CN203829987U

CN203829987U - Processing device used for producing nylon salt solution

Info

Publication number: CN203829987U
Application number: CN201420172626.6U
Authority: CN
Inventors: 罗伯特·J·韦尔奇
Original assignee: Scientific & Technical Corp Of English Weida
Current assignee: Invista North America LLC
Priority date: 2013-05-01
Filing date: 2014-04-10
Publication date: 2014-09-17
Anticipated expiration: 2024-04-10
Also published as: TWM493411U

Abstract

The utility model discloses a processing device used for producing a nylon salt solution. The processing device comprises: a, a weightlessness type feeder which comprises a hopper, a feeding pipeline and a guide pipe used for connecting the hopper with the feeding pipeline; b, a direct insertion type disperser which comprises a first inlet connected with the outlet of the feeding pipeline and a second inlet used for leading in a second feeding flow of diamine to form a dispersion body, and a dispersion body outlet; c, a storage tank used for storing the dispersion body at a temperature between 50 DEG C and 60 DEG C, wherein the storage tank comprises a recirculation loop connected with the dispersion body outlet to receive the dispersion body; d, a single continuous stirred tank reactor used for receiving a portion of the stored dispersion body and a second feeding flow of the diamine so as to produce the nylon salt solution.

Description

For the production of the process unit of nylon salt solution

the cross reference of association request

The application requires to enjoy in the priority of U. S. application 61/818,057 of submitting on May 1st, 2013, the full content of described application and disclose incorporated herein.

Technical field

The utility model relates to the process unit for the production of nylon salt solution, relates in particular to comprise weight-loss type feeder and for the production of the process unit of direct insertion disperser of partial equilibrium acid solution that is rich in dicarboxylic acids.

Background technology

Polyamide is generally used for textile, clothes, packaging, tire enhancing, woollen blanket, engineering thermoplasties, electrical equipment, athletic equipment for the profiled part of automobile, and commercial Application widely.Nylon is a kind of high performance material, and it can be used in the plastics and fiber applications of the superpower durability of requirement, heat resistance and toughness.The fatty polyamide that is called as nylon can be produced and obtain from the salting liquid of dicarboxylic acids and diamines.Evaporate described salting liquid, be then heated with initiated polymerization.A challenge in this production technology is to ensure in final polyamide, and the mol balance of dicarboxylic acids and diamines is consistent.For example, when producing nylon 6 from adipic acid (adipic acid, AA) and hexamethylene diamine (hexamethylene diamine, HMD), 6 o'clock, inconsistent mol balance can adversely reduce molecular weight and may affect the dyeability of nylon.Batch salt method of use has realized mol balance, produces but a batch method is not suitable for large scale industry.In addition, realized mol balance by multiple reactors under continuous mode, at salt production period, each reactor is with diamines feed arrangement independently.

United States Patent (USP) discloses 2010/0168375 and has instructed the salting liquid of preparing diamines and diacid, more specifically, instructed the concentrated solution of having prepared a kind of adipic acid hexamethylenediamine salt, it is the useful initiation material for the production of polyamide, more specifically, it is the useful initiation material of producing PA66.Described salting liquid is to make by mixing diacid and diacid, the mass concentration of salt is 50% to 80%, in first step, provide and there is diacid/diamine mol ratio and be greater than 1.1 diacid and the aqueous solution of diamines, and in second step, regulate diacid/diamine mol ratio to the value of 0.9-11 by adding diamines, the preferably value of 0.99-1.01, and revise the mass concentration of described salt by optionally adding wherein water.Similarly, United States Patent (USP) discloses 2012/0046439 and has instructed and prepare salting liquid through multiple steps with two kinds of different diacid.

United States Patent (USP) 4442260 has been instructed a kind of method of the nylon salt solution for the manufacture of high concentration, wherein, diamines adds with two parts, a part added before the step that water is evaporated from the solution of maxima solubility, and another part adding after the step that water is evaporated from the solution of maxima solubility.

United States Patent (USP) 4213884 has been instructed the high concentration solution of salt and the method for nylon precondensate by the alkyl dicarboxylic aid of 6-12 carbon atom and diamine reactant being manufactured to dicarboxylic acids and diamines.The aqueous solution of the dicarboxylic acids of low concentration that contains the excessive special dicarboxylic acids of appropriate dissolving and the salt of diamines is reacted with the special diamines under molten state, under described special molten state, diamines is identical with the amount of the dicarboxylic acids of dissolving, described reaction is carried out under the condition of super-atmospheric pressure, and end reaction temperature is remained between 140 DEG C to 210 DEG C.By the solution obtaining for the manufacture of nylon.

United States Patent (USP) 4131712 has been instructed a kind of method of manufacturing superpolyamide, wherein, recently prepare respectively the component that is rich in diacid and the component that is rich in diamines with non-stoichiometry, under the fusion temperature lower than polyamide product, preferably, lower than 200 DEG C, melt each in these components; At sufficiently high temperature, the described component that is rich in diacid is contacted with liquid condition with the component that is rich in diamines subsequently, solidify preventing, and contact in proportional mode, the total amount that so makes diacid and diamines is as much as possible for stoichiometric, no matter its whether combination.

As the additive method of United States Patent (USP) 5801278 and 5674974, WO99/61510 and EP0411790 seeks to manufacture anhydrous nylon salt solution.Observe, method complicated and consuming time may reduce throughput rate and limit its application in the industrial production of nylon salt solution.For example, United States Patent (USP) 6995233 has been described a kind of continuation method for the manufacture of polyamide.Described polyamide is from diacid and diamines and obtain.Described method comprises the operation that continuous mixing is rich in amine-terminated compound and is rich in the compound of acid end group, and uses the polycondensation operation of described mixture.The method relates to the initial period of this technique, during this initial period, uses the aqueous solution that contains essence and become the mixture of the monomer of stoichiometric proportion.The described mixture that forms precursor can be the anhydrous water up to 10 quality % that maybe can contain.

Although made effort improving technique aspect realize target specification, for example, in nylon salt solution, aspect suitable pH value, mol balance and/or salinity, still there is challenge.Especially dicarboxylic acids (being more specifically adipic acid) is a kind of powder with variable particle size, and this causes large variation and the poor flow behavior of unit weight.Use dicarboxylic acids powder to introduce another variable, it makes to be difficult to the homogeneity of realize target specification in continuous processing.Volume feeder for dicarboxylic acids powder has amplified this difficulty.

Therefore need to improve the homogeneity of controlling the nylon salt that uses dicarboxylic acids powder.

Utility model content

In first embodiment, the utility model relates to the process unit for the production of nylon salt solution, comprise weight-loss type feeder, described weight-loss type charger comprises hopper, feed pipe, for connecting the conduit of hopper and feed pipe, wherein hopper comprises at least one the external weights measuring system for controlling supplemental stages and charging stage, with at least one lower openings for distribute dicarboxylic acids powder in the charging stage, wherein said at least one lower openings is placed in feed pipe top, and wherein said feed pipe receives dicarboxylic acids powder, and dicarboxylic acids powder is passed through to export through at least one rotating screw transmission.Described process unit further comprises direct insertion disperser, described direct insertion disperser has the first import of the outlet that connects feed pipe, for the first feed stream of introducing diamines to form the second import of dispersion, and disperser outlet; Storage tank, for storing dispersion at the temperature between 50 DEG C and 60 DEG C, wherein storage tank comprises the recirculation circuit that connects dispersion outlet, to receive dispersion; Continuous stirred tank reactor, for receiving a part for dispersion and second feed stream of diamines of storage, to produce nylon salt solution.

In one embodiment, described recirculation circuit comprises the outside displacer receiving as the dispersion of guiding stream.On the one hand, recirculation circuit can comprise one or more pumps and one or more heater, receives dispersion in its downstream.Described recirculation circuit is not preferably connected to measure dispersion with any analyzer.Described recirculation circuit can be expelled to storage tank through one or more internal spray blenders.Described one or more internal spray blender is placed in between 0.3 and 1.5 meters of tank bottom and locates.

In one embodiment, direct insertion disperser comprises inner chamber and multiple inner chamber agitator around that is looped around, and described multiple inner chamber agitators around that are looped around are for mixing to form dispersion by the first feed stream of dicarboxylic acids powder and diamines.Described dispersion can be by discharging through multiple agitators of outlet.

In a detailed description of the invention, weight-loss type feeder can comprise transfer system, for dicarboxylic acids powder is transported to hopper from supply container.The conduit of weight-loss type feeder also can comprise rotary table feeder.

In second detailed description of the invention, described process unit comprises the weight-loss type feeder of the first import that is connected in direct insertion disperser.Direct insertion disperser further comprises that the first feed stream for introducing diamines exports with the second import and the disperser that form dispersion.Described process unit further comprise be connected in disperser export to receive dispersion recirculation circuit for storing the storage tank of dispersion, for receiving the part for dispersion of storage and the second feed stream of diamines to produce the single continuous stirred tank reactor of nylon salt solution, and for nylon salt solution is directly passed into the conduit that nylon salt storage tank goes from single continuous stirred tank reactor.The storage of PBA solution can be carried out at the temperature between 50 DEG C and 60 DEG C.

Brief description of the drawings

Understand better the utility model below in conjunction with nonrestrictive accompanying drawing, wherein:

Fig. 1 is the overview flow chart for the production of nylon salt solution according to an embodiment of the present utility model.

Fig. 2 be according to an embodiment of the present utility model for the production of being rich in the weight-loss type feeder of crude salt solution of adipic acid and the schematic diagram of direct insertion disperser.

Fig. 3 be according to an embodiment of the present utility model for the production of the profile of exemplary direct insertion disperser of crude salt solution that is rich in adipic acid.

Fig. 4 is according to the schematic diagram of the continuous stirred tank reactor of an embodiment of the present utility model.

Fig. 5 is according to the schematic diagram of the process control of an embodiment of the present utility model.

Fig. 6 is according to the schematic diagram of nylon 6,6 production technologies of an embodiment of the present utility model.

Fig. 7-9 are the chart from the feed-rate variation of the adipic acid of weight-loss type feeder according to the demonstration of an embodiment of the present utility model.

Detailed description of the invention

Term used herein only, for the object of describing particular, is not intended to limit the utility model.Unless clearly shown other situation in context, singulative " " and " being somebody's turn to do " also comprise plural form as used herein.It should also be understood that, the term using in this manual " comprises " and/or has illustrated when " including " and have described feature, entirety, step, operation, parts and/or member, but do not hinder existence or the interpolation of one or more other features, entirety, step, operation, parts group, member and/or member group.

For example " comprise ", term and the variant thereof of " comprising ", " having ", " containing " or " relating to " should understand widely, and comprises listed main body and equivalent, also has unlisted other main body.In addition, when " being comprised " by transitional term, " comprising " or " containing " while drawing component, parts group, technique or method step or any other statement, be to be understood that and also considered identical component, parts group, technique or method step herein, or there is any other statement of transitional term before the record of this component, parts group, technique or method step or any other statement " substantially by ... composition ", " by ... composition " or " choosing freely ... the group of formation ".

If applicable words, the device of corresponding structure, material, action and all functions in claim or the equivalent of step comprise that the miscellaneous part for specifically stating with claim carries out any structure, material or the action of function in combination.Description of the present utility model for introduce and describe object and provide, but be not exhaustive or the utility model is restricted to disclosed form.Do not departing under the prerequisite of scope and spirit of the present utility model, many changes and variant are apparent for the person of ordinary skill of the art.Here select and described some embodiments, object is that principle of the present utility model and practical application are carried out to best explanation, and other those of ordinary skill that make this area can be understood different embodiments of the present utility model and have multiple variation, as being suitable for this special-purpose.Correspondingly, although the utility model is described according to embodiment, but those skilled in the art will recognize that, the utility model can change to some extent ground and implement within the spirit and scope of claims.

Now with detailed reference to specific disclosed theme.Although disclosed theme is described in connection with cited claim, however be appreciated that they not by disclosed subject matter restricted in these claims.On the contrary, disclosed theme has covered all replacement schemes, change and equivalent, within these can be contained in the scope of disclosed theme defined by the claims.

introduction

The polyamide that the utility model relates generally to the production of nylon salt solution and produces from the nylon salt solution of dicarboxylic acids and diamines.Especially, the utility model relates to produces liquid part balance acid (PBA) solution that is rich in dicarboxylic acids, is called again rich sour charging, and it uses to form nylon salt solution as feedstock solution.Form nylon salt solution with realize target salinity and/or target pH value.PBA solution is partial balanced, and can not realize target pH value or the target salinity of nylon salt solution.In single continuous stirred tank reactor, PBA solution can be combined with the charging of another diamines and water to produce and be produced the nylon salt solution with homogeneous pH value with realize target.Advantageously, PBA solution can allow the dicarboxylic acids of liquid phase to introduce in single continuous stirred tank reactor.In one embodiment, have homogeneous pH value nylon salt solution polymerizable with form nylon 6,6.Can produce the polyamide of other kinds according to the initial monomers using.

As described below, use term adipic acid (AA) and hexamethylene diamine (HMD) to represent dicarboxylic acids and diamines.In the time using adipic acid, PBA solution is partial balanced solution of adipic acid.But this method can also be applied to other dicarboxylic acids noted here and other diamines.

Be applicable to the group of the freely following compound composition of dicarboxylic acids choosing of the present utility model: ethanedioic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, adipic acid, suberic acid, azelaic acid, decanedioic acid, heneicosanedioic acid, dodecanedioic acid, maleic acid, glutaconate, traumatic acid, muconic acid, 1, 2-cyclohexane dicarboxylic acid or 1, 3-cyclohexane dicarboxylic acid, 1, 2-phenylenediacetic Acid or 1, 3-phenylenediacetic Acid, 1, 2-cyclohexanediacetic or 1, 3-cyclohexanediacetic, M-phthalic acid, terephthalic acid (TPA), 4, 4 '-diphenyl ether dioctyl phthalate, 4, 4-benzophenone dicarboxylic acids, 2, 6-naphthalene dicarboxylic acids, the p-M-phthalic acid tert-butyl ester and 2, 5-furans dicarboxylic acids, and their mixture.In one embodiment, described dicarboxylic acid monomer comprises at least 80% adipic acid, for example, and at least 95% adipic acid.

For manufacturing nylon 6,6, the dicarboxylic acids that adipic acid (AA) is best suited for and using with powder type.AA can respective pure form obtain conventionally, and it contains the very impurity of low content.Typical impurity comprises other acid (monoacid and rudimentary binary acid), is less than 60ppm; Nitrogen substance; Trace metal, as iron (being less than 2ppm) and other heavy metals (lower than 10ppm or be less than 5ppm); Arsenic (being less than 3ppm); And hydrocarbon-type oil (be less than 10ppm or be less than 5ppm).

