CN203971888U

CN203971888U - For the production of the process unit of nylon salt solution

Info

Publication number: CN203971888U
Application number: CN201420173198.9U
Authority: CN
Inventors: 罗伯特·J·韦尔奇; 利恩·曼斯特; 保罗·诺米科斯
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: 2014-12-03
Anticipated expiration: 2024-04-10
Also published as: TWM500622U

Abstract

The utility model discloses the process unit for the production of nylon salt solution that comprises weight-loss type feeder and continuous stirred tank reactor.Described process unit is for preparing nylon salt solution by dicarboxylic acid monomer and diamine monomer are fed to single continuous stirred tank reactor.Based on weight, the dicarboxylic acids powder of metering from weight-loss type feeder to reactor.Form continuously nylon salt solution, and it has the low rate of change of relative target pH value and/or target concentration of salt solution.Described nylon salt solution is directly delivered to storage tank, is discharging after continuous stirred tank reactor, do not carry out further monomer interpolation, the adjusting of pH value or salting liquid and regulate.

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 61/818,108 of submitting on May 1st, 2013, the full content of described application and disclose incorporated herein.

Technical field

The utility model relates to the feeder for dicarboxylic acids powder, and is particularly related to the process unit that comprises weight-loss type feeder and single continuous stirred tank reactor.

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 is produced and is obtained 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 method of use has realized mol balance, produces but a batch method is not suitable for large scale industry.In addition,, between salt production and polymerization period, realized mol balance by several different intake of multiple reactors and diamines.

It is H that United States Patent (USP) 2130947 (its entirety is incorporated in the utility model by reference) has been described molecular formula ₂nCH ₂rCH ₂nH ₂diamines and molecular formula be HOOCCH ₂r ' CH ₂the salting liquid of the dicarboxylic acids of COOH, wherein R and R ' are the bivalent hydrocarbon radical containing alkene and alkynes unsaturated bond not, and wherein R has the chain length of at least 2 carbon atoms.Measure the pH value of salting liquid, and determine its flex point.Salting liquid is filled with in reactor to form polyamide.

United States Patent (USP) discloses 2012/0046439 and has described the manufacture method of a kind of production for the manufacture of the diacid of polyamide and the solution of diamine salts.The method comprises mixes at least two kinds of diacid and at least one diamines according to the quality salinity between 40% and 70%, comprise, in first step, preparation is used a kind of diacid and a kind of diamines to prepare diacid/diamine mol ratio to be less than 1 diacid and the aqueous solution of diamines; In second step, regulate the value between the mol ratio to 0.9 and 1.1 of diacid/diamine, and by adding other diacid and optionally adding water and/or diamines fixes the mass concentration of salt.

United States Patent (USP) discloses 2010/0168375 salting liquid of having described a kind of diamines and diacid, more specifically, describe the concentrated solution of a kind of adipic acid hexamethylenediamine salt of knowing clearly, it is the useful initiation material for the production of polyamide, more specifically, it is the useful initiation material of producing PA66.Described solution can 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 0.9-1.1 by adding diamines, the preferably value of 0.99-1.01, and revise the mass concentration of described salt by optionally adding wherein water.

United States Patent (USP) 4233234 (its entirety is incorporated in the utility model by reference) has been described a kind of by specific alkane dicarboxylic acids and specific alkane diamines are reacted in the aqueous solution of the salt that will prepare, produces continuously the method for the aqueous solution of the salt of the alkane dicarboxylic acids of 6 to 12 carbon atoms and the alkane diamines of 6 to 12 carbon atoms.Described aqueous saline solution is circulated to the first Mixed Zone from the first Mixed Zone by transmission region and the second Mixed Zone, introduces liquid alkane diamines and alkane dicarboxyl aqueous acid between the first and second Mixed Zones.Introducing is less than the alkane diamines of equal parts, adds the liquid alkane diamines of surplus after the second Mixed Zone, and aqueous saline solution is removed from the first Mixed Zone with the speed of its formation.The salting liquid of preparation is for the production of nylon.

Polymer reactor is described in United States Patent (USP) 6995233,6169162,5674794 and 3893811.

Although made effort improving technique aspect realize target specification, for example, in nylon salt solution aspect suitable pH value, mol balance and/or salinity, but still there is challenge.Especially dicarboxylic acids (being more specifically adipic acid) is a kind of powder with variable particle size, and this causes the large variation 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.In order to solve the difficulty of the goal standard of realizing homogeneous in continuous process, art methods is added stoichiometric diamines by series reaction device.In addition, use a series of reactor can increase quantity, fund cost and the energy consumption of equipment.

