This application claims the benefit of priority based on December 6, Korea Patent Application No. 10-2016-0165309 and 04 December 2017 Date of Korea Patent Application No. 10-2017-0164979, 2016, of its Korea Patent Application everything described in the literature are included as part of the specification.

The present invention relates to a method for recovering (meth) acrylic acid.

[Background Art]

(Meth) acrylic acid is usually produced by compounds such as propane, propylene, (meth) arc lane in a manner that banung phase oxidation in the presence of a catalyst. For example, propane, propylene, etc. in the presence of a suitable catalyst in the reactor is converted to (meth) acrylic acid through (meth) acrolein by gas-phase oxidation reaction, in the rear half unggi (meth) O 3 rilsan, US banung propane or propylene, (meth) arc lane, organic by-products with an inert gas, carbon dioxide, water vapor and the banung a mixed gas (1) containing (acetate, low boiling point by-products. high boiling point by-products, etc.) can be obtained.

The (meth) acrylic acid-containing gas mixture (1) is a (meth) acrylic acid in contact with the absorbing solvent in an absorption tower 100, a (meth) acrylic acid is recovered as an aqueous solution. Then, the (meth) acrylic acid is insoluble gas stripping is recycled to the synthesis banung of (meth) acrylic acid, some of which are converted to the harmless gas incineration is discharged ¾. In addition, the (meth) acrylic acid aqueous solution is obtained by extraction, distillation and purified (meth) acrylic acid.

On the other hand, in order to improve such a (meth) acrylic acid recovery efficiency, the various methods for controlling the process conditions such as process or procedure has been proposed. A method for separating water and acetic acid from the (meth) acrylic acid aqueous solution obtained from that of the (meth) acrylic acid absorption tower 100, is known a method for azeotropic distillation by using a hydrophobic solvent in a distillation column. Alternatively, the (meth) acrylic acid aqueous solution

(Meth) using a hydrophobic solvent is supplied to the acrylic acid extraction column 200, the gain of the water content reduces the (meth) acrylic acid extract was 203 and the weight balance, by distilling the extract is known a method of reducing the energy consumption have.

However, (meth) from a known method for the recovery of acrylic acid

(Meth) absorber acid 100, to discharge the solution in a single stream to the lower portion, if the want to increase the concentration of the discharged (meth) acrylate solution, (meth) decreases the separation efficiency of the acrylic acid absorption tower 100 If that is, (meth) keep the concentration of the acid aqueous solution that is discharged to increase the separation efficiency, it is purified (or distillation) limit no choice but to increase the load in the subsequent purification (or distillation) step.

[Detailed Description of the Invention]

[SUMMARY]

The invention can further reduce energy use in all high (meth) yet, the purification process can ensure the recovery of acrylic acid. (Meth) to provide a method for recovering acrylic acid.

[Technical Solution]

The invention,

A) (meth) acrylic acid to create a step, by contacting the heunhap gas containing the organic by-products and water vapor (meth) acrylic acid and water from the absorber (meth) acrylic acid aqueous solution;

B) (meth) acrylic acid comprising: at the side of the absorption tower, discharge a (meth) acrylic acid aqueous solution of the first concentration;

C) a (meth) acrylic acid comprising: at the bottom of the absorption tower, discharge a (meth) acrylic acid aqueous solution of a second concentration;

B-1) comprising: in a discharge to the side, of the first concentration of (meth) acrylic acid aqueous solution of (meth) acrylic acid extraction column, is brought into contact with an extraction solvent comprising a hydrophobic organic solvent, extracting the (meth) acrylic acid; And

D) distilling the (meth) acrylic acid aqueous solution of the second concentration discharged from the (meth) acrylic acid extract, and said C) extraction step in step Bl) ,, through an azeotropic distillation process. (Meth) includes a step for obtaining acrylic acid.

To the first concentration, than the second concentration, and (meth) acrylic acid had a concentration is low, for satisfying the equation (1),

(Meth) provides a method for recovering acrylic acid.

Equation 1

Yl=a X Xl

In the equation (1),

Π is, the amount of extraction solvent used in the above B-1) stages,

A is, the extraction solvent ratio, above 2.5,

XI is, the first concentration (meth) the amount of water contained in the acid aqueous solution.

【Effects of the Invention】

(Meth) a method for recovering acrylic acid in accordance with the present invention, (meth) of different concentrations in the acrylic acid absorption Ram (meth) respectively discharging the aqueous acrylic acid solution, and subsequently, in a separate step (meth) high by extraction and distillation of acrylic acid (meth) allows the recovery and operation of the continuous process at a yet, the purification process can ensure the recovery of acrylic acid can remarkably reduce the energy consumption (meth) acrylic acid.

[Brief description of drawings]

1 and Fig. 2 is a process chart of the (meth) acrylic acid recovery method according to an embodiment of the present invention.

- specific information for carrying out the invention;

(Meth) acrylic acid recovery method of the present invention,

A) (meth) acrylic acid to create a step, by contacting the heunhap gas containing the organic by-products and water vapor (meth) acrylic acid and water from the absorber (meth) acrylic acid aqueous solution;

B) (meth) acrylic acid comprising: at the side of the absorption tower, discharge a (meth) acrylic acid aqueous solution of the first concentration;

C) a (meth) acrylic acid comprising: at the bottom of the absorption tower, discharge a (meth) acrylic acid aqueous solution of a second concentration;

B-1) comprising: in a discharge to the side, of the first concentration of (meth) acrylic acid aqueous solution of (meth) acrylic acid extraction column, is brought into contact with an extraction solvent comprising a hydrophobic organic solvent, extracting the (meth) acrylic acid; And

D) was distilled through a (meth) acrylic acid aqueous solution of the second concentration of the discharge in the (meth) acrylic acid extract, and said C) phase extracted from the B-1) step, azeotropic distillation, (meth) to give the acid a step, and

Wherein the first concentration, than the second concentration, and (meth) acrylic acid had a concentration is low, to satisfy the condition of equation (1).

Equation 1

Yl=aXXl

In the equation (1),

Y1 is, the amount of extraction solvent used in the B- 1) step,

A is, the extraction solvent ratio, above 2.5,

XI is a fish farming the water contained in the first concentration of (meth) acrylic acid aqueous solution.

In the present invention, the first, the term of the second, etc. are used to describe various components, the terms are used purposes only to distinguish one element from the other.

Moreover, terms that are used herein will be used to illustrate only exemplary embodiments and are not intended to limit the present invention. Expression in the singular number include a plural forms unless the context clearly indicates otherwise. In this specification, "it comprise", "comprising is" or "gajida" and terms are exemplary of characteristics, numbers, steps, components or geotyiji to be a combination thereof specify the presence, of one or more other characteristics or more or of numbers, steps, components, or the presence or possibility of combinations thereof and are not intended to preclude.

In the present invention, when each charging or element referred to as being formed "on" or "on top" of each of the layers or elements is meant to be formed on top of each chungdeul or elements direct the respective layers or elements, or else It means that the layer or element may be further formed on between the layers, the object, the substrate.

The present invention is to be described in detail to illustrate a bar, a specific embodiment and may have a variety of forms can be applied to various modifications. This, however, is by no means to restrict the invention to the particular form disclosed, it is to be understood as embracing all included in the spirit and scope of the present invention changes, equivalents and substitutes.

In this specification, the first, the term "(meth) acrylic acid" is used in the sense that collectively the acrylate (acryl ic acid), methacrylic acid (methacryl ic acid) or a common compound.

Further, the term "(meth) heunhap gas containing acrylic acid" shall collectively refer to heunhap gas that may be generated when manufacturing the (meth) acrylic acid by gas-phase oxidation banung. That is, the present, according to one embodiment of the invention, propane, propylene, butane, butylene i-, t- butylene, and (meth) arc in the lane of one or more compound ( "compound material") selected from the group consisting of as a method for the gas phase oxidation in the presence of a catalyst (meth) acrylic acid-containing gas mixture can be obtained. At this time, ' the (meth) acrylic acid-containing heunhap gas, (meth) acrylic acid, US banung material i compound, a (meth) arc the lane, an inert gas, carbon monoxide, carbon dioxide, water vapor and various organic by-products (acetate, low boiling point by-products and high boiling point It may include such by-products, etc.). Here, "low-boiling by-products, (l ight ends) or the term" high boiling point by-products "(heavies) is a busanmulwa one kinds that may be generated during the manufacturing and recovery process of the target (meth) acrylic acid to a molecular weight of (meth) than acrylic acid small or large is referred compounds.

