A method and device system for extracting alpha-methylstyrene from phenol-ketone tar cracking products

Abstract

The present invention provides a method and device system for extracting alpha-methylstyrene from phenol-ketone tar cracking products, the method comprising pretreatment, catalytic cracking, dehydration treatment, ethylbenzene distillation, isopropylbenzene distillation and azeotropic distillation carried out in sequence, and the azeotropic light component obtained by the azeotropic distillation is subjected to alpha-methylstyrene distillation, and the heavy component is subjected to phenol distillation; wherein the pretreatment is used to separate phenol and acetophenone in phenol-ketone tar; water is added during the azeotropic distillation to form an azeotropic light component containing alpha-methylstyrene. The method provided by the present invention obtains ethylbenzene, isopropylbenzene and phenol products while extracting high-purity alpha-methylstyrene, effectively avoiding the problem that alpha-methylstyrene and phenol form a minimum azeotrope causing the alpha-methylstyrene product to have a low purity, which is conducive to promoting further research on the resource utilization of phenol-ketone tar and the improvement of the economic efficiency of phenol-ketone devices.

Description

Technical Field

[0001] The invention belongs to the field of petrochemical industry and relates to a method for recovering phenol-ketone tar, in particular to a method for extracting alpha-methylstyrene from phenol-ketone tar cracking products and a device system thereof. Background Art

[0002] As is known to all, the process of producing phenol and acetone by using the cumene method will produce phenol-ketone tar as a by-product. In addition to a certain amount of light components such as phenol and acetophenone, phenol-ketone tar also contains α,α-dimethylbenzyl alcohol, β-methylphenylethanol, α-methylstyrene dimer, 2-cumylphenol, 4-cumylphenol, biphenol and heavy components with larger molecular weight. Since the composition of phenol-ketone tar is complex and the separation of each component is difficult, it is usually used as a fuel to directly burn it in industrial production to produce steam as a by-product.

[0003] In order to avoid the environmental problems caused by incineration and improve the economic value of phenol-ketone tar, technicians usually first separate and purify the light components such as phenol and acetophenone in phenol-ketone tar, and then crack the α-methylstyrene dimer, 2-cumylphenol, 4-cumylphenol and other components in the remaining tar to generate products such as cumene, α-methylstyrene (AMS), phenol, etc., thereby improving the overall value of tar. The cracking of α-methylstyrene dimer will also generate impurities such as ethylbenzene, butylbenzene, and sec-butylbenzene. However, due to the complex composition of tar, the composition of the light components generated by the cracking reaction is also complex, and multiple steps of distillation operations are required to obtain cracking products with higher purity.

[0004] CN116272713A discloses a method for recovering AMS by cracking phenol tar. The phenol tar is recombined and cracked by a cracking kettle, and the light component vapor is extracted and condensed through the top of the reactor. After condensation, the light component is distilled twice to obtain AMS with a content of more than 99%. However, the article does not mention the separation method of phenol, another important cracking product. Usually, the cracking of phenol ketone tar will also produce a large amount of phenol. Since phenol and AMS form a minimum azeotrope, effective separation cannot be achieved by distillation. Therefore, the application of the above patent still has great limitations.

[0005] CN1065854C discloses a method for separating a mixture of water, AMS and phenol. In the fractionation section, the phenol content in AMS is reduced by controlling the pH of the water phase distilled from the top of the tower with alkali. However, even if the pH is greater than 11, the oil phase distilled from the top of the tower still contains a relatively high content of phenol, making it difficult to obtain a high-purity AMS product.

[0006] It can be seen that how to provide a method suitable for separating the cracking products of phenol-ketone tar to obtain high-purity AMS products is of great significance for further research on the resource utilization of phenol-ketone tar and improving the economic efficiency of phenol-ketone equipment. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method and an apparatus system for extracting α-methylstyrene from the cracking products of phenol-ketone tar, which can obtain ethylbenzene, isopropylbenzene and phenol products while extracting high-purity α-methylstyrene, which is conducive to promoting further research on the resource utilization of phenol-ketone tar and improving the economic efficiency of phenol-ketone equipment.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for extracting α-methylstyrene from phenol-ketone tar cracking products, the method comprising pretreatment, catalytic cracking, dehydration treatment, ethylbenzene distillation, isopropylbenzene distillation and azeotropic distillation performed in sequence, and the azeotropic light components obtained by the azeotropic distillation are subjected to α-methylstyrene distillation, and the heavy components are subjected to phenol distillation.

[0010] The pretreatment is used to separate phenol and acetophenone in phenol-ketone tar; water is added during the azeotropic distillation process to form an azeotropic light component containing α-methylstyrene.

[0011] The method provided by the present invention pre-treats phenol-ketone tar before catalytic cracking to separate phenol and acetophenone therein, thereby avoiding the dehydration polymerization reaction of acetophenone to generate water and macromolecular polymers during the subsequent cracking process, and at the same time avoiding the presence of a large amount of acetophenone that makes the separation of cracking products more difficult, and finally obtaining a high-purity cracking product.

