Method for separating phenol / o-cresol carbolic oil fraction to obtain dephenolized carbolic oil

Abstract

The invention discloses a method for separating phenol / o-cresol phenol oil fractions to obtain dephenolized phenol oil, which comprises the following steps: decompressing phenol-containing coal tar to remove water, fractionating to obtain phenol-containing phenol oil, and decompressing and rectifying to obtain the phenol / o-cresol phenol oil fractions; mixing the phenol / o-cresol phenol oil fraction, methanol and water, introducing hydrogen, reacting under catalysis, removing methanol, and standing and layering the remaining material to obtain a water layer and a phenol-containing material layer; extracting the water layer to obtain an extracted organic phase and a water phase; and combining the phenol-containing material layer with the extracted organic phase, and performing vacuum rectification to obtain phenol / o-cresol dephenolized phenol oil and at least one of 2, 6-xylenol, 2, 4 / 2, 5-xylenol, 2, 4, 6-tricresol, 2, 3, 6-tricresol and 2, 3, 5-tricresol. The dephenolized phenol oil is produced from the phenol / o-cresol phenol oil fraction which is difficult to rectify and separate, one or more phenol products are co-produced, the production cost is low, and the economic value is high.

Description

Technical Field

[0001] The present invention relates to the field of synthesis and separation of coal chemical products, and in particular to a method for separating phenol / o-cresol phenol oil fractions to obtain dephenolized phenol oil. Background Art

[0002] Phenolic compounds in phenolic coal tar are primarily found in the 170-300°C fraction, while volatile phenols are primarily found in the 170-230°C phenol oil fraction. In actual production, coal tar companies will fractionate phenolic coal tar into different distillation ranges of light oil, phenol oil fraction, naphthalene oil fraction, wash oil fraction, anthracene oil fraction, and asphalt, depending on their needs. For medium- and low-temperature phenolic coal tar with high phenol content, the following can also be divided, based on the distribution of phenolic compounds, into: a light oil fraction <170°C, a phenol oil fraction 170-230°C, a tricresol phenol oil fraction 227-240°C, and a hydroquinone phenol oil fraction 240-300°C. The residue is medium-temperature coal tar, which can also be hydrogenated to produce oil products.

[0003] The 170-230°C phenol oil fraction includes one or more of the following: a 170-230°C phenol oil fraction, a 170-185°C mixed phenol oil fraction, a 186-195°C o-cresol oil fraction, a 196-205°C m-cresol oil fraction, a 206-215°C 2,4- / 2,5-xylenol oil fraction, a 216-221°C m- / 3,5-xylenol oil fraction, and a 222-226°C 3,4-xylenol / propylphenol oil fraction. The 240-300°C hydroquinone oil fraction includes a 240-250°C o-catechol oil fraction, a 250-270°C 5-indanol oil fraction, and a 270-300°C resorcinol / hydroquinone fraction.

[0004] At present, in the relevant technology, the method of separating phenolic substances from phenol-containing coal tar includes: first distilling and cutting the phenol-containing coal tar to obtain a 170-230°C phenol oil fraction or a 170-300°C phenol oil fraction, and then extracting crude phenol from the phenol oil fraction by alkali dissolution and acid precipitation or solvent extraction; refining the crude phenol to obtain various phenol products or mixtures such as phenol, o-cresol, tri-cresol, m-cresol, xylenol, etc.; m-cresol, mixed xylenols, mixed tri-cresols, etc. are then separated by physical or chemical methods to obtain m-cresol, p-cresol, 2,5-xylenol, 2,4-xylenol, 3,5-xylenol, 3,4-tri-cresol, m-ethylphenol, p-ethylphenol and other products. There are problems such as the process being relatively complicated and tedious, and the economic benefits are not very good.

[0005] In the phenol / o-cresol phenol oil fraction, phenolic substances generally account for 45-70%, and its phenolic substances are mainly composed of phenol and o-cresol, and may also contain m-p-cresol, o-ethylphenol, etc. The composition of phenolic substances varies with different distillation ranges, including mixed phenol oil fractions with a phenol content of more than 50% in phenolic substances, o-cresol phenol oil fractions with an o-cresol content of more than 50% in phenolic substances, o-cresol / 2,6-xylenol phenol oil fractions with a higher 2,6-xylenol content, etc. Such phenol / o-cresol phenol oil fractions are relatively low in price. Since the boiling point of the dephenolized phenol oil after removing phenolic substances such as phenol and o-cresol from the phenol / o-cresol phenol oil fraction is 180-195° C., the boiling point of phenol is 182° C., and the boiling point of o-cresol is 191° C., the boiling points overlap, making it difficult to obtain the dephenolized phenol oil by distillation, and it is difficult to separate the dephenolized phenol oil and the phenolic substances, and to separate the various phenolic substances, making it difficult to obtain the dephenolized phenol oil and various phenolic substance products respectively. Summary of the Invention

[0006] The present invention is based on the inventors' discovery and understanding of the following facts and problems: Currently, the extraction and separation of phenolic compounds from phenol oil fractions requires alkali dissolution and acid precipitation, solvent extraction, physical or chemical methods, etc., which are complex and tedious processes with poor economic benefits. Furthermore, due to the overlapping boiling points of the dephenolized phenol oil, phenol, and o-cresol in the phenol / o-cresol phenol oil fraction, separation by distillation is difficult.

[0007] 2,6-Xylenol is typically produced through the fixed-bed catalytic methylation of petrochemical-grade phenol with methanol, with o-cresol and 2,4,6-trimethylphenol as by-products. However, petrochemical-grade phenol is relatively expensive, and the resulting o-cresol, 2,6-xylenol, and 2,4,6-trimethylphenol are expensive to produce.

[0008] The present invention aims to solve, at least to a certain extent, one of the technical problems in the related art. To this end, an embodiment of the present invention provides a method for separating a phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil, wherein the phenol / o-cresol phenol oil fraction, from which phenolic substances and dephenolized phenol oil are difficult to separate, is used to produce phenol / o-cresol dephenolized phenol oil, and one or more products selected from 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol, and 2,3,5-trimethylol are co-produced, with low production cost and great economic value.

[0009] The embodiment of the present invention provides a method for separating a phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil, comprising the following steps:

[0010] (1) adding phenol-containing coal tar to a distillation tower, first removing water under reduced pressure, and then fractionating to obtain a slag-free phenol-containing phenol oil with a temperature of ≤300° C.; subjecting the slag-free phenol-containing phenol oil to vacuum distillation to obtain a phenol / o-cresol phenol oil fraction with a distillation range of 180-195° C.; the phenol / o-cresol phenol oil fraction comprises phenolic substances, and the phenolic substances include phenol and o-cresol;

[0011] (2) loading the catalyst into a reactor, mixing the phenol / o-cresol oil fraction, methanol, and water, and then injecting the mixture into the reactor while introducing hydrogen to carry out the reaction; sampling and analyzing, and removing methanol after the desired requirements are met;

[0012] (3) the remaining material after methanol removal is allowed to stand for separation to obtain a water layer and a phenol-containing material layer; the water layer is extracted with phenol / o-cresol dephenolized phenol oil, and the layers are separated to obtain an extracted organic phase and an aqueous phase;

[0013] (4) The phenol-containing material layer is combined with the extracted organic phase, and the combined solution is subjected to vacuum distillation to obtain phenol / o-cresol dephenolized phenol oil, and at least one of 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol.

[0014] Advantages and technical effects brought by the method for separating the phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil in the embodiment of the present invention: the present invention separates the phenol / o-cresol phenol oil fraction to produce phenol / o-cresol dephenolized phenol oil, 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol, and 2,3,5-trimethylol products. A narrow fraction of phenol-containing phenol oil (distillation range 180-195°C, referred to as phenol / o-cresol phenol oil fraction) obtained by distillation of phenol-containing coal tar is used as a raw material. The phenol / o-cresol phenol oil fraction is mixed with methanol and the like and then reacted under a suitable catalyst. The reactions include catalytic methylation of phenolic substances, transposition of methyl groups of cresol or xylenol (on the same benzene ring), catalytic thermal deethylation, and continued methylation of phenol obtained by thermal deethylation, to obtain 2,6-xylenol (boiling point of about 203°C), 2,4 / 2,5-xylenol (boiling point of about 211°C), 2,4,6-trimethylol (boiling point of about 220°C), 2,3,6-trimethylol (boiling point of about 226°C) or 2,3,5-trimethylol (boiling point of about 233°C). The distillation range of the dephenolized phenol oil without phenolic substances is 180-195°C, and its boiling point is significantly lower than that of the phenolic substances after the reaction. There are also obvious differences in the boiling points of the phenolic substances in the reaction products. The dephenolized phenol oil and the phenolic substances can be separated by distillation.

