Method for recovering X oil

Abstract

The invention relates to a recovery method of X oil. The recovery method comprises the following steps: providing a by-product X oil generated by dehydrogenation preparation of cyclohexanone by taking cyclohexanol as a raw material; carrying out reduced pressure distillation on the X oil to respectively obtain a distillation distillate and a distillation still liquid; the pressure of reduced pressure distillation is-0.095 MPa to-0.1 MPa, the temperature of the tower top is 80-110 DEG C, and the temperature of the tower kettle is 115-190 DEG C; carrying out a dehydration reaction on the distillation still liquid under the action of a metal halide Lewis acid catalyst to obtain a dehydration reaction liquid; carrying out cracking reaction on the dehydration reaction solution under the action of an oxide type solid acid catalyst to obtain a cracking reaction solution; and carrying out solid-liquid separation on the cracking reaction liquid, taking a liquid phase, carrying out first rectification treatment, and collecting cyclohexene at the tower top. The recycling method can effectively improve the resource utilization rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the recycling technical field, in particular to a recovery method of X oil. BACKGROUND

[0002] The industrial production process of caprolactam benzene method mainly includes cyclohexene oxidation method, cyclohexene hydration method and cyclohexene esterification method, and the above processes all contain the key process of preparing cyclohexanone by dehydrogenation of cyclohexanol. In the dehydrogenation reaction process of cyclohexanol, due to the limitation of reaction mechanism, the conversion rate of cyclohexanol is only about 50%, and a large amount of unreacted cyclohexanol needs to be recycled after refining; meanwhile, there are also side reactions such as excessive dehydrogenation of cyclohexanol to generate phenol, dehydration of cyclohexanol to generate cyclohexene, and polymerization of cyclohexanone to generate polyketone in the reaction process.

[0003] In order to purify the target product cyclohexanone and recycle the unreacted cyclohexanol, the dehydrogenation reaction liquid needs to be sequentially treated by four processes of drying, light removal, ketone removal, and alcohol removal. After the above processes, a large amount of by-product X oil will be produced. X oil is complex in composition and low in content of valuable components, and it is difficult to separate and utilize single components by chemical separation. At present, the main treatment method of X oil is fuel oil incineration, which not only wastes the available resources, but also does not meet the development concept of green environmental protection.

[0004] Therefore, it is necessary to improve the traditional technology. SUMMARY

[0005] Based on this, the present application provides a recovery method of X oil with high resource utilization rate.

[0006] The technical scheme for solving the above technical problems of the present application is as follows.

[0007] The first aspect of the present application provides a recovery method of X oil, comprising the following steps:

[0008] A by-product X oil produced in the preparation of cyclohexanone by dehydrogenation of cyclohexanol is provided; the X oil contains, by mass percentage, 0-25% of cyclohexanol, 0-2% of cyclohexanone, 15%-25% of cyclohexyl acetate, 10%-15% of phenol, 10%-20% of 2-cyclohexyl cyclohexanone, 10%-30% of 2-cyclohexyl cyclohexanol, 0-2% of 1-cyclohexyl cyclohexene, 0-1% of cyclohexene cyclohexanol, 0-1% of cyclohexene cyclohexanone, and 0-5% of 2-cyclohexyl cyclohexane-1-ketone;

[0009] The X oil is subjected to vacuum distillation to obtain distillation effluent and distillation still liquid, respectively; the pressure of the vacuum distillation is-0.095 MPa to-0.1 MPa, the top temperature is 80℃ to 110℃, and the bottom temperature is 115℃ to 190℃;

[0010] The distillation kettle liquid is subjected to a dehydration reaction under the action of a metal halide Lewis acid catalyst to obtain a dehydration reaction liquid;

[0011] The dehydration reaction liquid is subjected to a cracking reaction under the action of an oxide type solid acid catalyst to obtain a cracking reaction liquid;

[0012] The cracking reaction liquid is subjected to solid-liquid separation, and the liquid phase is subjected to first rectification treatment, and cyclohexene is collected at the top of the column.

[0013] In some embodiments, the X oil recovery method satisfies at least one of the following characteristics:

[0014] (1) The oxide type solid acid catalyst comprises at least one of aluminum oxide and aluminum silicate;

[0015] (2) The mass of the oxide type solid acid catalyst is 2wt% to 5wt% of the mass of the dehydration reaction liquid;

[0016] (3) The cracking reaction has a pressure of 0.8MPa to 2MPa, a temperature of 300°C to 400°C, and a time of 8h to 16h.

[0017] In some embodiments, the X oil recovery method satisfies at least one of the following characteristics:

[0018] (1) The metal halide Lewis acid catalyst comprises at least one of aluminum chloride and zinc chloride;

[0019] (2) The mass of the metal halide Lewis acid catalyst is 0.5wt% to 2wt% of the mass of the dehydration reaction liquid;

[0020] (3) The dehydration reaction has a pressure of 1.5MPa to 3MPa, a temperature of 180°C to 250°C, and a time of 8h to 12h.

[0021] In some embodiments, the X oil recovery method has a first rectification treatment pressure of 0.09MPa to 0.11MPa, a column top temperature of 80°C to 83°C, a column bottom temperature of 85°C to 95°C, and a reflux ratio of 3 to 4.

[0022] In some embodiments, the X oil recovery method further comprises, before the cracking reaction, subjecting the dehydration reaction liquid to solid-liquid separation, and taking the liquid phase to perform the cracking reaction.

[0023] In some embodiments, the X oil recovery method further comprises the following steps:

[0024] The distillation distillate and C2-C4 alcohol are subjected to an ester exchange reaction in an ester exchange reaction column to obtain a first column top liquid and a first column bottom liquid respectively; the ester exchange reaction is carried out at a pressure of 0.01 MPa to 0.7 MPa and a temperature of 80°C to 125°C;

[0025] The first column top liquid is subjected to a second rectification treatment, and acetic acid ester is collected at the column bottom;

[0026] The first column bottom liquid is subjected to a third rectification treatment, and cyclohexanol is collected at the column side line.

[0027] In some embodiments of the X oil recovery method, the ester exchange reaction satisfies at least one of the following characteristics:

[0028] (1) The molar ratio of the C2-C4 alcohol to the cyclohexyl acetate in the distillation distillate is 3-10:1;

[0029] (2) The ester exchange reaction is carried out in the presence of an ethanol alkali metal catalyst, and the ethanol alkali metal catalyst includes at least one of sodium ethoxide and potassium ethoxide;

[0030] (3) The reflux ratio of the ester exchange reaction is 1-10;

[0031] (4) The time of the ester exchange reaction is 0.5h-2h.

[0032] In some embodiments of the X oil recovery method, the absolute pressure of the second rectification treatment is 0.3 MPa-1 MPa, and the reflux ratio is 2-6.

[0033] In some embodiments of the X oil recovery method, the vacuum degree of the third rectification treatment is 0 MPa-0.1 MPa, the column top temperature is 80°C-85°C, the column bottom temperature is 80°C-120°C, and the reflux ratio is 3-5.

[0034] In some embodiments of the X oil recovery method, before the first column bottom liquid is subjected to the third rectification treatment, the first column bottom liquid is subjected to carbonation treatment with water and carbon dioxide, filtration, and the liquid phase is subjected to the third rectification treatment;

[0035] The carbonation treatment satisfies at least one of the following characteristics:

[0036] (1) The mass ratio of the first column bottom liquid to water is 30-50:1;

[0037] (2) The mass of the first column bottom liquid to the volume of carbon dioxide is 1t:3Nm 3 -8Nm 3 ;

[0038] (3) The pressure of the carbonation treatment is 0.09 MPa to 0.11 MPa;

[0039] (4) The temperature of the carbonation treatment is 60℃~90℃.

