CN115386395B - Method for reducing cloud point of Fischer-Tropsch synthetic oil, complexing agent and application of complexing agent - Google Patents

Abstract

The invention relates to the technical field of Fischer-Tropsch synthesis oil dewaxing processes, and discloses a method for reducing the cloud point of Fischer-Tropsch synthesis oil and application of a complexing agent and the complexing agent. The complexing agent comprises a component A and a component B, wherein the component A is at least one of cellulose, glucose, urea, thiourea, acetamide and propionamide, and the component B is at least one of diatomite, clay, kaolin, titanium pigment and pseudo-boehmite; wherein, the component A: the mass ratio of the component B is (1-50): 1. the dewaxing method has the advantages of high dewaxing efficiency, no need of using an activating agent and a solvent, simple process and easy realization, and can obviously reduce the cloud point of Fischer-Tropsch synthetic oil and improve the low-temperature flow property.

Description

Method for reducing cloud point of Fischer-Tropsch synthetic oil and complexing agent and application of complexing agent

Technical Field

The invention relates to the technical field of Fischer-Tropsch synthetic oil dewaxing process, and in particular to a method for reducing the cloud point of Fischer-Tropsch synthetic oil, a complexing agent and the application of the complexing agent.

Background technique

For oil products prepared by the Fischer-Tropsch synthesis process, the content of straight-chain hydrocarbons is usually more than 90%, so it can be used as a raw material for high-quality diesel and lubricant base oil. Since this oil product has the disadvantages of a high pour point and poor low-temperature fluidity, isomerization technology must be used to improve the properties of the oil product. However, after the oil products prepared by the Fischer-Tropsch synthesis process are isomerized, normal alkanes will still remain in the product, resulting in a low drop in the cloud point of the product oil and unsatisfactory low-temperature fluidity. Therefore, it is necessary to dewax it to reduce the cloud point.

CN104560195B discloses a method for dewaxing an isopropanol urea aqueous solution, which comprises: the raw oil and the isopropanol urea aqueous solution are mixed and then enter the reactor for complexation reaction, the reactor is operated under reduced pressure, the gas phase effluent at the top of the reactor is cooled and circulated back to the reactor, a part of the reaction product obtained at the bottom of the reactor is returned to the reactor, and the remaining part is removed from the complex and settled in a washing tower for subsequent separation treatment, wherein the feed temperature of the reactor is 60-80°C, the final reaction temperature is 20-32°C, and the operating pressure of the reactor is 22-50kPa. The method uses isopropanol as a cooling medium, and utilizes the vaporization absorption heat when isopropanol and water form an azeotrope to achieve the multi-temperature requirements of the complexation reaction, but the reactor needs to be decompressed.

CN102453548B discloses a solvent dewaxing method using a dewaxing aid, the method comprising: mixing a molten dewaxing raw material and a dewaxing aid, then adding a dewaxing solvent and cooling to a dewaxing temperature, the solvent is added by a multi-point dilution method, or a one-time full dilution method, filtering and separating at the dewaxing temperature to obtain dewaxed oil and dewaxed wax paste, the dewaxing aid being any fraction of Fischer-Tropsch wax greater than 530°C. The solvent can be a C3-C6 fatty ketone or a mixture thereof, or a mixture of a ketone and a C6-C8 aromatic hydrocarbon. The method can increase the filtering speed, but involves the use of an auxiliary agent and ketone and aromatic hydrocarbon solvents.

CN101191083B discloses a method for reducing the cloud point of solvent dewaxed oil, which comprises: a. mixing waxy lubricating oil with dewaxing solvent, cooling to the filtering temperature, and sending to a drum filter for filtering; b. cooling the filtrate obtained in step a to 1°C to 5°C lower than the filtering temperature of the drum filter, and sending to a tubular filter for secondary filtration; sending the filtrate to a separation system to separate the dewaxing solvent from the dewaxing lubricating oil; c. after the differential pressure drop at the inlet and outlet of the tubular filter reaches a set value, stop filtering, rinse with a dewaxing solvent to dissolve the wax crystals thereon, and mix the rinsing liquid with the waxy lubricating oil described in step a. This method requires the use of a dewaxing solvent, has a lengthy process flow, and has specific requirements for the filter.

