Alkali refining deacidification and nigre desolventizing system for cottonseed mixed oil

Abstract

The utility model discloses a cottonseed mixed oil alkali refining deacidification and nigre desolventizing system which is characterized in that an outlet of a mixed oil tank is connected with a tube pass inlet of a first evaporator, an oil outlet of the first evaporator is connected with a thick mixed oil tank, and an outlet of the thick mixed oil tank is connected with an alkali reaction tank through an alkali dynamic mixer and a plurality of static mixers; an outlet of the alkali reaction tank is connected with an inlet of the soap removal centrifugal machine through a soap removal separation feeding pump; a light phase outlet of the de-soaping centrifuge is connected with a tube pass inlet of a second evaporator through a cold side of a mixed oil heat exchanger, an oil outlet of the second evaporator is connected with an upper inlet of a stripping tower, and a bottom outlet of the stripping tower is connected with an oil inlet of an acid dynamic mixer through a hot side of the mixed oil heat exchanger; an outlet of the acid dynamic mixer is connected with the washing reaction tank; an outlet of the washing reaction tank is connected with an inlet of the washing centrifuge, and a light-phase outlet of the washing centrifuge is connected with a finished oil outlet pipe. According to the system, steam consumption and soap content of third-level oil are reduced, and comprehensive utilization of alkali refining wastewater is realized.

Description

Technical Field

[0001] The utility model relates to an oil refining system, in particular to an alkali refining, deacidification and soapstock desolventizing system for cottonseed mixed oil, belonging to the technical field of vegetable oil refining. Background Art

[0002] Cottonseed contains high oil content and can be pressed for oil. It is an important edible oil and industrial oil. Cottonseed cake can be used as feed for livestock. Deep processing of cottonseed processing byproducts can be used to extract cottonphenol, cotton protein feed, cottonseed sugar, xylitol, etc. Cottonseed oil is a semi-drying oil. Unrefined cottonseed crude oil has a sour and astringent taste and a darker color. The appearance is brown or dark brown. The color of crude oil is mainly caused by the presence of cottonphenol and its derivatives, pigments, etc. in the oil. The presence of free fatty acids makes the crude oil sour and astringent. These components must be removed during the oil refining process, otherwise they will affect the flavor and sensory indicators of cottonseed oil. Cottonphenol is a unique component in cottonseed crude oil. Cottonphenol and its derivatives are strong pigments; the cottonphenol in crude oil gives cottonseed crude oil red to brown characteristics.

[0003] Alkali refining and bleaching are two steps to reduce the color of crude oil. If the alkali refining section cannot completely remove the cottonpol, the cottonpol that has not been completely removed will denature and fix the color when the temperature rises during the bleaching and deodorization, resulting in an irremovable color. Therefore, the alkali refining section is the key to removing cottonpol. In order to obtain high-quality cottonseed oil, the cottonpol must be reduced to a minimum in the alkali refining section. The principle of removing free cottonpol during alkali refining of cottonseed oil is that the free cottonpol contained in the crude cottonseed oil can react with alkali to become phenol salt. This phenol salt is more easily adsorbed and precipitated by soap stock during the alkali refining process, thereby reducing the color of the cottonseed oil and improving the quality of refined cottonseed oil.

[0004] The cottonseed mixed oil alkali refining process is a new technology promoted and applied in China. It is a refining process carried out in the mixed oil state in the leaching workshop. The advantages of mixed oil alkali refining are: compared with traditional refining, the mixed oil has a low viscosity and a high soap stock specific gravity, which has a better separation effect during centrifugal separation, and ultimately a higher cottonseed oil refining yield can be obtained. The mixed oil alkali refining removes cottonpol before passing through the second evaporator, avoiding the situation where cottonpol is difficult to remove after being exposed to high temperatures; in addition, the mixed oil enters the second evaporator after alkali refining, which reduces the scaling of the mixed oil heat exchanger and the second evaporator and extends the cleaning cycle.