Utility model content

In first embodiment, the utility model relates to the process unit for the production of nylon salt solution, it comprises: weight-loss type feeder, described weight-loss type feeder comprises hopper, feed pipe and conduit for being connected hopper and feed pipe, wherein said hopper comprises that at least one external weights measurement subsystem for controlling supplemental stages and charging stage, at least one lower openings come to distribute dicarboxylic acids powder in the charging stage, and valve is driven and be placed in the top of feed pipe in wherein said at least one bottom; Wherein feed pipe receives dicarboxylic acids powder, and carries dicarboxylic acids powder by least one rotating screw through outlet; And single continuous stirred tank reactor, comprise the first import being connected with the outlet of feed pipe, for introducing Part I, water or its mixture of diamines with one or more second imports of production nylon salt solution, and comprise sample loop and for introducing the recirculation circuit in crosspoint of Part II of diamines, wherein crosspoint is in the upstream of sample loop.The first import can be adjacent with one or more the second imports.Feed pipe can be arranged on conduit.This process unit can further comprise having the supply container that recharges valve, described in recharge valve, during supplemental stages, dicarboxylic acids powder be delivered to hopper.This process unit also can further comprise the conveyer belt for dicarboxylic acids powder is delivered to hopper from supply container.Described process unit can further comprise pneumatic transfer system, for dicarboxylic acids powder is written into supply container.Described feed pipe can further comprise the one or more gas port for nitrogen being introduced to dicarboxylic acids powder.Described sample loop can comprise the one or more analyzers in the group that is selected from pH meter, refractometer and combination thereof.Described conduit can comprise feeding screw.Described process unit can further comprise the pipeline for nylon salt solution is directly passed into storage container from the recirculation circuit of continuous stirred tank reactor, wherein said pipeline does not have any for introducing the import of additional monomers of the group that selects free dicarboxylic acids, diamines and constitute, and extra monomer is delivered to pipeline or enters storage container preventing.Described feed pipe can be downwards and continuous stirred tank reactor angled.Described process unit can further comprise the motor for driving at least one rotating screw.Described rotating screw can be the rotating screw of speed-changing rotation spiral or fixed speed.Described dicarboxylic acids can be adipic acid, and described diamines can be hexamethylene diamine.

In second embodiment, the utility model relates to the process unit for the production of nylon salt solution, it comprises weight-loss type feeder, described weight-loss type feeder comprises hopper, feed pipe and conduit for being connected hopper and feed pipe, wherein said hopper comprises that at least one is for controlling the external weights measurement subsystem of supplemental stages and charging stage, and for divide at least one lower openings of complex acid powder in the charging stage, wherein said at least one lower openings is placed in the top of feed pipe, and wherein feed pipe receives adipic acid powder, and carry adipic acid powder by least one rotating screw through outlet, and there is the first import of outlet that connects feed pipe, for introducing hexamethylene diamine, water and/or its mixture to form the continuous stirred tank reactor of the second import of nylon salt solution, wherein said continuous stirred tank reactor comprises single reactor.

Brief description of the drawings

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

Fig. 1 is according to the schematic diagram of the nylon salt productive method of solution of an embodiment of the present utility model.

Fig. 2 is according to the schematic diagram of the weight-loss type feeder for the production of nylon salt solution of an embodiment of the present utility model.

Fig. 3 is according to the schematic diagram of the single continuous stirred tank reactor for the production of nylon salt solution of an embodiment of the present utility model.

Fig. 4 is according to the profile of the single continuous stirred tank reactor for the production of nylon salt solution of an embodiment of the present utility model.

Fig. 5 is according to the schematic diagram of the nylon salt productive method of solution of an embodiment of the present utility model.

Fig. 6 is according to the schematic diagram of the process control for nylon salt productive method of solution of an embodiment of the present utility model.

Fig. 7 is according to the schematic diagram of the process control with secondary control for nylon salt productive method of solution of an embodiment of the present utility model.

Fig. 8 is according to the schematic diagram of the process control with three grades of controls for nylon salt solution methods of an embodiment of the present utility model.

Fig. 9 is according to the schematic diagram of the process control of the on-line pH value measurement data obtaining under laboratory condition for having of nylon salt solution methods of an embodiment of the present utility model.

