High-vacuum mixed oil evaporation desolventizing system

Abstract

The utility model discloses a kind of high-vacuum mixed oil evaporation desolventizing systems, the outlet of extraction mixed oil pipe is connected to first evaporator, one evaporated condensed oil outlet is connected with second evaporator through the shell side of oil oil heat exchanger, two evaporated condensed oil outlet is connected with stripping column, stripping column outlet is connected with crude oil outlet pipe through the tube side of oil oil heat exchanger;The outlet of evaporation and removal machine secondary steam pipe is connected with the shell side inlet of first evaporator, one evaporated shell side outlet is connected with secondary steam outlet pipe through the shell side of economizer;The outlet of fresh solvent pump is connected with the tube side of economizer, then is connected with fresh solvent outlet pipe through the tube side of stripping pre-condenser;The top outlet of first, second evaporator is connected with the shell side of evaporative condenser, the shell side of No. 1 refrigeration condenser and the suction port of No. 1 steam jet pump in turn, the outlet of No. 1 steam jet pump is connected with the bypass inlet of evaporation and removal machine secondary steam pipe. The system can evaporate mixed oil under high-vacuum condition, reduce steam consumption and solvent consumption.

Description

Technical Field

[0001] This utility model relates to a solvent removal system for oils and fats, and more particularly to a high-vacuum mixed oil evaporation and solvent removal system, belonging to the technical field of oil leaching processing equipment. Background Technology

[0002] Negative pressure evaporation technology is widely used in the oil processing industry and is one of the key technologies for improving oil yield and quality. Using negative pressure evaporation lowers the boiling point of mixed oils, allowing for the effective utilization of secondary steam in the descaling machine and directly reducing the amount of fresh steam used. Furthermore, the lower boiling point also reduces the operating temperature in the workshop, indirectly reducing the consumption of solvents, circulating water, and mineral oil. Therefore, by optimizing the negative pressure evaporation process, low consumption in the leaching process can be effectively achieved, improving the economic efficiency of the plant.

[0003] Currently, traditional negative pressure evaporation processes generally use ambient temperature water cooling, and the condenser efficiency is limited by the cooling water temperature. For example, when the cooling water temperature is 30°C, the solvent condensate temperature is also limited to 30°C. At this temperature, the saturated vapor pressure of n-hexane is approximately 25 kPa, so the system vacuum can only reach a maximum of about -76 kPa. However, in hot weather or when the ambient wet-bulb temperature is high, the cooling water temperature may not meet the process design requirements. This leads to reduced condenser efficiency, as a significant portion of the solvent vapor remains uncondensed and directly enters the steam jet pump, resulting in a large pumping volume and heavy load. Simultaneously, the amount of condensed solvent decreases, leading to low solvent recovery and increased solvent consumption. Furthermore, the solvent condensate temperature rises, causing more free gas to be generated in the distribution tank and enter the tail gas absorption system, increasing the amount of adsorption medium (such as mineral oil) needed to recover residual solvent. In addition, the increase in condensate temperature also means that the vacuum that the evaporation system can achieve will decrease, which will cause the boiling point of the mixed oil to rise. The secondary steam of the desiccant will not be effectively utilized, and the amount of fresh steam used will also increase. At the same time, the incomplete use of secondary steam will require more circulating water to cool and recover the solvent, which will increase the water consumption in the workshop.

[0004] Chinese patent application CN 1301800A discloses a "mixed oil negative pressure evaporation process." The technical solution involves the mixed oil from the leachate first entering a first evaporator for concentration, with the heat source being secondary steam from the descaling machine (temperature 85°C). After the oil and secondary steam enter the first evaporator, a steam jet pump is activated. Under these conditions, the concentration of the mixed oil exiting the first evaporator is 70%. The mixed oil then sequentially passes through a mixed oil heater, a second evaporator, and a stripping tower for further concentration, with the stripping tower also being evacuated by the aforementioned steam jet pump. This scheme uses an evaporation system with a pressure of 47 kPa, which is relatively high. Furthermore, the temperature of the fresh solvent after water separation reaches 60°C, leading to an increase in the amount of free gas in the water separator and a greater load on the exhaust gas system. Utility Model Content

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0006] In view of the problems existing in the above and / or prior art, this utility model is proposed.

