KR101857330B1 - Separating and recovering method of unreacted alcohol - Google Patents

Separating and recovering method of unreacted alcohol Download PDF

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KR101857330B1
KR101857330B1 KR1020150184206A KR20150184206A KR101857330B1 KR 101857330 B1 KR101857330 B1 KR 101857330B1 KR 1020150184206 A KR1020150184206 A KR 1020150184206A KR 20150184206 A KR20150184206 A KR 20150184206A KR 101857330 B1 KR101857330 B1 KR 101857330B1
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unreacted alcohol
unreacted
alcohol
reflux
vacuum
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KR20170074660A (en
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이시내
이하나
이성규
신준호
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주식회사 엘지화학
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
    • C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
    • C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
    • C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
    • C07C29/78—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by condensation or crystallisation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C31/00—Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
    • C07C31/02—Monohydroxylic acyclic alcohols
    • C07C31/12—Monohydroxylic acyclic alcohols containing four carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C31/00—Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
    • C07C31/02—Monohydroxylic acyclic alcohols
    • C07C31/125—Monohydroxylic acyclic alcohols containing five to twenty-two carbon atoms

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Abstract

Disclosed is a method for separating and recovering unreacted alcohol capable of separating and recovering unreacted alcohol in one process. The method for separating and recovering unreacted alcohol is a method for separating unreacted alcohol existing in the reactor after the reaction in various production processes using alcohol as a reactant. The reflux ratio, the reflux rate, And regulating the amount of heat energy supplied to separate and recover unreacted alcohol in one process.

Description

[0001] SEPARATING AND RECOVERING METHOD OF UNREACTED ALCOHOL [0002]

The present invention relates to a method for separating and recovering unreacted alcohol, and more particularly, to a method for separating and recovering unreacted alcohol capable of separating and recovering unreacted alcohol in a single process.

In the distillation process, the continuous process is recognized as a low labor-intensive process as well as a high energy efficiency as compared with the batch process. However, in the case of the batch process, since the process has flexibility, Type products can be separated from one distillation column, and various kinds of manufacturing processes can be performed in a short time. Therefore, in order to separate unreacted alcohol, it is necessary to use a method of reacting alcohol such as butanol and octanol by a batch process. After such reaction, unreacted alcohol and solvent Etc. are boiled at the same time, and the recovered alcohol mixture is subjected to an additional separation step, whereby the unreacted alcohol can be separated.

Korea Patent Registration No. 10-0797972

Korea Institute of Chemical Engineers, 2001, Vol. 7, No. 1, pp. 601 (Issued on Apr.27 ~ 28, 2001)

As described above, since various kinds of products can be separated from one distillation column and various kinds of manufacturing processes can be performed in a short time, even though the batch process is mostly used when the unreacted alcohol is separated , Since the additional separation step must be separately performed in order to separate unreacted alcohol contained in the recovered alcohol mixture, a large amount of operation cost is required, and there is a high possibility of product loss. The advantage is not maximized.

Accordingly, it is an object of the present invention to provide a method for separating and recovering unreacted alcohol in a single process, and a method for separating and recovering unreacted alcohol capable of re-feeding separated unreacted alcohol as a starting material .

In order to accomplish the above object, the present invention provides a process for separating unreacted alcohol present in a reactor after a reaction in various production processes using an alcohol as a reactant, wherein a reflux ratio, a reflux rate, And separating and recovering unreacted alcohol in one process by regulating the amount of heat energy supplied to the process for separating and recovering unreacted alcohol.

According to the method for separating and recovering unreacted alcohol according to the present invention, it is possible not only to separate and recover unreacted alcohol in one process, but also to recover the separated unreacted alcohol directly as a reaction raw material.

FIG. 1 is a process diagram illustrating a method for separating and recovering unreacted alcohol according to an embodiment of the present invention. Referring to FIG.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The method for separating and recovering unreacted alcohol according to the present invention is a method for separating and recovering unreacted alcohols existing in the reactor after the reaction from the product of the reaction in various production processes using two or more alcohols having different boiling points as reactants , Reflux ratio, reflux rate, degree of vacuum and heat (without discharging the mixture of two or more alcohols contained in the reaction product to the outside to separate the unreacted alcohol from each other) And controlling the energy supply amount to separate and recover unreacted alcohol in one process.