[0040] The method for recovering X oil in this application involves subjecting X oil, a byproduct of the dehydrogenation preparation of cyclohexanone from cyclohexanol, to vacuum distillation. The pressure, top temperature, and bottom temperature of the vacuum distillation are controlled. Cyclohexanol, cyclohexanone, cyclohexyl acetate, and phenol in the X oil are distilled off to form a distillate, while the remaining components remain in the distillate. The distillate is then dehydrated using a metal halide Lewis acid catalyst, resulting in the dehydration of 2-cyclohexylcyclohexanol to form 1-cyclohexylcyclohexene. The dehydration reaction is then... The liquid undergoes a cracking reaction, where the original 1-cyclohexylcyclohexene in X oil and the 1-cyclohexylcyclohexene formed by the dehydration of 2-cyclohexylcyclohexanol are cracked into cyclohexene. The cracking reaction is controlled under the action of an oxide-type solid acid catalyst, which can effectively improve the conversion rate of 1-cyclohexylcyclohexene and the selectivity of cyclohexene. The cracking reaction liquid containing cyclohexene is then subjected to solid-liquid separation to remove the oxide-type solid acid catalyst, followed by a first distillation treatment to obtain cyclohexene with high purity and high yield. Detailed Implementation

[0041] The present application will be further described in detail below with reference to the embodiments and examples. It should be understood that these embodiments and examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the disclosure of the present application more thorough and comprehensive.

[0042] It should also be understood that this application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various alterations or modifications without departing from the spirit of this application, and the resulting equivalent forms also fall within the protection scope of this application. For example, features described or illustrated as part of one embodiment can be combined in a suitable manner in another embodiment to produce new embodiments. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of this application; it should be understood that this application can be implemented without one or more of these details.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for descriptive purposes only and is not intended to be limiting of the application.

[0044] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0045] In this application, the terms "multiple", "various", "multiple times", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0046] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0047] In this document, the term "suitable" as used in "suitable combination", "suitable method", "any suitable method", etc., refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0048] In this document, terms such as "preferred," "better," "more suitable," and "ideal" are merely descriptions of more effective implementation methods or embodiments, and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0049] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0050] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0051] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0052] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0053] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0054] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0055] In this application, the terms "room temperature" or "normal temperature" generally refer to 4℃ to 35℃, for example, 20℃ ± 5℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10℃ to 30℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20℃ to 30℃.

[0056] In this application, if the unit of a data range is only followed by the right endpoint, it indicates that the units of the left and right endpoints are the same. For example, 3~5 h means that the units of the left endpoint "3" and the right endpoint "5" are both h (hours).

[0057] The mass or weight of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship of mass or weight between the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass or weight mentioned in the embodiments of this application can be units known in the chemical industry, such as μg, mg, g, and kg.

[0058] Current methods for processing X oil have the following problems: the content of each individual component in X oil is relatively low, making recovery through distillation of low value; X oil processing equipment is numerous, resulting in a long process flow; the cracking temperature is high, leading to significant energy consumption; the cracked components are complex, with low content of effective components, producing both gaseous and liquid products, and the purity is poor, resulting in low practical utilization value. Even if X oil is chemically treated and physically separated for use as a mineral processing agent, buffer, leather tanning oil, or drying oil, the fundamental problem of reducing and recycling byproducts in chemical production processes remains unresolved.

[0059] One embodiment of this application provides a method for recovering X oil, comprising the following steps:

[0060] Step S100: Provide X oil, a byproduct generated from the dehydrogenation of cyclohexanone from cyclohexanol; by mass percentage, X oil comprises: 0-25% cyclohexanol, 0-2% cyclohexanone, 15%-25% cyclohexyl acetate, 10%-15% phenol, 10%-20% 2-cyclohexylcyclohexanone, 10%-30% 2-cyclohexylcyclohexanol, 0-2% 1-cyclohexylcyclohexene, 0-1% cyclohexenylcyclohexanol, 0-1% cyclohexenylcyclohexanone, and 0-5% 2-cyclohexylene-1-cyclohexane.

[0061] In some examples, the method for preparing cyclohexanone from cyclohexanol by dehydrogenation includes at least one of cyclohexene oxidation, cyclohexene hydration, and cyclohexene esterification. It is understood that oil X can be a mixture of byproducts from various cyclohexanone preparation methods, including cyclohexene oxidation, cyclohexene hydration, and cyclohexene esterification.

[0062] In some of these examples, by mass percentage, oil X comprises: 1%–25% cyclohexanol, 0.1%–2% cyclohexanone, 15%–25% cyclohexyl acetate, 10%–15% phenol, 10%–20% 2-cyclohexylcyclohexanone, 10%–30% 2-cyclohexylcyclohexanol, 0.1%–2% 1-cyclohexylcyclohexene, 0.1%–1% cyclohexenylcyclohexanol, 0.1%–1% cyclohexenylcyclohexanone, and 1%–5% 2-cyclohexylenecyclohexane-1-one.

[0063] It is understood that, by mass percentage, X oil contains, but is not limited to, cyclohexanol at concentrations of 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, and 25%; cyclohexanone at concentrations of 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, and 2%; cyclohexyl acetate at concentrations of 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, and 25%; phenol at concentrations of 10%, 11%, 12%, 13%, 14%, and 15%; and 2-cyclohexylcyclohexanone at concentrations of 10% and 12%. 15%, 18%, 20%; 2-Cyclohexylcyclohexanol, including but not limited to 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%; 1-Cyclohexylcyclohexene, including but not limited to 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%; Cyclohexenylcyclohexanol, including but not limited to 0.1%, 0.2%, 0.5%, 0.8%, 1%; Cyclohexenylcyclohexanone, including but not limited to 0.1%, 0.2%, 0.5%, 0.8%, 1%; 2-Cyclohexylenecyclohexane-1-one, including but not limited to 1%, 2%, 3%, 4%, 5%.

[0064] Step S200: The X oil is subjected to vacuum distillation to obtain distillate and distillate liquid respectively; the pressure of vacuum distillation is -0.095MPa to -0.1MPa, the top temperature of the column is 80℃ to 110℃, and the bottom temperature of the column is 115℃ to 190℃.

[0065] X oil, a byproduct of the dehydrogenation of cyclohexanone from cyclohexanol, is subjected to vacuum distillation. The pressure, top temperature, and bottom temperature of the vacuum distillation are controlled. Cyclohexanol, cyclohexanone, cyclohexyl acetate, and phenol in X oil are distilled off to form distillate, while the remaining components remain in the distillate.

[0066] It can be understood that -0.095MPa to -0.1MPa is a negative pressure. Further, the pressure of vacuum distillation includes, but is not limited to, -0.095MPa, -0.098MPa, and -0.1MPa; the column top temperature includes, but is not limited to, 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, 92℃, 94℃, 96℃, 98℃, 100℃, 102℃, 104℃, 106℃, 108℃, and 110℃; and the column bottom temperature includes, but is not limited to, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, and 190℃. In some examples, any two of these point values ​​can be used as endpoints within a range, and the same applies below.

[0067] Step S300: The distillate obtained in step S200 is subjected to a dehydration reaction under the action of a metal halide Lewis acid catalyst to obtain a dehydrated reaction solution.

[0068] The distillate is dehydrated in the presence of a metal halide Lewis acid catalyst, and the 2-cyclohexylcyclohexanol in the distillate is dehydrated to form 1-cyclohexylcyclohexene. The dehydration reaction is more thorough, and a large amount of 1-cyclohexylcyclohexene intermediate that is prone to cracking can be obtained.

