Leached mixed oil evaporation system

Abstract

The utility model discloses a leached mixed oil evaporation system which is characterized in that an outlet of a mixed oil input pipe is connected with a tube pass inlet of a mixed oil preheater, a tube pass outlet of the mixed oil preheater is connected with an oil inlet of a pre-first evaporation flash tank, and an oil outlet of the pre-first evaporation flash tank is connected with a shell pass inlet of an oil-oil heat exchanger through a pre-first evaporation extraction pump; a shell pass outlet of the oil-oil heat exchanger is connected with an oil inlet of the first evaporator, an oil outlet of the first evaporator is connected with an oil inlet of the pre-second evaporator through a first evaporator extraction pump, the first evaporator and the pre-second evaporator are falling film evaporators, and an oil outlet of the pre-second evaporator is connected with an oil inlet of the second evaporator through a pre-second evaporator extraction pump. The second evaporator is a climbing film evaporator, an oil outlet of the second evaporator is connected with an oil inlet of the stripping tower, an oil outlet of the stripping tower is connected with a tube pass inlet of the oil-oil heat exchanger through a stripping tower extraction pump, and a tube pass of the oil-oil heat exchanger is connected with a crude oil output tube. The system can improve the heat energy recovery efficiency, reduce steam consumption and reduce the load of the condensation system.

Description

Technical Field

[0001] The utility model relates to an evaporation system, in particular to a leaching miscella evaporation system, belonging to the technical field of evaporation equipment. Background Technique

[0002] The oil extraction by leaching method has a history of more than a hundred years and is applicable to most oilseeds for oil extraction, especially those oil raw materials with high nutritional value but low oil yield. It mainly includes an extraction section, a wet meal desolventizing section, a miscella evaporation section, and a tail gas absorption section.

[0003] In a conventional miscella evaporation section, the main equipment includes a first evaporator, an oil-oil heat exchanger, a second evaporator, a stripping tower, and a crude oil cooler. It is a full negative pressure evaporation with a low evaporation temperature and high oil quality. The vacuum system often uses a steam jet pump. Specifically as follows: The miscella is heated and flash-evaporated in the first evaporator, and the outlet miscella concentration reaches ~80%, and the temperature is ~55°C. A rising film evaporator is mostly used with high heat transfer efficiency; the miscella at the outlet of the first evaporator exchanges heat with the crude oil at the outlet of the stripping tower, and the miscella temperature is heated to ~75°C, and the crude oil temperature drops to ~80°C. The oil-oil heat exchanger adopts a tube bundle structure; the heated miscella is sent to the second evaporator and heated with saturated steam, and the outlet miscella concentration reaches more than 95%, and the temperature is ~110°C; finally, it is sent to the stripping tower and stripped with direct steam to obtain crude oil with a solvent content within 50 ppm and a temperature of ~110°C; the crude oil at the outlet of the stripping tower exchanges heat through the oil-oil heat exchanger and is cooled to below 50°C by the oil cooler for storage and transportation. The first evaporator and the second evaporator use the same vacuum with a vacuum degree of 50 - 60 KPa; the stripping tower uses a high vacuum with a vacuum degree of 60 - 70 KPa.

[0004] Chinese Patent with the publication number of CN 206177086U discloses a 4-unit oil / miscella heat exchanger for the evaporation of oil miscella solvent. When the equipment works, the miscella coming out of the first evaporator exchanges heat with the crude oil coming out of the stripping tower. Because the miscella concentration at the first evaporator is high and the flow rate is low, the heat of the crude oil coming out of the stripping tower cannot be fully utilized. The temperature of the crude oil after heat exchange is still 70 - 80°C and still needs to be cooled down to 40 - 50°C for storage.

