CN1745055A - Process for producing (meth)acrylic acid or (meth)acrylic ester - Google Patents
Process for producing (meth)acrylic acid or (meth)acrylic ester Download PDFInfo
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- CN1745055A CN1745055A CN 200480000595 CN200480000595A CN1745055A CN 1745055 A CN1745055 A CN 1745055A CN 200480000595 CN200480000595 CN 200480000595 CN 200480000595 A CN200480000595 A CN 200480000595A CN 1745055 A CN1745055 A CN 1745055A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
- C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/16—Fractionating columns in which vapour bubbles through liquid
- B01D3/22—Fractionating columns in which vapour bubbles through liquid with horizontal sieve plates or grids; Construction of sieve plates or grids
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/16—Fractionating columns in which vapour bubbles through liquid
- B01D3/22—Fractionating columns in which vapour bubbles through liquid with horizontal sieve plates or grids; Construction of sieve plates or grids
- B01D3/225—Dual-flow sieve trays
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
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Abstract
In the distillation purification of (meth)acrylic acid or a (meth)acrylic ester, attachment, deposition and accumulation of solid matter are prevented to thereby stably maintain a high recovery rate for (meth)acrylic acid or a (meth)acrylic ester, realizing stable continuous operation of the distillation column for a prolonged period of time. There is provided a method of distillation of a composition containing (meth)acrylic acid or a (meth)acrylic ester by means of a distillation column having multistage trays in its interior, wherein use is made of a distillation column packed with, as trays, corrugated-plate-type non-weir perforated plates each having a corrugated sectional configuration and multiple through-holes and flat-plate-type non-weir perforated plates each constituted of a flat plate having multiple through-holes.
Description
Technical field
The present invention relates to be used for the distillation process for purification of preparation (methyl) vinylformic acid or (methyl) acrylate.
And in this specification sheets, (methyl) vinylformic acid is the general name of vinylformic acid and methacrylic acid, is meant wherein either party or both sides.And (methyl) acrylic acid or the like is meant (methyl) vinylformic acid and by the general name of these acid with (methyl) acrylate of making of alcohol, also is meant wherein at least a.
Background technology
As everyone knows, as generating acrylic acid, the method for the catalytic vapor phase oxidation reaction that adopts propylene is arranged.In obtain acrylic acid this method by propylene oxidation, two kinds of technologies are arranged, a kind of technology be by the oxidation of propene to acrolein with by propenal to the oxidation of acrylic acid subordinate phase respectively in different reactors with the two-stage oxidizing technology of under different conditions, carrying out, another kind of technology is to adopt one section oxidation style direct oxidation to acrylic acid technology.
Fig. 1 adopts two-stage oxidizing technology to generate vinylformic acid for illustrating, and then is generated an example of the process picture sheet of acrylate by vinylformic acid that generates and alcohol reaction.Propylene, water vapour and air are fed into first reactor as unstripped gas, and then are fed into second reactor.In first reactor and second reactor, be filled with for example catalyzer such as molybdenum series catalyst.Unstripped gas is through first reactor and second reactor, and the propylene in the unstripped gas is become and contains acrylic acid gas by two-stage oxidizing.Make this contain vinylformic acid gas and contact with water, form acrylic acid aqueous solution,, extract, separate above-mentioned extraction solvent at the separated from solvent tower at extraction tower to wherein adding suitable extraction solvent at the capture tower.
Then,, make crude acrylic acid, in rectifying tower, from this crude acrylic acid, isolate by product, obtain acrylic acid refined products thus at separated from acetic acid tower separating acetic acid.In addition, this vinylformic acid (refined products) is after esterification reaction tower is carried out esterification, through extraction tower and low boiling point component knockout tower, become the crude propylene acid esters, at rectifying tower separating by-products (high boiling point composition) from this crude propylene acid esters, thus, above-mentioned crude propylene acid esters becomes the refining thing of acrylate.In above-mentioned separated from solvent tower, separated from acetic acid tower, low boiling point component knockout tower and rectifying tower, the composition that contains vinylformic acid or acrylate is distilled.
And, because of the kind difference of acrylate, also pass through this operation sometimes as Fig. 2.At this moment, by product obtains as the tower bottoms of vinylformic acid knockout tower.
In acrylate preparation technology shown in Figure 2, respectively vinylformic acid, alcohol, acrylic acid, recovery alcohol are supplied to esterifier.In this esterifier, be filled with catalyzer such as strong acid ion exchange resin.The esterification reaction mixture of the formations such as generation ester, unreacted acrylic acid, unreacting alcohol and generation water of taking out from this reactor supplies to the vinylformic acid knockout tower.
Extract liquid at the bottom of the tower that contains unreacted acrylic acid at the bottom of the tower of this vinylformic acid knockout tower out.The part of liquid circulates to esterifier at the bottom of the tower.The part of liquid supplies to high boiling point component separating tower at the bottom of the above-mentioned tower, isolates the high boiling point composition at the bottom of tower.The high boiling point composition is supplied to high boiling point composition decomposition reactor (not shown) to be decomposed.Containing the valuable decomposition product that generates by decomposition is recycled in the technology.Position in institute's round-robin technology is according to processing condition and difference.High boiling point impurity such as polymkeric substance are removed and are discharged into outside the system from high boiling point composition decomposition reactor.
Distillate acrylate, unreacting alcohol and generation water from the cat head of aforesaid propylene acid separation column.The part of overhead product is recycled to the vinylformic acid knockout tower as phegma, and remaining supplies to extraction tower.Supply with the water of the pure usefulness of extraction to this extraction tower.Go out to contain the water supply of alcohol to pure recovery tower from tower bottom flow.Distillatory alcohol is recycled to esterifier.
Supply to the low boiling point component knockout tower from the effusive crude propylene acid esters of the cat head of extraction tower.In the low boiling point component knockout tower, extract low boiling point component out from this cat head, toward the technology internal recycle.Position in circulation technology is according to processing condition and difference.The crude propylene acid esters of removing low boiling point component supplies to treating tower.In treating tower, obtain highly purified acrylate from cat head.Be recycled in the technology because of containing a large amount of vinylformic acid in the liquid at the bottom of the tower.Position in circulation technology is according to processing condition and difference.In aforesaid propylene acid separation column, low boiling point component knockout tower and treating tower, the composition that contains vinylformic acid and acrylate is distilled.
In addition, in recent years,, also adopt the azeotropic separation method to replace the solvent extration that uses extraction solvent to carry out for acrylic acid from above-mentioned acrylic acid aqueous solution.In this azeotropic separation method, water is distilled for boil-off together dose, distillate the azeotropic mixture of water and azeotropic solvent, acrylic acid at the bottom of the tower from the cat head of azeotropic separation tower.
In addition, also can replace propylene and in the presence of catalyzer, carry out catalytic vapor phase oxidation reaction obtaining acrylic acid by using propane.Above-mentioned catalyzer uses for example Mo-V-Te system complex oxide catalyzer or Mo-V-Sb system complex oxide catalyzer etc.