Or less, to facilitate self-practice of this invention one of ordinary skill in the art, will be described in detail in the implementation examples of the present invention with reference to the accompanying drawings.

However, the invention is not be implemented in a number of different forms and limited only of embodiments described herein.

(Meth) acrylic acid recovery method of the invention, A) the (meth) acrylic acid to create a step, by contacting the heunhap gas containing the organic by-products and water vapor (meth) acrylic acid and water from the absorber (meth) acrylic acid aqueous solution; B) (meth) acrylic acid comprising: at the side of the absorption alarm, discharge the (meth) acrylic acid aqueous solution of the first concentration i ; C) a (meth) acrylic acid comprising: at the bottom of the absorption tower, discharge a (meth) acrylic acid aqueous solution of a second concentration; A B-1) (meth) acrylic acid aqueous solution of the first concentration to the discharge side (meth) acrylic acid in the extraction column, is brought into contact with an extraction solvent comprising a hydrophobic organic solvent. (Meth) extracting acrylic acid; And D) to the (meth) acrylic acid aqueous solution of the second nongbo discharged from the (meth) acrylic acid extract, and said C) phase extracted from the B-1) stage distillation through eu azeotropic distillation, (meth) to give the acid the first concentration comprising the step of, and has had the more the second concentration of (meth) acrylic acid concentration is low, to be conducted under the conditions satisfying expression (1).

Equation 1

Yl-a X Xl

In the equation (1),

Y1 is, the amount of extraction solvent used in the above B-1) stages,

a is, the extraction solvent ratio, 2.5 or more is ¾,

XI is, the first concentration (meth) the amount of water contained in the acid aqueous solution.

1 and Fig. 2 is a process chart of the (meth) acrylic acid recovery method according to an embodiment of the present invention.

1 and 2, the (meth) acrylic acid recovery method of the present invention. A)

(Meth) acrylic acid, comprising: making the organic by-products and heunhap gas (1) the (meth) (meth) contacting with water in the acrylic acid absorption tower 100, acid aqueous solution containing water vapor; B) (meth) acrylic acid comprising: at the side of the absorption tower 100, the discharge (meth) acrylic acid aqueous solution 103 of the first concentration (103); C) (meth) withdrawing the (meth) acrylic acid aqueous solution 102 of a second density in the bottom of the acrylic acid absorption tower 100, 102; In Bl) discharged to the side, the first concentration of (meth) acrylic acid aqueous solution 103, a (meth) acrylic acid extraction column 200, is contacted with an extraction solvent comprising a hydrophobic organic solvent, (meth) extracting acrylic acid the method comprising; And D) was distilled through a (meth) acrylic acid extract (203) and (meth) acrylic acid aqueous solution 102 of the second concentration discharged from the C) phase extracted from the B-1) step, azeotropic distillation ( 300), (meth) comprises a step 303 of obtaining the acrylic acid, and wherein the first concentration is, the more the second concentration of (meth) was the concentration of acrylic acid is low, under a condition satisfying the above formula (1) It is in progress.

According to the methods previously disclosed, (meth) acrylic acid aqueous solution

(Meth) to discharge in a single stream from the bottom of the acrylic acid absorption tower 100. (Meth) acrylic acid. And supplied to the extraction column 200, by using a hydrophobic solvent, (methoxycarbonyl. Root) to obtain an acrylic acid extract, 203, by distilling the extract, (meth) acrylic acid is recovered.

. However, the present inventors have found that the conventional (meth) the method for recovering acrylic acid. In the course of study, the (meth) which in order to improve the purification efficiency of the acrylic acid, discharged

(Meth) When If you want to increase the concentration of the acid aqueous solution, the separation efficiency of (meth) acrylic acid absorption tower 100 is lowered and, as low maintaining the concentration of the discharged (meth) acrylic acid aqueous solution in order to improve the separation efficiency, It confirmed that the further purification (or distillation) step tablet (or distillation), a problem occurs can not but increase in the load is.

Therefore, the low concentration stream that is the inventors chyesok research result of, each other, respectively discharged from the sides and bottom of the stream having a different density value (meth) acrylic acid absorption tower 100 and discharged from the side is in a separate extraction step after removing the water, put into the distillation process with a high concentration of the stream exiting the bottom, it is possible to reduce the even load unless lowering the separation efficiency in the subsequent distillation step, and confirmed that this can increase the energy efficiency, the present invention It was completed.

First, in the method for recovering the one (meth) according to an embodiment of acrylic acid, (meth) heunhap gas (1) to the (meth) acrylic acid and organic by-products and water vapor produced by the synthesis reaction of acrylic acid (meth) acrylate, in contact with water in an absorption tower 100, (meth) acrylic acid is to obtain a solution. As absorption step in used herein, (meth) acrylic acid as described above in the absorber 100

(Meth) refers to a process for obtaining an aqueous acrylic acid solution.

More specifically, performing the method of the (meth) Synthesis banung of acrylic acid oxidation banung at least one compound selected from the group consisting of propane, propylene, butane, iso-butylene, and (meth) arc the lane under the vapor phase catalytic It can be.

In this case, the gas-phase oxidation reaction can be carried out under gas phase oxidation half unggi banung and conditions of the conventional structure. It may be used that the catalyst also typically in the vapor phase oxidation banung, for example, be a catalyst or the like to be used as disclosed in the Republic of Korea Patent Registration No. 0349602 and No. No. 037 818.

(Meth) acrylic acid-containing heunhap produced by the gas phase oxidation banung. Gas (1), the desired product of (meth) acrylic acid addition, US banung starting materials, the intermediate, (meth) arc the lane, an inert gas, carbon dioxide. There may be water vapor, and various organic by-products (acetate, low boiling point by-products and high boiling point by-products, etc.) is included. Oh such (meth) acrylic acid aqueous solution of (meth) to the heunhap gas (1) containing an arc ralsan supplied to the (meth) acrylic acid absorption tower 100, by contact with an absorption solvent, water, (meth) acrylic acid is dissolved It can be obtained in the form of an aqueous solution.

Here, the (meth) acrylic acid type of the absorber 100 is deungheul contact efficiency of the gas mixture (1) and the absorption solvent ! Be determined in view of which, for example, (meth) acrylic acid absorption tapil of packed column type (packed column type), a (meth) acrylic acid absorption column, a tray type multi-stage (mul ti stage tray type) of. (Meth) acrylic acid absorption in the packed column-type towers are lashing ring (rashing r ing), polling (pal lr ing), birds (sadd e), gauze (gauze), the structured packing type (structured packing type) inside a filler such as might be applied.

And, in view of the efficiency of the absorption step, the heunhap gas (1) is a (meth) may be supplied to the lower part of the acrylic acid absorption tower 100, the absorption solvent containing water is a (meth) acrylic acid absorption tower 100 a it can be supplied to the upper portion.

The absorption solvent is able to contain water, such as deutmul, deionized water, and water circulating step is introduced from the other process (e.g., the extraction process 201 and / or the process water is recycled from the distillation step 352) It may contain. In addition, the absorbing solvent may be a small amount of organic by-products (e.g. acetic acid) itol is included which is introduced from the other process. However, it is preferable to be included (meth) considering absorption hyoeul of acrylic acid, as the (meth) acrylic acid absorption tower 100 or less is 15% by weight of organic by-product absorbing solvent (in particular the number of the cyclic process) to be supplied to the .

On the other hand, (meth) acrylic acid absorption tower 100 includes a (meth) taking into account the water content, such as according to the conditions ungchuk of acrylic acid and a saturated water vapor pressure, about 1 to about 1.5bar, or between about 1 and the internal pressure of approximately 1.3bar, and about 50 to about 100 ° C or from about 50 to about 80 ° may be operated under the inside of the silver is C eu

Meanwhile; Wherein: it made through the absorbing process, the (meth) acrylic " acid aqueous solution, (meth) acrylic acid absorption tower 100, there is increasing from the inside to the lower (meth) As addition to the absorption of acrylic acid higher the concentration, in general, ( (in the bottom of the interior 100) is formed with a concentration of about 70 to about .80% by weight. According to another aspect of the invention, this time, (meth acrylic acid absorption tower (10ϋ) meth) acrylic acid absorption tower to a side of the is discharged to a (meth) acrylic acid aqueous solution 102 of the second concentration of (meth) acrylic acid aqueous solution into the exhaust 103, the bottom has a relatively low concentration of the first concentration is the concentration at a relatively ^ nopeunge.

