Method for removing oxygen-containing compounds from high carbon number Fischer-Tropsch oils

Abstract

This disclosure discloses a method for removing oxygen-containing compounds from Fischer-Tropsch oil with a high carbon number, which relates to the chemical engineering field. The method for removing oxygen-containing compounds from Fischer-Tropsch oil with a high carbon number adopts a combined reaction-extraction process, firstly, Fischer-Tropsch oil (C5-C20) is washed with alkali using an aqueous alkali solution to convert acidic substances into salts that are easily dissolved in water, and esters are hydrolyzed and removed by washing with water, and the first extraction is performed with a carbonate extractant to remove alcohols and esters in the Fischer-Tropsch oil, and the second extraction is performed with propylene carbonate to remove ketones and aldehydes impurities in the Fischer-Tropsch oil, thereby achieving the purpose of effectively removing oxygen-containing compounds from the Fischer-Tropsch oil, and after extraction, the content of oxygen-containing compounds in the Fischer-Tropsch oil can be reduced to 1-60 ppm, and the yield of petroleum products can be maintained at 90% or more.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202111667068.1, entitled "Method for Removing Oxygen-Containing Compounds in High Carbon Number Fischer-Tropsch Oil," filed on December 31, 2021, the contents of which are incorporated herein by reference in their entirety.

[0002] <Technical field> The present disclosure relates to the chemical engineering field, and in particular to a method for removing oxygen-containing compounds in high carbon number Fischer-Tropsch oils. [Background technology]

[0003] Fischer-Tropsch oil contains a large amount of α-alkenes and has many downstream applications, but during the Fischer-Tropsch reaction process, it produces about 5 wt% of oxygen-containing compounds, which are mainly classified into five types: aldehydes, acids, alcohols, ketones, and esters. If such impurities are contained in the product, it will affect the application of downstream products, so it is necessary to take measures to remove the oxygen-containing compounds.

[0004] In CN106753546A (2017), a strong alkaline aqueous dimethyl sulfoxide solution composite extractant is used to remove oxygen-containing compounds, and the extracted Fischer-Tropsch synthetic light oil is further passed through a silica gel dryer, after which the total content of oxygen-containing compounds is less than 0.05%. In CN112745909A (2019), an ethylene glycol composite extractant is used, where the composite extractant contains a main solvent and a co-solvent, the main solvent is an ethylene glycol compound, and the co-solvent is water, ammonia water, alcohol amine compound, amide compound or sulfone compound, and the yield of hydrocarbon compounds can reach more than 96% by mass.

[0005] However, most of the conventional processes are aimed at petroleum products with low carbon numbers, and the higher the carbon number of the petroleum product, the more difficult it is to remove oxygen-containing compounds. Conventionally, it has been difficult to effectively remove oxygen-containing compounds from petroleum products with high carbon numbers. In view of this, we particularly propose this publication. Summary of the Invention [Problem to be solved by the invention]

[0006] The objective of the present disclosure is at least to provide a method for removing oxygen-containing compounds in a high carbon number Fischer-Tropsch oil, which ensures the yield of petroleum products and effectively removes oxygen-containing compounds in high carbon number petroleum products. [Means for solving the problem]

[0007] This release will be made as follows:

[0008] In a first aspect, the disclosure provides a method for removing oxygen-containing compounds in a Fischer-Tropsch oil having a high carbon number, the method comprising sequentially subjecting the Fischer-Tropsch oil to an alkali wash, a water wash and an extraction, in which the extraction includes a first extraction and a second extraction, the first extraction being performed using a carbonate extractant, and the second extraction being performed using propylene carbonate, and the carbon number of the Fischer-Tropsch oil is C5-C20.

[0009] In a preferred embodiment, the volume ratio of the Fischer-Tropsch oil to the carbonate extractant is controlled to 1:1-10, preferably 1:2-6, in the course of the first extraction.

[0010] Preferably, the Fischer-Tropsch oil has a carbon number of C10-C20.

[0011] In an alternative embodiment, the carbonate extractant is at least one selected from the group consisting of ethylene carbonate, butylene carbonate, diethyl carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, and trimethylene carbonate.

[0012] In an alternative embodiment, the volume ratio of Fischer-Tropsch oil to propylene carbonate in the second extraction process is controlled to be 1:1-10, preferably 1:2-6.