[0012] In addition, the present invention adds water during the azeotropic distillation process, so that water forms an azeotropic light component with α-methylstyrene, sec-butylbenzene, butylbenzene, etc., and subsequently obtains high-purity α-methylstyrene through α-methylstyrene distillation, which effectively avoids the problem that α-methylstyrene and phenol form a minimum azeotrope and are difficult to separate, and reduces the content of difficult-to-separate impurities (such as butylbenzene and sec-butylbenzene) in the α-methylstyrene product. The purity of the α-methylstyrene product finally obtained can reach more than 99.9wt%, and ethylbenzene, isopropylbenzene and phenol products are obtained at the same time, which fully promotes the further research on the resource utilization of phenol-ketone tar and the improvement of the economic efficiency of the phenol-ketone device.

[0013] Preferably, the phenol-ketone tar is a heavy component tar produced as a by-product in the process of producing phenol and acetone by the isopropylbenzene process, and its specific components include: 5-7wt% of phenol, 2-4wt% of α,α-dimethylbenzyl alcohol, 1-2wt% of β-methylphenethyl alcohol, 18-25wt% of acetophenone, 8-9wt% of α-methylstyrene dimer, 3-4.5wt% of 2-cumylphenol, 19.5-22.5wt% of 4-cumylphenol, and 26-40wt% of other inevitable components.

[0014] Preferably, the reaction temperature of the catalytic cracking is 250-350°C, the absolute pressure is 60-150 kPa, and the reaction time is 5-20 h.

[0015] Preferably, the temperature of the dehydration treatment is 50-115° C., the absolute pressure is 10-90 kPa, and the water content of the obtained product is ≤0.5 wt %.

[0016] Preferably, the temperature of the ethylbenzene distillation is 70-110° C., the absolute pressure is 5-40 kPa, and the purity of the obtained ethylbenzene product is ≥99.5wt%.

[0017] Preferably, the temperature of the cumene distillation is 80-120° C., the absolute pressure is 1-30 kPa, and the purity of the obtained cumene product is ≥99.8wt%.

[0018] Preferably, the temperature of the azeotropic distillation is 55-125° C., the absolute pressure is 20-100 kPa, and the mass ratio of water to material is (0.5-5):1.

[0019] Preferably, the temperature of the α-methylstyrene distillation is 95-105° C., the absolute pressure is 5-40 kPa, and the purity of the obtained α-methylstyrene product is ≥99.9wt%.

[0020] Preferably, the temperature of the phenol distillation is 110-130° C., the absolute pressure is 1-30 kPa, and the purity of the obtained phenol product is ≥99.8wt%.

[0021] In a second aspect, the present invention provides an apparatus system adopted by the method as described in the first aspect, wherein the apparatus system comprises a cracking product tank, a dehydration tower, an ethylbenzene distillation tower, an isopropylbenzene distillation tower and an azeotropic distillation tower connected in sequence, and the top of the azeotropic distillation tower is connected to an α-methylstyrene distillation tower, and the bottom of the tower is connected to a phenol distillation tower.

[0022] Preferably, the number of theoretical plates of the dehydration tower is 20-60, a separatory tank is provided on the top of the tower, and an interface meter is provided in the separatory tank.

[0023] Preferably, the ethylbenzene distillation tower has 40-70 theoretical plates.

[0024] Preferably, the cumene distillation tower has 40-70 theoretical plates.

[0025] Preferably, the azeotropic distillation tower has 50-100 theoretical plates, a separatory tank is provided at the top of the tower, and an interface meter is provided in the separatory tank.

[0026] Preferably, the α-methylstyrene distillation tower has 30-70 theoretical plates.

[0027] Preferably, the phenol distillation tower has 20-50 theoretical plates.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The method provided by the present invention pre-treats the phenol-ketone tar before catalytic cracking to separate phenol and acetophenone therein, thereby avoiding the dehydration polymerization reaction of acetophenone to generate water and macromolecular polymers during the subsequent cracking process, and at the same time avoiding the presence of a large amount of acetophenone that makes the separation of the cracking products more difficult, and finally obtaining a high-purity cracking product.

[0030] (2) The present invention adds water during the azeotropic distillation process, so that water forms an azeotropic light component with α-methylstyrene, sec-butylbenzene, butylbenzene, etc., and then obtains high-purity α-methylstyrene through subsequent distillation of α-methylstyrene, which effectively avoids the problem that α-methylstyrene and phenol form a minimum azeotrope and are difficult to separate, and reduces the content of difficult-to-separate impurities (such as butylbenzene and sec-butylbenzene) in the α-methylstyrene product. The purity of the final α-methylstyrene product can reach more than 99.9wt%, and ethylbenzene, isopropylbenzene and phenol products are obtained at the same time, which fully promotes the further research on the resource utilization of phenol-ketone tar and the improvement of the economic efficiency of phenol-ketone equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention provides a schematic diagram of the structure of a device system for extracting α-methylstyrene from phenol-ketone tar cracking products.