[0069] In some of these examples, in step S300, the metal halide Lewis acid catalyst comprises at least one of aluminum chloride and zinc chloride. Optionally, the metal halide Lewis acid catalyst comprises at least one of anhydrous aluminum chloride and anhydrous zinc chloride.

[0070] In some examples, in step S300, the mass of the metal halide Lewis acid catalyst is 0.5 wt% to 2 wt% of the mass of the dehydration reaction solution. It is understood that the mass ratio of the metal halide Lewis acid catalyst to the mass of the dehydration reaction solution includes, but is not limited to, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, and 2 wt%.

[0071] In some examples, in step S300, the dehydration reaction is carried out at a pressure of 1.5 MPa to 3 MPa, a temperature of 180°C to 250°C, and a time of 8 h to 12 h. It is understood that the dehydration reaction pressure includes, but is not limited to, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, 2.9 MPa, and 3 MPa; the temperature includes, but is not limited to, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, and 250°C; and the time includes, but is not limited to, 8 h, 9 h, 10 h, 11 h, and 12 h.

[0072] It is understood that the dehydration reaction in step S300 is carried out in a high-pressure reactor, and nitrogen gas is introduced to pressurize the reactor to the pressure required for the dehydration reaction described above.

[0073] In some examples, before step S400, the process includes: performing solid-liquid separation on the dehydrated reaction liquid obtained in step S300, and taking the liquid phase for pyrolysis reaction.

[0074] It is understandable that the metal halide Lewis acid catalyst is removed by filtration and separation, and the resulting clear liquid phase is then transferred to a high-pressure pyrolysis reactor for pyrolysis reaction.

[0075] Step S400: The dehydrated reaction solution is subjected to a pyrolysis reaction under the action of an oxide-type solid acid catalyst to obtain a pyrolysis reaction solution.

[0076] The dehydration reaction solution is subjected to a pyrolysis reaction. The original 1-cyclohexylcyclohexene in X oil and the 1-cyclohexylcyclohexene formed from the dehydration of 2-cyclohexylcyclohexanol are pyrolyzed into cyclohexene. The pyrolysis reaction is controlled under the action of an oxide-type solid acid catalyst, which effectively improves the conversion rate of 1-cyclohexylcyclohexene and also significantly enhances the selectivity of cyclohexene. This method overcomes the difficulties and low degree of pyrolysis that occur with direct pyrolysis of X oil, improving the pyrolysis efficiency and allowing for the extraction of more cyclohexene.

[0077] In some of these examples, in step S400, the oxide-type solid acid catalyst includes at least one of alumina and aluminum silicate.

[0078] In some examples, in step S400, the mass of the oxide-type solid acid catalyst is 2wt% to 5wt% of the mass of the dehydration reaction solution. It is understood that the mass ratio of the oxide-type solid acid catalyst to the mass of the dehydration reaction solution includes, but is not limited to, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, and 5wt%.

[0079] In some examples, in step S400, the pressure of the pyrolysis reaction is 0.8 MPa to 2 MPa, the temperature is 300℃ to 400℃, and the time is 8h to 16h. It can be understood that the pressure of the pyrolysis reaction includes, but is not limited to, 0.8 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, and 2 MPa; the temperature includes, but is not limited to, 00℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, and 400℃; and the time includes, but is not limited to, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, and 16h.

[0080] In some of these examples, step S400, the pyrolysis reaction, is carried out in a high-pressure pyrolysis reactor, with nitrogen gas introduced to pressurize the reactor to the pressure required for the aforementioned pyrolysis reaction.

[0081] Step S500: The pyrolysis reaction liquid is subjected to solid-liquid separation, the liquid phase is taken for first distillation treatment, and cyclohexene is collected at the top of the column.

[0082] By performing solid-liquid separation on the pyrolysis reaction liquid containing cyclohexene to remove the oxide-type solid acid catalyst, and then performing a first distillation treatment, high-purity cyclohexene can be obtained. At the same time, through the coordination of each step and parameter in steps S200 to S500, the yield of cyclohexene is high.

[0083] In some examples, in step S500, the pressure of the first distillation process is 0.09 MPa to 0.11 MPa, the top temperature is 80°C to 83°C, the bottom temperature is 85°C to 95°C, and the reflux ratio is 3 to 4. It can be understood that the pressure of the first distillation process includes, but is not limited to, 0.09 MPa, 0.1 MPa, and 0.11 MPa; the top temperature includes, but is not limited to, 80°C, 81°C, 82°C, and 83°C; the bottom temperature includes, but is not limited to, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, and 95°C; and the reflux ratio includes, but is not limited to, 3, 3.5, and 4.

[0084] In some of these examples, the recovery method for oil X further includes the following steps:

[0085] Step S600: The distillate obtained in step S200 and the C2~C4 alcohol are subjected to transesterification reaction in a transesterification reaction tower to obtain the first tower top liquid and the first tower bottom liquid, respectively; the pressure of the transesterification reaction is 0.01Mpa~0.7Mpa, and the temperature is 80℃~125℃.

[0086] It is understandable that in step S600, cyclohexyl acetate and C2-C4 alcohols in oil undergo a transesterification reaction in the transesterification tower to produce cyclohexanol and acetate, thereby increasing the cyclohexanol content and enhancing its recovery value. Simultaneously, the acetate produced can also be recovered, further increasing its utilization value. By controlling the pressure and temperature of the transesterification reaction, the first overhead liquid of the transesterification tower mainly consists of C2-C4 alcohols and the product acetate, while the first bottom liquid mainly contains cyclohexanol, cyclohexanone, phenol, and C2-C4 alcohols.

[0087] It is understood that the pressure of the transesterification reaction includes, but is not limited to, 0.01 MPa, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, and 0.7 MPa, and the temperature includes, but is not limited to, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, and 125℃.

[0088] In some examples, in step S600, the molar ratio of C2-C4 alcohol to cyclohexyl acetate in the distillate is 3-10:1. It is understood that the molar ratio of C2-C4 alcohol to cyclohexyl acetate in the distillate includes, but is not limited to, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, and 10:1.

[0089] In some examples, in step S600, the transesterification reaction is carried out in the presence of an alkali metal catalyst for ethanol. It is understood that the first bottom liquid of the transesterification column also contains the alkali metal catalyst for ethanol. Optionally, the alkali metal catalyst for ethanol includes at least one of sodium ethoxide and potassium ethoxide. Optionally, the amount of alkali metal catalyst added is 0.05% to 1% of the mass of the distillate.

[0090] In some examples, the reflux ratio for the transesterification reaction in step S600 is 1 to 10. It is understood that the reflux ratio for the transesterification reaction includes, but is not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0091] In some examples, the transesterification reaction time in step S600 is 0.5 h to 2 h. It is understood that the transesterification reaction time includes, but is not limited to, 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h, and 2 h.

[0092] Step S700: The liquid from the top of the first column is subjected to a second distillation process, and acetate is collected in the bottom of the column.

[0093] In some examples, in step S700, the absolute pressure of the second distillation process is 0.3 MPa to 1 MPa, and the reflux ratio is 2 to 6. It is understood that the absolute pressure of the second distillation process includes, but is not limited to, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, and 1 MPa, and the reflux ratio includes, but is not limited to, 2, 3, 4, 5, and 6.