[0005] The Chinese invention patent with the announcement number CN 107641556B discloses a method for continuous alkali refining and deacidification of cottonseed oil. The cottonseed mixed oil and alkali solution are heated to 40-60°C respectively, and atomized by a high-pressure atomizing nozzle, so that the cottonseed mixed oil droplets and the alkali solution droplets collide at high speed to carry out a neutralization reaction. The high-pressure atomizing nozzles on both sides of the secondary neutralization tank are passed into the secondary neutralization tank, and the oil droplets and the alkali solution droplets collide at high speed to carry out a secondary neutralization reaction. The deacidified oil obtained by the reaction flows out from the overflow port of the secondary neutralization tank and enters the storage tank. The soap stock obtained by the reaction is discharged from the bottom of the secondary neutralization tank and enters the soap liquid tank; the obtained deacidified oil is subjected to conventional desolventizing operation to obtain the refined cottonseed oil product. The disadvantage of this method is that the soap stock and the deacidified oil are separated by natural sedimentation, the separation efficiency is low, and the product cannot meet the requirement of the soap content of the national standard for grade tertiary oil to be less than 100ppm. In addition, the separated soap liquid still contains a large amount of solvent, and lacks the corresponding soap stock desolventizing step.

[0006] The utility model patent with the announcement number CN 215799397U discloses a soap stock desolventizing system, which has the advantages of low steam consumption, low power consumption, low equipment maintenance cost, and low soap stock residual dissolution. However, in the actual operation process, the liquid flooding phenomenon occurs, and the soap stock is entrained into the water separation tank, affecting the normal operation of the water separation tank. In addition, the system does not take into account the soap stock desolventizing and mixed oil alkali refining as a whole. Although the soap stock desolventizing process itself does not generate wastewater, it does not make full use of the wastewater generated in the mixed oil washing process. Utility Model Content

[0007] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and utility model name of this application to avoid blurring the purpose of this section, specification abstract and utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0008] In view of the above and / or existing problems in the prior art of high steam consumption, low yield, high soap content in tertiary oil, unstable operation, difficulty in desolventizing soapstock and comprehensive utilization of wastewater in the alkali refining process of cottonseed oil, the utility model is proposed.

[0009] The purpose of the utility model is to overcome the problems existing in the prior art and provide a cottonseed mixed oil alkali refining deacidification and soap stock desolventizing system, which simplifies the process flow, ensures safe and stable production, reduces steam consumption and the soap content of tertiary oil, and realizes the comprehensive utilization of alkali refining wastewater.

[0010] In order to solve the above technical problems, the utility model discloses a cottonseed mixed oil alkali refining deacidification and soap stock desolventizing system, comprising a mixed oil tank, the outlet of the mixed oil tank is connected to the tube inlet of the first evaporator through a steam feed pump, the oil outlet of the first evaporator is connected to the concentrated mixed oil tank through a steam extraction pump, the outlet of the concentrated mixed oil tank is connected to the oil inlet of the alkali dynamic mixer through the alkali refining feed pump, the outlet of the alkali dynamic mixer is connected to the alkali reaction tank through a plurality of static mixers, and the outlet of the alkali reaction tank is connected to the inlet of the soap removal centrifuge through the soap removal separation feed pump;

[0011] The light phase outlet of the desoaping centrifuge is connected to the tube side inlet of the second evaporator through the cold side of the mixed oil heat exchanger, the oil outlet of the second evaporator is connected to the upper inlet of the stripping tower through the second steam extraction pump, the bottom outlet of the stripping tower is connected to the oil inlet of the acid dynamic mixer through the stripping extraction pump and the hot side of the mixed oil heat exchanger, and the outlet of the acid dynamic mixer is connected to the water washing reaction tank; the outlet of the water washing reaction tank is connected to the inlet of the water washing centrifuge through the water washing separation feeding pump, and the light phase outlet of the water washing centrifuge is connected to the finished oil outlet pipe.

[0012] Furthermore, the light phase outlet of the water washing centrifuge is connected to the cold side of the water washing oil heater and the inlet of the dryer via the cold side of the oil-to-oil heat exchanger in sequence, the outlet of the dryer is connected to the hot side inlet of the oil-to-oil heat exchanger via the finished oil extraction pump, and the hot side outlet of the oil-to-oil heat exchanger is connected to the finished oil outlet pipe via the hot side of the finished oil cooler.

[0013] Furthermore, the dense phase outlet of the water washing centrifuge is connected to the inlet of the oil-water separation box, and the oil outlet of the oil-water separation box is connected to the oil return port of the concentrated mixed oil tank via an oil recovery pump.