Specifically, the first concentration is preferably about 40 wt% or less, about 30 wt.%, Or, may be about 5 to about 30% by weight, wherein the second concentration is at least about 60% by weight, preferably, from about 70 weight> or more, or about 70 to about 95% by weight.

But not necessarily the present invention is not necessarily limited to this range,

(Meth) acrylic acid absorption tower 100, the temperature of the inside pressure and the like, (meth) to be obtained in the operating conditions of the process, and finally may be determined differently depending on the concentration of acrylic acid. Then, the top of the (meth) acrylic acid absorption tower 100 is biung condensable gases 101 the (meth) acrylic acid is degassed and discharged.

" At this time, the LA of the (meth) acrylic acid absorption tower 100 is also the side,

In the part of (meth) acrylic acid absorption tower 100 is interrupted side, that is, the top of the (meth) acrylic acid absorption tower 100 is zero, when you place the bottom of 100, downward from the top, which is equivalent to about 40 to about 99 any one point, and preferably it may be to sense the side portion in which a point corresponding to about 30 to about 70. The recovery method of the one embodiment the (meth) acrylic acid discharged from the side

(Meth) acrylic acid aqueous solution In a 103, a (meth) acrylic acid aqueous solution 102 discharged from the bottom, separately to each of the later-described process.

Meanwhile, according to one embodiment of the invention, the (meth) at least a portion of non-condensing gas 101 to be discharged to the upper portion of the acrylic acid absorption tower 100 is the organic by-products contained in biung condensable gas 101 (especially acetic acid) a it can be supplied to the step of re-recovered, and the remainder may be disposed of is supplied to the furnace waste gas (waste).

That is, according to one embodiment of the invention, contacting the biung condensable gas 101 and the absorption solvent, a step of recovering the acetic acid contained in the non-condensing gas 101 may be performed.

Contacting the biung condensable gas 101 and the absorbing solvent can be performed in nitric acid absorption tower (150). In this case, In order to effectively absorb acid, nitric acid absorption tower (150) is from about 1 to about 1.5bar pressure conditions, and preferably can be operated at about 1 naeja pressure conditions of ripening ^ 1.3bar, about 50 to about. 100 ° to C, preferably from about 50 to about 80 ° may be adjusted so that the silver is conducted at conditions of C. In addition, the specific operating conditions of the nitric acid absorption tower 150 may be in accordance with the Republic of Korea Patent Publication No. 2009-0041355.

At this time, the upper portion of the acetic acid absorption tower 150 to the lower portion of the acetic acid absorb the solvent 151 is supplied to, acetic acid absorption tower 150 for absorbing the acid may be an aqueous solution 152 is discharged containing acetic acid . In addition, the acetic acid-containing solution 152 is supplied to the upper portion of the (meth) acrylic acid absorption tower 100 can be used again as the absorption solvent. In addition, the acid may have, a non-condensable stripping gas 101 is circulated to the synthesis reaction step of (meth) acrylic acid can be re-used (recycled).

As above, when the immediately discharged from the side of the relatively low concentration of (meth) acrylic acid aqueous solution (103) (meth) acrylic acid absorption tower 100, since a relatively large amount of water (xi) is the same time the discharge, (meth) acrylic acid absorption tower (loo) amount (X2) of water to be discharged to the lower portion is inevitably reduced, thus, the (meth) acrylic acid absorption tower 100, the bottom has a high concentration of (meth) acrylic acid aqueous solution (102) it is possible to discharge.

Generally, in the (meth) acrylic acid absorption tower for discharging only a single stream,

The (meth) biung condensable gas when increase the concentration of (meth) acrylic acid discharged from the bottom of the acrylic acid absorption column, (meth) the absorption efficiency of acrylic acid absorption column is reduced, the (meth) discharged to the upper portion of the acrylic acid absorption tower, (meth) and to increase the content of the acrylic acid, whereby a (meth) acrylic acid in accordance with is the loss occurs.

However, the "To, in the case of just discharged from the side of the relatively low concentration of (meth) acrylic acid aqueous solution (103) (meth) acrylic acid absorption tower 100, a (meth) acrylic acid absorption tower 100 according to the present invention the absorption efficiency include, without little effect, (meth) acrylic acid absorption tower 100, the concentration of (meth) acrylic acid 102 is discharged from the lowermost be higher, and a (meth) acrylic acid aqueous solution with a low concentration emissions separately of ( 103) After all, it is easy to recover the function by a simple extraction procedure which will be described later eu

In accordance with one embodiment of the invention, the (meth) acrylic acid aqueous solution 103 of the first concentration is discharged to the side portion is, compared to the (meth) acrylic acid aqueous solution (102) of the second concentration discharged from the bottom, from about 10 weight ¾ > to preferably discharged at a rate of about 50% by weight, it may be desired to be conducted under the conditions satisfying the following expression (2).

Equation (2)

0.01 < X1/OQ+X2) < 0.7

In Equation 2,

XI is the liquid water and the amount of the first concentration of (meth) acrylic acid aqueous solution 103,

X2 is, the amount of water in a concentration of (meth) acrylic acid aqueous solution (102).

In this case, X1 + X2 is, as for the amount of the total water discharged from the absorption process to be used in the present invention, probably corresponding to the amount of the total water to be in the conventional process for discharging only the lower single stream in an absorption tower, discharged to the lower can.

In the first concentration of (meth) acrylic acid aqueous solution 103 and the second concentration of (meth) acrylic acid aqueous solution (102), with emission rates as described above, the relative amount of water discharged, the aforesaid range, and when conducted this process, the upper (meth) it is lost through biung condensable gas 101 discharged from it is possible to minimize the amount of acrylic acid. Preferably, the. Ratio of XI to the total amount of water discharged from the absorption step, can be from about 0.1 to about 0.7.

In addition, the relative amount of water discharged from the side and lower on the process steps for satisfying the above-mentioned range, such as (meth) subsequent extraction or distillation to obtain a (meth) acrylic acid from aqueous acrylic acid solution with high purity, the process load is reduced.

Specifically, for example, the side, that is, the first concentration of (meth) if the amount of water (XI) contained in the aqueous acrylic acid solution 103 is relatively being further increased, the subsequent extraction process for extracting the (meth) acrylic acid from which there is in the amount of the extracted organic solvent in need be increased, in this case, relatively., the distillation process. It is reduced, the use of an azeotropic solvent to be added to input, to reduce the processing load in the distillation process and, whereas the energy efficiency increases, reducing the efficiency of purification in the distillation step, thereby increasing the loss of acrylic acid.

On the other hand, the side, that is included in the first concentration of (meth) acrylic acid aqueous solution (103) ; : Water (XI) the amount of " case that less relatively, there is that in the extraction process for extracting the (meth) acrylic acid from which reduces the amount of extraction solvent in need, in this case, is additionally added in a distillation process to the amount of the azeotropic solvent is increased, to increase the acrylic acid purification efficiency of the distillation process, the loss of acrylic acid, but can be reduced, because it reduces the amount of water to be removed from the extraction column, the above-described advantageous effects of the present invention, that energy the downside is increased efficiency, reduced width may occur.

On the other hand, a method for recovering the one (meth) according to an embodiment of acrylic acid is characterized in that the first concentration of (meth) acrylic acid aqueous solution 103 is discharged to the side of the (meth) acrylic acid absorption tower 100, a (meth) acrylic acid extraction column the step of contacting the extraction solvent 302, containing a hydrophobic organic solvent in the (200) (meth) acrylic acid extract all further includes.

(Meth) acrylic acid in the extraction tower 200, the first concentration of (meth) acrylic acid

With an aqueous solution 103 is the extraction solvent 302 is in contact with, a substantial amount of (meth) acrylic acid is soluble (meth) acrylic acid extract (extract, 203) and the (meth) weight balance (raf f inate) lost significant amounts of acrylic acid may each be discharged.

And, in the above-mentioned (meth) acrylic acid extraction column 200, a relatively light merchant (meth) acrylic acid extract, 203 is obtained via the top outlet, the relative it is heavy merchant weight balance with the (meth) acrylic acid extraction column (200 ) it is discharged through the bottom outlet.