[0032] Among them: 1- cracking product tank; 2- dehydration tower; 3- ethylbenzene distillation tower; 4- isopropylbenzene distillation tower; 5- azeotropic distillation tower; 6- AMS distillation tower; 7- phenol distillation tower; 8- condenser; 9- liquid separation tank; 10- interface meter; 11- water sampling pump; 12- material receiving tank. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0034] A certain embodiment of the present invention provides a method for extracting α-methylstyrene from phenol-ketone tar cracking products, the method comprising pretreatment, catalytic cracking, dehydration treatment, ethylbenzene distillation, isopropylbenzene distillation and azeotropic distillation performed in sequence, and the azeotropic light components obtained by the azeotropic distillation are subjected to α-methylstyrene distillation, and the heavy components are subjected to phenol distillation.

[0035] The pretreatment is used to separate phenol and acetophenone in phenol-ketone tar; water is added during the azeotropic distillation process to form an azeotropic light component containing α-methylstyrene.

[0036] In the present invention, the pretreatment may be vacuum distillation, as long as effective separation of phenol and acetophenone in phenol-ketone tar can be achieved, so the specific process parameters of vacuum distillation are not particularly limited herein.

[0037] The method provided by the present invention pre-treats phenol-ketone tar before catalytic cracking to separate phenol and acetophenone therein, thereby avoiding the dehydration polymerization reaction of acetophenone to generate water and macromolecular polymers during the subsequent cracking process, and at the same time avoiding the presence of a large amount of acetophenone that makes the separation of cracking products more difficult, and finally obtaining a high-purity cracking product.

[0038] In addition, the present invention adds water during the azeotropic distillation process, so that water forms an azeotropic light component with α-methylstyrene, sec-butylbenzene, butylbenzene, etc., and subsequently obtains high-purity α-methylstyrene through α-methylstyrene distillation, which effectively avoids the problem that α-methylstyrene and phenol form a minimum azeotrope and are difficult to separate, and reduces the content of difficult-to-separate impurities (such as butylbenzene and sec-butylbenzene) in the α-methylstyrene product. The purity of the α-methylstyrene product finally obtained can reach more than 99.9wt%, and ethylbenzene, isopropylbenzene and phenol products are obtained at the same time, which fully promotes the further research on the resource utilization of phenol-ketone tar and the improvement of the economic efficiency of the phenol-ketone device.

[0039] In certain embodiments, the phenol-ketone tar is a heavy component tar produced as a by-product in the process of producing phenol and acetone by the isopropylbenzene process, and the specific components include: 5-7wt% phenol, 2-4wt% α,α-dimethylbenzyl alcohol, 1-2wt% β-methylphenethanol, 18-25wt% acetophenone, 8-9wt% α-methylstyrene dimer, 3-4.5wt% 2-cumylphenol, 19.5-22.5wt% 4-cumylphenol, and 26-40wt% of other inevitable components.

[0040] The content of phenol is 5-7wt%, for example, 5wt%, 5.2wt%, 5.4wt%, 5.6wt%, 5.8wt%, 6wt%, 6.2wt%, 6.4wt%, 6.6wt%, 6.8wt% or 7wt%, and the content of α,α-dimethylbenzyl alcohol is 2-4wt%, for example, 2wt%, 2.2wt%, 2.4wt%, 2.6wt%, 2.8wt%, 3wt%, 3.2wt%, 3.4wt%, 3.6wt%, 3.8 wt% or 4wt%, the content of β-methylphenethyl alcohol is 1-2wt%, for example, it can be 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2wt%, the content of acetophenone is 18-25wt%, for example, it can be 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt% or 25wt%, the content of α-methylphenethyl alcohol is 1-2wt%, for example, it can be 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2wt%, the content of acetophenone is 18-25wt%, for example, it can be 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt% or 25wt%, The content of olefin dimer is 8-9wt%, for example, 8wt%, 8.1wt%, 8.2wt%, 8.3wt%, 8.4wt%, 8.5wt%, 8.6wt%, 8.7wt%, 8.8wt%, 8.9wt% or 9wt%, the content of 2-cumylphenol is 3-4.5wt%, for example, 3wt%, 3.2wt%, 3.4wt%, 3.6wt%, 3.8wt%, 4wt%, 4.2wt%, 4.4wt% or 4.5wt%, the content of 4-cumylphenol is The content of phenol is 19.5-22.5wt%, for example, it can be 19.5wt%, 20wt%, 20.5wt%, 21wt%, 21.5wt%, 22wt% or 22.5wt%, and the content of other inevitable components is 26-40wt%, for example, it can be 26wt%, 28wt%, 30wt%, 32wt%, 34wt%, 36wt%, 38wt% or 40wt%, but it is not limited to the listed values, and other unlisted values ​​within this numerical range are equally applicable.