Be applicable to the group of the freely following compound composition of diamines choosing of the present utility model: ethanol diamines, propane diamine, butanediamine, cadaverine, hexamethylene diamine, 2 methyl pentamethylenediamine, heptamethylene diamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine, 2, 2-dimethyl-penten diamines, octamethylenediamine, 2, 5-dimethyl hexamethylene diamine, nonamethylene diamine, 2, 2, 4-trimethyl hexamethylene diamine and 2, 4, 4-trimethyl hexamethylene diamine, decamethylene diamine, 5-methyl nonamethylene diamine, IPD, 11 diamines, 12 diamines, 2, 2, 7, 7-tetramethyl octamethylenediamine, two (p-aminocyclohexyl) methane, two (amino methyl) norbornane, by the optional C replacing of the alkyl group of one or more C1-C4 ₂-C ₁₆aliphatic diamine, aliphatic polyether diamines and furans diamines, as 2,5-bis-(amino methyl) furans, and their mixture.Selected diamines can have the boiling point higher than dicarboxylic acids, and described diamines is not preferably m-xylene diamine.In one embodiment, described diamine monomer comprises at least 80% hexamethylene diamine, for example, and at least 95% hexamethylene diamine.Hexamethylene diamine (HMD) is most commonly used to prepare nylon 6,6.HMD solidifies at approximately 40 DEG C to 42 DEG C, conventionally adds water to reduce this fusing point and make to process to become easy.Therefore, HMD can be used as concentrated solution and buys, for example, and as from 80 % by weight to 100 % by weight or buy from the concentrated solution of 92 % by weight to 98 % by weight.

Except the polyamide based on dicarboxylic acids and diamines only, it is favourable being sometimes combined with other monomers.When the ratio to be less than 20 % by weight, as be less than 15 % by weight ratio add time, these monomers can join in nylon salt solution, and do not depart from scope of the present utility model.These monomers can comprise monofunctional carboxylic acids, as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, benzoic acid, caproic acid, enanthic acid, sad, n-nonanoic acid, capric acid, hendecanoic acid, laurate, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, Sa Fen acid (sapienic acid), stearic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, erucic acid etc.These monomers also can comprise lactams, as α-beta-lactam, α-azetidinone, azetidinone, butyrolactam, δ-valerolactam, γ-valerolactam, caprolactam etc.These monomers also can comprise lactone, as α-second lactone, α-propiolactone, beta-propiolactone, gamma-butyrolacton, δ-valerolactone, gamma-valerolactone, caprolactone etc.These monomers can comprise difunctional alcohol, as monoethylene glycol, diethylene glycol (DEG), 1,2-PD, 1, ammediol, DPG, 1,2-butanediol, 1,3-BDO, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, Rutgers 612 (etohexadiol), the p-Meng alkane-3,8-glycol, 2-methyl-2,4-pentanediol, 1,6-hexylene glycol, 1,7-heptandiol and 1,8-ethohexadiol.Also can use the molecule of more senior sense, as glycerine, trimethylolpropane, triethanolamine etc.Also can be selected from suitable azanol, such as monoethanolamine, diethanol amine, 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-butanols, amylalcohol amine, hexanol amine etc.Should be understood that the mixture that also can use any these monomers, and do not deviate from scope of the present utility model.

It is also favourable sometimes in polymerization technique that other additives are incorporated into.These additives can comprise heat stabilizer, as mantoquita, KI or any other antioxidant as known in the art.Such additive also can comprise polymerization catalyst, for example the slaine of metal oxide, acid compound, phosphorous oxide compound as known in the art or other compounds.Such additive can be also delustering agent and colouring agent, as titanium dioxide, and carbon black or other pigment as known in the art, dyes and dyestuffs.The additive using also can comprise defoamer, as silica dispersion, Organosiliconcopolymere or other defoamer as known in the art.Can use lubricating auxiliary agent, as zinc stearate, stearyl mustard acid amides, stearyl alcohol, aluminium distearate, ethylene bis stearamide or other polymeric lubricant as known in the art.In mixture, may comprise nucleator, as aerosil or aluminium oxide, molybdenum bisuphide, talcum, graphite, calcirm-fluoride, phenyl phosphinic acid salt or other auxiliary agent as known in the art.Also in polymerization process, add other common additives known in the art, as the filler of fire retardant, plasticizer, impact modifier and some type.

The utility model has advantageously been realized the nylon salt solution that comprises the AA/HMD salt with target pH value.Especially, compared with conventional method, the utility model uses the container of lesser amt to realize target pH value, especially, at single continuous stirred tank reactor (continuous stirred tank reactor, CSTR) in, realized target pH value, so that the nylon salt solution of homogeneous phase to be provided.In this application, prepare nylon salt solution with direct insertion disperser and single continuous stirred tank reactor, than a batch production, it can realize higher throughput rate.In batch production, make batch production infeasible for realizing with the time of equipment and the quantity of fund cost of producing continuously the akin productivity ratio of attainable productivity ratio.Target pH value can be any pH value that those skilled in the art select, and can select by the final polymeric articles based on needs.Without being limited by theory, desired value can be selected from the highest flex point slope of pH curve, and the region the best of level in to(for) the polymeric articles of wanting.

In some exemplary embodiments, the target pH value of nylon salt solution can be the value in the scope between 7.200 and 7.900, as preferably between 7.400 and 7.700.The actual pH of nylon salt solution with respect to the variation of the target pH value of nylon salt solution can be less than ± 0.04, more preferably less than ± 0.03, be most preferably less than ± 0.015.Therefore, if for example target pH value is 7.500, the pH value of nylon salt solution is between 7.460 and 7.540 so, more preferably between 7.470 and 7.530.For the purpose of this utility model, the rate of change of pH value refers to the average rate of change of continued operation.This rate of change is very low, be less than ± 0.53%, more preferably less than ± 0.4%, and produce the nylon salt solution that has homogeneous pH value.There is the reliability that is conducive to improve polymerization process with respect to the nylon salt solution of the homogeneous of the low rate of change of target pH value, to produce the polymeric articles of homogeneous phase, high-quality.The nylon salt solution with homogeneous pH value also can allow the charging of stabilised quality can enter polymerization process.Target pH value can change according to manufacturing location.Generally, the pH value of for example measuring 9.5% salinity at 25 DEG C is 7.620, produces and has the nylon salt solution that AA is 1 than the mol ratio of HMD, AA and the HMD of described mol ratio based on free and chemical bonding.For the purpose of this utility model, according to target pH value, described mol ratio can change in the scope of 0.8-1.2.There is homogeneous pH value and also mean that the mol ratio of nylon salt solution has corresponding low rate of change.

Except target pH value, the utility model also can realize target salinity.Described target salinity can be any salinity that those skilled in the art select, and can final polymeric articles and storage based on needs consider to select.The water concentration of nylon salt solution can be between 35 % by weight and 50 % by weight.Nylon salt solution can have the salinity between 50 % by weight and 65 % by weight, for example, and between 60 % by weight and 65 % by weight.The rate of change of the salinity of nylon salt solution is preferably very low, for example with respect to target salinity be less than ± 0.5%, be less than ± 0.3% or be less than ± 0.1%.For the purpose of this utility model, the rate of change of salinity refers to the mean change of continued operation.Therefore, for example, if target salinity is 60%, the nylon salt concentration of homogeneous has the salinity between 59.5 % by weight and 60.5 % by weight so, preferably there is the salinity between 59.7 % by weight and 60.3 % by weight, more preferably there is the salinity between 59.9 % by weight and 60.1 % by weight.Target salinity can change according to manufacturing location.

Nylon salt solution can be used as liquid and stores under the temperature lower than 110 DEG C and atmospheric pressure, for example, at the temperature between 60 DEG C and 110 DEG C, or at the temperature between 100 DEG C and 105 DEG C.The temperature higher higher than the concentration requirement of 65 % by weight also may need pressurization, to keep nylon salt solution as liquid, and for example homogeneous liquid.Described salinity can affect storing temperature, and generally, can effectively store nylon salt solution in lower temperature and under normal pressure.But, before carrying out polymerization, lower salinity can things turn out contrary to one's wishes ground increase energy and consume to concentrate described nylon salt solution.

The utility model is introduced nylon salt solution with PBA solution by AA, and PBA solution can not realized target pH value or the target salinity of nylon salt solution.Preferably the full dose of AA required nylon salt solution is introduced to PBA solution,, to realize the low rate of change of being less than of AA concentration ± 5%, for example, be preferably less than ± 2%, be less than ± 1% or be less than ± 0.5%.

Be not subject to AA to control independently the temperature of nylon salt solution than the impact of the mol ratio of HMD.Although the mol ratio in nylon salt solution and the concentration of solid can affect the temperature of nylon salt solution, described method depends on heat exchanger, coil pipe and/or the CSTR with chuck and from process, removes heat, controls thus the temperature of nylon salt solution.The temperature that can control nylon salt solution than temperature required being less than ± change in the scope of 1 DEG C.At the boiling point lower than nylon salt solution but select the temperature of nylon salt solution higher than crystallization temperature.For example, the nylon salt solution that solid concentration is 63% under atmospheric pressure has the boiling point of 108 DEG C to 110 DEG C.Therefore, temperature is controlled at and is less than 110 DEG C, as be less than 108 DEG C, but higher than crystallization temperature.

The prior art scheme that realizes the low rate of change of nylon salt concentrates on the mol ratio and the HMD concentration that regulate the AA:HMD in salting liquid with multiple reactors.This concentrates the variability of unit weight and the mobility of difference due to AA powder at least in part, causes the unpredictability of intrinsic AA powder feed.When with volume feeder, AA powder feed during to reactor, having been expanded to the variability of AA powder unit weight.Due to the high-melting-point of AA, conventionally provide AA with powder, this has increased the difficulty of processing AA.In order to reduce the difficulty of processing AA powder, the utility model has formed the liquid PBA solution that comprises AA.By AA powder is combined to prepare PBA solution with liquid diamines.AA powder has the average-size between 75 and 500 microns conventionally, between 100 and 300 microns.More tiny powder has substantially larger surface area and contacts with particle, and this has caused caking.Preferably, AA powder contains the particulate that is less than 75 microns that is less than 20%, for example, be less than 10%.Due to conventionally, based on volume, directly pass in reactor and measure AA powder with powder morphology, the variation of powder size can affect bulk packages (bulk packing) and the density of the AA powder being fed in nylon salt reactor.The variation of these bulk packages and density can cause pH value in nylon salt solution and AA than the variation of the mol ratio of HMD subsequently.Consider this variation, the solution of prior art is to arrange nylon salt tandem reactor.For example, disclose 2012/0046439 and 2010/0168375 referring to United States Patent (USP).This traditional method use the measuring method of goal standard and by monomer feed to serial reaction device.But this method requires multiple reactors, measuring method and control method, this can increase cost limit production rate.In addition, this conventional method may be more suitable in batch production instead of produce continuously.Finally, these conventional methods can not use a model to predict pH value and/or salinity, thereby constantly regulate and make nylon salt solution reach goal standard.

Effect with the distribution that is fed to particle size that AA powder in nylon salt technique is relevant and particle size is solution in the prior art by add AA and HMD with multiple reactors.Have been found that by measure AA powder based on weight, instead of measure with volume, can greatly reduce the variability of AA powder feed rate.In some aspects, AA powder feed rate can change in the scope that is being less than ± 5% compared with target AA powder feed rate, be for example less than ± 3% or be less than ± 1%.Use this stable charging, method of the present disclosure can be used a single-reactor, and need not multiple tandem reactors, forms the nylon salt solution of goal standard.Because the ability that regulates monomer exists restriction, therefore, being difficult to is not having stable AA powder feed and controlling the rate of change of nylon salt solution than target pH value and target salinity with single reactor under high continuous throughput rate.The stable charging with AA powder makes described method can control to utilize the feed forward rate of HMD, and makes it possible to regulate compensation HMD to regulate pH value to carry out realize target pH value.Advantageously, the specific embodiments of imagination, by the quantity of the unit operations in minimizing method, provides than existing open simple designs more.Therefore, this disclosed method is considered to essential step before having omitted.This has reduced floor space and the fund cost of equipment.The nylon salt solution obtaining can carry out polymerization subsequently to form required polyamide.

The acceptable production of manufacturing in order to realize the industry of nylon salt, can produce nylon salt solution by the continuous method of PBA solution.Batch production will require significantly larger container and reactor.Further, described batch of production can not realize accessible throughput rate by less continuous producing apparatus.In polymerization, be favourable to have that the pH value of homogeneous and the nylon salt solution of salinity starts.Slight variation can cause the production quality problem in polymerization, and this needs the adjustment of extra monitoring, control and polymer process.

Fig. 1 provides one according to the general overview figure of the method for the production nylon salt solution of embodiment of the present utility model.As shown in Figure 1, nylon salt productive method of solution 100 comprises AA powder 102 is fed to weight-loss type feeder 110, and the AA powder feed 139 of its measure of production also directly passes into direct insertion disperser 170.Water and HMD also enter direct insertion disperser 170 to form the PBA solution 172 that is rich in AA through pipeline 103 and 104 respectively, also can be described as feedstock solution.In one embodiment, PBA solution 172 has AA between 2:1 and 5:1 than the mol ratio of HMD, and for example, between 2:1 and 3:1, described AA is AA and the HMD based on free and chemical bonding than the mol ratio of HMD.It is liquid keeping PBA solution 172, and does not form slurry or solid.By using liquid PBA solution 172, AA powder 102 directly need not be introduced (continuous stirred tank reactor, CSTR) in continuous stirred tank reactor 140.As further described below, before being introduced in continuous stirred tank reactor 140, PBA solution 172 can be able to be stored in tank 184.Can allow so more mixing, allow, the stock who forms the AA storing before nylon salt solution, also to allow to produce independently PBA solution and nylon salt solution.In addition, water is by pipeline 103 ', and HMD is fed in continuous stirred tank reactor 140 by pipeline 104 '.In some embodiments, before being fed to reactor 140, pipeline 103 ' and 104 ' can be merged to (not shown).

