CN108977224B

CN108977224B - Transformer oil base oil and preparation method thereof

Info

Publication number: CN108977224B
Application number: CN201810865649.8A
Authority: CN
Inventors: 单贤根; 舒歌平; 章序文; 杨葛灵; 王洪学; 曹雪萍
Original assignee: China Shenhua Coal to Liquid Chemical Co Ltd; China Energy Investment Corp Ltd; Shanghai Research Institute of China Shenhua Coal to Liquid Chemical Co Ltd
Current assignee: China Shenhua Coal to Liquid Chemical Co Ltd; China Energy Investment Corp Ltd; Shanghai Research Institute of China Shenhua Coal to Liquid Chemical Co Ltd
Priority date: 2018-08-01
Filing date: 2018-08-01
Publication date: 2020-11-03
Anticipated expiration: 2038-08-01
Also published as: CN108977224A

Abstract

The invention provides transformer oil base oil and a preparation method thereof. The preparation method comprises the following steps: 1) fractionating the direct coal liquefaction oil to obtain a diesel oil fraction, wherein the distillation range of the diesel oil fraction is 290-330 ℃; 2) carrying out hydrofining reaction on the diesel oil fraction to obtain a hydrogenation product; 3) carrying out hydrogenation modification reaction on the hydrogenation product to obtain first transformer oil base oil; 4) carrying out hydrogenation complementary refining reaction on the first transformer oil base oil to obtain second transformer oil base oil; the coal directly liquefied oil comprises oil A and oil B, wherein the volume ratio of the oil A to the oil B is 1: 1-1: 10, the oil A and the oil B respectively comprise a certain amount of paraffin, cycloparaffin, monocyclic aromatic hydrocarbon, bicyclic aromatic hydrocarbon and tricyclic aromatic hydrocarbon in percentage by weight, and the sum of the content of each component is equal to 100%. The preparation method has the advantages of short process flow, low energy consumption, high yield of target products and good performance.

Description

Transformer oil base oil and preparation method thereof

Technical Field

The invention relates to the field of petrochemical industry, and particularly relates to transformer oil base oil and a preparation method thereof.

Background

The transformer oil is a liquid insulating material which is used in oil-filled electrical equipment such as transformers, reactors, mutual inductors, sleeves, oil switches and the like and has the functions of insulation, cooling and arc extinction. The main functions of transformer oil include insulation protection, solar heat cooling and arc extinction, and thus the requirements for the electrical and physicochemical properties of transformer oil are particularly high. The cooling heat dispersion, solubility, oxidation resistance, aging resistance, electrical properties, low temperature properties and gassing resistance among the important properties of the transformer oil are closely related to the hydrocarbon composition of the oil.

The transformer oil base oil is a raw material for producing transformer oil. The properties of transformer oils are to a large extent dependent on the properties of the transformer oil base oil. In general, paraffin-based transformer oil base oil has a high pour point, is easy to oxidize to produce a large amount of acidic compounds, has a low aromatic hydrocarbon content, and has some defects in the aspects of the service life of transformer oil, oxidation resistance, gassing resistance and the like. The naphthenic transformer oil base oil has low viscosity at high temperature, excellent dissolving capacity at extremely low temperature, high oxidation stability, excellent electrical characteristics and good heat transfer medium characteristics, can meet the requirements of insulation, cooling and the like of transformer oil, and can stably work for a long time, so the naphthenic transformer oil base oil becomes the well-known optimal raw material for producing the transformer oil base oil. At present, transformer oil produced by naphthenic base oil is adopted by global transformer manufacturers, particularly transformers produced by large-scale multinational companies such as ABB, Alstom and the like without exception.

The raw material of the traditional naphthenic base transformer base oil is naphthenic base crude oil. On the one hand, the reserves of naphthenic base crude oil only account for 2% -3% of the total reserves of crude oil, and the main production places are in the United states, Venezuela and the like. On the other hand, in the main production area of naphthenic base crude oil in China, only Xinjiang krameri keeps stable output of the naphthenic base transformer oil base oil, and other production areas such as Liaohe happy ridge and Bohai Bay cannot be used as stable resources for producing the transformer oil along with output reduction and quality deterioration. With the great development of the power industry in China and the continuous increase of the market demand of the transformer oil in China, the contradiction between supply and demand is more prominent, so that other suitable transformer oil production raw materials are developed, the great localization of the transformer oil is realized, and the practical significance is great.

The direct coal liquefaction technology is taken as an important guarantee of energy in China, the direct coal liquefaction oil product has the characteristics of low sulfur and nitrogen content and high aromatic hydrocarbon content, and how to efficiently carry out comprehensive utilization of the direct coal liquefaction oil is an important link for improving the economy of the direct coal liquefaction oil product according to the product characteristics. The coal direct liquefaction oil can be converted into naphthenic hydrocarbon after hydrotreating and hydro-upgrading.

The preparation method of the transformer oil base oil in the prior art mainly has the following defects:

defect one: long process, high cost, low yield of target product, poor continuity, small treatment capacity and limited resources of naphthenic base distillate oil.

And defect two: and a great deal of environmental pollution (such as acid sludge, nitrogen sludge and white clay sludge) is generated.

For the above reasons, further research on a preparation method of a transformer oil base oil is needed to solve the problems of long process, high cost, low yield of a target product, poor continuity, small treatment amount, limited resources of naphthenic-based distillate oil and generation of a large amount of environmental pollution (such as acid sludge, nitrogen sludge and white clay sludge).

Disclosure of Invention

The invention mainly aims to provide transformer oil base oil and a preparation method thereof, and aims to solve the problems that the preparation method in the prior art is long in process, high in cost, low in target product yield, poor in continuity and small in treatment amount, naphthenic base distillate oil resources are limited, and a large amount of environmental pollution (such as acid sludge, nitrogen slag and white clay slag) is generated.