Figure 10 is the schematic diagram for nylon 6,6 production methods according to an embodiment of the present utility model.

Figure 11-13 are for showing according to the chart of the feed-rate variation of the adipic acid from weight-loss type feeder 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 utility model relates to the process unit for producing continuously nylon salt solution, comprises weight-loss type feeder and continuous stirred tank reactor, as single continuous stirred tank reactor.Measure dicarboxylic acids powder by weight-loss type feeder and enter single continuous stirred tank reactor with diamines together with water.This process unit has advantageously used weight-loss type feeder in conjunction with single continuous stirred tank reactor, to form the nylon salt solution of homogeneous.Due to the low feed-rate variation rate of the dicarboxylic acids powder from weight-loss type feeder, this process unit is improvements over the prior art.This low feed-rate variation rate has been eliminated extra continuous stirred tank reactor to realize the needs of nylon salt solution (as homogeneous pH value and salinity) of homogeneous.Compared with the conventional method, this process unit has advantageously reduced equipment, energy consumption and fund cost.

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 lower than 5ppm); Arsenic (being less than 3ppm); And hydrocarbon-type oil (be less than 10ppm, or lower 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, and for example, buys as the concentrated solution of the diamines between 80 % by weight and 100 % by weight or between 92 % by weight and 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.

As described below, use term adipic acid (AA) and hexamethylene diamine (HMD) to represent dicarboxylic acids and diamines.But this method can also be applied to other dicarboxylic acids and other diamines of pointing out above.

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, in single reactor, realize target pH value, for example occur therein in the single continuous stirred tank reactor (continuous stirred tank reactor, CSTR) of the formation of nylon salt solution.In continuation method, advantageously use single 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.Therefore, for example, if target salinity is 60%, the nylon salt solution of homogeneous has the salinity variability between 59.5% and 60.5%, preferably the salinity variability between 59.9% and 60.1%.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.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.

In the time producing continuously nylon salt solution according to the utility model, the rate of change of the salinity of nylon salt solution is preferably very low, for example relatively target salinity in ± 0.5%, ± 0.3% in, ± 0.2% in or ± 0.1% in variation.For the purpose of this utility model, the rate of change of salinity refers to the average rate of change with respect to continued operation.Target salinity can change according to manufacturing location.

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 focuses on the mol ratio and the HMD concentration that regulate the AA:HMD in salting liquid with multiple reactors.This focuses on 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.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 charging 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 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 continuous method.Batch production will require significantly larger container and reactor.In addition, batch production cannot realize the throughput rate of realizing 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 extra monitoring, control and the adjusting to 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 solution methods 100 comprises adipic acid is fed to weight-loss type feeder 110 by pipeline 102, and the adipic acid charging 139 of its measure of production, passes into the AA charging 139 of described metering in continuous stirred tank reactor 140.In addition, water is by pipeline 103, and HMD forms water-based HMD solution by pipeline 104 combination in static mixer 105, and it is fed in continuous stirred tank reactor 140 through pipeline 106.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.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

aA powder feeder based on weight

In one embodiment, as shown in Figure 2, use weight-loss type feeder 110 that AA powder 102 is fed in continuous stirred tank reactor 140.Weight-loss type feeder 110 is measured AA powder 102 to produce the AA powder feed stream 139 with low variational feed rate, and the variation that can solve 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 and 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, and can 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 mechanical function part 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 other embodiments, conduit 119 can not have inner feeder 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 be dried puies forward blow 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 reactor 140, 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 reactor 140 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 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.

reactor

In one embodiment, the utility model comprises for the production of the reactor of nylon salt solution, comprising: for the production of the continuous stirred tank reactor of nylon salt solution, it comprises the first import for dicarboxylic acids powder being introduced to continuous stirred tank reactor; For the first diamines charging being introduced to the second import of continuous stirred tank reactor, wherein said the second import is adjacent with described the first import; Be fixed on one or more deflection plates of the interior wall of continuous stirred tank reactor; Extend through the shaft at continuous stirred tank reactor center, wherein said shaft comprises at least one upper blade and at least one lower blade; And recirculation circuit, comprise the crosspoint for the second diamines charging being introduced to pump and sample loop upstream; And for nylon salt solution is directly passed into the pipeline of storage container from the recirculation circuit of continuous stirred tank reactor, wherein said pipeline does not have any for introducing the import of additional monomers, additional monomers is delivered to described pipeline or enters storage container preventing, described monomer select free dicarboxylic acids, diamines with and composition thereof the group that forms, wherein reactor comprises single reactor.