In summary, the prior art generally requires the introduction of an activator and an organic dewaxing solvent during the dewaxing process, has strict conditions for the reaction or filtration process, requires multiple distillations to remove the solvent and recover it, and has a lengthy process flow, resulting in a long processing cycle and high costs. Therefore, it is of great practical significance to provide a method with high dewaxing efficiency, simple and easy process implementation, and short processing cycle.

Summary of the invention

The purpose of the present invention is to overcome the problem that residual normal alkanes still exist in the oil prepared by the Fischer-Tropsch synthesis process after isomerization treatment, resulting in a high cloud point and poor low-temperature fluidity of the product oil, as well as the problem of complex solvent recovery process and high energy consumption in the existing solvent dewaxing technology. A method for reducing the cloud point of Fischer-Tropsch synthetic oil and a complexing agent and the application of the complexing agent are provided.

In order to achieve the above-mentioned object, the first aspect of the present invention provides a complexing agent for reducing the cloud point of Fischer-Tropsch synthetic oil, the complexing agent comprising component A and component B, the component A is at least one of cellulose, glucose, urea, thiourea, acetamide, and propionamide, and the component B is at least one of diatomaceous earth, white clay, kaolin, titanium dioxide, and pseudo-boehmite; wherein,

The mass ratio of component A:component B is (1-50):1.

A second aspect of the present invention provides a method for reducing the cloud point of Fischer-Tropsch synthetic oil, the method comprising:

(A) subjecting the Fischer-Tropsch synthetic oil to a complexing reaction with a complexing agent to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation to obtain dewaxed oil and wax paste;

Wherein, in step (A), the complexing agent is the complexing agent provided in the first aspect of the present invention.

The third aspect of the present invention provides use of the complexing agent described in the first aspect in reducing the cloud point of Fischer-Tropsch synthetic oil.

Through the above technical solution, the method provided by the present invention has the following beneficial effects:

(1) No activator and solvent are required during the dewaxing process, which avoids the process of multiple solvent recovery, thereby simplifying the process and reducing energy consumption;

(2) Achieve efficient separation of normal paraffins and isoparaffins in the isomerized Fischer-Tropsch oil, with the isoparaffin content in the resulting dewaxed oil exceeding 98 wt%;

(3) The cloud point of Fischer-Tropsch synthetic oil can be significantly reduced. After being treated by the method of the present invention, the cloud point of the obtained dewaxed oil can be reduced to -30°C, and the low-temperature flowability is greatly improved;

(4) It is not only suitable for removing residual normal alkanes in the lubricating oil base oil prepared by isomerization of Fischer-Tropsch oil, but also can effectively reduce the cloud point of diesel and white oil products prepared by Fischer-Tropsch oil.

Detailed ways

The endpoints and any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

The first aspect of the present invention provides a complexing agent for reducing the cloud point of Fischer-Tropsch synthetic oil, the complexing agent comprising component A and component B, the component A is at least one of cellulose, glucose, urea, thiourea, acetamide, and propionamide, and the component B is at least one of diatomaceous earth, white clay, kaolin, titanium dioxide, and pseudo-boehmite; wherein,

The mass ratio of component A:component B is (1-50):1.

In the present invention, the inventors have found that a solid complexing agent comprising component A and component B is used, which can react with residual normal alkanes in isomerized Fischer-Tropsch synthetic oil with high selectivity, and the generated dewaxed oil can be used for subsequent fine processing, and the generated complex product can be heated and decomposed to obtain normal alkanes and solid complexing agents, wherein the normal alkanes can be recovered, and the solid complexing agent can be added to the raw material oil to be treated again for recycling. The solid complexing agent is applied to the complex dewaxing of isomerized Fischer-Tropsch synthetic oil, and the activator and solvent in the conventional dewaxing method are not required, and the lengthy solvent recovery process is avoided. By studying the specific component A, component B and dewaxing process conditions in the complexing agent, the efficient separation of normal alkanes and isoalkanes in the isomerized Fischer-Tropsch synthetic oil can be achieved, and the content of isoalkanes in the obtained dewaxed oil is higher than 98wt%, which greatly reduces the cloud point of the Fischer-Tropsch synthetic oil, and further improves the low-temperature flow performance.

In some embodiments of the present invention, the complexing agent comprises component A and component B, wherein component A is preferably at least one of cellulose, glucose, urea, thiourea, acetamide, and propionamide; component B is preferably at least one of diatomaceous earth, kaolin, kaolin, titanium dioxide, and pseudo-boehmite; and the mass ratio of component A: is (1-50):1.