In order to achieve the above object, according to an aspect of the present invention, there is provided a method for preparing a transformer oil base oil, the method comprising: 1) fractionating the direct coal liquefaction oil to obtain a diesel fraction, wherein the distillation range of the diesel fraction is 290-330 ℃; 2) carrying out hydrofining reaction on the diesel oil fraction to obtain a hydrogenation product; 3) carrying out hydrogenation modification reaction on the hydrogenation product to obtain first transformer oil base oil; 4) carrying out hydrogenation complementary refining reaction on the first transformer oil base oil to obtain second transformer oil base oil; the direct coal liquefaction oil comprises oil A and oil B, wherein the volume ratio of the oil A to the oil B is 1: 1-1: 10, the oil A comprises 5-15 wt% of paraffin, 25-35 wt% of naphthene, 50-60 wt% of monocyclic aromatic hydrocarbon, 10-20 wt% of bicyclic aromatic hydrocarbon and 0-10 wt% of tricyclic aromatic hydrocarbon, and the sum of the contents of the components is equal to 100%, the oil B comprises 0-15 wt% of paraffin, 5-20 wt% of naphthene, 40-55 wt% of monocyclic aromatic hydrocarbon, 35-50 wt% of bicyclic aromatic hydrocarbon and 5-20 wt% of tricyclic aromatic hydrocarbon, and the sum of the contents of the components is equal to 100%.

Further, the reaction pressure of the hydrorefining reaction in the step 2) is 3.0 to 21.0 MPa.

Further, the reaction pressure of the hydrorefining reaction in the step 2) is 10.0 to 15.0 MPa.

Further, the reaction temperature of the hydrofining reaction in the step 2) is 250-400 ℃.

Further, the reaction temperature of the hydrofining reaction in the step 2) is 300-350 ℃.

Further, the volume ratio of the hydrogen gas of the hydrofining reaction in the step 2) to the diesel oil fraction is 400: 1-2000: 1.

Further, the volume ratio of the hydrogen of the hydrofining reaction in the step 2) to the diesel fraction is 800: 1-1200: 1.

Further, the volume space velocity of the hydrofining reaction in the step 2) is 0.1-2.5 h^-1。

Further, the volume space velocity of the hydrofining reaction in the step 2) is 0.5-1.0 h^-1。

Further, the reaction pressure of the hydro-upgrading reaction in the step 3) is 3.0-21.0 MPa.

Further, the reaction pressure of the hydro-upgrading reaction in the step 3) is 10.0-15.0 MPa.

Further, the reaction temperature of the hydro-upgrading reaction in the step 3) is 250-400 ℃.

Further, the reaction temperature of the hydro-upgrading reaction in the step 3) is 300-340 ℃.

Further, the volume ratio of the hydrogen of the hydro-upgrading reaction in the step 3) to the hydrogenation product is 400: 1-2000: 1.

Further, the volume ratio of the hydrogen of the hydro-upgrading reaction in the step 3) to the hydrogenation product is 800: 1-1200: 1.

Further, the volume space velocity of the hydro-upgrading reaction in the step 3) is 0.1-2.5 h^-1。

Further, the volume space velocity of the hydro-upgrading reaction in the step 3) is 0.8-1.5 h^-1。

Further, the reaction pressure of the hydrofinishing reaction in the step 4) is 3.0-15.0 MPa.

Further, the reaction pressure of the hydrofinishing reaction in the step 4) is 6-15.0 MPa.

Further, the reaction temperature of the hydrofinishing reaction in the step 4) is 140-300 ℃.

Further, the reaction temperature of the hydrofinishing reaction in the step 4) is 160-220 ℃.

Further, the volume ratio of the hydrogen of the hydrofinishing reaction in the step 4) to the first transformer oil base oil is 200: 1-2000: 1.

Further, the volume ratio of the hydrogen of the hydrofinishing reaction in the step 4) to the first transformer oil base oil is 400: 1-1000: 1.

Further, the volume space velocity of the hydrofinishing reaction in the step 4) is 0.1-2.5 h^-1。

Further, the volume space velocity of the hydrofinishing reaction in the step 4) is 0.6-1.5 h^-1。

Further, the volume ratio of the oil A to the oil B is 1: 2-1: 8.

Further, the volume ratio of the oil A to the oil B is 1: 3-1: 7.

Further, the volume ratio of the oil A to the oil B is 1: 4-1: 6.

Further, the volume ratio of the oil a to the oil B was 1: 6.

Further, the oil A comprises 5 to 10 weight percent of alkane, 25 to 30 weight percent of cyclane, 50 to 55 weight percent of monocyclic aromatic hydrocarbon, 10 to 15 weight percent of bicyclic aromatic hydrocarbon and 0 to 5 weight percent of tricyclic aromatic hydrocarbon.

Further, the oil A comprises 5 to 7 weight percent of alkane, 28 to 30 weight percent of cyclane, 50 to 55 weight percent of monocyclic aromatic hydrocarbon, 10 to 15 weight percent of bicyclic aromatic hydrocarbon and 0 to 2 weight percent of tricyclic aromatic hydrocarbon.

Further, the oil B comprises 0 to 10 weight percent of alkane, 5 to 15 weight percent of cyclane, 40 to 50 weight percent of monocyclic aromatic hydrocarbon, 35 to 45 weight percent of bicyclic aromatic hydrocarbon and 5 to 15 weight percent of tricyclic aromatic hydrocarbon.

Further, the oil B comprises 0 to 5 weight percent of alkane, 5 to 10 weight percent of cycloalkane, 40 to 45 weight percent of monocyclic aromatic hydrocarbon, 35 to 40 weight percent of bicyclic aromatic hydrocarbon and 5 to 10 weight percent of tricyclic aromatic hydrocarbon.

Further, in step 2), a hydrogenation protection catalyst and a hydrorefining catalyst are used.

Further, in the step 2), the loading volume ratio of the hydrogenation protection catalyst to the hydrofining catalyst is 1: 2-1: 6.

Further, in step 2), the packing volume ratio of the hydrogenation protection catalyst to the hydrorefining catalyst is 1: 4.