In the occasion of methacrylic acid and methacrylic ester, use the iso-butylene or the trimethyl carbinol to replace propylene, make methacrylic acid treating thing and the refining thing of methacrylic ester through same oxidizing process and subsequent esterification technique with above-mentioned explanation.
In addition, method as preparation (methyl) acrylate (acrylate, methacrylic ester), also can adopt with acid etc. to make (methyl) acrylate of lower alcohol and higher alcohols carry out transesterification reaction the method for (methyl) acrylate of preparation higher alcohols as catalyzer.Thick (methyl) acrylate that this transesterification reaction obtains, through catalyst separating, concentrate, the operation of rectifying etc. makes refining (methyl) acrylate.
In the distillation process for refining of above-mentioned crude acrylic acid, crude methacrylic acid, crude propylene acid esters, crude methacrylic acid ester, in order to obtain rectification effect, generally adopt at the tray column of the various column plates of internal configuration or fill the packing tower of various fillers.
As column plate, there are bubble-cap formula column plate (bubble cap), uniflux tray, T type disc type valve tray, ballast tray, multiaperture-type column plate (sieve formula column plate), funnel-shaped column plate, corrugated plate dst not to have weir porous plate, flat no weir porous plate, deflector type column plate etc.
As filler, Raschig ring as ring packing, spiral ring, Pall ring etc. are arranged, as the Berl saddle packing of saddle type filler, the saddle packing (イ Application one ロ Star Network サ De Le) etc. of interlocking, as other filler, Goodloe packing, enlightening gram DNA releaxed circular DNA, MeMahon packing, vertical plate structured packing etc. are arranged.
The distillation process of (methyl) vinylformic acid or its ester is characterised in that, often contains the solid substance of polymkeric substance etc. in the process liquor in distillation process.(methyl) vinylformic acid and (methyl) acrylate are very easy polymeric materials.Therefore, in above-mentioned distillation process, polymerization be can suppress, nonetheless, acrylic acid dimer and other polymer material in process liquor, also often contained though in above-mentioned process liquor, add stopper.Because this solid substance also generates in distillation procedure, therefore general packing tower is not suitable for above-mentioned distillation process.In addition, in overflow pipe, generate solid substance easily.Therefore, in the preparation of (methyl) vinylformic acid or (methyl) acrylate, the preferred flat no weir porous plate that is used to constitute plate column (the public clear 49-15153 communique of reference example such as spy) that does not have overflow pipe that uses.
Flat no weir porous plate is by same plane peristome with above-mentioned communicating pores, so the steam that drops down onto the liquid of hypomere and rise to epimere from hypomere from epimere passes through peristome under identical conditions.Therefore, its port area can not all be used to allow liquid pass through, and owing to the effect of steam makes at ascent direction generation pressure therefore, have the shortcoming of the easy occlusion of openings of solid substance portion.Also known a kind of fine part of attempting the percentage of open area etc. by setting flat no weir porous plate makes commercial apparatus reach the technology of practicability, and (reference example such as spy open the 2000-300903 communique.)。But, still can not overcome the above-mentioned shortcoming that flat no weir porous plate is had basically.
Above-mentioned solid substance is also in the distillation purification operations, because (methyl) vinylformic acid or its ester are heated and newly separate out or generate.So, cause that these solid substances adhere to, pile up or are accumulated on the column plate of distillation tower inside and in the positions such as space of filler, thereby the pressure reduction between causing at the bottom of cat head and the tower rises, gas-to-liquid contact state deteriorating and then result in blockage etc.Its result not only makes the rate of recovery of purpose resultant reduce, and the problem of continuous operation of hindering stable distillation tower and so on is arranged.
Therefore, in (methyl) vinylformic acid, (methyl) acrylate both sides' preparation section, people wish to develop and had a kind ofly not only addressed the above problem, but also can stably obtain the distillation process for refining of the said products with the high rate of recovery.
Summary of the invention
The objective of the invention is to, the preparation method of a kind of (methyl) acrylic acid or the like is provided, this method is when the distillation of carrying out (methyl) vinylformic acid, (methyl) acrylate is refining, can prevent adhering to, pile up, accumulating of this solid substance, stably keep the high-recovery of (methyl) vinylformic acid, (methyl) acrylate, make distillation tower continuous operation steadily in the long term.
What present inventors had carried out studying intensively found that, satisfies defined terms by the structure that makes distillation tower inside, just can overcome these shortcomings, has so far finished the present invention.
Promptly, the present invention is that a kind of composition that will contain (methyl) vinylformic acid or (methyl) acrylate (following they are referred to as " (methyl) acrylic acid or the like ") that comprises carries out the distillatory operation with inner distillation tower with multistage column plate, from above-mentioned composition, (methyl) vinylformic acid or (methyl) acrylate are taken out, the method of preparation (methyl) vinylformic acid or (methyl) acrylate, in the method, as distillation tower, use a kind of cross-sectional shape that is provided with to be ripple type, corrugated plate dst with a plurality of communicating poress does not have the weir porous plate, and on flat board, have the distillation tower of the flat no weir porous plate of a plurality of communicating poress as column plate.
The simple declaration of accompanying drawing
Fig. 1 is the figure that routine vinylformic acid and acrylate preparation section are shown.
Fig. 2 is the figure that another routine acrylate preparation section is shown.
Fig. 3 illustrates to have the pattern sectional view that corrugated plate dst does not have the distillation tower of weir porous plate.
Fig. 4 is the pattern sectional view that the distillation tower with flat no weir porous plate is shown.
Fig. 5 is with the sectional view shown in the X amplification of Fig. 3.
Fig. 6 is with the sectional view shown in the Y amplification of Fig. 4.
The preferred plan that is used to carry out an invention
Among the present invention, comprise that the composition that will contain (methyl) acrylic acid or the like carries out the distillatory operation with inner distillation tower with multistage column plate, takes out (methyl) acrylic acid or the like preparation (methyl) acrylic acid or the like from above-mentioned composition.
As the representative compounds of above-mentioned (methyl) acrylic acid or the like, can list (methyl) vinylformic acid and (methyl) esters of acrylic acid.As esters of acrylic acid, can list methyl acrylate, ethyl propenoate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, ethyl acrylate, 2-Hydroxy ethyl acrylate, vinylformic acid-2-hydroxy propyl ester, vinylformic acid methoxyl group ethyl ester etc.As methyl acrylic ester, can list that usefulness " methacrylic acid " replaces " vinylformic acid " of above-mentioned esters of acrylic acid and the compound that forms.
Among the present invention, in the scope of not damaging effect of the present invention, except above-mentioned distillation process, can also comprise other operations relevant with the preparation of (methyl) acrylic acid or the like.As this other operation, can list the operation that is used for preparation (methyl) acrylic acid or the like and carries out usually.
As the composition that contains (methyl) acrylic acid or the like, can use the composition that in the ordinary method of preparation (methyl) acrylic acid or the like, obtains.As this composition, can list the aqueous solution of (methyl) acrylic acid or the like itself, (methyl) acrylic acid or the like, be the solution etc. of (methyl) acrylic acid or the like of solvent with the organic solvent.As above-mentioned organic solvent, can use those be used for from the aqueous solution of (methyl) acrylic acid or the like extraction (methyl) acrylic acid or the like known extraction solvent, with the known azeotropic solvent of water azeotropic etc.