[0015] In the embodiment of the present invention, hydrogen is used to hydrogenate indene and some olefinic substances in the phenol / o-cresol phenol oil fraction under the action of a catalyst, converting them into stable saturated substances, avoiding the generation of various polymers, and facilitating material separation. A small amount of sulfur-containing and nitrogen-containing compounds in the phenol / o-cresol phenol oil fraction can also be removed, resulting in a product with very low sulfide and nitrogen-containing compound contents, fully meeting the quality standards of a polymerizer and a pharmaceutical-grade intermediate. Simultaneously, the dephenolized phenol oil obtained does not require hydrogenation pretreatment and can be directly hydrogenated to produce gasoline and diesel. In order to prevent the methyl radicals removed from cresol, xylenol, and trimethylol from reacting with phenolic substances for methylation, thereby affecting the separation of subsequent products, the present invention catalyzes the reaction of methyl radicals with hydrogen, thereby facilitating the separation and extended development of the phenol / o-cresol phenol oil fraction.

[0016] In some embodiments, in step (1), the phenol-containing coal tar includes phenol-containing coal tar obtained by medium-low temperature coal gasification or medium-low temperature coal pyrolysis;

[0017] And / or, the pressure of the vacuum water removal is -0.01 to -0.07 MPa; the reflux ratio of the vacuum water removal is 0.5 to 5; the number of theoretical plates of the vacuum water removal is 50 to 250;

[0018] and / or, fractionally distilling to obtain a 170-230° C. deslagging phenol-containing phenol oil;

[0019] And / or, the number of theoretical plates of the fractional distillation is 50 to 250;

[0020] and / or, the fractional distillation pressure is -0.07 to -0.1 MPa, and the fractional distillation reflux ratio is 5 to 15;

[0021] And / or, the number of theoretical plates of the vacuum distillation is 150 to 350;

[0022] And / or, the pressure of the vacuum distillation is -0.08 to -0.1 MPa, and the reflux ratio of the vacuum distillation is 10 to 30.

[0023] In some embodiments, in step (1), the mass content of phenolic substances in the phenol / o-cresol oil fraction is 40-75%;

[0024] And / or, the mass content of phenol and o-cresol in the phenolic substances is 10 to 100%;

[0025] And / or, by mass, the phenolic substances include: 5-95% phenol, 5-90% o-cresol, 0-50% 2,6-xylenol, 0-25% m-cresol, 0-20% p-cresol, and 0-5% o-ethylphenol; preferably, by mass, the phenolic substances include: 30-80% phenol, 20-80% o-cresol, 0-5% 2,6-xylenol, 0-5% m-cresol, 0-5% p-cresol, and 0-1% o-ethylphenol.

[0026] In some embodiments, in step (2), the catalyst comprises an iron sulfate aluminum oxide catalyst and an olefin hydrogenation catalyst;

[0027] And / or, the reactor includes at least one of a tank reactor, a fixed bed reactor, a fluidized bed reactor, an ebullient bed reactor, and a transport bed reactor.

[0028] In some embodiments, in step (2), the iron vanadium aluminum oxide catalyst comprises iron vanadium aluminum oxide; the iron vanadium aluminum oxide comprises iron oxide, vanadium oxide and aluminum oxide; the mass ratio of the iron oxide, vanadium oxide and aluminum oxide is 0.5-5:1:0.01-0.5; the iron oxide comprises iron oxide, the vanadium oxide comprises vanadium pentoxide, and the aluminum oxide comprises acidic aluminum oxide;

[0029] And / or, the iron vitriol aluminum oxide catalyst comprises iron vitriol aluminum oxide and a carrier, the carrier comprises silica gel; the mass percentage of the carrier is 10 to 30%;

[0030] and / or, the particle size of the iron sulfate aluminum oxide catalyst is 50 to 200 mesh;

[0031] And / or, when the reactor is a tank reactor, the mass of the iron vitriol aluminum oxide catalyst in the catalyst is 5 to 30% of the mass of the phenol / o-cresol phenol oil fraction;

[0032] And / or, the olefin hydrogenation catalyst comprises at least one of palladium carbon and Raney nickel; the palladium carbon comprises palladium carbon having a palladium element mass percentage of 1 to 5%;

[0033] And / or, the olefin hydrogenation catalyst comprises a partially deactivated olefin hydrogenation catalyst;

[0034] and / or, the particle size of the olefin hydrogenation catalyst is 20 to 120 mesh;

[0035] And / or, in the catalyst, the mass of the olefin hydrogenation catalyst is 0.1 to 5% of the mass of the iron vitriol aluminum oxide catalyst.

[0036] In some embodiments, in step (2), the phenol / o-cresol oil fraction is calculated based on the molar number of phenolic substances contained, and the molar ratio of the phenol / o-cresol oil fraction, methanol and water is 1:4-10:0.3-2.0;

[0037] And / or, the mass of the hydrogen is 0.1 to 3 times the mass of the phenol / o-cresol phenol oil fraction.

[0038] In some embodiments, in step (2), the reaction is carried out at normal pressure or under pressure;

[0039] and / or, the reaction temperature is 300-600° C.;

[0040] And / or, when the reactor is a bed reactor, the liquid hourly space velocity of the reaction is 0.3 to 1.2 h -1 ;

[0041] And / or, when the reactor is a tank reactor, the reaction pressure is 3 to 9 MPa.

[0042] In some embodiments, in step (2), sampling and analysis are performed, and methanol is removed after the desired requirements are met;

[0043] Optionally, achieving the desired requirements includes achieving the desired requirements for o-cresol content and 2,3,6 / 2,4,6-trimethylcyclohexanol content;

[0044] Optionally, sampling and analysis are performed, and the test results are qualified when the mass content of o-cresol is ≤0.5% and the mass content of 2,3,6 / 2,4,6-trimethylcyclohexanol is ≤0.5%;

[0045] Optionally, sampling and analysis are performed. When the mass content of 2,3,6 / 2,4,6-trimethylcyclohexanol is ≥1%, the olefin hydrogenation catalyst in the reactor is replaced with a reusable olefin hydrogenation catalyst with lower activity;

[0046] Optionally, the sampling and analysis is performed by gas chromatography; the gas chromatograph: the detector is a hydrogen flame detector, and the chromatographic column is a chromatographic column specially used for polar phenols;

[0047] Optionally, methanol is removed by distillation, the number of theoretical plates for distillation is 150 to 350, and the reflux ratio is 0.1 to 2.

[0048] In some embodiments, in step (3), the water layer is extracted with phenol / o-cresol dephenolized phenol oil, and the phenol / o-cresol dephenolized phenol oil is 0.1 to 2 times the mass of the water layer material;

[0049] And / or, the phenol / o-cresol dephenolized phenol oil is the phenol / o-cresol dephenolized phenol oil obtained by the previous batch process;

[0050] And / or, after separation, the aqueous phase is sent to a post-processing section.

[0051] In some embodiments, in step (4), the number of theoretical plates of the vacuum distillation is 200 to 300;

[0052] And / or, the pressure of the vacuum distillation is -0.08 to -0.1 MPa;

[0053] and / or, the reflux ratio of the vacuum distillation is 10 to 30;

[0054] And / or, the purity of the 2,6-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol is not less than 99% respectively; the purity of the 2,4 / 2,5-dimethylphenol is not less than 95%. DETAILED DESCRIPTION

[0055] The following describes in detail embodiments of the present invention. The embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0056] A method for separating a phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil according to an embodiment of the present invention comprises the following steps:

[0057] (1) adding phenol-containing coal tar to a distillation tower, first removing water under reduced pressure, and then fractionating to obtain a slag-free phenol-containing phenol oil with a temperature of ≤300° C.; subjecting the slag-free phenol-containing phenol oil to vacuum distillation to obtain a phenol / o-cresol phenol oil fraction with a distillation range of 180-195° C.; the phenol / o-cresol phenol oil fraction comprises phenolic substances, and the phenolic substances include phenol and o-cresol;

[0058] (2) loading the catalyst into a reactor, mixing the phenol / o-cresol oil fraction, methanol, and water, and then injecting the mixture into the reactor while introducing hydrogen to carry out the reaction; sampling and analyzing, and removing methanol after the desired requirements are met;

[0059] (3) the remaining material after methanol removal is allowed to stand for separation to obtain a water layer and a phenol-containing material layer; the water layer is extracted with phenol / o-cresol dephenolized phenol oil, and the layers are separated to obtain an extracted organic phase and an aqueous phase;

[0060] (4) The phenol-containing material layer is combined with the extracted organic phase, and the combined solution is subjected to vacuum distillation to obtain phenol / o-cresol dephenolized phenol oil, and at least one of 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol.