Further, in step 2), the hydrogenation protection catalyst is an RGC-1 series hydrogenation protection catalyst and/or an FZC series hydrogenation protection catalyst.

Further, in step 2), the hydrogenation protection catalyst is a catalyst which takes porous refractory inorganic oxide such as alumina as a carrier, takes oxides of metals of group VIB and/or group VIII such as W, Mo, Co and Ni as active components, and optionally contains P, Si, F and B.

Further, in step 2), the hydrofining catalyst is an RNC-2 series hydrofining catalyst and/or an FF-26 series hydrofining catalyst.

Further, in step 2), the active component of the hydrofinishing catalyst is an oxide of a group VIB and/or group VIII metal, such as W, Mo, Co, Ni.

Further, in the step 2), the hydrofining catalyst contains 15-30 wt% of group VIB metal oxide.

Further, in the step 2), the hydrofining catalyst contains 2-6 wt% of VIII group metal oxide.

Further, in the step 2), the specific surface area of the hydrorefining catalyst is not less than 100m²/g。

Further, in step 2), the pore volume of the hydrorefining catalyst is 0.24ml/g or more.

Further, in step 3), a hydro-upgrading catalyst is used.

Further, in step 3), the hydro-upgrading catalyst is an RCC-1 series hydro-upgrading catalyst and/or an FC-28 series hydro-upgrading catalyst.

Further, in step 3), the active component of the hydro-upgrading catalyst is an oxide of a group VIB and/or group VIII metal, such as W, Mo, Co, Ni.

Further, in the step 3), the hydrofining catalyst contains 10-30 wt% of group VIB metal oxide.

Further, in the step 3), the hydrofining catalyst contains 4-10 wt% of VIII group metal oxide.

Further, in the step 3), the specific surface area of the hydro-upgrading catalyst is more than or equal to 200m²/g。

Further, in the step 3), the pore volume of the hydro-upgrading catalyst is 0.2-0.7 mL/g.

Further, in the step 3), the pore volume of the hydro-upgrading catalyst with the pore diameter of 3-10 nm accounts for 70-95% of the total pore volume.

Further, in the step 3), the pore volume of the hydro-upgrading catalyst with the pore diameter of 3-10 nm accounts for 85% -95% of the total pore volume.

Further, in the step 3), the infrared acidity of the hydro-upgrading catalyst is 0.2-0.6 mmol/g.

Further, in step 4), a hydrofinishing catalyst is used.

Further, in the step 4), the hydrofinishing catalyst is an RLF-20 series hydrofinishing catalyst and/or an FMTA-2 series hydrofinishing catalyst.

Further, in step 4), the active component of the hydrofinishing catalyst is an oxide of a group VIII metal such as Pd, Pt.

Further, in step 4), the hydrofinishing catalyst comprises 0.1 to 2% by weight of a group VIII metal oxide.

Further, in the step 4), the hydrofinishing catalyst comprises 0.1-0.8% of Pd oxide and 0.1-0.5% of Pt oxide by weight percentage.

Further, in the step 4), the specific surface area of the hydrofinishing catalyst is not less than 200m²/g。

Further, in step 4), the pore volume of the hydrofinishing catalyst is not less than 0.5 mL/g.

Further, in the step 4), the pore diameter of the hydrofinishing catalyst is not less than 8 nm.

Further, in step 4), the active metal H of the hydrofinishing catalyst₂The adsorption capacity is more than or equal to 80 mL/g.

According to another aspect of the present invention, there is provided a transformer oil base oil prepared by the above preparation method.

By applying the technical scheme of the invention, the preparation method of the transformer oil base oil comprises the following steps: 1) fractionating the direct coal liquefaction oil to obtain a diesel fraction, wherein the distillation range of the diesel fraction is 290-330 ℃; 2) carrying out hydrofining reaction on the diesel oil fraction to obtain a hydrogenation product; 3) carrying out hydrogenation modification reaction on the hydrogenation product to obtain first transformer oil base oil; 4) carrying out hydrogenation complementary refining reaction on the first transformer oil base oil to obtain second transformer oil base oil; the direct coal liquefaction oil comprises oil A and oil B, wherein the volume ratio of the oil A to the oil B is 1: 1-1: 10, the oil A comprises 5-15 wt% of paraffin, 25-35 wt% of naphthene, 50-60 wt% of monocyclic aromatic hydrocarbon, 10-20 wt% of bicyclic aromatic hydrocarbon and 0-10 wt% of tricyclic aromatic hydrocarbon, and the sum of the contents of the components is equal to 100%, the oil B comprises 0-15 wt% of paraffin, 5-20 wt% of naphthene, 40-55 wt% of monocyclic aromatic hydrocarbon, 35-50 wt% of bicyclic aromatic hydrocarbon and 5-20 wt% of tricyclic aromatic hydrocarbon, and the sum of the contents of the components is equal to 100%. The preparation method has the advantages of short process flow, low energy consumption and high yield of target products, the physical properties of the obtained transformer oil base oil meet the transformer oil standard, and the electrical property, the oxidation stability and the gassing resistance of the obtained transformer oil base oil are all good.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

Fig. 1 shows a schematic process flow diagram of the process for producing the naphthenic transformer oil base oil by using the coal direct liquefaction oil.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