[0014] Furthermore, the water outlet of the oil-water separation box is connected to the middle spray port of the soapstock desolventizer via a washing water extraction pump.

[0015] Furthermore, the dense phase outlet of the soap desolventizing centrifuge is connected to a soapstock tank, the outlet of the soapstock tank is connected to a pipe side inlet of a soapstock heater via a soapstock delivery pump containing solvent, and the pipe side outlet of the soapstock heater is connected to an upper spray port of the soapstock desolventizer.

[0016] Furthermore, the bottom outlet of the soapstock desolventizer is connected to the lower spray port of the soapstock desolventizer through a soapstock circulation pump; the bottom outlet of the soapstock desolventizer is also connected to a soapstock outlet pipe through a soapstock extraction pump.

[0017] Furthermore, the top outlet of the soapstock desolventizer is connected to the inlet of the liquid-foam separator, the upper outlet of the liquid-foam separator is connected to the shell-side inlet of the soapstock desolventizer condenser, and the shell-side outlet of the soapstock desolventizer condenser is discharged through the desolventizing condensation exhaust pipe; the shell-side drain port of the soapstock desolventizer is connected to the inlet of the water separation tank, the overflow port of the water separation tank is connected to the solvent outlet pipe, and the bottom drain port of the water separation tank is connected to the return water port of the soapstock desolventizer.

[0018] Compared with the prior art, the utility model has achieved the following beneficial effects: 1. In the first evaporator, the gas phase of the de-steaming machine is used to concentrate the mixed oil, which greatly saves the steam consumption of the second evaporator; an efficient sieve plate stripping tower is used to desolventize the mixed oil after soap removal, which can control the cottonseed tertiary oil content to be below 20ppm, thereby ensuring the quality of the tertiary oil. Compared with the traditional disc-type stripping tower, the sieve plate stripping tower can save more than 30% of steam consumption; an efficient sieve plate stripping tower is used to desolventize the mixed oil after soap removal, which can control the cottonseed tertiary oil content to be below 20ppm, thereby ensuring the quality of the tertiary oil. Compared with the traditional disc-type stripping tower, the sieve plate stripping tower can save more than 30% of steam consumption, etc.; heat energy recovery is maximized, saving more than 10kg of steam for every ton of cottonseed processed;

[0019] 2. Before the mixed oil enters the alkali reaction, the concentration of the mixed oil is automatically monitored and controlled to ensure the consistency of the concentration of the mixed oil entering the alkali refining; before the mixed oil enters the alkali reaction, a shell and tube heater with steam and circulating water is used to control the temperature, and the reaction temperature of the mixed oil alkali refining is stably controlled between 55-58°C. After the mixed oil is alkali-refined, the impurities in the mixed oil are removed to the maximum extent, avoiding the scaling of the mixed oil heat exchanger and the second evaporator. Because the scaling phenomenon is eliminated, the existing shell and tube heat exchanger can be changed to a plate heat exchanger to improve the heat recovery effect.

[0020] 3. After the cottonseed mixed oil and liquid alkali are dynamically mixed, multiple static mixers are used to further delay the mixing of the mixed oil and alkali, which greatly shortens the residence time of the mixed oil in the alkali reactor. Thanks to the intensification of the alkali reaction, the volume of the alkali reactor can be reduced and the acidification section in the traditional mixed oil alkali refining process can be eliminated, simplifying the process and reducing equipment investment.

[0021] 4. Through the online control system and efficient reaction and separation process, the oil content of soap stock dry basis is reduced to 10-15%, and the cottonseed oil yield is increased by 0.5-1.0%;

[0022] 5. The produced third-grade cottonseed oil has been decolorized for many times, which saves the secondary alkali refining and water washing compared with the traditional cottonseed oil decolorization, and has a strong thermal decolorization effect in the deodorization section;

[0023] 6. The soap content of cottonseed grade 3 oil has been reduced from the current 100ppm to below 10ppm, the residual solvent of cottonseed grade 3 oil has been reduced from the current 100ppm to below 20ppm, and the residual solvent of soap stock has been reduced from the current 3000ppm to below 200ppm, which is far better than the national standard;