The weight balance, (meth) before being discharged from the acid extraction column 200, is present in the amount of the predetermined level value state to a lower value range of (meth) acrylic acid extraction column 200, some of which ( meth) being discharged to the bottom outlet of the acrylic acid extraction column 200, some of which can be recycled to the (meth) acrylic acid absorbing solvent (201) for absorbing (meth) acrylic acid to the (meth) acrylic acid absorption tower 100 have. '

In this way, a (meth) acrylic acid in the extraction container (200) (meth) via the method of the acrylic acid aqueous solution in contact with the extraction solvent, and most of the water contained in the (meth) acrylic acid aqueous solution can be removed. It can lower the processing load of the distillation process a subsequent process, it is possible improve the energy efficiency of the overall process.

Furthermore : by reducing the processing load of the distillation process, that can occur during the distillation , and the polymerization reaction of (meth) acrylic acid can be minimized, (meth) to further improve the recovery efficiency of acrylic acid.

On the other hand, the (meth) and the extraction solvent 302 is supplied to the acrylic acid extraction column 200 contains a hydrophobic organic solvent, also it contains other organic by-products, for example, a cyclic process is introduced from the other processes, which will be described later for every can.

Specifically, the extraction solvent is benzene (benzene), a toluene (toluene), and xylene (xylene), n- heptane (n-heptane), cycloheptane (cyc loheptane), cycloheptene (cyc loheptene), 1- heptene (l-heptene), ethyl-benzene (ethyl-benzene), methyl-cyclopentane nucleic acid (methyl-cyclohexane), n_ butyl acetate Theater (n-butyl acetate), isobutyl acetate (i sobutyl acetate), iso-butyl acrylate rate (i sobutyl acrylate), n- propyl acetate (n-propyl acetate), isopropyl acetate (i sopropyl acetate), methyl isobutyl ketone (methyl i sobutyl ketone), 2- methyl-1-heptene (2-methyl- heptene-l; ) , 6- methyl-1-heptene (6-methyl-l-heptene ), 4- methyl-1-heptene (4-methyl eu 1-heptene), 2-ethyl-1-haeksen (2 ethyl- 1-hexene), ethyl cyclopentane (ethylcyc lopentane), 2- methyl-1-haeksen (2-methyl-l-hexene ), 2, 3- dimethyl pentane (2, 3-di me t hy 1 pent ane ), 5-methyl-1-haeksen (5-me t hy 1 - 1-hexene), and isopropyl-t-butyl-ether (i sopropyl- butyl-ether) may comprise a hydrophobic organic solvent selected from the group consisting of one or more, and preferably renil benzene, a toluene or xylene .

In addition, the (meth) acrylic acid extraction column 200, liquid-If conventional extraction column in accordance with the liquid contact method, may be used without particular limitations.

For example, the reciprocating plate column in the Karr type (Karr type reciprocat ing plate column), the rotation一disk-shaped column (rotary一di sk contactor), Scheibel columns and Kuhni columns, spray extraction tower (spray extract ion tower), extracted filled tower or the like (ion extract packed tower), the pulse mogul column (pul sed packed column) '■ there. ■ through this extraction step, the (meth) acrylic acid: to the top of the extraction column 200 of (meth) acrylic acid extract solution 203 is withdrawn, it can be carried into the azeotropic distillation tower 300 through a feed line.

Then, the additive (meth) some, to sure.I'm recycled as described above, (meth) acrylic acid absorption tower 100, including acrylic acid extraction column to the lower portion of 200 is the weight balance has been discharged, the discharged weight balance increased water the (meth) acrylic acid can be used again to absorb the solvent 201. (Meth) acrylic acid absorbing solvent 201 to the top of the absorber if the tower used in the absorption solvents of the (meth) acrylic acid extraction column (meth) in the lower portion of 200, through just the separation of acrylic acid absorption tower 100 can be supplied, it is used in the distillation step described below, the azeotropic distillation column and then along with the azeotropic solvent contained in the upper top discharge liquid 304 discharged from, and sent to phase separation vessel 350, a phase separation, (meth) acrylic acid It may be supplied to the absorption solvent 352 in the absorption tower 100.

In this case, the extract contains not only the desired compound of (meth) acrylic acid, it may be included in the extraction solvent, water and organic by-products. According to the embodiment, in the stable operation it performed steady state, the extract has a (meth) acrylate, from about 2 to about 20% by weight, and the extraction solvent from about 75 to about 98 parts by weight of water from about 0.01 to about 2 parts by weight and the residual amount of organic It may contain byproducts.

Through the extraction step (meth) acrylic acid contained in the aqueous solution

Most of the water can be recovered in weight balance. Thus, as most of the water recovered from the extraction process, it is possible to reduce the operating pressure of the distillation step described below significantly lower energy consumption eu and, can be a distillation conditions mitigated by this, the (meth) acrylic acid in a distillation process it is secured with (meth) acrylic acid recovery efficiency improvement of the operation stability and the like to minimize the polymerization is possible.

Then, in the step of extracting the above-mentioned (meth) acrylic acid, to be conducted under a condition satisfying the equation (1).

Equation 1

Yl=a Xl

In the equation (1),

Y1 is, the amount of extraction solvent used in the above B-1) stages,

A is, the extraction solvent ratio, above 2.5,

XI is the liquid density 0.1 (meth) acrylic acid contained in the aqueous solution 103: the amount of water. A is a (meth) ratio, extraction solvent, referring to the amount of extraction solvent relative to the amount of water to be supplied to the acrylic acid extraction column 200, which may vary depending on the extraction solvent to be actually used, extraction. For efficiency, it can be seen about 2.5, preferably at least about 2.7 ·; eu - is preferably about 4.0 or less, can be about 3.5 or less. However, the present invention is necessarily i is not limited to the range, as described above, the efficiency of extracting the type of solvent, the extraction process used in the extraction process and will be described later taking into account the process load, such as in the distillation process also set different for have.

That is, the (meth) acrylic acid extraction column 200 is supplied to : the weight ratio of extraction solvent (Y1) in water (XI) in a first concentration of (meth) acrylic acid aqueous solution 103 is to be conducted in approximately 2.5 or more conditions, and , is preferably from preferably from about preferably from about 2.7 or more, and, about 4.0 or less, may be carried out at about 3.5 or less condition. Thus, while still maximizing, the extraction efficiency as a limited amount of the extraction solvent at the extraction step to a predetermined range, it is possible to operate the subsequent azeotropic distillation process stably.

In the extraction step, the (meth) the weight ratio of extraction solvent to the water in the acrylic acid aqueous solution of 2.5 is less than, and can increase the concentration of the (meth) acrylic acid in the weight balance, The higher the concentration of the (meth) acrylic acid in a weight balance , as a result, in the entire process, the (meth) acrylic acid may occur a problem that purification efficiency is lowered.

In addition, the (meth) the higher the weight ratio of extraction solvent to the water in the acrylic acid aqueous solution of (meth) acrylic acid extraction step (200) extraction efficiency may be improved, and a separate feed in the subsequent azeotropic distillation step as an azeotropic tower overhead in since that is to be reduced, the amount of the azeotropic solvent, the distillation efficiency is significantly reduced,

(Meth) acrylic acid increases in the loss.

Then, the weight balance which is obtained from the (meth) acrylic acid extraction column 200 may be the most can be made of water, is included it fails to be extracted (meth) acrylic acid and organic by-product portion.

More specifically, according to one embodiment of the invention, the weight balance, the concentration of about 10 parts by weight or less, or about 0. 1 to very little (meth) acrylic acid contains about 5% by weight is : It can be the absorption step and the extraction step there are (meth) acrylic acid losses in can be minimized.

And, the (meth) a method for recovering acrylic acid wherein the (meth) acrylic acid extract according to an embodiment of the invention: the 203 and the (meth) acrylic acid aqueous solution 102 of the second concentration discharged from the C) step by azeotropic distillation in the azeotropic distillation tower 300, and a step of obtaining a (meth) acrylic acid.

Solvents for use in the azeotropic distillation is preferably a hydrophobic solvent which does not form an azeotropic and azeotrope and can lead the water and acetic acid and the azeotropic, (meth) acrylic acid. In addition, the hydrophobic azeotropic solvents include (meth) lower boiling point than acrylic acid (for example, about 120 ° C or less, or about 10 to about 120 ° C, or from about 50 to about 120 ° preferably has a boiling point of C) Do.