As the acrylic acid ordinary method of above-mentioned preparation (methyl), when being example, can list for example following (1)～(3) etc. with vinylformic acid.
(1) comprises the method for following operation: make propane, propylene and/or propenal carry out catalytic vapor phase oxidation, generate the oxidation operation that contains acrylic acid gas; The acrylic acid gas that contains that generates in the oxidation operation is contacted with water, vinylformic acid is made the capture operation that acrylic acid aqueous solution captures; From this acrylic acid aqueous solution, use suitable extraction solvent to extract acrylic acid extraction process; The operation of fractionation by distillation vinylformic acid and solvent from the extract that obtains; The refining acrylic acid operation that obtains of separating of distillation; With the high boiling point composition that contains stopper that uses in your (Micheal) affixture of the vinylformic acid Mick that obtains behind the refining step and each operation as raw material supplying to the decomposition reaction tower and reclaim the operation of valuable product; And, the valuable product that obtains is supplied to the operation that captures in any later operation of operation.
(2) comprise the method for following operation: make propane, propylene and/or propenal carry out catalytic vapor phase oxidation, generate the oxidation operation that contains acrylic acid gas; The acrylic acid gas that contains that generates in the oxidation operation is contacted with water, vinylformic acid is made the capture operation that acrylic acid aqueous solution captures; This acrylic acid aqueous solution is being distilled in the azeotropic separation tower in the presence of the azeotropic solvent, taking out the azeotropic separation operation of crude acrylic acid at the bottom of the tower; From the crude acrylic acid that obtains, remove the separated from acetic acid operation that acetate is used by distillation; Further remove the refining step of high boiling point composition the acrylic acid composition after isolating acetate by distillation; With the high boiling point composition that contains stopper that uses in your affixture of the vinylformic acid Mick that obtains behind the refining step and each operation as raw material supplying to the decomposition reaction tower and reclaim the operation of valuable product; And, the valuable product that obtains is supplied to the operation that captures in any later operation of operation.
(3) comprise the method for following operation: make propane, propylene and/or propenal carry out catalytic vapor phase oxidation, generate the oxidation operation that contains acrylic acid gas; The acrylic acid gas that contains that generates in the oxidation operation is contacted with organic solvent, vinylformic acid is made the vinylformic acid organic solvent solution capture, remove simultaneously anhydrate, the capture/separation circuit of acetate etc.; From this vinylformic acid organic solvent solution, take out acrylic acid separation circuit by distillation; With the high boiling point composition that contains your affixture of stopper, organic solvent and vinylformic acid Mick that uses in each operation as raw material supplying to the decomposition reaction tower and reclaim the operation of valuable product; The valuable product that obtains is supplied to operation in any later operation of capture/separation circuit; And, the part of organic solvent is carried out the purified operation.
Ordinary method as preparation (methyl) acrylate, when being example with the acrylate, for example can list, with organic acid or cationic ion exchange resin etc. as catalyzer, the spissated unit operation of crude propylene acid esters liquid that makes the esterification operation of vinylformic acid and alcohol reaction and carry out reaction being obtained as being used for, comprise extract, the method for evaporation, distillatory refining step.As raw material propylene acid, can use the vinylformic acid of the employing method that for example above-mentioned (1)～(3) illustrate preparation.
In each unit operation, wait suitable selected according to the kind of employed catalyzer in the raw material ratio of the vinylformic acid of esterification and alcohol, the esterification or raw material, byproduct of reaction, esters of acrylic acid rerum natura separately.Through each unit operation, in treating tower, obtain the acrylate goods.
Contain esters of acrylic acid, β-acryloxy propionic ester class, β-alkoxyl propionic ester class, ethylene lactic acid ester class at the bottom of the tower for the treatment of tower in the liquid and be your affixture of Mick of main component.Supply to the decomposition reaction tower by the high boiling point composition that contains stopper that will use in liquid at the bottom of the above-mentioned tower and/or each operation, perhaps turn back in the technology to reclaim valuable product.
Kind according to alcohol, with vinylformic acid, acrylic acid dimer (hereinafter referred to as dipolymer), vinylformic acid trimer (hereinafter referred to as trimer), β-alkoxypropan acids, β-alkoxyl propionic ester class is main component, the high boiling point composition that contains stopper that uses in the preparation section also often obtains in any operation of each unit operation from esterification operation or above-mentioned refining step.For this high boiling point composition, also it is supplied to the decomposition reaction tower to reclaim valuable product as containing your the high boiling point composition of affixture of Mick, valuable product also is fed in reaction process or the refining step sometimes.
You are meant in the preparation process of (methyl) acrylic acid or the like to have the compound of active methylene group and the compound that unsaturated carboxylic compound reacts and generated by affixture above-mentioned Mick.Mick that affixture when your affixture of the above-mentioned vinylformic acid or the Mick of acrylate is meant for example as preparation vinylformic acid can list dipolymer, trimer, vinylformic acid tetramer (hereinafter referred to as tetramer) etc.; Mick that affixture during as the preparation acrylate, can list that the alkyl ester of carbonatoms 2～8 or cycloalkyl ester etc. add on the aforesaid propylene acid esters and your affixture of the acrylic acid Mick that forms, your affixture of Mick of β-acryloxy propionic ester, alcohol can be listed particularly, the ester body, ethylene lactic acid, ethylene lactic acid ester class of β-alkoxyl propionic ester, dipolymer, trimer, tetramer, trimeric ester body, tetramer etc. can be listed particularly.
In addition, in the preparation process of (methyl) acrylic acid or the like, as mentioned above, produce polymkeric substance in the preparation process, use stopper usually in order to be suppressed at.
As stopper, can list vinylformic acid copper, dithiocarbamic acid copper, phenolic compound, phenothiazine compounds etc. particularly.
As dithiocarbamic acid copper, can list copper dialkyldithiocarbamates such as cupric dimethyldithiocarbamate, copper diethyl dithiocarbamate, dipropyl dithiocarbamic acid copper, copper dibutyldithiocarbamate; Cyclic alkylidene dithiocarbamic acid copper such as ethylene thiocarbamate copper, tetramethylene dithiocarbamic acid copper, pentamethylene dithiocarbamic acid copper, hexa-methylene dithiocarbamic acid copper; Ring-type oxygen such as oxygen diethylidene dithiocarbamic acid copper two alkylidene group dithiocarbamic acid copper etc.
As phenolic compound, can list Resorcinol, terephthaldehyde's phenol (メ ト キ ノ Application), pyrogallol, pyrocatechol, Resorcinol, phenol or cresols etc.
As phenothiazine compounds, can list thiodiphenylamine, two-(α-Jia Jibianji) thiodiphenylamine, 3,7-dioctyl thiodiphenylamine, two-(α-Er Jiajibianji) thiodiphenylamine etc.
Though in technology, also contain the material beyond the above-claimed cpd sometimes,, as long as its kind is to the preparation of (methyl) acrylic acid or the like and does not refiningly have a dysgenic material that just there is no particular limitation.
