A method for removing phospholipids from crude oil by anhydration

Abstract

The invention discloses a method for removing phospholipids from crude oil by anhydration. The method comprises the following steps: filtering out coarse oil residues in raw material crude oil to obtain crude oil without coarse residues; filtering out fine oil residues in the crude oil without coarse residues to obtain clear oil; cooling the clear oil to obtain cooled clear oil; filtering the cooled clear oil to obtain phospholipid-free oil. The method does not need to add chemical reagents or water, thus avoiding the loss of flavor substances in oil during dehydration and distillation in traditional processes and the damage to the oil structure after adding chemicals, and can reduce the phospholipid content in edible oil to within a qualified range, while ensuring the quality of edible oil and retaining the original flavor of the oil. The method also saves production water, avoids environmental pollution, saves environmental protection, and reduces costs.

Description

Technical Field

[0001] The invention relates to the technical field of edible oil processing, in particular to a method for removing phospholipids from crude oil by anhydration. Background Art

[0002] As people's living standards improve, the requirements for edible oils such as peanut oil are getting higher and higher.

[0003] The phospholipid content of crude peanut oil, for example, produced by the traditional cold-pressing process is 3.4-4.2 mg / g. The presence of a certain amount of phospholipids will affect the quality of edible oils such as peanut oil. It is necessary to remove the phospholipids in the later refining process to reduce the phospholipid content to an acceptable range.

[0004] The existing phospholipid removal process usually requires the addition of chemical reagents and water, which results in the destruction of the oil structure after the addition of chemicals; and requires dehydration and distillation treatment, which results in the loss of flavor substances in the oil; and requires a large number of raw materials such as chemical reagents and water, which is easy to cause pollution and increase costs. Summary of the invention

[0005] The invention aims to provide a method for removing phospholipids from crude oil by anhydration, so as to reduce the phospholipid content in edible oil to within an acceptable range, ensure the quality of edible oil, and avoid adding chemical reagents and water to avoid destroying the structure of edible oil, retain the original flavor of edible oil, save environment and reduce cost.

[0006] In a first aspect, the present invention provides a method for removing phospholipids from crude oil by anhydration, comprising the following steps:

[0007] Step S1, filtering out the crude oil residue in the raw material crude oil to obtain crude oil without coarse residue,

[0008] Step S2, filtering out the fine oil residue in the crude oil to obtain clear oil,

[0009] Step S3, cooling the clear oil to obtain cooled clear oil,

[0010] Step S4, filtering the cooled clear oil to obtain phospholipid-free oil.

[0011] Step S2 may be repeated to form a filter cake through which the filtered fine oil residue passes when filtering out the fine oil residue.

[0012] In step S2, the fine oil residue in part of the crude oil after de-coarsening is filtered out, and then mixed with the rest of the crude oil after de-coarsening, and step S2 is repeated to obtain clear oil; the fine oil residue has a mesh size of 30-80.

[0013] In a second aspect, the present invention provides a device for removing phospholipids from crude oil by anhydration, which is used to implement the method for removing phospholipids from crude oil by anhydration as described in the first aspect of the present invention. The device for removing phospholipids from crude oil by anhydration comprises an oil clarifier, a residue filter, a cooler and a filter. The oil clarifier is used to add the raw crude oil and to filter out the coarse oil residue in the raw crude oil to obtain the crude oil without coarse residue. The residue filter is used to filter out the fine oil residue in the crude oil without coarse residue to obtain the clear oil. The cooler is used to cool the clear oil to obtain the cooled clear oil. The filter is used to filter the cooled clear oil to obtain the phospholipid-free oil.

[0014] The oil clarifier is provided with a scraper for scooping out the coarse oil residue and stirring the fine oil residue to be suspended in the crude oil.

[0015] The residue filter may be provided with an oil pump for extracting the crude oil in the oil clarifier tank and sending it to the residue filter.

[0016] The residue filter machine may include a coarse residue filter machine and a fine residue filter machine. The coarse residue filter machine is used to filter out the fine oil residue in the crude oil without coarse residue to obtain the crude oil without fine residue; the fine residue filter machine is used to filter out the fine oil residue in the crude oil without fine residue to obtain the clean oil.