[0005] The patent with the application number CN 114470841A proposes a heat energy recovery device for the prepreg section. This technical solution uses the steam at the top of the second evaporator or the stripping column to recover the waste heat of the mixed oil entering the second evaporator. This technical solution aims to reduce the steam consumption of the second evaporator and achieve the secondary utilization of heat energy, but both have drawbacks. In Solution 1, the top gas phase of the second evaporator is used to preheat the mixed oil. Since the second evaporator is indirectly heated and the gas phase component is solvent gas, the heat transfer efficiency is not high, the heat transfer area is large, and the input cost is high. In Solution 2, the top gas phase of the stripping column is used to preheat the mixed oil. Most of the gas phase components are water vapor, and the utilization efficiency is high. However, only the heating section is configured and it is only used to raise the temperature of the mixed oil without flashing, so the heat energy of the gas phase of the stripping column is not fully utilized and the concentration of the mixed oil is not increased. Utility Model Content

[0006] The purpose of this part is to outline some aspects of the embodiments of the present utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, as well as in the abstract and the title of the specification of this application, but such simplifications or omissions cannot be used to limit the scope of the present utility model.

[0007] In view of the above and / or problems existing in the prior art, the present utility model is proposed.

[0008] The purpose of the present utility model is to overcome the problems existing in the prior art and provide a leaching mixed oil evaporation system that can improve the heat energy recovery efficiency, reduce steam consumption, and reduce the load of the condensation system.

[0009] To solve the above technical problems, a leaching mixed oil evaporation system of the present utility model includes a mixed oil input pipe. The outlet of the mixed oil input pipe is connected to the tube side inlet of the mixed oil preheater. The tube side outlet of the mixed oil preheater is connected to the oil inlet of the pre-first evaporation flash tank. The oil outlet of the pre-first evaporation flash tank is connected to the shell side inlet of the oil-oil heat exchanger through the pre-first evaporation extraction pump. The shell side outlet of the oil-oil heat exchanger is connected to the oil inlet at the top of the first evaporator. The first evaporator is a falling film evaporator. The bottom oil outlet of the first evaporator is connected to the oil inlet at the top of the pre-second evaporation through the first evaporation extraction pump. The pre-second evaporation is a falling film evaporator. The bottom oil outlet of the pre-second evaporation is connected to the oil inlet of the second evaporator through the pre-second evaporation extraction pump. The second evaporator is a rising film evaporator. The oil outlet of the second evaporator is connected to the oil inlet of the stripping column. The oil outlet of the stripping column is connected to the tube side inlet of the oil-oil heat exchanger through the stripping column extraction pump. The tube side of the oil-oil heat exchanger is connected to the crude oil output pipe.

[0010] As an improvement of the present utility model, the gas phase outlet of the cooking tank is connected to the shell side inlet of the mixed oil preheater through the cooking tank hot gas pipe.

[0011] As a further improvement of the present utility model, the outlet of the stripping hot gas pipe is connected to the inlet of the shell side of the first evaporator.

[0012] As a further improvement of the present utility model, the top gas phase outlet of the stripping column is connected to the inlet of the shell side of the pre-secondary evaporation, the outlet of the shell side of the pre-secondary evaporation is connected to the inlet of the stripping condenser, and the outlet of the stripping condenser is connected to the suction port of the stripping liquid ring vacuum pump.

[0013] As a further improvement of the present utility model, the inlet of the shell side of the second evaporator is connected to the live steam pipe, and the outlet of the shell side of the second evaporator is connected to the condensate collection pipe.

[0014] As a further improvement of the present utility model, the oil-oil heat exchanger is a four-stage series-connected four-unit oil-oil heat exchanger.

[0015] As a further improvement of the present utility model, the exhaust ports of the pre-primary evaporation flash tank, the first evaporator, the pre-secondary evaporation, and the second evaporator are all connected to the inlet of the evaporation condenser through the evaporation vacuum gas main pipe, and the outlet of the evaporation condenser is connected to the suction port of the evaporation liquid ring vacuum pump.