[0094] It is understandable that the first column overhead liquid mainly consists of C2~C4 alcohols and the product acetate. By subjecting the first column overhead liquid to a second distillation process and controlling the absolute pressure and reflux ratio of the second distillation process, acetate can be collected in the column bottom, and the mass content of acetate is relatively high (acetic acid content ≥99%, water content ≤0.1%).

[0095] Step S800: The liquid in the bottom of the first column is subjected to a third distillation process, and cyclohexanol is collected from the side stream of the column.

[0096] In some examples, in step S800, the vacuum degree of the third distillation process is 0 MPa to 0.1 MPa, the top temperature is 80°C to 85°C, the bottom temperature is 80°C to 120°C, and the reflux ratio is 3 to 5. It can be understood that the vacuum degree of the third distillation process includes, but is not limited to, 0 MPa, 0.01 MPa, 0.02 MPa, 0.03 MPa, 0.04 MPa, 0.05 MPa, 0.06 MPa, 0.07 MPa, 0.08 MPa, 0.09 MPa, and 0.1 MPa; the top temperature includes, but is not limited to, 80°C, 81°C, 82°C, 83°C, 84°C, and 85°C; the bottom temperature includes, but is not limited to, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, and 120°C; and the reflux ratio includes, but is not limited to, 3, 4, and 5.

[0097] In some examples, step S800, before the first column bottom liquid is subjected to a third distillation treatment, includes: carbonating the first column bottom liquid with water and carbon dioxide, filtering, and taking the liquid phase for a third distillation treatment.

[0098] It is understood that in step S600, when the transesterification reaction is carried out under the action of the alkali metal catalyst of ethanol, the bottom liquid of the first column of the transesterification reaction tower also contains the alkali metal catalyst of ethanol. At this time, the bottom liquid of the first column mainly contains cyclohexanol, cyclohexanone, phenol, and C2-C4 alcohols. The bottom liquid of the first column is sent to a distillation column, and the C2-C4 alcohols at the top of the distillation column are distilled back to the transesterification reaction tower in gaseous form. The bottom product of the distillation column includes C2-C4 alcohols, cyclohexanol, cyclohexanone, phenol, and the alkali metal catalyst of ethanol, wherein the mass content of cyclohexanol + cyclohexanone + phenol in the mixture is >95%, and the mass content of C2-C4 alcohols is <5%. In step S800, the bottom liquid of the first column is carbonated with water and carbon dioxide. The alkali metal catalyst of ethanol in the bottom liquid of the first column reacts with carbon dioxide to form solid alkali metal carbonates, which are removed by filtration. At this time, the liquid phase mainly consists of cyclohexanol, cyclohexanone, and phenol.

[0099] In some examples, in step S800, the mass ratio of the first column bottom liquid to water is 30~50:1. It can be understood that the mass ratio of the first column bottom liquid to water includes, but is not limited to, 30:1, 32:1, 34:1, 36:1, 38:1, 40:1, 42:1, 44:1, 46:1, 48:1, and 50:1.

[0100] In some of these examples, in step S800, the mass ratio of the first column bottom liquid to the volume ratio of carbon dioxide is 1t:3Nm. 3 ~8Nm 3 It is understood that the mass ratio of the liquid in the first column bottom to the volume ratio of carbon dioxide is, but is not limited to, 1t:3Nm. 3 1t:4Nm 31t:5Nm 3 1t:6Nm 3 1t:7Nm 3 1t:8Nm 3 .

[0101] In some examples, the carbonation treatment pressure in step S800 is 0.09 MPa to 0.11 MPa. It is understood that the carbonation treatment pressure includes, but is not limited to, 0.09 MPa, 0.1 MPa, and 0.11 MPa. Optionally, the carbonation treatment is carried out at atmospheric pressure.

[0102] In some examples, the carbonation temperature in step S800 is 60°C to 90°C. It is understood that the carbonation temperature includes, but is not limited to, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, and 90°C.

[0103] In some examples, in step S800, the carbonation process is carried out under stirring conditions. Optionally, the stirring speed is 60 r / min to 125 r / min.

[0104] In some of these examples, in step S800, carbonation is performed in a hydrolysis carbonization tower.

[0105] In some of these examples, in step S800, the filtration accuracy is 3μm~20μm, the filtration temperature is 50℃~70℃, and the filtration pressure is 0.2Mpa~0.6Mpa.

[0106] It is understandable that the top product of the third distillation process includes a mixture of water, alcohol and cyclohexanol, while the bottom product can be returned to the hydrolysis carbonization tower for reprocessing.

[0107] The X oil recovery method provided in this application comprehensively utilizes X oil waste liquid, has a simple process, and requires less equipment. The cyclohexanol content of the light component of X oil is increased, which improves its recycling value. At the same time, it also produces acetate as a by-product. Furthermore, the heavy components of X oil have fewer components after dehydration and subsequent cracking, resulting in higher product value and higher overall resource utilization. Compared with traditional high-temperature cracking reactions, it has lower energy consumption, fewer components, no gaseous products, is easy to recover, energy-saving and environmentally friendly, and has lower costs.

[0108] The present application will be described in further detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0109] The X oil used in the following examples and comparative examples is a mixture of oxidized heavy oil, hydrated heavy oil and esterified heavy oil produced by different production processes. By mass percentage, it includes 11% cyclohexanol, 2% cyclohexanone, 20% cyclohexyl acetate, 10% phenol, 20% 2-cyclohexylcyclohexanone, 30% 2-cyclohexylcyclohexanol, 2% 1-cyclohexylcyclohexene, 1% cyclohexenylcyclohexanol, 1% cyclohexenylcyclohexanone, and 3% 2-cyclohexylene-1-cyclohexane.

[0110] Example 1:

[0111] Step 1: X oil is first separated from its useful components, cyclohexanol, cyclohexanone, cyclohexyl acetate and phenol, by vacuum distillation. The negative pressure is controlled at -0.10 MPa, the top temperature is 80℃ and the bottom temperature is 115℃. The X oil distillate is then subjected to transesterification, and the remaining X oil distillate is sent to a high-pressure reactor for dehydration.

[0112] Step 2: The X oil distillate, ethanol, and sodium ethoxide catalyst obtained above are pumped into a transesterification reaction tower for transesterification. The molar ratio of ethanol to cyclohexyl acetate in the X oil distillate is controlled at 4:1. The amount of sodium ethoxide catalyst added is 0.9% of the mass of the raw material (X oil distillate). The reaction temperature in the transesterification reaction tower is 80℃~84℃, the reaction pressure is 0.01 MPa, the reflux ratio is 3, and the reaction residence time is 0.5 h. The mass content of ethyl acetate in the mixture at the top of the transesterification reaction tower is 61.12%, the mass content of ethanol is 38.19%, and the mass content of cyclohexanol is 0.69%. The bottom mixture of the transesterification reaction column contained 37.63% cyclohexanol, 3.23% cyclohexanone, 15.42% phenol, 43.23% ethanol, and 0.49% ethyl acetate. The overhead product was directly pumped into the first distillation column for separation, with an absolute pressure of 1.0 MPa and a reflux ratio of 4. After pressurized distillation, ethanol and ethyl acetate were refluxed back to the first distillation column. The bottom product was ethyl acetate with a purity of 99.0% and a water content of ≤0.10%. The bottom liquid of the transesterification reaction column mainly contained cyclohexanol, cyclohexanone, phenol, and ethanol. This bottom liquid was pumped to a distillation column. The overhead product of the distillation column, ethanol, was distilled back to the transesterification reaction column in vapor form. The bottom product of the distillation column included ethanol, cyclohexanol, cyclohexanone, phenol, and catalyst. The organic mixture contained >95% cyclohexanol + cyclohexanone + phenol and <5% ethanol. The bottom product of the distillation column enters the hydrolysis carbonization tower for carbonation treatment. Each feed is 40t, with 1t of water and 6Nm³ of carbon dioxide introduced. 3The stirring speed was 60 r / min to 125 r / min, the reaction pressure was atmospheric pressure, and the reaction temperature was 70℃. After the carbonation reaction was completed, the mixture was filtered with a filtration precision of 3 μm to 20 μm, a filtration temperature of 60℃, and a filtration pressure of 0.4 MPa, yielding a high-content crude cyclohexanol, cyclohexanone, and phenol mixture. This mixture was then pumped into a second distillation column for vacuum distillation, with the bottom temperature controlled at 80℃ to 120℃, the top temperature of the second distillation column at 80℃ to 85℃, the vacuum degree of the second distillation column at 0.1 MPa, and the reflux ratio in the second distillation column at 3. The top product of the second distillation column included a mixture of water, alcohol, and cyclohexanol. A side stream of 99.5% cyclohexanol was collected for recovery. The bottom product of the second distillation column was returned to the hydrolysis carbonization column for reprocessing.