As described in the background art, the existing methods for preparing the base oil of transformer oil cannot solve the problems of long process, high cost, low yield of target products, poor continuity, small treatment amount, limited resources of naphthenic base distillate oil and large amount of environmental pollution (such as acid sludge, nitrogen sludge and white clay sludge). In order to solve the above problems, the present invention provides a method for preparing a transformer oil base oil, comprising: 1) fractionating the direct coal liquefaction oil to obtain a diesel fraction, wherein the distillation range of the diesel fraction is 290-330 ℃; 2) carrying out hydrofining reaction on the diesel oil fraction to obtain a hydrogenation product; 3) carrying out hydrogenation modification reaction on the hydrogenation product to obtain first transformer oil base oil; 4) carrying out hydrogenation complementary refining reaction on the first transformer oil base oil to obtain second transformer oil base oil; the direct coal liquefaction oil comprises oil A and oil B, wherein the volume ratio of the oil A to the oil B is 1: 1-1: 10, the oil A comprises 5-15 wt% of paraffin, 25-35 wt% of naphthene, 50-60 wt% of monocyclic aromatic hydrocarbon, 10-20 wt% of bicyclic aromatic hydrocarbon and 0-10 wt% of tricyclic aromatic hydrocarbon, and the sum of the contents of the components is equal to 100%, the oil B comprises 0-15 wt% of paraffin, 5-20 wt% of naphthene, 40-55 wt% of monocyclic aromatic hydrocarbon, 35-50 wt% of bicyclic aromatic hydrocarbon and 5-20 wt% of tricyclic aromatic hydrocarbon, and the sum of the contents of the components is equal to 100%.

In the method, the coal direct liquefaction oil obtained in the step 1) can be used as a gasoline blending component at the temperature of less than 160 ℃, can be used as a diesel blending component at the temperature of 160-290 ℃, and can be used as raw oil for processing other lubricating oil base oil such as refrigerator oil and rubber filling oil at the temperature of more than 330 ℃.

The preparation method has the advantages of short process flow, low energy consumption and high yield of target products, the physical properties of the obtained transformer oil base oil meet the transformer oil standard, and the electrical property, the oxidation stability and the gassing resistance of the obtained transformer oil base oil are all good.

Specifically, compared with the prior art, the preparation method of the invention has the following advantages:

(1) the invention produces the transformer oil base oil by taking the direct coal liquefaction oil as the raw material for the first time, opens up a new way for the quality improvement and utilization of the direct liquefaction oil, and effectively prolongs the industrial chain for the utilization of the direct liquefaction oil. The direct coal liquefaction process is a pyrolysis hydrogenation process, and the produced liquefied oil is subjected to a hydrotreating process, so that the oil product has the characteristics of relative cleanness and low content of metal impurities and water, and is suitable for processing of downstream base oil. Therefore, the method for producing the transformer oil base oil by using the direct coal liquefaction oil has the advantages of short process flow, low energy consumption, good product quality and high target product yield.

(2) The invention firstly carries out hydrotreating on the coal direct liquefaction oil distillate (290 ℃ C. and 330 ℃ C.), and can realize desulfurization, denitrification and partial saturation of aromatic hydrocarbon through hydrofining. Meanwhile, through hydrogenation modification, saturated ring opening is carried out on the two-ring aromatic hydrocarbon and a small amount of tricyclic aromatic hydrocarbon, meanwhile, the completeness of a side chain after ring opening is kept, the two-ring aromatic hydrocarbon is changed into single-ring or two-ring aromatic hydrocarbon with a long side chain, and after hydrogenation modification and hydrogenation complementary refining, a large amount of cyclane with multiple side chains is generated, so that the transformer oil base oil with excellent electrical performance, oxidation stability and gassing resistance can be obtained. Meanwhile, a small amount of straight-chain alkane which has certain influence on the condensation point is isomerized into branched-chain alkane, so that the low-temperature performance of the product is ensured.

(3) The method provides a processing method for improving the economical efficiency of the direct coal liquefaction oil, and develops a new raw material for the production of the base oil of the transformer oil. The energy structure of China is rich in coal and oil, the direct coal liquefaction is used as an important supplementary means of the energy safety guarantee strategy of China, the industrial scale is formed, and the direct coal liquefaction oil is rich in aromatic hydrocarbon and naphthenic hydrocarbon, so that the method can replace the scarce naphthenic base crude oil resource, produce high-quality transformer oil base oil urgently needed by the power industry of China, and simultaneously can effectively promote the reasonable utilization of the direct coal liquefaction oil.

(4) Other fractions after the hydrotreatment by the method can be used as blending components of gasoline and diesel oil or raw materials of other special oil products.

In a preferred embodiment, the reaction pressure of the hydrofinishing reaction in step 2) is 3.0 to 21.0MPa, preferably 10.0 to 15.0 MPa; the reaction temperature is 250-400 ℃, preferably 300-350 ℃; the volume ratio of the hydrogen to the diesel oil fraction is 400: 1-2000: 1, preferably 800: 1-1200: 1; the volume space velocity is 0.1-2.5 h^-1Preferably 0.5 to 1.0h^-1. The reaction conditions of the above-described hydrofining reaction used in the present application can more effectively convert coal into liquid than other reaction conditions of the hydrofining reactionHarmful impurities such as sulfur, oxygen, nitrogen and the like in the coal liquefaction oil are converted into corresponding hydrogen sulfide, water and ammonia to be removed, and olefin and diene are subjected to hydrogenation saturation and aromatic hydrocarbon is subjected to partial hydrogenation saturation, so that the quality of the coal direct liquefaction oil is better improved.

In a preferred embodiment, the reaction pressure of the hydro-upgrading reaction in step 3) is 3.0 to 21.0MPa, preferably 10.0 to 15.0 MPa; the reaction temperature is 250-400 ℃, preferably 300-340 ℃; the volume ratio of the hydrogen to the hydrogenation product is 400: 1-2000: 1, preferably 800: 1-1200: 1; the volume space velocity is 0.1-2.5 h^-1Preferably 0.8 to 1.5h^-1. Compared with other reaction conditions of the hydro-upgrading reaction, the reaction conditions of the hydro-upgrading reaction used in the application can better improve the cetane number of the coal direct liquefaction oil and reduce the condensation point and density of the coal direct liquefaction oil.