[0007] The purpose of this invention is to overcome the problems existing in the prior art and provide a high-vacuum mixed oil evaporation and desolventizing system that can perform evaporation of extracted mixed oil under higher vacuum conditions, thereby reducing steam consumption and solvent consumption, and improving exhaust gas emission indicators and system operation stability.

[0008] To solve the above technical problems, this utility model provides a high-vacuum mixed oil evaporation and desolventizing system, including an leaching mixed oil pipe. The outlet of the leaching mixed oil pipe is connected to the tube-side inlet of a first evaporator. The concentrated oil outlet of the first evaporator is connected to the shell-side inlet of an oil-to-oil heat exchanger. The shell-side outlet of the oil-to-oil heat exchanger is connected to the tube-side inlet of a second evaporator. The concentrated oil outlet of the second evaporator is connected to the spray port of a stripping tower via a secondary steam extraction pump. The bottom outlet of the stripping tower is connected to the tube-side inlet of the oil-to-oil heat exchanger via a stripping pump. The tube-side outlet of the oil-to-oil heat exchanger is connected to the crude oil outlet pipe. The outlet of the secondary steam pipe of the desolventizing machine is connected to the... The shell-side inlet of the first evaporator is connected to the shell-side outlet of the first evaporator, which is connected to the secondary steam outlet pipe via the shell-side of the economizer; the outlet of the fresh solvent pump is connected to the tube-side inlet of the economizer, which is connected to the fresh solvent outlet pipe via the tube-side of the stripping pre-condenser; the top vapor phase outlets of the first and second evaporators are connected to the shell-side inlet of the evaporative condenser, the shell-side outlet of the evaporative condenser is connected to the shell-side inlet of the No. 1 refrigeration condenser, the shell-side outlet of the No. 1 refrigeration condenser is connected to the suction port of the No. 1 steam jet pump, and the outlet of the No. 1 steam jet pump is connected to the bypass inlet of the secondary steam pipe of the desiccant.

[0009] As an improvement of this utility model, the top gas phase outlet of the stripping tower is connected to the shell-side inlet of the stripping pre-condenser, the shell-side outlet of the stripping pre-condenser is connected to the shell-side inlet of the stripping condenser, the shell-side outlet of the stripping condenser is connected to the shell-side inlet of the No. 2 refrigeration condenser, the shell-side outlet of the No. 2 refrigeration condenser is connected to the suction port of the No. 2 steam jet pump, and the outlet of the No. 2 steam jet pump is connected to the bypass inlet of the secondary steam pipe of the desiccant.

[0010] As a further improvement of this utility model, the outlet of the refrigerant water storage tank is connected to the inlet of the refrigerant water pump, the outlet of the refrigerant water pump is connected to the refrigerant water inlet of the refrigeration unit, the refrigerant water outlet of the refrigeration unit is connected to the tube-side inlet of the No. 1 and No. 2 refrigeration condensers, and the tube-side outlets of the No. 1 and No. 2 refrigeration condensers are all connected to the return outlet of the refrigerant water storage tank through a refrigerant water return pipe.

[0011] As a further improvement of this utility model, the shell-side condensate outlets of the first evaporator, evaporative condenser, stripping pre-condenser, stripping condenser and No. 1 refrigeration condenser are respectively connected to the condensate collection port of the water distribution tank. The inner cavity of the water distribution tank is provided with an overflow baffle, and the solvent outlet of the water distribution tank is connected to the inlet of the fresh solvent pump.

