriolis Mass flow meter measurement, and it indirect based on inventory model can set interval adjustment using adipic acid feed rate To desired value.Typically, adipic acid feed rate can directly make with together with the feed rate of loss in weight feeder for feeding back to DCS With.

The HMD storage recycling manifold that the HMD solution that concentration is 98% is controlled from pressure supplies online static mixer. Using the coriolis mass flow meter measurement that input is provided to DCS, DCS is adjusted into static state using the ratio control circuit that feedovers The feed rate of the HMD feeding flows of mixer is added to continuous stirred tank so as to accurately control based on AA powder feed rates HMD in reactor.This main HMD charging accounts for HMD needed for technique is fed about 95%.

The setting of DCS HMD ratio flow governors is adjusted by being used to supplement the backfeed loop of HMD valves output control Point, to maintain the output of supplement HMD valves as middle-grade, so as to ensure that the valve is located successively in controlled range.

Deionized water supplies online static mixing device from pressure control deionized water supply main.It is defeated using being provided to DCS The coriolis mass flow meter measurement entered, DCS feed the deionization of static mixer using the ratio control circuit adjustment that feedovers Water feed fluid flow rate, to accurately control the water concentration of AA and HMD in continuous stirred tank reactor.Deionized water into Material rate is set in dcs, so that deionized water enters the vent condenser of reactor with required charge velocity.

Online static mixing device product stream is directly entered the top of the CSTR at 0.3-1.0 meters of adipic acid feed well, This specific position is conducive to help the dissolving of the adipic acid entered charging.

It is recirculated back to using the sample of after the filtering of the recirculation pump offer by reactor, temperature and flowing control The pH meter of redundancy in road continuously pH value determination.Utilize DCS a pair of of the on-line pH value measurement results constantly compared selected PH value inputs, and DCS adjustment supplements the feed rate of HMD to maintain the target set point of pH value in dcs.Supplement HMD chargings about For 5% of total HMD chargings in technique.

Using what is carried out in the discrete interval of reactor downstream, and condition is made for 9.5% concentration and 25 DEG C so as to reach For the sample pH analysis or anti-by coming from constantly dilution/adjustment of the most sensitive of acid/amine balance of the function of pH value Answer the product of device or from subsequent storage container（If preferably）Product to 9.5% concentration and 25 DEG C of on-line analysis The continuous input of the pH value of instrument, the set-point based on statistical algorithms adjustment pH value controller.

By in the pumping for supplementing the HMD recirculation circuits that are injected into main reactor, during reaching the fastest response to pH meter Between and ensure that reactor product is adjusted to target within the shortest time.It pumps for HMD and reactor product salt to be mixed, In order to ensure that pH meter and densimeter are homogeneous phase solution when measuring respectively.

CSTR includes reactor chamber and recirculation circuit.Recirculation circuit includes a part of nylon salt solution being recycled to instead It answers the first circuit of device and by a part of nylon salt solution guiding value pH meter, is then return to the sample line of reactor.Sample Pipeline can include cooler, by nylon salt solution from its outflow reactor when temperature cool down about 5-10 DEG C.Continuously measure The pH value of the nylon salt solution of cooling.Nylon salt solution after cooling is back to reactor.The measurement feedback of pH value is given Technology controlling and process calculator, and adjust model.The model is adjusted the feed rate of HMD.

A part of nylon salt solution is offline, then by this portions of nylon salting liquid pH value determination in laboratory conditions. For the nylon salt solution measured in laboratory conditions, it is about 9.5% that nylon salt solution is diluted with water to concentration.Pass through perseverance Diluted nylon salt solution is cooled to about 25 DEG C by Wen Chi.The pH value of nylon salt solution, and and mesh are measured in laboratory conditions Mark pH value and on-line pH value measurement result compare.Then model is adjusted to provide the low variability that can ensure compared with target ph HMD feed rate.