[0013] In an alternative embodiment, the first extraction and the second extraction are both carried out in a sieve plate extraction tower, and the extraction temperature is 20-25°C.

[0014] Preferably, the vibration frequency of the sieve plate extraction tower is 1 to 500 times / min, the aperture ratio of the sieve plates is 1 to 99%, and the ratio of the spacing between the sieve plates to the height of the sieve plate tower is 1 to 50:100.

[0015] In an alternative embodiment, the alkaline cleaning is carried out using an alkaline aqueous solution, the alkaline aqueous solution including at least one of NaOH, KOH, NaHCO3, Na2CO3, K2CO3, Ca(OH)2, and KHCO3.

[0016] In an alternative embodiment, the mass concentration of the alkaline aqueous solution is 10-30%, the volume ratio of the Fischer-Tropsch oil to the alkaline aqueous solution is 1:1-3, and preferably the operation time of the alkaline washing is 1-3 h.

[0017] In an alternative embodiment, the alkaline washing is carried out under stirring conditions or in a static mixer, and after the alkaline washing, the mixture is allowed to stand and separated. Preferably, when the alkaline washing is carried out using a static mixer, the ratio of the reflux amount and the extraction amount of the static mixer is controlled to be 2-8:1.

[0018] In an alternative embodiment, in the water-washing process, the volume ratio of the Fischer-Tropsch oil to water is controlled to 1:2-4, and the water-washing time is controlled to 1-2 hours.

[0019] In an alternative embodiment, the water washing is carried out under stirring conditions or in a static mixer, and after the water washing, the mixture is allowed to stand and separated into layers. Preferably, when the water washing is carried out using a static mixer, the ratio of the reflux amount and the extraction amount of the static mixer is controlled to be 2 to 8:1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The disclosed embodiment can have the following beneficial effects: A reaction-extraction combination process is adopted, and an alkaline aqueous solution is first used to carry out alkaline washing on Fischer-Tropsch oil (C5-C20), converting acidic substances into salts that are easily dissolved in water, hydrolyzing esters and removing them by washing with water, and a first extraction is carried out with a carbonate extractant to remove alcohols and esters in the Fischer-Tropsch oil, and a second extraction is carried out with propylene carbonate to remove ketones and aldehydes impurities in the Fischer-Tropsch oil, thereby achieving the purpose of effectively removing oxygen-containing compounds in the Fischer-Tropsch oil, and after extraction, the content of oxygen-containing compounds in the Fischer-Tropsch oil is reduced to 1-60 ppm, and the yield of oil products is maintained at 90% or more.

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of this disclosure clearer, the technical solutions in the embodiments of this disclosure are clearly and completely described below. In the embodiments, unless specific conditions are specified, they are carried out according to general conditions or conditions suggested by the manufacturer. For reagents or equipment used without specifying the manufacturer, they are all general products available on the market.

[0022] The present disclosure provides a method for removing oxygen-containing compounds in Fischer-Tropsch oil with a high carbon number, which adopts a combined reaction-extraction process, has a very good treatment effect on Fischer-Tropsch oil with a carbon number of C5-C20 (preferably C10-C20), can effectively remove oxygen-containing compounds in Fischer-Tropsch oil, and can guarantee the yield of Fischer-Tropsch oil. Specifically, the method includes the following steps:

[0023] S1. Alkaline cleaning The Fischer-Tropsch oil is subjected to an alkaline wash, in which acidic substances are converted into salts which are easily dissolved in water, and esters are hydrolyzed and removed by washing with water in the subsequent process.

[0024] Specifically, the alkaline washing is carried out using an alkaline aqueous solution at room temperature (20 to 25°C). The alkaline aqueous solution contains at least one of NaOH, KOH, NaHCO3, Na2CO3, K2CO3, Ca(OH)2 and KHCO3. The alkaline aqueous solution may contain one or more basic raw materials, but is not limited thereto.

[0025] In some embodiments, the mass concentration of the alkaline aqueous solution is 10-30%, specifically 10%, 15%, 20%, 25%, 30%, etc., or any value between the adjacent mass concentrations. The volume ratio of the Fischer-Tropsch oil to the alkaline aqueous solution is 1:1-3, specifically 1:1, 1:2, 1:3, etc., or any value between the adjacent ratio values. The operation time of the alkaline washing is 1-3h, specifically 1h, 1.5h, 2h, 2.5h, 3h, etc., or any value between the adjacent time values.