From reactor 140, withdraw from the liquid that contains nylon salt solution by recirculation circuit 141, and be back to reactor 140.Before analyzing pH value or salinity, can add extra HMD in crosspoint 142 from pipeline 107, referred to herein as compensation HMD, to regulate the pH value of nylon salt.Withdraw from nylon salt solution from recirculation circuit in crosspoint 143, and enter pipeline 144.Nylon salt solution process filter 190 in pipeline 144 is to remove impurity and to be collected in storage tank 195.Similar to PBA solution 172, the nylon salt solution in storage tank 195 can not form slurry or solid.Conventionally, these impurity can comprise corroding metal, and can comprise coming the impurity of the monomer feed of AA powder 102 freely.Nylon salt solution is moved in polymerization technique 200 through pipeline 199.Nylon salt solution can be stored in storage tank 195, until need to be used for polymerization.In some embodiments, described storage tank 195 is transportable.

nylon saline solution means

In one embodiment, the utility model relates to the continuation method for the production of nylon salt solution, comprise: by weight, measure the dicarboxylic acids powder from weight-loss type feeder to feed conduit, described feed conduit can be delivered to dicarboxylic acids powder direct insertion disperser; The first feed stream of diamines is passed in direct insertion disperser, to form the diamines between dicarboxylic acids, 11 % by weight and 15 % by weight that contain between 32 % by weight and 46 % by weight, and dispersion between 39 % by weight and 57 % by weight water; At the temperature between 50 DEG C and 60 DEG C, heat described dispersion, to form PBA solution; The second feed stream of PBA solution and diamines is introduced to continuous stirred tank reactor, to form nylon salt solution; From continuous stirred tank reactor, withdraw from continuously nylon salt solution and directly pass in storage tank, wherein the salinity of nylon salt solution is 50-65 % by weight and comprises the dicarboxylic acids/diamine salts with target pH value; And control the feed-rate variation rate of dicarboxylic acids powder, make target pH variation in the scope of ± 0.04pH.Preferably, method of the present utility model allows PBA solution to have to be less than ± low rate of change of 5% concentration of adipic acid, be for example preferably less than ± 2%, be less than ± 1% or be less than ± 0.5%.

aA powder feeder based on weight

Fig. 2 provides the further details of producing the PBA solution 172 that is rich in AA.Use weight-loss type feeder 110 that AA powder 102 is fed in direct insertion disperser 170.Weight-loss type feeder 110 is measured AA powder 102 and is had the AA powder feed logistics 139 of low variational feed rate to produce, and can cause the variation of the density of AA powder 102 in fill process.As implied above, the unit weight of AA powder 102 and mobility may alter a great deal, and cause introducing the uneven of molar ratio and produce the nylon salt solution of inhomogenous pH value.The utility model is with respect to not realizing the volume feeder of the low variability feed rate of AA powder or the feeder of other types is favourable.For the purpose of this utility model, the low variability feed rate of AA powder be the target feed speed of AA powder ± 5% scope in, in the scope as ± 3%, in ± 2% scope, or ± 1% scope in.For the purpose of this utility model, the variability of feed rate refers to the average rate of change in continued operation.Due to the low variability of AA powder feed rate, the feed rate of AA is stable and predictable.The low rate of change of AA powder feed rate can allow the formation of the PBA solution that forms the concentration of adipic acid with low rate of change.Stable and predictable AA powder feed rate can allow to set suitably the feed rate of diamines and water, to make coming realize target pH value and/or target salinity with single reactor.Due to the low variability with respect to target feed speed AA powder feed rate, therefore do not need extra reactor mix and regulate.

Usually, weight-loss type feeder 110 operates to load hopper 111 in supplemental stages, the contents in charging stage distribution hopper 111.Preferably, at least 50% time, preferably, at least 67% time, this supplement-cycle charging stage is enough to accept the feedback signal from weight-loss type feeder 110.In one embodiment, the time of supplemental stages can be less than 20% (as the total time of charging and supplemental stages) of total cycle time, as be less than total cycle time 10% or be less than 5% of total cycle time.The time in supplemental stages and total cycle is depended on throughput rate.During the charging stage, the contents in hopper 111 are assigned to feed pipe 112, and described feed pipe 112 is delivered to AA powder in continuous stirred tank reactor 140 through pipeline 139.In addition, during supplemental stages, in hopper 111, remaining AA also can be assigned in feed pipe 112, and so feed pipe 112 receives the continuous supply of AA powder.Useful controller 113 is controlled weight-loss type feeder 110.Controller 113 can be distribution control system (distributed control system, DCS), or programmable logic controller (programmable logic controller, PLC), described programmable logic controller can carry out output function according to accepted input message.In one embodiment, can have multiple controllers, it is for the multiple assembly of system.For example, can regulate and control supplemental stages with PLC, and control the feed rate through feed pipe 112 according to the targeted rate arranging in DCS with DCS.

As shown in Figure 2, transfer system 114 is loaded into AA powder 102 in supply container 115.Transfer system 114 can be mechanical transmission system or pneumatic transfer system, and it transports the adipic acid from container bag, liner container bag, liner box container or hopper railcar depot.Mechanical transmission system can comprise screw rod and haulage chain.Pneumatic transfer system can comprise that closed conduit is with, evacuated air next with compressed air, or AA powder 102 is delivered to supply container 115 by the circulating nitrogen gas of sealing.In some embodiments, transfer system 114 can provide the functor that picks with in the time loading supply container 115, the caking of broken AA powder.Supply container 115 can be cylindrical shape, the shape that trapezoidal, square or other are suitable, and has import 116 at top.Contribute to assist AA powder 102 to flow out supply container 115 with the shape of hypotenuse.The top edge of supply container 115 can be lower than system ground elevation more than 130 20 meters (m), as preferably lower than 15m.System ground elevation 130 refers to the plane that is supporting the various device that is used for producing nylon salt solution thereon, and is commonly defined as and there is no the plane of monomer through it.System ground elevation can be on the import of CSTR.Because the height with respect to system ground elevation 130 of supply container 115 is lower, therefore need less energy to carry out driving transmission system 114 and load supply container 115.

Supply container 115 also has low valve 117, in the time that it is closed, forms one for holding the inner chamber of AA powder 102.Low valve 117 can or comprise feeder and the coupling apparatus of valve for rotary table feeder, feeding screw, rotary flow device.When inner cavity filled with AA powder 102, can keep low valve 117 to close.During supplemental stages, can open low valve 117, based on volume, AA powder 102 is sent to hopper 111.In the time that AA powder is sent to hopper 111 by low valve, AA powder can be loaded in supply container 115.Low valve 117 can comprise one or more ailerons that can form sealing in the time that low valve cuts out.In one embodiment, can there is conveyer belt (not shown), for AA powder 102 is delivered to hopper 111 from supply container 115.In other embodiments, supply container 115 can pass through gravity transfer AA powder 102.The loading of supply container 115 can be independent of the loading of hopper 111.

Supply container 115 can have the capacity that is greater than hopper 111, preferably has the capacity that at least doubles or be three times in hopper 111.The capacity of supply container 115 should be enough to supplement the whole volume of hopper 111.Compare hopper 111, AA powder 102 can hold the longer time in supply container 115, and according to humidity, AA powder 102 may form caking.Can carry out broken described caking by the mechanical circulator in supply container 115 bottoms or vibrator (not shown).

The top edge of hopper 111 can more than 130 be less than 15m at system ground elevation, as being preferably less than 12m.Hopper 111 can be cylindrical shape, the shape that trapezoidal, square or other are suitable, and has import 118 at top.Preferably, the inner surface of hopper is steep, to prevent the bridge joint of AA powder.In one embodiment, described inner surface has the angle of 30 ° to 80 °, for example the angle of 40 ° to 65 °.Described inner surface can be U-shaped or V-type.Hopper 111 also can have removable with porose cover plate (not shown), and described hole is for import 118 and ventilating opening.Hopper 111 can be installed on conduit 119, and hopper 111 is connected to feed conduit 112 by described conduit 119.In one embodiment, hopper 111 has equal volume to maintain the throughput rate of expectation.For example, hopper 111 can have the capacity of at least 4 tons.The maximum gauge of conduit 119 is less than the maximum gauge of hopper 111.As shown in the figure, conduit 119 has rotary table feeder 120 or similar conveying device, is used for the contents in hopper 111 to be dispensed to feed pipe 112 through outlet 129.Can under On/Off pattern, operate rotary table feeder 120, or the function that can be used as required feed rate is controlled the speed of rotation.In another embodiment, conduit 119 can not have inner feeding mechanism.According to the type of weight-loss type feeder, rotary table feeder 120 can be massaged oar by external or oscillator is replaced, and described external massage oar can be dispensed to feed pipe 112 from hopper 111 by discharge.Outlet 129 can have the caking of the next broken AA of mechanical system.In another embodiment, weight-loss type feeder 110 can have drier or dry gas purging device (not shown), to remove moisture from AA powder, to prevent that AA powder from luming and forming obstruction in hopper 111.

Weight measurement subsystem 121 is connected with hopper 111.Weight measurement subsystem 121 can comprise multiple sensors 122, and it is for weighing bucket 111 and provide the signal that represents weight to controller 113.In some embodiments, can there be three sensors or four sensors.Sensor 122 can be connected with the outside of hopper 111, and considers the initial weight of hopper 111 and any other equipment being connected with hopper 111, and described sensor 122 can taring.In another embodiment, sensor 122 can be placed in the below of hopper 111.Based on the signal from weight measurement subsystem 121, controller 113 is controlled supplemental stages and charging stage.The weight that controller 113 is relatively measured under conventional interval, to determine the weight of the AA powder 102 that is dispensed to feed conduit 112 within a period of time.Controller 113 is gone back the speed of rotation-controlled auger 123, is below describing.

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

Feed pipe 112 is placed in the below of conduit 119, and receives AA powder 102.In one embodiment, feed pipe 112 can be connected with conduit 119.The plane of the extensible outlet 129 that is basically perpendicular to conduit 119 of feed pipe 112, or can be extended out the angle between 0 ° and 45 ° from plane and to direct insertion disperser 170, as the angle between 5 ° and 40 °.Feed pipe 112 has at least one rotating screw 123, and it transmits AA powder 102 by opening and export 124, and enters reactor 140.Rotating screw 123 is driven by motor 125, and can comprise worm screw.Also can use twin worm structure.Motor 125 drives rotating screw 123 with the speed of fixing or change.In one embodiment, feed pipe 112 passes AA powder 102 is delivered in direct insertion disperser 170 with low variational speed.Can regulate according to the productive rate of expecting the feed rate of AA.This allows to set up fixing AA feed rate, and uses model described herein, changes subsequently the feed rate of other solution components to realize salinity and/or the pH desired value expected.Controller 113 receives the feedback signal from weight-loss type feeder 110, and regulates the speed of rotating screw 123.Controller 113 is the signal based on from weight measurement subsystem 121 also, regulates the feed rate of feed pipe 112.Can affect motor speed (as increased, keep or reduction motor speed) to realize the loss in weight of setting to the command signal of rotating screw brill 123.

In other embodiments, feed pipe 112 described herein can be any controllable type feeder being equal to, as belt feeder, van-type feeder, feed disk, oscillatory type feeder etc.Feed pipe 112 also can involving vibrations buffer (not shown).In addition, feed pipe 112 can have 1 or multiple gas port (not shown), for injecting nitrogen to remove oxygen.

Hopper 111 also can comprise high-order probe 127 and low level probe 128.It will be appreciated that, for object easily, shown a high position and a low level probe, but can have multiple probes.Described probe can be combined with weight measurement subsystem 121.For the purpose of this utility model, described probe can be level point indicating gage or capacitive proximity sensor.High-order probe 127 in adjustable hopper 111 and the position of low level probe 128.High-order probe 127 is positioned near the top of hopper 111.In the time measuring the material in hopper 111 by high-order probe 127, supplemental stages completes and starts the charging stage.On the contrary, low level probe 128 is positioned at the below of high-order probe 127, and the bottom of more close hopper 111.The position of low level probe 128 can make the AA powder 102 of enough surpluses to distribute in supplemental stages.There is no material in low level probe 128 detects hopper on its position time, start supplemental stages.As mentioned above, during supplemental stages, can continue charging.

AA solid can be corrosive.Weight-loss type feeder 110 can be formed by corrosion resistant material structure, such as austenitic stainless steel of described corrosion resistant material, or for example 304,304L, 316 and 316L or other suitable corrosion resistant materials, so that an economically feasible balance to be provided between equipment life and fund cost.In addition, resistant material can prevent the corrosion contamination of product.Other resistant material is preferably attacked than the more resistance to AA of carbon steel.The HMD of high concentration, as be greater than 65% HMD, carbon steel is not had to corrosivity, therefore carbon steel can be used for storing concentrated HMD, and stainless steel can be used for storing the more HMD of dilute concentration.

Although shown an exemplary weight-loss type feeder 110, other acceptable weight-loss type feeders can comprise: Acrison402/404,403,405,406 and 407 types; Merrick570 type; K-Tron KT20, T35, T60, T80, S60, S100 and S500 type; And Brabender Flex Wall ^tMplus and Flex Wall ^tMclassic.Acceptable weight-loss type feeder 110 should be able to be realized enough continuous commercial off-the-shelf feed rates.For example, feed rate can be at least 500Kg/hr, for example at least 1000Kg/hr, at least 5000Kg/hr or 10000Kg/hr at least.In embodiment of the present utility model, also can use higher feed rate.

direct insertion disperser

In the time dissolving AA powder, the utility model has been created a kind of homogeneous mixture as the PBA solution that contains HMD and water.Water contributes to dissolve AA, because HMD is not enough to dissolve AA powder.Water also can be conducive to reduce the freezing point of the mixture obtaining.The solubility of adipic acid in water is lower, thus do not have HMD under, require high storage concentration.

Turn back to direct insertion disperser 170, in one embodiment, direct insertion disperser 170 is preferably one way disperser, and it can be used as intermittently or continuous mixing device moves.Required nylon salt solution all AA substantially is passed through to direct insertion disperser 170, therefore in continuous stirred tank reactor 140, do not have AA powder to need to dissolve.The dispersion that is rich in AA 171 that direct insertion disperser 170 is produced, described in be rich in AA dispersion 171 can be used as PBA solution 172 and be pumped to continuous stirred tank reactor 140.Advantageously, this has improved the homogeneity of the AA powder that is fed to reactor 140, and has significantly increased the storage capacity of adipic acid in technique.For example, with liquid PBA solution 172, AA powder 102 can be stored in be arranged in ground elevation 13015m with casing (not shown), for example, be more preferably arranged in ground elevation 13010m with casing.Therefore, the loading of casing is more easily realized.

Direct insertion disperser 170 can have one or more gas port (not shown)s, for injecting nitrogen to remove oxygen.If use blanket of nitrogen, passes into suitably technique unit described in the humidity ratio that the nitrogen of gas port contains and is subject to the humidity of surrounding air little.For example, can use drying nitrogen.