Meanwhile, the method of separating and recovering unreacted alcohol according to the present invention may be carried out by adjusting the operating conditions such as the reflux ratio, the reflux amount, the degree of vacuum, and the amount of heat energy supplied, as described above, And the unreacted alcohol contained in the unreacted alcohol is separately separated and recovered. The process apparatus used in the method for separating and recovering the unreacted alcohol according to the present invention is not so different from the usual process, , The process apparatus used in the separation and recovery method of the unreacted alcohol according to the present invention will be briefly explained.

FIG. 1 is a process diagram illustrating a method for separating and recovering unreacted alcohol according to an embodiment of the present invention. Referring to FIG. Referring to FIG. 1, the unreacted alcohol is separated from the unreacted alcohol by reacting the reactants containing the alcohols in a reactor (or a reactor) in the production process in which two kinds of alcohols having different boiling points are reactants, (Ii) supplying a reaction product containing two unreacted alcohols to the distillation column 200 by supplying vacuum and thermal energy to the reaction product containing the two types of unreacted alcohol, (Iii) conveying the vaporized material separated and discharged to the top (or top) of the distillation tower to a condenser (or a heat exchanger, 300) to condense the liquid into a liquid material, And returning to the distillation column 200 according to the reflux ratio so that low-boiling unreacted alcohol remains in the upper part of the distillation tower and high boiling point unreacted alcohol remains in the lower part. Iv) Recovering the low boiling point unreacted alcohol remaining on the upper portion through a reflux drum, and v) recovering the high boiling point unreacted alcohol remaining in the lower portion of the distillation column after recovery of the low boiling point unreacted alcohol through a reflux drum. Unreacted alcohols are separated from each other. Meanwhile, the apparatus indicated at 400 is a reflux drum (or reflux drum), which stores the condensate and discharges it to the outside or reflux to the distillation tower 200.

The conventional unreacted alcohol separation method separates unreacted alcohols according to the kind by separating all the components except for the reaction products by increasing the degree of vacuum and condensing them after evaporating the unreacted alcohol. That is, in other words, a reactor, a distillation column and a condenser are used, but unlike the present invention, there is a difference in that the product by the last device is an alcohol mixture rather than an unreacted alcohol. Hereinafter, It is possible to separate unreacted alcohols in one process without any additional process, unlike the conventional unreacted alcohol separation process.

The separation and recovery method of the unreacted alcohol according to the present invention is characterized in that when the above processes (reaction, distillation and condensation) are performed, the reflux ratio, the reflux rate, And the amount of heat energy supplied, the unreacted alcohol contained in the reaction product is separated and recovered in the same process. Meanwhile, various production processes using the alcohol as a reactant include a process for producing an intended product by reacting with an alcohol, for example, when the present invention is applied to a process for producing a plasticizer, 100) can be supplied with raw materials necessary for the production of alcohol and a plasticizer.

When the alcohol mixture is fed to the distillation column 200 and the fractional distillation is performed according to the difference in boiling point, the unreacted alcohol having a relatively high boiling point is left as it is and the unreacted alcohol having relatively low boiling point The alcohol is first separated and recovered to the upper portion of the distillation column 200 and then the unreacted alcohol having a relatively high boiling point is recovered to the upper portion of the distillation column 200 to reuse each unreacted alcohol . In other words, when the operating conditions such as the reflux ratio, the reflux amount, the degree of vacuum, and the supply of heat energy are controlled, high purity unreacted alcohol can be selectively separated and recovered in the same process.

Here, when the unreacted alcohol separated from the alcohol mixture is, for example, unreacted butanol and unreacted octanol, the purity of the unreacted butanol is 98.5 wt% or more, preferably 98.9 wt% or more, Is 99.0 wt% or more, and the purity of the unreacted octanol is 97.0 wt% or more, preferably 97.3 wt% or more, more preferably 97.5 wt% or more.