[0016] Compared with the prior art, the present utility model has achieved the following beneficial effects: 1. The hot gas of the cooking tank is used to preheat the miscella, the temperature of the miscella increases, and the load of the condensation system is reduced; a pre-primary evaporation flash tank is configured, and the solvent volatilizes under vacuum, the concentration and temperature of the miscella are increased, and the steam consumption is reduced by 1-2 kg / ton of raw materials;

[0017] 2. An oil-oil heat exchanger is arranged in front of the first evaporator, and the heat exchange area is increased by multi-stage series connection to make full use of the heat of the crude oil. The flow rate of the miscella at the outlet of the oil-oil heat exchanger is 2-2.5 times that of the miscella at the outlet of the first evaporator. The temperature of the miscella entering the first evaporator is increased to above 60 °C, the temperature of the crude oil is reduced to 50 °C and directly sent out of the workshop, the crude oil cooler is cancelled, the load of the condensation system is reduced, and the steam consumption is reduced by 2-4 Kg / ton of raw materials;

[0018] 3. After the pre-primary evaporation flash, the concentration of the miscella is on the high side. If a rising film evaporator is used, the phenomenon of non-rising film is likely to occur. Therefore, the first evaporator adopts a falling film form to ensure stable production; the second evaporator uses live steam as the heat source, has a high evaporation intensity, and adopts a rising film form.

[0019] 4. The gas phase temperature of the stripping column reaches above 100 °C, and the gas phase contains a large amount of water vapor, with high heat transfer efficiency. To make full use of the heat of this gas phase, a pre-secondary evaporation is configured, a falling film evaporator is used, and countercurrent heat exchange is carried out. A separation tank is configured at the bottom. After the miscella enters the separation tank, it flashes under a vacuum of 60-70 KPa, the concentration of the miscella is increased to above 90%wt, the temperature of the miscella is 80 °C, and the steam consumption is reduced by 3-5 Kg / ton of raw materials; and the load of the condensation system is reduced, and the heat exchange area of the stripping condenser is reduced. Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. The drawings are only for reference and explanation, and are not used to limit the present utility model. Among them:

[0021] Figure 1 is a flow chart of the leaching mixed oil evaporation system of the present utility model;

[0022] In the figure: 1. Cooking tank; 2. Mixed oil preheater; 3. Pre-first evaporation flash tank; 4. Oil-oil heat exchanger; 5. First evaporator; 6. Pre-second evaporation; 7. Second evaporator; 8. Stripping tower; 9. Evaporation condenser; 10. Stripping condenser; 11. Evaporation liquid ring vacuum pump; 12. Stripping liquid ring vacuum pump;

[0023] P1. Pre-first evaporation extraction pump; P2. First evaporation extraction pump; P3. Pre-second evaporation extraction pump; P4. Stripping tower extraction pump;

[0024] G1. Mixed oil input pipe; G2. First evaporation inlet oil pipe; G3. Second evaporation mixed oil output pipe; G4. Crude oil return pipe; G5. Crude oil output pipe; G6. Cooking tank hot gas pipe; G7. Pre-first evaporation vacuum gas phase pipe; G8. Desolventizing hot gas pipe; G9. First evaporation vacuum gas phase pipe; G10. Stripping tower vacuum gas phase pipe; G11. Pre-second evaporation shell side gas phase outlet pipe; G12. Pre-second evaporation vacuum gas phase pipe; G13. Second evaporation vacuum gas phase pipe; G14. Evaporation vacuum gas phase main pipe; G15. Evaporation condenser exhaust pipe; G16. Stripping condenser exhaust pipe; G17. Live steam pipe. Detailed Embodiments

[0025] In order to make the technical means, creative features, achieved purposes and effects realized by the present utility model easy to understand, the present utility model will be further described below with reference to specific illustrations. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present utility model belongs. The terms used in the description of the present utility model in this specification are only for the purpose of describing specific embodiments, and are not intended to limit the present utility model.