[0017] It can be seen that compared with the prior art, the present invention has at least the following beneficial effects:

[0018] The method for removing phospholipids from crude oil by anhydration does not need to add chemical reagents or water, thus avoiding the loss of flavor substances in oils and fats during dehydration and distillation in traditional processes and the damage to the oil and fat structure after adding chemicals, and can reduce the phospholipid content in edible oils and fats to within a qualified range, while ensuring the quality of the edible oil and fats and retaining the original flavor of the oil and fats; and can save production water, avoid environmental pollution, save environmental protection, reduce costs, and improve the quality and efficiency of phospholipid removal.

[0019] The device for removing phospholipids from crude oil by anhydration is suitable for realizing the method for removing phospholipids from crude oil by anhydration. It has reasonable structure, convenient use, low cost and improves production quality and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a method for removing phospholipids from crude oil by anhydration according to an embodiment of the present invention.

[0021] Figure 2 The present invention is a structural diagram of a device for removing phospholipids from crude oil by anhydration according to an embodiment of the present invention.

[0022] In the figure: 100 is crude oil with fine residue removed, 200 is clean oil, 1 is oil clarifier, 2 is residue filter, 201 is scraper, 202 is oil pump, 203 is coarse residue filter, 204 is fine residue filter, 3 is cooler, 4 is filter, and 5 is oil residue conveyor. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] like Figure 1 As shown, a method for removing phospholipids from crude oil by anhydration comprises the following steps:

[0026] Step S1, filtering out the crude oil residue in the raw material crude oil to obtain crude oil without coarse residue,

[0027] Step S2, filtering out the fine oil residue in the crude oil to obtain clear oil 200,

[0028] Step S3, cooling the clear oil 200 to obtain cooled clear oil.

[0029] Step S4, filtering the cooled clear oil to obtain phospholipid-free oil.

[0030] The method for removing phospholipids from crude oil by anhydration of this embodiment is particularly suitable for edible oils such as peanut crude oil obtained by cold pressing. The peanut oil obtained by cold pressing generally has a phospholipid content of 3.4-4.2 mg / g. The presence of phospholipids at this content affects the quality of the oil. Therefore, the method for removing phospholipids from crude oil by anhydration of this embodiment can be combined with the device for removing phospholipids from crude oil by anhydration of this embodiment to remove excess phospholipids in the crude peanut oil during the later refining process, so that the phospholipid content is reduced to a qualified range.

[0031] Therefore, preferably, in step S1, the phospholipid content of the raw crude oil is preferably 3.4-4.2 mg / g, that is, not higher than 4.2 mg / g.

[0032] Preferably, in step S1, the raw material is first roasted to make the phospholipid content of the raw material crude oil lower than 4.2 mg / g, or 3.4-4.2 mg / g, and then the coarse oil residue in the raw material crude oil is filtered out.

[0033] Preferably, the baking temperature may be 68-75° C. and the baking time may be 50 min.

[0034] Taking peanut raw materials as an example, the baking temperature is 68-75℃, and the baking time is 50min. At this time, the crude oil phospholipid content of the roasted peanut raw materials produced by the subsequent low-temperature pressing process is 3.4-4.2mg / g; if the baking temperature is increased to 75-86℃, and the baking time is 50 minutes, at this time, the NSI value of peanut protein produced by the subsequent low-temperature pressing process of the roasted peanut raw materials is above 68%, which meets the activity requirements of protein powder, but the crude oil phospholipid content is 4.3-5.6mg / g. The phospholipid content is high, and it is difficult to reduce it to the qualified requirements even after the subsequent phospholipid removal process.

[0035] Preferably, in step S1, the raw crude oil can be stirred. The crude oil residue can be one or both of granular and irregular flake. The mesh size of the crude oil residue can be 4-30 meshes. The weight percentage of the filtered crude oil residue to the raw crude oil can be 10%.

[0036] Preferably, in step S1, when the temperature of the crude oil is 60°C, the coarse oil residue is filtered out to obtain crude oil without coarse residue.

[0037] As some specific embodiments, step S2 can be repeated, that is, the fine oil residue in the crude oil is filtered out repeatedly to form a filter cake. The phospholipid content in the clear oil 200 is 0.9-1.1 mg / g.