In the present invention, the complexing agent is solid, and its preparation process may include: (1) crushing the component A to obtain the component A powder, and the particle size of the component A powder is preferably 100-200 mesh; (2) crushing the component B to obtain the component B powder, and the particle size of the component B powder is preferably 80-100 mesh; (3) fully mixing the component A powder with the component B powder, and then kneading and molding to obtain the complexing agent, wherein the mass ratio of the component A to the component B can be (1-50): 1, and the shape of the complexing agent can be one of spherical, clover-shaped, four-leaf clover-shaped and butterfly-shaped. The present invention has no special limitation on the crushing and kneading in the preparation process of the complexing agent, and the conventional crushing and kneading methods in the art can be used.

In the present invention, in order to enable the complexing agent to have a better selective complexing effect on normal alkanes, thereby obtaining a better dewaxing effect, more preferably, the component A is at least one of cellulose, urea, thiourea, and propionamide; the component B is at least one of white clay, kaolin, and titanium dioxide; the mass ratio of the component A:component B can be (2-40):1;

Further preferably, the component A is at least one of urea, propionamide and thiourea, wherein thiourea accounts for 1/2-5/6 of the total mass of the component A; the component B is kaolin and kaolin, wherein kaolin accounts for 1/2-7/8 of the total mass of the component B; the mass ratio of the component A:component B is (15-30):1.

A second aspect of the present invention provides a method for reducing the cloud point of Fischer-Tropsch synthetic oil, the method comprising:

(A) subjecting the Fischer-Tropsch synthetic oil to a complexing reaction with a complexing agent to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation to obtain dewaxed oil and wax paste;

Wherein, in step (A), the complexing agent is the complexing agent provided by the first aspect of the present invention.

In some embodiments of the present invention, the Fischer-Tropsch synthetic oil is a product obtained by isomerizing an oil product prepared by the Fischer-Tropsch synthesis process, and preferably has a cloud point of -30°C to 60°C. The isomerization treatment can adopt a conventional method for isomerizing an oil product prepared by the Fischer-Tropsch synthesis process in the art, for example, in the presence of a catalyst, at least one of the whole fraction of the Fischer-Tropsch hydrofining tail oil, the narrow fraction of the Fischer-Tropsch hydrofining tail oil, and the whole fraction of the Fischer-Tropsch hydrocracking tail oil is isomerized. Wherein, the catalyst includes at least one of ZSM-12, ZSM-22, ZSM-23, ZSM-48, SAPO-11 and a catalyst with mordenite as a carrier.

Preferably, the initial boiling point of the Fischer-Tropsch synthetic oil may be 150-200°C, and the final boiling point may be 650-700°C.

More preferably, the initial distillation point of the Fischer-Tropsch synthetic oil may be 180-200°C, and the final distillation point may be 650-680°C.

In some embodiments of the present invention, in step (A), the complexing reaction preferably involves adding the complexing agent to the Fischer-Tropsch oil for thorough mixing and reaction, wherein the mass ratio of the Fischer-Tropsch oil to the complexing agent may be (50-1):1, preferably (20-1):1.

In the present invention, in step (A), the conditions of the complexation reaction include: the temperature can be -5°C to 100°C, preferably -5°C to 80°C; the time can be 0.5-72h, preferably 1-48h.

Preferably, in order to make the complexation reaction proceed more fully and thus better separate the residual normal alkanes in the Fischer-Tropsch synthetic oil, the conditions of the complexation reaction also include stirring, and the stirring rate can be 30-800 rpm, preferably 100-600 rpm.

In some embodiments of the present invention, in step (B), the first filtration separation can be carried out by conventional filtration separation methods in the art, preferably one of suction filtration, filter pressing and centrifugation. The temperature of the first filtration separation can be -35°C to 100°C.

Preferably, in order to obtain a better filtering and separating effect on the reaction product, the temperature of the first filtering and separating may be -35°C to 60°C.

In the present invention, after the first filtration and separation, the wax paste obtained is a complex reaction product, which is in a white paste state, and its main components include complexed normal alkanes, complexing agents and a small amount of attached isoalkanes; the dewaxed oil obtained is a product, in which the content of isoalkanes is higher than 98wt%, and the content of residual normal alkanes is very low. Compared with the Fischer-Tropsch synthetic oil before treatment by the method of the present invention, the cloud point of the dewaxed oil is greatly reduced, and thus the low-temperature flow performance is greatly improved, which can meet the raw material index requirements as high-quality diesel and lubricant base oil.