[0027] Such as Figure 1As shown in the figure, the leaching mixed oil evaporation system of the present utility model includes a cooking tank 1, a mixed oil preheater 2, a first evaporation flash tank 3, an oil-oil heat exchanger 4, a first evaporator 5, a second evaporation 6, a second evaporator 7 and a stripping tower 8. The outlet of the mixed oil input pipe G1 is connected to the tube side inlet of the mixed oil preheater 2, the tube side outlet of the mixed oil preheater 2 is connected to the oil inlet of the first evaporation flash tank 3, the oil outlet of the first evaporation flash tank 3 is connected to the inlet of the first evaporation extraction pump P1, the outlet of the first evaporation extraction pump P1 is connected to the shell side inlet of the oil-oil heat exchanger 4. The oil-oil heat exchanger 4 is a four-unit oil-oil heat exchanger. The shell side outlet of the oil-oil heat exchanger 4 is connected to the oil inlet at the top of the first evaporator 5 through the first evaporation inlet pipe G2. The first evaporator 5 is a falling film evaporator, with countercurrent heat exchange, and a separation tank is configured at the bottom. The bottom oil outlet of the first evaporator 5 is connected to the inlet of the first evaporation extraction pump P2, the outlet of the first evaporation extraction pump P2 is connected to the oil inlet at the top of the second evaporation 6. The second evaporation 6 also uses a falling film evaporator. The bottom oil outlet of the second evaporation 6 is connected to the inlet of the second evaporation extraction pump P3, the outlet of the second evaporation extraction pump P3 is connected to the inlet of the second evaporator 7. The second evaporator 7 uses a rising film evaporator, and a separation tank is provided at the top. The shell side inlet of the second evaporator 7 is connected to the live steam pipe G17, and the shell side outlet of the second evaporator 7 is connected to the condensate collection pipe; the oil outlet of the second evaporator 7 is connected to the oil inlet of the stripping tower 8 through the second evaporation mixed oil output pipe G3. The oil outlet of the stripping tower 8 is connected to the inlet of the stripping tower extraction pump P4, the outlet of the stripping tower extraction pump P4 is connected to the tube side inlet of the oil-oil heat exchanger 4 through the crude oil return pipe G4, and the cooled crude oil is discharged from the workshop through the crude oil output pipe G5.

[0028] The gas phase outlet of the cooking tank 1 is connected to the shell side inlet of the mixed oil preheater 2 through the cooking tank hot gas pipe G6. The top exhaust port of the first evaporation flash tank 3 is connected to the first evaporation vacuum gas phase pipe G7. The exhaust port of the separator at the bottom of the first evaporator 5 is connected to the first evaporation vacuum gas phase pipe G9. The exhaust port of the separator at the bottom of the second evaporation 6 is connected to the second evaporation vacuum gas phase pipe G12. The top exhaust port of the second evaporator 7 is connected to the second evaporation vacuum gas phase pipe G13. The outlets of the first evaporation vacuum gas phase pipe G7, the first evaporation vacuum gas phase pipe G9, the second evaporation vacuum gas phase pipe G12, and the second evaporation vacuum gas phase pipe G13 are all connected to the evaporation vacuum gas phase main pipe G14. The outlet of the evaporation vacuum gas phase main pipe G14 is connected to the inlet of the evaporation condenser 9. The outlet of the evaporation condenser 9 is connected to the suction port of the evaporation liquid ring vacuum pump 11 through the evaporation condenser exhaust pipe G15. The exhaust port of the evaporation liquid ring vacuum pump 11 is connected to the tail gas condensation unit.

[0029] The outlet of the stripping hot gas pipe G8 is connected to the inlet of the shell side of the first evaporator 5. The top gas phase outlet of the stripping column 8 is connected to the inlet of the shell side of the pre-secondary evaporator 6 through the stripping column vacuum gas phase pipe G10. The outlet of the shell side of the pre-secondary evaporator 6 is connected to the inlet of the stripping condenser 10 through the pre-secondary evaporator shell side gas phase outlet pipe G11. The outlet of the stripping condenser 10 is connected to the suction port of the stripping liquid ring vacuum pump 12 through the stripping condenser exhaust pipe G16. The exhaust port of the stripping liquid ring vacuum pump 12 is connected to the tail gas condensation unit.

