KR100676996B1 - Polymerization inhibitor for 1,3-butadiene and a method of inhibiting polymerization of 1,3-butadiene by imputing thereof - Google Patents

Abstract

The present invention relates to a polymerization inhibitor of 1,3-butadiene and to 1,3-butadiene, comprising 4 tert-butyl catechol (TBC), diethyl hydroxylamine (DEHA) and an organic solvent. It relates to a polymerization prevention method.

The high-purity 1,3-butadiene product can be extracted and distilled by inhibiting the polymerization of 1,3-butadiene in a wide temperature range of gas and liquid state by the polymerization inhibitor having excellent polymerization inhibition to antifouling effect according to the present invention. It is possible to prevent emergency shutdown of the 1,3-butadiene manufacturing plant which may be caused by fouling, and to perform a safe operation for a long time.

Polymerization inhibitors, 1,3-butadiene, diethyl hydroxylamine, isobutyl alcohol, isopropyl alcohol.

Description

Polymerization inhibitor for 1,3-butadiene and a method of inhibiting polymerization of 1,3-butadiene by imputing             

1 is an extractive distillation process diagram for the production of 1,3-butadiene including a process in which the polymerization inhibitor of the present invention is injected.

※ Explanation of Codes on Major Parts of Drawings

1: extractive distillation column

1-a: First Chimney Tray

1-b: Second Chimney Tray

2: In a mixed C ₄ fraction processing (Mixed C ₄ injection point)

3: Dimethylformamide injection point

4: Polymerization inhibitor storage tank

5: Polymerization inhibitor injection pump

6: Condensor

7: Reflux drum

8: Reflux pump strainer

9: Reflux pump

10: column bottom strainer

11: First Reboiler

12: Second Reboiler

1,3-Butadiene distillation unit

B: 1,3-butadiene recovery unit

The present invention relates to a polymerization inhibitor of 1,3-butadiene and a method for preventing polymerization of 1,3-butadiene, which is added thereto. Specifically, the present invention provides a novel method for blocking and preventing the formation of fouling during the production of 1,3-butadiene. It relates to a polymerization inhibitor and a method for preventing polymerization of 1,3-butadiene by putting it in an extractive distillation column.

In the mixed C ₄ oil (Mixed C ₄ ), not only 1,3-butadiene manufacturing plant, which is a raw material for rubber and synthetic resin, but also styrene monomer and isoprene manufacturing plant Because it is an unsaturated hydrocarbon, it can be easily polymerized, causing serious problems such as organic fouling problems in the process even during normal operation. For example, fouling produced in an extractive distillation column may clog the trays in the extractive distillation column, reducing column efficiency, or closing the flow path of the upper condenser to reduce heat transfer efficiency or cause rupture of the apparatus.

Looking at the generation mechanism of the fouling, organic fouling is generally produced by a free radical reaction. Free radicals, that is, atoms or groups of atoms that lack one electron, have a property to make up a stable electron pair by supplementing the lacking electrons, so the reactivity of the free radical reaction is very high. Free radicals are produced by reaction with heat, peroxides or oxygen or catalysis of metals. The free radicals thus formed react quickly with unsaturated hydrocarbons to form resins or rubbery polymers. The free radicals are either hot or have a longer residence time, leading to continued reactions and larger molecular weights. This free radical polymerization terminates the polymerization reaction when two radicals collide or encounter a compound that is highly reactive with free radicals, forming a very stable compound with no activity, causing fouling in the process.

The fouling in the extractive distillation step of the 1,3-butadiene manufacturing plant is an organic fouling in which a popcorn polymer is produced mainly by free radicals.

In other words, the polymer production reaction in the production of 1,3-butadiene is initiated as a peroxide and iron oxide radical as a free radical reaction, and is promoted by oxygen, iron oxide, etc. present in the production process to produce a popcorn type polymer.

In order to solve this problem of organic fouling, residual oxygen and metal components are removed through chemical treatment during regular maintenance of the equipment. In normal operation, 4-tertiary-butylcatechol (4-tertiary-butylcatechol, hereinafter referred to as 'TBC'), diethyl hydroxylamine (N, N-Diethyl hydroxy amine, hereinafter referred to as 'DEHA'), and Antifouling agents such as stabilized free radicals (hereinafter referred to as 'SFR') are used alone.

However, such a single component of the polymerization inhibitor in the process in the gas phase and liquid environment is insufficient to prevent the formation of the polymer, it is not effective for the removal of the polymer already advanced. In addition, 4-tertiary-butylcatechol (TBC) and diethyl hydroxylamine (DEHA) are produced in an aqueous solution of 85% by weight due to the nature of the product is a side effect that causes fouling due to the introduction of unnecessary moisture in the process Follow.