As shown in Figure 3, in single continuous stirred tank reactor 140, be prepared into nylon salt solution.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.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 in the utility model, 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.

Reactor 140 can have the draw ratio between 1.5 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 minutes.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.

Usually, applicable continuous stirred tank reactor comprises that at least one monomer import introduces AA, HMD and/or water.Described import directly passes into the top of reactor.In some embodiments, can carry out charging monomer in liquid level with suction pipe.Can there are multiple imports, for each component is introduced to reaction medium.Fig. 3 has shown an exemplary continuous stirred tank reactor.As shown in Figure 3, there is AA import 145 and HMD import 146.Can introduce diamines with pure HMD or with the form of the aqueous solution 106, the described aqueous solution contains the HMD (for example containing the HMD between 30 % by weight and 45 % by weight) between 20 % by weight and 55 % by weight, and contains the water (for example containing the water between 55 % by weight and 70 % by weight) between 45 % by weight and 80 % by weight.Can introduce the aqueous solution 106 by import 146, described import 146 is adjacent with the import 145 of dicarboxylic acids powder 139.In one embodiment, import 146 can be from import 145 between 0.3m and 1m.The aqueous solution 106 can contribute to dissolve, and can partly dissolve the dicarboxylic acids powder that passes into reactor 140.Water can be introduced together with diamines.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.

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, and described 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 3, 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, regulates or 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 port 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, exist and vertically extend into and by the shaft 158 at reactor 140 center.Preferably, shaft 158 extends along the center line of reactor 140, but shaft 158 can pass through center in some embodiments.In optional embodiment, shaft can tilt.Under the prerequisite of the mixing that can realize ideal, also can use eccentric shaft.

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)

As shown in Figure 4, shown three pitches (triple-pitch) turbine assembly 161.Shaft 158 comprises at least one upper angled blade turbomachine 162 and at least one lower tilt blade turbine 163.In the turbine assembly 161 of three pitches, offset on inclined plane 164 ' preferred and lower tilt blade turbomachine 163, the inclined plane 164 of upper angled blade turbomachine 162.

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.

Be back to Fig. 3, 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.Water 132 is passed into maintain the efficiency of recovery tower 131 with minimum-rate.Calculate by the amount of the water of recovery tower 131 chargings, to keep target salinity, and regulate the charging of other water.Emptying gas 134 can be condensed to reclaim any water and monomer waste gas and can return through pipeline 133.The noncondensable gas that comprises nitrogen and air can be used as waste gas 135 and removes.In the time that recovery tower 131 is a vent condenser, recovery tower 131 can be used to reclaim waste gas and remove noncondensable gas.

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

As mentioned above, by HMD used the nylon salt solution being used to form with two positions in different part introducing methods, main HMD and compensation HMD.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 5, can for example, by comprise the variance control that carrys out further meticulous goal standard (target pH value) via the compensation HMD of pipeline 107 at 142 places, crosspoint.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 by weight, the AA powder of metering from weight-loss type feeder 110 to feed pipe, described feed pipe delivers into continuous stirred tank reactor 140 by the AA powder feed 139 of metering with the feed rate of low rate of change; Respectively the aqueous solution 106 and the water 103 of the Part I that comprises HMD104 are introduced to continuous stirred tank reactor 140, to form nylon salt solution; And introduce the Part II of HMD, for example enter the compensation HMD of nylon salt solution by pipeline 107.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; And regulate the feed rate of HMD and water in response to process control.Advantageously, can realize high throughput rate by continuous processing.In the time changing salt throughput rate, can regulate pro rata HMD feed rate along with the AA feed rate of the variation of discrete interval.Can be by changing the feed rate of main HMD charging or compensate HMD feed rate the feed rate that regulates HMD.One preferred embodiment in, the feed rate of adjustable compensation HMD107, and the feed rate of HMD104 or can be constant for the feed rate of water-based HMD solution feed 106 described in given salt throughput rate.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 or the feed rate of described water-based HMD solution feed 106, with realize target pH value and/or salinity.In other embodiments, can regulate HMD104 and compensation HMD107 the two feed rate or the feed rate of described water-based HMD solution feed 106, with the concentration of realize target pH value and/or salt.