[0113] Step 3: The distillate obtained above is pumped into a high-pressure reactor. First, 0.5 wt% of anhydrous aluminum chloride catalyst is added to the reactor liquid. The high-pressure reactor is sealed, and stirring is started. After mixing evenly, nitrogen gas is introduced to pressurize to 1.5 MPa, and the temperature is raised to the dehydration reaction temperature of 180℃. The reaction is started and timed for 8 hours. After the reaction, the conversion rate of 2-cyclohexylcyclohexanol reaches 45.6%, and the selectivity of 1-cyclohexylcyclohexene reaches 96.9%. The dehydrated reaction liquid from the high-pressure reactor is filtered to remove the aluminum chloride catalyst powder, and the resulting clear liquid is transferred to a high-pressure cracking reactor.

[0114] Step 4: The filtered and clarified dehydrated reaction solution was pumped into a high-pressure pyrolysis reactor, and 2 wt% of activated alumina catalyst was added. The high-pressure reactor was sealed, and stirring was started. After mixing evenly, nitrogen gas was introduced to pressurize to 0.8 MPa, and the temperature was raised to the pyrolysis reaction temperature of 300℃. The reaction was started and timed for 8 hours. After the reaction was completed, the conversion rate of 1-cyclohexylcyclohexene reached 90.4%, and the selectivity of cyclohexene reached 95.7%.

[0115] Step 5: After filtering the catalyst from the reaction solution obtained from the above cracking, crude cyclohexene is obtained and pumped into the third distillation column for atmospheric distillation of cyclohexene. The top temperature is controlled at 80~83℃, the bottom temperature at 85~95℃, and the reflux ratio at 3~4. Finally, cyclohexene with a mass content of 99.5% and a mass yield of 95.8% is obtained.

[0116] Example 2:

[0117] Step 1: X oil is first separated from its useful components, cyclohexanol, cyclohexanone, cyclohexyl acetate and phenol, by vacuum distillation. The negative pressure is controlled at -0.095 MPa, the top temperature is 109℃ and the bottom temperature is 190℃. The X oil distillate is then subjected to transesterification, and the remaining X oil distillate is sent to a high-pressure reactor for dehydration.

[0118] Step 2: The X oil distillate, propanol, and catalyst obtained above are pumped into a transesterification reactor for transesterification. The molar ratio of propanol to cyclohexyl acetate is controlled at 4:1, the amount of sodium ethoxide catalyst added is 0.8% of the raw material mass, the reaction temperature of the transesterification reactor is 103℃~121℃, the reaction pressure is 0.01 MPa, the reflux ratio is 3, and the reaction residence time is 0.5 h. The mass content of propyl acetate in the mixture at the top of the transesterification reactor is 48.78%, the mass content of propanol is 48.85%, and the mass content of cyclohexyl alcohol is 2.37%. The mixture in the bottom of the transesterification tower contains 33.67% cyclohexanol, 3.95% cyclohexanone, 12.04% phenol, 50.12% propanol, and 0.22% propyl acetate. The overhead product is directly pumped into the first distillation column for separation, with an absolute pressure of 1.0 MPa and a reflux ratio of 4. After pressurized distillation, propanol and propyl acetate are refluxed back to the first distillation column. The bottom product is propyl acetate with a content of 99.0% and water ≤0.10%. The bottom liquid of the transesterification reaction tower mainly contains cyclohexanol, cyclohexanone, phenol, and propanol. This bottom liquid is pumped to a distillation column. The overhead product of the distillation column, propanol, is distilled back to the transesterification reaction tower in gaseous form. The bottom product of the distillation column includes propanol, cyclohexanol, cyclohexanone, phenol, and catalyst. The mass content of cyclohexanol + cyclohexanone + phenol in the organic mixture is >95%, and the mass content of propanol is <5%. The bottom product of the distillation column enters the hydrolysis carbonization tower for carbonation treatment. Each feed is 40t, with 1t of water and 6Nm³ of carbon dioxide introduced. 3 The stirring speed was 60 r / min to 125 r / min, the reaction pressure was atmospheric pressure, and the reaction temperature was 70℃. After the carbonation reaction was completed, the mixture was filtered with a filtration precision of 3 μm to 20 μm, a filtration temperature of 60℃, and a filtration pressure of 0.4 MPa, yielding a high-content crude cyclohexanol, cyclohexanone, and phenol mixture. This mixture was then pumped into a second distillation column for vacuum distillation, with the bottom temperature controlled at 80℃ to 120℃, the top temperature of the second distillation column at 80℃ to 85℃, the vacuum degree of the second distillation column at 0.1 MPa, and the reflux ratio in the second distillation column at 3. The top product of the second distillation column included a mixture of water, alcohol, and cyclohexanol. A side stream of 99.5% cyclohexanol was collected for recovery. The bottom product of the second distillation column was returned to the hydrolysis carbonization column for reprocessing.

[0119] Step 3: The distillate obtained above is pumped into a high-pressure reactor. First, 0.8 wt% of anhydrous aluminum chloride catalyst is added to the reactor liquid. The high-pressure reactor is sealed, and stirring is started. After mixing evenly, nitrogen gas is introduced to pressurize to 2.0 MPa, and the temperature is raised to the dehydration reaction temperature of 210℃. The reaction is started and timed for 10 hours. After the reaction, the conversion rate of 2-cyclohexylcyclohexanol reaches 95.3%, and the selectivity of 1-cyclohexylcyclohexene reaches 98.5%. The dehydrated reaction liquid from the high-pressure reactor is filtered to remove the aluminum chloride catalyst powder, and the resulting clear liquid is transferred to a high-pressure cracking reactor.

[0120] Step 4: The filtered and clarified dehydrated reaction solution is pumped into a high-pressure pyrolysis reactor, and 3 wt% of activated alumina catalyst is added. The high-pressure reactor is sealed, and stirring is started. After thorough mixing, nitrogen gas is introduced to pressurize to 1.5 MPa, and the temperature is raised to the pyrolysis reaction temperature of 380℃. The reaction is started and timed for 10 hours. After the reaction is completed, the conversion rate of 1-cyclohexylcyclohexene can reach 98.9%, and the selectivity of cyclohexene can reach 99.2%.

[0121] Step 5: After filtering the catalyst from the reaction solution obtained from the above cracking, crude cyclohexene is obtained and pumped into the third distillation column for atmospheric distillation of cyclohexene. The top temperature is controlled at 80℃~83℃, the bottom temperature at 85℃~95℃, and the reflux ratio at 3~4. Finally, cyclohexene with a mass content of 99.5% and a mass yield of 96.8% is obtained.