Due to the low-solubility of AA powder in water, need heat that the AA powder being dissolved in water is maintained to figure.Maintaining liquid necessary heat can change with water concentration is different.The utility model uses HMD and water with further hydrotropy AA powder, and forms the PBA solution 172 that contains mixture, and described mixture can store at low temperatures.Advantageously, the low temperature of mixture reduced be generally used for prevent slurry form additional energy.In one embodiment, PBA solution 172 can be remained on to the temperature between 50 DEG C and 60 DEG C with homogeneous phase solution, as the temperature between 55 DEG C and 60 DEG C.Within the limited time, this mixture can be slurry, until acid has time enough to be dissolved completely, at this moment this mixture becomes the solution of clarification, homogeneous phase.Condition and the temperature of setting composition, make initial slurry can not remain on slurry state, but be transformed into the solution of clarification, homogeneous phase.The solution time of AA is depended on variable, and this variable is as energy, temperature etc.

In one embodiment, water 103 and HMD104 can be entered to direct insertion feeder 170 through liquid-inlet 178I, the AA powder being weighed by weight-loss type feeder 110 102 is passed into direct insertion feeder 170 through solids inlet 178s.For the purpose of this utility model, can be used to form the required needed water of nylon salt solution with the salinity between 50% and 65% by least 80% and directly introduce in direct insertion disperser 170, more preferably at least 90% required water.Usually, can in reactor recovery tower 131 or continuous stirred tank reactor 140, add the charging 103 ' by way of compensation of extra water, for example, add the Part II of water, to realize required salinity.Pass into HMD104 in direct insertion disperser 170 can be form the required HMD104 of nylon salt solution 10% and 60% between, for example required HMD 25% and 45% between.The HMD104 passing in direct insertion disperser 170 can be the anhydrous water that maybe can contain between 0 % by weight and 20 % by weight.The temperature that passes into the HMD104 of direct insertion disperser 170 can be enough to stop solidifying of HMD, usually above 40 DEG C, for example, higher than 45 DEG C.Can at room temperature add water to form the HMD solution 176 having higher than the dilution of the temperature of 40 DEG C, for example, higher than the temperature of 45 DEG C.In one embodiment, the HMD solution 176 of dilution comprises the water between HMD and 70 % by weight to 85 % by weight between 15 % by weight and 30 % by weight, more preferably comprise HMD between 20 % by weight and 30 % by weight and the water of 70 % by weight to 80 % by weight, and the HMD solution 176 of described dilution can pass into direct insertion disperser 170.

In one embodiment, at fresh HMD be also fed under the existence of water of direct insertion disperser 170, by AA powder dissolution in direct insertion disperser 170.Therefore the salting liquid that, comes autoreactor 140 or storage tank 184 or storage tank 195 does not pass in direct insertion disperser 170 to dissolve AA powder.The recirculation of salting liquid reduces the technique capacity up to 50%.

In the time using batch technique, can one or many be filled with continuously AA, HMD and water are passed in direct insertion disperser 170.In one embodiment, monomer can be filled with for twice to direct insertion disperser 170.Be filled with can be between 0.1 and 20 second, for example, preferably between 1 and 15 second at every turn.Be filled with for the first time AA, HMD and the water that can comprise part.In one embodiment, in the time being filled with for the first time, introduce the AA powder between 15% and 35%, the preferably AA powder between 20% and 30%.The temperature of the solution in direct insertion disperser 170 is filled with and fast rise along with first.Second is filled with and comprises the part that maintains AA.Also can increase additional AA is filled with.Owing to having increased being filled with subsequently, and in direct insertion disperser 170, occur further to mix, temperature can be because the heat absorption of AA be dissolved and reduces in water.More than described method can maintain the initial temperature of liquid HMD by the temperature of the solution in direct insertion disperser 170, for example, more than 45 DEG C, to avoid forming solidifying of slurry or solution.Therefore, dispersion 171 is not slurry.

Direct insertion disperser 170 forms the dispersion 171 of homogeneous.The composition of dispersion can be change and generally comprise the water between HMD and 39 % by weight and 57 % by weight between AA, 11 % by weight and 15 % by weight between 32 % by weight and 46 % by weight, more preferably, comprise the water between HMD and 41 % by weight and 47 % by weight between AA, 13 % by weight and 15 % by weight between 40 % by weight and 46 % by weight.In one embodiment, the weight of the AA in PBA solution is at least the twice of the weight of the HMD in PBA solution.In one embodiment, dispersion 171 comprises the balanced salt (for example adipic acid hexamethylenediamine salt) between 25% and 50%, and free adipic acid between 15% and 40%.The solid concentration of dispersion 171 can be less than 60%.Solid concentration comprises balanced salt and free adipic acid.Usually, dispersion does not contain any free HMD and is passed into all chemical bondings in balanced salt of all HMD in direct insertion disperser 170.PBA solution 172 has the composition identical with dispersion 171 and solid concentration.

In an exemplary embodiment, as shown in Figure 3, direct insertion disperser 170 comprises inner chamber 177, and described monomer passes into described inner chamber by one or more imports 178; Multiple agitators 179, for providing mechanical shear stress and reducing the particle size of AA powder 102.As shown in the figure, direct insertion disperser 170 can have powder inlet 178s and liquid-inlet 178I, both passes into inner chamber 177.Described multiple agitator 179 rotates around inner chamber 177.In one embodiment, can deposit at least two different, to there is space isolation leaf slurry 180 agitators.Monomer enters exocoel 181 through multiple agitators 179 and is discharged from through outlet 183.As shown in Figure 2, outlet 183 enters storage tank 184 through recirculation circuit 185.As shown in the figure, pipeloop is back to the bottom of storage tank by one or more internal spray blenders 186, and described internal spray mixture 186 is for example displacer.In one embodiment, internal spray blender 186 can be placed between 0.3 and 1.5 meters of storage tank 184 bottoms and locate, and preferably between 0.5 and 1 meter, locates.Can use one or more jet mixers 186 dispersion 171 is mixed or be mixed in storage tank 184.PBA solution 172 can be taken out from recirculation circuit 185 as required, and pass into continuous stirred tank reactor 140.For the purpose of this utility model, the pressure while entering direct insertion disperser 170 through the liquid charging of liquid-inlet 178I can be higher than atmospheric pressure, and produces low-pressure area (sub-atmospheric pressure), and the suction of solid through solids inlet 178s occurs.Although Fig. 2 and 3 has shown an exemplary direct insertion disperser 170, other acceptable direct insertion dispersers can comprise QUADRO YTRON ^tM, blender, blender, and high shear stress blender.

In some embodiments, direct insertion disperser 170 can have the pressure reduction that is less than 200kPa, as is less than 170kPa or is less than 100kPa.The use that disperser is discharged to the kinetic current of the jet mixer 186 of dispersion 171 in storage tank 184 may require 175 and 350kPa between higher pressure.In order to increase disperser through exporting 183 pressure of discharging, can there is an outside displacer 187 in the joint portion place that discharges dispersion 171 and recirculation circuit 185 at disperser.Recirculation circuit 185 is as the kinetic current for outside displacer, for dispersion 171 provides supercharging.In another embodiment, can use booster pump (not shown) to replace outside displacer 187 that dispersion is drained into storage tank 184.

In one embodiment, recirculation circuit 185 directly measures or tests salinity or the pH value of PBA solution 172 without any analyzer.In some embodiments, can come density measurement and temperature and infer pH value by service property (quality) flowmeter.Therefore, do not come to regulate PBA solution 172 by adding monomer in response to the pH measurement of the liquid in storage tank 184.

In one embodiment, recirculation circuit 185 is not connected to measure or sample the dispersion of storage, i.e. PBA solution 172 with any analyzer.Therefore, do not regulate PBA solution 172 in response to the pH measurement of the liquid in storage tank 184.Under the prerequisite of the charging of low variational stable AA powder, can make PBA solution fully be controlled, and not need monitoring or control the contents in storage tank 184.

Storage tank 184 can have the capacity of the solution of the outfit as many as stock's of 5 days PBA, more preferably the stock of 3 days at the most.Although only shown a storage tank 184, can be understood as and can use multiple storage tanks to ensure enough stocks.This makes direct insertion disperser 170 can move independently to dissolve adipic acid and the crude salt obtaining was stored before forming nylon salt solution.Can, in atmospheric pressure or a little higher than atmospheric situation, storage tank 184 be maintained under inert atmosphere, under nitrogen atmosphere.Storage tank 184 can have outlet 174 for removing waste gas.

Storage tank 184 can be maintained to the temperature between 50 DEG C and 60 DEG C, preferably the temperature between 55 DEG C and 60 DEG C.Advantageously, can improve operating efficiency for the lower temperature of storing, reduce the degraded of salt and fall low-energy-consumption.For example, do not store and directly charging PBA solution to continuous stirred tank reactor 140, can provide the stock of 2-8 hour, and the charging from storage tank 184 of PBA solution can be obtained to the stock of 3-5 days, this is an advantage of the present utility model.This has reduced, and due to the loss of PBA solution feed, the potential of the interference to continuous stirred tank reactor 140 may.In storage tank 184, can there is interior heater 188.In addition, recirculation circuit 185 can have one or more heaters 189, is used to storage tank 184 that heat is provided.Adjustable throttle, to interior heater 188 or the steam of one or more heater 189 or the flow velocity of hot water, maintains the temperature required of storage tank 184.

In one embodiment, not by monomer being added to the pH value of directly measuring or regulate PBA solution 172 in storage tank 184 in PBA solution 172 and/or storage tank 184.Owing to being rich in AA, PBA solution 172 and following nylon salt solution phase ratio, acidity is stronger, and more insensitive to component difference.In one embodiment, in PBA solution 172 is introduced to continuous stirred tank reactor 140 before, do not need to measure the pH value of PBA solution 172.In some optional embodiments, can use the pH value measuring instrument appending.

As described in the utility model, form PBA solution and not only reduced the quantity of a series of salt reactor with direct insertion disperser 170, and PBA solution has also advantageously improved the stock of the adipic acid in technique, and under the significant cryogenic conditions decomposing for reducing salt, bear the target salt stock of a part as semi-finished product stock, improve the homogeneity of the AA charging being fed in continuous stirred tank reactor 140, and it is the same to stop property-modifying additive with polymerization, has eliminated the PBA equipment at intermittence separating.

reactor

In an embodiment of the present utility model, in single continuous stirred tank reactor 140 as shown in Figure 4, be prepared into nylon salt solution from PBA solution 172.Continuous stirred tank reactor 140 can produce enough turbulent flows, for the production of the nylon salt solution of homogeneous phase.For the purpose of this utility model, " continuous stirred tank reactor " refers to a reactor and do not comprise multiple reactors.In addition, single reactor does not comprise direct insertion disperser 170.The utility model can be realized the nylon salt solution of homogeneous phase and not require the multiple tandem reactors as used in conventional method in single container.Applicable continuous stirred tank reactor is single container reactor, as non-tandem reactor.Advantageously, this has reduced in the capital input with in commercial mass production nylon salt solution.When combine use with weight-loss type feeder described herein, continuous stirred tank reactor can be realized the nylon salt solution of homogeneous phase, and it has realized target pH value and target salinity.

Nylon salt solution is withdrawn from from reactor 140, and be directly delivered to storage tank 195.Between in withdraw from and enter storage tank 195 from continuous stirred tank reactor 140, no longer monomer (AA or HMD) is introduced in nylon salt solution.More specifically, nylon salt solution is withdrawn from and is entered conduit 144 from recirculation circuit 141, and in conduit 144, does not add monomer.On the one hand, conduit 144 does not have the import for introducing additional monomers, and described additional monomers can comprise dicarboxylic acids and/or diamines.Therefore,, by additional monomers being introduced to the pH value that further regulates nylon salt solution in conduit, particularly do not regulate by adding extra HMD.As required, can mix and filter extra nylon salt solution, as described in the utility model, monomer can only be passed in single continuous stirred tank reactor.Therefore, described disclosed method can not need the series connection of multiple containers and think that before this necessary pH value is measured and the consecutive steps of adjusting, and keeps stable metering balance between AA and HMD, to manufacture nylon 6,6.

Continuous stirred tank reactor 140 can have the draw ratio between 1 and 6, as the draw ratio between 2 and 5.Can build reactor 140 so that an economically feasible balance to be provided between equipment life and fund cost with following material, described material select free Hastelloy C alloys (Hastelloy C), aluminium, austenitic stainless steel (austenitic stainless steel, as 304,304L, 316 and 316L) or the group that forms of other applicable anticorrosives.Can carry out selection material by the temperature in consideration continuous stirred tank reactor 140.The time of staying in continuous stirred tank reactor 140 can be according to its size and feed rate and difference is less than 45 minutes conventionally, as is less than 25 seconds.Liquid is withdrawn from and is entered in recirculation circuit 141 from lower part outlet 148, and nylon salt solution is withdrawn from from conduit 144.

General, applicable continuous stirred tank reactor comprises that at least one monomer import introduces HMD and/or water and one for introducing the import of PBA solution.Described import directly passes into the top of reactor.In some embodiments, can carry out charging monomer at liquid level place with suction pipe.Can there are multiple imports, for each component is introduced to reaction medium.Fig. 4 has shown an exemplary reactor 140.In the time using PBA solution, preferably the aequum of the AA for nylon salt solution is passed into direct insertion disperser 170 to produce PBA solution 172.Therefore, continuous stirred tank reactor 140 preferably has PBA import 145 and HMD import 146 and solid is not introduced in continuous stirred tank reactor 140.Can introduce HMD with pure HMD104 ' or with the form of the aqueous solution, the described aqueous solution contains the HMD (for example containing the HMD between 65 % by weight and 100 % by weight) between 20 % by weight and 100 % by weight, and contains the water (for example containing the water between 0 % by weight and 20 % by weight) between 0 % by weight and 80 % by weight.The HMD104 ' that passes into continuous stirred tank reactor 140 for form the required HMD of nylon salt solution 20% and 70% between, be for example required HMD 30% and 55% between.Can introduce HMD104 ' by import 146, described import 146 is adjacent with the import 145 of PBA solution 172.Because the tolerance of salinity does not have the strict of pH value, can introduce water in multiple positions, for example as described in the utility model, can be by import 145 and/or 146 and/or introduce water by pump 149.Optionally, can there is the import 147 for being introduced separately into water.Can also introduce water by reactor recovery tower 131.In some respects, recovery tower 131 can be vent condenser.Because most water is introduced with PBA solution 172, therefore only need a small amount of water to realize required salinity.