In a preferred embodiment, the reaction pressure of the hydrofinishing reaction in step 4) is 3.0 to 15.0MPa, preferably 6 to 15.0 MPa; the reaction temperature is 140-300 ℃, preferably 160-220 ℃; the volume ratio of the hydrogen to the first transformer oil base oil is 200: 1-2000: 1, preferably 400: 1-1000: 1; the volume space velocity is 0.1-2.5 h^-1Preferably 0.6 to 1.5h^-1. Compared with other reaction conditions of the hydrofinishing reaction, the reaction conditions of the hydrofinishing reaction used in the application can better enable the content of the polycyclic aromatic hydrocarbon to be obviously reduced, and can obviously improve the electrical performance.

To further balance the effect between the components, in a preferred embodiment the volume ratio of the oil a and the oil B is 1:2 to 1:8, preferably 1:3 to 1:7, preferably 1:4 to 1:6, preferably 1: 6; preferably the oil A comprises 5-10% by weight of paraffins, 25-30% of naphthenes, 50-55% of mono-cyclic aromatics, 10-15% of bi-cyclic aromatics, 0-5% of tri-cyclic aromatics, preferably the oil A comprises 5-7% by weight of paraffins, 28-30% of naphthenes, 50-55% of mono-cyclic aromatics, 10-15% of bi-cyclic aromatics, 0-2% of tri-cyclic aromatics, preferably the oil B comprises 0-10% by weight of paraffins, 5-15% of naphthenes, 40-50% of mono-cyclic aromatics, 35-45% of bi-cyclic aromatics, 5-15% of tri-cyclic aromatics, preferably the oil B comprises 0-5% by weight of paraffins, 5-10% of naphthenes, 40-45% of mono-cyclic aromatics, 35-40% of bi-cyclic aromatics, 5 to 10 percent of tricyclic aromatic hydrocarbon.

In a preferred embodiment, in step 2), a hydrogenation protection catalyst and a hydrofinishing catalyst are used; preferably, the loading volume ratio of the hydrogenation protection catalyst to the hydrofining catalyst is 1: 2-1: 6, preferably 1: 4. Compared with the filling volume ratio of other hydrogenation protection catalysts and hydrofining catalysts, the filling volume ratio of the hydrogenation protection catalysts and the hydrofining catalysts used in the application can effectively remove impurities, and the quality of the direct coal liquefaction oil is better improved.

In a preferred embodiment, in step 2), the hydrogenation protection catalyst is an RGC-1 series hydrogenation protection catalyst developed by petrochemical Research Institute (RIPP) and/or an FZC series hydrogenation protection catalyst developed by Fushun petrochemical research institute (FRIPP); preferably, the hydrogenation protection catalyst is a catalyst which takes porous refractory inorganic oxide such as alumina as a carrier, takes oxides of metals of VIB group and/or VIII group such as W, Mo, Co and Ni as active components, and optionally contains P, Si, F and B. Compared with other hydrogenation protection catalysts, the hydrogenation protection catalyst used in the application can effectively filter impurities and salts, effectively adsorb substances harmful to the main catalyst in the raw materials, such as heavy metals, and avoid the permanent inactivation of the main catalyst.

In a preferred embodiment, in step 2), the hydrofining catalyst is an RNC-2 series hydrofining catalyst developed by the petrochemical Research Institute (RIPP) and/or an FF-26 series hydrofining catalyst developed by the Fushun petrochemical research institute (FRIPP); preferably the active component of the hydrofinishing catalyst is an oxide of a group VIB and/or group VIII metal, such as W, Mo, Co, Ni; preferably, the hydrofining catalyst comprises 15-30 wt% of group VIB metal oxide; preferably in weight percentThe hydrorefining catalyst comprises 2-6% of a group VIII metal oxide; preferably, the specific surface area of the hydrofining catalyst is more than or equal to 100m²(ii)/g; preferably the pore volume of the hydrofinishing catalyst is 0.24ml/g or more. Compared with other hydrofining catalysts, the hydrofining catalyst used in the application can more effectively convert harmful impurities such as sulfur, oxygen, nitrogen and the like in the direct coal liquefaction oil into corresponding hydrogen sulfide, water and ammonia for removal, and enables olefin and diene to be subjected to hydrogenation saturation and aromatic hydrocarbon to be subjected to partial hydrogenation saturation, so that the quality of the direct coal liquefaction oil is better improved.

In a preferred embodiment, in step 3), a hydro-upgrading catalyst is used; preferably, the hydro-upgrading catalyst is RCC-1 series hydro-upgrading catalyst developed and produced by petrochemical Research Institute (RIPP) or FC-28 series hydro-upgrading catalyst developed and produced by Fushun petrochemical research institute (FRIPP); preferably, the active component of the hydro-upgrading catalyst is an oxide of a group VIB and/or group VIII metal, such as W, Mo, Co, Ni; preferably, the hydrofining catalyst comprises 10-30 wt% of group VIB metal oxide; preferably the hydrofinishing catalyst comprises 4-10% by weight of a group VIII metal oxide; preferably, the specific surface area of the hydro-upgrading catalyst is more than or equal to 200m²(ii)/g; preferably, the pore volume of the hydro-upgrading catalyst is 0.2-0.7 mL/g; preferably, the pore volume of the hydro-upgrading catalyst with the pore diameter of 3-10 nm accounts for 70-95% of the total pore volume; preferably, the pore volume of the hydro-upgrading catalyst with the pore diameter of 3-10 nm accounts for 85% -95% of the total pore volume; preferably, the infrared acidity of the hydro-upgrading catalyst is 0.2-0.6 mmol/g. Compared with other hydrogenation modification catalysts, the hydrogenation modification catalyst used in the application can better improve the cetane number of the coal direct liquefaction oil and reduce the condensation point and density of the coal direct liquefaction oil.