[0024] 7. The circulating jet desolventizing system is used to recover the solvent from soap stock. A water capture device is added in the middle to effectively control the flooding phenomenon during the desolventizing process and control the residual solvent in soap stock below 100ppm. The capture water used by the device can all be the washing water generated during the cottonseed oil washing process, and all the wastewater in the alkali refining process can be reused, achieving zero wastewater discharge in the cottonseed oil alkali refining process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. The drawings are only provided for reference and explanation, not for limiting the present utility model. Among them:

[0026] Figure 1 This is a flow chart of the utility model cottonseed mixed oil alkali refining deacidification and soap stock desolventizing system;

[0027] In the figure: T1. Mixing oil tank; T2: Concentrated mixed oil tank; T3. Liquid alkali tank; T4. Alkali reaction tank; T5. Water washing reaction tank; T6. Dryer; T7. Oil-water separation box; T8. Soap stock tank; T9. Soap stock desolventizer; T10. Liquid-foam separator; T11. Water separation tank;

[0028] E1. First evaporator; E2. Mixed oil heater / cooler; E3: Mixed oil heat exchanger; E4. Second evaporator; E5. Wash oil heater; E6. Oil-to-oil heat exchanger; E7: Finished oil cooler; E8: Soap stock heater; E9. Soap stock desolventizing condenser;

[0029] P1. First steam feed pump; P2. First steam extraction pump; P3. Alkali refining feed pump; P4. Alkali metering pump; P5. Soap removal separation feed pump; P6. Second steam extraction pump; P7. Steam stripping extraction pump; P8. Water washing separation feed pump; P9. Finished oil extraction pump; P10. Oil recovery pump; P11. Washing water extraction pump; P12. Soap stock delivery pump; P13. Soap stock circulation pump; P14. Soap stock extraction pump;

[0030] SMX1-7. The first to seventh static mixers; DMX1. Alkali dynamic mixer; DMX2. Acid dynamic mixer;

[0031] S1. Soap removal centrifuge; S2. Water washing centrifuge; OS1. Stripping tower;

[0032] G1. Thin mixed oil inlet pipe; G2. Finished oil outlet pipe; G3. Soap stock outlet pipe; G4: Solvent outlet pipe; G5. First steam exhaust pipe; G6. Second steam exhaust pipe; G7. Stripping exhaust pipe; G8. Dryer exhaust pipe; G9. Liquid alkali pipe; G10. Acid pipe; G11. Hot water pipe; G12. First steam phase inlet pipe; G13. First steam condensate pipe; G14. Raw steam pipe; G15. Steam condensate water collection pipe; G16. Circulating water inlet pipe; G17. Circulating water outlet pipe; G18. Desolventizing condensation exhaust pipe; G19. Mixed oil concentration adjustment pipe. DETAILED DESCRIPTION

[0033] In the following description of the utility model, the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a specific direction.

[0034] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0036] like Figure 1As shown, the cottonseed mixed oil alkali refining deacidification and soap stock desolventizing system of the utility model comprises a mixed oil tank T1, a concentrated mixed oil tank T2, a liquid alkali tank T3, an alkali reaction tank T4, a water washing reaction tank T5, a dryer T6, an oil-water separation box T7, a soap stock tank T8 and a soap stock desolventizer T9, etc. The outlet of the mixed oil tank T1 is connected to the pipe side inlet of the first evaporator E1 through a steam feed pump P1, the top outlet of the first evaporator E1 is connected to a steam exhaust pipe G5, the oil outlet of the first evaporator E1 is connected to the inlet of a steam extraction pump P2, the outlet of the steam extraction pump P2 is connected to the inlet of the first static mixer SMX1, the outlet of the mixed oil concentration adjusting pipe G19 is also connected to the inlet of the first static mixer SMX1, and the inlet of the mixed oil concentration adjusting pipe G19 is connected to the crude oil pipe and the solvent pipe, so as to adjust the concentration of the mixed oil. The outlet of the first static mixer SMX1 is connected to the concentrated mixed oil tank T2, the outlet of the concentrated mixed oil tank T2 is connected to the pipe side inlet of the mixed oil heater / cooler E2 via the alkali refining feed pump P3, the pipe side outlet of the mixed oil heater / cooler E2 is connected to the oil inlet of the alkali dynamic mixer DMX1; the shell side upper end interface of the mixed oil heater / cooler E2 is connected to the raw steam pipe G14 and the circulating water inlet pipe G16, and the shell side lower end interface of the mixed oil heater / cooler E2 is connected to the steam condensate collection pipe G15 and the circulating water outlet pipe G17.