Liquid in reactor 140 is withdrawn from continuously, and by recirculation circuit 141.Recirculation circuit 141 can comprise one or more pumps 149.Recirculation circuit 141 also can comprise Temperature-controlled appliance, temperature measurement equipment and controller, described in, Temperature-controlled appliance is for example coil pipe, chuck or the device that comprises heat exchanger.The temperature of the nylon salt solution in Temperature-controlled appliance control recirculation circuit 141, to prevent the boiling of nylon salt solution or to form slurry.When introducing extra HMD by pipeline 107, during as compensation HMD, preferably introduce HMD at 142 places, crosspoint, upstream of one or more pumps 149 and the upstream of any pH or salinity analyzer.As described in further discussing in the utility model, compensation HMD107 can contain form the required HMD of nylon salt solution 1% and 20% between, for example, required HMD 1% and 10% between.Crosspoint 142 can be the import interface that enters recirculation circuit 141.Except the described liquid that circulates, pump 149 also works as the second blender.Pump can have following functions simultaneously, is about to compensation HMD and introduces in recirculation circuit 141, and compensation HMD is mixed with the liquid of withdrawing from from reactor.The group of the formation of the optional free vane pump of described pump, piston pump, flexible member pump, lobe pump, gear pump, circumference piston pump and screw pump.In some embodiments, pump 149 can be placed in 142 places, crosspoint.In other embodiments, as shown in the figure, pump 149 can be in the downstream in crosspoint 142, still before crosspoint 143.After preferably the second mixing occurs in and adds all HMD, comprise by pipeline 107 and add compensation HMD, and in any analysis or before in withdrawing storage tank 195 to.In an optional embodiment, one or more static mixers can be set in the recirculation circuit in the downstream of pump 149 141.At Perry, Robert H., and Don W.Green.Perry ' s Chemical Engineers ' Handbook.7th ed.New York:McGraw-Hill, in 1997:18-25to18-34, further describe exemplary static mixer, be combined in by reference in the utility model.

At 143 places, crosspoint, nylon salt solution can be withdrawn in conduit 144.The time of staying in conduit 144 can be according to the position of storage tank 195 and filter 190 and difference is less than 600 seconds conventionally, for example, be less than 400 seconds.In one embodiment, operable valve 150 is controlled the pressure of nylon salt solution.Although only shown a valve, be understandable that, in recirculation circuit 141, can use extra valve.Do not have monomer (as AA or HMD) be introduced into the downstream in crosspoint 143 or enter in conduit 144.In addition,, under normal operating condition, do not have monomer to be introduced in storage tank 195.

Recirculation circuit 141 also can comprise heat exchanger 151, for controlling the temperature of reactor 140 liquid.Can control described temperature by the temperature controller (not shown) of using in reactor 140 or continuous stirred tank reactor 140 exports (not shown) place.Can use inner heat exchanger, as coil pipe or jacketed reactor (not shown), regulate the temperature of described liquid.Can be heat exchanger 151 cooling water is provided, more than described cooling water maintains the freezing point of salt of given concentration.In one embodiment, heat exchanger can be indirect shell heat exchanger or tubing heat exchanger, spiral or plate and frame heat exchanger, or for reclaiming hot reboiler from reactor 140.The temperature of reactor 140 maintains the scope between 60 DEG C and 110 DEG C, to prevent that slurry from forming and Crystallization.Along with the concentration of water rises, the temperature that maintains solution declines.In addition the low temperature, the temperature of reactor 140 being kept stops the oxidation of HMD.Also can provide blanket of nitrogen protection to stop the oxidation of HMD.

As shown in Figure 4, in one embodiment, reactor 140 has inner coil pipe 152, refrigerant can be passed in described inner coil pipe 152, so that the temperature of reactor is adjusted between 60 DEG C and 110 DEG C.In another embodiment, reactor 140 can be with the chuck (not shown) containing refrigerant.Inner coil pipe can react the heat producing by recovery and regulate temperature.

Except temperature controller, reactor 140 also can have the atmosphere air vent with vent condenser, to maintain the atmospheric pressure in reactor 140.Pressure controller can have inside and/or external pressure sensor.

In one embodiment, also can there is sampling line 153, for measuring the pH value of nylon salt and/or the concentration of salt.Sampling line 153 can be communicated with recirculation circuit 141 fluids, and preferably receives the fixed flow of flowing through, to reduce to greatest extent the impact of flowing on analyzer.On the one hand, sampling line 153 can be withdrawn from the nylon salt solution that is less than 1% in recirculation circuit 141, is more preferably less than 0.5%.In sampling line 153, can there are one or more analyzers 154.In some embodiments, sampling line 153 can comprise filter (not shown).In another embodiment, sampling line 153 can comprise suitable heating or cooling device, as heat exchanger, carrys out the temperature of Quality control stream.Similarly, sampling line 153 can comprise water-filling pipeline (not shown), regulates concentration for water being joined to sample stream.If water is added in sample stream, water can be deionized water.Calculate by the water of sampling line 153 chargings, to maintain target salinity, and other chargings of going back adjustable water.Analyzer 154 can comprise in-line analyzer, for real-time measurement.According to the type of sampling, tested part can or be discharged via pipeline 155 Returning reactors 140.Sampling line 153 can return by recirculation circuit 141.In addition, sampling line 153 is back to reactor 140 in different positions.

Continuous stirred tank reactor 140 keeps liquid level 156, and described liquid level 156 is at least 50% completely, and for example, at least 60% is full.Select liquid level to make it be enough to be submerged in the blade in CSTR, thereby prevent the foaming of nylon salt solution.Can introduce nitrogen or other inert gas to above-mentioned liquid level 156 upper spaces by gas ports 157.

The inside of continuous stirred tank reactor 140 can provide enough mixing to produce the required nylon salt solution with homogeneous pH value.As shown in Figure 4, have shaft 158, it extends vertically into and passes through continuous stirred tank reactor 140 center.Preferably, shaft 158 extends along the center line of reactor 140, but in some embodiments, shaft 158 can pass through center.In optional embodiment, shaft tilts.As long as can realize required mixing, also can use the shaft of off-axis.

Shaft 158 can have one or more impellers 159, as paddle, hurricane band, anchor, Corkscrews, screw and/or turbine.Preferably aial flow impeller, for mixing AA and HMD, because these impellers are tending towards preventing the bottom of solid particles sediment at reactor 140.In other embodiments, impeller can be the radial turbine of flat sword, and described radial turbine has the multiple blades with plectane surrounding equi-spaced apart.In whole shaft 158, can there is the impeller between 2 and 10, for example, between 2 and 4.Blade 160 on impeller 159 can be straight, bending, recessed, protruding, angled or inclination.The quantity of blade 160 can change between 2 and 20, for example, between 2 and 10, changes.If needed, blade 160 can also have stabilizer (not shown) or scraper (not shown)

In an exemplary embodiment, shaft can be three pitches (triple-pitch) turbine assemblies.In such assembly, shaft 159 comprises at least one upper angled blade turbomachine (not shown) and at least one lower tilt blade turbine (not shown).In the turbine assembly of three pitches, preferably offset with the inclined plane of lower tilt blade turbomachine on the inclined plane of upper angled blade turbomachine.

Also can use the many stirrer shafts with dissimilar impeller, as spiral and anchor.In addition, also can use side dress shaft, particularly those have the side dress shaft of marine propeller.

Drive shaft 158 by external motors 165, can 50 and 500rpm between rotating speed mixing material, for example, 50 and 300rpm between rotating speed.Shaft 158 can be installed to the motor drive shaft 166 on connector 167 removably.The speed of motion can be different, but generally, described speed should be enough to keep the whole surf zone of solid particle to contact with liquid phase, guarantees to maximize available interface zone, for solid-liquid mass transfer.

Reactor 140 can also comprise one or more deflection plates 168, for mixing and prevent the formation in dead band.The quantity of deflection plate 168 can change between 2 and 20, for example, between 2 and 10, and at the periphery of reactor 140 by interval equably.Deflection plate 168 can be arranged on the inwall of reactor 140.In general, use vertical baffling plate 168, but also can use bending deflection plate.Deflection plate 168 is extensible higher than the liquid level 156 in reactor 140.

In one embodiment, reactor 140 comprises steam vent, for removing waste gas through pipeline 135; A recovery tower 131, for being back to reactor 140 by condensable HMD.Water 132 can be transported to recovery tower 131 and 133 reclaim at the bottom of the tower of recovery tower 131.Pass into water to keep the efficiency of recovery tower 131 with minimum-rate.Calculate by the water of recovery tower 131 chargings, to keep target salinity, and regulate the charging of other water.Emptying gas 134 can be condensed and can return through pipeline 133 with recycle-water and monomer waste gas.Not condensable gases, comprises nitrogen and air, can be used as waste gas streams 135 and is removed.In the time that recovery tower 131 is a vent condenser, recovery tower 131 can be used to reclaim waste gas and remove uncondensable gas.

Although shown an exemplary CSTR, also can use other acceptable continuous stirred tank reactor.

the storage of nylon salt solution

As shown in Figure 3, along with nylon salt solution forms, it is transported to storage tank 195, and wherein nylon salt solution can be kept until polymerisation needs.In some embodiments, storage tank 195 can comprise recirculation circuit 193, with the nylon salt solution that circulates.Can use internal spray blender 194 to keep the circulation in storage tank 195.In one embodiment, internal spray blender 194 can be between 0.3 and 1.5 meters of bottoms apart from storage tank 195, preferably between 0.5 and 1 meter.In addition, in some embodiments, at least a portion in nylon salt solution can be returned to reactor 140, to prevent that production line from freezing and/or in the time that system is chaotic or when required target pH value and/or target salinity change, and correction nylon salt solution.Also any untapped nylon salt solution can be turned back to storage tank 195 from this polymerization 200.

Holding vessel 195 can be formed by resistant material structure, as austenitic stainless steel, for example 304,304L, 316 and 316L, or other suitable resistant materials, so that an economically feasible balance to be provided between equipment life and fund cost.Storage tank 195 can comprise one or more storage tanks, and this depends on the volume of the nylon salt solution of storage tank size and needs storage.In some embodiments, nylon salt solution is stored at least two storage tanks, for example, and at least three each and every one storage tanks, at least four storage tanks, or at least 5 storage tanks.Storage tank 195 can remain at the temperature more than freezing point of solution, as the temperature between 60 DEG C and 110 DEG C.For the nylon salt solution with the salinity between 60 % by weight and 65 % by weight, temperature can remain between 100 DEG C and 110 DEG C.In storage tank, can there is interior heater 196.In addition, recirculation circuit can have one or more heaters 197, is used to storage tank that heat is provided.For example, storage tank can have the capacity of the outfit as many as stock's of 5 days nylon salt solution, more preferably reaches the stock of 3 days.Storage tank can be maintained in blanket of nitrogen under atmospheric pressure or a little higher than atmospheric pressure.

In some embodiments, before entering storage tank 195, can filter nylon salt solution to remove impurity.Can filter nylon salt solution by least one filter 190, for example, at least two filters or at least three filters.Filter 190 can be configured to serial or parallel connection.Suitable filter can comprise film filter, and described film filter comprises polypropylene, cellulose, cotton and/or glass fibre.In some embodiments, filter can have aperture size between 1 to 20 micron, for example, and between 2 and 10 microns.Filter can be also ultra filtration filter, micro-filtration unit, nanometer filtration filter, or active carbon filter.

compensation HMD

In as noted before, at least three positions, the HMD of the equivalent required nylon salt forming is introduced with different parts, to form nylon salt solution.Add Part I and form PBA solution.In addition, can fixedly join the feed rate of the part of the HMD of direct insertion disperser, to provide the HMD of necessary amount to dissolve AA powder.By second and Part III join in CSTR to form nylon salt solution.In order to use single continuous stirred tank reactor, and form uniform nylon salt solution, once nylon salt solution is discharged and entered conduit 144 from reactor 140, and enter subsequently storage tank 195, no longer add HMD.As shown in Figure 4, can carry out by being included in 142 places, crosspoint the variance control of further meticulous goal standard (for example target pH value) via the Part III (as compensation HMD) of the HMD of pipeline 107.Compensation HMD is generally a minimum part of the HMD adding, and with the vernier control of making the pH to nylon salt solution, due to than main HMD charging, uses less valve to have the higher control of minor variations of convection cell.Regulating feed rate or the flow velocity of main HMD is not the method for optimizing of the pH value for controlling nylon salt solution, because the time difference between the adjusting of main HMD and the measurement of pH value.In addition, because compensation HMD is the least part that adds the HMD in CSTR, compensation HMD can allow to regulate more accurately the pH value of nylon salt solution, and pH analyzer can provide nearprompt feedback.The upstream of measuring in pH value adds compensation HMD, to reduce the delay of measuring the impact that adds the pH value that compensates HMD.In the time regulating compensation HMD, the also feed rate of adjustable water, to be controlled at the concentration of the solid in this nylon salt solution.Can such adjusting be set and can monitor such adjusting by refractometer on sampling line 153 by controller, as described herein.

Before entering conduit 144, compensation HMD107 can be combined with nylon salt solution phase.If there is no theoretical constraint, think that compensation HMD107 can react with any remaining free adipic acid in nylon salt solution.In addition, as mentioned above, can be with adding compensation HMD107 to regulate the pH value of nylon salt solution.

In one embodiment, the utility model relates to the PBA solution 172 that is metered into continuous stirred tank reactor 140; The aqueous solution and the water 103 ' that will comprise respectively the Part I of HMD104 ' are introduced continuous stirred tank reactor 140, to form nylon salt solution; And the Part II of introducing HMD, for example the compensation HMD to nylon salt solution by pipeline 107.Can be by the Part I of HMD104 ' and water 103 ' in conjunction with to form water-based HMD solution feed.Can compensation HMD107 be joined in the nylon salt solution in recirculation circuit 141 at 142 places, crosspoint.Compensation HMD107 is transported in recirculation circuit 141 continuously with such feed rate, and the flow that described feed rate makes to compensate HMD107 is the medium stream by valve, for example 20% to 60%, 40% to 50%, or approximately 50%.Medium stream refers to and keeps by the continuous-flow of valve, out of hand to prevent.

In order to realize low variational target pH value, the method comprises the constant feed rate that uses weight-loss type feeder 110 that AA powder 102 is provided, to form PBA solution 172; And regulate the feed rate of HMD and water in response to technology controlling and process.Advantageously, can realize high throughput rate by continuous processing.In the time changing salt throughput rate, along with the variation of AA feed rate in discrete segment regulates HMD feed rate pro rata.Can be fed to the feed rate of reactor 140 or HMD and the HMD of charging regulates the feed rate of HMD by way of compensation by changing HMD.One preferred embodiment in, for given salt throughput rate, the feed rate of adjustable compensation HMD107, and the feed rate of the feed rate of HMD104 ' and/or described water-based HMD solution feed can be constant.In another embodiment, the feed rate of compensation HMD107 can be set to constant speed, and if need, can regulate the feed rate of HMD104 ' and/or the feed rate of described water-based HMD solution feed, with realize target pH value and/or salinity.In other embodiments, can regulate HMD104 ' and compensation HMD107 the two feed rate and/or the feed rate of described water-based HMD solution feed, with the concentration of realize target pH value and/or salt.