[0041] In the present invention, the α-methylstyrene dimer may be an AMS cyclic dimer (see the following formula 1) and / or an AMS linear dimer (see the following formulas 2 and 3), and the specific chemical formula is as follows:

[0042]

[0043] In certain embodiments, the reaction temperature of the catalytic cracking is 250-350°C, for example, it can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C or 350°C, the absolute pressure is 60-150kPa, for example, it can be 60kPa, 70kPa, 80kPa, 90kPa, 100kPa, 110kPa, 120kPa, 130kPa, 140kPa or 150kPa, and the reaction time is 5-20h, for example, it can be 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h or 20h, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] In the present invention, the specific components of the cracking products in the light components obtained after catalytic cracking of phenol-ketone tar mainly include: 30-39wt% of α-methylstyrene, 28-35wt% of phenol, 12-15wt% of isopropylbenzene, 4-8wt% of ethylbenzene, 0.3-1.1wt% of sec-butylbenzene, 0.1-0.5wt% of butylbenzene, and 5-10wt% of others.

[0045] In some embodiments, the temperature of the dehydration treatment is 50-115°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or 115°C, and the absolute pressure is 10-90kPa, for example, 10kPa, 15kPa, 20kPa, 25kPa, 30kPa, 35kPa, 40kPa, 45kPa, 50kPa, 55kPa, 60kPa, 65kPa, 70kPa, 75kPa, 80kPa, 85kPa or 90kPa, the moisture content of the obtained product is ≤0.5wt%, for example, it can be 0.05wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.45wt% or 0.5wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In the present invention, the dehydration treatment is carried out under negative pressure conditions, which fully removes the water in the cracking product, thereby avoiding the formation of multi-element azeotropes between water and ethylbenzene, isopropylbenzene, AMS, etc., and improving the purity of the main product obtained by subsequent ethylbenzene distillation.

[0047] In certain embodiments, the temperature of the ethylbenzene distillation is 70-110°C, for example, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C or 110°C, and the absolute pressure is 5-40kPa, for example, 5kPa, 10kPa, 15kPa, 20kPa, 25kPa, 30kPa, 35kPa or 40kPa, and the purity of the obtained ethylbenzene product is ≥99.5wt%, for example, 99.5wt%, 99.6wt%, 99.7wt%, 99.8wt% or 99.9wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] In certain embodiments, the temperature of the cumene distillation is 80-120°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, and the absolute pressure is 1-30kPa, for example, 1kPa, 2kPa, 4kPa, 6kPa, 8kPa, 10kPa, 12kPa, 14kPa, 16kPa, 18kPa, 20kPa, 22kPa, 24kPa, 26kPa, 28kPa or 30kPa, and the purity of the obtained cumene product is ≥99.8wt%, for example, 99.8wt%, 99.82wt%, 99.84wt%, 99.86wt%, 99.88wt% or 99.9wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] In certain embodiments, the temperature of the azeotropic distillation is 55-125°C, for example, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C or 125°C, and the absolute pressure is 20-100 kPa, for example, 20 kPa, 25 kPa, 30 kPa, 35 kPa, 40 kPa, 45 kPa, 50 kPa, 55 kPa Pa, 60kPa, 65kPa, 70kPa, 75kPa, 80kPa, 85kPa, 90kPa, 95kPa or 100kPa, the mass ratio of water to material is (0.5-5):1, for example, it can be 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] In certain embodiments, the temperature of the α-methylstyrene distillation is 95-105°C, for example, it can be 95°C, 96°C, 97°C, 98°C, 99°C, 100°C, 101°C, 102°C, 103°C, 104°C or 105°C, and the absolute pressure is 5-40kPa, for example, it can be 5kPa, 10kPa, 15kPa, 20kPa, 25kPa, 30kPa, 35kPa or 40kPa, and the purity of the obtained α-methylstyrene product is ≥99.9wt%, for example, it can be 99.9wt%, 99.91wt%, 99.92wt%, 99.93wt%, 99.94wt%, 99.95wt%, 99.96wt%, 99.97wt%, 99.98wt% or 99.99wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0051] In certain embodiments, the temperature of the phenol distillation is 110-130°C, for example, it can be 110°C, 112°C, 114°C, 116°C, 118°C, 120°C, 122°C, 124°C, 126°C, 128°C or 130°C, the absolute pressure is 1-30kPa, for example, it can be 1kPa, 2kPa, 4kPa, 6kPa, 8kPa, 10kPa, 12kPa, 14kPa, 16kPa, 18kPa, 20kPa, 22kPa, 24kPa, 26kPa, 28kPa or 30kPa, and the purity of the obtained phenol product is ≥99.8wt%, for example, it can be 99.8wt%, 99.82wt%, 99.84wt%, 99.86wt%, 99.88wt% or 99.9wt%, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] A certain embodiment of the present invention provides an apparatus system used in the above method, wherein the apparatus system includes a cracking product tank, a dehydration tower, an ethylbenzene distillation tower, an isopropylbenzene distillation tower and an azeotropic distillation tower connected in sequence, and the top of the azeotropic distillation tower is connected to an α-methylstyrene distillation tower, and the bottom of the tower is connected to a phenol distillation tower.