[0026] In some embodiments, in order to sufficiently carry out the reaction, the alkaline washing is carried out under stirring conditions or in a static mixer, and after the alkaline washing, the mixture is allowed to stand for layer separation, and the standing time may be 20 to 60 minutes.

[0027] Specifically, the static mixer may be a general static mixer, which can be used instead of stirring. During the operation, the outlet of the static mixer is returned to the inlet. The ratio of the return amount of the static mixer to the extraction amount is usually controlled to be 2-8:1, and may be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, etc., or any value between the adjacent ratio values.

[0028] S2. Washing with water The water washing may be performed using deionized water at room temperature (20 to 25°C). In order to sufficiently remove salts and the like produced in the alkaline washing, the volume ratio of the Fischer-Tropsch oil to the deionized water is controlled to 1:2 to 4, and the water washing time is controlled to 1 to 2 hours.

[0029] Specifically, the volume ratio of the Fischer-Tropsch oil to the deionized water may be 1:2, 1:3, 1:4, etc., or any value between the adjacent volume ratios. The water washing time may be 1 h, 1.5 h, 2 h, etc., or any value between the adjacent time values.

[0030] Similarly, washing with water may also be carried out under stirring conditions or in a static mixer, and after washing with water, the mixture may be allowed to stand to separate into layers, and the standing time may be from 20 to 60 minutes.

[0031] Similarly, the static mixer may be a general static mixer, which can be substituted for stirring. During the operation, the outlet of the static mixer is returned to the inlet. The ratio of the return amount of the static mixer to the extraction amount is usually controlled to 2-8:1, and may be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, etc., or any value between the adjacent ratio values ​​above.

[0032] S3. First extraction The first extraction is carried out using a carbonate extractant, and the alcohol and esters in the Fischer-Tropsch oil can be removed by the first extraction.

[0033] In some embodiments, in the first extraction process, the volume ratio of the Fischer-Tropsch oil to the carbonate extractant is controlled to 1:1 to 10, preferably 1:2 to 6. The volume ratio of the Fischer-Tropsch oil to the carbonate extractant may be controlled to 1:1, 1:2, 1:3, 1:4, 1:5, etc., or any value between the adjacent ratio values.

[0034] In some embodiments, the carbonate extractant is at least one selected from the group consisting of ethylene carbonate, butylene carbonate, diethyl carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate and trimethylene carbonate. All of the above carbonate extractants can effectively remove alcohol and ester in the Fischer-Tropsch oil, and a single extractant or a mixture of extractants may be used, but is not limited thereto.

[0035] In some embodiments, the first extraction process is carried out in a sieve plate extraction tower, and the extraction temperature is 20-25° C., i.e., at room temperature. The vibration frequency of the sieve plate extraction tower is 1-500 times / min, the aperture ratio of the sieve plate is 1-99%, and the ratio of the spacing between the sieve plates to the height of the sieve plate tower is 1-50:100.

[0036] Specifically, the vibration frequency of the sieve plate extraction tower may be 1 vibration / min, 20 vibrations / min, 60 vibrations / min, 80 vibrations / min, 100 vibrations / min, 120 vibrations / min, 140 vibrations / min, 160 vibrations / min, 180 vibrations / min, 200 vibrations / min, 220 vibrations / min, 240 vibrations / min, 260 vibrations / min, 280 vibrations / min, 300 vibrations / min, 320 vibrations / min, 340 vibrations / min, 360 vibrations / min, 380 vibrations / min, 400 vibrations / min, 420 vibrations / min, 440 vibrations / min, 460 vibrations / min, 480 vibrations / min, 500 vibrations / min, etc., or may be any value between the adjacent vibration frequencies listed above. The aperture ratio of the sieve plates may be 1%, 10%, 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 80%, 90%, 99%, etc., or any value between the adjacent aperture ratios listed above. The ratio of the spacing between the sieve plates to the height of the sieve plate tower may be 1:100, 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, 45:100, 50:100, etc., or any value between the adjacent ratios listed above.

[0037] S4. Second extraction The second extraction is carried out using propylene carbonate, which can effectively remove ketones and aldehydes impurities in the Fischer-Tropsch oil.

[0038] In some embodiments, in the process of the second extraction, the volume ratio of the Fischer-Tropsch oil to the propylene carbonate is controlled to 1:1 to 10, preferably 1:2 to 6. Specifically, it may be 1:1, 1:2, 1:3, 1:4, 1:5, etc., or any value between the adjacent volume ratios.