[0122] Example 3:

[0123] Step 1: X oil is first separated from its useful components, cyclohexanol, cyclohexanone, cyclohexyl acetate and phenol, by vacuum distillation. The negative pressure is controlled at -0.098 MPa, the top temperature is 93℃ and the bottom temperature is 185℃. The X oil distillate is then subjected to transesterification, and the remaining X oil distillate is sent to a high-pressure reactor for dehydration.

[0124] Step 2: The X oil distillate, ethanol, and catalyst obtained above are pumped into a transesterification reactor for transesterification. The molar ratio of ethanol to cyclohexyl acetate is controlled at 8:1, the amount of sodium ethoxide catalyst added is 0.9% of the raw material mass, the reaction temperature in the transesterification reactor is 80℃~84℃, the reaction pressure is 0.01 MPa, the reflux ratio is 3, and the reaction residence time is 0.5 h. The mass content of ethyl acetate in the mixture at the top of the transesterification reactor is 33.03%, the mass content of ethanol is 66.75%, and the mass content of cyclohexanol is 0.22%. The mixture in the bottom of the transesterification tower contains 18.75% cyclohexanol, 3.28% cyclohexanone, 10.65% phenol, and 67.32% propanol by mass. The overhead product is directly pumped into the first distillation column for separation, with an absolute pressure controlled at 1.0 MPa and a reflux ratio of 4. After pressurized distillation, ethanol and ethyl acetate are obtained from the top of the first distillation column and refluxed back into the first distillation column. The bottom product is ethyl acetate with a content of 99.0% and water ≤0.10%. The bottom liquid of the transesterification reaction column mainly contains cyclohexanol, cyclohexanone, and phenol. This bottom liquid is pumped to a distillation column. The overhead product of the distillation column, ethanol, is distilled back into the transesterification reaction column in gaseous form. The bottom product of the distillation column includes ethanol, cyclohexanol, cyclohexanone, phenol, and catalyst. The mass content of cyclohexanol + cyclohexanone + phenol in the organic mixture is >95%, and the mass content of ethanol is <5%. The bottom product of the distillation column enters the hydrolysis carbonization tower for carbonation treatment. Each feed is 40t, with 1t of water and 6Nm³ of carbon dioxide introduced. 3 The stirring speed was 60 r / min to 125 r / min, the reaction pressure was atmospheric pressure, and the reaction temperature was 70℃. After the carbonation reaction was completed, the mixture was filtered with a filtration precision of 3 μm to 20 μm, a filtration temperature of 60℃, and a filtration pressure of 0.4 MPa, yielding a high-content crude cyclohexanol, cyclohexanone, and phenol mixture. This mixture was then pumped into a second distillation column for vacuum distillation, with the bottom temperature controlled at 80℃ to 120℃, the top temperature of the second distillation column at 80℃ to 85℃, the vacuum degree of the second distillation column at 0.1 MPa, and the reflux ratio in the second distillation column at 3. The top product of the second distillation column included a mixture of water, alcohol, and cyclohexanol. A side stream of 99.5% cyclohexanol was collected for recovery. The bottom product of the second distillation column was returned to the hydrolysis carbonization column for reprocessing.

[0125] Step 3: The distillate obtained above is pumped into a high-pressure reactor. 2.0 wt% of anhydrous aluminum chloride catalyst is added to the reactor liquid. The high-pressure reactor is sealed, and stirring is started. After thorough mixing, nitrogen gas is introduced to pressurize to 3.0 MPa, and the temperature is raised to the dehydration reaction temperature of 250°C. The reaction is started and timed for 12 hours. After the reaction, the conversion rate of 2-cyclohexylcyclohexanol reaches 96.5%, and the selectivity of 1-cyclohexylcyclohexene reaches 94.2%. The dehydrated reaction liquid from the high-pressure reactor is filtered to remove the aluminum chloride catalyst powder, and the resulting clear liquid is transferred to a high-pressure cracking reactor.

[0126] Step 4: The filtered and clarified dehydrated reaction solution was pumped into a high-pressure pyrolysis reactor, and 5 wt% of activated alumina catalyst was added. The high-pressure reactor was sealed, and stirring was started. After mixing evenly, nitrogen gas was introduced to pressurize to 2.0 MPa, and the temperature was raised to the pyrolysis reaction temperature of 400℃. The reaction was started and timed for 16 hours. After the reaction was completed, the conversion rate of 1-cyclohexylcyclohexene reached 99.6%, and the selectivity of cyclohexene reached 91.3%.

[0127] Step 5: After filtering the catalyst from the reaction solution obtained from the above cracking, crude cyclohexene is obtained and pumped into the third distillation column for atmospheric distillation of cyclohexene. The top temperature is controlled at 80℃~83℃, the bottom temperature at 85℃~95℃, and the reflux ratio at 3~4. Finally, cyclohexene with a mass content of 99.5% and a mass yield of 95.1% is obtained.

[0128] Example 4:

[0129] Step 1: X oil is first separated from its useful components, cyclohexanol, cyclohexanone, cyclohexyl acetate and phenol, by vacuum distillation. The negative pressure is controlled at -0.098 MPa, the top temperature is 93℃ and the bottom temperature is 185℃. The X oil distillate is then subjected to transesterification, and the remaining X oil distillate is sent to a high-pressure reactor for dehydration.

[0130] Step 2: The X oil distillate, propanol, and catalyst obtained above are pumped into a transesterification reactor for transesterification. The molar ratio of propanol to cyclohexyl acetate is controlled at 8:1, the amount of sodium ethoxide catalyst added is 0.8% of the raw material mass, the reaction temperature of the transesterification reactor is 103℃~121℃, the reaction pressure is 0.01 MPa, the reflux ratio is 3, and the reaction residence time is 0.5 h. The mass content of propyl acetate in the mixture at the top of the transesterification reactor is 49.17%, the mass content of propanol is 47.85%, and the mass content of cyclohexyl alcohol is 2.98%. The bottom mixture of the transesterification reaction column contained 31.96% cyclohexanol, 3.72% cyclohexanone, 11.52% phenol, 51.28% propanol, and 1.52% propyl acetate. The overhead product was directly pumped into the first distillation column for separation, with an absolute pressure of 1.0 MPa and a reflux ratio of 4. After pressurized distillation, ethanol and ethyl acetate were refluxed back to the first distillation column. The bottom product was ethyl acetate with a purity of 99.0% and a water content of ≤0.10%. The bottom liquid of the transesterification reaction column mainly contained cyclohexanol, cyclohexanone, and phenol. This bottom liquid was pumped to a distillation column. The overhead product of the distillation column, ethanol, was distilled back to the transesterification reaction column in vapor form. The bottom product of the distillation column included ethanol, cyclohexanol, cyclohexanone, phenol, and a catalyst. The organic mixture contained >95% cyclohexanol + cyclohexanone + phenol, and <5% ethanol. The bottom product of the distillation column enters the hydrolysis carbonization tower for carbonation treatment. Each feed is 40t, with 1t of water and 6 Nm³ of carbon dioxide introduced. 3 The stirring speed was 60 r / min to 125 r / min, the reaction pressure was atmospheric pressure, and the reaction temperature was 70℃. After the carbonation reaction was completed, the mixture was filtered with a filtration precision of 3 μm to 20 μm, a filtration temperature of 60℃, and a filtration pressure of 0.4 MPa, yielding a high-content crude cyclohexanol, cyclohexanone, and phenol mixture. This mixture was then pumped into a second distillation column for vacuum distillation, with the bottom temperature controlled at 80℃ to 120℃, the top temperature of the second distillation column at 80℃ to 85℃, the vacuum degree of the second distillation column at 0.1 MPa, and the reflux ratio in the second distillation column at 3. The top product of the second distillation column included a mixture of water, alcohol, and cyclohexanol. A side stream of 99.5% cyclohexanol was collected for recovery. The bottom product of the second distillation column was returned to the hydrolysis carbonization column for reprocessing.