[0061] The method of separating the phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil according to the embodiment of the present invention separates the phenol / o-cresol phenol oil fraction to produce phenol / o-cresol dephenolized phenol oil, 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol, and 2,3,5-trimethylol products. A narrow fraction of phenol-containing phenol oil (distillation range 180-195°C, referred to as phenol / o-cresol phenol oil fraction) obtained by distillation of phenol-containing coal tar is used as a raw material. The phenol / o-cresol phenol oil fraction is mixed with methanol and the like and then reacted under a suitable catalyst. The reactions include catalytic methylation of phenolic substances, transposition of methyl groups of cresol or xylenol (on the same benzene ring), catalytic thermal deethylation, and continued methylation of phenol obtained by thermal deethylation, to obtain 2,6-xylenol (boiling point of about 203°C), 2,4 / 2,5-xylenol (boiling point of about 211°C), 2,4,6-trimethylol (boiling point of about 220°C), 2,3,6-trimethylol (boiling point of about 226°C) or 2,3,5-trimethylol (boiling point of about 233°C). The distillation range of the dephenolized phenol oil without phenolic substances is 180-195°C, and its boiling point is significantly lower than that of the phenolic substances after the reaction. There are also obvious differences in the boiling points of the phenolic substances in the reaction products. The dephenolized phenol oil and the phenolic substances can be separated by distillation.

[0062] In an embodiment of the present invention, phenol, o-cresol, p-cresol, 2,6-xylenol, and the like in the phenol / o-cresol phenol oil fraction react with methanol under a suitable catalyst to produce a phenol oil fraction containing 2,6-xylenol and 2,4,6-trimethylphenol. Simultaneously, o-cresol and p-cresol partially translocate to m-cresol, and 2,6-xylenol translocates to 2,5-xylenol, 2,3-xylenol, 3,5-xylenol, and the like, which then react with methanol to produce 2,3,6-trimethylphenol, 2,3,5-trimethylphenol, and the like. At higher temperatures, 2,6-xylenol and cresol may also undergo methyl shedding reactions to produce cresol and phenol, which then react with methanol to produce 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylphenol, and 2,3,6-trimethylphenol. A methyl translocation reaction of trimethylphenol may also occur (on the same benzene ring). Since the boiling point of the dephenolized phenol oil after removing phenol, o-cresol and other phenolic substances from the phenol / o-cresol phenol oil fraction is 180-195°C, and the boiling points of 2,6-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol and 2,3,5-trimethylol are 203°C, 220°C, 226°C and 233°C respectively, which are 8°C, 25°C, 31°C and 38°C different from the boiling points of the dephenolized phenol oil, dephenolized phenol oil, 99% 2,6-xylenol, 99% 2,4,6-trimethylol, 99% 2,3,6-trimethylol, 99% 2,3,5-trimethylol, etc. can be obtained by distillation, thereby separating the dephenolized phenol oil and phenolic substances.

[0063] In the embodiment of the present invention, hydrogen is used to hydrogenate indene and some olefinic substances in the phenol / o-cresol phenol oil fraction under the action of a catalyst, converting them into stable saturated substances, avoiding the generation of various polymers, and facilitating material separation. A small amount of sulfur-containing and nitrogen-containing compounds in the phenol / o-cresol phenol oil fraction can also be removed, resulting in a product with very low sulfide and nitrogen-containing compound contents, fully meeting the quality standards of a polymerizer and a pharmaceutical-grade intermediate. Simultaneously, the dephenolized phenol oil obtained does not require hydrogenation pretreatment and can be directly hydrogenated to produce gasoline and diesel. In order to prevent the methyl radicals removed from cresol, xylenol, and trimethylol from reacting with phenolic substances for methylation, thereby affecting the separation of subsequent products, the present invention catalyzes the reaction of methyl radicals with hydrogen, thereby facilitating the separation and extended development of the phenol / o-cresol phenol oil fraction.

[0064] In an embodiment of the present invention, the phenol / o-cresol phenol oil fraction that is difficult to separate from phenolic substances and dephenolized phenol oil is produced to obtain phenol / o-cresol dephenolized phenol oil, 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, 2,3,5-trimethylphenol products. The present invention also involves a transfer reaction of some cresols and dimethylphenol methyl groups, and the products of these reactions react with methanol to generate 2,4,6-trimethylphenol and 2,3,6-trimethylphenol, as well as 2,3,5-trimethylphenol. The method of the present invention is different from the method of producing 2,6-dimethylphenol and 2,4,6-trimethylphenol using phenols such as petrochemical phenol, pure o-cresol, pure 2,4-dimethylphenol, and industrial phenol as raw materials, and is also different from the method of producing 2,3,6-trimethylphenol using phenols such as pure meta-cresol, pure 2,3-dimethylphenol, and pure 2,5-dimethylphenol as raw materials.

[0065] In the embodiments of the present invention, the extraction of phenolic products from traditional phenol-containing coal tar generally requires the following steps: the phenol-containing coal tar is first distilled and cut to obtain a phenol oil fraction at 170 to 230° C., and the phenol oil fraction is then extracted with an alkali solution and acid precipitation method or a solvent extraction method; the crude phenol is refined to obtain various phenolic products or mixtures; and mixed phenol (a mixture of phenol and o-cresol), o-cresol fraction (containing 2,6-xylenol), m-cresol, mixed xylenols, mixed trimethylols, etc. are then separated by physical or chemical methods to obtain products such as phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 2,4-xylenol, 3,5-xylenol, 3,4-trimethylol, m-ethylphenol, and p-ethylphenol, which have the problems of a relatively complicated process and poor economic benefits.

[0066] In the embodiment of the present invention, a catalytic methylation reaction is used to separate the phenol / o-cresol phenol oil fraction. Since a fully usable solid catalyst is used, the catalyst can be applied universally and substantially no solid waste is generated. Since most of the catalyst is applied universally, relatively little wastewater needs to be treated.

[0067] In the embodiment of the present invention, a catalytic methylation reaction is carried out using an inexpensive phenol / o-cresol phenol oil fraction raw material and methanol, and the methylation reaction product phenol oil solution is distilled to obtain two or more of phenol / o-cresol dephenolized phenol oil, 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol, 2,3,5-trimethylol, etc., thereby expanding the application field of the phenol / o-cresol phenol oil fraction, reducing the difficulty of treating phenol-containing coal tar, and realizing the separation of the phenol / o-cresol phenol oil fraction.

[0068] In the embodiments of the present invention, the average price of the phenol-containing coal tar used as the starting raw material is 3,000 yuan / ton (the prices of pure phenol and o-cresol are 8,000 yuan / ton and 14,000 yuan / ton, respectively), while the phenol / o-cresol dephenolized phenol oil produced is 4,000 yuan / ton, and the prices of 2,6-dimethylphenol and 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol are 20,000 yuan / ton, 25,000 yuan / ton, 40,000 yuan / ton, and 300,000 yuan / ton, respectively. The production cost is low and the economic value is large.

[0069] In some embodiments, in step (1), the phenol-containing coal tar includes phenol-containing coal tar obtained by medium-low temperature coal gasification or medium-low temperature coal pyrolysis.

[0070] In some embodiments, in step (1), the pressure of the reduced pressure water removal is -0.01 to -0.07 MPa, specifically, for example, -0.01 MPa, -0.02 MPa, -0.03 MPa, -0.04 MPa, -0.05 MPa, -0.06 MPa, -0.07 MPa, preferably, -0.04 to -0.06 MPa; the reflux ratio of the reduced pressure water removal is 0.5 to 5, specifically, for example, 0.5, 1, 2, 3, 4, 5; the number of theoretical plates of the reduced pressure water removal is 50 to 250, specifically, for example, 50, 80, 100, 120, 150, 200, 250.

[0071] In some embodiments, in step (1), fractional distillation is performed to obtain a phenol-containing oil with a temperature of ≤300°C. This fractional distillation may also be referred to as rectification, and the phenol-containing oil with a ...

[0072] In some embodiments, in step (1), fractional distillation is performed to obtain a phenol-containing phenol oil having a temperature of ≤300°C;

[0073] Optionally, fractionation is performed using a rectification column;

[0074] Fractional distillation obtains phenol-containing phenol oil at 170-230°C, specifically, for example, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, and 230°C;

[0075] The number of theoretical plates of the fractional distillation is 50 to 250, specifically, for example, 50, 80, 100, 120, 150, 200, and 250; the pressure of the fractional distillation is -0.07 to -0.1 MPa, specifically, for example, -0.07 MPa, -0.08 MPa, -0.09 MPa, and -0.1 MPa; the reflux ratio of the fractional distillation is 5 to 15, specifically, for example, 5, 8, 10, 12, and 15.