[0037] The liquid alkali pipe G9 is connected to the liquid alkali tank T3, the bottom outlet of the liquid alkali tank T3 is connected to the inlet of the alkali metering pump P4, the outlet of the alkali metering pump P4 and the outlet of the hot water pipe G11 are connected to the inlet of the seventh static mixer SMX7, and the outlet of the seventh static mixer SMX7 is connected to the upper inlet of the side wall of the alkali dynamic mixer DMX1. The outlet of the alkali dynamic mixer DMX1 is connected to the alkali reaction tank T4 through the second static mixer SMX2 to the sixth static mixer SMX6 connected in series, and the outlet of the alkali reaction tank T4 is connected to the inlet of the desoaping centrifuge S1 through the desoaping separation feeding pump P5.

[0038] The cold side of the mixed oil heat exchanger E3 at the light phase outlet of the desoaping centrifuge S1 is connected to the tube side inlet of the second evaporator E4, the shell side inlet of the second evaporator E4 is connected to the raw steam pipe G14, and the shell side outlet of the second evaporator E4 is connected to the steam condensate collecting pipe G15; the top outlet of the second evaporator E4 is connected to the secondary steam exhaust pipe G6; the oil outlet of the second evaporator E4 is connected to the upper inlet of the stripping tower OS1 through the secondary steam extraction pump P6, and the top outlet of the stripping tower OS1 is connected to the stripping exhaust pipe G7. The bottom outlet of the stripping tower OS1 is connected to the oil inlet of the acid dynamic mixer DMX2 via the stripping extraction pump P7 and the hot side of the mixed oil heat exchanger E3, and the outlet of the acid dynamic mixer DMX2 is connected to the inlet of the water washing reaction tank T5; the outlets of the acid liquid pipe G10 and the hot water pipe G11 are also connected to the inlet of the water washing reaction tank T5, and the outlet of the water washing reaction tank T5 is connected to the inlet of the water washing centrifuge S2 via the water washing separation feeding pump P8, and the light phase outlet of the water washing centrifuge S2 is connected to the finished oil outlet pipe G2.

[0039] The light phase outlet of the water washing centrifuge S2 is connected to the cold side of the oil-oil heat exchanger E6 and the cold side of the water washing oil heater E5 and the inlet of the dryer T6 in turn, the top outlet of the dryer T6 is connected to the dryer exhaust pipe G8, the outlet of the dryer T6 is connected to the hot side inlet of the oil-oil heat exchanger E6 through the finished oil extraction pump P9, and the hot side outlet of the oil-oil heat exchanger E6 is connected to the finished oil outlet pipe G2 through the hot side of the finished oil cooler E7.

[0040] The dense phase outlet of the water washing centrifuge S2 is connected to the inlet of the oil-water separation box T7, and the oil outlet of the oil-water separation box T7 is connected to the oil return port of the concentrated mixed oil tank T2 through the oil recovery pump P10.

[0041] The water outlet of the oil-water separation box T7 is connected to the middle spray port of the soap stock desolventizer T9 through the washing water extraction pump P11.

[0042] The dense phase outlet of the soap desolventizing centrifuge S1 is connected to the soapstock tank T8, the outlet of the soapstock tank T8 is connected to the tube side inlet of the soapstock heater E8 through the soluble soapstock delivery pump P12, and the tube side outlet of the soapstock heater E8 is connected to the upper spray port of the soapstock desolventizer T9.

[0043] The bottom outlet of the soapstock desolventizer T9 is connected to the lower spray port of the soapstock desolventizer T9 through a soapstock circulation pump P13; the bottom outlet of the soapstock desolventizer T9 is also connected to the soapstock outlet pipe G3 through a soapstock extraction pump P14.