[0039] In some embodiments, the first and second extraction processes are both carried out in a sieve plate extraction tower, and the extraction temperature is 20-25° C., i.e., at room temperature. The vibration frequency of the sieve plate extraction tower is 1-500 times / min, the aperture ratio of the sieve plate is 1-99%, and the ratio of the spacing between the sieve plates to the height of the sieve plate tower is 1-50:100.

[0040] Specifically, the vibration frequency of the sieve plate extraction tower may be 1 vibration / min, 20 vibrations / min, 60 vibrations / min, 80 vibrations / min, 100 vibrations / min, 120 vibrations / min, 140 vibrations / min, 160 vibrations / min, 180 vibrations / min, 200 vibrations / min, 220 vibrations / min, 240 vibrations / min, 260 vibrations / min, 280 vibrations / min, 300 vibrations / min, 320 vibrations / min, 340 vibrations / min, 360 vibrations / min, 380 vibrations / min, 400 vibrations / min, 420 vibrations / min, 440 vibrations / min, 460 vibrations / min, 480 vibrations / min, 500 vibrations / min, etc., or may be any value between the adjacent vibration frequencies listed above. The aperture ratio of the sieve plates may be 1%, 10%, 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 80%, 90%, 99%, etc., or any value between the adjacent aperture ratios listed above. The ratio of the spacing between the sieve plates to the height of the sieve plate tower may be 1:100, 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, 45:100, 50:100, etc., or any value between the adjacent ratios listed above.

[0041] After the second extraction is completed, the extractant can be recovered by a common method such as rectification, but the description of this will be omitted here.

[0042] The features and performance of the present disclosure will be described in more detail below with reference to examples.

[0043] Example 1 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0044] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, among which the content of alcohol is 3.2%, the content of aldehyde is 0.4%, the content of acid is 0.5%, the content of ester is 0.4%, and the content of ketone is 0.5%.

[0045] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 10 L of 10 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, and the mixture was stirred for 1 hour and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0046] First extraction: 10L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the rotation speed of the centrifugal extractor is 2000r / min, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0047] Second extraction: 20L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0048] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 36 ppm, and the yield of petroleum products was 95%.

[0049] Example 2 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0050] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, among which the content of alcohol is 3.4%, the content of aldehyde is 0.5%, the content of acid is 0.5%, the content of ester is 0.3%, and the content of ketone is 0.3%.

[0051] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 10 L of 5 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, stirred for 1 hour, and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0052] First extraction: 10L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 120 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0053] Second extraction: 20L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 120 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0054] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 30 ppm, and the yield of petroleum products was 94%.

[0055] Example 3 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0056] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, the content of alcohol is 3.2%, the content of aldehyde is 0.6%, the content of acid is 0.6%, the content of ester is 0.3%, and the content of ketone is 0.3%.

[0057] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 10 L of 20 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, stirred for 1 hour, and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0058] First extraction: 20L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0059] Second extraction: 25L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0060] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 35 ppm, and the yield of petroleum products was 92%.

[0061] Example 4 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0062] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, among which the content of alcohol is 3.5%, the content of aldehyde is 0.5%, the content of acid is 0.5%, the content of ester is 0.3%, and the content of ketone is 0.2%.

[0063] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 10 L of 20 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, stirred for 1 hour, and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0064] First extraction: 10L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 120 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0065] Second extraction: 20L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 120 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0066] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 28 ppm, and the yield of petroleum products was 92.6%.

[0067] Example 5 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0068] Fischer-Tropsch oil feedstock: the content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, the content of alcohol is 3.8%, the content of aldehyde is 0.5%, the content of acid is 0.3%, the content of ester is 0.2%, and the content of ketone is 0.2%.

[0069] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 20 L of 5 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, stirred for 1 hour, and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0070] First extraction: 10L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 120 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0071] Second extraction: 20L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 120 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0072] The detection revealed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 38 ppm, and the yield of petroleum products was 91%.

[0073] Example 6 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0074] Fischer-Tropsch oil feedstock: the content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, the content of alcohol is 3.6%, the content of aldehyde is 0.4%, the content of acid is 0.4%, the content of ester is 0.3%, and the content of ketone is 0.3%.