[0076] In some embodiments, in step (1), the vacuum distillation is carried out using a high-efficiency distillation tower. In the embodiment of the present invention, the phenol-containing phenol oil removed from the residue is distilled using a high-efficiency distillation tower to obtain various narrow fractions including a phenol / o-cresol phenol oil fraction, which are used to further separate the phenol oil and phenol.

[0077] In some embodiments, in step (1), the phenol-containing phenol oil from the deslagging is subjected to vacuum distillation to obtain a phenol / o-cresol phenol oil fraction with a distillation range of 180-195°C; the present invention can obtain any phenol / o-cresol phenol oil narrow fraction between 180-195°C, specifically, the distillation endpoint or distillation range can be 180-183°C, 184-187°C, 188-191°C, 192-195°C, 180-190°C, 185-195°C;

[0078] Optionally, the number of theoretical plates of the vacuum distillation is 150 to 350, specifically, for example, 150, 200, 250, 300, 350, preferably, 200 to 300; the pressure of the vacuum distillation is -0.08 to -0.1 MPa, specifically, for example, -0.08 MPa, -0.085 MPa, -0.09 MPa, -0.095 MPa, -0.1 MPa; the reflux ratio of the vacuum distillation is 10 to 30, specifically, for example, 10, 15, 20, 25, 30.

[0079] In some embodiments, in step (1), the mass content of phenolic substances in the phenol / o-cresol oil fraction is 40-75%, specifically, for example, 40%, 45%, 50%, 60%, 65%, 70%, 75%, preferably, 45-65%.

[0080] In some embodiments, in step (1), the mass content of the dephenolized phenol oil without phenolic substances in the phenol / o-cresol phenol oil fraction is 25-60%, specifically, for example, 25%, 30%, 40%, 50%, 60%.

[0081] In some embodiments, in step (1), the mass content of phenol and o-cresol in the phenolic substance is 10-100%, specifically, for example, 10%, 20%, 40%, 60%, 80%, 90%, 95%, 100%;

[0082] Optionally, the phenolic substances include, by mass: 5-95% (e.g., 5%, 10%, 20%, 30%, 50%, 80%, 90%, 95%) of phenol, 5-90% (e.g., 5%, 10%, 20%, 50%, 80%, 90%) of o-cresol, 0-50% (e.g., 0, 5%, 10%, 20%, 50%) of 2,6-dimethylphenol, 0-25% (e.g., 0, 5%, 10%, 15%, 20%, 25%) of m-cresol, 0-20% (e.g., 0, 5%, 10%, 15%, 20%) of p-cresol, and 0-5% (e.g., 0, 1%, 2%, 3%, 4%, 5%) of o-ethylphenol;

[0083] Preferably, the phenolic substances include, by mass, 30-80% of phenol, 20-80% of o-cresol, 0-5% of 2,6-dimethylphenol, 0-5% of m-cresol, 0-5% of p-cresol, and 0-1% of o-ethylphenol.

[0084] In some embodiments, in step (2), the reactor comprises at least one of a tank reactor, a fixed bed reactor, a fluidized bed reactor, an ebullient bed reactor, and a transport bed reactor, preferably a fixed bed reactor.

[0085] In some embodiments, in step (2), the catalyst comprises an iron sulfate aluminum oxide catalyst and an olefin hydrogenation catalyst;

[0086] Optionally, the iron vanadium aluminum oxide catalyst comprises iron vanadium aluminum oxide and a carrier; the iron vanadium aluminum oxide comprises iron oxide, vanadium oxide and aluminum oxide; the mass ratio of the iron oxide, vanadium oxide and aluminum oxide is 0.5-5 (for example, 0.5, 1, 2, 3, 4, 5): 1: 0.01-0.5 (for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5); the iron oxide comprises at least one of iron oxide or ferrosoferric oxide, the vanadium oxide comprises vanadium pentoxide, and the aluminum oxide comprises vanadium pentoxide. The catalyst comprises acidic alumina; the carrier comprises silica gel, that is, the ferrovanadium aluminum oxide catalyst is a silica gel-supported ferrovanadium aluminum oxide catalyst; in the ferrovanadium aluminum oxide catalyst, the mass percentage of the carrier is 10-30%, specifically, for example, 10%, 20%, 30%; the mass percentage of the ferrovanadium aluminum oxide is 70-90%; the particle size of the ferrovanadium aluminum oxide catalyst is 50-200 mesh, specifically, for example, 50-80 mesh, 90-120 mesh, 130-160 mesh, 170-200 mesh;

[0087] Optionally, the olefin hydrogenation catalyst comprises at least one of palladium carbon and Raney nickel; the palladium carbon comprises palladium carbon having a palladium element mass percentage of 1 to 5%, specifically, for example, 1%, 2%, 3%, 4%, 5%; the particle size of the olefin hydrogenation catalyst is 20 to 120 mesh, specifically, for example, 20 to 40 mesh, 40 to 60 mesh, 60 to 80 mesh, 80 to 100 mesh, 100 to 120 mesh;

[0088] Optionally, the olefin hydrogenation catalyst includes a partially deactivated olefin hydrogenation catalyst; the olefin hydrogenation catalyst is a partially deactivated olefin hydrogenation catalyst; there is no special limitation on the partially deactivated olefin hydrogenation catalyst, and it can be a partially deactivated olefin hydrogenation catalyst;

[0089] Optionally, in the catalyst, the mass of the olefin hydrogenation catalyst is 0.1 to 5% of the mass of the iron vitriol aluminum oxide catalyst, specifically, for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%;

[0090] The method of the present invention has no particular restrictions on the source and preparation method of the catalyst. For example, the iron alum aluminum oxide catalyst can be prepared by conventional methods in the art, or the iron alum oxide catalyst and acidic alumina can be mixed to form the iron alum aluminum oxide catalyst of the present invention. The olefin hydrogenation catalyst can be purchased, and the olefin hydrogenation catalyst used by the hydrogenation manufacturer can be purchased or the purchased olefin hydrogenation catalyst can be mixed with an olefin hydrogenation catalyst with low application activity for use.

[0091] In an embodiment of the present invention, the phenol / o-cresol phenol oil fraction is mixed with methanol and the like and reacted under a catalyst. The reaction includes a catalytic methylation reaction of phenols, a transposition reaction of cresol or xylenol methyl groups (on the same benzene ring), a catalytic thermal deethylation reaction, and a further methylation reaction of the phenol obtained by thermal deethylation to obtain 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol, etc. or 2,3,5-trimethylol. Using hydrogen, indene and some olefins in the phenol / o-cresol phenol oil fraction can be hydrogenated under the action of a catalyst; a small amount of sulfur-containing and nitrogen-containing compounds in the phenol / o-cresol phenol oil fraction can also be removed. In order to prevent the methyl radicals removed from cresol, xylenol, and trimethylol from reacting with phenols to form a methylation reaction, thereby affecting the separation of subsequent products, the catalyst of the present invention catalyzes the reaction of methyl radicals with hydrogen, which contributes to the separation and extended development of the phenol / o-cresol phenol oil fraction.

[0092] In the embodiments of the present invention, in order to prevent the ethylene and methyl radicals removed from o-ethylphenol, cresol, xylenol, and trimethylol from reacting with phenolic substances and affecting the separation of subsequent products, the present invention uses a partially deactivated olefin hydrogenation catalyst to catalyze the reaction of ethylene, methyl radicals and hydrogen, which facilitates the separation and extended development of the phenol / o-cresol phenol oil fraction.

[0093] In an embodiment of the present invention, the present invention can convert the lower-value 2,6-dimethylphenol in the product into 2,5-dimethylphenol and 3,5-dimethylphenol, and convert the 2,4,6-trimethylphenol and other components into the higher-value 2,3,5-trimethylphenol and 2,3,6-trimethylphenol by adjusting the amount of acidic alumina used and performing a transposition reaction of dimethylphenol, cresol, and trimethylphenol. The mass ratio of iron oxide, vanadium oxide, and aluminum oxide is 0.5-5:1:0.01-0.5. When the proportion of acidic alumina and other components is high and the reaction temperature is high, deethylation of o-ethylphenol and demethylation of cresol and dimethylphenol can occur. The removed ethylene and other components react with hydrogen to form ethane and methane, thereby substantially eliminating ethylphenol from the reaction product. This facilitates the purification of dimethylphenol and trimethylphenol, resulting in better product quality.