In some embodiments of the present invention, preferably, the method for reducing the cloud point of Fischer-Tropsch synthetic oil further comprises: heating and filtering the wax paste successively to obtain normal alkanes and the complexing agent; wherein the complexing agent is returned to step (A) for recycling.

In the present invention, the wax paste is heated to decompose the wax paste so as to remove and recover the complexed normal alkanes therein. The heating can be carried out in a conventional manner in the art, and the present application has no particular limitation thereto. The heating conditions include: the temperature can be 80-200°C, and the time can be 1-72h; preferably, the temperature can be 80-180°C, and the time can be 2-48h.

In the present invention, the conditions for the second filtration separation are not specifically limited, as long as the normal alkanes and the complexing agent can be fully separated.

In the present invention, the recycling can be to return the complexing agent obtained by the second filtration separation to step (A) for use as a dewaxing complexing agent alone, or to mix it with a fresh complexing agent and return them together to step (A) for use as a dewaxing complexing agent.

The third aspect of the present invention provides use of the complexing agent described in the first aspect in reducing the cloud point of Fischer-Tropsch synthetic oil.

The present invention will be described in detail below by way of examples. In the following examples and comparative examples,

The preparation process of the complexing agent used in the present invention is as follows:

(1) Component A is placed in a pulverizer for pulverization to obtain a powder of component A with a particle size of 100-200 mesh;

(2) placing component B in a pulverizer for pulverization to obtain a component B powder with a particle size of 80-100 mesh;

(3) The component A powder and the component B powder prepared above are fully mixed according to the mass ratio, and then kneaded in a kneader to obtain a complexing agent.

The complexing agents used in Examples 1-11 (respectively denoted as L1-L11) were prepared by the above process, and the composition parameters of the complexing agents are shown in Table 1.

Table 1

The Fischer-Tropsch synthetic oil used was purchased from the Coal-to-Liquids Branch of Ningxia Coal Industry Group Co., Ltd. of the State Energy Group.

Example 1

(A) adding the complexing agent L1 to the Fischer-Tropsch oil (cloud point of 42°C, initial boiling point of 200°C, final boiling point of 650°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch oil: complexing agent L1 is 10:1), reaction temperature of -5°C, reaction time of 48h, stirring rate of 300 rpm, to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation at -35°C to obtain dewaxed oil P1 and wax paste;

(C) heating the wax paste at 80° C. for 2 h, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Example 2

The method of Example 1 was followed, except that the complexing agent L2 was used. Other conditions were the same as those of Example 1. Dewaxed oil P2 was obtained.

Example 3

The method of Example 1 was followed, except that the complexing agent L3 was used. Other conditions were the same as those of Example 1. Dewaxed oil P3 was obtained.

Example 4

(A) adding the complexing agent L4 to the Fischer-Tropsch oil (cloud point of 23°C, initial boiling point of 200°C, final boiling point of 680°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch oil: complexing agent L4 is 20:1), reaction temperature of 50°C, reaction time of 10h, stirring rate of 600 rpm, to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation at 60° C. to obtain dewaxed oil P4 and wax paste;

(C) heating the wax paste at 100° C. for 35 hours, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Example 5

(A) adding the complexing agent L5 to the Fischer-Tropsch synthetic oil (cloud point of -30°C, initial boiling point of 180°C, final boiling point of 680°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch synthetic oil: complexing agent L5 is 1:1), reaction temperature of 80°C, reaction time of 1h, stirring rate of 100 rpm, to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation at -5°C to obtain dewaxed oil P5 and wax paste;

(C) heating the wax paste at 150° C. for 48 hours, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Example 6

(A) adding the complexing agent L6 to the Fischer-Tropsch oil (cloud point of 60°C, initial boiling point of 200°C, final boiling point of 660°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch oil: complexing agent L6 is 5:1), reaction temperature of 20°C, reaction time of 25h, stirring rate of 500 rpm, to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation at -15°C to obtain dewaxed oil P6 and wax paste;

(C) heating the wax paste at 180° C. for 10 h, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Example 7