[0075] Alkali washing and water washing: 10L of Fischer-Tropsch oil was taken, 10L of 5wt% NaOH aqueous solution was added to the Fischer-Tropsch oil, mixed in a static mixer, and the reflux / extraction ratio was 3:1. The mixture was allowed to stand for 30min to separate into layers. Then, the aqueous phase was removed, and 10L of deionized water was added to perform water washing.

[0076] First extraction: 20L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0077] Second extraction: 25L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0078] The detection revealed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 34 ppm, and the yield of petroleum products was 93%.

[0079] Example 7 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0080] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, among which the content of alcohol is 3.6%, the content of aldehyde is 0.5%, the content of acid is 0.5%, the content of ester is 0.2%, and the content of ketone is 0.2%.

[0081] Alkali washing and water washing: 10L of Fischer-Tropsch oil was taken, 10L of 5wt% NaOH aqueous solution was added to the Fischer-Tropsch oil, mixed in a static mixer, and the reflux / extraction ratio was 7:1. The mixture was allowed to stand for 30min to separate into layers. Then, the aqueous phase was removed, and 20L of deionized water was added to perform water washing.

[0082] First extraction: 20L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0083] Second extraction: 25L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0084] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 30 ppm, and the yield of petroleum products was 93.5%.

[0085] Example 8 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0086] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, among which the content of alcohol is 3.5%, the content of aldehyde is 0.6%, the content of acid is 0.5%, the content of ester is 0.2%, and the content of ketone is 0.1%.

[0087] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 10 L of 5 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, stirred for 1 hour, and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0088] First extraction: 10L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0089] Second extraction: 20L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 50%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0090] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 33 ppm, and the yield of petroleum products was 90.5%.

[0091] Example 9 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0092] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, among which the content of alcohol is 3.3%, the content of aldehyde is 0.6%, the content of acid is 0.5%, the content of ester is 0.4%, and the content of ketone is 0.2%.

[0093] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 10 L of 20 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, stirred for 1 hour, and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0094] First extraction: 20L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 60%, and the spacing of the sieve plates of the sieve plate extraction tower is 10% of the height of the sieve plate tower.

[0095] Second extraction: 25L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 80 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 60%, and the spacing of the sieve plates of the sieve plate extraction tower is 10% of the height of the sieve plate tower.

[0096] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 32 ppm, and the yield of petroleum products was 92.5%.

[0097] Example 10 This example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0098] Fischer-Tropsch oil feedstock: The content of oxygen-containing compounds in Fischer-Tropsch oil (C8) is 5%, including alcohol, aldehyde, acid, ester and ketone, the content of alcohol is 3.7%, the content of aldehyde is 0.6%, the content of acid is 0.4%, the content of ester is 0.2%, and the content of ketone is 0.1%.

[0099] Alkali washing and water washing: 10 L of Fischer-Tropsch oil was taken, 10 L of 20 wt % NaOH aqueous solution was added to the Fischer-Tropsch oil, stirred for 1 hour, and allowed to stand for 30 minutes to separate into layers. After that, the aqueous phase was removed, and 10 L of deionized water was added to perform water washing.

[0100] First extraction: 10L of butylene carbonate extractant is added to the Fischer-Tropsch oil after water washing, the vibration frequency of the sieve plate extraction tower is 100 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0101] Second extraction: 30L of propylene carbonate is added to 10L of Fischer-Tropsch oil after butylene carbonate extraction, the vibration frequency of the sieve plate extraction tower is 100 times / min, the opening rate of the sieve plate of the sieve plate extraction tower is 55%, and the spacing of the sieve plates of the sieve plate extraction tower is 5% of the height of the sieve plate tower.

[0102] The detection results showed that the content of oxygen-containing compounds in the Fischer-Tropsch oil was 40 ppm, and the yield of petroleum products was 93.6%.

[0103] Comparative Example 1 This comparative example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0104] The composition is the same as that of the Fischer-Tropsch oil product in Example 1.

[0105] The removal method differed from Example 1 only in that ethylene glycol was used instead of butylene carbonate during the first extraction.

[0106] The detection revealed that the alcohol removal rate was 35% lower than in Example 1, and the residual rate of the extractant was 0.035%.

[0107] Comparative Example 2 This comparative example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0108] The composition is the same as that of the Fischer-Tropsch oil product in Example 3.

[0109] The removal method differed from Example 3 only in that glycerol was used instead of butylene carbonate in the first extraction.