[0038] As some specific embodiments, in step S2, when the phospholipid content in the crude oil after de-coarsening is 2.3-2.6 mg / g or 1.5-1.7 mg / g, or when the filter cake thickness is 7-12 mm, or when the filter cake density is 1.25-1.46 g / cm³, or when the filter cake oil content is 18%-23%, the original filter cake is removed, and the filtered fine oil residue is formed into a new filter cake, and when the fine oil residue is filtered out again, it is passed through the new filter cake.

[0039] It should be noted that if the crude oil residue in the raw material crude oil is not filtered and separated in step S1, when the raw material crude oil is filtered to form a filter cake in the later stage, the filter cake layer structure will be loose and easy to fall off, resulting in a low density of the filter cake, which will affect the realization and effect of phospholipid filtration of the raw material crude oil through the filter cake.

[0040] As some specific embodiments, in step S2, the fine oil residue in part of the crude oil with de-coarsened residue can be filtered out and then mixed with the rest of the crude oil with de-coarsened residue, and step S2 is repeated to obtain the clear oil 200. The mesh size of the fine oil residue can be 30-80 meshes.

[0041] As some specific embodiments, in step S2, the fine oil residue in part of the crude oil can be repeatedly filtered out to form a filter cake, and then the fine oil residue is filtered out of the crude oil through the filter cake; when the phospholipid content in the crude oil is 2.3-2.6 mg / g, the original filter cake is removed; and the fine oil residue in part of the crude oil with a phospholipid content of 2.3-2.6 mg / g is repeatedly filtered out to form a new filter cake, and then the fine oil residue is filtered out of the crude oil through the new filter cake.

[0042] Preferably, in step S2, when the temperature of the crude oil after de-coarsening is 60°C, the fine oil residue is filtered out to obtain the clear oil 200.

[0043] Preferably, in step S2, the crude oil after de-coarsening can be stirred so that the fine oil residue is suspended in the crude oil after de-coarsening. The fine oil residue can be granular or powdery. The mesh size of the fine oil residue can be 30-80 meshes. The mass percentage of the fine oil residue in the crude oil after de-coarsening can be 20-35%.

[0044] Preferably, in step S3, the temperature of the cooled clear oil may be 12-13°C.

[0045] Preferably, in step S4, the phospholipid content of the phospholipid-free oil may be 0.4-0.6 mg / g. Example

[0046] like Figure 2 As shown, a phospholipid anhydration removal device in crude oil can be used to implement the phospholipid anhydration removal method in crude oil as described in any one of Example 1, and the phospholipid anhydration removal device in crude oil comprises an oil clarifier 1, a residue filter 2, a cooler 3 and a filter 4. The oil clarifier 1 is used to add raw crude oil and filter out the coarse oil residue in the raw crude oil to obtain the crude oil without coarse residue. The residue filter 2 is used to filter out the fine oil residue in the crude oil without coarse residue to obtain clear oil 200. The cooler 3 is used to cool the clear oil 200 to obtain cooled clear oil. The filter 4 is used to filter the cooled clear oil to obtain the phospholipid-free oil.

[0047] In some embodiments, the oil clarifier 1 is provided with a scraper 201 for scooping out the coarse oil residue and stirring the fine oil residue to be suspended in the crude oil.

[0048] Specifically, the oil clarifier 1 is provided with a scraper conveyor, which drives and connects the scraper 201. The scraper conveyor can be a motor. The scraper conveyor performs a rotary motion. The scraper conveyor moves continuously, driving the scraper 201 to scrape up the coarse oil residue sunk to the bottom of the oil clarifier 1 and remove it, while stirring the fine oil residue in the crude oil in the oil clarifier 1 to be suspended.

[0049] In some embodiments, a filter grid plate may be provided on the oil clarifier 1, and filter holes may be provided on the filter grid plate. The filter holes may be rectangular holes, and the size may be 1.2×15 mm. The coarse oil residue removed by the scraper 201 in the oil clarifier 1 is scraped away on the filter grid plate, and the crude oil containing fine oil residues falls back into the oil clarifier 1 through the filter holes on the filter grid plate.

[0050] In some embodiments, the residue filter 2 is provided with an oil pump 202 for extracting the crude oil in the oil clarifier 1 and sending it to the residue filter 2 .