[0053] In some embodiments, the theoretical number of plates of the dehydration tower is 20-60, for example, 20, 25, 30, 35, 40, 45, 50, 55 or 60, a separatory tank is provided on the top of the tower, and an interface meter is provided in the separatory tank.

[0054] The present invention provides a separator tank at the top of the dehydration tower, so that the condensed material at the top of the tower enters the separator tank, and the oil-water two-phase is separated into layers. An interface meter is provided in the separator tank to monitor the liquid level of the oil-water two-phase interface in the separator tank. The water phase of the separator tank is extracted from the system through a pump, and the output power of the water extraction pump is interlocked with the interface liquid level of the separator tank to prevent the oil phase from being extracted from the system. Finally, the oil phase returns to the dehydration tower.

[0055] In certain embodiments, the theoretical number of plates of the ethylbenzene distillation tower is 40-70, for example, 40, 45, 50, 55, 60, 65 or 70, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] In certain embodiments, the theoretical number of plates of the cumene distillation tower is 40-70, for example, 40, 45, 50, 55, 60, 65 or 70, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] In certain embodiments, the theoretical number of plates of the azeotropic distillation tower is 50-100, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100, a separatory tank is provided at the top of the tower, and an interface meter is provided in the separatory tank.

[0058] The present invention provides a separatory tank at the top of the azeotropic distillation tower, so that the condensed material at the top of the tower enters the separatory tank, and the oil-water two-phase is separated into layers. An interface meter is provided in the separatory tank for monitoring the liquid level of the oil-water two-phase interface in the separatory tank. The water phase of the separatory tank is pumped into a recovered water receiving tank, and the recovered water is circulated for the azeotropic distillation tower. The output power of the water pump is interlocked with the interface liquid level of the separatory tank. The oil phase is an AMS crude product, which is extracted and enters an AMS crude product tank.

[0059] In certain embodiments, the theoretical plate number of the α-methylstyrene distillation tower is 30-70, for example, 30, 35, 40, 45, 50, 55, 60, 65 or 70, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In certain embodiments, the theoretical number of plates of the phenol distillation tower is 20-50, for example, 20, 25, 30, 35, 40, 45 or 50, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0061] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0062] Example 1

[0063] This embodiment provides a device system for extracting α-methylstyrene from phenol ketone tar cracking products, such as Figure 1 As shown, the device system includes a cracking product tank 1, a dehydration tower 2, an ethylbenzene distillation tower 3, an isopropylbenzene distillation tower 4 and an azeotropic distillation tower 5 which are connected in sequence, and the top of the azeotropic distillation tower 5 is connected to an AMS distillation tower 6, and the bottom of the tower is connected to a phenol distillation tower 7.

[0064] Among them, a condenser 8 and a separator tank 9 are arranged at the top of the dehydration tower 2. The condensed material at the top of the tower enters the separator tank 9, and the oil-water two-phase is separated. An interface meter 10 is arranged in the separator tank 9 to monitor the liquid level of the oil-water two-phase interface in the separator tank 9. The water phase of the separator tank 9 is produced through the pump production system, and the output power of the water production pump 11 is interlocked with the interface liquid level of the separator tank 9 to prevent the oil phase from being produced from the system. Finally, the oil phase returns to the dehydration tower, and the water phase enters the receiving tank 12.

[0065] Similarly, the top of the azeotropic distillation tower 5 is provided with a condenser 8 and a separator 9, the condensed material at the top enters the separator 9, the oil-water two-phase is separated, an interface meter 10 is provided in the separator 9, which is used to monitor the liquid level of the oil-water two-phase interface in the separator 9, the water phase of the separator 9 is pumped into the receiving tank 12, and the recovered water is circulated for the azeotropic distillation tower 5, the output power of the water pump 11 is interlocked with the interface liquid level of the separator 9, the oil phase is the AMS crude product, and enters the receiving tank 12 after being produced.

[0066] Specifically, the tops and side lines of the ethylbenzene distillation tower 3 , the isopropylbenzene distillation tower 4 , the AMS distillation tower 6 and the phenol distillation tower 7 are respectively provided with a condenser 8 and a material receiving tank 12 .

[0067] In this embodiment, the dehydration tower 2 has 50 theoretical plates; the ethylbenzene distillation tower 3 has 60 theoretical plates, and the side-line extraction plates are 50; the isopropylbenzene distillation tower 4 has 60 theoretical plates, and the side-line extraction plates are 50; the azeotropic distillation tower 5 has 70 theoretical plates; the AMS distillation tower 6 has 60 theoretical plates, and the side-line extraction plates are 50; the phenol distillation tower 7 has 30 theoretical plates, and the side-line extraction plates are 25.