Specifically, the hydrophobic azeotropic solvents benzene (benzene), toluene frame (toluene), and xylene (xylene), n- heptane (n- heptane), cycloheptane (cyc loheptane), cycloheptene (1 eye ohe tene), 1-heptene (1-hep tene), ethyl-benzene (et hy 1 -benzene), methyl-cyclopentane nucleic acid (methyl-cyc lohexane), n_-butyl acetate (n-butyl acetate), isobutyl acetate (i sobutyl acetate ), isobutyl acrylate (i sobutyl acryl ate), η- propyl acetate (n-propyl acetate), isopropyl

. Acetate (i sopropyl acetate), methyl isobutyl ketone (methyl i sobutyl ketone). 2-methyl-1-heptene eu (2-me t hy 1 - 1 - ene hep t), 6- methyl-1-heptene eu (6-me t hy 1-ene 1-hep t), 4- methyl-1- heptene (4-me t hy 1 - 1 - ene hep t), 2- ethyl-1-haeksen (2_e t hy 1 - 1-hexene), ethyl cyclopentane (et hy 1 eye 1 opent ane), 2- methyl - haeksen 1- (2-me t hy 1 - l-hexene), 2, 3- dimethyl pentane (2.3-d imethylpentane), 5- methyl-1-haeksen (5-methyl-l- hexene) and isopropyl - butyl-ether (i sopropyl-butyl-ether) may be daily for one or more selected from the group consisting of, preferably, benzene or toluene may be a renil, or xylene.

According to one embodiment of the invention, fed from the above-described extraction process, the (meth) acrylic acid extract 203 is fed to the azeotropic distillation tower 300 through a feed line.

At this time, in order to enable an efficient distillation can be made, the (meth) acrylic acid extract 203 is any one of the bottom from the top of the total number of stages of the azeotropic distillation tower 300, compared to approximately 25% to about 75%, more preferably Advantageously, it is preferred to be supplied in either one, which is equivalent to about 25 to about 50%.

(Meth) acrylic acid extract solution 203 supplied into the azeotropic distillation tower 300, (meth) there includes the extraction solvent (Y1) used in the acrylic acid and the previous extraction step, in view of the production efficiency, according to a continuous process , azeotropic ^ tying is preferably the same as the extraction solvent in the extraction process.

That is, when the azeotropic distillation tower 300 inside is properly heated, the (meth) by the extraction solvent (Y1) and the azeotropic distillation tower 300 in an azeotropic solvent (Y2) introduced from the upper part included in the acrylic acid extract, 203, azeotropic water supplied to the feed supply stage of the distillation column 300, and may be formed of an azeotropic distillation with acetic acid.

In accordance with one embodiment of the invention, the azeotropic distillation process, to may preferably be conducted under conditions that satisfy the equation (3).

[Equation 3]

Y=b x X2

In Equation (3),

Y is a positive, the azeotropic solvent used in D) steps,

b, and the ball BB,

X2 is, the second concentration (meth) the amount of water contained in the aqueous acrylic acid solution 102 eu previously (meth) years in extraction processes in the acid extraction column 200 is removed, most, because of the amount of water is very low containing the extract and water fed to the distillation column can be found equal the amount that was included in the second concentration of (meth) acrylic acid aqueous solution (102) (X2).

b, the ratio of the azeotropic say the amount of the azeotropic solvent to the amount of water (X2) to be supplied to the azeotropic distillation tower 300, which may be varied according to the azeotropic solvent to be actually used, to the efficiency of the azeotropic distillation, about 4 or more , preferably, about 5 or higher, more preferably from about 5.5 to about 8.5. However, the invention is not necessarily be limited to this range. , Efficiency and processing load of the type of the azeotropic solvent, the azeotropic distillation process using a distillation process, and may be set differently in consideration of the process load from the previous extraction process as described above.

Through such an azeotropic distillation process, and the (meth) acrylic acid extract (203) and said C) of the second concentration of (meth discharge step) acrylic acid aqueous solution (102) of the (meth) The remaining ingredients, except the acrylic acid are azeotropic solvent with the upper portion of the azeotropic distillation tower 300 : : a discharge being K304), (meth) acrylic acid is discharged to the lower portion 303, the upper discharge liquid 304 of yijjae, the azeotropic distillation tower 300 is a separating tank (350) is supplied can be re-used after predetermined processing. Here, as a device for separation by a separation tank 350 is gravity or centrifugal force, a liquid that is immiscible with each other, relatively (e. G., Organic phase) light liquid is a set of phase separation the upper, relatively heavy liquid (e.g., " g., water) may be returned to the set of phase separating the lower.

As an example and an upper liquid outlet 304 of the azeotropic distillation tower 300. Some of the above-mentioned (meth) acrylic acid extraction column 200, the balance weight 201 may be discharged from the separation of the organic phase and the aqueous phase comprising water, comprising a solvent, in the separating tank (350).

here. The separated organic phase 351 is fed to the upper end of the azeotropic distillation column 300 may be used as the azeotropic solvent (301), at least a portion of the organic phase (351) is supplied to the (meth) acrylic acid extraction column 200, the extraction solvent It may be used in 302. And, at least a portion of the award 352 is separated from the phase separation vessel is fed into a (meth) acrylic acid absorption tower 100 can be used again as the absorption solvent 352, some of which may be treated by the waste water (waste) . In addition, the award there may be some acid is included, the concentration of acetic acid contained in the water phase can vary, depending upon the type of the azeotropic solvent and the reflux ratio.

And, according to one embodiment of the invention, the azeotropic distillation process, to can be preferably conducted under the conditions that satisfy Equation 4 and 5.

[Equation 4]

Y = Y1 + Y2

[Equation 5]

Υ2>Υ1

In Equation 4 and 5,

Ύ, the D) the total amount of the azeotropic solvent used in the step , and,

Y1 is, the amount of extraction solvent used in the above B-1) stages,

Υ2 is the amount of the azeotropic solvent, the D) that is added separately from the upper azeotropic distillation tower 300 in the step.

As described above, the extraction, for use in the present invention the solvent (Y1), and i azeotropic " azeotropic solvent (Υ2) is added separately in the" type process is preferably in view of the production efficiency, according to the continuous process, using the same it is reused together, with the extraction solvent (Y1), an azeotropic distillation an azeotropic solvent (Υ2) is added separately in the process, through the processing in the above-described phase separation vessel 350, and separated into an organic phase, extraction and azeotropic distillation, etc. since the same as the total amount of the azeotropic solvent to be used in the azeotropic distillation step of the amount D) a hydrophobic organic solvent which is circulated throughout the process (Υ), which, the extraction solvent (Y1) used for the B-1) stage extraction process of the and D) and is fixed to the sum of the azeotropic solvent (Υ2) is added separately in the azeotropic distillation process values.

The amount of this time, the separated through the process in the separation above the tank 350. The organic phase (351, Υ) wherein the azeotropic distillation step as an azeotropic solvent (301, Υ2) are added separately, it is circulated to the extraction process, (meth) is preferably greater than the amount of the extraction solvent (302, Y1) to be introduced into the azeotropic distillation tower 300, with the acrylic acid extract (203).

Azeotropic distillation column azeotropic be separately introduced into the top of 300, solvent (301, Υ2) a (meth) acrylic acid extract 203 the extraction solvent (3 flowing into the azeotropic distillation tower 300, with the amount of " the amount of 02, Y1) If that is more reduced so that the amount of (meth) which is included in the top discharge liquid 304 discharged from the upper loss in the azeotropic distillation tower 300, acrylic acid becomes large, the efficiency of the azeotropic distillation may cause a problem of significantly decreased.

On the other hand, the (meth> acid aqueous solution are (meth) acrylic acid absorption tower 100,

(Meth) acrylic acid while passing through the extraction column 200, and the azeotropic distillation tower 300 or the like, at least a portion of the (meth) acrylic acid contained in the aqueous solution to form a dimer or oligomer. To this (meth) minimizing polymerization of acrylic acid, the azeotropic distillation tower 300, there may be added a conventional polymerization inhibitor.

Then, the lower discharge liquid 303 of the azeotropic distillation tower 300, a (meth) acrylate in addition to (meth) itol contains such high boiling point by-product of the polymerization inhibitor deungah and acrylic acid polymers. Thus, if necessary, to lower the discharge amount of the azeotropic distillation tower 300 is a high boiling by point by-product supplied to the separation column 400, wherein - the lower discharge liquid 303 to '' in the step of separating the high boiling point by-product comprising adding It can be carried out.