Compensation HMD107 can have the HMD source identical with HMD104.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 HMD104 and the ratio that compensates HMD107 according to target pH and target salinity.The ratio of HMD104 and compensation HMD107 can be set by the feed rate model of total HMD as discussed herein.

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 target 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 compensation 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, do not have HMD to be added to recirculation circuit 141.Add compensation HMD107 to upstream that pH measures, to allow to comprise the pH value measurement that compensates 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.

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 multiple 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 change in ± 5% to realize AA powder feed rate by the unpredictability and the fluctuation that reduce AA powder feed rate with weight-loss type feeder, the utility model utilizes the FEEDFORWARD CONTROL (feed forward control) based on model, under the condition that is with or without feedback, realize 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 main HMD and compensation HMD.The feed rate of water comprises all water sources that pass into 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 continuous stirred 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.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.These conventional methods of result can be used FEEDBACK CONTROL, thereby requirement frequently regulates or is a batch method.But in the time measuring AA powder to 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 for controlling the method for continuous production of nylon salt solution, and it comprises: generate one for setting the model of target feed speed of dicarboxylic acids powder, to produce the nylon salt solution with target pH value; And by by weight, the dicarboxylic acids powder of metering from weight-loss type feeder to feed pipe controlled the feed-rate variation rate of dicarboxylic acids powder, and described feed pipe is delivered to dicarboxylic acids powder to enter single continuous stirred tank reactor with target feed speed; With the first feed rate, diamines is introduced to single continuous stirred tank reactor respectively, with the second feed rate, water is introduced to single continuous stirred tank reactor, the wherein said first and/or second feed rate is based on model; And from single continuous stirred tank reactor, withdraw from continuously nylon salt solution and directly enter storage tank, wherein, the nylon salt solution of withdrawing from has the pH value in target pH value ± 0.04.

In order further to illustrate according to process control scheme of the present utility model, Fig. 6 has shown a flow chart.In order to simplify, in Fig. 6, get rid of various pumps, recirculation circuit and heater.Fig. 6 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 6, 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 enter the flow of reactor 140 through pipeline 106 by feed-forward signal 213.Similarly, controller 113 sends to flowmeter valve 216 by feed-forward signal 215 and regulates the flow of HMD104 through pipeline 106 inflow reactors 140.By this feed-forward signal of model specification, with realize target pH value and target salinity.

In another embodiment, controller 113 sends to flowmeter valve (not shown) by feed-forward signal (not shown) and regulates the HMD aqueous solution 106 to enter the feed rate of reactor 140.Because feed-forward signal 213 and 215 is used to HMD and water to pass into reactor 140, there is no need to take the measurement of the water-based HMD solution 106 of any online or off-line.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 be determined by the HMD107 of main HMD104 and compensation the relative quantity of the HMD of charging.Regulate feed-forward signal 217, 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 6, 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 described in the utility model, when based on weight metering AA powder, the feed rate of AA powder can have low variability.This low variability provides reliable AA powder feed rate, has improved the ability of realize target pH value and target salinity, and has improved the ability that regulates the feed rate of HMD and water based on feedback signal.Therefore, in one embodiment, the utility model relates to the quantity-produced method for controlling nylon salt solution, comprising: generate the model of the target feed speed for setting dicarboxylic acids powder, to produce the nylon salt solution with target pH value; By by weight, the dicarboxylic acids powder of metering from weight-loss type feeder to feed pipe controlled the feed-rate variation rate of dicarboxylic acids powder, and dicarboxylic acids powder is delivered to single continuous stirred tank reactor by described feed pipe; With the first feed rate, diamines is introduced to single continuous stirred tank reactor respectively, with the second feed rate, water is introduced to single continuous stirred tank reactor, to produce the nylon salt solution with target pH value; Compensation diamines is introduced in the recirculation circuit of single continuous stirred tank reactor continuously with the 3rd feed rate; Detect the variation of the pH value of nylon salt solution with the on-line pH value measurement of introducing the nylon salt solution that compensates diamines downstream; And regulating the 3rd feed rate to produce nylon salt solution in response to the variation of pH value, described nylon salt solution has with respect to the variation in ± 0.04 of target pH value.

As shown in Figure 7, 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, due to the condition changing, 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 216 and 218 by holding wire 215 and 217.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 main HMD104 by flowmeter valve 216.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 213 of flowmeter valve 214.