[0012] Compared to the prior art, the advantages or beneficial effects of the embodiments of this application include at least the following:

[0013] 1. Add a stripping pre-condenser before the stripping condenser and an energy-saving device after the first evaporator; the fresh solvent in the water distribution tank passes through the energy-saving device and the stripping pre-condenser in sequence, effectively utilizing the secondary steam of the stripping tower and the descaling machine, reducing the steam consumption for heating the fresh solvent, and reducing the amount of circulating water used in the workshop.

[0014] 2. Add a refrigeration condenser after the evaporator and stripping condenser respectively; this allows the solvent vapor that is not condensed in the condenser to enter the refrigeration condenser for re-condensation, reducing non-condensable gases, lowering the workload of the steam jet pump, increasing the system negative pressure, lowering the boiling point of the mixed oil, and reducing production steam consumption. At the same time, the amount of condensed solvent increases, the solvent recovery rate improves, the load on the exhaust gas system decreases, the consumption of solvent and mineral oil decreases, and the odor of the exhaust gas is reduced, ultimately achieving energy conservation and emission reduction in the factory.

[0015] 3. One ton of oil can save 5-10 kg of steam consumption; for a factory that processes 6,000 tons per day, with a steam price of 250 yuan / ton and 300 processing days per year, the annual processing cost can be saved by at least 6,000 * 5 / 1,000 * 250 * 300 = 2.25 million yuan. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit this utility model. Wherein:

[0017] Figure 1 This is a flowchart of the high-vacuum mixed oil evaporation and desolvation system of this utility model;

[0018] In the diagram: P1. Fresh solvent pump; P2. Secondary distillation extraction pump; P3. Stripping pump; P4. No. 1 steam jet pump; P5. No. 2 steam jet pump; P6. Refrigerant water pump;

[0019] E1. First evaporator; E2. Second evaporator; E3. Stripping tower; E4. Water distribution tank; E5. Refrigeration unit; E6. Eco-friendly unit;

[0020] H1. Oil-to-oil heat exchanger; H2. Evaporative condenser; H3. Stripping pre-condenser; H4. Stripping condenser; H5. No. 1 refrigeration condenser; H6. No. 2 refrigeration condenser;

[0021] T1. Refrigerant water storage tank;

[0022] G1. Leaching mixed oil pipe; G2. Crude oil outlet pipe; G3. Secondary steam pipe of the descaling machine; G4. Secondary steam outlet pipe; G5. Circulating water supply pipe; G6. Circulating water return pipe; G7. Fresh solvent outlet pipe. Detailed Implementation

[0023] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0024] To make the technical means, creative features, achieved objectives and effects of this utility model easier 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 this utility model, and not all embodiments.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0026] like Figure 1As shown, taking a 6000 TPD soybean pre-soaking plant as an example, the high-vacuum mixed oil evaporation and desolventizing system of this invention is configured with three stages of evaporation: a first evaporator E1, a second evaporator E2, and a stripping tower E3. The outlet of the leaching mixed oil pipe G1 is connected to the tube-side inlet of the first evaporator E1; the concentrated oil outlet of the first evaporator E1 is connected to the shell-side inlet of the oil-to-oil heat exchanger H1; the shell-side outlet of the oil-to-oil heat exchanger H1 is connected to the tube-side inlet of the second evaporator E2; the concentrated oil outlet of the second evaporator E2 is connected to the inlet of the second evaporator extraction pump P2; the outlet of the second evaporator extraction pump P2 is connected to the spray port of the stripping tower E3; the bottom outlet of the stripping tower E3 is connected to the inlet of the stripping pump P3; the outlet of the stripping pump P3 is connected to the tube-side inlet of the oil-to-oil heat exchanger H1; and the tube-side outlet of the oil-to-oil heat exchanger H1 is connected to the crude oil outlet pipe G2.

[0027] The outlet of the secondary steam pipe G3 of the desiccant is connected to the shell-side inlet of the first evaporator E1, the shell-side outlet of the first evaporator E1 is connected to the shell-side inlet of the economizer E6, and the shell-side outlet of the economizer E6 is connected to the secondary steam outlet pipe G4.