(A) adding the complexing agent L7 to the Fischer-Tropsch oil (cloud point of -14°C, initial boiling point of 150°C, final boiling point of 650°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch oil: complexing agent L7 is 30:1), reaction temperature of 100°C, reaction time of 50h, stirring rate of 700 rpm, to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation at 100° C. to obtain dewaxed oil P7 and wax paste;

(C) heating the wax paste at 90° C. for 20 h, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Example 8

(A) adding the complexing agent L8 to the Fischer-Tropsch synthetic oil (cloud point of 60°C, initial boiling point of 160°C, final boiling point of 650°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch synthetic oil: complexing agent L8 is 50:1), reaction temperature of 40°C, reaction time of 0.5h, stirring rate of 30 rpm, and obtaining a reaction product;

(B) subjecting the reaction product to a first filtration separation at 60° C. to obtain dewaxed oil P8 and wax paste;

(C) heating the wax paste at 200° C. for 1 hour, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Example 9

(A) adding the complexing agent L9 to the Fischer-Tropsch oil (cloud point of 15°C, initial boiling point of 175°C, final boiling point of 650°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch oil: complexing agent L9 is 25:1), reaction temperature of 0°C, reaction time of 20h, stirring rate of 400 rpm, and obtaining a reaction product;

(B) subjecting the reaction product to a first filtration separation at 0° C. to obtain dewaxed oil P9 and wax paste;

(C) heating the wax paste at 160° C. for 55 hours, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Example 10

(A) adding the complexing agent L10 to the Fischer-Tropsch oil (cloud point of -30°C, initial boiling point of 160°C, final boiling point of 690°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch oil to complexing agent L10 is 40:1), reaction temperature of 70°C, reaction time of 72h, stirring rate of 800 rpm, to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation at -35°C to obtain dewaxed oil P10 and wax paste;

(C) heating the wax paste at 120° C. for 72 hours, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Embodiment 11

(A) adding the complexing agent L11 to the Fischer-Tropsch synthetic oil (cloud point of 35°C, initial boiling point of 155°C, final boiling point of 700°C), carrying out complexing reaction under stirring (mass ratio of Fischer-Tropsch synthetic oil: complexing agent L11 is 35:1), reaction temperature of 20°C, reaction time of 60h, stirring rate of 200 rpm, to obtain a reaction product;

(B) subjecting the reaction product to a first filtration separation at 10° C. to obtain dewaxed oil P11 and wax paste;

(C) heating the wax paste at 110° C. for 60 hours, and then performing a second filtration separation to obtain normal alkanes and a complexing agent. Recovering the normal alkanes, and returning the complexing agent to step (A) for recycling.

Comparative Example 1

The method of Example 1 was followed, except that the mass ratio of component A to component B in the complexing agent was 60:1. Other conditions were the same as those of Example 1. Dewaxed oil D1 was obtained.

Comparative Example 2

The method of Example 1 was followed, except that the mass ratio of Fischer-Tropsch synthetic oil to complexing agent L1 was 55:1. Other conditions were the same as those of Example 1. Dewaxed oil D2 was obtained.

Comparative Example 3

The method of Example 1 was followed, except that the reaction temperature in step (A) was 110° C. The other conditions were the same as those in Example 1. Dewaxed oil D3 was obtained.

Comparative Example 4

The method of Example 1 was followed, except that the reaction time in step (A) was 0.2 h. Other conditions were the same as those in Example 1. Dewaxed oil D4 was obtained.

Comparative Example 5

The method of Example 1 was followed, except that the complexing agent did not contain component B. Other conditions were the same as those of Example 1. Dewaxed oil D5 was obtained.

Comparative Example 6

The method of Example 1 was followed, except that the complexing agent did not contain component A. Other conditions were the same as those of Example 1. Dewaxed oil D6 was obtained.

Comparative Example 7

Add the prepared dewaxing liquid (urea: isopropanol: water mass ratio of 5:4:1) to Fischer-Tropsch synthetic oil (cloud point of 42°C, initial distillation point of 200°C, final distillation point of 650°C) at 50°C, where the mass ratio of Fischer-Tropsch synthetic oil to dewaxing liquid is 1:3. Stir at a stirring rate of 300 rpm and a temperature of 50°C for 48 hours, then filter and separate at -10°C to obtain dewaxing oil, alcohol aqueous solution and wax paste;

The dewaxed oil is heated to 90° C. to remove isopropanol, thereby obtaining dewaxed oil D7; isopropanol is recovered from the alcohol aqueous solution by distillation, thereby obtaining an 85 wt % isopropanol aqueous solution; water is added to the wax paste and heated to 80° C., thereby obtaining a urea aqueous solution and normal alkanes.