Because the process of described formation nylon salt solution is continuous, therefore (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, by model also can with secondary control next regulate main HMD and water.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 can provide information or mass flowrate to controller 113.As shown in Figure 7, each flowmeter valve combines a flowmeter, preferably can measurement quality flow.Flowmeter 214 ' warp 213 ' provides information to controller 113.Flowmeter 216 ' provides and feeds back to controller 113 through holding wire 215 '.Flowmeter 218 ' provides and feeds back to controller 113 through holding wire 217 '.Can the information from flowmeter maintain integral production speed with these.

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 Fig. 3,5,6,7,8 and 9, 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.

Therefore, in one embodiment, the utility model relates to the quantity-produced method for controlling nylon salt solution, comprising: generate the model of the target feed speed for setting dicarboxylic acids powder, to produce the nylon salt solution with target pH value; By by weight, the dicarboxylic acids powder of metering from weight-loss type feeder to feed pipe controlled the feed-rate variation rate of dicarboxylic acids powder, and dicarboxylic acids powder is delivered to single continuous stirred tank reactor by described feed pipe; With the first feed rate, diamines is introduced to single continuous stirred tank reactor respectively, with the second feed rate, water is introduced to single continuous stirred tank reactor, to produce the nylon salt solution with target pH value; Compensation diamines is introduced in the recirculation circuit of single continuous stirred tank reactor continuously with the 3rd feed rate; Obtain the sample part of the nylon salt solution of introducing compensation diamines downstream; Dilution cooling described sample part are to form the nylon salt solution of the dilution with the temperature between concentration between 5% and 15% and 15 DEG C and 40 DEG C; Detect the variation of the pH value of the nylon salt solution of dilution with the on-line pH value measurement of introducing the nylon salt solution that compensates diamines downstream; And regulating the 3rd feed rate to produce nylon salt solution in response to the variation of pH value, described nylon salt solution has the pH value with respect to the variation in ± 0.04 of target pH value.As shown in Figure 9, 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 215 and 217, then regulate feed rate to flowmeter valve 216 and 218.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 213 of flowmeter valve 214.

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 Fig. 6,7 and 9, 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 215 and 217 that is connected to flowmeter valve 216 and 218.Under laboratory condition, off-line pH measures the ability can with pH value determination in ± 0.01 scope.

Therefore, in one embodiment, the utility model relates to the quantity-produced method for controlling nylon salt solution, comprising: generate the model of the target feed speed for setting dicarboxylic acids powder, to produce the nylon salt solution with target pH value; By by weight, the dicarboxylic acids powder of metering from weight-loss type feeder to feed pipe controlled the feed-rate variation rate of dicarboxylic acids powder, and dicarboxylic acids powder is delivered to single continuous stirred tank reactor by described feed pipe; With the first feed rate, diamines is introduced to single continuous stirred tank reactor respectively, with the second feed rate, water is introduced to single continuous stirred tank reactor, to produce the nylon salt solution with target pH value; Compensation diamines is introduced in the recirculation circuit of single continuous stirred tank reactor continuously with the 3rd feed rate; From introduce the nylon salt solution in compensation diamines downstream, shift out sample, for the off-line pH value measurement of the nylon salt solution of the aqueous solution at the temperature between 15 DEG C and 40 DEG C; Detect the deviation that on-line pH value is measured and off-line pH value is measured; Detect the pH value variation of nylon salt solution with the online pH measured value of the nylon salt solution in introducing devious compensation diamines downstream; And regulating the 3rd feed rate to produce nylon salt solution in response to the variation of pH value, described nylon salt solution has the pH value with respect to the variation in ± 0.04 of target pH value.

As shown in Figure 8, at least a portion of the nylon salt solution in described sampling line 153, by online pH meter 154, wherein obtains pH value measurement data and output 226 is delivered to controller 113.Sampling line 153 also can comprise that cooler (not shown) is with first cooling nylon salt solution before passing through pH meter 154.Shift out at least a portion of the nylon salt solution in sampling line 153 by pipeline 221, and measure with testing pH meter 222.Through pipeline 220, water is added in pipeline 221, to be diluted to specific concentration, and sample is cooled to target temperature subsequently, for example temperature between 15 DEG C to 40 DEG C or approximately 25 DEG C.In one embodiment, can dilute and cooling sample with cooling water.The pH value of the nylon salt solution in measurement line 221, and will export 226 sending value controllers 113.Then can by the part of the nylon salt solution of testing under experiment condition and test sample Returning pipe 155 and together with, and be back to reactor 140 through pipeline 224.In some embodiments, the part of the nylon salt solution of testing under laboratory condition can be processed to technique 100 by pipeline 223.