Specifically, the single component polymerization inhibitor has the following problems.

Most popcorn-type polymers occur in the gaseous state, whereas 4-tertiary-butylcatechol (TBC) has a low vapor pressure, so TBC alone cannot exert its anti-polymerization effect in the gaseous process part. In addition, TBC alone cannot stop the progress of the already produced popcorn-type polymer, and since the solid TBC is used by dissolving in 15% by weight of water, the free radical reaction is promoted by water due to the characteristics of the product to promote and foul the polymer. The disadvantage is that the ring is better produced.

In addition, when diethyl hydroxylamine (DEHA) is used alone, it is possible to remove oxygen in the process portion, so that there is a certain effect in the gaseous process portion, but the effect in the liquid state and the gas-liquid process portion Incomplete

In addition, when stabilized free radicals (SFR) are used alone, since the polarization terminator is a good effect in the liquid state compared to TBC, in the gas state there is no effect of preventing the formation of polymers in the form of popcorn, expensive disadvantages There is also.

Currently, the petrochemical industry promotes a lot of productivity and economics by prolonging the regular maintenance cycle with the development of equipment, operation and maintenance technology.However, the petrochemical industry does not overcome the above-mentioned problems in the prior art for preventing organic fouling. Stable operation up to cycle cannot be expected.

Furthermore, an unexpected plant stop due to a large amount of organic fouling may cause a lot of cost and even a risk of explosion of the equipment. Since the shutdown of the 1,3-butadiene manufacturing plant has a great effect on the operation rate of the upper and lower factories in the petrochemical industry, an effective polymerization inhibitor is urgently needed to secure stable operation of the 1,3-butadiene manufacturing plant. Required.

In order to solve the above problems, free radicals, peroxides, water and oxygen are removed in a wide temperature environment of gas and liquid phase during the extraction distillation step of 1,3-butadiene manufacturing process to obtain high purity 1,3-butadiene. It is an object of the present invention to provide a polymerization inhibitor capable of preventing fouling by inhibiting polymerization of 1,3-butadiene and blocking polymer formation, and a method for preventing polymerization of 1,3-butadiene by introducing the same.                         

As a result, the emergency stop of the 1,3-butadiene manufacturing plant that may be caused by fouling is prevented in advance, and a long-term safe operation is possible.

The present invention for solving the above problems is to suppress the popcorn-type polymer, namely, fouling produced during the production of the 1,3-butadiene compound in the extraction distillation step of the high-purity 1,3-butadiene manufacturing process, It provides a polymerization inhibitor used to remove the activity of the popcorn type polymer to obtain a high-purity 1,3-butadiene product.

In addition, the present invention in the extraction distillation step of the manufacturing process of 1,3-butadiene product in the extractive distillation 1,3-butadiene from the C ₄ mixed fraction in the distillation column, 4-tertiary-butylcatechol (4- tert-butylcatechol (hereinafter referred to as 'TBC') and diethyl hydroxyamine (hereinafter referred to as 'DEHA') are mixed with an organic solvent to form a one-component polymerization inhibitor into 1,3 Provides a method for preventing the polymerization of butadiene.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention relates to a polymerization inhibitor of 1,3-butadiene, comprising 4-tertary-butylcatechol (TBC), diethyl hydroxylamine (DEHA), and an organic solvent.

When the polymerization inhibitor according to the present invention is introduced into the distillation unit where the gas and liquid of the extractive distillation column coexist, it is mixed with the fluid at the top of the distillation to efficiently remove the polymerization initiator such as free radicals and oxygen, and the polymer is already advanced. In order to be able to remove the activity of the polymerization inhibitor, the mixing ratio of the polymerization agent is 9.0 to 30.0% by weight of 4- tert-butylcatechol (TBC), 50.0 to 90.0% by weight of diethyl hydroxylamine (DEHA) and 1.0 It is preferable that it is an organic solvent of -20.0 weight%.

The organic solvent has an excellent solubility in 4-tertiary-butylcatechol (TBC) and diethyl hydroxylamine (DEHA), which acts as a polymerization inhibitor, and affects the purity of 1,3-butadiene as a final product. It is selected from solvents that do not give. The organic solvent is preferably selected from alcohols having 3 to 5 carbon atoms, and more preferably isobutyl alcohol (hereinafter referred to as 'IBA') having the same structure as the following general formula 1 or the following general formula 2 It is selected from isopropyl alcohol (hereinafter referred to as 'IPA') having a structure such as.