[0094] In an embodiment of the present invention, an olefin hydrogenation catalyst and hydrogen that are not very active are used, and the indene and some olefinic substances in the phenol / o-cresol phenol oil fraction can be hydrogenated to convert them into stable saturated substances, thereby avoiding the generation of various polymers and facilitating material separation. An olefin hydrogenation catalyst and hydrogen that are not very active are used to control the hydrogenation reaction so that no hydrogenation of the benzene ring and dehydration reaction on the hydroxyl group occur. If an overly active hydrogenation catalyst is used, for example, a highly active fresh palladium-carbon catalyst, at a high temperature, a small amount of hydrogenation reaction on the benzene ring will produce cyclohexanol substances, resulting in loss of phenolic materials and affecting subsequent separation. If 2,3,6 / 2,4,6-trimethylcyclohexanol is detected to be ≥1%, it indicates that the activity of the hydrogenation catalyst is too high and it is necessary to replace an olefin hydrogenation catalyst with a lower activity to avoid loss of phenolic materials and affecting subsequent separation.

[0095] In the embodiment of the present invention, a small amount of hydrogenation catalyst and hydrogen are used in the catalyst, so that a small amount of sulfur-containing and nitrogen-containing compounds in the phenol / o-cresol phenol oil fraction can be removed, thereby obtaining 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol with very low contents of sulfides and nitrogen-containing compounds, which can fully meet the quality indicators of polymerization agents and pharmaceutical-grade intermediates; at the same time, the obtained dephenolized phenol oil does not need to be pretreated by hydrogenation and can be directly hydrogenated to produce gasoline and diesel.

[0096] In some embodiments, in step (2), when the reactor is a tank reactor, the mass of the iron sulfate aluminum oxide catalyst in the catalyst is 5 to 30% of the mass of the phenol / o-cresol phenol oil fraction, specifically, for example, 5%, 10%, 15%, 20%, 25%, 30%.

[0097] In some embodiments, in step (2), the catalyst can be reused; when low reaction conversion rate and selectivity are detected, the catalyst is replaced.

[0098] In some embodiments, in step (2), the catalyst is loaded into a reactor, and the phenol / o-cresol oil fraction, methanol and water are mixed and then injected into the reactor; alternatively, they are injected into the reactor through a plunger metering pump; alternatively, they are injected into the reactor through a preheater through a plunger metering pump.

[0099] In some embodiments, in step (2), the phenol / o-cresol oil fraction is calculated based on the molar number of phenolic substances contained, and the molar ratio of the phenol / o-cresol oil fraction (molar number of phenolic substances contained), methanol and water is 1:4-10 (for example, 4, 5, 6, 7, 8, 9, 10):0.3-2.0 (for example, 0.3, 0.6, 0.9, 1.0, 1.2, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0).

[0100] In the embodiments of the present invention, the molar ratio of the phenol / o-cresol oil fraction, methanol, and water is 1:4-10:0.3-2.0, which is beneficial for improving product quality. Excessive methanol usage can produce small amounts of impurities such as tetracresol and pentacresol; while too little methanol usage can produce large amounts of cresol and xylenol, affecting the separation of phenol oil and phenol and increasing operating costs. Adding water can dilute the materials and prevent carbon accumulation on the catalyst surface. Excessive water usage increases wastewater production; too little water usage can cause carbon accumulation on the catalyst surface, affecting its effectiveness.

[0101] In some embodiments, in step (2), the mass of the hydrogen is 0.1 to 3 times the mass of the phenol / o-cresol oil fraction, specifically, for example, 0.1 times, 0.2 times, 0.5 times, 1 times, 2 times, 3 times, preferably, 0.2 to 2 times.

[0102] In the embodiment of the present invention, the mass of hydrogen is 0.1 to 3 times the mass of the phenol / o-cresol phenol oil fraction, which is conducive to ensuring that the unsaturated olefins, sulfur compounds, nitrogen compounds, indenes in the phenol / o-cresol phenol oil fraction, as well as a small amount of ethylene and methyl radicals released by the reaction are reacted completely, and it can also be ensured that the phenolic material after the methylation reaction has few impurities, and it is easy to separate and refine to obtain high-purity various xylenols and trimethylols. When the hydrogen consumption is too low, it is not conducive to the removal of unsaturated olefins, sulfur compounds, nitrogen compounds, and indenes, resulting in a high degree of difficulty in product purification, a large number of impurities, and a dark color; when the hydrogen consumption is too high, it is likely to cause the generation of reactions such as the hydrogenation reaction on the phenyl ring of the phenolic material and the shedding of the phenolic hydroxyl group.

[0103] In some embodiments, in step (2), the reaction is carried out at normal pressure or under pressure; the reaction temperature is 300-600° C., specifically, for example, 300° C., 400° C., 500° C., 600° C.;

[0104] When the reactor is a bed reactor (fixed bed reactor, fluidized bed reactor, ebullient bed reactor or transport bed reactor), the liquid hourly space velocity of the reaction is 0.3 to 1.2 h -1 , specifically, for example, 0.3h -1 , 0.6h -1 , 0.9h -1, 1.2h -1 , the liquid hourly space velocity is the volume of the liquid reaction mixture (before entering the bed) (a mixture of phenol / o-cresol oil fraction, methanol and water) treated per unit volume of catalyst per hour;

[0105] When the reactor is a tank reactor, the reaction pressure is 3 to 9 MPa, specifically, for example, 3 MPa, 5 MPa, 8 MPa, 9 MPa.

[0106] In some embodiments, in step (2), sampling and analysis are performed, and methanol is removed after the desired requirements are met;

[0107] Optionally, achieving the desired requirements includes achieving the desired requirements for o-cresol content and 2,3,6 / 2,4,6-trimethylcyclohexanol content;

[0108] Optionally, sampling and analysis are performed, and the test results are qualified when the mass content of o-cresol is ≤0.5% and the mass content of 2,3,6 / 2,4,6-trimethylcyclohexanol (2,3,6-trimethylcyclohexanol and 2,4,6-trimethylcyclohexanol) is ≤0.5%;

[0109] Optionally, when the desired requirements are not met (unqualified), if the o-cresol content is too high, the liquid hourly space velocity is reduced, the molar ratio of methanol to phenolic substances in the raw material phenol / o-cresol phenol oil fraction is increased, the reaction temperature is increased, etc.;

[0110] Optionally, sampling and analysis show that when the mass content of 2,3,6 / 2,4,6-trimethylcyclohexanol is ≥1%, it indicates that the activity of the olefin hydrogenation catalyst is too high, and the olefin hydrogenation catalyst in the reactor is replaced with an olefin hydrogenation catalyst with lower activity.

[0111] In some embodiments, in step (2), the sampling and analysis are performed using a gas chromatograph; the gas chromatograph uses a hydrogen flame detector as a detector, and a chromatographic column used for polar phenols.

[0112] In some embodiments, in step (2), when sampling and analysis show that the required requirements are not met, the conversion rate of raw materials and intermediate products can be improved by at least one of reducing the material flow rate (extending the residence time), increasing the ratio of methanol to phenol in the starting material, and increasing the reaction temperature.

[0113] In some embodiments, in step (2), when the reaction adopts a bed reactor (fixed bed reactor, fluidized bed reactor, ebullient bed reactor or transport bed reactor), optionally, the reaction adopts a fixed bed reactor, the reaction is a fixed bed reaction, and the fixed bed reaction is a continuous reaction;

[0114] Optionally, sampling and analysis are performed, and methanol is removed after the desired requirements are met; specifically, sampling and analysis are performed, and the gasification reaction product is condensed, and the obtained condensate is added to a distillation tower to remove methanol.

[0115] In some embodiments, in step (2), when a tank reactor is used, sampling and analysis are performed, and after the desired requirements are met, methanol is removed; specifically, sampling and analysis are performed, and after the desired requirements are met, the methanol is filtered; the filtrate is added to a distillation tower (tower) to remove methanol; and after filtration, the filter cake is reused. In the embodiments of the present invention, when a tank reactor is used, the catalyst in the filter cake can be reused, and substantially no solid waste is generated.

[0116] In some embodiments, in step (2), methanol is removed by distillation, and the theoretical number of plates for distillation removal of methanol is 150 to 350, specifically, for example, 150, 200, 250, 300, 350, preferably, 200 to 300; methanol is removed at normal pressure to (slightly) negative pressure; the reflux ratio is 0.1-2, specifically, for example, 0.1, 0.5, 1, 1.5, 2.

[0117] In some embodiments, in step (2), a small amount of water is also removed during the removal of methanol; optionally, the removed methanol and water jacket are used in the next batch of reactions.

[0118] In some embodiments, in step (3), the water layer is extracted with phenol / o-cresol dephenolized phenol oil, and the phenol / o-cresol dephenolized phenol oil is 0.1 to 2 times the mass of the water layer material, specifically, for example, 0.1 times, 0.2 times, 0.3 times, 0.4 times, 0.5 times, 1 times, 1.5 times, 2.0 times.