In order to reach temperature and the concentration of laboratory condition, can be by water be added to dilute and the cooling nylon salt solution example taking out from recirculation circuit through pipeline 220.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 pH analyzer can be used to solve the instrumental bias of online pH analyzer.For example, if target pH value is 7.500, online pH analyzer may report that pH value is 7.400, and off-line pH analyzer 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 10.

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.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 Figure 11, 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 12, the variation of feed rate can in 40 hours, be less than ± 3%.As shown in figure 13, 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

Preparing model is used for according to the nylon salt solution of continuity method production.Described nylon salt solution comprises water and adipic acid hexamethylene diamine salt.Described model is set to realize the salinity of 63% in nylon salt solution and to realize 7.500 target pH value.Determine the feed rate of AA based on the required production of nylon salt solution.Described salinity based on realizing and pH value, determine the feed rate of HMD and water.With low rate of change as described in Example 1, from powder uninstalling system, adipic acid is delivered to weight-loss type feeder.

By charging conduit instrument, the AA powder from weight-loss type feeder is directly provided to continuous stirred tank reactor, with 20 and 30nM ³/ hour between speed described charging conduit is carried out to nitrogen jet, to remove continuously the steam torrent generating in the effluent of feeder and purge reactor.

To determine by the salt feed rate based on from continuous stirred tank reactor salt reactor with for the DCS model of the base stock level of salt storage for the DCS set-point of the adipic acid feed rate of weight-loss type feeder.Measure salt feed rate by Coriolis (coriolis) mass flowmenter, and the time interval that can arrange based on inventory model regulate described salt feed rate to desired value, to replace direct use adipic acid feed rate.Conventionally, directly use adipic acid feed rate together with feeding back to the weight-loss type feeder feed rate feedback of DSC.

The HMD solution with 98% concentration is provided to direct insertion static mixer from pressure controlled HMD storage recirculation head.Use the measurement data of coriolis mass flowmeters and be input to DCS, the feed stream flow rate that uses the DCS adjusting of feedforward ratio control circuit to enter the HMD of static mixer, accurately to control based on AA powder feed rate the HMD that is added into continuous stirred tank reactor.This main HMD intake be the method require HMD intake approximately 95%.

By regulate the set point of DSC HMD ratio stream controller for the backfeed loop that compensates diamines valve output control, be output as medium range to maintain compensation HMD valve, to ensure that described valve is in continuous controlled range.

From pressure controlled deionized water supply head, deionized water is supplied to direct insertion static mixer.Use the measurement of coriolis mass flowmeters to be also input to DCS, use the DCS in feedforward rate control loop to regulate the flow velocity of the incoming flow of the deionized water that enters static mixer, accurately to control AA in continuous stirred tank reactor and the aqueous concentration of HMD.Use DSC to set deionized water feed rate to obtain the charge velocity of the required deionized water of the vent condenser of injecting reactor.

Direct insertion static mixer product stream 0.3 and 1.0m between adipic acid feed chute in directly pass into the top of CSTR, this special position is the dissolving of the adipic acid charging in order to contribute to enter.

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.The amount of being filled with of compensation HMD is about 5% of the total HMD being filled with 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.

CSTR comprises reactor tank and recirculation circuit.Described recirculation circuit comprises the first loop that a part for nylon salt solution is circulated to reactor, and by a part for nylon salt solution by pH is and the sampling line of Returning reactor subsequently directly.Described sampling line can comprise that cooler is with by nylon salt solution than the temperature that is present in the nylon salt solution in reactor cooling approximately 5 DEG C to 10 DEG C.Measure continuously the pH value of cooling nylon salt solution.Cooling nylon salt solution is back to reactor.PH measurement data is fed back to process control computer and regulates model.Described model adjusts HMD feed rate.

Take out a part for nylon salt solution, and under laboratory condition, measure subsequently the pH value of this part of nylon salt solution.In order to measure nylon salt solution under laboratory condition, water is by extremely approximately 9.5% concentration of nylon salt solution dilution.The nylon salt solution of dilution can be bathed and is cooled to approximately 25 DEG C by temperature.Under laboratory condition, measure the pH value of described nylon salt solution, and comparison object pH value and online pH measured value.Regulate subsequently described model, with the HMD feed rate of the low variation of relative target pH value of giving security.