As described above, the reflux ratio among the operating conditions (the reflux ratio, the reflux amount, the degree of vacuum, and the thermal energy supply) for allowing the unreacted alcohol to be separated and recovered in the same process will be described first. The reflux ratio is a ratio of an alcohol mixture which is refluxed to the distillation column 200 and an alcohol mixture which is recovered in the alcohol mixture produced through the distillation column 200 and the condenser 300, 5.0, preferably 1.0 to 4.5, but may be variable depending on the operating time or other operating conditions, and the ratio may be changed during operation to further optimize the separation of unreacted alcohol. However, in changing the ratio, it is preferable to continuously increase the amount of the alcohol mixture which is refluxed to the distillation column 200 with the lapse of time. When the reflux ratio is adjusted as described above, the steam flowing out to the upper portion of the tower is condensed, and then a part of the steam is returned to the upper portion of the column to maintain heat exchange and phase equilibrium with the steam rising to the upper portion of the column. By lowering the high component, the unreacted alcohol can be easily separated.

The reflux rate refers to the flow rate of the alcohol mixture which is refluxed to the distillation column 200 in the alcohol mixture produced through the distillation column 200 and the condenser 300, kg / hr, preferably 300 to 3,700 kg / hr, but it can be varied depending on the operation time or other operating conditions, like the reflux ratio. It is also possible to change the flow rate during operation to further optimize the separation of unreacted alcohol can do. On the other hand, in changing the reflux amount, it is preferable to increase the reflux amount with the elapse of time, and to reduce the reflux amount again when the unreacted alcohol is separated. When the reflux amount is adjusted, the steam flowing out to the upper portion of the column is condensed and then a part of the steam is returned to the upper portion of the column to maintain the heat exchange and the phase equilibrium with the steam rising to the upper portion of the column , The unreacted alcohol can be easily separated by lowering the components having a high boiling point in the outflow to the upper part. The reflux ratio and the reflux amount are classified as a difference in determining the reflux amount as a ratio It is.

The degree of vacuum represents the degree of vacuum of the distillation column 200. In order to separate unreacted alcohol, the distillation column 200 must be in a vacuum state. However, only the distillation column 200 It is impossible to separate unreacted alcohol simply by making it in a vacuum state. The degree of vacuum may be less than or equal to 40 mmHg and less than 760 mmHg, but may vary depending on the operating time or other operating conditions. The degree of vacuum may be varied during operation to further optimize the separation of unreacted alcohol. On the other hand, in changing the degree of vacuum, it is desirable to increase the degree of vacuum stepwise with time (meaning that the degree of vacuum increases, for example, from 760 mmHg to 40 mmHg) The separation time of the reaction alcohol may be further shortened.

Lastly, the supply of the thermal energy is performed when the degree of vacuum of the distillation column 200 is low and it is difficult to separate the unreacted alcohol or when the distillation column 200 can not reach a high vacuum quickly. May be 0.1 to 1 Gcal / hr, preferably 0.3 to 0.7 Gcal / hr, more preferably about 0.5 Gcal / hr, but may vary depending on operation time or other operating conditions Further, when the supply of thermal energy is required, the separation of unreacted alcohol can be further optimized by supplying thermal energy even during operation.

The four operating conditions (reflux ratio, reflux amount, vacuum degree, and heat energy supply) discussed above have the characteristic of facilitating the separation of unreacted alcohol, and the remaining operating conditions except for the vacuum degree are adjusted independently Although the unreacted alcohol may be separated, it is preferred that at least two operating conditions be adjusted together.

Meanwhile, the unreacted alcohol separated as described above can be supplied to the reactor 100 and recycled as a raw material. Particularly, among the unreacted alcohols separated as described above, the alcohol component having a relatively high boiling point (For example, unreacted alcohol is high purity butanol and high purity octanol, boiling point of high purity octanol) is supplied to the reactor 100 through the lower part of the distillation column 200 without any additional treatment, and can be recycled.

If the unreacted alcohol such as high purity butanol and high purity octanol is directly reused in the same process, the unreacted alcohol can be separated and recovered in a separate process and then supplied to the reactor again Not only the cost can be reduced, but also the cost of raw materials can be reduced. Thus, the cost of separating and recovering unreacted alcohol can be drastically reduced.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as set forth in the appended claims. Such changes and modifications are intended to be within the scope of the appended claims.