[0119] In some embodiments, in step (3), the phenol / o-cresol dephenolized phenol oil is the phenol / o-cresol dephenolized phenol oil obtained by the previous batch treatment; alternatively, the phenol / o-cresol dephenolized phenol oil is the phenol / o-cresol dephenolized phenol oil obtained by the previous batch treatment.

[0120] In some embodiments, in step (3), the aqueous phase is sent to a post-processing section after stratification; optionally, it is sent to a wastewater treatment section of the post-processing section.

[0121] In some embodiments, in step (4), vacuum distillation is performed to obtain phenol / o-cresol dephenolized phenol oil, and at least one of 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol is also obtained. In other words, vacuum distillation is performed to obtain at least two of phenol / o-cresol dephenolized phenol oil, 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol.

[0122] In some embodiments, in step (4), the combined solution is added to a distillation kettle for vacuum distillation; the number of theoretical plates of the vacuum distillation is 200 to 300, specifically, for example, 200, 250, or 300.

[0123] In some embodiments, in step (4), the pressure of the vacuum distillation is -0.08 to -0.1 MPa, specifically, for example, -0.08 MPa, -0.085 MPa, -0.09 MPa, -0.095 MPa, -0.1 MPa; the reflux ratio of the vacuum distillation is 10 to 30, specifically, for example, 10, 15, 20, 25, 30.

[0124] In some embodiments, in step (4), the purity (mass content) of the 2,6-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol is not less than 99% respectively; the purity of the 2,4 / 2,5-dimethylphenol is not less than 95%, and the mass content of 95% of the crude 2,4 / 2,5-dimethylphenol after purification by crystallization is not less than 99%.

[0125] In some embodiments, in step (4), the indene content in the phenol / o-cresol dephenolized phenol oil is not higher than 0.15%, the nitride content is not higher than 1.2 ppm, and the sulfide content is not higher than 0.9 ppm.

[0126] In some embodiments, in step (4), the nitrogen content in the 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol is not higher than 0.9 ppm, and the sulfide content is not higher than 0.7 ppm.

[0127] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way.

[0128] Example 1

[0129] A method for separating a phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil comprises the following steps:

[0130] Step 1: Fraction cutting

[0131] 3,000,000 parts of phenol-containing coal tar from coal pyrolysis of an energy enterprise in Xinjiang were added to the kettle of a distillation tower (100 theoretical plates). First, 15,178 parts of water were removed at -0.05 MPa and a reflux ratio of 0.5 to 5. Then, distillation was carried out under reduced pressure (-0.07 to -0.1 MPa) and a reflux ratio of 5 to 10 to obtain 40,518 parts of a light oil fraction with a distillation range of <170°C and 413,628 parts of a phenol oil fraction with a distillation range of 170 to 230°C.

[0132] Then, 137,876 parts of the 170-230°C phenol oil fraction were added to a high-efficiency distillation tower (with 250 theoretical plates) and subjected to vacuum distillation at -0.08 to -0.09 MPa and a reflux ratio of 10 to 25 to obtain 35,375 parts of a 180-195°C phenol / o-cresol phenol oil fraction. Sampling and analysis showed a phenol content of 56.54%, with the phenol content comprising 53.6% phenol, 36.1% o-cresol, 4.69% 2,6-xylenol, 4.75% m-p-cresol, 0.62% o-ethylphenol, and 0.24% others. Simultaneous analysis revealed 1.33% indene, 0.11% nitrogen-containing compounds, and 0.05% sulfide.

[0133] Step 2: Synthesis and separation of 2,6-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, etc.

[0134] 600 parts of a ferroalloy aluminum oxide catalyst (60-80 mesh, with a mass ratio of iron oxide to vanadium pentoxide and acidic alumina of 1:1:0.5) prepared by loading ferroalloy aluminum oxide on silica gel and 30 parts of 1.5% palladium carbon (40-60 mesh) were loaded into a fixed bed reactor, and 35375 parts of a phenol / o-cresol phenol oil fraction at 180-195°C (15374 parts of non-phenolic phenol oil, 10720.5 parts of phenol, 7220.4 parts of o-cresol, 938.1 parts of 2,6-dimethylphenol, 1,3 ... A mixture of 950.0 parts of p-cresol, 124.0 parts of o-ethylphenol, 48.0 parts of other phenols), 42370 parts of methanol and 7150 parts of water (6.66 times and 2.0 times the molar number of phenolic substances in the phenol / o-cresol oil fraction, respectively) was injected into the reactor through a plunger metering pump via a preheater, and at the same time, 16690 parts of quantitative hydrogen (0.5 times the mass of the phenol / o-cresol oil fraction) was uniformly introduced into the fixed-bed reactor. The mixture was heated at normal pressure, 600°C and a liquid hourly space velocity of 0.7h -1 The reaction was carried out under the conditions of 100% conversion of o-cresol and 0.01% mass content of 2,3,6 / 2,4,6-trimethylcyclohexanol, which was qualified. The condensate was added to the still of a rectifying kettle (theoretical plate number is about 250) with a reflux ratio of 0.1-2 and the solvent was removed under normal pressure to obtain 25549.8 parts of methanol and 1118 parts of water, which were applied to the next batch of methylation reaction;

[0135] In the reaction, while phenol, o-cresol, p-cresol, m-cresol, 2,6-xylenol and the like react with methanol to generate 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol and the like, o-ethylphenol is deethylated to generate phenol, a small amount of cresol and xylenol are demethylated to generate phenol and cresol, and the ethylene and methyl radicals are reacted with hydrogen to generate ethane and methane. At this time, the phenol and cresol with the ethyl and methyl groups removed react with methanol to obtain 2,6-xylenol, 2,4 / 2,5-xylenol, 2,4,6-trimethylol, 2,3,6-trimethylol and the like. 6-trimethylphenol; o-cresol and p-cresol are converted into m-cresol, 2,6-xylenol is converted into 2,5-xylenol, 3,5-xylenol, 2,3-xylenol, 2,4-xylenol, etc., 2,5-xylenol, 3,5-xylenol, 2,3-xylenol, 2,4-xylenol react with methanol to generate 2,3,6-trimethylphenol, 2,3,5-trimethylphenol, 2,4,6-trimethylphenol; finally, under partial deactivation and palladium-carbon catalysis, indene, methylindene, unsaturated olefins, sulfides, nitrogen compounds, etc. are hydrogenated to generate indan, methylindan, saturated alkanes or cycloalkanes, hydrogen sulfide, ammonia, etc.

[0136] The remaining material after removing the methanol is then allowed to stand and separate into layers to obtain a water layer and a phenol-containing material layer, respectively. The water layer is extracted with 5,000 parts of phenol / o-cresol dephenolized phenol oil obtained in the previous batch, and separated into layers to obtain an extracted organic phase and an aqueous phase, respectively. The aqueous phase is sent for further treatment; the phenol-containing material layer (organic material layer) and the extracted organic phase (the dephenolized phenol oil solution of phenol obtained by extraction of the water layer) are combined to obtain 45,663.3 parts of a phenol material solution to be distilled (including 20,066.4 parts of dephenolized oil, 7,771.5 parts of 2,6-xylenol, 1,231.4 parts of 2,4-xylenol / 2,5-xylenol, 11,543 parts of 2,4,6-trimethylol, 3,528.3 parts of 2,3,6-trimethylol, 1,253 parts of 2,3,5-xylenol, and 269.7 parts of others).

[0137] 45663.3 parts of the above phenolic material solution to be rectified were added to a distillation kettle (theoretical plate number is about 250), and vacuum distilled at -0.085 to -0.09 MPa and a reflux ratio of 10 to 30 to obtain:

[0138] 20116.8 parts of phenol / o-cresol dephenolized phenol oil (analysis of phenol / o-cresol dephenolized phenol oil: indene content 0.13%, nitrogen compound 1.2 ppm, sulfide 0.9 ppm);

[0139] 99.6% 2,6-dimethylphenol 7662.3 parts (nitride 0.5 ppm, sulfide 0.4 ppm);

[0140] 95.1% 2,4-dimethylphenol / 1268.9 parts of 2,5-dimethylphenol (0.9 ppm nitrogen compound, 0.6 ppm sulfide compound);

[0141] 99.5% 2,4,6-trimethylphenol 10823.7 parts (nitride 0.7 ppm, sulfide 0.5 ppm);

[0142] 99.7% 2,3,6-trimethylphenol 3167.3 parts (nitride 0.7 ppm, sulfide 0.6 ppm);

[0143] 99.1% 2,3,5-trimethylphenol 1169.5 parts (nitrogen compound 0.9 ppm, sulfide 0.7 ppm).