[0030] The mixed oil input pipe G1 sends the mixed oil with a temperature of 55 °C and a concentration of 25 - 30%wt into the tube side of the mixed oil preheater 2 for heating. After the temperature of the mixed oil rises by 1 - 2 °C, it is sent into the pre-primary evaporation flash tank 3 for vacuum flashing. The vacuum degree is controlled at 55 - 60 KPa, the temperature of the mixed oil is 46 - 50 °C, and the concentration of the mixed oil rises to 34 - 38%wt.

[0031] The mixed oil coming out of the pre-primary evaporation flash tank 3 is sent into the inlet of the shell side of the oil-oil heat exchanger 4 by the pre-primary evaporation extraction pump P1, and exchanges heat with the crude oil sent into the tube side of the oil-oil heat exchanger 4 by the stripping column extraction pump P4. The temperature of the mixed oil rises to above 60 °C.

[0032] After the mixed oil is heat-exchanged in the oil-oil heat exchanger 4 and discharged from the outlet of the shell side of the oil-oil heat exchanger 4, it enters the top of the first evaporator 5 through the first evaporation inlet pipe G2, is evenly distributed to each tube through the liquid distribution tray, the mixed oil descends along the tube wall to form a liquid film, enters the bottom separator, and flashes under a vacuum degree of 55 - 60 KPa. The concentration of the mixed oil at the bottom outlet of the first evaporator 5 reaches above 80%wt, and the temperature is about 60 °C.

[0033] The mixed oil discharged from the bottom of the first evaporator 5 is sent into the top of the pre-secondary evaporator 6 by the first evaporation extraction pump P2, is evenly distributed to each tube through the liquid distribution tray, the mixed oil descends along the tube wall to form a liquid film, enters the bottom separator, and flashes under a vacuum degree controlled at 55 - 60 KPa, and continues to be heated for solvent removal. The concentration of the mixed oil at the bottom outlet of the pre-secondary evaporator 6 reaches above 90%wt, and the temperature is about 80 °C.

[0034] The mixed oil discharged from the bottom of the pre-secondary evaporator 6 is sent into the bottom inlet of the second evaporator 7 by the pre-secondary evaporation extraction pump P3, and is heated by fresh saturated steam. The vacuum degree is controlled at 55 - 60 KPa. The concentration of the mixed oil at the outlet of the second evaporator 7 reaches 95 - 98%wt, and the temperature of the mixed oil reaches 105 - 110 °C.

[0035] The second evaporator 7 uses live steam as the heat source to increase the evaporation intensity. The mixed oil coming out of the second evaporator 7 flows into the stripping column 8 by gravity. The stripping column 8 uses direct steam stripping to remove trace solvents. The vacuum degree is controlled at 60 - 70 KPa, the temperature of the crude oil is 105 - 110 °C, and the residual solvent in the crude oil is <50 ppm.

[0036] The crude oil discharged from the stripping column 8 is sent to the tube side of the oil-oil heat exchanger 4 by the stripping column extraction pump P4, and exchanges heat with the mixed oil sent to the shell side of the oil-oil heat exchanger 4 by the pre-first evaporation extraction pump P1. The temperature of the crude oil drops to about 50°C and enters the tank farm for storage through the crude oil output pipe G5.

[0037] The secondary steam discharged from the cooking tank 1 enters the shell side of the mixed oil preheater 2 through the cooking tank hot gas pipe G6 to heat the mixed oil sent by the mixed oil input pipe G1.

[0038] The secondary steam from the vapor phase of the desolventizer is sent to the shell side of the first evaporator 5 through the desolventizing hot gas pipe G8 as a heat source to heat the mixed oil in the tube side.

[0039] The solvent gases discharged from the pre-first evaporation vacuum gas pipe G7, the first evaporation vacuum gas pipe G9, the pre-second evaporation vacuum gas pipe G12, and the second evaporation vacuum gas pipe G13 are collected and enter the main evaporation vacuum gas pipe G14, and then enter the evaporation condenser 9 for condensation. The non-condensable gas discharged from the evaporation condenser 9 enters the evaporation liquid ring vacuum pump 11 through the evaporation condenser exhaust pipe G15. The evaporation liquid ring vacuum pump 11 provides an evaporation vacuum degree of 55-60 KPa.