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.The concentration input value that DCS uses the DCS of the continuous pairs comparison of online concentration measurement data to select, by the method for backfeed loop, regulates the DSC set point of deionized water ratio flow controller, to maintain concentration in target set point.

Reactor product is delivered to continuously salt storage by liquid level control tool by reactor.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 filter core of the value based on there being the minimum operating temperature that is 110 DEG C carries out the selection of filter.

Nylon salt 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 concentration overturns 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 of homogeneous.

embodiment 3

As embodiment 2 prepares nylon salt solution, except carry out on-line pH value measurement under laboratory condition; Approximately 9.5% concentration at the temperature of approximately 25 DEG C.

comparative example A

Honor is followed model and the method for embodiment 2, except replacing and use weight-loss type feeder with volume feeder.This model can not be realized, because the large variability of AA powder feed.The pH of nylon salt solution is greater than 0.120 with respect to the variation of target pH value.Nylon salt solution is the vicissitudinous crystallization temperature of tool and boiling temperature therefore.Therefore, poor pH value is controlled and has been caused significantly higher freezing point, and this requires high treatment temperature instrument to prevent the risk of crystallization.Because the boiling point changing, poor control also can cause the boiling of nylon salt solution, has therefore reduced the productive rate of nylon salt solution.

comparative example B

Follow model and the method for embodiment 2, except using the 2nd CSTR.Nylon salt solution withdraws from and passes into the 2nd CSTR from a CSTR.Between a CSTR and the 2nd CSTR, measure the pH value of nylon salt solution.In the 2nd CSTR, add extra HMD and/or water according to pH value and target pH value.From the 2nd CSTR, shift out nylon salt solution, and pH value determination.Described pH is relative, and target pH value has changed 0.120pH unit.Need extra CSTR further to regulate the pH of this nylon salt solution, this has caused the increase of fund and running cost.

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:

Weight-loss type feeder, comprises hopper, feed pipe, with the conduit for being connected hopper and feed pipe,

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

Wherein feed pipe receives dicarboxylic acids powder, and transmits dicarboxylic acids powder by least one rotating screw through outlet; And

Single continuous stirred tank reactor, comprise the first import of the outlet that connects feed pipe, for introduce diamines, water or its mixture with produce nylon salt solution one or more the second imports, comprise sample loop and for introducing the recirculation circuit in crosspoint of Part II of diamines, wherein said crosspoint is in sample loop upstream.

2. process unit according to claim 1, is characterized in that, described the first import is adjacent with one or more the second import.

3. process unit according to claim 1, is characterized in that, feed pipe is arranged on conduit.

4. process unit according to claim 1, is characterized in that, described process unit further comprises having the supply container that recharges valve, described in recharge valve, during supplemental stages, dicarboxylic acids powder be sent to hopper.

5. process unit according to claim 4, is characterized in that, described process unit further comprises the conveyer belt for dicarboxylic acids powder is delivered to hopper from supply container.

6. process unit according to claim 4, is characterized in that, described process unit further comprises the pneumatic transfer system for dicarboxylic acids powder being loaded into supply container.

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

8. process unit according to claim 1, is characterized in that, described sample loop comprises one or more analyzers, the group that described analyzer selects free pH meter, refractometer and constitutes.

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

10. process unit according to claim 1, it is characterized in that, described process unit further comprises the pipeline for nylon salt solution is delivered directly to storage container from the recirculation circuit of continuous stirred tank reactor, wherein said pipeline does not have any for introducing the import of additional monomers, extra monomer is delivered to described pipeline or enters storage container, the group that described extra monomer selects free dicarboxylic acids, diamines and constitutes preventing.

11. process units according to claim 1, is characterized in that, described feed pipe is downward and continuous stirred tank reactor is angled.

12. process units according to claim 1, is characterized in that, described process unit further comprises the motor for driving at least one rotating screw.

13. process units according to claim 12, is characterized in that, the rotating screw that described rotating screw is fixed speed.

14. process units according to claim 12, is characterized in that, the rotating screw that described rotating screw is speed change.

15. process units according to claim 1, is characterized in that, described dicarboxylic acids is that adipic acid and described diamines are hexamethylene diamine.