In above-mentioned distillation process, use to have corrugated plate dst and do not have weir porous plate and flat no weir porous plate distillation tower as column plate.Above-mentioned distillation process is so long as can distill the operation of the composition that contains (methyl) acrylic acid or the like, and just there is no particular limitation.As this operation, can list for example as described above, extraction process; Solvent and the isolating operation of vinylformic acid with extraction solvent etc.; The vinylformic acid that is separated is carried out the purified operation; The azeotropic separation operation; The separated from acetic acid operation; A part of purified operation with organic solvent; And the unit operation of extraction, distillation etc. etc.According to the present invention, in the system that relatively is easy to generate above-mentioned solid substance, for example in the higher system of the concentration of (methyl) acrylic acid or the like in above-mentioned composition, can obtain better effect, more particularly, when above-mentioned distillation process is the operation of refining (methyl) acrylic acid or the like, can obtain better effect.
Above-mentioned distillation tower, so long as corrugated plate dst can there be the distillation tower that weir porous plate and flat no weir porous plate are provided with as column plate, just there is no particular limitation.As this distillation tower, the distillation tower that can use tray column for example etc. generally in chemical factory, to use.The stage number that is provided with in the above-mentioned distillation tower (hop count) can be set aptly according to the various conditions such as kind of object material and column plate, in the occasion of distillation (methyl) acrylic acid or the like, and usually preferably 10～50.
Above-mentioned corrugated plate dst does not have the weir porous plate, as Fig. 3 and shown in Figure 5, is a kind of porous plate that for example is processed into corrugated plate shape, and it is that cross-sectional shape is the plate of wave mode, and has a plurality of communicating poress.Above-mentioned corrugated plate dst does not have the weir porous plate, and it is so long as a kind of porous plate that can make ventilation and logical liquid reach appropriate balance in the still-process of (methyl) acrylic acid or the like gets final product, but preference such as percentage of open area are 5～30% porous plate.
Corrugated plate dst does not have in the porous plate of weir, and any one that can be in the lateral parts of part, mountain or the paddy of the part on mountain, paddy is provided with communicating pores.And, there is not the cross-sectional shape of weir porous plate about corrugated plate dst, be called " mountain " connecting the upside of protuberance upper end with the center line of the intermediate point height of recess lower end, be called " paddy " at the downside of center line.In addition, " side " is meant from the face between top to the bottom of paddy on mountain.
In addition, above-mentioned " wave mode " is meant mountain in cross-sectional shape and paddy repeated shapes continuously, and is formed at the shape that becomes inclination from the top on mountain to the surface of the plate of the bottom of paddy.Above-mentioned " wave mode " can be for example to resemble the sinusoidal wave shape that is formed mountain and paddy by the successive curve, also can be for example as the shape that pulse wave is formed by the hypotenuse connection, the shape that is formed by the combination of alternate line.In addition, above-mentioned " wave mode " is to be repeated to constitute by the cell configuration that mountain and paddy constitute, and this cell configuration can be identical, also can be different.
Above-mentioned flat no weir porous plate such as Fig. 4 and shown in Figure 6 are the flat boards with a plurality of communicating poress.Above-mentioned flat no weir porous plate is so long as to make ventilation and logical liquid reach the porous plate of appropriate balance in the still-process of (methyl) acrylic acid or the like just passable, and preference such as percentage of open area are 5～30% porous plate.In addition, in Fig. 3～6, the solid arrow among the figure is represented the flow of vapor direction in the distillation tower, dotted arrow express liquid flow direction.
In the distillation procedure of (methyl) acrylic acid or the like, use flat no weir porous plate usually.In general, owing in the distillation tower of the no weir of use porous plate overflow pipe (ダ ウ Application カ マ one) is not set, therefore complete section area of distillation tower can be used in gas-to-liquid contact, thereby makes being uniformly dispersed of liquid.In addition, also has treatment capacity than bubble-cap formula column plate feature efficiently.
But as mentioned above, flat no weir porous plate is by same plane peristome with above-mentioned communicating pores.Therefore, as shown in Figure 6, the liquid under the downward paragraph of epimere with pass through communicating pores from hypomere inversely to the steam that epimere rises.Therefore, because port area is not all to be used for allowing liquid pass through, and be subjected to the pressure on ascent direction that causes by steam, so have the shortcoming that solid substance stops up communicating pores easily.This shortcoming can solve by aperture or percentage of open area are adjusted to a certain degree.
It is different with flat no weir porous plate that corrugated plate dst does not have the weir porous plate, and the former is not because the peristome of communicating pores is to be in same planely, so liquid mainly flows downward from the part of paddy, and steam then passes through from the part on mountain.Solid substance in the liquid focuses on the bottom of the part of paddy, is discharged to hypomere, and therefore, solid substance is difficult to sedimentation and accumulation.In addition, as shown in Figure 5, corrugated plate dst does not have in the communicating pores of weir porous plate, and vertically by communicating pores, steam then passes through communicating pores along the axis direction of communicating pores to liquid.Therefore, suppress the obstruction of the communicating pores that causes by solid substance on the structure easily.
In addition, by the processing of corrugated plate shape, the occasion in being arranged at same distillation tower, its surface-area can be bigger than flat no weir porous plate, also more communicating pores can be set.
And then even just in case solid substance stops up the communicating pores of the part of paddy, the communicating pores of the lateral parts that liquid also can be by mountain part and mountain or paddy falls, and therefore, compares with flat no weir porous plate, can make the ground steady running of distillation tower longer time.And, if open greatly a little than the aperture of the communicating pores of the part of the paddy that is easier to pass through, then can obtain better effect to solid substance.
In addition, even the communicating pores of paddy part is blocked, the communicating pores of lateral parts can be used for gas-to-liquid contact, and therefore, the dispersion of liquid keeps evenly.Utilize this characteristic, can solve the problems such as adhering to, pile up, accumulate of solid substance.
And then, contain in processing in the distillation of liquid of (methyl) acrylic acid or the like, find to form or accumulate the phenomenon of polymkeric substance at the column plate back side.Its one of the main reasons can list and is back to or increases attached to residence time of the liquid at the column plate back side etc.Because flat no weir porous plate is the back side (following) is planar, be difficult to fall attached to following liquid, so its residence time is elongated easily.
Corrugated plate dst does not have the weir porous plate because the shape of its structure makes its back side form and tilts, and thus, is present in the downward easily drippage of liquid at the column plate back side, and this is the major cause that can be avoided above-mentioned shortcoming.
In addition, corrugated plate dst does not have the weir porous plate and flat no weir porous plate is same, and structure is very simple, therefore, has the very cheap advantage of construction cost of the manufacturing cost, setup fee etc. of distillation tower.
So, in the porous plate of flat no weir, for the solid substance that makes generation falls, suppress the generation of the solid substance in the distillation tower, must make aperture ratio bigger, and not have in the porous plate of weir, compare with flat no weir porous plate at corrugated plate dst, in order to suppress the generation of the solid substance in the distillation tower, do not need hole diameter enlargement.