[0144] Example 2

[0145] A method for separating a phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil comprises the following steps:

[0146] Step 1: Fraction cutting

[0147] 3,000,000 parts of phenol-containing coal tar from coal pyrolysis of an energy enterprise in Xinjiang were added to the kettle of a distillation tower (100 theoretical plates). First, 15,178 parts of water were removed at -0.05 MPa and a reflux ratio of 0.5 to 5. Then, distillation was carried out under reduced pressure (-0.07 to -0.1 MPa) and a reflux ratio of 5 to 10 to obtain 40,518 parts of a light oil fraction with a distillation range of <170°C and 413,628 parts of a phenol oil fraction with a distillation range of 170 to 230°C.

[0148] Then, 137,876 parts of the 170-230°C phenol oil fraction were added to a high-efficiency distillation tower (with 250 theoretical plates) and subjected to vacuum distillation at -0.08 to -0.09 MPa and a reflux ratio of 10 to 25 to obtain 20,517.5 parts of a 180-190°C phenol / o-cresol phenol oil fraction. Sampling and analysis showed a phenol content of 53.35%, with the phenol content comprising 79.6% phenol, 20.2% o-cresol, and 0.2% others. Simultaneous analysis revealed 1.86% indene, 0.13% nitrogen-containing compounds, and 0.05% sulfide.

[0149] Step 2: Synthesis and separation of 2,6-dimethylphenol, 2,4,6-trimethylphenol, etc.

[0150] 600 parts of a ferroalloy aluminum oxide catalyst (80-120 mesh, with a mass ratio of iron oxide to vanadium pentoxide to acidic alumina of 0.5:1:0.02) prepared by loading ferroalloy aluminum oxide on silica gel and 18 parts of 1.5% palladium carbon (20-40 mesh) were loaded into a fixed bed reactor, and 20517.5 parts of a 180-190°C phenol / o-cresol phenol oil fraction (9571.4 parts of non-phenolic phenol oil, 8713.1 parts of phenol, 221 parts of o-cresol) were added. The mixture of 1.1 parts of phenol, 21.9 parts of other phenols), 17000 parts of methanol and 3700 parts of water (4.69 times and 1.81 times the molar number of phenolic materials in the phenol / o-cresol oil fraction, respectively) was injected into the reactor through the preheater by a plunger metering pump, and 14500 parts of quantitative hydrogen (the amount of hydrogen is 0.71 times the mass of the phenol / o-cresol oil fraction) was uniformly introduced into the fixed-bed reactor. The mixture was stirred at normal pressure, 300°C and a liquid hourly space velocity of 0.9h -1 The reaction was carried out under the conditions of 100% conversion of o-cresol and 0.002% of 2,3,6 / 2,4,6-trimethylcyclohexanol, which were qualified. The condensate was added to the still of the rectification kettle (theoretical plate number is about 250) with a reflux ratio of 0.1-2 and the solvent was removed under normal pressure to obtain 8990.9 parts of methanol and 687.3 parts of water, which were applied to the next batch of methylation reaction;

[0151] The remaining material after removing the methanol is then allowed to stand and separate into layers to obtain a water layer and a phenol-containing material layer, respectively. The water layer is extracted with 3,000 parts of phenol / o-cresol dephenolized phenol oil obtained in the previous batch, and separated into layers to obtain an extracted organic phase and an aqueous phase, respectively. The aqueous phase is sent for further treatment; the phenol-containing material layer (organic material layer) and the extracted organic phase (the dephenolized phenol oil solution of phenol obtained by extraction from the water layer) are combined to obtain 26,515.4 parts of a phenol material solution to be distilled (including 12,381.5 parts of dephenolized oil, 8,558.6 parts of 2,6-xylenol, 951.1 parts of 2,4 / 2,5-xylenol, 3,692.6 parts of 2,4,6-trimethylol, 813 parts of 2,3,6-trimethylol, 28.2 parts of 2,3,5-trimethylol, and 90.4 parts of others).

[0152] 26515.4 parts of the above phenolic material solution to be distilled were added to a distillation kettle (theoretical plate number is about 250), and vacuum distilled at -0.085 to -0.09 MPa and a reflux ratio of 10 to 25 to obtain:

[0153] 12380.5 parts of phenol / o-cresol dephenolized phenol oil (analysis of phenol / o-cresol dephenolized phenol oil: indene content 0.15%, nitrogen compound 1.1 ppm, sulfide 0.8 ppm);

[0154] 99.7% 2,6-dimethylphenol 8481.3 parts (nitrogen compound 0.8 ppm, sulfide 0.6 ppm);

[0155] 970 parts of 95.8% 2,4 / 2,5-dimethylphenol (nitrogen compound 0.8 ppm, sulfide 0.7 ppm);

[0156] 99.5% 2,4,6-trimethylphenol 3573.8 parts (nitride 0.7 ppm, sulfide 0.6 ppm);

[0157] 99.7% 2,3,6-trimethylphenol 716.7 parts (nitride 0.7 ppm, sulfide 0.4 ppm);

[0158] 25.3 parts of 99.5% 2,3,5-trimethylphenol (0.6 ppm nitrogen compound, 0.4 ppm sulfide compound).

[0159] Example 3

[0160] A method for separating a phenol / o-cresol phenol oil fraction to obtain dephenolized phenol oil comprises the following steps:

[0161] Step 1: Fraction cutting

[0162] 3,000,000 parts of phenol-containing coal tar from coal pyrolysis of an energy enterprise in Xinjiang were added to the kettle of a distillation tower (100 theoretical plates). First, 15,178 parts of water were removed at -0.05 MPa and a reflux ratio of 0.5 to 5. Then, distillation was carried out under reduced pressure (-0.07 to -0.1 MPa) and a reflux ratio of 5 to 10 to obtain 40,518 parts of a light oil fraction with a distillation range of <170°C and 413,628 parts of a phenol oil fraction with a distillation range of 170 to 230°C.

[0163] Then, 137,876 parts of the 170-230°C phenol oil fraction were added to a high-efficiency distillation tower (with 250 theoretical plates) and subjected to vacuum distillation at -0.08 to -0.09 MPa and a reflux ratio of 10 to 25 to obtain 21,578 parts of a 185-195°C phenol / o-cresol phenol oil fraction. Sampling and analysis showed a phenol content of 58.4%, with the phenol content comprising 18.6% phenol, 64.9% o-cresol, 6.88% 2,6-xylenol, 8.32% m-p-cresol, 0.95% o-ethylphenol, and 0.35% others. Simultaneous analysis revealed 0.72% indene, 0.09% nitrogen-containing compounds, and 0.06% sulfide.

[0164] Step 2: Synthesis and separation of 2,3,6-trimethylphenol and 2,4,6-trimethylphenol:

[0165] 600 parts of the iron vitriol aluminum oxide catalyst prepared by loading the iron vitriol aluminum oxide on silica gel (60-80 mesh, the mass ratio of iron oxide to vanadium pentoxide and acidic alumina is 3:1:0.3) and 20 parts of 1.5% palladium carbon (40-60 mesh) were loaded into a fixed bed reactor, and 21578 parts of the 185-195°C phenol / o-cresol phenol oil fraction (8976.5 parts of dephenolized oil containing non-phenols, 2343.9 parts of phenol, 8178.4 parts of o-cresol, 867.0 parts of 2,6-dimethylphenol, A mixture of 1048.4 parts of m-paracresol, 119.7 parts of o-ethylphenol, 44.1 parts of others), 38,000 parts of methanol and 2,000 parts of water (respectively 9.99 times and 0.94 times the molar number of phenols in the phenol / o-cresol oil fraction) was injected into the reactor through a plunger metering pump via a preheater, and at the same time, 11,000 parts of quantitative hydrogen (0.51 times the amount of hydrogen in the phenol / o-cresol oil fraction) was uniformly introduced into the fixed-bed reactor. The mixture was stirred at normal pressure, 400°C and a liquid hourly space velocity of 0.5h -1 The reaction was carried out under the conditions of 100% conversion of o-cresol and 0.004% of 2,3,6 / 2,4,6-trimethylcyclohexanol, which were qualified. The condensate was added to the still of the rectification kettle (theoretical plate number is about 250) with a reflux ratio of 0.1-2 and the solvent was removed under normal pressure to obtain 28664.2 parts of methanol and 1949 parts of water, which were applied to the next batch of methylation reaction;

[0166] The remaining material after removing the methanol is then allowed to stand for stratification to obtain a water layer and a phenol-containing material layer, respectively. The water layer is extracted with 3,000 parts of phenol / o-cresol dephenolized phenol oil obtained in the previous batch, and separated to obtain an extracted organic phase and an aqueous phase, respectively. The aqueous phase is sent for further treatment; the phenol-containing material layer (organic material layer) and the extracted organic phase (the dephenolized phenol oil solution of phenol obtained by extraction from the water layer) are combined to obtain 28,733.9 parts of phenol material solution to be distilled (including 11,797 parts of dephenolized oil, 13,501.2 parts of 2,4,6-trimethylol, 3,203.9 parts of 2,3,6-trimethylol, 138.9 parts of 2,3,5-trimethylol, and 92.9 parts of others).