[0051] In some embodiments, the residue filter 2 includes a coarse residue filter 203 and a fine residue filter 204. The coarse residue filter 203 is used to filter out the fine oil residue in the coarse residue crude oil to obtain the refined residue crude oil 100; the fine residue filter 204 is used to filter out the fine oil residue in the refined residue crude oil 100 to obtain the clean oil 200.

[0052] In some embodiments, the filter residue machine 2 may be a plate filter, which is provided with a filter plate, and the filter plate may be a stainless steel screen, and the mesh number may be 60 meshes.

[0053] In some embodiments, the removal device further comprises an oil residue conveyor 5 for conveying and discharging the crude oil residue. The oil residue conveyor 5 may be a pipe chain conveyor.

[0054] Preferably, the oil pump 202 can be a gear-driven oil pump available in the prior art. The cooler 3 can be a freezing tank available in the prior art. The oil residue conveyor 5 can be a pipe chain conveyor available in the prior art.

[0055] Preferably, the filter 4 can be a plate-and-frame filter, including a frame, a filter layer installed in the frame, the filter layer includes one or both of filter cloth or filter paper, and the filter layer can be double-layered. The filter cloth can be cotton cloth. The filter cloth or filter paper is provided with filter pores. The density of the filter cloth can be 0.4-0.7 g / cm³, and the density of the filter paper can be 0.2 g / cm³.

[0056] Preferably, the specification of the filter cloth can be 2*5*10 or 2*2. 2*5*10 means that the warp of the filter cloth is composed of 2 wires with a wire diameter of 5 deniers, and the weft is composed of 1 wire with a wire diameter of 10 deniers. 2*2 means that the warp of the filter cloth is composed of 1 wire with a wire diameter of 2 deniers, and the weft is composed of 1 wire with a wire diameter of 2 deniers.

[0057] The method for removing phospholipids from crude oil by anhydration in this embodiment is implemented by using the device for removing phospholipids from crude oil by anhydration in this embodiment:

[0058] In step S1 , the crude oil can be transported to the oil clarifier 1 , and the scraper 201 of the oil clarifier 1 is continuously turned over on the oil clarifier 1 to remove the coarse oil residue in the crude oil and scrape it onto the filter grid of the oil clarifier 1 .

[0059] The coarse oil residue on the filter grid of the oil clarifier 1 can be pushed by the scraper 201 and fall into the oil residue conveyor 5, and then transported to the automatic residue removal machine through the oil residue conveyor 5, and after being deoiled by the automatic residue removal machine, it will be collected, discharged, and processed later.

[0060] In step S2, part of the crude oil with de-coarsened residue can be pumped into the crude oil filter 203 by the oil pump 202 of the crude oil filter 203, and the fine oil residue in the crude oil with de-coarsened residue in the crude oil filter 1 can be continuously turned and stirred by the scraper 201 of the oil clarifier 1; then the crude oil with de-coarsened residue is filtered through the filter plate of the crude oil filter 203, and at the same time, the fine oil residue that cannot pass through the filter plate is retained on the filter plate to form a filter cake, and the filter plate can easily retain the fine oil residue to form and place the filter cake; after the crude oil with de-coarsened residue is filtered through the filter cake, it becomes transparent and clear. It then flows back into the oil clarifier 1, is mixed with the rest of the crude oil removed from the oil clarifier 1, and is continuously pumped into the crude filter 203 by the oil pump 202 of the crude filter 203 for filtering the fine oil residue, thereby forming a closed loop for filtering the fine oil residue, and the cycle time may be 50-70 minutes, until the phospholipid content of the crude oil removed from the oil clarifier 1 is reduced to 2.3-2.6 mg / g, thereby obtaining the crude oil removed from the fine residue 100, that is, the phospholipid content of the crude oil removed from the fine residue 100 may be 2.3-2.6 mg / g.

[0061] When the filter cake thickness increases to 3mm, its structure becomes dense and fits tightly on the filter plate. As the filter cake thickness increases, it filters and retains more phospholipids in the crude oil.