(Formula 1)

(Formula 2)

The isobutyl alcohol (IBA) and the isopropyl alcohol (IPA) can dissolve both 4-tertiary-butylcatechol and diethyl hydroxylamine components and are used as a solvent without affecting the process or the product.

The 4-tert-butylcatechol (TBC) has a structure as shown in the following general formula (3).

(Formula 3)

The molecular formula of the 4-tert-butylcatechol (TBC) is C ₆ H ₃ (OH) ₂ C (CH ₃ ) ₃ , the state is a white to pale yellow solid, the boiling point is 285 ℃, melting point is 53 ℃, Specific gravity is 1,049 / 60 ° C and viscosity is 36 cps / 60 ° C. It is widely used as a polymerization inhibitor of liquid 1,3-butadiene and styrene products alone, and is manufactured from catechol, isobutylene, p-tertiary-butylphenol, chlorine, and caustic soda. By catechol method of butylation with isobutylene in the presence of an acid catalyst to prepare TBC, or by chlorination of pt-butylphenol (PTBP) to give 2-chloro-4-tert-butylphenol, followed by caustic soda It can be prepared by the p- tert-butylphenol (PTBP) method of replacing chlorine with a hydroxyl group.

4-tertiary-butylcatechol (TBC) has a low vapor pressure and thus exhibits a good anti-polymerization effect in the process part of the liquid environment.

The diethyl hydroxylamine (DEHA) has the structure shown in the following general formula (4).

(Formula 4)

The molecular formula of the diethyl hydroxylamine (DEHA) is (C ₂ H ₅ ) ₂ NOH, the state is a liquid, it is widely used as a deoxidant in boiler water and petrochemical processes.

Diethyl hydroxylamine (DEHA) is capable of removing oxygen in the process portion and thus exhibits an anti-polymerization effect in the gaseous process portion.

The present invention also provides a method of preventing polymerization by inhibiting polymer production of 1,3-butadiene in the extraction distillation step in the preparation of 1,3-butadiene.

Specifically, the present invention provides a method for preventing the polymerization of 1,3-butadiene, which prevents the formation of polymers in gaseous and liquid environments and further removes the activity of polymers already produced. More specifically, the present invention is directed to extractive distillation of 1,3-butadiene from mixed C ₄ fraction in an extractive distillation column, 4-tertiary-butylcatechol (TBC), diethyl hydroxylamine (DEHA) and organic solvents. It provides a method for preventing the polymerization of 1,3-butadiene, characterized in that the one-component polymerization inhibitor is added to the extraction distillation column.

The organic solvent can dissolve both 4-tertiary-butylcatechol and diethyl hydroxylamine components, and alcohols having 3 to 5 carbon atoms are used as a solvent which does not affect a process or a product. In particular, the alcohols are preferably isobutyl alcohol (IBA) or isopropyl alcohol (IPA).

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

1 is an extractive distillation process diagram for the production of 1,3-butadiene including a process in which the polymerization inhibitor of the present invention is injected. Referring to Figure 1 in detail with respect to the polymerization prevention method of 1,3-butadiene in the 1,3-butadiene manufacturing process according to the present invention.

As shown in Fig. 1, the extractive distillation column 1 is in the form of a 61-stage tray and a two-stage chimney tray 1-a and 1-b. The mixed C ₄ fraction added to the extractive distillation column (1) is gaseous, 1,3-butadiene (83 to 84% by weight), vinyl acetylene (Vinyl Actylene), ethyl acetylene, 1,2-butadiene Consisting of (1,2-Butadiene), methyl acetylene and C ₅ fractions, through mixed C ₄ fraction inputs (2) into the first chimney tray (1-a) of the extractive distillation column 27-28 It is fed in tons / hour. In addition, dimethylformamide as an extraction solvent is introduced into the dimethylformamide inlet 3 formed in the 11-stage tray of the extractive distillation column 1 at 45 to 47 tons / hour.

The polymerization inhibitor according to the present invention is transferred from the polymerization storage tank (4) by the polymerization injection pump (5) and introduced into the upper transfer pipe of the extraction distillation column (1) and / or into the dimethylformamide injection pipe. The dimethylformamide is introduced into the extractive distillation column 1 through the dimethylformamide input unit 3 together with the solvent dimethylformamide.

1,3-butadiene having low solubility in dimethylformamide as an extraction solvent in the mixed C ₄ fraction added to the extractive distillation column (1) is first purified and moved to the upper portion of the extractive distillation column (1). The concentration of 1,3-butadiene at the top of the extractive distillation column 1 is 95-98%. In addition, the temperature and pressure of the upper part of the extraction distillation column 1 are 36-38.5 degreeC and 3.10-3.15 kg / cm <2> G, respectively.