In addition, in the porous plate of no weir, become well though reduce the distillatory effect (plate efficiency) that the aperture can make each piece not have the weir porous plate, the pressure reduction that each piece does not have the weir porous plate becomes big.Its result, the overall pressure reduction (pressure difference at the bottom of cat head and the tower) of distillation tower increases, and the increased pressure of tower bottom makes (boiling point increases) temperature of tower bottom rise thus, thereby the generation of solid substance is increased.
The invention is characterized in, carry out in the purified method in that (methyl) vinylformic acid and/or (methyl) acrylate are imported distillation tower, as above-mentioned distillation tower, it is inner use corrugated plate dst do not have weir porous plate and flat no weir porous plate the two.
Among the present invention, by be provided with the corrugated plate dst that can reduce the communicating pores aperture do not have the weir porous plate and from prevent to stop up viewpoint consider to be necessary to make the bigger flat no weir porous plate of communicating pores aperture ratio the two, can reach effective distillation (methyl) acrylic acid or the like at least, prevent that pressure reduction at the bottom of distillation tower cat head and the tower from rising and prevent the purposes such as distillation tower inside obstruction that solid substance causes.
Corrugated plate dst does not have number being set and ratio being set of weir porous plate and flat no weir porous plate, can not have the aperture of communicating pores in the porous plate of weir, every pressure reduction that is produced, every with respect to settings that suit such as distillatory effects according to each.Among the present invention, corrugated plate dst does not have several ratios is set is preferably 1: 1 of weir porous plate and flat no weir porous plate～4: 1.If above-mentioned corrugated plate dst does not have the several ratio of being provided with of weir porous plate less than 1, when high-level efficiency distillatory viewpoint was selected the communicating pores aperture, the solid substance that produces on the porous plate of flat no weir often caused the continuous operation time of distillation tower to shorten.If above-mentioned corrugated plate dst does not have the several ratio of being provided with of weir porous plate greater than 4, then often cause the overall pressure reduction increase of distillation tower and the temperature of tower bottom to rise, therefore be easy to generate solid substance, thereby the continuous operation time of distillation tower shortens.
In distillation tower inside, corrugated plate dst does not have weir porous plate and flat no weir porous plate can each plot alternately configured, also can press the piece of defined respectively and count alternately configured, also can dispose by kind, and can dispose brokenly.Among the present invention, the porous plate of the hypomere setting in distillation tower inside is preferably corrugated plate dst is not had the weir porous plate.
At tower bottom, in reboiler,, make that liquid flies upward at the bottom of the tower that contains gas and solid substance simultaneously, thereby make solid substance easily attached to the back side of the column plate of foot owing to being caused the spittle by the gas that boiled.This solid substance is residual in the porous plate of flat no weir easily, but because corrugated plate dst does not have weir porous plate (as mentioned above) is to be made of the plate that tilts, so at column plate back side generation liquid-flow, thereby solid substance is washed.
In that being set continuously, the polylith corrugated plate dst do not have the occasion of weir porous plate, make that hypomere disposes across on the direction that the part of the mountain of waveform successive direction or ripple and paddy extends, liquid is preferred to the consideration of horizontal direction dispersive viewpoint to this distributing style in the distillation tower from improving, and special preferred vertical disposes across.
In addition, in the occasion that the flat no weir of polylith porous plate is set continuously, consider to horizontal direction dispersive viewpoint from improving in the distillation tower liquid, though can dispose the cross-sectional shape of the identical communicating pores of percentage of open area and the different flat no weir porous plate of configuration of communicating pores respectively at last hypomere.
Among the present invention, do not have the cross-sectional shape of weir porous plate about above-mentioned corrugated plate dst, the height of ripple is preferably 1/2～1/20 with respect to the ratio (height/wavelength of ripple) of wavelength.And " wavelength " be meant from the summit on mountain to the horizontal throw on the summit on adjacent mountain, according to the tower diameter of distillatory object material, distillation tower and distillation condition etc. and different, is preferably 20～6,000mm." height of ripple " be meant from the summit on mountain to the vertical range of the lower-most point of paddy, with distillation condition etc. and different, is preferably 10～300mm according to the tower diameter of distillatory object material, distillation tower.
No weir porous plate during distillation must make it often wetting by liquid.In case dry (state that does not just have stopper) just is easy to generate solid substance.If aforementioned proportion is greater than 1/2, then being trapped in corrugated plate dst does not have the degree of depth increase of the liquid above the porous plate of weir, the pressure reduction that causes every corrugated plate dst not have the weir porous plate becomes excessive, cause the overall pressure reduction of distillation tower to increase, column bottom temperature is risen, thereby solid substance takes place easily, the continuous operation time of distillation tower is shortened.If it is identical with flat no weir porous plate that aforementioned proportion less than 1/20, then becomes, the liquid-flow of wave mode part becomes very little, is difficult to remove the solid substance that is produced, and therefore, the continuous operation time of distillation tower is shortened.
Among the present invention, the communicating pores aperture that corrugated plate dst does not have a weir porous plate is preferably less than the communicating pores aperture of flat no weir porous plate.Specifically, the corrugated plate dst communicating pores aperture a that do not have a weir porous plate is preferably 1.1～3.0 with the ratio b/a of the communicating pores aperture b of flat no weir porous plate.If aforementioned proportion is less than 1.1, though then corrugated plate dst does not have the alleviation effects height of the pressure reduction of the distillation tower that the weir porous plate brings, in the porous plate of flat no weir, stop up easily, the continuous operation time of distillation tower is shortened.If aforementioned proportion is greater than 3, then the speed relative different of the gas that blows out from the communicating pores of two kinds of no weir porous plates increases, and the air-flow in the distillation tower is got muddled, and is easy to generate solid substance thus, so just often makes the continuous operation time shortening of distillation tower.
Do not have communicating pores in weir porous plate and the above-mentioned flat no weir porous plate about above-mentioned corrugated plate dst, it is circular that the shape of cross section of communicating pores (shape of peristome) is generally, but also can be non-circular for rectangle, ellipse, polygon etc.In addition, the shape of cross section of a communicating pores can be single shape, also can be changed to other shape by certain shape continuously.And for above-mentioned communicating pores, the vertical sectional shape of communicating pores is generally rectangle, but also can be following than other shapes such as the trapezoidal of the last length of side or wall clock shapes.
In addition, in a no weir porous plate, the communicating pores of identical cross-sectional shape can only be set, the communicating pores of multiple different cross section shape also can be set.And, in the no weir porous plate, can be by communicating pores be set evenly distributedly on the monoblock porous plate, also can by uneven distribution communicating pores (for example the central part at porous plate is provided with some communicating poress more, at the periphery of porous plate some communicating poress is set less) is set.
Above-mentioned corrugated plate dst does not have the communicating pores aperture of weir porous plate, is generally 10～40mm, yet preferred this scope of the present invention.In addition, the communicating pores aperture of above-mentioned flat no weir porous plate is preferably 10～50mm.Among the present invention, in these no weir porous plates, the communicating pores of same apertures can only be set, the communicating pores in multiple different apertures also can be set.