[0068] Example 2

[0069] This embodiment provides a device system for extracting α-methylstyrene from phenol-ketone tar cracking products. The specific structure is the same as that of Example 1, and the only difference is that:

[0070] In this embodiment, the number of theoretical plates of the dehydration tower 2 is 30; the number of theoretical plates of the ethylbenzene distillation tower 3 is 50, and the number of side-line extraction plates is 40; the number of theoretical plates of the isopropylbenzene distillation tower 4 is 50, and the number of side-line extraction plates is 40; the number of theoretical plates of the azeotropic distillation tower 5 is 70; the number of theoretical plates of the AMS distillation tower 6 is 50, and the number of side-line extraction plates is 40; the number of theoretical plates of the phenol distillation tower 7 is 20, and the number of side-line extraction plates is 17.

[0071] Application Example 1

[0072] This application example uses the device system provided in Example 1 to extract α-methylstyrene from the cracking products of phenol-ketone tar. The phenol-ketone tar comes from the phenol-ketone device of Jiangsu Ruiheng New Materials Co., Ltd. The composition of the phenol-ketone tar is: 6.5wt% phenol, 20.1wt% acetophenone, 3.3wt% α,α-dimethylbenzyl alcohol, 1.7wt% β-methylphenethanol, 8.4wt% α-methylstyrene dimer, 4.1wt% 2-cumylphenol, 21.4wt% 4-cumylphenol, and 34.5wt% of other inevitable components.

[0073] The method provided in this application example specifically includes the following steps:

[0074] (1) Phenol-ketone tar is subjected to negative pressure distillation to separate phenol and acetophenone. The distillation pressure is controlled at 1 kPa. The fraction is a mixture of phenol and acetophenone, accounting for 26.5 wt% of the feed ratio. The remaining tar enters a cracking reactor (not shown in the figure). The reaction temperature is controlled at 300° C., the absolute pressure is 90 kPa, the reaction time is 8 h, and the cracking product vapor is condensed and enters the cracking product tank 1.

[0075] (2) The cracking products enter the dehydration tower 2, and the absolute pressure in the tower is controlled to be 15 kPa, the top temperature is 50.5±0.5°C, the bottom temperature is 88°C, and the water content of the bottom effluent is 0.12 wt%.

[0076] (3) The bottom discharge of the dehydration tower 2 enters the ethylbenzene distillation tower 3, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 71° C., the reflux ratio is 10:1, the side line temperature is 75° C., the reflux ratio is 5:1, the bottom temperature is 88° C., and the purity of the ethylbenzene product taken from the side line is 99.65 wt%.

[0077] (4) The bottom discharge of ethylbenzene distillation tower 3 enters isopropylbenzene distillation tower 4, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 86°C, the reflux ratio is 10:1, the side line temperature is 88°C, the reflux ratio is 5:1, the bottom temperature is 118°C, and the purity of the side line isopropylbenzene product is 99.93wt%.

[0078] (5) The bottom discharge of the isopropylbenzene distillation tower 4 enters the azeotropic distillation tower 5, and the absolute pressure in the tower is controlled to be 30 kPa. The mass ratio of water to the bottom material of the isopropylbenzene distillation tower 4 is 2:1. The tower top temperature is 70° C., the oil phase reflux ratio is 7:1, and the top water is recycled for azeotropic distillation. The top oil phase is AMS crude product, and the AMS crude product has a purity of 98.01 wt%, a sec-butylbenzene content of 1.52 wt%, a butylbenzene content of 0.21 wt%, and a phenol content of 0.05 wt%. The bottom temperature is 122° C.

[0079] (6) The crude AMS product enters the AMS distillation tower 6, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 96° C., the reflux ratio is 15:1, the side line temperature is 98° C., the reflux ratio is 5:1, the bottom temperature is 103° C., and the purity of the side line AMS product is 99.91 wt%.

[0080] (7) The bottom discharge of the azeotropic distillation tower 5 enters the phenol distillation tower 7, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 110° C., the reflux ratio is 5:1, the side line temperature is 114° C., the reflux ratio is 3:1, the bottom temperature is 130° C., and the purity of the side line phenol product is 99.95 wt%.

[0081] Application Example 2

[0082] This application example uses the device system provided in Example 2 to extract α-methylstyrene from the cracking products of phenol-ketone tar. The source and composition of the phenol-ketone tar are the same as those in Application Example 1, so they are not described here.

[0083] The method provided in this application example specifically includes the following steps:

[0084] (1) Phenol-ketone tar is subjected to negative pressure distillation to separate phenol and acetophenone. The distillation pressure is controlled at 5 kPa. The fraction is a mixture of phenol and acetophenone, accounting for 26.5 wt% of the feed ratio. The remaining tar enters a cracking reactor (not shown in the figure). The reaction temperature is controlled at 320° C., the absolute pressure is 100 kPa, the reaction time is 7 h, and the cracking product vapor is condensed and enters the cracking product tank 1.

[0085] (2) The cracking product enters the dehydration tower 2, and the absolute pressure in the tower is controlled to be 50 kPa, the top temperature is 79±1° C., the bottom temperature is 115° C., and the water content of the bottom effluent is 0.23 wt%.