[0044] The top outlet of the soapstock desolventizer T9 is connected to the inlet of the liquid-foam separator T10, the upper outlet of the liquid-foam separator T10 is connected to the shell-side inlet of the soapstock desolventizer E9, and the shell-side outlet of the soapstock desolventizer E9 is discharged through the desolventizing condensation exhaust pipe G18; the shell-side outlet of the soapstock desolventizer E9 is connected to the desolventizing condensation exhaust pipe G18, the shell-side drain port of the soapstock desolventizer E9 is connected to the inlet of the water separation tank T11, the overflow port of the water separation tank T11 is connected to the solvent outlet pipe G4, and the bottom drain port of the water separation tank T11 is connected to the return water port of the soapstock desolventizer T9.

[0045] The mixed oil with a concentration of 25% from the extractor enters the mixed oil tank T1 from the thin mixed oil inlet pipe G1. The mixed oil in the mixed oil tank T1 is sent to the tube side of the first evaporator E1 through a steam feed pump P1. The first evaporator E1 is a rising film evaporator, the shell side is the hot side, and the steam phase of the steam evaporator at about 75°C is used as the heat source. It enters the shell side of the first evaporator E1 through a vapor phase inlet pipe G12, and the first evaporation condensate is discharged from the first evaporation condensate pipe G13 into the water distribution tank.

[0046] The tube vacuum of the first evaporator E1 is controlled at -60KPa, which can increase the concentration of the mixed oil to 85% and the temperature to 55-60℃. The concentrated mixed oil is sent to the concentrated mixed oil tank T2 through the first evaporator extraction pump P2. The first evaporator mixed oil is equipped with a concentration detector and an automatic concentration adjustment valve before entering the concentrated mixed oil tank T2. When the concentration of the mixed oil is low, crude oil can be automatically added to the mixed oil; when the concentration of the mixed oil is high, solvent can be automatically added to the mixed oil to ensure the consistency of the concentration of the mixed oil when entering the alkali refining.

[0047] The mixed oil in the concentrated mixed oil tank T2 is sent to the mixed oil heater / cooler E2 through the alkali refining feed pump P3 to stably control the temperature of the mixed oil at 55°C. The mixed oil heater / cooler E2 uses both steam and circulating water. When the mixed oil temperature is higher than 55°C, the circulating water is used to cool the mixed oil; when the mixed oil temperature is lower than 55°C, steam is used to heat the mixed oil.

[0048] Liquid alkali with a mass concentration of about 30% enters the liquid alkali tank T3 from the liquid alkali pipe G9, and the liquid alkali is output through the alkali metering pump P4, hot water is added online, and mixed in the seventh static mixer SMX7 to control the concentration of the liquid alkali at 18 degrees Baume. An automatic online alkali preparation system is used to stably control the concentration and flow of the liquid alkali, avoiding excessive or insufficient liquid alkali during the reaction. The prepared liquid alkali is mixed with the mixed oil at the outlet of the mixed oil heater / cooler E2 in the alkali dynamic mixer DMX1, and after mixing, it enters the second static mixer SMX2 to the sixth static mixer SMX6 for further reaction. Then the mixed oil finally enters the alkali reactor T4, the mixed oil and alkali react in the reactor alkali reactor T4 with a delayed reaction, the fatty acid and the alkali react to form soap by neutralization, and the soap adsorbs the formed phenol salt to form flocculants.