The HMD source that compensation HMD107 can have and HMD104 ' is identical.HMD104 ' can comprise total HMD in nylon salt solution 80% and 99% between, for example, between 90% and 99%.Compensation HMD107 can be included in total HMD in nylon salt solution 1 and 20% between, for example, between 1% and 10%.Can regulate according to target pH and target salinity the ratio of HMD104 ' and compensation HMD107.The ratio of HMD104 ' and compensation HMD107 can be set by the feed rate model of total HMD as discussed herein.

Compensation HMD can have the source identical with HMD for direct insertion disperser and continuous stirred tank reactor.Can provide HMD by pure HMD, for example, the HMD that comprises at least 99.5 % by weight, for example, 100% HMD and anhydrous; Or the aqueous solution that can contain the HMD between 80 % by weight and 99.5 % by weight provides HMD.Compensation HMD107 is passed into nylon salt solution by form with the aqueous solution of pure HMD or HMD.In the time that compensation HMD is the aqueous solution of HMD, the compensation HMD107 aqueous solution can comprise the HMD between 50 % by weight and 99 % by weight, for example, and the HMD between 60 % by weight and 95 % by weight or the HMD between 70 % by weight and 90 % by weight.As the HMD104 ' aqueous solution, can the required salinity based on HMD source and nylon salt solution regulate the amount of water.Advantageously, the HMD concentration of compensation HMD107 is 90 % by weight to 100 % by weight, to improve the impact of the control on pH value, minimizes the impact of compensation HMD107 simultaneously in salinity control.

Compensation HMD107 is added in the nylon salt solution of recirculation circuit, and described recirculation circuit is in the upstream of pump 149 and sampling line 153.After adding the Part II of HMD107, can use analyzer 154 in sampling line 153, to measure the pH value of the nylon salt solution in recirculation circuit 141.This allows regulating between pH value and pH measurement and having a little delay by the feed rate of compensation HMD107.Do not have extra AA to join recirculation circuit 141.Except compensation, HMD107 is unexpected, does not have HMD to be added to recirculation circuit 141.The Part II of HMD107 is added to the upstream that pH measures, measure with the pH value that allows the Part II that comprises HMD107.

Be different from United States Patent (USP) disclose 2010/0168375 and US Patent No. 4233234 shown in prior art, pH measure after do not add compensate HMD.After pH measures, add HMD, the HMD adding in measurement can produce a large delay during on the affecting of pH value, because before measurement, the HMD of interpolation must pass through reactor.Therefore, add by this way the HMD can undershoot or overshoot target pH value, it causes making these technique less efficientlies operations by continuous pursuing of goal pH value.Advantageously, the upstream that the utility model is measured in pH value increases compensation HMD, so makes the impact that compensates HMD cause little delay and avoid undershoot or the problem of overshoot target pH value.In addition, because maintain valve with medium stream, the utility model charging serially compensation HMD107.

dual AA powder feed

Conventionally,, for the purpose of this utility model, AA powder is passed into direct insertion disperser to produce PBA solution.Therefore, without AA powder is directly introduced to continuous stirred tank reactor.In an interchangeable embodiment, AA powder can be introduced in direct insertion disperser and continuous stirred tank reactor, to form nylon salt solution.Although may there is the independently weight-loss type feeder for the direct insertion disperser of charging and continuous stirred tank reactor, preferably use a weight-loss type feeder.Can prepare in advance and store PBA solution.For example, can comprise for the production of the replaceable continuous process of nylon salt solution: in mass, by measuring the dicarboxylic acids powder from weight-loss type feeder to the first feed pipe, dicarboxylic acids powder is sent to continuous stirred tank reactor by described the first feed pipe; Diamines charging and liquid solution are introduced to continuous stirred tank reactor to form nylon salt solution, and described liquid solution comprises the water between diamines and 39 % by weight and the 57 quality % between dicarboxylic acids, 11 % by weight and the 15 quality % between 32 % by weight and 46 quality %; And in the case of not for dicarboxylic acids or diamines are added to the inserting step of nylon salt solution, from continuous stirred tank reactor, withdraw from continuously nylon salt solution, and pass into storage tank, wherein nylon salt solution comprises the salinity between 50 % by weight and 65 % by weight and comprises the dicarboxylic acids/diamine salts with target pH value, and wherein target pH value is the value that is selected from the scope between 7.2 and 7.9.

process control

As described in the utility model, for example, in the continuous process of the salting liquid for the production of polyamide (nylon salt solution), in the method for prior art, the goal standard (comprising pH and salinity) in nylon salt solution may changing property.May be caused at least in part by AA powder feed rate unpredictable and fluctuation the variability of this goal standard.This unpredictability and fluctuation make control procedure difficulty, because must constantly monitor and be adjusted in this process of downstream of initial reactor before storage.Therefore, the single reactor of the continued operation unpredictable AA powder feed rate with fluctuating of final result effectively.In the past, in order to solve this unpredictability and fluctuation, used multiple reactors, blender and many monomer feed position, especially for the reaction-ure feeding position of adding HMD, to produce the nylon salt solution of goal standard.Use single continuous stirred tank reactor of the present utility model, removed the ability that regulates nylon salt solution in multiple reactors.But, can realize improved technology controlling and process by the variability of leveling AA powder feed rate, by with weight-loss type feeder taking form PBA solution and with this PBA solution as the source of AA forms nylon salt solution, make the variation of AA powder feed rate be less than ± 5%.On the one hand, the utility model adopts the FEEDFORWARD CONTROL (feed forward control) based on model, under the condition that is with or without feedback, realizes the nylon salt solution that has target pH value and salinity.

fEEDFORWARD CONTROL

Before the continuation method starting for the manufacture of nylon salt solution, the throughput rate based on required nylon salt solution carrys out preparation feedback model.Based on this throughput rate, set AA powder feed rate, then target setting pH value and target salinity.Then calculate the feed rate of HMD and the feed rate of water through stoichiometry, with realize target pH value and target salinity.The feed rate of HMD comprises the HMD that forms PBA solution, to the main HMD in reactor, and compensation HMD.The feed rate of water comprises all water sources that pass into direct insertion disperser and reactor 140.Be understandable that, target pH has reflected that AA is than the target mol ratio of HMD.In further embodiment, can in model, add supplementary features, include but are not limited to reaction temperature and reaction pressure.This model is the FEEDFORWARD CONTROL for feed rate is set, for HMD and/or water are fed to direct insertion disperser and CSTR.In certain embodiments, this model also can be for arranging the solution feed of PBA to the FEEDFORWARD CONTROL of continuous agitator tank reactor.

In some respects, this model is the model of preparing by the feed rate of input AA powder, and the feed rate of described AA powder is provided by weight-loss type feeder described in the utility model.This model also can arrange the feed rate of the HMD that is fed to direct insertion disperser, to realize required eutectic mixture.For given throughput rate, the feed rate of AA should be constant.As described in the utility model, weight-loss type feeder can comprise discrete control, to produce low variational AA powder feed rate.Can be continuous, semicontinuous, or with the discrete time interval (as every 5 minutes, every 30 minutes or per hour) feed rate of the AA powder from weight-loss type feeder is offered to model.In other respects, owing to being the low variability of AA powder feed rate, once set the feed rate of AA powder, this model can be set the feed rate of HMD and the feed rate of water.Set these feed rates with realize target pH value and target salinity by model.

This model can be dynamic, and can regulate by the feedback signal of the analyzer from online or off-line.For example,, if expect to change throughput rate, pH or salinity, adjustable model.This model regulates and can be stored in the internal memory of controller, for example programmable logic controller of described controller (PLC) controller, dcs (DCS) controller or proportional-integral-differential (PID) controller.In one embodiment, there is the PID controller of feedback signal can be used to solve the error of model calculating and flow measurement.

Owing to using the feed rate that volume feeder can not Accurate Prediction AA powder, cannot implement to form the low variational nylon salt solution of relative goal standard by FEEDFORWARD CONTROL itself before therefore.This is at least the variability of part because of the AA powder feed rate for being caused by the use of volume feeder.Because the variability of AA powder feed, can not generation model control the ratio of AA and HMD.Result is compared with FEEDFORWARD CONTROL, and these conventional methods can be used FEEDBACK CONTROL, thereby requirement frequently regulates or is a batch method.But when measure AA powder to direct insertion disperser based on weight, FEEDFORWARD CONTROL is enough to produce continuously the low variational nylon salt solution of relative goal standard.

Therefore, in one embodiment, the purpose of this utility model relates to a kind of method of producing for controlling nylon salt solution, it comprises: generate a model for the target feed speed of AA powder, to produce PBA solution, and the nylon salt obtaining has target salinity and/or target pH value.As noted before, target salinity can be the value that is selected from the scope between 50 % by weight and 65 % by weight, for example, and the value of the scope between 60 % by weight and 65 % by weight.Target pH can be the value that is selected from the scope between 7.200 and 7.900, for example, and the value of the scope between 7.400 and 7.700.Described method may further include: with the first feed rate, HMD is introduced to disperser respectively, with the second feed rate, water is introduced to direct insertion disperser, the wherein said first and/or second feed rate is the model based on for PBA solution.Described method also can further comprise: individually PBA solution is introduced to continuous stirred tank reactor with the 3rd feed rate, wherein said the 3rd feed rate is the model based on for nylon salt solution.Described method also can further comprise: individually HMD and water are introduced to continuous stirred tank reactor with the 4th feed rate and the 5th feed rate respectively, wherein, the described the 4th and/or the 5th feed rate is the model of the target feed speed based on for AA powder.HMD and PBA solution reaction form nylon salt solution, and described nylon salt solution can withdraw from continuously and directly enter storage tank subsequently from continuous stirred tank reactor.Can store subsequently this nylon salt solution, for polymerisation in the future.No matter target salinity or the pH value selected, the variability of the relative goal standard of actual specification of nylon salt solution is low, as is less than 0.53% variability, for example, is less than 0.4%, is less than 0.3% or be less than 0.1% variability.

In order further to illustrate according to process control scheme of the present utility model, Fig. 5 has shown a flow chart.In order to simplify, in Fig. 5, get rid of various pumps, recirculation circuit and heater.Fig. 5 has shown several flowmeters, and for example coriolis mass flowmeters (coriolis mass flow meters), volumetric flowmeter, electromagnetic flowmeter and turbine flowmeter, for measuring the logistics of the system of flowing through.In some embodiments, flowmeter also can be measured temperature and/or density.Can be continuous or periodicly by the output valve input control device 113 of flowmeter.There is at least one flowmeter in the upstream of preferred each flowmeter valve.In some embodiments, flowmeter and flowmeter valve can be overall, and in wrapper, come together to provide.Although only shown a controller, can there are in some embodiments multiple controllers.As shown in Figure 5, via pipeline 102, AA powder is delivered to weight-loss type feeder 110, to produce the AA powder feed 139 of metering.Signal 211 is delivered to rotating screw 123 by controller 113.Described signal can be wireless signal.Use a model, the model of this feed rate that is used for feedovering can be stored in controller 113, and described feedforward feed rate is the feedforward feed rate for HMD and water.As mentioned above, weight-loss type feeder 110 regulates the variability of AA powder, so that the AA powder feed 139 with the metering low with respect to target feed rate variation to be provided.For example, weight-loss type feeder 110 can be used the speed that regulates rotating screw 123 from the backfeed loop of weight measurement subsystem 121.

Controller 113 sends to flowmeter valve 214 to regulate water 103 to flow into the flow of direct insertion disperser 170 by feed-forward signal 213.Similarly, controller 113 sends to flowmeter valve 216 by feed-forward signal 215 and regulates HMD104 to flow into the flow of direct insertion disperser 170.By these feed-forward signals of model specification, with realize target pH value and target salinity.HMD and water can be combined into the HMD aqueous solution and be fed to direct insertion disperser 170.

In another embodiment, feed-forward signal 227 is sent to the feed rate that PBA solution 172 that flowmeter valve 228 regulates enters continuous stirred tank reactor 140 by controller 113.In the time not using storage tank 184, must set flowmeter valve 228 throughput rates to direct insertion disperser 170, can limit like this stock.By these feed-forward signals of model specification, with realize target pH value and target salinity.Because feed-forward signal 213 and 215 is used to HMD and water to pass into direct insertion disperser 170, there is no need to take the measurement of the PBA solution 172 of any online or off-line.In order to provide q.s HMD and water to form required nylon salt solution, DCS controller 113 can send respectively feed-forward signal, based on the feed rate of PBA solution 172 that is fed to continuous stirred tank reactor 140, HMD and water are transported to CSTR 140.Feed-forward signal 229 can be based on PBA the target feed speed of solution 172, and feed-forward signal 229 can be controlled flowmeter valve 230 so that the HMD104 ' of aequum is provided to continuous stirred tank reactor 140.In addition, also feed-forward signal 217 being sent to flowmeter valve 218 regulates compensation HMD107 to flow to the flow of recirculation circuit 141.This model can determine that HMD's sends into the relative quantity of HMD107 of the HMD in direct insertion disperser 172, main HMD104 ' and compensation by HMD104.Controller 113 also can send feed-forward signal 231, and feed-forward signal 231 controllable flow rate meter valves 232 are to be supplied to continuous stirred tank reactor 140 by compensation water 103 '.Compensation water 103 ' directly can be supplied to continuous stirred tank reactor 140 or be supplied to continuous stirred tank reactor 140 by exhaust line.Regulate feed-forward signal 217 and feed-forward signal 229, to ensure to exist the output medium stream of the flowmeter valve 217 that flows to compensation HMD107.In one embodiment, model can be set up flow rate to guarantee to compensate the constant flow that HMD107 maintains, i.e. intermediate flow, and described flow rate is sent to flowmeter valve 218 by feed-forward signal 217.

secondary process control

Except using the FEEDFORWARD CONTROL based on modeling, as shown in Figure 5, process control can comprise the feedback signal as the second process control, with realize target pH value and target salinity.These feedback signals can be the measurement data of obtaining from flowmeter and in-line analyzer 154, and flowmeter and in-line analyzer 154, for being adjusted in the charging of HMD and water, preferably regulate the charging of compensation HMD and water.In-line analyzer 154 can comprise pH probe, refractometer and combination thereof.PH probe and refractometer can serial or parallel connections.