[0110] It was found that the alcohol removal rate was 40% lower than that in Example 3, and the residual rate of the extractant in the Fischer-Tropsch oil was 0.033%.

[0111] Comparative Example 3 This comparative example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0112] The composition is the same as that of the Fischer-Tropsch oil product in Example 6.

[0113] The removal method differs from Example 6 only in that sulfolane was used instead of propylene carbonate in the second extraction.

[0114] The detection showed that the removal rates of aldehydes and ketones were reduced by 32% and 36%, respectively, and the residual rate of the extractant in the Fischer-Tropsch oil was 0.014%.

[0115] Comparative Example 4 This comparative example provides a method for removing oxygen-containing compounds from Fischer-Tropsch oil, and is specifically as follows.

[0116] The composition is the same as that of the Fischer-Tropsch oil product in Example 10.

[0117] The removal method differed from that of Example 10 only in that N-methylpyrrolidone was used instead of propylene carbonate in the second extraction.

[0118] The detection showed that the removal rates of aldehydes and ketones were reduced by 38% and 35%, respectively, and the residual rate of the extractant in the Fischer-Tropsch oil was 0.028%.

[0119] In conclusion, the disclosed embodiment provides a method for removing oxygen-containing compounds in Fischer-Tropsch oil with a high carbon number, adopting a combined reaction-extraction process, which has the following advantages over conventional processes: (1) It is suitable for removing oxygen-containing compounds in petroleum products with a high carbon number, and has a high removal rate. (2) The reagents used in the process are non-toxic and easy to regenerate, which meets the requirements for environmental protection. (3) The sieve plate extraction tower used is more suitable for the process provided by the disclosed embodiment, which can effectively remove oxygen-containing compounds while ensuring the yield of petroleum products.

[0120] The above is only a preferred embodiment of the present disclosure, and is not intended to limit the present disclosure, and those skilled in the art may have various modifications and changes to the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the scope of the spirit and principles of the present disclosure should be included in the scope of the claims of the present disclosure.

Claims

1. The Fischer-Tropsch oil is sequentially subjected to alkali washing, water washing and extraction, the extraction including a first extraction and a second extraction, the first extraction being performed using a carbonate extractant, and the second extraction being performed using propylene carbonate; The carbonate extractant is at least one selected from the group consisting of butylene carbonate, diethyl carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, and trimethylene carbonate, A method for removing oxygen-containing compounds from a high carbon number Fischer-Tropsch oil, characterized in that the Fischer-Tropsch oil has a carbon number of C5-C20.

2. 2. The method according to claim 1, wherein the volume ratio of the Fischer-Tropsch oil to the carbonate extractant is 1:1 to 10 in the first extraction step.

3. 2. The method according to claim 1, wherein the carbonate extractant is butylene carbonate.

4. The method according to claim 1, wherein the volume ratio of Fischer-Tropsch oil to propylene carbonate is controlled to 1:1-10 in the second extraction process.

5. The removal method according to any one of claims 1 to 4, characterized in that the first extraction and the second extraction are both carried out in a sieve plate extraction tower, and the extraction temperature is 20 to 25°C.

6. The alkaline cleaning is carried out using an alkaline aqueous solution, which may contain NaOH, KOH, NaHCO ３ , Na ２ CO ３ , K ２ CO ３ , Ca(OH) ２ and KHCO ３ 2. The method according to claim 1, further comprising the step of:

7. The method according to claim 6, characterized in that the mass concentration of the alkaline aqueous solution is 10 to 30%, and the volume ratio of the Fischer-Tropsch oil to the alkaline aqueous solution is 1:1 to 1:

3.

8. The alkaline washing is carried out under stirring conditions or in a static mixer, and after the alkaline washing, the mixture is allowed to stand and separated into layers; The method according to claim 7, wherein when the static mixer is used for alkaline cleaning, the ratio of the return flow rate of the static mixer to the extraction flow rate is controlled to be 2 to 8:

1.

9. 2. The method according to claim 1, wherein the volume ratio of the Fischer-Tropsch oil to water is controlled to 1:2-4 in the water washing step.

10. The washing with water is carried out under stirring conditions or in a static mixer, and after washing with water, the mixture is allowed to stand to separate into layers; The method according to claim 9, wherein when the static mixer is used for washing, the ratio of the return flow rate of the static mixer to the extraction flow rate is controlled to be 2 to 8:1.