The sample same spline filter, that temperature and flowing are controllable provided using the recirculation pump by reactor is recirculated back to The refractometer of redundancy in road continuously measures the concentration in reactor.The a pair constantly compared selected using DCS is online dense The concentration input of measurement result is spent, DCS adjusts the set-point of DCS deionized water ratio flow controllers to tie up by backfeed loop Hold the target set point of concentration in dcs.

Reactor product is continually fed at salt storage by the water level control in reactor.This transmission is included at least One group of filter cartridge type filter being arranged in parallel is up to have when flowing to the maximum instantaneous salting liquid transfer rate at storage 34.5kPa（5 pounds/square inch）Initial cleanness pressure drop and design.When use synthetic fibers depth filter core or fold membrane filter When, filter core excludes efficiency with minimum 10 μm of absolute nominal value or when using winding cotton fiber filter core, has minimum 1 μm of rated value.Filter core of the selection of filter based on the rated value with the operation temperature for minimum 110 DEG C.

Constantly recirculated through salt holding vessel, it is preferable to use the tanks for being arranged at 0.5-1 meters from tank bottom to mix nylon salt solution Injector is closed, for most changing soon so that mixing efficiency maximizes for tank concentration.

For 63% salinity, the temperature of salt holding vessel is by adjusting flowing through the steam stream of recirculation line heat exchanger It moves rate and controls at 100-105 DEG C.Nylon salt solution in holding vessel has 7.500 ± 0.0135 homogeneous pH value.

Embodiment 3

As prepared nylon salt solution in embodiment 2, the difference is that carrying out online pH measure in laboratory conditions： At about 25 DEG C, concentration about 9.5%.

Comparative example A

Imitate such as the model and technique in embodiment 2, the difference is that using volumetric feeder rather than weight-loss type into Glassware.Since the variation of AA powder feeds is very big, model is unpractical.The pH value of nylon salt solution deviates target ph Change more than 0.120.Thus, the modified crystallization temperature of nylon salt solution and boiling temperature.Therefore, the controllability of pH value Difference causes significantly higher solidification point, so as to need danger of the higher processing temperature with pre- crystallization-preventive.Due to the boiling point of variation, The controlling of this difference also causes nylon salt solution to be seethed with excitement, therefore reduces the yield of nylon salt solution.

Comparative example B

It imitates such as the model and technique in embodiment 2, is to use second CSTR without part.Nylon salt solution is from It is taken out in one CSTR, and feeds second CSTR.Nylon salt solution is measured between first CSTR and second CSTR PH value.According to pH value and target ph, additional HMA and/or water are added in second CSTR.From second CSTR transfer Nylon salt solution is removed, and measures its pH value.PH value deviates 0.120 pH value unit of target ph and changes.It needs additional CSTR is further to adjust the pH value of the nylon salt solution, so as to cause the increase of investment cost and operating cost.

Although to the present invention have been described in detail, revision within the scope and spirit of this invention is to art technology Personnel are obvious.All publications and document discussed above are introduced into herein by reference.This Outside, it should be understood that the aspect of the recorded present invention can be wholly or partly with multiple embodiments and multiple features It is combined or exchanges.In foregoing multiple embodiments, those of skill in the art would recognize that referring to other embodiments These embodiments can be with other embodiment appropriate combinations.Further, those skilled in the art will appreciate foregoing says It is bright to be only used for explaining the present invention by embodiment, do not form any limitation of the invention.

Claims

1. it is a kind of for producing the continuation method of nylon salt solution, including：

A) by based on dicarboxylic acid powder of the weight metering from loss in weight feeder to feed pipe and control dicarboxylic acid powder into Expect the variability of rate, dicarboxylic acid powder is transferred in single continuous stirred tank reactor by the feed pipe；

B) aqueous solution comprising diamines is independently introduced into the single continuous stirred tank reactor to form nylon salt solution； And

C) nylon salt solution from single continuous stirred tank reactor is continuously taken out and be introduced directly into holding vessel, wherein institute The pH value deviation target ph for stating nylon salt solution is less than ± 0.04 and changes, and the nylon salt solution includes 50- The salinity of 65wt.%；

Diamines is wherein supplemented to add in the upstream that pH is measured.