[0049] The mixed oil and soap stock are sent to the desoap centrifuge S1 by the desoap separation feed pump P5. The desoap centrifuge S1 is a disc centrifuge, which can be separated into two phases, heavy phase and light phase, according to the difference in density. The heavy phase is soap stock, which enters the soap stock tank T8. The light phase at the outlet of the desoap centrifuge is the mixed oil. After entering the cold side heat exchange of the mixed oil heat exchanger E3, the temperature reaches 85℃, and then the mixed oil enters the second evaporator E4. Like the first evaporator E1, the second evaporator E4 is also a rising film evaporator. The shell side is heated by fresh steam. The concentration of the mixed oil at the outlet of the second evaporator E4 is 97% and the temperature is 105℃. The mixed oil at the outlet of the second evaporator E4 is transported to the stripping tower OS1 through the second steam extraction pump P6. The stripping tower OS1 is a sieve plate tower. The oil enters from the top of the tower and the steam enters from the bottom of the tower. In the process of countercurrent contact, the solvent in the mixed oil is removed. The removed solvent and water vapor enter the stripping condenser from the stripping exhaust pipe G7. The residual cottonseed oil at the outlet of the stripping tower OS1 is less than 20ppm, and the temperature is 100℃. After being sent to the hot side of the mixed oil heat exchanger E3 by the stripping extraction pump P7, it enters the acid dynamic mixer DMX2. In the acid dynamic mixer DMX2, the amount of phosphoric acid added is 0.01% and the amount of hot water added is 3%. The mixed cottonseed oil enters the water washing reactor T5, and then is transported to the water washing centrifuge S2 by the water washing separation feed pump P8. The water washing centrifuge S2 is a disc centrifuge, which can be separated into a heavy phase and a light phase according to the difference in density. The heavy phase is the washing water, which enters the oil-water separation tank T7. In the oil-water separation tank T7, the incompatible oil and water are separated under the action of the density difference. The oil has a small density and enters the oil temporary storage part from the upper layer, and then is transported to the concentrated mixed oil tank T2 by the oil recovery pump P10. The water has a large density and overflows from the bottom into the water temporary storage part, and is then transported out through the wash water extraction pump P11 as the captured water of the soapstock desolventizer T9.

[0050] The light phase of the water washing centrifuge S2 is cottonseed oil. After entering the cold side of the oil-oil heat exchanger E6 and heating it to 90°C, it is heated to 105°C by the water washing oil heater E5 and enters the dryer T6. The dryer works under a vacuum of -90kpa and can reduce the moisture content in the cottonseed oil from 0.5% to below 0.05%. The dried cottonseed oil is transported to the hot side of the oil-oil heat exchanger E6 by the finished oil extraction pump P9, and then cooled to 40°C by the finished oil cooler E7 and enters the finished oil tank from the finished oil outlet pipe G2. The soap content of the finished oil is controlled below 10ppm.

[0051] The soap stock in the soap stock tank T8 has a temperature of 55°C, a solvent content of 12000ppm, and a dry basis oil content of 15%. The soap stock is transported to the cold side of the soap stock heater E8 by the solvent-containing soap stock delivery pump P12, and then enters the soap stock desolventizer T9 after being heated to 85°C. When entering the soap stock desolventizer T9, the soap stock is sprayed into fine droplets in the soap stock desolventizer under the action of fresh steam G14, and the solvent in the soap stock is continuously exposed to the gas phase space and gasified and separated. The soap stock that falls to the bottom of the soap stock desolventizer T9 still contains a small amount of solvent. Under the action of the soap stock circulation pump P13, it is lifted to the middle of the soap stock desolventizer T9 again for flash separation. The solvent separated from the soap stock desolventizer T9 enters the liquid-foam separator T10 together with the water vapor, and the separated liquid foam automatically flows back to the soap stock desolventizer T9, and the separated gas phase enters the soap stock desolventizer condenser E9. The condensate from the soapstock desolventizing condenser E9 enters the water separation tank T11, the separated water overflows back to the soapstock desolventizing condenser T9, and the separated solvent flows back to the water separation tank from the solvent outlet pipe G4 for recycling again.

[0052] During operation, soap stock desolventizer T9 is used to continuously bubble upward in the presence of soap, and when it reaches the middle, it is sprayed and captured with washing water from soap stock delivery pump P12 to eliminate the foam. The soap stock after desolventization contains 100ppm of solvent, and is sent to the soap stock tank through soap stock extraction pump P14 and soap stock outlet pipe G3.

[0053] The above description is only the preferred feasible embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model, but does not limit the scope of patent protection of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments. In addition to the above embodiments, the utility model can also have other implementation modes without departing from the spirit and scope of the utility model. The utility model will also have various changes and improvements. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The scope of protection required by the utility model is defined by the attached claims and their equivalents. The technical features not described in the utility model can be achieved by or using existing technologies, which will not be repeated here.