[0167] 28733.9 parts of the above phenolic material solution to be rectified were added to a distillation kettle (theoretical plate number is about 250), and vacuum distilled at -0.085 to -0.09 MPa and a reflux ratio of 15 to 30 to obtain:

[0168] 11678.8 parts of phenol / o-cresol dephenolized phenol oil (analysis of phenol / o-cresol dephenolized phenol oil: indene content 0.06%, nitrogen compound 1.0 ppm, sulfide 0.7 ppm);

[0169] 99.2% 2,4,6-trimethylphenol 12807.1 parts (nitride 0.5 ppm, sulfide 0.4 ppm);

[0170] 99.5% 2,3,6-trimethylphenol 2859.3 parts (nitride 0.7 ppm, sulfide 0.5 ppm);

[0171] 99.7% 2,3,5-trimethylphenol 123.8 parts (nitrogen compound 0.8 ppm, sulfide 0.5 ppm).

[0172] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0173] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A method for separating phenol / o-cresol phenol oil fractions to obtain dephenolized phenol oil, characterized in that: The following steps are involved: (1) adding phenol-containing coal tar to a distillation tower, first removing water under reduced pressure, and then fractionating to obtain a slag-free phenol-containing phenol oil with a temperature of ≤300° C.; subjecting the slag-free phenol-containing phenol oil to vacuum distillation to obtain a phenol / o-cresol phenol oil fraction with a distillation range of 180-195° C.; the phenol / o-cresol phenol oil fraction comprises phenolic substances, and the phenolic substances include phenol and o-cresol; (2) loading the catalyst into a reactor, mixing the phenol / o-cresol oil fraction, methanol, and water, and then injecting the mixture into the reactor while introducing hydrogen to carry out the reaction; sampling and analyzing, and removing methanol after the desired requirements are met; (3) the remaining material after methanol removal is allowed to stand for separation to obtain a water layer and a phenol-containing material layer; the water layer is extracted with phenol / o-cresol dephenolized phenol oil, and the layers are separated to obtain an extracted organic phase and an aqueous phase; (4) The phenol-containing material layer is combined with the extracted organic phase, and the combined solution is subjected to vacuum distillation to obtain phenol / o-cresol dephenolized phenol oil, and at least one of 2,6-dimethylphenol, 2,4 / 2,5-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol.

2. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1, wherein: In the step (1), the phenol-containing coal tar includes phenol-containing coal tar obtained by medium-low temperature coal gasification or medium-low temperature coal pyrolysis; And / or, the pressure of the vacuum water removal is -0.01 to -0.07 MPa; the reflux ratio of the vacuum water removal is 0.5 to 5; the number of theoretical plates of the vacuum water removal is 50 to 250; and / or, fractionally distilling to obtain a 170-230° C. deslagging phenol-containing phenol oil; And / or, the number of theoretical plates of the fractional distillation is 50 to 250; and / or, the fractional distillation pressure is -0.07 to -0.1 MPa, and the fractional distillation reflux ratio is 5 to 15; And / or, the number of theoretical plates of the vacuum distillation is 150 to 350; And / or, the pressure of the vacuum distillation is -0.08 to -0.1 MPa, and the reflux ratio of the vacuum distillation is 10 to 30.

3. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1, wherein: In the step (1), the mass content of phenolic substances in the phenol / o-cresol phenol oil fraction is 40-75%; And / or, the mass content of phenol and o-cresol in the phenolic substances is 10 to 100%; And / or, based on mass, the phenolic substances include: 5-95% phenol, 5-90% o-cresol, 0-50% 2,6-dimethylphenol, 0-25% m-cresol, 0-20% p-cresol, and 0-5% o-ethylphenol.

4. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1, wherein: In the step (2), the catalyst comprises an iron sulfate aluminum oxide catalyst and an olefin hydrogenation catalyst; And / or, the reactor includes at least one of a tank reactor, a fixed bed reactor, a fluidized bed reactor, an ebullient bed reactor, and a transport bed reactor.

5. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 4, wherein: In the step (2), the iron vanadium aluminum oxide catalyst comprises iron vanadium aluminum oxide; the iron vanadium aluminum oxide comprises iron oxide, vanadium oxide and aluminum oxide; the mass ratio of the iron oxide, vanadium oxide and aluminum oxide is 0.5-5:1:0.01-0.5; the iron oxide comprises iron oxide, the vanadium oxide comprises vanadium pentoxide, and the aluminum oxide comprises acidic aluminum oxide; And / or, the iron vitriol aluminum oxide catalyst comprises iron vitriol aluminum oxide and a carrier, the carrier comprises silica gel; the mass percentage of the carrier is 10 to 30%; and / or, the particle size of the iron sulfate aluminum oxide catalyst is 50 to 200 mesh; And / or, when the reactor is a tank reactor, the mass of the iron vitriol aluminum oxide catalyst in the catalyst is 5 to 30% of the mass of the phenol / o-cresol phenol oil fraction; And / or, the olefin hydrogenation catalyst comprises at least one of palladium carbon and Raney nickel; the palladium carbon comprises palladium carbon having a palladium element mass percentage of 1 to 5%; And / or, the olefin hydrogenation catalyst comprises a partially deactivated olefin hydrogenation catalyst; and / or, the particle size of the olefin hydrogenation catalyst is 20 to 120 mesh; And / or, in the catalyst, the mass of the olefin hydrogenation catalyst is 0.1 to 5% of the mass of the iron vitriol aluminum oxide catalyst.

6. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1, wherein: In the step (2), the phenol / o-cresol oil fraction is calculated based on the molar number of phenolic substances contained, and the molar ratio of the phenol / o-cresol oil fraction, methanol and water is 1:4-10:0.3-2.0; And / or, the mass of the hydrogen is 0.1 to 3 times the mass of the phenol / o-cresol phenol oil fraction.

7. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1, wherein: In the step (2), the reaction is carried out under normal pressure or pressure; and / or, the reaction temperature is 300-600° C.; And / or, when the reactor is a bed reactor, the liquid hourly space velocity of the reaction is 0.3 to 1.2 h -1 ; And / or, when the reactor is a tank reactor, the reaction pressure is 3 to 9 MPa.

8. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1 or 4, characterized in that: In the step (2), sampling and analysis are performed, and methanol is removed after the required requirements are met; Optionally, achieving the desired requirements includes achieving the desired requirements for o-cresol content and 2,3,6 / 2,4,6-trimethylcyclohexanol content; Optionally, sampling and analysis are performed, and the test results are qualified when the mass content of o-cresol is ≤0.5% and the mass content of 2,3,6 / 2,4,6-trimethylcyclohexanol is ≤0.5%; Optionally, sampling and analysis are performed. When the mass content of 2,3,6 / 2,4,6-trimethylcyclohexanol is ≥1%, the olefin hydrogenation catalyst in the reactor is replaced with a reusable olefin hydrogenation catalyst with lower activity; Optionally, the sampling and analysis is performed by gas chromatography; the gas chromatograph: the detector is a hydrogen flame detector, and the chromatographic column is a chromatographic column specially used for polar phenols; Optionally, methanol is removed by distillation, the number of theoretical plates for distillation is 150 to 350, and the reflux ratio is 0.1 to 2.

9. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1, wherein: In the step (3), the water layer is extracted with phenol / o-cresol dephenolized phenol oil, and the phenol / o-cresol dephenolized phenol oil is 0.1 to 2 times the mass of the water layer material; And / or, the phenol / o-cresol dephenolized phenol oil is the phenol / o-cresol dephenolized phenol oil obtained by the previous batch process; And / or, after separation, the aqueous phase is sent to a post-processing section.

10. The method for obtaining dephenolized phenol oil by separating the phenol / o-cresol phenol oil fraction according to claim 1, characterized in that: In the step (4), the number of theoretical plates of the vacuum distillation is 200 to 300; And / or, the pressure of the vacuum distillation is -0.08 to -0.1 MPa; and / or, the reflux ratio of the vacuum distillation is 10 to 30; And / or, the purity of the 2,6-dimethylphenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and 2,3,5-trimethylphenol is not less than 99% respectively; the purity of the 2,4 / 2,5-dimethylphenol is not less than 95%.