Example

Isolation of Unreacted Alcohol

[Example 1]

After the plasticizer preparation reaction, a mixture containing 17.8 wt% of octanol, 3.5 wt% of butanol, 78.4 wt% of plasticizer (GL-500, LG Chem) and 0.3 wt% of water remaining in the reactor was fed The distillation and condensation were carried out to separate and recover the unreacted alcohol. At this time, as shown in the following Table 1, starting at the atmospheric pressure (760 mmHg) for the first time, Vacuum was operated at a vacuum of 40 mmHg for 60 minutes, and the reflux ratio in the process was changed from 2 until the operating time of 25 minutes to 4.15 after 60 minutes. By changing the operating conditions, high purity unreacted alcohol was selected Lt; / RTI >

[Example 2]

As shown in Table 1, instead of controlling the reflux ratio in the process, the reflux rate was 1,500 kg / hr until the operating time of 10 minutes, 2,500 kg / hr until 20 minutes, 3,500 kg / hr, 2500 kg / hr until 45 minutes, 1,500 kg / hr until 55 minutes, and 200 kg / hr until 60 minutes, thereby obtaining a high purity unreacted alcohol .

[Example 3]

As shown in Table 1 below, the reflux rate was changed from 2 minutes to 45 minutes, from 2,000 kg / hr to 55 minutes, from 55 minutes to 55 minutes, instead of operating at a vacuum degree of 40 mmHg until 60 minutes. Minute, unreacted alcohol of high purity was selectively obtained in the same manner as in Example 2, except that the amount of the unreacted alcohol was adjusted to 100 kg / hr.

[Example 4]

As shown in the following Table 1, the operation was performed at 130 mmHg instead of operating at a vacuum degree of 40 mmHg from 25 minutes to 60 minutes. The reflux rate was 500 kg / hr for the operation time of 5 minutes, 750 kg / hr / hr, 1,000 kg / hr for 15 minutes, 1,500 kg / hr for 20 minutes, 2,200 kg / hr for 25 minutes, 3,000 kg / hr for 30 minutes, 2,400 kg / hr for 35 minutes, 1,700 kg / Hr of 1,400 kg / hr until 55 minutes, 1,300 kg / hr until 60 minutes, and a heat of 0.5 Gcal / hr from the operation time of 30 minutes to 60 minutes. To obtain a high purity unreacted alcohol selectively.

[Example 5]

As shown in Table 1 below, instead of performing the stepwise vacuum for up to 25 minutes, only up to 5 minutes, and after the stepwise vacuum for 60 minutes, the operation was performed for 40 minutes instead of 40 mmHg of vacuum. The reflux ratio in the process High-purity unreacted alcohol was selectively obtained in the same manner as in Example 1, except that the time until 10 minutes was 2, the time was 3 minutes until 20 minutes, 3.5 after 30 minutes, and 4.15 after the last 40 minutes.

[Example 6]

As shown in the following Table 1, the reflux ratio in the process was 1.25 until the operation time of 10 minutes, 1.5 after 20 minutes, The high-purity unreacted alcohol was selectively obtained in the same manner as in Example 1 except that the heat was supplied at a rate of 0.5 Gcal / hr from the beginning of the operation to the end of the operation from the beginning to the end of 40 minutes .

[Comparative Example 1]

As shown in Table 1 below, only the degree of vacuum in the operating conditions was the same as in Example 1, except for the remaining operating conditions, and the unreacted alcohol was separated from the alcohol mixture.

Figure 112015126020337-pat00001

Evaluation of Purity of Isolated Unreacted Alcohol

[Examples 1 to 6 and Comparative Example 1]

As a result of carrying out in the same manner as Examples 1 to 6 and Comparative Example 1, it was confirmed that the operation conditions such as reflux ratio, reflux rate, vacuum degree and heat energy supply amount were controlled, 6, unreacted alcohols, that is, unreacted butanol and unreacted octanol were separated in high purity through the same in-process distillation column, and in the case of Comparative Example 1 in which the operating conditions in the process were not controlled, the alcohol mixture Only the plasticizer (GL-500) and the solvent were separated, and the purity of the unreacted alcohol separated from the distillation column is shown in Table 2 below. In Table 2, 'purity' indicates the degree of pure alcohol, and the purity of butanol was determined using the relational expression 'butanol / (butanol + octanol) * 100 (%)' Was determined using the relational expression 'octanol / (butanol + octanol) * 100 (%)'.