[0086] (3) The bottom discharge of the dehydration tower 2 enters the ethylbenzene distillation tower 3, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 71° C., the reflux ratio is 15:1, the side line temperature is 75° C., the reflux ratio is 7:1, the bottom temperature is 101° C., and the purity of the ethylbenzene product taken from the side line is 99.79 wt%.

[0087] (4) The bottom discharge of ethylbenzene distillation tower 3 enters cumene distillation tower 4, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 86°C, the reflux ratio is 15:1, the side line temperature is 88°C, the reflux ratio is 7:1, the bottom temperature is 118°C, and the purity of the side line cumene product is 99.88wt%.

[0088] (5) The bottom discharge of the isopropylbenzene distillation tower 4 enters the azeotropic distillation tower 5, and the absolute pressure in the tower is controlled to be 20 kPa. The mass ratio of water to the bottom material of the isopropylbenzene distillation tower 4 is 3:2. The tower top temperature is 59° C., the oil phase reflux ratio is 10:1, and the top water is recycled for azeotropic distillation. The top oil phase is AMS crude product, and the AMS crude product has a purity of 98.22 wt%, a sec-butylbenzene content of 1.54 wt%, a butylbenzene content of 0.19 wt%, and a phenol content of 0.04 wt%. The tower bottom temperature is 115° C.

[0089] (6) The crude AMS product enters the AMS distillation tower 6, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 96° C., the reflux ratio is 20:1, the side line temperature is 98° C., the reflux ratio is 7:1, the bottom temperature is 103° C., and the purity of the side line AMS product is 99.93 wt%.

[0090] (7) The bottom discharge of the azeotropic distillation tower 5 enters the phenol distillation tower 7, and the absolute pressure in the tower is controlled to be 10 kPa, the top temperature is 110° C., the reflux ratio is 3:1, the side line temperature is 114° C., the reflux ratio is 2:1, the bottom temperature is 130° C., and the purity of the phenol product taken out of the side line is 99.91 wt%.

[0091] Comparative application example 1

[0092] This comparative application example does not set up the dehydration tower 2 on the basis of application example 1, that is, the cracking product directly enters the ethylbenzene distillation tower 3, and the remaining steps and conditions are the same as those of application example 1, so they are not repeated here.

[0093] After testing, the purity of the ethylbenzene product obtained in this comparative application example is 95.26wt%. This is because the presence of more water forms an azeotrope with isopropylbenzene and AMS, thereby causing the purity of ethylbenzene to be significantly reduced.

[0094] Comparative Application Example 2

[0095] This comparative application example does not set up the azeotropic distillation tower 5 on the basis of application example 1, that is, the bottom discharge of the isopropylbenzene distillation tower 4 directly enters the AMS distillation tower 6, and the bottom discharge of the AMS distillation tower 6 enters the phenol distillation tower 7. The remaining steps and conditions are the same as those in application example 1, so they are not repeated here.

[0096] After testing, the purity of the AMS product obtained in this comparative application example is 94.61wt%, and the main impurities and their contents are: 4.73wt% of phenol, 0.33wt% of sec-butylbenzene, and 0.12wt% of butylbenzene, indicating that AMS and phenol form a minimum azeotrope.

[0097] Comparative Application Example 3

[0098] In this comparative application example, based on comparative application example 2, the conditions of the AMS distillation tower 6 are changed to: the absolute pressure in the tower is 30 kPa, the tower top temperature is 115° C., and the side line extraction temperature is 118° C. The remaining steps and conditions are the same as those in comparative application example 2, so they are not repeated here.

[0099] After testing, the purity of the AMS product obtained in this comparative application example is 93.14wt%, wherein the product contains 6.72wt% of phenol, indicating that the change of distillation pressure has little effect on the azeotropic composition of AMS and phenol.

[0100] Comparative Application Example 4

[0101] This comparative application example does not pretreat the phenol-ketone tar on the basis of Application Example 1, that is, the phenol-ketone tar containing phenol and acetophenone directly enters the cracking reactor, and the remaining steps and conditions are the same as those in Application Example 1, so they are not repeated here.

[0102] After testing, the comparative application example extracted a mixture of phenol and acetophenone at the top of the phenol distillation tower 7, which contained 28.1wt% of phenol and 70.5wt% of acetophenone, and compared with Application Example 1, the comparative application example extracted heavy components at the bottom of the phenol distillation tower 7 increased by 11.6wt%, indicating that the acetophenone in the phenol-ketone tar undergoes side reactions during cracking and subsequent separation to generate impurities with larger molecular weight.

[0103] Comparative Application Example 5

[0104] In this comparative application example, water is not added to the azeotropic distillation tower 5 on the basis of application example 1, and the remaining steps and conditions are the same as those of application example 1, so they are not described in detail here.

[0105] After testing, the purity of the AMS product obtained in this comparative application example is 94.25wt%, which contains 5.34wt% phenol, indicating that when water is not used for azeotropic distillation, phenol in AMS cannot be effectively removed, thereby reducing the purity of the AMS product.