Claims

1. A cottonseed mixed oil alkali refining, deacidification and soap stock desolventizing system, comprising a mixed oil tank (T1), characterized in that: The outlet of the mixed oil tank (T1) is connected to the pipe side inlet of the first evaporator (E1) through a steam feed pump (P1), the oil outlet of the first evaporator (E1) is connected to the concentrated mixed oil tank (T2) through a steam extraction pump (P2), the outlet of the concentrated mixed oil tank (T2) is connected to the oil inlet of the alkali dynamic mixer (DMX1) through an alkali refining feed pump (P3), the outlet of the alkali dynamic mixer (DMX1) is connected to the alkali reaction tank (T4) through a plurality of static mixers, and the outlet of the alkali reaction tank (T4) is connected to the inlet of the soap removal centrifuge (S1) through a soap removal separation feed pump (P5); The light phase outlet of the desoaping centrifuge (S1) is connected to the tube side inlet of the second evaporator (E4) via the cold side of the mixed oil heat exchanger (E3); the oil outlet of the second evaporator (E4) is connected to the upper inlet of the stripping tower (OS1) via the second steam extraction pump (P6); the bottom outlet of the stripping tower (OS1) is connected to the oil inlet of the acid dynamic mixer (DMX2) via the stripping extraction pump (P7) and the hot side of the mixed oil heat exchanger (E3); the outlet of the acid dynamic mixer (DMX2) is connected to the water washing reaction tank (T5); the outlet of the water washing reaction tank (T5) is connected to the inlet of the water washing centrifuge (S2) via the water washing separation feeding pump (P8); the light phase outlet of the water washing centrifuge (S2) is connected to the finished oil outlet pipe (G2).

2. The cottonseed mixed oil alkali refining, deacidification and soapstock desolventizing system according to claim 1, characterized in that: The light phase outlet of the water washing centrifuge (S2) is connected to the cold side of the water washing oil heater (E5) and the inlet of the dryer (T6) in sequence through the cold side of the oil-oil heat exchanger (E6); the outlet of the dryer (T6) is connected to the hot side inlet of the oil-oil heat exchanger (E6) through the finished oil extraction pump (P9); the hot side outlet of the oil-oil heat exchanger (E6) is connected to the finished oil outlet pipe (G2) through the hot side of the finished oil cooler (E7).

3. The cottonseed mixed oil alkali refining, deacidification and soapstock desolventizing system according to claim 1, characterized in that: The dense phase outlet of the water washing centrifuge (S2) is connected to the inlet of the oil-water separation box (T7), and the oil outlet of the oil-water separation box (T7) is connected to the oil return port of the concentrated mixed oil tank (T2) via an oil recovery pump (P10).

4. The cottonseed mixed oil alkali refining, deacidification and soapstock desolventizing system according to claim 3, characterized in that: The water outlet of the oil-water separation box (T7) is connected to the middle spray port of the soap stock desolventizer (T9) via a washing water extraction pump (P11).

5. The cottonseed mixed oil alkali refining, deacidification and soapstock desolventizing system according to claim 4, characterized in that: The dense phase outlet of the soap desolventizing centrifuge (S1) is connected to a soapstock tank (T8), the outlet of the soapstock tank (T8) is connected to a pipe side inlet of a soapstock heater (E8) via a soapstock delivery pump (P12), and the pipe side outlet of the soapstock heater (E8) is connected to an upper spray port of the soapstock desolventizer (T9).

6. The cottonseed mixed oil alkali refining, deacidification and soapstock desolventizing system according to claim 5, characterized in that: The bottom outlet of the soapstock desolventizer (T9) is connected to the lower spray port of the soapstock desolventizer (T9) through a soapstock circulation pump (P13); the bottom outlet of the soapstock desolventizer (T9) is also connected to a soapstock outlet pipe (G3) through a soapstock extraction pump (P14).

7. The cottonseed mixed oil alkali refining, deacidification and soapstock desolventizing system according to claim 5, characterized in that: The top outlet of the soapstock desolventizer (T9) is connected to the inlet of the liquid-foam separator (T10), the upper outlet of the liquid-foam separator (T10) is connected to the shell-side inlet of the soapstock desolventizer (E9), and the shell-side outlet of the soapstock desolventizer (E9) is discharged through a desolventizing condensation exhaust pipe (G18); the shell-side liquid discharge port of the soapstock desolventizer (E9) is connected to the inlet of a water separation tank (T11), the overflow port of the water separation tank (T11) is connected to the solvent outlet pipe (G4), and the bottom drain port of the water separation tank (T11) is connected to the water return port of the soapstock desolventizer (T9).

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