Test Case

The dewaxed oils (P1-P11, D1-D7) obtained in Examples 1-11 and Comparative Examples 1-7 were subjected to cloud point tests and isoparaffin content tests, and the cloud points of the dewaxed oils were compared with the cloud points of the Fischer-Tropsch synthetic oils before dewaxing treatment.

Turbidity point: measured using an automatic pour point turbidity meter (manufacturer: Haierchao, model: HCP-852);

Isoparaffin content: measured by gas chromatography (manufacturer: Agilent, model 7890B).

The test results are shown in Table 2.

Table 2

It can be seen from the results of Examples 1-11 and the comparative examples that the Fischer-Tropsch synthetic oil is treated by the complexing agent and method of the present invention, and the obtained product dewaxed oil has a significant decrease in cloud point of different magnitudes compared with the Fischer-Tropsch synthetic oil before treatment, and thus the low-temperature flow performance is significantly improved, which is specifically manifested as follows: for the raw material oil with a higher cloud point (such as the Fischer-Tropsch synthetic oil used in Examples 1-3, 6 and 8), the cloud point is greatly reduced after treatment; for the raw material oil with a lower cloud point (such as the Fischer-Tropsch synthetic oil used in Examples 4, 9 and 11), the cloud point is also significantly reduced after treatment; for the raw material oil with a lower cloud point (such as the Fischer-Tropsch synthetic oil used in Examples 5, 7 and 10), after treatment, although the decrease in the cloud point is somewhat different from the previous two, given that the cloud point of the raw material oil itself is already at a relatively low level, the effect of reducing the cloud point is also significant. In Examples 1-11, the isoparaffin content in the obtained dewaxed oil can reach more than 98wt%, and the normal alkane recovery rate is high. Comparative Examples 1-7 do not use the complexing agent or method of the present invention. Compared with Example 1, the cloud point reduction and low-temperature flow performance improvement effects of the dewaxed oil obtained after treatment are not ideal.

In particular, Comparative Examples 1, 5 and 6 did not use the complexing agent of the present invention, and the dewaxing effect was poor, resulting in the cloud point reduction and isoparaffin content of the product dewaxed oil being lower than those in Example 1; the complexing agent used in Comparative Example 5 did not contain component B, and the complexing agent used in Comparative Example 6 did not contain component A, and the cloud point reduction effects obtained by them were significantly lower than those in Example 1 (the complexing agent used contained both component A and component B); Comparative Example 7 used a conventional solvent dewaxing method, and the cloud point reduction and isoparaffin content of the product dewaxed oil were significantly lower than those in Example 1, which was significantly different from the technical effects of the present application.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims (34)

1. The complexing agent for reducing the cloud point of Fischer-Tropsch synthetic oil is characterized by comprising a component A and a component B, wherein the component A is at least one of cellulose, glucose, urea, thiourea, acetamide and propionamide, and the component B is at least one of diatomite, clay, kaolin, titanium pigment and pseudo-boehmite; wherein,

The component A comprises the following components: the mass ratio of the component B is (1-50): 1.

2. The complexing agent of claim 1 wherein component a is at least one of cellulose, urea, thiourea, propionamide;

the component B is at least one of clay, kaolin and titanium dioxide;

the component A comprises the following components: the mass ratio of the component B is (2-40): 1.

3. A method of reducing the cloud point of a fischer-tropsch synthetic oil, the method comprising:

(A) Carrying out complex reaction on Fischer-Tropsch synthesis oil and a complexing agent to obtain a reaction product;

(B) Performing first filtration and separation on the reaction product to obtain dewaxed oil and cerate;

Wherein in step (a), the complexing agent is the complexing agent of claim 1 or 2.

4. A process according to claim 3 wherein in step (a) the fischer-tropsch oil is the product of isomerisation of an oil product produced by a fischer-tropsch process.

5. The process of claim 4 wherein the fischer-tropsch synthesis oil has a cloud point of from-30 ℃ to 60 ℃.

6. The process of claim 5 wherein the fischer-tropsch synthesis oil has an initial boiling point of 150-200 ℃; the final distillation point of the Fischer-Tropsch synthesis oil is 650-700 ℃.