On the other hand, vinyl acetylene, ethyl acetylene, 1,2-butadiene, methyl acetylene and C ₅ fractions having similar boiling points to 1,3-butadiene in the mixed C ₄ fraction and having good solubility in the extraction solvent (dimethylformamide) are the dimethyl It is dissolved in formamide and moved to the bottom of the extractive distillation column (1). The concentration of 1,3-butadiene in the bottom of the extractive distillation column 1 is 5.3 to 5.5%. In addition, the temperature and pressure of the lower part of the extractive distillation column 1 are 130-130 degreeC and 3.9-4.0 kg / cm <2> G.

The purified C ₄ fraction from the top of the extractive distillation column (1) is phase-changed to liquid in the condenser (6) and paused in the condensation drum (7). It is then transferred to a 4 L reflux pump strainer 8 to remove the 1,3-butadiene polymer (fouling material) generated in the purified C ₄ fraction. Subsequently, a portion of the purified C ₄ fraction is re-introduced into the extractive distillation column (1) by the reflux pump (9) to increase the concentration of 1,3-butadiene in the mixed C ₄ fraction present on the upper portion of the extractive distillation column (1). 98%, while most of the purified C ₄ fraction is passed to the subsequent 1,3-butadiene purification process.

Meanwhile, a mixture of dimethylformamide, 1,3-butadiene, vinyl acetylene, ethyl acetylene, 1,2-butadiene, methyl acetylene, and C ₅ fractions from the bottom of the extractive distillation column (1) is transferred to the bottom strainer (10). Migrate to remove 1,3-butadiene polymer (fouling material). It is then sent by pressure to the subsequent 1,3-butadiene recovery process (b) to recover 5.3-5.5% of 1,3-butadiene remaining in the mixture of the extraction solvent and the mixed C ₄ fraction.

Since the internal condition of the extractive distillation column (1) cannot be normally checked, the state and accumulation amount of the polymer produced in the reflux pump strainer (8) and the column lower strainer (10), which can be opened during normal operation, are 1,3 It is a measure of the degree of polymerization and fouling of butadiene.

If no proper measures are taken to prevent the polymerization of 1,3-butadiene, resin or rubbery polymers (fouling materials) caused by polymerization of 1,3-butadiene on or below the extraction distillation column (1) ) Block the extractive distillation column 1, which causes the extractive distillation column 1 to explode or shut down and even stop the associated plant operation.

 When the polymerization inhibitor of the present invention is introduced into the upper portion of the extractive distillation column (1) by a supply means, the free radicals and oxygen present on the upper portion of the extractive distillation column (1) must be mixed with the fluid (gas and liquid) of the upper portion of the distillation at a desired composition ratio. It is possible to more efficiently remove the activity of the polymerization initiator and the advanced polymer such as, and to remove the activity of the polymerized and advanced polymer of 1,3-butadiene generated under the extraction distillation column (1). Therefore, in the method for preventing the polymerization of 1,3-butadiene according to the present invention, the mixing ratio is 9.0 to 30.0% by weight of 4- tert-butylcatechol (TBC), 50.0 to 90.0% by weight of diethyl hydroxylamine ( It is preferable to add a one-component polymerization inhibitor in which DEHA) and 1.0 to 20.0% by weight of an organic solvent are mixed into the extractive distillation column (1).

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are merely illustrative as specific embodiments of the present invention and should not be understood as limiting the scope of the present invention.

Example 1

30 ppm of polymerization inhibitor (mixed C ₄ ), made by mixing 15 wt% 4-tertary-butylcatechol (TBC), 75 wt% diethyl hydroxylamine (DEHA) and 10 wt% isobutyl alcohol (IBA) To the top of the extractive distillation column in which gas and liquid coexist through an anti-polymerization injection pump, and the condition and accumulation amount of the accumulated polymer are periodically tested and the results are shown in Table 1.

Example 2

The composition and mixing ratio of the polymerization inhibitor were 15% by weight 4-tertary-butylcatechol (TBC), 75% by weight diethyl hydroxylamine (DEHA) and 10% by weight isopropyl alcohol (IPA). In the same manner as in Example 1, the state and accumulation amount of the polymer were periodically tested, and the results are shown in Table 1.

Comparative Example 1

Except not using a polymerization inhibitor, the state and accumulation amount of the polymer were periodically tested in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2

Periodically test the condition and accumulation of the polymer in the same manner as in Example 1, except that 30 ppm of the TBC-only polymerization inhibitor (compared to the mixed C ₄ input amount) was injected into the top of the extraction distillation column through the polymerization injection pump. The results are shown in Table 1.