2. according to the method described in claim 1, wherein, the feed rate variability of dicarboxylic acid powder is less than ± 5%.

3. according to the method described in claim 1, wherein, target ph is selected from the scope of 7.200-7.900.

4. according to the method described in claim 1, wherein, the pH value of the nylon salt solution deviates target ph and is less than ± 0.03 And change.

5. according to the method described in claim 1, wherein, step b) further comprises supplement diamines charging being introduced continuously into list In the recirculation circuit of a continuous stirred tank reactor.

6. according to the method described in claim 1, wherein, aqueous solution is introduced in the position of the feed points of neighbouring feed pipe, with Just partly dissolving is fed to the dicarboxylic acid powder in single continuous stirred tank reactor.

7. according to the method described in claim 1, wherein, aqueous solution includes the diamines of 20-55wt.%.

8. according to the method described in claim 1, wherein, aqueous solution includes the water of 45-80wt.%.

9. according to the method described in claim 1, wherein, nylon salt solution includes the salinity of 60-65wt.%.

10. according to the method described in claim 1, wherein, single continuous stirred tank reactor is kept under an inert atmosphere.

11. according to the method described in claim 1, wherein, the method is further included before holding vessel using one or Multiple filters purify nylon salt solution.

12. according to the method described in claim 1, wherein, single continuous stirred tank reactor is maintained to 60-110 DEG C of temperature Under degree and normal pressure.

13. according to the method described in claim 1, wherein, the dicarboxylic acids is selected from by ethanedioic acid, malonic acid, succinic acid, penta 2 Acid, pimelic acid, adipic acid, suberic acid, azelaic acid, decanedioic acid, heneicosanedioic acid, dodecanedioic acid, maleic acid, glutaconate, Traumatic acid, muconic acid, 1,2- or 1,3- cyclohexyls dicarboxylic acids, 1,2- or 1,3- Asias phenylenediacetic Acid, isophthalic Dioctyl phthalate, terephthalic acid (TPA), 4,4 '-oxydibenzoic acid, 4,4- benzophenone bases dicarboxylic acids, 2,6- naphthalenes dicarboxylic acids, p-t- The group of butyl M-phthalic acid and 2,5- furan dicarboxylic acid and its mixture composition.

14. according to the method for claim 13, wherein, 1, the 2- or 1,3- cyclohexyl dicarboxylic acids are 1,2- or 1,3- Cyclohexyl oxalic acid.

15. according to the method described in claim 1, wherein, the diamines be selected from by ethanoldiamine, trimethylene diamine, putrescine, Cadaverine, hexamethylene diamine, 2- methyl-five methylene diamine, heptamethylene diamines, 2- methyl-hexamethylene diamine, 3- first Base-hexamethylene diamine ,-penta methylene diamine of 2,2- dimethyl, eight methylene diamines, 2,5- dimethyl-hexamethylene diamine, Nine methylene diamines, 2,2,4- trimethyls-hexamethylene diamine, 2,4,4- trimethyls-hexamethylene diamine, decamethylene two Amine, 5- methylnonanes diamines, isophorone diamine, 11 methylene diamines, ten dimethylene diamines, 2,2,7,7- tetramethyls- Eight methylene diamines, double (p- aminocyclohexyl) methane, double (aminomethyl) norbornanes, optionally by one or more C₁-C₄ Alkyl-substituted C₂-C₁₆The group of aliphatic diamine, aliphatic poly ether diamine and furans diamines and its mixture composition.

16. according to the method for claim 15, wherein, the furans diamines is double (aminomethyl) furans of 2,5-.

17. according to the method described in claim 1, wherein, the dicarboxylic acids is adipic acid, the diamines is hexa-methylene two Amine, the nylon salt solution include hexamethylene diamine adipate.