Above-mentioned distillation tower also can have above-mentioned no weir porous plate other structures in addition in the scope of not damaging effect of the present invention.As this other structures, can list traverse baffle that the stock liquid supplying opening place that for example is arranged in the distillation tower is used for making the stock liquid baffling of being supplied with, be used to prevent top board that the stock liquid of traverse baffle splashes upward, be used for the reboiler of the stock liquid heating that supplies to distillation tower, at various nozzles that liquid flow path disposes aptly, other column plates except that the porous plate of above-mentioned no weir and above-mentioned filler etc.
In the above-mentioned reboiler, can use those at the known reboiler that uses during liquid at the bottom of the heating distillation Tata.Above-mentioned reboiler generally is divided into occasion that is provided with and the occasion that is provided with outside tower in tower, among the present invention, preferably be provided with outside tower.Pattern as reboiler has no particular limits.Can list the various heat exchangers of liquid heating usefulness at the bottom of the tower of vertical fixed tube template, horizontal fixed tube template, U word cast, double cast, spiral type, square (angle Block ロ Star Network) type, template, thin film evaporation type etc. particularly.
Various structure materials in the above-mentioned distillation tower can be selected according to easily polymerizable compound and temperature condition thereof that need are handled, and there is no particular limitation among the present invention.For example, using as the easily polymerizable material in the preparation process of representative (methyl) vinylformic acid and (methyl) esters of acrylic acid, can use stainless steel-like, for example SUS304, SUS304L, SUS316, SUS316L, SUS317, SUS317L, SUS327; Perhaps the hastelloy class is also suitable in the present invention uses.Consider that from the viewpoint viewpoint of erosion resistance above-mentioned material is as long as select according to each corresponding liquid rerum natura.
[embodiment]
Below enumerate embodiment and comparative example is described more specifically the present invention.
＜embodiment 1 〉
Use diameter 1, the vacuum still of 000mm, distillation vinylformic acid.This vacuum still have be used to supply with distillation with the tower still of stock liquid, be used to feed the steam of liquid in the tower still that has been heated tower body, be used for condenser that the vapour condensation of top of tower discharge is used.
In above-mentioned tower still, be provided for heating the reboiler of the above-mentioned raw materials liquid of being supplied with.Above-mentioned tower body is a tray column.Above-mentioned tower body has the structure of 30 blocks of any porous plates that can be provided as column plate.
In the present embodiment, as above-mentioned column plate, the corrugated plate dst that adds up to 30 is set does not have weir porous plate and flat no weir porous plate.In the present embodiment, the porous plate group that the order of not having 4 of weir porous plates, 1 of flat no weir porous plate according to corrugated plate dst is disposed from bottom to top is as one group, and by from bottom to top series arrangement, configuration is as the no weir porous plate of column plate with 6 groups of this porous plate groups.That is, 30 sections no weir porous plates are set altogether in above-mentioned vacuum still.
In addition, the hop count of no weir porous plate (column plate) is 1～30 section by from bottom to top sequential counting.Do not have the weir porous plate as above-mentioned corrugated plate dst, use a kind ofly to have the aperture and do not have the weir porous plate as the corrugated plate dst in the hole of 20mm, it is that the height of 200mm, ripple is that the corrugated plate dst of 20mm does not have the weir porous plate that corrugated plate dst does not have wavelength in the cross-sectional shape of weir porous plate.As above-mentioned flat no weir porous plate, use a kind of flat no weir porous plate with aperture as the hole of 25mm.The percentage of open area (surface-area of the no weir porous plate when not forming communicating pores with respect to supposition, the ratio that port area is shared) that corrugated plate dst does not have the weir porous plate is 23%, and the percentage of open area of flat no weir porous plate is 23%.
In the present embodiment, use corrugated plate dst not have the porous plate of weir porous plate as the distillation tower foot.This porous plate of 30 sections (column plate) is equivalent to 9 sections of theoretical plate numbers.And, do not have in the porous plate of weir at above-mentioned corrugated plate dst, design according to the extending direction of mountain that can make waved plate and paddy orthogonal mode on porous plate with upper-lower position relation.
Use contains the acrylic acid aqueous solution (below be abbreviated as (A) liquid) of vinylformic acid 55%, acetate 1.5%, formaldehyde 0.3% and a small amount of formic acid as distillatory stock liquid by mass concentration.In addition, use toluene, use above-mentioned vacuum still to turn round as the dehydration distillation tower as azeotropic solvent.
During beginning, make distillation tower stable with toluene after, respectively on the 16th section column plate by per hour 1,100kg supplies with (A) liquid, per hour presses 3 on the 30th section column plate, 100kg supplies with toluene.Tower top pressure is controlled at 14.0kPa, from Resorcinol and the thiodiphenylamine of top of tower supply as stopper.The feed rate of these stoppers, according to the concentration of the stopper in tower bottoms, Resorcinol is that 800ppm, thiodiphenylamine are that 500ppm adjusts like that.At the bottom of tower, press per hour 500 liters of air supplies.
In decantor after the standing separation, azeotropic solvent all refluxes to distillation tower mutually, and water is extracted out with the distillate of the condenser condenses of cat head.The reboiler gauge pressure is the steam heating of 196kPa.Like this, making tower top pressure is 15.5kPa, and the temperature of liquid is 82 ℃ at the bottom of the tower, makes above-mentioned vacuum still continuous operation.In the running, the tower bottoms of extracting out at the bottom of the tower, except that vinylformic acid, form, contain acetate 2.3%, water 0.6%, toluene 15%, also contain micro-stopper in addition by quality.Experiment condition in the present embodiment and the results are shown in the table 1.
Experiment condition and the results are shown in the table 1.
The cat head of the distillation tower in the running and the pressure reduction at the bottom of the tower are 6.5kPa or below the 6.5kPa, do not rise continued running stably.Shut down after 3 months and when opening point is checked distillation tower, on the 2nd section column plate, find to have a spot of acrylate copolymer.
＜comparative example 1 〉
As shown in table 1, among the embodiment 1, column plate is all changed to flat no weir porous plate, in addition, the distillatory that dewaters similarly to Example 1 experiment.In the running, the composition of the tower bottoms of extracting out at the bottom of the tower is identical with embodiment 1.
Similarly to Example 1, process operation can stably continue to carry out, but the cat head of distillation tower and the pressure reduction at the bottom of the tower rise to 16kPa from 8.5kPa.Shut down after 3 months, during from opening point inspection distillation tower, on the 1st～5 section column plate, find a large amount of acrylate copolymer.
＜comparative example 2 〉
As shown in table 1, make the 1st and the 5th section to be flat no weir porous plate, and make the 2nd～4 section not have the weir porous plate for corrugated plate dst, more than the 6th section or the 6th section, to there be porous plate group that the order of 4 of weir porous plates, 1 of flat no weir porous plate disposes from bottom to up as one group according to corrugated plate dst, by with 5 groups of series arrangement of pressing from bottom to top of this porous plate group, except the porous plate of configuration as column plate, the distillatory that dewaters similarly to Example 1 experiment.In the running, the composition of the tower bottoms of extracting out at the bottom of the tower is identical with embodiment 1.