As shown in Figure 5, the method is used in-line analyzer 154, and the pH value that for example online pH meter 154 is measured the nylon salt solution in recirculation circuit 141 is to produce feedback signal.For the ease of the on-line measurement of the pH value of nylon solution, nylon salt solution is taken out continuously and at least a portion in nylon salt solution is passed in recirculation circuit 141 and sampling line 153 from reactor.Recirculation circuit 141 can comprise flowmeter (not shown) and flowmeter valve.In another embodiment, recirculation circuit 141 can comprise pressure controller (not shown), to control the flow of nylon salt solution.Preferably, nylon salt solution is constant by the stream of recirculation circuit 141.Sampling line 153 comprises the instrument (for example pH meter) for pH value determination and/or the instrument (for example refractometer) of measuring for salinity.In one embodiment, under the condition of reactor, under without any dilution or cooling condition, measure the pH value of at least one part of nylon salt solution.Then by least a portion of described nylon salt solution directly or be back in reactor 140 through vent condenser 131.When at least a portion of described nylon salt solution is in the time that vent condenser 131 turns back to reactor, nylon salt solution can replace the water passing in vent condenser.Sampling line 153 can also comprise cooler (not shown) and the temperature sensor (not shown) of cooling nylon salt solution, the temperature of described temperature sensor measurement before pH measures.In some embodiments, pH is cooled to target temperature by nylon salt solution before measuring.Described target temperature can be than the target temperature of the scope between low 5 DEG C and 10 DEG C of the nylon salt solution of its outflow reactor 140.Described temperature relatively target temperature being less than ± change in the scope of 1 DEG C, be for example less than ± 0.5 DEG C.Can exist temperature sensor (not shown) to monitor the temperature of the nylon salt solution of the upstream of pH value measurement.

Online pH meter 154 offers controller 113 by output 226 subsequently.The pH value that online pH meter 154 is measured in this output 226 sends to controller 113.Online pH meter 154 is for the variability of the pH value of the nylon salt solution of definite continuous process.In other words, online pH meter 154 can be measured the pH value different from target pH value, but in the time that the pH measuring changes, controller 113 can regulate monomer feed.In a preferred embodiment, the pH value of nylon salt solution being less than ± change in 0.04 scope, be for example less than ± 0.03 or be less than ± 0.015.Due to the drift of the measured value of pH meter online, online pH meter is the variability for pH value determination, instead of measures absolute pH value.This is at least in part due to FEEDFORWARD CONTROL, and described FEEDFORWARD CONTROL allows the target pH value of setting.By determining that with online pH meter whether pH value changes, and can detect variation in process of production.Use secondary control, the variation of pH may cause the corresponding adjusting of at least one feed rate, and it sends to respectively flowmeter valve 218 and 230 by holding wire 217 and 229.On the one hand, when PBA solution 172 passes in reactor 140 with constant, preferably regulate the feed rate of the HMD and the water that are fed to reactor 140, instead of regulate the feed rate that is fed to the direct insertion disperser 172 of producing PBA solution.In order to provide a willing pH to regulate, send signal to valve 218 by circuit 217 and regulate compensation HMD107.The amount of the adjusting compensation HMD107 making is determined by the respective change of the HMD104 ' by flowmeter valve 230.Because meeting affects PBA solution, therefore preferably do not regulate the HMD104 that is fed to direct insertion disperser 172.This adjusting is responsive, once and do not show the variation of pH, it should be able to return to the feed rate of being set by FEEDFORWARD CONTROL.These adjustings to compensation HMD107 also can have influence on the salinity of nylon salt solution.Can be by regulating water to control the variation of this salinity through the signal 231 of flowmeter valve 232.

Because the process of described formation nylon salt solution is continuous, therefore also (for example, continuously) or approach and obtain in real time the pH measurement data of online pH meter 154 in real time.In some embodiments, carried out pH measurement every 60 minutes, for example, every 45 minutes, every 30 minutes, every 15 minutes or every 5 minutes.PH meter can have the precision in ± 0.05, as the precision in ± 0.02.

Except using online pH meter 154, the method can further include the salinity of measuring nylon salt solution with refractometer, and regulates the feed rate of water.In one embodiment, regulate the feed rate of water by being fed to the water charging of recovery tower 131.By adding in the nylon salt solution of described reactor downstream or also adjustable salinity of removal water.

According to the required adjusting based on feedback, also can regulate independently and enter direct insertion disperser 172 and reactor 140 both main HMD and water with secondary control by model.Particularly advantageously when there is the trend of a pH value, it causes the adjusting of long-term compensation HMD107.

Except the feedback from online pH meter 154, each flowmeter 214 ', 215 ', 218 ', 228 ', 230 ' and/or 232 ' also can provide respectively information or mass flowrate to controller 113 via signal 213 ', 215 ', 218 ', 227 ', 229 ' and/or 231 '.Can maintain integral production speed by this information from flowmeter.

The art methods of the pH value of the nylon salt solution that uses pH probe mensuration is disclosed.See that United States Patent (USP) 4233234 and United States Patent (USP) disclose 2010/0168375.But each of these art methods is measured the pH value of nylon salt solution, then add extra diamines and/or acid and regulate pH value.The effect uncertain of extra diamines and/or acid, until extra diamines and/or acid sneaks in reactor, and takes out for measuring again.This method causes " pursuit " pH value, and produces insensitive process control, and it may undershoot or overshoot target pH value.

In the utility model, as shown in Figure 5, preferably compensation HMD107 is supplied to the upstream of online pH meter.Thereby the nylon salt solution of the HMD in compensation HMD107 in reactor recirculation circuit is combined, and measures the pH value of nylon salt solution before recycling by reactor 140.

use the Secondary process control of online measurement in lab

As mentioned above, must not reflect target pH value from the pH measurement data of secondary control procedure, but for calculating the variation of pH value.The sensitivity of measuring in order to improve pH, Secondary process control can also relate to the pH value of measuring the nylon salt solution under controlling in laboratory.There is no theoretical constraint, increased the sensitivity of the pH measurement that approaches flex point place under the condition due to the concentration reducing and temperature, the pH value of measuring nylon salt solution under laboratory condition has improved the precision of measuring.This can allow to detect the little pH that may not be noted under reaction condition and change.For the purpose of this utility model, the condition in laboratory refers to the nylon salt solution example of measuring at the temperature between 15 DEG C and 40 DEG C, for example between 20 DEG C and 35 DEG C or 25 DEG C, ± 0.2 DEG C.The nylon salt solution example of measuring under laboratory condition can have the salinity between lower 8% and 12%, and for example 9.5%.Carrying out online this pH under laboratory condition by the nylon salt solution in dilution and cooling sampling line 153 measures.

As shown in Figure 5, under laboratory condition, for the ease of the pH value of on-line measurement nylon solution, nylon salt solution is taken out continuously from reactor, and by least a portion in nylon salt solution, for example, the nylon salt solution that is less than 1% is drawn as arrived recirculation circuit 141 and sampling line 153.Sampling line 153 is included in the instrument that carries out the measurement of pH value under laboratory condition.Sampling line 153 can also comprise the next cooling nylon salt solution of cooler (not shown).In other embodiments, this cooler can be omitted.The temperature of the nylon salt solution in sampling line 153 and concentration can regulate by adding water via pipeline 220.This water is the sub-fraction of total water feed rate, and described total water feed rate is calculated by model.Add amount and the temperature of water to be enough to reach the needed temperature of nylon salt solution example and the intensity for the dilution of pH measurement.Also can comprise further cooling dilute sample.Under laboratory condition, obtain the pH value of at least a portion of nylon salt solution, then as described herein by least a portion Returning reactor 140 of nylon salt solution.Then online pH meter 154 provides output 226 to controller 113.

As mentioned above, online pH meter 154 is for measuring the variability of pH value of nylon salt solution.In a preferred embodiment, the variation of the pH value of nylon salt solution is less than ± 0.04, for example, be less than ± 0.03 or be less than ± 0.015.Be similar to pH value under reaction condition and measure, due to the drift of online pH meter measured value, use online pH meter under laboratory condition to come the variation of pH value determination instead of measurement target pH value.This is at least in part due to FEEDFORWARD CONTROL, and its permission arranges target pH value.By determining that with online pH meter whether this pH value changes, and can detect variation in process of production.Be similar to Secondary process control, can be by transmitting a signal to circuit 217 and 229, then regulate feed rate to flowmeter valve 218 and 230.These regulate the salinity that also may have influence on nylon salt solution.Regulate water to control the variation of this salinity by sending to the signal 231 of flowmeter valve 232.

Because the process in the nylon salt solution of described formation is continuous, for example, in online pH meter 154 (, continuously) or the nearly pH measurement data obtaining in real time in real time.In some embodiments, every 60 minutes, for example, every 45 minutes, every 30 minutes, every 15 minutes or every 5 minutes, obtain pH measurement data.PH survey tool should have ± 0.05 precision, as ± 0.03 or ± 0.01 precision.

three-stage process control

As shown in Figure 5, although use FEEDFORWARD CONTROL and feedback signal can contribute to reduce the variability of nylon salt solution specification, but still can use further analysis, and particularly use the off-line pH carrying out under laboratory condition to analyze, detect the uniformity of nylon salt solution.This off-line procedure control under laboratory condition is called as three-stage process control, and it can comprise pH and/or salinity measurement.In one embodiment, can be in the pH value of off-line measurement nylon salt solution under laboratory condition, to determine whether to have realized target pH value.Off-line pH value is measured and can also be detected that any instrument problem maybe needs the deviation regulating.In another embodiment, under laboratory condition, the pH value of the nylon salt solution of off-line measurement also can be used to adjust the holding wire 217 and 229 that is connected to flowmeter valve 218 and 230.Under laboratory condition, off-line pH measures the ability can with pH value determination in ± 0.01 scope.

As described in the utility model, laboratory condition refers to the sample of measuring nylon salt solution at the temperature between 15 DEG C and 40 DEG C, as at the temperature between 20 DEG C and 35 DEG C or at 25 DEG C ± 0.2 DEG C, for example, ± 0.2 DEG C.The nylon salt solution example recording under laboratory condition can have the concentration between 8% and 12%, for example, and 9.5% concentration.In order to reach this temperature and concentration, dilutable water the cooling nylon salt solution example taking out from recirculation circuit.Can serviceability temperature bathe the nylon salt solution example of cooling dilution.Can take out sample based on demand, for example every 4 to 6 hours, every day or weekly.In the situation of the system failure, can take out more continually sample, for example, per hour.In the ordinary course of things, off-line analysis instrument can be used to solve the instrumental bias of in-line analyzer.For example, if target pH value is 7.500, in-line analyzer may report that pH value is 7.400, and off-line analysis instrument report pH value is 7.500, and this shows the instrumental bias of online pH analyzer.On the one hand, whenever having carried out off-line measurement, be automatically biased in line analysis instrument by exponentially weighted moving average (EWMA) value.In some respects, the output of off-line analysis instrument is used to proofread and correct any deviation or the drift of in-line analyzer.In other side, do not proofread and correct in-line analyzer, but supervise to survey drift or deviation by off-line analysis instrument.Aspect this, rely on in-line analyzer to determine the variation of pH, for example, outside predefined acceptable changeability.

In another embodiment, off-line analysis instrument can be used for measuring the target salinity of nylon salt solution.The measurement of off-line salinity also can detect problem or adjustable deviation of any instrument.In the time using multiple refractometer, each refractometer may have deviation independently.

nylon polymerization

The described nylon salt solution of the utility model can pass into polymerization process 200 to form polyamide, particularly nylon 6,6.Nylon salt solution directly can be sent into polymerization process 200 from continuous stirred tank reactor 140, or can first nylon salt solution be stored in storage tank 195, then send into polymerization process 200, as shown in Figure 5.

Nylon salt solution of the present utility model has the pH value of homogeneous, and it can improve the performance of polymerizing polyamide process.The pH of the homogeneous of nylon salt solution provides reliable raw material to produce multiple polyamide product.This has greatly improved the reliability of polymeric articles.In the ordinary course of things, polymerization process comprises that evaporation water is to concentrate nylon salt solution from described nylon salt solution; And carry out the concentrated nylon salt of polymerization to form polyamide product by condensation.Can use one or more evaporimeters 202.Can complete evaporation of water in a vacuum or under pressure, to remove at least 75% water in this nylon salt solution, more preferably at least 95% water in nylon salt solution.Dense nylon salt 203 can comprise the water between 0 and 20 % by weight.Can batch or continuous process in carry out condensation.Depend on desired final polymer product, extra AA and/or HMD can join in polymer reactor 204.In some embodiments, additive can be attached in polyamide product.

For the purpose of this utility model, it can be aliphatic that suitable polyamide product has at least 85% carbochain between amide group.

In the time being transported to evaporimeter 202 from storage tank 195, keep the temperature of nylon salt solution more than fusing point, can prevent like this pipeline scaling at it.The steam of catching from evaporimeter 202 in some embodiments, can be used for keeping described temperature.In other embodiments, also can use the cooling water of heating.

Polymerisation can be in single phase reactor or carry out in multistage condensation reactor 204.Can add extra monomer by pipeline 205, AA or HMD, but preferred HMD, to produce different nylon product 208.In one embodiment, a part for PBA solution 172 can be introduced to reactor 204, to produce different nylon product 208.Reactor 204 can comprise the agitator for mixing nylon salt.Reactor 204 also can have chuck to regulate temperature, and described chuck uses heat transfer medium.Condensation reaction in reactor 204 can be carried out in inert atmosphere, and nitrogen can be added in reactor 204.According to initial dicarboxylic acids and diamines, the temperature of polymerisation can change, but conventionally more than the fusion temperature of nylon salt, and more preferably more than fusion temperature at least 10 DEG C.For example, the nylon salt that comprises adipic acid hexamethylene diamine salt has the fusion temperature in the scope between 165 DEG C and 190 DEG C.Therefore, can under the temperature of reactor between 165 DEG C and 350 DEG C, carry out condensation reaction, for example, at the temperature between 190 DEG C and 300 DEG C.Condensation reaction can be carried out under the condition of normal pressure or pressurization.Nylon product 208 removes from reactor with free-pouring solid product form.

The water producing in condensation reaction can remove with the form of vapor stream by reactor ventilation line 209.That described vapor stream can be the condensation of overflowing together along with moisture and gaseous monomer, as diamines, can return it in reactor.

Can carry out subsequent treatment, for example, extrude, spinning, stretching or stretcher strain, to produce polyamide product.Polyamide product can be the group of selecting free nylon 4,6, nylon 6,6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 11 and nylon 12 to form.In addition, polyamide product can be copolymer, as nylon 6/ nylon 6,6.