In a preferred embodiment, in step 4), a hydrofinishing catalyst is used; preferably, the hydrofinishing catalyst is RLF-20 series hydrofinishing catalyst developed and produced by petrochemical Research Institute (RIPP) and/or developed and produced by compliant petrochemical research institute (FRIPP)FMTA-2 series hydrofinishing catalyst; preferably the active component of the hydrofinishing catalyst is an oxide of a group VIII metal such as Pd, Pt; preferably the hydrofinishing catalyst comprises 0.1 to 2% by weight of a group VIII metal oxide; preferably the hydrofinishing catalyst comprises 0.1-0.8% by weight of Pd oxide and 0.1-0.5% by weight of Pt oxide; preferably, the specific surface area of the hydrofinishing catalyst is more than or equal to 200m²(ii)/g; preferably, the pore volume of the hydrofinishing catalyst is more than or equal to 0.5 mL/g; preferably, the pore diameter of the hydrofinishing catalyst is more than or equal to 8 nm; preferably the active metal H of the hydrofinishing catalyst₂The adsorption capacity is more than or equal to 80 mL/g. Compared with other hydrofinishing catalysts, the hydrofinishing catalyst used in the application can obviously reduce the content of polycyclic aromatic hydrocarbon and obviously improve the electrical performance.

The process flow diagram of the preparation method of the invention can be shown in fig. 1, wherein the coal direct liquefaction oil 1 enters a fractionating tower 2 to respectively obtain a fraction 3 at a temperature of less than 160 ℃, a fraction 4 at a temperature of 160-290 ℃, a fraction 5 at a temperature of 290-330 ℃ and a fraction 6 at a temperature of more than 330 ℃. Wherein the fraction 3 at the temperature of less than 160 ℃ can be used as a gasoline blending component, the fraction 4 at the temperature of 160-290 ℃ can be used as a diesel blending component, and the fraction 6 at the temperature of more than 330 ℃ can be further cut into a refrigerator oil base oil raw material, a rubber filling oil raw material or an environment-friendly aromatic oil raw material. And (3) allowing the 290-330 ℃ fraction 5 to enter a hydrofining reaction zone 7, and in the presence of hydrogen 8, contacting with a hydrofining catalyst to perform desulfurization, denitrification and deep saturation reaction of aromatic hydrocarbon, so that the content of the aromatic hydrocarbon is reduced, and the oxidation stability index of the product is ensured. The hydrorefining reaction product 9 enters a hydroupgrading reaction zone 10, and the saturated ring opening is carried out on the two-ring and a small amount of tricyclic aromatic hydrocarbon, and meanwhile, the completeness of the side chain after the ring opening is kept, so that the ring-opened polycyclic aromatic hydrocarbon is changed into monocyclic or bicyclic aromatic hydrocarbon with multiple side chains. Then, after the hydro-upgrading product 11 is separated into gas 13 by a separator 12, the liquid phase product 14 enters a hydro-supplementation refining reactor 16 and is further saturated with aromatic hydrocarbon after being mixed with hydrogen 15, the content of aromatic hydrocarbon above three rings is reduced, the supplementation refining product 17 enters a fractionating tower 18 to separate a small amount of by-products 19 and tail gas 24, and the liquid phase product 20 enters a pressure reducing tower 21 to separate a small amount of by-products 22, so that a transformer oil base oil product 23 is obtained.

In addition, according to another aspect of the present invention, there is provided a transformer oil base oil prepared by the above preparation method.

The physical properties of the transformer oil base oil prepared by the preparation method meet the transformer oil standard, and the electrical property, the oxidation stability and the gassing resistance of the transformer oil base oil are all good.

The beneficial effects of the present invention are further illustrated by the following examples:

the various catalysts referred to in the examples may be selected from commercial catalysts by nature, or may be prepared as known in the art. The hydrogenation protective agent in the hydrogenation treatment process can be selected from commercial catalysts such as RGC-1 series hydrogenation protective agents developed and produced by petrochemical research institute; the hydrofining catalyst can be selected from commercial catalysts such as RNC-2 series hydrofining catalysts developed and produced by petrochemical research institute; the hydrogenation modification catalyst can be selected from commercial catalysts such as RCC-1 series commercial hydrogenation modification catalysts developed and produced by petrochemical research institute; the hydrogenation complementary refining catalyst is RLF-20 series commercial hydrogenation complementary refining catalyst developed and produced by petrochemical research institute.

Example 1

The Shenhua direct coal liquefaction oil is used as a raw material (the coal direct liquefaction oil is prepared by mixing medium-temperature oil and high-temperature oil according to a ratio of 1: 6), and the specific properties of the medium-temperature oil and the high-temperature oil are shown in Table 1. The hydrogenation refining reaction area is filled with a hydrogenation protection catalyst RGC-1 and a hydrogenation refining catalyst RNC-2, and the filling volume ratio of the hydrogenation protection catalyst RGC-1 to the hydrogenation refining catalyst RNC-2 is 1: 4. The hydrogenation modification reaction zone is filled with a hydrogenation modification catalyst RCC-1. The hydrogenation refining reaction area is filled with a hydrogenation refining catalyst RLF-20. The process conditions and product properties of the hydrogenation process are shown in tables 2 and 3.

Example 2

The Shenhua coal direct liquefaction oil is used as a raw material (the coal direct liquefaction oil is prepared by mixing medium-temperature oil and high-temperature oil according to a ratio of 1: 1), the rest is the same as the example 1, and the process conditions and the product properties of the hydrogenation process are shown in tables 2 and 3.

Example 3

The Shenhua coal direct liquefaction oil is used as a raw material (the coal direct liquefaction oil is prepared by mixing medium-temperature oil and high-temperature oil according to a ratio of 1: 10), the rest is the same as the example 1, and the process conditions and the product properties of the hydrogenation process are shown in tables 2 and 3.

Example 4

The hydrogenation reaction zone was filled with a hydrogenation protection catalyst FZC and a hydrogenation refining catalyst FF-26, the filling volume ratio of the hydrogenation protection catalyst RGC-1 to the hydrogenation refining catalyst RNC-2 was 1:6, the rest was the same as in example 1, and the process conditions and product properties in the hydrogenation process are shown in tables 2 and 3.