Similarly to Example 1, process operation can be stablized constantly and carry out, but the cat head of distillation tower and the pressure reduction at the bottom of the tower rise to 15kPa from 8.5kPa.Shut down after 3 months, during from opening point inspection distillation tower, a large amount of acrylate copolymer of discovery below the 0th section flat no weir porous plate.
＜embodiment 2 〉
In the present embodiment, as shown in table 1, to not have porous plate group that the order of 3 of weir porous plates, 2 of flat no weir porous plates disposes from bottom to up as one group according to corrugated plate dst, by with 6 groups of series arrangement from bottom to top of this porous plate group, configuration is as the porous plate of column plate.In addition, as flat no weir porous plate, use to have the hole of aperture as 30mm, percentage of open area is 27% flat no weir porous plate.In addition, in the present embodiment, the distillatory that dewaters similarly to Example 1 experiment.In the running, the composition of the tower bottoms of extracting out at the bottom of the tower is identical with embodiment 1.
Similarly to Example 1, the cat head of distillation tower and the pressure reduction at the bottom of the tower are 5.5kPa, do not rise continued running stably.Shut down after 3 months, during from opening point inspection distillation tower, on the 3rd and the 4th section column plate, find the acrylate copolymer of trace.
＜comparative example 3 〉
As shown in table 1, make the 1st～5th section to be flat no weir porous plate, more than the 6th section or the 6th section, to there be porous plate group that the order of 3 of weir porous plates, 2 of flat no weir porous plates disposes from bottom to up as one group according to corrugated plate dst, by with 5 groups of this porous plate groups by from bottom to top series arrangement, configuration is as the porous plate of column plate, and in addition, the distillatory that dewaters is similarly to Example 2 tested.In the running, the composition of the tower bottoms of extracting out at the bottom of the tower is identical with embodiment 2.
Similarly to Example 2, process operation can stably continue to carry out, but the cat head of distillation tower and the pressure reduction at the bottom of the tower rise to 15kPa from 5.5kPa.Shut down after 3 months, when opening point is checked distillation tower, on the 1st～4th section column plate and below find a large amount of acrylate copolymer all.
＜embodiment 3 〉
As shown in table 1, there is not the weir porous plate as above-mentioned corrugated plate dst, use that a kind of to have the aperture be that 24% corrugated plate dst does not have the weir porous plate as communicating pores, the percentage of open area of 25mm, wavelength in its cross-sectional shape is that the height of 400mm, ripple does not have the weir porous plate for the 30mm corrugated plate dst, as above-mentioned flat no weir porous plate, use a kind of communicating pores with aperture as 30mm, percentage of open area is 24% flat no weir porous plate, in addition, dewater similarly to Example 1 distillatory experiment.In the running, the composition of the tower bottoms of extracting out at the bottom of the tower is identical with embodiment 1.
Similarly to Example 1, the cat head of distillation tower and the pressure reduction at the bottom of the tower are 5.5kPa, do not rise continued running stably.Shut down after 3 months, during from opening point inspection distillation tower, do not find the polymerizing acrylic acid thing.
＜comparative example 4 〉
As shown in table 1, among the embodiment 3, column plate is all changed to flat no weir porous plate, in addition, the distillatory that dewaters similarly to Example 3 experiment.In the running, the composition of the tower bottoms of extracting out at the bottom of the tower similarly to Example 3.
Similarly to Example 3, running can stably continue to carry out, but the cat head of distillation tower and the pressure reduction at the bottom of the tower rise to 16kPa from 8.2kPa.Shut down after 3 months, when opening point is checked distillation tower, on the 1st～4th section column plate and below find a large amount of acrylate copolymer all.
＜embodiment 4 〉
As shown in table 1, make the 1st～20th section for corrugated plate dst does not have the weir porous plate, and make more than the 21st section or the 21st section and to be flat no weir porous plate, in addition, the distillatory that dewaters similarly to Example 3 experiment.In the running, the composition of the tower bottoms of extracting out at the bottom of the tower is identical with embodiment 3.
Similarly to Example 3, the cat head of distillation tower and the pressure reduction at the bottom of the tower are 5.5kPa, do not rise continued running stably.Shut down after 3 months, during from opening point inspection distillation tower, do not find the polymerizing acrylic acid thing.
Table 1
| Embodiment 1 | Comparative example 1 | Comparative example 2 | Embodiment 2 | Comparative example 3 | Embodiment 3 | Comparative example 4 | Embodiment 4 | |||
| Corrugated plate dst does not have the weir porous plate | The section of setting | 1-4，6-9， 11-14，16-19， 21-24，26-29 | --- | 2-4，6-9， 11-14，16-19， 21-24，26-29 | 1-3，6-8， 11-13，16-18， 21-23，26-28 | 6-8，11-13， 16-18，21-24， 26-29 | 1-4，6-9， 11-14，16-19， 21-24，26-29 | --- | 1-20 | |
| Aperture a (mm) | 20 | --- | 20 | 20 | 20 | 25 | --- | 25 | ||
| Wavelength c (mm) | 200 | --- | 200 | 200 | 200 | 400 | --- | 400 | ||
| The height d (mm) of ripple | 20 | --- | 20 | 20 | 20 | 30 | --- | 30 | ||
| d/c(-) | 0.1 | --- | 0.1 | 0.1 | 0.1 | 0.075 | --- | 0.075 | ||
| Flat no weir porous plate | The section of setting | 5，10，15，20， 25，30 | 1-30 | 1，5，10，15， 20，25，30 | 4，5，9，10，14， 15，19，20，24， 25，29，30 | 1-5，9，10，14， 15，19，20，24， 25，29，30 | 5，10，15，20， 25，30 | 1-30 | 21-30 | |
| Aperture b (mm) | 25 | 25 | 25 | 30 | 30 | 30 | 30 | 30 | ||
| b/a(-) | 1.25 | --- | 1.25 | 1.5 | 1.5 | 1 | --- | 1 | ||
| Tower top pressure (kPa) | 15.5 | 15.5 | 15.5 | 15.5 | 15.5 | 15.5 | 15.5 | 15.5 | ||
| Tower bottom pressure (kPa) | 22 | 24 | 22 | 21 | 21 | 21 | 24 | 21 | ||
| The temperature of liquid at the bottom of the tower (℃) | 82 | 89 | 82 | 80 | 80 | 80 | 88 | 80 | ||
| Runtime (moon) | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | ||
| Pressure reduction at the bottom of cat head and the tower | Initial stage (kPa) | 6.5 | 8.5 | 85 | 5.5 | 5.5 | 5.5 | 8.2 | 5.5 | |
| Before stopping (kPa) | 6.5 | 16 | 15 | 5.5 | 15 | 5.5 | 16 | 5.5 | ||
| Having or not of polymkeric substance | (on a small quantity) arranged | Have | (under the hypomere) arranged | Trace (the 3rd, 4 section) | Have | Do not have | Have | Do not have | ||
[utilizing on the industry possibility]
According to the present invention, has corrugated plate dst without weir porous plate and flat destilling tower distillation (methyl) acrylic compounds without the weir porous plate owing to use, therefore can reduce the overall pressure reduction of destilling tower, can prevent the solid contents such as polymer the adhering to, piling up and accumulating in destilling tower of (methyl) acrylic compounds, the high-recovery of (methyl) acrylic compounds can be stably kept, and the continuous operation of destilling tower can be in long-time, stably carried out.