[0062] In step 2, the crude oil after filtering the fine oil residue is returned to the oil clarifier 1, and mixed with the crude oil in the oil clarifier 1, when the phospholipid content of the crude oil in the oil clarifier 1 is 2.3-2.6 mg / g, the crude oil 100 is formed; then, the crude oil 100 in the oil clarifier 1 is extracted by the oil pump 202 of the fine residue filter 204, and the fine oil residue in the crude oil 100 is repeatedly filtered through the filter plate of the fine residue filter 204, and the fine oil residue that cannot pass through the filter plate is retained on the filter plate to form a filter cake; after the crude oil 100 is repeatedly filtered through the filter cake, the phospholipids therein are continuously retained by the filter cake to obtain the clear oil 200, and the phospholipid content of the clear oil 200 is 0.9-1.1 mg / g.

[0063] When the phospholipid content of the crude oil 100 is 1.5-1.7 mg / g, although the thickness of the filter cake is increasing and the pressure in the coarse filter 203 is also increasing, the phospholipid content of the crude oil is not changed.

[0064] When the pressure of the coarse filter 203 rises to 0.4Mpa, the filtration can be stopped, and the grease in the filter cakes of the coarse filter 203 and the fine filter 204 can be blown away by compressed air with an air pressure of 0.8Mpa. When the filter cake is white, it can be considered to be blown dry. At this time, the filter cake thickness can be 7-12mm, the filter cake density can be 1.25-1.46g / cm³, and the filter cake oil content can be 18%-23%. After the filter cake is removed by vibration by a vibrator, the fine oil residue can be intercepted by the filter plate again to form a new filter cake, and the coarse residue crude oil or fine residue crude oil 100 can be filtered through the new filter cake cycle, that is, enter the next filtering work cycle.

[0065] If the filter cake density is less than 0.9 g / cm³, the filter cake structure is loose and will break at the touch, and its phospholipid retention effect is poor.

[0066] In step S3, the clean oil 200 can be pumped into a freezing tank to be frozen and cooled to obtain cooled clean oil.

[0067] In step S4, the cooled clear oil can be filtered through a filter layer to obtain phospholipid-free oil.

[0068] In summary, the anhydrous removal method for phospholipids in crude oil of the present embodiment can limit the phospholipid content of the filtered raw material crude oil, that is, the phospholipid content of the raw material crude oil can be limited to less than 4.2 mg / g, or 3.4-4.2 mg / g; then the raw material crude oil can be removed from the coarse oil residue, and then filtered to remove the fine oil residue to obtain the crude oil 100 without fine residue; the crude oil 100 without fine residue can be mixed with the raw material crude oil, and continue to filter, so that the filtered fine oil residue is intercepted on the filter plate to form a filter cake; then the mixed crude oil 100 with the raw material crude oil is filtered through the filter cake, so that the phospholipids therein are intercepted and filtered by the filter cake, thereby reducing the phospholipid content therein; then the crude oil 100 without fine residue can be filtered again to obtain the clear oil 200, so that the phospholipids are further reduced; then the clear oil 200 is freeze-filtered to further reduce the phospholipids, and the phospholipids are finally obtained. The phospholipid-free oil is a finished qualified phospholipid oil.

[0069] Compared with the traditional phospholipid removal process, the anhydrous phospholipid removal method in crude oil does not require the addition of chemical reagents or water, avoids the loss of flavor substances in the oil during dehydration and distillation in the traditional process, and avoids the damage to the oil structure after adding chemicals. It can retain the original flavor of the oil, save production water, and avoid environmental pollution.