Then, the number of times over the course crude (meth) acrylic acid (CAA) can be obtained by (meth) acrylic acid (HPAA) of higher purity through an additional crystallization step. At this time, the high boiling point by-product separation step and washing determined times . Process and the like can be carried out under conventional conditions, process conditions, etc. are not specifically limited.

In such a (meth) acrylic acid recovery method, the steps described above can be carried out in the organic and continuous. And, in addition to the above-described process steps that may be performed before or after or at the same time as each of the conventional steps may be operated it is further included.

This process, (meth) acrylic acid can be carried out through the absorption tower 100, a (meth) acrylic acid extraction column 200, and the azeotropic distillation column consisting of 300 unit. The apparatus, More specifically, the (meth) acrylic acid absorption tower 100; Contacting the (meth) acrylic acid aqueous solution 103 of the first concentration discharged from the side of the (meth) acrylic acid absorption tower 100 and the extraction solvent comprising a hydrophobic organic solvent, (meth) for extracting acrylic acid, (meth ) acid extraction column 200; Extracted

(Meth) acrylic acid extract, 203 ' and a (meth) to obtain a (meth) acrylic acid by distillation of (meth) acrylic acid aqueous solution 102 of the second concentration discharged from the bottom of the (meth) acrylic acid absorption tower 100 It may be a device including acrylic acid azeotropic distillation tower 300.

(Meth) acrylic acid absorption tower 100, the stepped type column (packed column type)

(Meth) acrylic acid absorption tower. Multistage tray type (multistage tray type) may be, the above packed column type of (meth) acrylic acid absorption tower lashing inside ¾ Crashing ring), polling (pall ring), saddle (saddle), gauze (gauze), structured packing may be a filler of the like is applied (structured packing).

In particular, in the one embodiment of (meth) acrylic acid (meth) acrylic acid absorption tower 100, a first density emission unit, the (meth) downward from the top and the acrylic acid absorption tower 100, or about 40 to about 99% which may be located at any one point, more preferably, any of the points corresponding to about 60 to about 80% downward from the top of the (meth) acrylic acid absorption tower 100. In the above range, the case having first concentration emission unit, the (meth) and to maximize the absorption efficiency of acrylic acid absorption tower 100 and also possible to minimize the processing load in the subsequent extraction step and the azeotropic distillation process, i do.

In the one embodiment the apparatus, essentially of (meth) acrylic acid absorption tower 100 may be connected to the first concentration of (meth) acrylic acid aqueous solution (103) through a transfer line (meth) acrylic acid extraction column 200 of the side . Then, the (meth) acrylic acid extraction column 200 of (meth) acrylic acid extract 203 may be associated with an azeotropic distillation tower 300 through a feed line ^, and the (meth) acrylic acid hop water tower 100, the lowermost first concentration (meth) acrylic acid aqueous solution and directly coupled to 102 the azeotropic distillation tower 300 through a feed line.

And the eu (meth) acrylic acid extraction column 200 includes a liquid - can be used without a conventional (meth) acrylic acid extraction column 200 of the liquid contact method limited. Non-limiting examples, the (meth) acrylic acid extraction column 200 of the reciprocating plate column type Karr (reciprocating plate Karr column type), rotary-disk type column (rotary-disk contactor). Scheibel column, Kuhni column. Spray (meth) acrylic acid extraction column (spray extraction tower), filled (meth) acrylate,

State may be a jultap (extract ion packed tower), Phelps packed column (pul sed packed column).

Then, the solvent recovery column and the azeotropic distillation tower 300 is a pack containing the aforementioned fillers inside the column or multi-stage column, preferably a sieve tray column (si eve tray column), a dual flow tray column (dual f low tray column) this may be equipped.

In addition, the (meth) acrylic acid recovering device according to the invention, may be one having a conventional configuration in the art.

Hereinafter, a concrete embodiment of the invention, rather than to the above-described operations and effects of the invention. However, this embodiment is merely given as an example of the invention: As a result is not defined the scope of the invention.

(Meth) acrylic acid absorption step

Absorption step of Example 1

The top the absorption section. Is provided, and the lower portion having a nyaenggak interval. E a: the nyaenggak to the lower condensate re-introduced into (meth) acrylic acid absorption tower 100, the heat exchanger is contained, a (meth) acrylic acid absorption tower 100, were prepared.

Absorption interval, and an internal diameter of 70.6cm, a down keomeo sieve trays (sieve tray) containing the (down-comer) to a 7cm interval, was composed of 39.

Nyaenggak section which is located directly below the absorption zone is an internal diameter of 100cm, aperture ratio is 17%, subject to the dual flow tray (dual f low tray) is Hole ID 3 画, with 10cm intervals, hayeotda composed of four steps.

(Meth) liquid ungchuk the lower acrylic acid absorption tower 100, to nyaenggak was passed through an indirect heat exchange, (meth) top of nyaenggak section of the acrylic acid absorption tower 100 in the way that reclosing the (top of the dual flow trays) by,

(Meth) acrylic acid absorption tower 100 is maintained at a constant temperature of the top.

Heunhap gas (1) containing acrylic acid, 800 ° 1001 / N min, heated to a high temperature of the C 2 and, acrylic acid, acetic acid and water are respectively 60.9% by weight, 1.85% by weight eu

Contacting an aqueous solution of a, 46.2g / min contained by 37.25 wt%, 165 ° was prepared by dilution of the gas C, it was added from the bottom of the (meth) acrylic acid absorption tower 100.

(Meth) acrylic acid, the top of the absorption tower 100, the acrylic acid was added and the, number of absorption acid is 1.66, respectively, 8.2% by weight, 18.23g / min.

(Meth) by means of a pump in, 27th sieve tray from the top of the acrylic acid absorption tower 100 (hereinafter, may discharge end), and discharging the first concentration aqueous solution of acrylic acid 8.79g / min (103). A first concentration in the aqueous acrylic acid solution, the concentration of acrylic acid and acetic acid are, respectively, was 21.66 weight 3.84% by weight.

(Meth) acrylic acid absorption tower 100, the top temperature of 64 ° remains constant as C, and the (meth) acrylic acid absorption tower 100 is kept constant the level of the lower liquid, the (meth) acrylic acid absorption tower 100 second density through the lower , discharge the acrylic acid aqueous solution was de-102.

For about 10 hours (meth) acrylic acid absorption column after the operation 100 '; (Meth) acrylic acid absorption tower 100, the discharge flow rate of the bottom liquid, i.e. the flow rate of the second concentration of aqueous acrylic acid solution was was 33.49g / min, the concentration of acrylic acid and acetic acid were respectively 77 and 65% by weight, 2.38% by weight.

(Meth) arc ¾ acid absorption tower 100 is discharged to the upper " biung layering ■ gas 101 was discharged to 147.22g / min, the exhaust gas increases, the concentration of acrylic acid is 0.41% by weight, H 2 0 / N 2 the ratio is 16.4: the second temperature of the acrylic acid aqueous solution in which the concentration was 100, the discharge is 76.3 ° the uppermost and lowermost pressure of the C, (meth) acrylic acid absorption tower 100, was respectively 117mbar, 162mbar.

A first concentration of acid : was a ratio of 5: The amount contained in the water volume and the second concentration aqueous solution of acrylic acid contained in the aqueous solution of water and 5. (Hereinafter, the water ratio)

Absorption process performed Examples 2 to 9

Uihadoe in the same manner as Example 1, to varying the number of stages and the flow rate for discharging the first concentration aqueous solution of acrylic acid, (meth) acrylic acid absorption step was performed.

Absorption step in Comparative Example 1

Without side discharge, a lower, second concentration of acrylic acid discharged only a single stream.

The absorption zone is provided at the top, and a bottom provided with a nyaenggak interval, In addition, the nyaenggak the lower Hung chukaek to re-supply the (meth) acrylic acid absorption tower 100, the heat exchanger is contained, a (meth) acrylic acid absorption tower ( 100) were prepared.

Absorption interval, and an internal diameter of 70.6cm, a keomeo down (down-comer) the sieve tray (s ieve tray) by including a gap in 7cni, was composed of 39.