[0106] It can be seen that the method provided by the present invention pretreats the phenol-ketone tar before catalytic cracking to separate phenol and acetophenone therein, thereby avoiding the dehydration polymerization reaction of acetophenone to generate water and macromolecular polymers during the subsequent cracking process, and at the same time avoiding the presence of a large amount of acetophenone that makes the separation of the cracking products more difficult, and finally obtaining a high-purity cracking product.

[0107] In addition, the present invention adds water during the azeotropic distillation process, so that water forms an azeotropic light component with α-methylstyrene, sec-butylbenzene, butylbenzene, etc., and subsequently obtains high-purity α-methylstyrene through α-methylstyrene distillation, which effectively avoids the problem that α-methylstyrene and phenol form a minimum azeotrope and are difficult to separate, and reduces the content of difficult-to-separate impurities (such as butylbenzene and sec-butylbenzene) in the α-methylstyrene product. The purity of the α-methylstyrene product finally obtained can reach more than 99.9wt%, and ethylbenzene, isopropylbenzene and phenol products are obtained at the same time, which fully promotes the further research on the resource utilization of phenol-ketone tar and the improvement of the economic efficiency of the phenol-ketone device.

[0108] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for extracting α-methylstyrene from phenol-ketone tar cracking products, characterized in that: The method comprises pretreatment, catalytic cracking, dehydration treatment, ethylbenzene distillation, isopropylbenzene distillation and azeotropic distillation performed in sequence, and the azeotropic light component obtained by the azeotropic distillation is subjected to α-methylstyrene distillation, and the heavy component is subjected to phenol distillation; The pretreatment is used to separate phenol and acetophenone in phenol-ketone tar; water is added during the azeotropic distillation process to form an azeotropic light component containing α-methylstyrene.

2. The method according to claim 1, characterized in that: The phenol-ketone tar is a heavy component tar produced as a by-product in the process of producing phenol-acetone by the isopropylbenzene process, and the specific components include: 5-7wt% of phenol, 2-4wt% of α,α-dimethylbenzyl alcohol, 1-2wt% of β-methylphenylethanol, 18-25wt% of acetophenone, 8-9wt% of α-methylstyrene dimer, 3-4.5wt% of 2-cumylphenol, 19.5-22.5wt% of 4-cumylphenol, and 26-40wt% of other inevitable components.

3. The method according to claim 1 or 2, characterized in that: The reaction temperature of the catalytic cracking is 250-350°C, the absolute pressure is 60-150kPa, and the reaction time is 5-20h; Preferably, the temperature of the dehydration treatment is 50-115° C., the absolute pressure is 10-90 kPa, and the water content of the obtained product is ≤0.5 wt %.

4. The method according to any one of claims 1 to 3, characterized in that: The temperature of the ethylbenzene distillation is 70-110° C., the absolute pressure is 5-40 kPa, and the purity of the obtained ethylbenzene product is ≥99.5wt%; Preferably, the temperature of the cumene distillation is 80-120° C., the absolute pressure is 1-30 kPa, and the purity of the obtained cumene product is ≥99.8wt%.

5. The method according to any one of claims 1 to 4, characterized in that: The temperature of the azeotropic distillation is 55-125° C., the absolute pressure is 20-100 kPa, and the mass ratio of water to material is (0.5-5):1; Preferably, the temperature of the α-methylstyrene distillation is 95-105° C., the absolute pressure is 5-40 kPa, and the purity of the obtained α-methylstyrene product is ≥99.9wt%; Preferably, the temperature of the phenol distillation is 110-130° C., the absolute pressure is 1-30 kPa, and the purity of the obtained phenol product is ≥99.8wt%.

6. A device system used in the method according to any one of claims 1 to 5, characterized in that: The device system comprises a cracking product tank, a dehydration tower, an ethylbenzene distillation tower, an isopropylbenzene distillation tower and an azeotropic distillation tower which are connected in sequence, and the top of the azeotropic distillation tower is connected to an alpha-methylstyrene distillation tower, and the bottom of the tower is connected to a phenol distillation tower.

7. The device system according to claim 6, characterized in that: The number of theoretical plates of the dehydration tower is 20-60, a separator tank is arranged on the top of the tower, and an interface meter is arranged in the separator tank.

8. The device system according to claim 6 or 7, characterized in that: The number of theoretical plates of the ethylbenzene distillation tower is 40-70; Preferably, the cumene distillation tower has 40-70 theoretical plates.

9. The device system according to any one of claims 6 to 8, characterized in that: The number of theoretical plates of the azeotropic distillation tower is 50-100, a separatory tank is arranged on the top of the tower, and an interface meter is arranged in the separatory tank.

10. The device system according to any one of claims 6 to 9, characterized in that: The α-methylstyrene distillation tower has a theoretical plate number of 30-70; Preferably, the phenol distillation tower has 20-50 theoretical plates.

Images