7. The process of claim 6 wherein the fischer-tropsch synthesis oil has an initial boiling point of 180-200 ℃; the final distillation point of the Fischer-Tropsch synthesis oil is 650-680 ℃.

8. A process according to any one of claims 3 to 7, wherein in step (a) the fischer-tropsch synthesis oil: the mass ratio of the complexing agent is (1-50): 1.

9. The process of claim 8, wherein in step (a), the fischer-tropsch synthesis oil: the mass ratio of the complexing agent is (1-20): 1.

10. The method according to any one of claims 3-7, 9, wherein in step (a), the conditions of the complexation reaction comprise: the temperature is between-5 ℃ and 100 ℃; the time is 0.5-72h.

11. The method of claim 10, wherein in step (a), the conditions of the complexation reaction comprise: the temperature is between-5 ℃ and 80 ℃; the time is 1-48h.

12. The method of claim 8, wherein in step (a), the conditions of the complexation reaction comprise: the temperature is between-5 ℃ and 100 ℃; the time is 0.5-72h.

13. The method of claim 12, wherein in step (a), the conditions of the complexation reaction comprise: the temperature is between-5 ℃ and 80 ℃; the time is 1-48h.

14. The method of claim 10, wherein the conditions of the complexation reaction further comprise stirring, the stirring being at a rate of 30-800 revolutions per minute.

15. The method of claim 14, wherein the conditions of the complexation reaction further comprise stirring, the stirring being at a rate of 100-600 rpm.

16. The method of any one of claims 11-13, wherein the conditions of the complexation reaction further comprise stirring, the stirring being at a rate of 30-800 revolutions per minute.

17. The method of claim 16, wherein the conditions of the complexation reaction further comprise stirring, the stirring being at a rate of 100-600 rpm.

18. The method of any one of claims 3-7, 9, 11-15, 17, wherein in step (B), the conditions of the first filtering separation include: the temperature is-35 ℃ to 100 ℃.

19. The method of claim 8, wherein in step (B), the conditions of the first filtering separation include: the temperature is-35 ℃ to 100 ℃.

20. The method of claim 10, wherein in step (B), the conditions of the first filtering separation include: the temperature is-35 ℃ to 100 ℃.

21. The method of claim 16, wherein in step (B), the conditions of the first filtering separation include: the temperature is-35 ℃ to 100 ℃.

22. The method of claim 18, wherein in step (B), the conditions of the first filtering separation include: the temperature is-35 ℃ to 60 ℃.

23. The method of any one of claims 19-21, wherein in step (B), the first filter-separation condition comprises: the temperature is-35 ℃ to 60 ℃.

24. The method of any one of claims 3-7, 9, 11-15, 17, 19-22, wherein the method further comprises: heating the cerate and performing second filtering separation to obtain normal alkane and the complexing agent;

wherein the complexing agent is returned to the step (A) for recycling.

25. The method of claim 8, wherein the method further comprises: heating the cerate and performing second filtering separation to obtain normal alkane and the complexing agent;

wherein the complexing agent is returned to the step (A) for recycling.

26. The method of claim 10, wherein the method further comprises: heating the cerate and performing second filtering separation to obtain normal alkane and the complexing agent;

wherein the complexing agent is returned to the step (A) for recycling.

27. The method of claim 16, wherein the method further comprises: heating the cerate and performing second filtering separation to obtain normal alkane and the complexing agent;

wherein the complexing agent is returned to the step (A) for recycling.

28. The method of claim 18, wherein the method further comprises: heating the cerate and performing second filtering separation to obtain normal alkane and the complexing agent;

wherein the complexing agent is returned to the step (A) for recycling.

29. The method of claim 23, wherein the method further comprises: heating the cerate and performing second filtering separation to obtain normal alkane and the complexing agent;

wherein the complexing agent is returned to the step (A) for recycling.

30. The method of claim 24, wherein the heating conditions comprise: the temperature is 80-200 ℃; the time is 1-72h.

31. The method of any of claims 25-29, wherein the heating conditions comprise: the temperature is 80-200 ℃; the time is 1-72h.

32. The method of claim 30, wherein the heating conditions comprise: the temperature is 80-180 ℃; the time is 2-48h.

33. The method of claim 31, wherein the heating conditions comprise: the temperature is 80-180 ℃; the time is 2-48h.

34. Use of a complexing agent as claimed in claim 1 or claim 2 for reducing the cloud point of a fischer-tropsch synthetic oil.