Nyaenggak section which is located directly below the absorption zone is an internal diameter of 100cm, aperture ratio is 17%, subject to the dual flow tray (dual f low tray) is Hole ID 3 隱, with 10cm intervals, hayeotda composed of four steps.

(Meth) liquid ungchuk the lower acrylic acid absorption tower 100, to nyaenggak was passed through an indirect heat exchange, (meth) top of nyaenggak section of the acrylic acid absorption tower 100 in the way that reclosing the (top of the dual flow trays) by.

(Meth) acrylic acid absorption tower 100 is maintained at a constant temperature of the top.

Heunhap gas (1) containing acrylic acid, 800 ° 1001 / N min, heated to a high temperature of the C 2 and, acrylic acid, acetic acid, 60.9% by weight of water, respectively, 1.85% by weight,

Contacting an aqueous solution of 46.2g / niin include at 37.25% by weight, 165 ° was prepared by dilution of the gas C, it was added an O from the lower portion of the (meth) acrylic acid absorption tower 100.

The top of the (meth) acrylic acid absorption tower 100 is provided, of acrylic acid and acetic acid, respectively

1.73, 8. a phosphorus, water absorption 13% by weight was added to 18.26g / min.

(Meth) acrylic acid of the top absorber 100. The silver is 64 ° remains constant as C, and the (meth) acrylic acid absorption tower 100 is kept constant the level of the lower liquid,

(Meth) acrylic acid aqueous solution of concentration 2 to the discharge was through the acrylic acid, the absorption tower 100, a lower.

For about 10 hours after the operation the (meth) acrylic acid absorption tower 100, a (meth) acrylic acid absorption tower 100, was the flow rate of the discharge flow volume of the lower liquid, that is, the second concentration aqueous solution of acrylic acid was 42.05g / min, acrylic acid and concentration of the acetic acid, each was 66.68% by weight, 2.68% by weight.

(Meth) acrylic acid absorption tower 100 of the biung condensable gas (101) discharged to the upper part, has been discharged to 147.41g / min, the exhaust gas, the concentration of acrylic acid, 0.40 wt%, ¾0 / N 2 ratio is, 16.4: second concentration acrylic acid aqueous solution was 100, the discharge of the

Temperature is 74.1 ° the uppermost and lowermost pressure of the C, (meth) acrylic acid absorption tower (10Q) was respectively 112mbar, 160mbar.

Absorption process embodiment and to the process conditions of the comparative example were summarized in Table 1, the (meth) acrylic acid absorption tower 100, a first concentration of aqueous acrylic acid solution 103 indicators discharged to the side shown in Table 2, the (meth) acrylic acid clean the second concentration of aqueous acrylic acid solution 102, the indicators in Table 3, the (meth) acrylic acid absorption tower 100, the non-condensable gas (101) discharged to the upper indicators discharged to the lower absorber 100 in table 4 It was.

[Table II

The silver *: discharged to a lower second concentration aqueous acrylic acid solution temperature

[Table 21

Example 3 7.9 13.09 4.38 Example 4 8.4 4.01 17.75 Example 5 13.0 47.62 3.18 5.26 19.15 Example 6 3.92 Example 7 6.89 20.07 3.84 Example 8 10.74 3.82 23.25 Example 9 12.59 26.42 3.87 Comparative Example 1 eu -

[Table 3]

[Table 4]

Example 4 147.60 0.43 16.6

Example 5 147.28 0.41 16.6

Example 6 147.30 0.39 16.4

Example 7 147.23 0.40 16.4

Example 8 147.15 0.40 16.4

Example 9 0.41 16.5 147.29

Comparative Example 1 147.41 0.40 16.4

Referring to Table 1 to 4, as in the embodiment of the invention, (Bernadette) when an additional discharge the relative concentration of the acrylic acid lower stream through the side portion of the acrylic acid absorption tower 100, the acrylic acid which is discharged to the lower the concentration without lowering the separation efficiency, yet be increased at least about 10 percent, it can be seen that to reduce the amount of acrylic acid loss is included in the absorber overhead exhaust biung condensable gas. Also, as the discharge of the first concentration of aqueous acrylic acid solution from the stage relatively in the lower part, it can be seen that the increase in the absorption efficiency. However, first, by increasing the concentration of aqueous acrylic acid solution discharged from the bottom, the first concentration; acid aqueous solution , within ah. There is higher concentration of Ξί rilsan, in this case. When viewed from the bar, this point of view, which can result in large the process load in the subsequent (meth) acrylic acid extraction step and the azeotropic distillation process issues, to the (meth) acrylic acid solution discharged from the first concentration of the (meth) acrylic acid absorption tower when discharged from the end corresponding to the height of about 40 to about 99% downward from the top, four to more preferably a single corresponding to a height of about 60 to about 80% downward from the top of the (meth) acrylic acid absorption tower when the discharge, it was confirmed that it can greatly increase the efficiency of the overall process.

(Meth) acrylic acid extraction step

Extraction Process Comparative Example 1

The inner diameter is 22 隱, using a reciprocating plate column (Karr type rec iprocat ing plate column) of the Karr type of shot 56, a (meth) acrylic acid extraction column was constructed (200).

Of 4 to 15 parts by weight of (meth) were introduced into a 35.9g / min in the first stage the top of the acrylic acid extraction column 200, the extraction solvent is an azeotropic distillation tower (300) to the first concentration acrylic acid solution (acrylic acid: 21.06 parts by weight of acetic acid. the resulting organic phase was with 351 at the upper part of the discharge liquid using a reflux stream comprising toluene, the extraction solvent is an acid of 0.28 wt%, 0.5 wt% acetic acid, and the remaining amount included the toluene.

Extraction solvent, (meth) was introduced to 59.48g / min through the bottom of the extraction column 56 of the acrylic acid (200).

In the normal state, the (meth) acrylic acid extraction column top (200), 66.67g / min at a flow rate, the extract was discharged eu extract the acrylic acid of 10.1% by weight, 0.66% by weight of water increased 0.75 acetate, and the remaining It contains the influenza.

(: Methoxy ^) to the lower portion of the acid extraction column 200, a, the weight balances containing 3.49% by weight of acrylic acid, acetic acid 4.36 weight% eu remaining amount of water was discharged.

(Meth) acrylic acid extraction column 200, during operation, the water removal rate of the first concentration acrylic acid aqueous solution was 98.4%, acid extraction was.

(Meth) acrylic acid. Extraction Column (200) during operation, (meth) acrylic acid extraction column 200, the extraction solvent / water ratio injected into the (a) was, 2.18.

To the operating conditions and results are summarized in Table 1 below.

Extraction Process Examples 1-5

(Meth) and has, was carried out in the same manner as in the Comparative Example 2, except that a different acid extraction column 200, during operation, the (meth) ratio (a) of the extraction solvent / block put into the acid extraction column 200.

To the operating conditions and results are summarized in Table 5.

[Table 5]

Referring to Table 5, the extraction solvent / water increased when the forward ratio at about 2.5 or more conditions, the water removal rate and acrylic acid extraction greatly improves the name to be i to check exactly, specifically the acrylic acid concentration in the weight balance that it can significantly reduce it could definitely see. Dameon-extracted solvent / if to increase the proportion of water too, this becomes relatively large as (Y1) amount of the extraction solvent to be added in the extraction process, and thus, in the azeotropic distillation process, leading later, amount of the azeotropic solvent to be refluxed (Y2 ) it can be held down. Therefore, when considering the purification efficiency in the efficiency of the extraction step and the azeotropic distillation process, wherein, ? It can be seen that it is preferable to extract the solvent / water ratio to maintain at about 2.5 to about 4.0.

Azeotropic Distillation

Azeotropic distillation process of Example 1

By azeotropic distillation tower 300, was used as the si eve tray (including down keomeo) column of internal diameter of 300 隱 the gun 39, the operating pressure was maintained at llOtorr.

The extraction procedure in Example 2, i.e. (meth) the extraction solvent / water ratio (a) charged into the acid extraction column 200, based on the extraction tower results of when to 3.30, (meth) acrylic acid extraction column 200, a of the discharge to the upper part of (meth) acrylic acid extract, 203, discharged to the lower portion of the (meth) acrylic acid absorption tower 100, a second concentration of (meth) acrylic acid aqueous solution from the top of the azeotropic distillation tower 300, the the location of 20, were each introduced at a rate of 20.9g / min, 30.4g / min. .