Figure 112015126020337-pat00002

As shown in Table 2, it can be seen that, in Examples 1 to 6, high-purity butanol was separated from the top of the distillation column and high-purity octanol was separated from the bottom (Btm). Particularly, in the case of the third embodiment in which the degree of vacuum and the reflux rate are simultaneously adjusted, it can be seen that the separation time is shortened (it takes 55 minutes to separate), and as a result, (Comparison of Examples 2 and 3). Further, when the degree of vacuum is low and it is difficult to separate the unreacted alcohol, the unreacted alcohol can be more easily separated through the supply of thermal energy as in the fourth embodiment.

In addition, it is also possible to dramatically shorten the separation time (that is, to shorten the time required for the step-by-step vacuum to reach the high vacuum more quickly) In addition, even when the vacuum can not be quickly reached because a stepwise vacuum is required for a certain period of time, the thermal energy is supplied as in the sixth embodiment, so that the separation time (I.e., completion of unreacted alcohol separation in operation time of 40 minutes). On the other hand, in the case of Comparative Example 1, only the plasticizer (GL-500) and the solvent were separated from the alcohol mixture, and further purification steps were required to separate the unreacted alcohol.

Claims (16)

In the process for producing a plasticizer in which two alcohols having different boiling points are reacted products,
i) supplying a reactant containing two kinds of alcohols having different boiling points to a reactor to react;
ii) supplying vacuum and thermal energy to a reaction mixture containing two kinds of unreacted alcohol, a plasticizer as a product, and water as a by-product to transfer the mixture to a distillation column and fractional distillation;
iii) The vaporized material separated and discharged by the column top of the distillation tower is transferred to a condenser and is condensed with a liquid material. The condensate is returned to the distillation tower in accordance with the reflux amount and the reflux ratio in the reflux drum, Allowing the high boiling point unreacted alcohol to remain;
iv) recovering the low boiling point unreacted alcohol remaining on the top of the distillation tower through a reflux drum; And
v) recovering the high boiling point unreacted alcohol remaining in the lower portion of the distillation column after the recovery of the low boiling point unreacted alcohol through the reflux drum,
Wherein the vacuum of step (ii) is at least 40 mmHg and less than 760 mmHg,
In the step (iv), the reflux ratio is controlled in the range of 1.0 to 4.5, the reflux amount is controlled in the range of 100 to 4,000 kg / hr,
Wherein the two unreacted alcohols are unreacted butanol and unreacted octanol. delete The method of claim 1, wherein the separated unreacted alcohol is fed to the reactor and reused as a raw material. delete delete delete delete delete delete delete The method of claim 1, wherein the distillation column is quickly brought to a high vacuum to shorten the separation time of the unreacted alcohol. The method according to claim 1, wherein the thermal energy is supplied to the distillation column when the degree of vacuum of the distillation column is low and it is difficult to separate the unreacted alcohol or the distillation column can not reach the high vacuum quickly. Separation and recovery method. The method of claim 1, wherein the amount of thermal energy is 0.1 to 1 Gcal / hr. delete The method of claim 1, Wherein the purity of the unreacted butanol is 98.5 wt% or more. The method for separating and recovering unreacted alcohol according to claim 1, wherein the purity of the unreacted octanol is 97.0 wt% or more.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003126602A (en) * 2001-10-19 2003-05-07 Fujitekkusu:Kk Vacuum distillation and regeneration apparatus
US7531688B2 (en) 2007-06-12 2009-05-12 Orbitek, Inc. Method for recovering unreacted alcohol from biodiesel product streams by flash purification

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003126602A (en) * 2001-10-19 2003-05-07 Fujitekkusu:Kk Vacuum distillation and regeneration apparatus
US7531688B2 (en) 2007-06-12 2009-05-12 Orbitek, Inc. Method for recovering unreacted alcohol from biodiesel product streams by flash purification

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