Comparative Example 3

Periodically test the condition and accumulation of the polymer in the same manner as in Example 1, except that 30 ppm of the polymerization inhibitor of DEHA alone (compared to the amount of mixed C ₄ ) was introduced to the top of the extraction distillation column through the polymerization injection pump. The results are shown in Table 1.

Polymer accumulation Polymer state Process status Example 1 1ℓ / 14 months Flowable Rubber Type Normal driving Example 2 1ℓ / 13 months Flowable Rubber Type Normal driving Comparative Example 1 1ℓ / 0.5 months Resin Emergency shutdown after two months Comparative Example 2 1ℓ / 2 months Rubber Emergency shutdown after 17 months Comparative Example 3 1ℓ / 1 month Resin Emergency shutdown after 11 months

(Evaluation results)

According to the progress of the polymerization reaction of 1,3-butadiene in the extraction distillation process of 1,3-butadiene, the state of the polymer (fouling material) is a flowable rubber type having a low molecular weight, a rubber type having a medium molecular weight, and a large molecular weight. Appear as terrain The smaller the molecular weight of the resulting polymer (fouling material), the lower the degree of polymerization of 1,3-butadiene.

When the polymerization inhibitor was not added as in Comparative Example 1, an emergency shutdown situation of the plant occurred due to the increase in pressure of the extractive distillation column after two months due to the production of a high-speed resin type polymer.

When only 4-tertiary-butylcatechol (TBC) was added alone as in Comparative Example 2, the pressure rise of the extractive distillation column occurred after 17 months due to the production of a rubber polymer, and the 1,3-butadiene plant Emergency stop for safe operation.

In addition, when only diethyl hydroxylamine (DEHA) alone was added as in Comparative Example 3, a pressure rise of the extractive distillation column occurred after 11 months due to the production of a resin polymer, resulting in an emergency shutdown of the plant.

On the other hand, as in Examples 1 and 2 with an organic solvent such as 4-tertary-butylcatechol (TBC), diethyl hydroxylamine (DEHA) and isopropyl alcohol (IPA) or isobutyl alcohol (IBA) When the polymerization inhibitor according to the present invention is added, the polymerization prevention effect of 1,3-butadiene at the same time is excellent in the liquid and gaseous environment compared to the case of using the conventional single component polymerization inhibitor as in Comparative Examples 2 and 3. After three years, stable continuous operation of the extractive distillation column was possible until the operation was stopped for regular maintenance.

As described above, the polymerization inhibitor according to the present invention having the excellent polymerization inhibition and antifouling effect is a liquid and gaseous phase during the production process for separating and producing 1,3-butadiene, which is a raw material of various rubbers and synthetic resins in mixed C ₄ fractions. By inhibiting the polymerization of 1,3-butadiene over a wide temperature range, high purity 1,3-butadiene products can be extracted and distilled.

In addition, the polymerization prevention method according to the present invention has the advantage of preventing the emergency stop of the 1,3-butadiene production plant that may be caused by fouling in advance, and enables a safe operation for a long time.

Claims (8)

It is composed of 4-tert-butylcatechol, diethyl hydroxylamine and an organic solvent, wherein the organic solvent is selected from alcohols having 3 to 5 carbon atoms. The method according to claim 1, wherein the mixing ratio is 9.0 to 30.0% by weight of 4-tertiary-butylcatechol, 50.0 to 90.0% by weight of diethyl hydroxylamine and 1.0 to 20.0% by weight of an organic solvent. , 3-butadiene polymerization inhibitor. delete The polymerization inhibitor of 1,3-butadiene according to claim 1, wherein the alcohols are isopropyl alcohol or isobutyl alcohol. In extractive distillation of 1,3-butadiene from mixed C4 fraction in an extractive distillation column, it is composed of an organic solvent selected from 4-tert-butylcatechol, diethyl hydroxylamine, and alcohol having 3 to 5 carbon atoms. A method for preventing polymerization of 1,3-butadiene, wherein a one-component polymerization inhibitor is introduced into the extractive distillation column. 6. The one-component polymerization inhibitor according to claim 5, wherein the mixing ratio is 9.0 to 30.0% by weight of 4-tertiary-butylcatechol, 50.0 to 90.0% by weight of diethyl hydroxylamine and 1.0 to 20.0% by weight of an organic solvent. Method for preventing the polymerization of 1,3-butadiene, characterized in that the addition. delete The method for preventing polymerization of 1,3-butadiene according to claim 5, wherein the alcohols are isopropyl alcohol or isobutyl alcohol.

Images