[0131] Step 3: The distillate obtained above is pumped into a high-pressure reactor. First, 0.8 wt% of anhydrous zinc chloride catalyst is added to the reactor liquid. The high-pressure reactor is sealed, and stirring is started. After mixing evenly, nitrogen gas is introduced to pressurize to 2.0 MPa, and the temperature is raised to the dehydration reaction temperature of 210℃. The reaction is started and timed for 10 hours. After the reaction, the conversion rate of 2-cyclohexylcyclohexanol reaches 92.8%, and the selectivity of 1-cyclohexylcyclohexene reaches 97.9%. The dehydrated reaction liquid from the high-pressure reactor is filtered to remove the zinc chloride catalyst powder, and the resulting clear liquid is transferred to a high-pressure cracking reactor.

[0132] Step 4: The filtered and clarified dehydrated reaction solution was pumped into a high-pressure pyrolysis reactor, and 2 wt% of activated alumina catalyst was added. The high-pressure reactor was sealed, and stirring was started. After mixing evenly, nitrogen gas was introduced to pressurize to 2.0 MPa, and the temperature was raised to the pyrolysis reaction temperature of 400℃. The reaction was started and timed for 10 hours. After the reaction was completed, the conversion rate of 1-cyclohexylcyclohexene reached 98.3%, and the selectivity of cyclohexene reached 97.6%.

[0133] Step 5: After filtering the catalyst from the reaction solution obtained from the above cracking, crude cyclohexene is obtained and pumped into the third distillation column for atmospheric distillation of cyclohexene. The top temperature is controlled at 80℃~83℃, the bottom temperature at 85℃~95℃, and the reflux ratio is 3~4. Finally, cyclohexene with a mass content of 99.5% and a mass yield of 95.9% is obtained.

[0134] Example 5:

[0135] This is basically the same as Example 2, except that the transesterification reaction in step two uses potassium ethoxide as a catalyst, as detailed below:

[0136] Step 1: X oil is first separated from its useful components, cyclohexanol, cyclohexanone, cyclohexyl acetate and phenol, by vacuum distillation. The negative pressure is controlled at -0.095 MPa, the top temperature is 109℃ and the bottom temperature is 190℃. The X oil distillate is then subjected to transesterification, and the remaining X oil distillate is sent to a high-pressure reactor for dehydration.

[0137] Step 2: The X oil distillate, propanol, and catalyst obtained above are pumped into a transesterification reactor for transesterification. The molar ratio of propanol to cyclohexyl acetate is controlled at 4:1. The amount of potassium ethoxide catalyst added is 0.8% of the raw material mass. The reaction temperature of the transesterification reactor is 103℃~121℃, the reaction pressure is 0.01 MPa, the reflux ratio is 3, and the residence time is 0.5 h. The mass content of propyl acetate in the mixture at the top of the transesterification reactor is 60.35%, the mass content of propanol is 38.85%, and the mass content of cyclohexyl alcohol is 0.80%. The bottom mixture of the transesterification reaction column contained 38.13% cyclohexanol, 3.52% cyclohexanone, 14.92% phenol, 46.03% propanol, and 0.60% propyl acetate. The overhead product was directly pumped into the first distillation column for separation, with an absolute pressure of 1.0 MPa and a reflux ratio of 4. After pressurized distillation, propanol and propyl acetate were refluxed back to the first distillation column. The bottom product was propyl acetate with a purity of 99.0% and a water content of ≤0.10%. The bottom liquid of the transesterification reaction column mainly contained cyclohexanol, cyclohexanone, phenol, and propanol. This bottom liquid was pumped to a distillation column. The overhead product of the distillation column, propanol, was distilled back to the transesterification reaction column in vapor form. The bottom product of the distillation column included propanol, cyclohexanol, cyclohexanone, phenol, and a catalyst. The organic mixture contained >95% cyclohexanol + cyclohexanone + phenol and <5% propanol. The bottom product of the distillation column enters the hydrolysis carbonization tower for carbonation treatment. Each feed is 40t, with 1t of water and 6Nm³ of carbon dioxide introduced. 3 The stirring speed was 60 r / min to 125 r / min, the reaction pressure was atmospheric pressure, and the reaction temperature was 70℃. After the carbonation reaction was completed, the mixture was filtered with a filtration precision of 3 μm to 20 μm, a filtration temperature of 60℃, and a filtration pressure of 0.4 MPa, yielding a high-content crude cyclohexanol, cyclohexanone, and phenol mixture. This mixture was then pumped into a second distillation column for vacuum distillation, with the bottom temperature controlled at 80℃ to 120℃, the top temperature of the second distillation column at 80℃ to 85℃, the vacuum degree of the second distillation column at 0.1 MPa, and the reflux ratio in the second distillation column at 3. The top product of the second distillation column included a mixture of water, alcohol, and cyclohexanol. A side stream of 99.5% cyclohexanol was collected for recovery. The bottom product of the second distillation column was returned to the hydrolysis carbonization column for reprocessing.

[0138] Step 3: The distillate obtained above is pumped into a high-pressure reactor. First, 0.8 wt% of anhydrous aluminum chloride catalyst is added to the reactor liquid. The high-pressure reactor is sealed, and stirring is started. After mixing evenly, nitrogen gas is introduced to pressurize to 2.0 MPa, and the temperature is raised to the dehydration reaction temperature of 210℃. The reaction is started and timed for 10 hours. After the reaction, the conversion rate of 2-cyclohexylcyclohexanol reaches 95.5%, and the selectivity of 1-cyclohexylcyclohexene reaches 98.9%. The dehydrated reaction liquid from the high-pressure reactor is filtered to remove the aluminum chloride catalyst powder, and the resulting clear liquid is transferred to a high-pressure cracking reactor.

[0139] Step 4: The filtered and clarified dehydrated reaction solution was pumped into a high-pressure pyrolysis reactor, and 3 wt% of aluminum silicate catalyst was added. The high-pressure reactor was sealed, and stirring was started. After mixing evenly, nitrogen gas was introduced to pressurize to 1.5 MPa, and the temperature was raised to the pyrolysis reaction temperature of 380℃. The reaction was started and timed for 10 hours. After the reaction was completed, the conversion rate of 1-cyclohexylcyclohexene reached 93.7%, and the selectivity of cyclohexene reached 92.3%.

[0140] Step 5: After filtering the catalyst from the reaction solution obtained from the above cracking, crude cyclohexene is obtained and pumped into the third distillation column for atmospheric distillation of cyclohexene. The top temperature is controlled at 80℃~83℃, the bottom temperature at 85℃~95℃, and the reflux ratio is 3~4. Finally, cyclohexene with a mass content of 99.5% and a mass yield of 94.1% is obtained.

[0141] Comparative Example 1

[0142] The process is basically the same as in Example 2, except that step three in Example 2 is omitted, as detailed below:

[0143] Steps one and two are the same as in Example 2;

[0144] Step 3: The distillate obtained above is pumped into a high-pressure pyrolysis reactor, and 3 wt% of the dehydrated reaction solution containing activated alumina catalyst is added. The high-pressure reactor is sealed, and stirring is started. After mixing evenly, nitrogen gas is introduced to pressurize to 1.5 MPa, and the temperature is raised to the pyrolysis reaction temperature of 380℃. The reaction is started and timed for 10 hours. After the reaction is completed, the conversion rate of 1-cyclohexylcyclohexene is 65.8%, and the cyclohexene selectivity is 72.3%.