[0070] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0071] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for removing phospholipids from crude oil by anhydration, characterized in that: The phospholipid anhydration removal device in crude oil is used, and the phospholipid anhydration removal device in crude oil includes: The oil clarifier is used to add crude oil and filter out the coarse oil residue in the crude oil to obtain crude oil without coarse residue. The oil clarifier is provided with a scraper to remove the coarse oil residue and stir the fine oil residue in the crude oil to be suspended. The oil clarifier is provided with a filter grid plate, and the filter grid plate is provided with filter holes. The residue filter is used to filter out the fine oil residue in the coarse residue crude oil to obtain clean oil; the residue filter is provided with an oil pump to extract the raw material crude oil in the oil tank and send it to the residue filter; the residue filter is provided with a filter plate, and the filter plate is provided with filter holes, and the filter plate can intercept the fine oil residue to form and place a filter cake; the residue filter includes a coarse residue filter and a fine residue filter, and the coarse residue filter is used to filter out the fine oil residue in the coarse residue crude oil to obtain the fine residue crude oil; the fine residue filter is used to filter out the fine oil residue in the fine residue crude oil to obtain clean oil; Cooling machine, used to cool the clear oil, to obtain cooled clear oil, Filter, used to filter the cooling clear oil to obtain phospholipid-free oil, Oil residue conveyor, used to convey and discharge the coarse oil residue; The following steps are involved: Step S1, conveying the raw material crude oil to the oil clarifier, and filtering out the coarse oil residue in the raw material crude oil by continuously turning over the oil clarifier on the oil clarifier by means of a scraper of the oil clarifier, and scraping the coarse oil residue on the filter grid of the oil clarifier, scraping away the coarse oil residue removed by the scraper on the filter grid, and the coarse residue-removed crude oil containing fine oil residue falls back into the oil clarifier through the filter holes on the filter grid, thereby obtaining coarse residue-removed crude oil; the coarse oil residue on the filter grid of the oil clarifier continues to be pushed by the scraper, falls into the oil residue conveyor, and is then transported to the automatic residue removal machine by the oil residue conveyor, and is deoiled by the automatic residue removal machine for subsequent collection and discharge treatment; Step S2, firstly, part of the crude oil of the de-coarsened residue is pumped into the crude oil of the de-coarsened residue machine by the oil pump of the crude oil filter, and the fine oil residue in the crude oil of the de-coarsened residue in the crude oil of the oil clarifier is continuously turned and stirred by the scraper of the oil clarifier, so that the fine oil residue is suspended in the crude oil of the de-coarsened residue; then, the crude oil of the de-coarsened residue is filtered through the filter plate of the crude oil filter, and the fine oil residue in the crude oil of the de-coarsened residue is filtered out, and after the fine oil residue in part of the crude oil of the de-coarsened residue is filtered out, it is mixed with the rest of the crude oil of the de-coarsened residue, and step S2 is repeated to make the filtered oil unable to pass through The fine oil residue on the filter plate forms a filter cake on the filter plate, and the fine oil residue is filtered out through the filter cake; the fine oil residue is granular and powdery, and the fine oil residue is 30-80 mesh; when the phospholipid content in the crude oil is 2.3-2.6mg / g or 1.5-1.7mg / g, or when the filter cake thickness is 7-12mm, or when the filter cake density is 1.25-1.46g / cm³, or when the filter cake oil content is 18%-23%, remove the original filter cake and make the filtered fine oil residue form a new filter cake. The crude oil after de-coarsening becomes transparent and clear after being filtered through the filter cake, and then flows back to the oil clarifier, and after being mixed with the remaining crude oil after de-coarsening in the oil clarifier, it is continuously pumped into the crude filter through the oil pump of the coarse filter to filter the fine oil, thereby forming a closed-loop cycle for filtering the fine oil, and the cycle time is 50-70 minutes; until the phospholipid content of the crude oil after de-coarsening in the oil clarifier is reduced to 2.3-2.6 mg / g, the crude oil after de-coarsening is obtained. Then, the crude oil with fine residue in the oil tank is extracted by the oil pump of the fine residue filter, and the fine oil residue in the crude oil with fine residue is repeatedly filtered through the filter plate of the fine residue filter, and the fine oil residue that cannot pass through the filter plate is retained on the filter plate to form a filter cake; after the crude oil with fine residue is repeatedly filtered through the filter cake, the phospholipids therein are continuously retained by the filter cake, and when the temperature of the crude oil with coarse residue is 60°C, the fine oil residue therein is filtered out to obtain clear oil, and the phospholipid content in the clear oil is 0.9-1.1mg / g; Step S3, pumping the clear oil into a freezing tank, freezing and cooling the clear oil to a temperature of 12-13° C., and obtaining cooled clear oil. Step S4, filtering the cooled clear oil through a filter layer to obtain phospholipid-free oil; the filter layer includes a filter cloth, the filter layer is a double layer, and the density of the filter cloth is 0.4-0.7 g / cm³; the specification of the filter cloth is 2*2, and the warp thread for weaving the filter cloth is composed of 1 thread with a wire diameter of 2 deniers, and the weft thread is composed of 1 thread with a wire diameter of 2 deniers.

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