In addition, among the present invention, if use corrugated plate dst without the weir porous plate as the hypomere in the destilling tower without the weir porous plate, then can prevent the obstruction that is caused by solid content in the destilling tower, consider to have better effect from preventing the viewpoint that the overall pressure reduction of destilling tower rises.
In addition, among the present invention, if make the corrugated plate dst that arranges in the destilling tower without the weir porous plate and flat be 1: 1～4: 1 without the several ratio of arranging of weir porous plate, so from preventing that the viewpoint that the overall pressure reduction of destilling tower rises from considering to have better effect.
In addition, among the present invention, if corrugated plate dst is not had in the cross-sectional shape of weir porous plate, the height of ripple is 1/2～1/20 with respect to the ratio (height/wavelength of ripple) of wavelength, then from reaching the long-term continuous operation of distillation tower and considering to have better effect owing to separation efficiency improves the viewpoint that reaches the purpose that reduces column plate piece number.
In addition, among the present invention, if the communicating pores aperture a that corrugated plate dst is not had a weir porous plate is set at the communicating pores aperture b less than flat no weir porous plate, so from reaching the long-term continuous operation of distillation tower and considering owing to separation efficiency improves the viewpoint that reaches the purpose that reduces column plate piece number, has better effect, if b/a is set at 1.1～3, then has further effect.
Claims (10)
1. the preparation method of (methyl) vinylformic acid or (methyl) acrylate, this method comprises that the composition that will contain (methyl) vinylformic acid or (methyl) acrylate carries out the distillatory operation with inner distillation tower with multistage column plate, and from above-mentioned composition, take out (methyl) vinylformic acid or (methyl) acrylate, it is characterized in that
As above-mentioned distillation tower, use to be equipped with to have a plurality of cross-sectional shapes and do not have the weir porous plate and on flat board, have the distillation tower of the flat no weir porous plate of a plurality of communicating poress as above-mentioned column plate as the corrugated plate dst of wave mode communicating pores.
2. the method described in the claim 1 is characterized in that, in the above-mentioned distillation process, distills (methyl) vinylformic acid or (methyl) acrylate refining.
3. the method described in the claim 1 or 2 is characterized in that, the porous plate of hypomere setting is that corrugated plate dst does not have the weir porous plate in the above-mentioned distillation tower.
4. the described method of each in the claim 1～3 is characterized in that, the number ratio that the corrugated plate dst that is provided with in the above-mentioned distillation tower does not have weir porous plate and flat no weir porous plate is 1: 1～4: 1.
5. the described method of each in the claim 1～4 is characterized in that, does not have in the cross-sectional shape of weir porous plate at above-mentioned corrugated plate dst, and the height of ripple is 1/2～1/20 with respect to the ratio (height/wavelength of ripple) of wavelength.
6. the described method of each in the claim 1～5 is characterized in that, above-mentioned corrugated plate dst does not have the communicating pores aperture of the communicating pores aperture of weir porous plate less than above-mentioned flat no weir porous plate.
7. the method described in the claim 6 is characterized in that, the communicating pores aperture b of above-mentioned flat no weir porous plate is 1.1～3 with respect to the ratio b/a that above-mentioned corrugated plate dst does not have the communicating pores aperture a of weir porous plate.
8. the described method of each in the claim 1～7 is characterized in that, (methyl) vinylformic acid in the above-mentioned composition is that the catalytic vapor phase oxidation reaction by propylene or iso-butylene makes.
9. the described method of each in the claim 1～8 is characterized in that, (methyl) vinylformic acid in the above-mentioned composition is the vinylformic acid that the catalytic vapor phase oxidation reaction by propane makes.
10. the described method of each in the claim 1～9 is characterized in that, (methyl) acrylate in the above-mentioned composition is to carry out esterification by (methyl) vinylformic acid by each the described method preparation in the claim 1～9 to obtain.
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| Application Number | Priority Date | Filing Date | Title |
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| JP2004159049A JP2005336122A (en) | 2004-05-28 | 2004-05-28 | Method for producing (meth)acrylic acid or (meth)acrylic acid ester |
| JP159049/2004 | 2004-05-28 |
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| CN110935188A (en) * | 2019-12-18 | 2020-03-31 | 万华化学集团股份有限公司 | Continuous rectification separation method and device for hydroxyethyl (meth) acrylate crude product |
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| JP6135565B2 (en) * | 2014-03-17 | 2017-05-31 | 三菱化学株式会社 | Method for producing (meth) acrylic acid |
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| JP2000281617A (en) * | 1999-01-29 | 2000-10-10 | Mitsubishi Chemicals Corp | Purification of acrylic acid |
| DE60035141T2 (en) * | 1999-02-18 | 2008-02-14 | Nippon Shokubai Co., Ltd. | Perforated bottom without drain, column with perforated bottom without drain and process for distillation |
| JP3992896B2 (en) * | 1999-02-18 | 2007-10-17 | 株式会社日本触媒 | Non-weired perforated plate, non-weired perforated plate tower, and distillation method |
| JP2003033601A (en) * | 2001-07-23 | 2003-02-04 | Nippon Shokubai Co Ltd | Perforated plate tower with no weir |
| CN1260196C (en) * | 2001-10-09 | 2006-06-21 | 三菱化学株式会社 | Process for producing (meth)acrylic acids and process for distilling the same |
| JP2004130232A (en) * | 2002-10-10 | 2004-04-30 | Mitsubishi Chemicals Corp | Distillation column |
-
2004
- 2004-05-28 JP JP2004159049A patent/JP2005336122A/en active Pending
- 2004-10-21 WO PCT/JP2004/015610 patent/WO2005115963A1/en active Application Filing
- 2004-10-21 CN CNB2004800005955A patent/CN100427451C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108421379A (en) * | 2018-05-17 | 2018-08-21 | 大连铭晟环保设备有限公司 | Desulphurization denitration gas wash tower nethike embrane splinter device and desulphurization denitration gas wash tower |
| CN108421379B (en) * | 2018-05-17 | 2024-05-28 | 大连铭晟环保设备有限公司 | Desulfurization and denitrification dedusting tower omentum splashing device and desulfurization and denitrification dedusting tower |
| CN110935188A (en) * | 2019-12-18 | 2020-03-31 | 万华化学集团股份有限公司 | Continuous rectification separation method and device for hydroxyethyl (meth) acrylate crude product |
| CN110935188B (en) * | 2019-12-18 | 2021-10-22 | 万华化学集团股份有限公司 | Continuous rectification separation method and device for hydroxyethyl (meth) acrylate crude product |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2005115963A1 (en) | 2005-12-08 |
| CN100427451C (en) | 2008-10-22 |
| JP2005336122A (en) | 2005-12-08 |
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