[0145] Step 4: After filtering the catalyst from the reaction solution obtained from the above cracking, crude cyclohexene is obtained and pumped into the third distillation column for atmospheric distillation of cyclohexene. The top temperature is controlled at 80℃~83℃, the bottom temperature at 85℃~95℃, and the reflux ratio is 3~4. Finally, cyclohexene with a mass content of 99.5% is obtained, and the mass yield is 65.1%.

[0146] Comparative Example 2

[0147] This is basically the same as Example 2, except that no activated alumina catalyst is added in step four, as detailed below:

[0148] Steps one, two, and three are the same as in Example 2;

[0149] Step 4: The above filtered and clarified dehydrated reaction liquid is pumped into a high-pressure pyrolysis reactor. The high-pressure reactor is sealed and the stirring is turned on. After mixing evenly, nitrogen gas is introduced to pressurize to 1.5 MPa and the temperature is raised to the pyrolysis reaction temperature of 380℃. The reaction is started and timed for 10 hours. After the reaction is completed, the conversion rate of 1-cyclohexylcyclohexene is 74.5% and the selectivity of cyclohexene is 81.7%.

[0150] Step 5: After filtering the catalyst from the reaction solution obtained from the above cracking, crude cyclohexene is obtained and pumped into the third distillation column for atmospheric distillation of cyclohexene. The top temperature is controlled at 80℃~83℃, the bottom temperature at 85℃~95℃, and the reflux ratio is 3~4. Finally, cyclohexene with a mass content of 99.5% and a mass yield of 90.5% is obtained.

[0151] As can be seen from Comparative Example 1 and Example 2, when the X oil distillation kettle liquid is directly added to the high-pressure cracking kettle without undergoing a dehydration reaction, the conversion rate of 2-cyclohexylcyclohexanol and the selectivity of cyclohexene are significantly worse, and the cracking reaction is difficult to carry out.

[0152] As can be seen from Comparative Example 2 and Example 2, without the addition of an active alumina pyrolysis catalyst in step four of the pyrolysis reaction, the conversion rate of 1-cyclohexylcyclohexene and the selectivity of cyclohexene are significantly worse, making the pyrolysis reaction difficult to proceed.

[0153] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0154] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for recovering X oil, characterized in that, Includes the following steps: X oil, a byproduct of the dehydrogenation preparation of cyclohexanone from cyclohexanol, is provided; the X oil comprises, by mass percentage: 0-25% cyclohexanol, 0-2% cyclohexanone, 15%-25% cyclohexyl acetate, 10%-15% phenol, 10%-20% 2-cyclohexylcyclohexanone, 10%-30% 2-cyclohexylcyclohexanol, 0-2% 1-cyclohexylcyclohexene, 0-1% cyclohexenylcyclohexanol, 0-1% cyclohexenylcyclohexanone, and 0-5% 2-cyclohexylene-1-cyclohexane. The X oil is subjected to vacuum distillation to obtain distillate and distillate liquid; the pressure of vacuum distillation is -0.095MPa to -0.1MPa, the top temperature of the column is 80℃ to 110℃, and the bottom temperature of the column is 115℃ to 190℃. The distillate was subjected to a dehydration reaction in the presence of a metal halide Lewis acid catalyst to obtain a dehydrated reaction solution. The dehydrated reaction solution was subjected to a pyrolysis reaction under the action of an oxide-type solid acid catalyst to obtain a pyrolysis reaction solution. The pyrolysis reaction solution was subjected to solid-liquid separation, and the liquid phase was subjected to a first distillation treatment to collect cyclohexene at the top of the column.

2. The method for recovering X oil as described in claim 1, characterized in that, The recycling method satisfies at least one of the following characteristics: (1) The oxide-type solid acid catalyst includes at least one of alumina and aluminum silicate; (2) The mass of the oxide-type solid acid catalyst is 2wt% to 5wt% of the mass of the dehydration reaction solution; (3) The pressure of the pyrolysis reaction is 0.8MPa~2MPa, the temperature is 300℃~400℃, and the time is 8h~16h.

3. The method for recovering X oil as described in claim 1, characterized in that, The recycling method satisfies at least one of the following characteristics: (1) The metal halide Lewis acid catalyst includes at least one of aluminum chloride and zinc chloride; (2) The mass of the metal halide Lewis acid catalyst is 0.5wt%~2wt% of the mass of the dehydration reaction solution; (3) The pressure of the dehydration reaction is 1.5MPa~3MPa, the temperature is 180℃~250℃, and the time is 8h~12h.

4. The method for recovering X oil as described in claim 1, characterized in that, The pressure of the first distillation process is 0.09 MPa to 0.11 MPa, the top temperature is 80°C to 83°C, the bottom temperature is 85°C to 95°C, and the reflux ratio is 3 to 4.

5. The method for recovering X oil as described in claim 1, characterized in that, Before carrying out the pyrolysis reaction, the method further includes: performing solid-liquid separation on the dehydrated reaction solution, and taking the liquid phase to carry out the pyrolysis reaction.

6. The method for recovering X oil as described in any one of claims 1 to 5, characterized in that, The recycling method further includes the following steps: The distillate and C2-C4 alcohol are subjected to transesterification in a transesterification tower to obtain the first tower top liquid and the first tower bottom liquid, respectively; the pressure of the transesterification reaction is 0.01 MPa to 0.7 MPa, and the temperature is 80℃ to 125℃. The first overhead liquid is subjected to a second distillation process, and acetate is collected in the bottom of the column. The first column bottom liquid is subjected to a third distillation process, and cyclohexanol is collected from the column side stream.

7. The method for recovering X oil as described in claim 6, characterized in that, The transesterification reaction satisfies at least one of the following characteristics: (1) The molar ratio of the C2~C4 alcohol to the cyclohexyl acetate in the distillate is 3~10:1; (2) The transesterification reaction is carried out in the presence of an alkali metal catalyst for ethanol, wherein the alkali metal catalyst for ethanol includes at least one of sodium ethoxide and potassium ethoxide; (3) The reflux ratio of the transesterification reaction is 1~10; (4) The transesterification reaction takes 0.5h to 2h.

8. The method for recovering X oil as described in claim 7, characterized in that, The absolute pressure of the second distillation process is 0.3 MPa to 1 MPa, and the reflux ratio is 2 to 6.

9. The method for recovering X oil as described in claim 8, characterized in that, The vacuum degree of the third distillation process is 0 MPa to 0.1 MPa, the top temperature is 80°C to 85°C, the bottom temperature is 80°C to 120°C, and the reflux ratio is 3 to 5.

10. The method for recovering X oil as described in any one of claims 7 to 9, characterized in that, Before the first column bottom liquid undergoes the third distillation treatment, the process includes: carbonating the first column bottom liquid with water and carbon dioxide, filtering, and taking the liquid phase for the third distillation treatment. The carbonation treatment satisfies at least one of the following characteristics: (1) The mass ratio of the liquid in the first tower bottom to water is 30~50:1; (2) The mass ratio of the liquid in the first tower bottom to the volume ratio of carbon dioxide is 1t:3Nm. 3 ~8Nm 3 ; (3) The pressure of the carbonation treatment is 0.09 MPa to 0.11 MPa; (4) The temperature of the carbonation treatment is 60℃~90℃.