Example 5

The hydrogenation modification reaction zone was filled with a hydrogenation modification catalyst FC-28, the rest was the same as in example 1, and the process conditions and product properties during hydrogenation are shown in tables 2 and 3.

Example 6

The hydrorefining reaction zone was filled with a hydrorefining catalyst FMTA-2, the rest was the same as in example 1, and the process conditions and product properties during the hydrogenation process are shown in tables 2 and 3.

Comparative example 1

The same feed as in example 1 was used except that the hydrorefined product was not subjected to hydro-upgrading, and the process conditions and product properties during hydrogenation are shown in tables 2 and 3.

Comparative example 2

The same raw materials as in example 1 were used except that the hydroupgraded product was not subjected to hydrorefining, and the process conditions and product properties during the hydrogenation process are shown in tables 2 and 3.

TABLE 1 direct coal liquefaction oil Properties

TABLE 2 Process conditions of examples and comparative examples

Experiment number	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2
						Hydrorefining process conditions
Reaction temperature of	350	350	350	350	350
						Reaction pressure, MPa	15	15	15	15	15
Volume ratio of hydrogen to oil	1000：1	1000：1	1000：1	1000：1	1000：1
						Volumetric space velocity h^-1	0.6	0.6	0.6	0.6	0.6
Hydro-upgrading process conditions
						Reaction temperature of	320	320	320		320
Reaction pressure, MPa	15	15	15		15
						Volume ratio of hydrogen to oil	1000：1	1000：1	1000：1		1000：1
Volumetric space velocity h^-1	1	1	1		1
						Hydrofinishing process conditions
Reaction temperature of	180	180	180	180
						Reaction pressure, MPa	15	15	15	15
Volume ratio of hydrogen to oil	400：1	400：1	400：1	400：1
						Volumetric space velocity h^-1	1	1	1	1
Yield of the target product, wt%	85.2	85.2	85.2	92.1	87.1

TABLE 3 Properties of the product

From examples 1 to 6, it can be seen that the physical properties of the transformer oil base oil obtained by the processing technology of hydrofining, hydroupgrading and hydrorefining of the direct coal liquefaction oil meet the transformer oil standards, and the indexes are better, which indicates that the process for processing the transformer oil base oil by the direct coal liquefaction oil provided by the invention is feasible.

It can be seen from the product properties of examples 1-6 and comparative example 1 that the transformer oil base oil product obtained by only hydrofining the coal-directly liquefied oil without hydro-upgrading process has slightly good gassing resistance, but poor oxidation stability, poor electrical properties (high dielectric loss factor, low breakdown voltage), and poor low temperature performance (-38 ℃), and is not qualified.

As can be seen from the product properties of the examples 1 to 6 and the comparative example 2, the transformer oil obtained by performing three-stage hydrogenation on the direct coal liquefaction oil through hydrofining, hydrogenation modification and hydrogenation complementary refining is obviously reduced in content compared with the fused ring aromatic hydrocarbon in the comparative example 2, and the electrical performance is improved to a certain extent.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of transformer oil base oil is characterized by comprising the following steps:

1) fractionating the coal direct liquefaction oil to obtain a diesel fraction, wherein the distillation range of the diesel fraction is 290-330 ℃;

2) carrying out hydrofining reaction on the diesel oil fraction to obtain a hydrogenation product;

3) carrying out hydrogenation modification reaction on the hydrogenation product to obtain first transformer oil base oil;

4) carrying out a hydrofinishing reaction on the first transformer oil base oil to obtain second transformer oil base oil;

wherein the coal direct liquefaction oil comprises oil A and oil B, wherein the volume ratio of the oil A to the oil B is 1: 1-1: 10,

wherein the oil A comprises 5 to 15 weight percent of alkane, 25 to 35 weight percent of cycloalkane, 50 to 60 weight percent of monocyclic aromatic hydrocarbon, 10 to 20 weight percent of bicyclic aromatic hydrocarbon and 0 to 10 weight percent of tricyclic aromatic hydrocarbon, the sum of the contents of all the components is equal to 100 percent,

wherein the oil B comprises 0 to 15 weight percent of alkane, 5 to 20 weight percent of cycloalkane, 40 to 55 weight percent of monocyclic aromatic hydrocarbon, 35 to 50 weight percent of bicyclic aromatic hydrocarbon and 5 to 20 weight percent of tricyclic aromatic hydrocarbon, and the sum of the contents of all the components is equal to 100 percent.

2. The production method according to claim 1, wherein the reaction pressure of the hydrorefining reaction in step 2) is 3.0 to 21.0 MPa; the reaction temperature is 250-400 ℃; the volume ratio of the hydrogen to the diesel fraction is 400: 1-2000: 1; the volume space velocity is 0.1-2.5 h^-1。

3. The production method according to claim 1, wherein the reaction pressure of the hydrorefining reaction in step 2) is 10.0 to 15.0 MPa; the reaction temperature is 300-350 ℃; the volume ratio of the hydrogen to the diesel fraction is 800: 1-1200: 1; the volume space velocity is 0.5-1.0 h^-1。

4. The production method according to claim 1, wherein the reaction pressure of the hydro-upgrading reaction in step 3) is 3.0 to 21.0 MPa; the reaction temperature is 250-400 ℃; the volume ratio of the hydrogen to the hydrogenation product is 400: 1-2000: 1; the volume space velocity is 0.1-2.5 h^-1。

5. According to claim 1The preparation method is characterized in that the reaction pressure of the hydro-upgrading reaction in the step 3) is 10.0-15.0 MPa; the reaction temperature is 300-340 ℃; the volume ratio of the hydrogen to the hydrogenation product is 800: 1-1200: 1; the volume space velocity is 0.8-1.5 h^-1。

6. The production method according to claim 1, wherein the reaction pressure of the hydrofinishing reaction in the step 4) is 3.0 to 15.0 MPa; the reaction temperature is 140-300 ℃; the volume ratio of the hydrogen to the first transformer oil base oil is 200: 1-2000: 1; the volume space velocity is 0.1-2.5 h^-1。