[0040] The secondary steam discharged from the top of the stripping column 8 enters the shell side of the pre-second evaporation 6 as a heat source to heat the mixed oil in the tube side. The secondary steam after heat exchange in the pre-second evaporation 6 is discharged from the top outlet of the shell side and sent to the stripping condenser 10 through the pre-second evaporation shell side gas phase outlet pipe G11 for condensation. The non-condensable gas discharged from the stripping condenser 10 enters the stripping liquid ring vacuum pump 12 through the stripping condenser exhaust pipe G16. The stripping liquid ring vacuum pump 12 provides a stripping vacuum degree of 60-70 KPa.

[0041] The above is only the preferred and feasible embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention. It is not intended to limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. Except for the above embodiments, without departing from the spirit and scope of the present invention, the present invention may have other implementation manners. The present invention 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 present invention. The scope of protection required by the present invention is defined by the appended claims and their equivalents. The technical features not described in the present invention can be realized by or adopted from the prior art, and will not be elaborated here.

Claims

1. An evaporation system for leaching miscella, comprising a miscella input pipe, characterized in that, The outlet of the miscella inlet pipe is connected to the inlet of the tube side of the miscella preheater. The outlet of the tube side of the miscella preheater is connected to the oil inlet of the pre-first evaporation flash tank. The oil outlet of the pre-first evaporation flash tank is connected to the inlet of the shell side of the oil-oil heat exchanger through the pre-first evaporation extraction pump. The outlet of the shell side of the oil-oil heat exchanger is connected to the oil inlet at the top of the first evaporator. The first evaporator is a falling film evaporator. The bottom oil outlet of the first evaporator is connected to the oil inlet at the top of the pre-second evaporation through the first evaporation extraction pump. The pre-second evaporation is a falling film evaporator. The bottom oil outlet of the pre-second evaporation is connected to the oil inlet of the second evaporator through the pre-second evaporation extraction pump. The second evaporator is a rising film evaporator. The oil outlet of the second evaporator is connected to the oil inlet of the stripping column. The oil outlet of the stripping column is connected to the inlet of the tube side of the oil-oil heat exchanger through the stripping column extraction pump. The tube side of the oil-oil heat exchanger is connected to the crude oil output pipe.

2. The leaching miscella evaporation system according to claim 1, wherein: The gas phase outlet of the cooking tank is connected to the inlet of the shell side of the miscella preheater through the cooking tank hot gas pipe.

3. The leaching miscella evaporation system according to claim 1, wherein: The outlet of the desolventizing hot gas pipe is connected to the gas inlet of the shell side of the first evaporator.

4. The leaching mixed oil evaporation system according to claim 1, characterized in that: The top gas phase outlet of the stripping column is connected to the gas inlet of the shell side of the pre-second evaporation. The gas outlet of the shell side of the pre-second evaporation is connected to the gas inlet of the stripping condenser. The gas outlet of the stripping condenser is connected to the suction port of the stripping liquid ring vacuum pump.

5. The leaching miscella evaporation system according to claim 1, characterized in that: The inlet of the shell side of the second evaporator is connected to the live steam pipe. The outlet of the shell side of the second evaporator is connected to the condensate collection pipe.

6. The leaching mixed oil evaporation system according to claim 1, characterized in that: The oil-oil heat exchanger is a four-stage series-connected four-unit oil-oil heat exchanger.

7. The leaching miscella evaporation system according to any one of claims 1 to 6, characterized in that: The exhaust ports of the pre-first evaporation flash tank, the first evaporator, the pre-second evaporation, and the second evaporator are all connected to the gas inlet of the evaporation condenser through the evaporation vacuum gas main pipe. The gas outlet of the evaporation condenser is connected to the suction port of the evaporation liquid ring vacuum pump.

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