By nonrestrictive embodiment, method of the present utility model is described below.

Embodiment

embodiment 1

By mechanical (being screw, drag chain) or pneumatic (be pressure air, evacuated air, or closed loop nitrogen (closed loop nitrogen)) induction system, AA powder is delivered to supply container from container bag unloading, the unloading of liner container bag, the unloading of liner box container or hopper compartment debarkation stop.

Supply container is delivered to AA powder weight-loss type (Loss-In-Weight, L-I-W) feeder as requested, and controls by the low level based on selected L-I-W hopper and high-order PLC.Supply container measures AA powder by screw conveyor or rotary table feeder with enough loading speed, to allow to carry out the filling of L-I-W feeder hopper under the maximum time interval, the time interval of described maximum is equivalent to the half from the high position of L-I-W container to the minimum L-I-W efflux time of low level, preferably be less than half, to receive the feedback of the feed rate of L-I-W feeder within least 67% time.

This L-I-W feeder system PLC regulates L-I-W feeder screw speed, to keep charging rate, described screw speed is in the feed rate target receiving from distribution control system (DSC), records from described L-I-W feeder hopper LOAD CELLS.

As shown at Fig. 7, the variability of the feed rate of the adipic acid by weight-loss type feeder, has in continuous feed be less than in 48 hours ± 5% feed-rate variation.As shown in Figure 8, the variation of feed rate can in 48 hours, be less than ± 3%.As shown in Figure 9, the variability of charging rate can in 18 hours, be less than ± 1%.Use the weight-loss type feeder for adipic acid, by having eliminated by the interference to adipic acid feed rate that uses volume feeder to cause, the performance of the feed-rate variation being improved.

embodiment 2

Prepare the model for produce nylon salt solution according to continuous process.Described nylon salt solution comprises water and adipic acid hexamethylenediamine salt.Described model is set to realize the salinity of 63% in nylon salt solution and to realize 7.500 target pH value.Required throughput rate based on nylon salt solution is determined the fine fodder speed of AA.Described salinity based on realizing and pH value, determine the feed rate of HMD and water.With the low rate of change described in embodiment 1, from powder uninstalling system, adipic acid is delivered to weight-loss type feeder.

AA powder feed from L-I-W feeder is supplied to direct insertion disperser, and it mixes the reaction-ure mixture of AA powder and rare HMD solution continuously, has 42.6% AA, the PBA solution of 14% HMD and 43.4% deionized water to produce.The free AA that PBA solution has the solid concentration of 56.7 % by weight and contains 25.1 % by weight and the salinity of 31.6 % by weight.

By based on entering the PBA solution feed speed of continuous stirred tank reactor (CSTR) and determining for the DCS model of the base stock level of PBA solution storage for the DCS set-point of the AA powder feed rate of L-I-W.

HMD solution (98%) is provided to direct insertion disperser from pressure controlled HMD storage recirculation head.Use the measurement data of coriolis mass flowmeters to be also input to DCS, DCS regulates the feed stream flow velocity of the HMD that enters direct insertion disperser, accurately to control the AA that disperses in product stream and the ratio of HMD.The desired value of the salinity for 63% is added 41.2% the HMD amount of being filled with of the HMD amount of being filled with of described technological requirement in direct insertion disperser.

From pressure controlled deionized water supply head, deionized water is supplied to direct insertion disperser.Use the measurement of coriolis mass flowmeters to be also input to DCS, DCS regulates the flow velocity of the feed stream of the deionized water that enters direct insertion disperser, accurately to control the AA that disperses in product stream and the aqueous concentration of HMD.The desired value of the salinity for 63%, PBA solution feed is minimum 56.75% solid (43.25% water), minimized for the vent condenser of reactor with for the injection of the deionized water of concentration compensation adjustment to allow.

Direct insertion disperser product stream and water-based PBA solution in recirculation circuit heat exchanger upstream are stored to circulation to be mixed to improve temperature to the minimum of a value that PBA solution product flows and is at least 50 DEG C, preferably between 55 DEG C and 60 DEG C, to maintain PBA solution product stream as homogeneous phase solution and the crystal that do not suspend.Crossing of these two kinds of logistics combines liquid injection displacer (" displacer " hereinafter), wherein circular flow is as kinetic current, disperser effluent is as discharge currents, to coordinate the required discharge pressure that approaches atmospheric direct insertion disperser, to promote mixing to make homogeneity to maximize with product in storage.Or, can replace displacer to use booster.The recirculation rate of controlling PBA solution storage circular flow provides the enough power flow rate mixing displacer to recirculation conduit and storage tank.Tank mixing displacer is between 0.2 meter and 1.5 meters of pot bottom, for example, and preferably between 0.5 meter and 1 meter, to ensure the mixing completely of direct insertion disperser product and tank content.By the adjusting to recirculation line heat exchanger to logistics flow rate, tank temperature is adjusted between 50 DEG C and 60 DEG C.

The target feed speed of the PBA solution product stream that DCS uses the DCS model of throughput rate based on polymer reactor and target salt inventory level to provide to enter in CSTR, and regulate described target in the time interval that can arrange.Measure PBA solution feed rate and control described PBA solution feed rate by the means of coriolis mass flowmeters, make it reach the target in DSC.

In DCS, control the feed rate of the balance HMD of the feed rate of based target PBA solution with feedforward ratio control loop.The set-point of adjusting DCS balance HMD ratio flow controller keeps compensating HMD valve and is output as medium range, to guarantee that valve is continuously in control range, for 63% salt target, the amount of being filled with of balance HMD be generally be filled with described process HMD amount 48.8% to 56.8%, and when in the time that PBA solution is combined, be about the amount of being filled with of the HMD of 90-98%.

By unnecessary pH meter continuous measurement pH value, described pH meter is in sample recirculation circuit that provided by the recirculation pump of reactor, screening and temperature and flow rates controlled.DCS regulates the feed rate of compensation HMD by the selected pH input value of DCS that the paired online pH comparing continuously measures, to maintain pH value in DCS target set-point.For 63% salt target, the amount of being filled with of compensation HMD is about the 2-10% that is filled with the total HMD in described process.

Regulate the set point of pH value controller according to the algorithm based on statistics, the pH value analysis that described algorithm uses discrete interval takes from the sample in the downstream of reactor; Described algorithm is as the function of pH value, is to realize the peak response of acid/amine balance under the condition of the temperature of 9.5% concentration and 25 DEG C; Or by inputting continuously pH value from in-line analyzer, the concentration of the product to 9.5% of the reactor of its serial dilution/decision and at 25 DEG C of temperature, or serial dilution/decision is from the concentration of the product to 9.5% of reservoir vessel (if preferably) subsequently with at the temperature of 25 DEG C.

To supplement HMD and be injected into recirculation circuit pump intake in main reactor, and to realize the fastest response time to pH meter, and ensure to regulate reactor product to desired value within the shortest time.With pump mixing HMD and reactor salt product, to guarantee that pH meter and densimeter have homogeneous phase solution, measure respectively pH and concentration for it.

Measure continuously the concentration of reactor by unnecessary refractometer, described refractometer is in the sample recirculation circuit same screening being provided by the recirculation pump of reactor and temperature and flow rates controlled.DCS regulates the feed rate of compensation deionized water by the concentration input value that the DCS of the continuous pairs comparison of online measurement of concetration selects, to maintain the target set point of concentration in DCS.For 63% salt target, the amount of being filled with of compensation water is to be filled with 1% to 5% of total Water in described process, preferably approximately 3%.

Reactor product is delivered to continuously storage tank by liquid level control tool by CSTR, and wherein said reactor product further mixes to provide to polymeric device.This transmission comprises the candle filter shell that at least one is arranged in juxtaposition, and described candle filter shell is to fall design for the initial fine pressure that mostly is 34.5kPa (5psig) most under the maximum instantaneous salting liquid transfer rate in the time entering storage.While using synthetic fibers thickness (depth) or fold membrane cartridge, filter core clearance is the absolute value of 10 μ m of minimum, or in the time using Wound-rotor type cotton fiber filter core, filter core clearance is the nominal value of minimum 1 μ m.The selection of filter is carried out in the selection of the value based on the minimum operating temperature that is 110 DEG C.

Saline solution is recycled continuously by salt storage tank, preferably use tank mixing displacer, described tank mixing displacer is at the bottom of tank between 0.5 and 1 meter, so that tank contents overturn to maximize mixing efficiency more fast.

For 63% salinity, by entering the adjusting of steam flow of heat exchanger of recirculation line, regulate the temperature of salt storage tank between 100 DEG C and 105 DEG C.Salt in described storage tank has 7.500 ± 0.0135 pH value of homogeneous.

comparative example A

Prepare mixture from the embodiment 1 of US Patent No. 6995233.The mass concentration of water is equivalent to 10% dense water-based HMD solution and AA powder and sends into continuously in the first stirred reactor, obtain the mixture of the weight ratio with the AA monomer of 81 % by weight and the diamine monomer of 19 % by weight.This mixture can contain a small amount of water, for example, with respect to the water of the weight approximately 7% of AA/HMD mixture.The temperature of mixture is maintained at about to 126 DEG C, to prevent crystallization.

comparative example B

Follow model and the method for embodiment 1, difference is do not have HMD to be transported in direct insertion disperser.The adipic acid that comprises 49.7 % by weight from the PBA solution of storage tank and the water of 50.3 % by weight, and must keep being greater than the temperature of 85 DEG C, solidify preventing.

comparative example C

Follow model and the method for embodiment 1, difference is do not have water to be transported in direct insertion disperser.It is impossible only AA and HMD being fed in direct insertion disperser, because can not dissolve AA at direct insertion disperser in the situation that there is no water, this product will have high viscosity and could process at very high temperature.

comparative example D

Follow model and the method for embodiment 1, difference is, with volume feeder replace L-I-W feeder by AA powder feed to direct insertion disperser.The variation of the relative target pH value of pH value of nylon salt solution is greater than 0.1pH unit.The poor control of pH value can cause significantly higher freezing point, and this is by processing temperature higher needs, to prevent the risk of crystallization.

comparative example E

Follow model and the method for embodiment 1, difference is do not have compensation water to be fed in reactor.The salinity of nylon salt solution is increased to 63.707% from 63%, and this just requires before polymerization, to have higher storage temperature, for example 3.5 DEG C to 4 DEG C.The temperature that is used for the rising of storing will be close to the boiling temperature of nylon salt solution under normal pressure.In order to make up the salinity of increase, the concentration of PBA solution will be needed to reduce, and because there is no compensation water, it will be more difficult realizing uniform concentration.

comparative example F

Follow model and the method for embodiment 1, difference is there is no displacer or booster pump in the junction of dispersion discharge and recirculation circuit.The loss of kinetic current has reduced displacer mixing efficiency, has also lost Vacuum Pressure, and described Vacuum Pressure can make direct insertion disperser discharge in the time there is no back pressure.Another important problem is that being filled with of dispersion do not have enough heads to press the head that mates the recirculation of salt storage tank to press.Due to pressure drop, dispersion effluent does not have enough pressure to enter storage tank.

Although the utility model is described in detail, the amendment in spirit and scope of the present utility model it will be apparent to those of skill in the art.All publications and the bibliography of above-mentioned discussion are incorporated in the utility model by reference.In addition, should be to understand, the part of each side of the present utility model and each embodiment and the various features that are documented in the utility model can be combined or be exchanged in whole or in part.In the description of above-mentioned each embodiment, as will be understood by the skilled person in the art, those enforcement embodiments of having quoted another embodiment can suitably combine with other embodiment.And, it will be appreciated by persons skilled in the art that description is above only mode for example, and be not intended to limit the utility model.

Claims

1. for the production of a process unit for nylon salt solution, it comprises:

A. weight-loss type feeder, comprises hopper, feed pipe, and for connecting the conduit of hopper and feed pipe,

I. wherein hopper comprises at least one external weights measurement subsystem for controlling supplemental stages and charging stage and for distribute at least one lower openings of dicarboxylic acids powder during the charging stage, wherein said at least one lower openings is placed in the top of feed pipe;

Ii. wherein feed pipe receives dicarboxylic acids powder, and transmits dicarboxylic acids powder by least one rotating screw through outlet;

B. direct insertion disperser, it has the first import of being connected with the outlet of feed pipe, for the first feed stream of introducing diamines to form the second import of dispersion, and dispersion outlet;

C. storage tank, it is for storing dispersion at the temperature between 50 DEG C and 60 DEG C, and wherein said storage tank comprises with dispersion outlet and is connected the recirculation circuit with reception dispersion; And

D. single continuous stirred tank reactor, it is for receiving the part for dispersion of storage and the second feed stream of diamines to produce nylon salt solution.

2. process unit according to claim 1, is characterized in that, described recirculation circuit comprises outside displacer, and described outside displacer receives the dispersion as guiding stream.

3. process unit according to claim 1, is characterized in that, described recirculation circuit comprises one or more heaters, receives dispersion in the downstream of described one or more heaters.

4. process unit according to claim 1, is characterized in that, described recirculation circuit comprises one or more heater pumps.

5. process unit according to claim 1, is characterized in that, described recirculation circuit is not connected to measure the dispersion of storage with any analyzer.

6. process unit according to claim 1, is characterized in that, described recirculation circuit is expelled in storage tank by one or more internal spray blenders.

7. process unit according to claim 6, is characterized in that, described one or more internal spray blenders are placed in between 0.3 meter and 1.5 meters of the bottom of described storage tank and locate.

8. process unit according to claim 1, it is characterized in that, described direct insertion disperser comprises inner chamber and the multiple blenders around described inner chamber, and described multiple blenders are for mixing to form dispersion by the first feed stream of dicarboxylic acids powder and diamines.

9. process unit according to claim 8, is characterized in that, discharges described dispersion by multiple agitators through outlet.

10. process unit according to claim 1, is characterized in that, described process unit further comprises the supply container with low valve, and during supplemental stages, described low valve is opened and dicarboxylic acids powder is transported to hopper.

11. process units according to claim 10, is characterized in that, described process unit further comprises transfer system, for dicarboxylic acids powder is sent to hopper from supply container.

12. process units according to claim 1, is characterized in that, described conduit comprises rotary table feeder.

13. process units according to claim 1, is characterized in that, described feed pipe further comprises one or more gas port, for nitrogen being introduced to dicarboxylic acids powder.

14. process units according to claim 1, is characterized in that, described feed pipe becomes the angle between 0 ° and 45 ° with direct insertion disperser downwards.

15. process units according to claim 1, is characterized in that, described process unit further comprises the pipeline for nylon salt solution is directly passed into nylon salt storage tank from single continuous stirred tank reactor.