Azeotropic solvent (Y2) is a part of the reflux stream comprising toluene and the resulting organic phase with 351 in the upper liquid discharge of the azeotropic distillation tower 300, in the first stage the top of the azeotropic distillation tower 300, 19.9g / It was added to min (the influenza).

Through a bottom reboil of the azeotropic distillation tower 300, by supplying heat, the temperature of claim 20 from above about 68.9 ° , the temperature of C, the 15 approximately 46 ° and adjusted to maintain enough C.

After performing a stable operation for about 6 hours, to the top, an azeotropic distillation tower 300 in the normal state. Was of 46.08g / min top discharge liquid 304 is discharged, as is the lower, the lower outlet 25. The liquid 303 was obtained containing acrylic acid at a flow rate of 12g / min.

The temperature of the azeotropic distillation tower 300, the top in the steady state was about 40.2 ° C, the temperature of the bottom was kept at about 94. c.

To the operating conditions and the results Results of the azeotropic distillation column are summarized in Table 2 below.

Azeotropic distillation process in Comparative Example 1

By azeotropic distillation tower 300, was used as the sieve tray (including down keomeo) column of internal diameter of 300 圍 the gun 39, the operating pressure was maintained at llOtorr.

The absorption step in Comparative Example 1, that is, to the lower portion on the basis of a result of discharging only a single stream, the second concentration of (meth) acrylic acid solution discharged to the lower portion of the (meth) arc ralsan absorber 100, the azeotropic distillation tower ( in from the upper part of 300), the location of the 20, were each introduced into a 20.4g / min flow rate.

Azeotropic solvent (Y2) is a part of the reflux stream comprising toluene and the resulting organic phase with 351 in the upper liquid discharge of the azeotropic distillation tower 300, at the top to a first end of the azeotropic distillation tower 300 39.66g / It was added to min (the influenza).

Through a bottom reboil of the azeotropic distillation tower 300, by supplying heat, the temperature is about 20 69 from the upper ° the temperature of the C, claim 15 of about 45 ° was adjusted to maintain enough C.

After performing a stable operation for about 6 hours, in an azeotropic distillation column top 300 is in a normal state, of 46.78g / min top discharge liquid 304 has been discharged, a lower part, the acrylic acid of 13.28g / niin flow the lower liquid outlet 303 comprises obtained. '

The temperature of the azeotropic distillation tower 300, the top in the steady state was about 39.6 ° C, the temperature of the bottom was kept at about 94 ° C.

To the operating conditions and the results Results of the azeotropic distillation column are summarized in Table 6.

[Table 6]

102: of the second concentration discharged from the bottom of the acrylic acid absorption tower 100, a (meth) acrylic acid aqueous solution

203: acrylic acid (meth) acrylic acid extract 203

301: an azeotropic solvent supplied to the upper end of the azeotropic distillation tower 300

304: upper portion is discharged to the azeotropic tower overhead emitted liquid

303: containing the acrylic acid, the azeotropic distillation column bottom liquid outlet

Referring to Table 6, the weight balance which is the concentration, discharged to the lower by maintaining the ratio of water to the extraction solvent over a certain time to extract from the acid extraction column 200, the acrylic acid (meth) which includes the lower stream in, it was confirmed that to reduce the concentration of acid above about 30%. In the azeotropic distillation column of the conventional process were to remove the water by azeotropic distillation with the solvent, the weight balance is discharged from the extraction tower in the embodiment of the present invention separate by removing the water without the use of energy, water was removed from the azeotropic distillation according to Kim soham, and reduced processing load of the azeotropic distillation, it was found that the total energy consumption greatly reduced.

[Description of Symbols]

1: gas heunhap 100: (meth) acrylic acid absorption tower

101: (meth) acrylic acid ah deaerated, non-condensable gases

102: a (meth) acrylic acid aqueous solution of the second concentration

103: The I degrees (meth) acrylic acid aqueous solution

150: ethyl absorber 151: ethyl absorbing solvent

152: 200 acetic acid aqueous solution containing: (meth) acrylic acid extraction column

201: (meth) acrylic acid absorbing solvent 203: (meth) acrylic acid extract

300: azeotropic distillation

301: azeotropic solvent to be separately fed to the azeotropic tower overhead

302: The extraction solvent 303: azeotropic distillation column bottom liquid outlet

304: azeotropic distillation column top liquid outlet 350: a separation vessel

351: phase separation tank the separated organic phase in the

352: phase-separating tank in a " separate awards, (meth) acrylic acid absorbing solvent

400: high boiling point byproducts separation column

WE CLAIM

[Claim 1]

A) (meth) acrylic acid to create a step, by contacting the mixed gas containing the organic by-products and water vapor (meth) acrylic acid and water from the absorber (meth) acrylic acid aqueous solution;

B) (meth) acrylic acid comprising: at the side of the absorption tower, discharge a (meth) acrylic acid aqueous solution of the first concentration;

C) a (meth) acrylic acid comprising: at the bottom of the absorption tower, discharge a (meth) acrylic acid aqueous solution of a second concentration;

B-1) a (meth) acrylic acid aqueous solution of the first concentration to the discharge side

(Meth) acrylic acid in the extraction column, is brought into contact with an extraction solvent comprising a hydrophobic organic solvent, (meth) extracting acrylic acid; And .

'D) a (meth) acrylic acid aqueous solution of the second concentration discharged from the (meth) acrylic acid extract, and commerce C) phase extracted from the B-1) step, by distillation with an azeotropic distillation process, a (meth) to give the acid comprising, and

Wherein the first concentration, than the second concentration, and (meth) was the concentration of acrylic acid it is low, to the (meth) satisfying the equation (1) recovery of acrylic acid by:

Equation 1

Yl=a XXl

In the equation (1),

Y1 is, the amount of extraction solvent used in the above B-1) stages,

A is, the extraction solvent ratio, above 2.5,

XI is, the first concentration (meth) the amount of water contained in the acid aqueous solution.

[Claim 2]

According to claim 1,

(Meth) acrylic acid solution discharged from the first concentration, wherein the (meth) (meth) a method for recovering acrylic acid is discharged at one point corresponding to a height of 40 to 99% downward from the top of the acrylic acid absorption tower.

[Claim 3]

According to claim 1,

The steps for creating the above-mentioned (meth) acrylic acid aqueous solution, 1 to 1.5 ar pressure and 50 to 100 ° , the (meth) acrylic acid recovery method is conducted at a temperature condition of C.

[Claim 4]

Crab according to claim 1, wherein

(Meth) acrylic acid aqueous solution of the first concentration of (meth) (meth) acrylic acid containing less than 40% by weight of a method for recovering acrylic acid.

[5.]

According to claim 1,

(Meth) acrylic acid aqueous solution of the second concentration of (meth) (meth) acrylate containing at least 60% by weight of a method for recovering acrylic acid.

[6.]

According to claim 1,

(Meth) acrylic acid aqueous solution of the first concentration is discharged to the side part is, in the preparation of (meth) acrylic acid aqueous solution of the second concentration discharged from the bottom, the (meth) acrylic acid is discharged at a rate of 10% to 50% by weight returns.

[Claim 7]

The method of claim 1, wherein the (meth) satisfying the equation (2) the recovery of acrylic acid by:

Equation (2)

0.01 < X1/(X1+X2) < 0.7

In Equation 2, ' and XI is, to the amount of water of (meth) acrylic acid aqueous solution of concentration 1,

X2 is a quantity of water in the second (meth) acrylic acid aqueous solution of concentration.

[8.]

According to claim 1, satisfying the equation (3). (Meth) acrylic acid recovered by:

[Equation 3]

Y-b X2

The equation . In the third,

Y is a positive, the azeotropic solvent used in D) steps,

b, and the ball BB,

X2 is, the second concentration (meth) the amount of water contained in the acid aqueous solution.

[9.]

According to claim 1,

The B-1) used in the solvent extraction stage and wherein D) the azeotropic solvent used in the step are the same with each other, to Equation (4) and (meth satisfying 5) recovery of acrylic acid by:

[Equation 4]

Y=YJ. Y2

[Equation 5]

Y2>Y1

In Equation 4 and 5,

Υ is the total amount of the azeotropic solvent to be used in the D) step,

Y1 is, the amount of extraction solvent used in the above B-1) stages,

Υ2 is, the amount of the azeotropic solvent to be added in the D) step.