7. The production method according to claim 1, wherein the reaction pressure of the hydrofinishing reaction in the step 4) is 6 to 15.0 MPa; the reaction temperature is 160-220 ℃; the volume ratio of the hydrogen to the first transformer oil base oil is 400: 1-1000: 1; the volume space velocity is 0.6-1.5 h^-1。

8. The method according to any one of claims 1 to 7, wherein the volume ratio of the oil A to the oil B is 1:2 to 1: 8.

9. The method according to any one of claims 1 to 7, wherein the volume ratio of the oil A to the oil B is 1:3 to 1: 7.

10. The method according to any one of claims 1 to 7, wherein the volume ratio of the oil A to the oil B is 1:4 to 1: 6.

11. The method according to any one of claims 1 to 7, wherein the volume ratio of the oil A and the oil B is 1: 6.

12. The production method according to any one of claims 1 to 7,

the oil A comprises 5-10% of alkane, 25-30% of cycloalkane, 50-55% of monocyclic aromatic hydrocarbon, 10-15% of bicyclic aromatic hydrocarbon and 0-5% of tricyclic aromatic hydrocarbon in percentage by weight.

13. The production method according to any one of claims 1 to 7,

the oil A comprises 5-7% of alkane, 28-30% of cycloalkane, 50-55% of monocyclic aromatic hydrocarbon, 10-15% of bicyclic aromatic hydrocarbon and 0-2% of tricyclic aromatic hydrocarbon in percentage by weight.

14. The production method according to any one of claims 1 to 7,

the oil B comprises 0-10% of alkane, 5-15% of cycloalkane, 40-50% of monocyclic aromatic hydrocarbon, 35-45% of bicyclic aromatic hydrocarbon and 5-15% of tricyclic aromatic hydrocarbon in percentage by weight.

15. The production method according to any one of claims 1 to 7,

the oil B comprises 0-5% of alkane, 5-10% of cycloalkane, 40-45% of monocyclic aromatic hydrocarbon, 35-40% of bicyclic aromatic hydrocarbon and 5-10% of tricyclic aromatic hydrocarbon in percentage by weight.

16. The production method according to any one of claims 1 to 7, characterized in that, in step 2), a hydrogenation protection catalyst and a hydrofinishing catalyst are used.

17. The preparation method according to claim 16, wherein the loading volume ratio of the hydrogenation protection catalyst to the hydrorefining catalyst is 1:2 to 1: 6.

18. The method of claim 16, wherein the loading volume ratio of the hydrogenation protection catalyst to the hydrofinishing catalyst is 1: 4.

19. The production method according to claim 16, wherein the hydrogenation protection catalyst is an RGC-1 series hydrogenation protection catalyst and/or an FZC series hydrogenation protection catalyst.

20. The preparation method according to claim 16, wherein the hydrogenation protection catalyst is a catalyst comprising a porous refractory inorganic oxide as a carrier, an oxide of a metal of group VIB and/or group VIII as an active component, and optionally P, Si, F, and B.

21. The production method according to claim 16, wherein the hydrofining catalyst is an RNC-2 series hydrofining catalyst and/or an FF-26 series hydrofining catalyst.

22. The process according to claim 16, wherein the active component of the hydrofinishing catalyst is an oxide of a metal of group VIB and/or group VIII.

23. The method of claim 22, wherein the hydrofinishing catalyst comprises 15 to 30 wt% of a group VIB metal oxide.

24. The method of claim 22, wherein the hydrofinishing catalyst comprises 2-6% by weight of a group VIII metal oxide.

25. The production method according to claim 16, wherein the specific surface area of the hydrorefining catalyst is 100m or more²The pore volume is more than or equal to 0.24 ml/g.

26. The production method according to any one of claims 1 to 7, characterized in that, in step 3), a hydro-upgrading catalyst is used.

27. The production method according to claim 26, wherein the hydro-upgrading catalyst is an RCC-1 series hydro-upgrading catalyst and/or an FC-28 series hydro-upgrading catalyst.

28. The preparation method according to claim 26, characterized in that the active component of the hydro-upgrading catalyst is an oxide of a group VIB and/or group VIII metal.

29. The method of claim 28, wherein the hydro-upgrading catalyst comprises 10 to 30 wt% of a group VIB metal oxide.

30. The method of claim 28, wherein the hydro-upgrading catalyst comprises 4 to 10 wt% of a group VIII metal oxide.

31. The preparation method according to claim 26, wherein the specific surface area of the hydro-upgrading catalyst is not less than 200m²The pore volume is 0.2-0.7 mL/g, the pore volume with the pore diameter of 3-10 nm accounts for 70-95% of the total pore volume, and the infrared acidity is 0.2-0.6 mmol/g.

32. The preparation method of claim 31, wherein the pore volume of the hydro-upgrading catalyst with a pore diameter of 3-10 nm accounts for 85-95% of the total pore volume.

33. The production method according to any one of claims 1 to 7, characterized in that, in step 4), a hydrofinishing catalyst is used.

34. The method of claim 33, wherein the hydrofinishing catalyst is an RLF-20 series hydrofinishing catalyst and/or an FMTA-2 series hydrofinishing catalyst.

35. The method of claim 33, wherein the active component of the hydrofinishing catalyst is an oxide of a group VIII metal.

36. The method of claim 35, wherein the hydrofinishing catalyst comprises 0.1-2% by weight of a group VIII metal oxide.

37. The method of claim 35, wherein the hydrofinishing catalyst comprises, in weight percent, 0.1% to 0.8% Pd oxide and 0.1% to 0.5% Pt oxide.

38. The method according to claim 35, wherein the specific surface area of the hydrofinishing catalyst is 200m or more²The pore volume is more than or equal to 0.5mL/g, the pore diameter is more than or equal to 8nm, and the active metal H₂The adsorption capacity is more than or equal to 80 mL/g.

39. A transformer oil base oil prepared by the method of any one of claims 1 to 38.