[0028] The solvent outlet of the water distribution tank E4 is connected to the inlet of the fresh solvent pump P1. The outlet of the fresh solvent pump P1 is connected to the tube-side inlet of the energy saver E6. The tube-side outlet of the energy saver E6 is connected to the tube-side inlet of the stripping pre-condenser H3. The tube-side outlet of the stripping pre-condenser H3 is connected to the fresh solvent outlet pipe G7.

[0029] The top vapor outlets of the first evaporator E1 and the second evaporator E2 are connected to the shell-side inlet of the evaporative condenser H2. The shell-side outlet of the evaporative condenser H2 is connected to the shell-side inlet of the first refrigeration condenser H5. The shell-side outlet of the first refrigeration condenser H5 is connected to the suction port of the first steam jet pump P4. The outlet of the first steam jet pump P4 is connected to the bypass inlet of the secondary steam pipe G3 of the desiccant.

[0030] The top vapor outlet of stripping tower E3 is connected to the shell-side inlet of stripping pre-condenser H3. The shell-side outlet of stripping pre-condenser H3 is connected to the shell-side inlet of stripping condenser H4. The shell-side outlet of stripping condenser H4 is connected to the shell-side inlet of No. 2 refrigeration condenser H6. The shell-side outlet of No. 2 refrigeration condenser H6 is connected to the suction port of No. 2 steam jet pump P5. The outlet of No. 2 steam jet pump P5 is connected to the bypass inlet of secondary steam pipe G3 of the desiccant.

[0031] The outlet of the refrigerant water storage tank T1 is connected to the inlet of the refrigerant water pump P6. The outlet of the refrigerant water pump P6 is connected to the refrigerant water inlet of the refrigeration unit E5. The refrigerant water outlet of the refrigeration unit E5 is connected to the tube-side inlet of the first refrigeration condenser H5 and the second refrigeration condenser H6. The tube-side outlets of the first refrigeration condenser H5 and the second refrigeration condenser H6 are both connected to the return water outlet of the refrigerant water storage tank T1 through the refrigerant water return pipe.

[0032] The shell-side condensate outlets of the first evaporator E1, evaporative condenser H2, stripping pre-condenser H3, stripping condenser H4, and first refrigeration condenser H5 are respectively connected to the condensate collection port of the water distribution tank E4. The water distribution tank E4 is equipped with an overflow baffle. The condensate enters the right side of the water distribution tank E4, while the less dense solvent overflows from the top of the overflow baffle into the left side of the water distribution tank E4 and is drawn out by the fresh solvent pump P1.

[0033] The mixed oil from the extractor enters the tube side of the first evaporator E1 through the leaching mixed oil pipe G1 for heating. The secondary steam pipe G3 of the desiccant sends the secondary steam generated by the desiccant to the shell side of the first evaporator E1 as a heat source. The mixed oil is concentrated to 75% oil concentration in the first evaporator E1 and the oil outlet temperature is about 50°C.

[0034] During this process, the secondary steam from the desiccant that has not been fully utilized after passing through the first evaporator E1 is discharged from the shell side of the first evaporator E1 and enters the shell side of the economizer E6 to heat the fresh solvent, raising the temperature of the fresh solvent by about 5°C.

[0035] The mixed oil discharged from the first evaporator E1 enters the shell side of the oil-to-oil heat exchanger H1 to exchange heat with the crude oil from the stripping tower E3. After heat exchange, the temperature of the mixed oil reaches 70°C, and it then enters the second evaporator E2 for secondary evaporation. The second evaporator E2 typically uses fresh steam as a heat source to further concentrate the mixed oil to 95-99% oil concentration at a temperature of 95-105°C.

[0036] The mixed oil discharged from the second evaporator E2 is pumped into the stripping tower E3 via the secondary evaporation extraction pump P2 for direct vapor desolventizing, ultimately reducing the residual solvent in the crude oil to below 50 ppm. The crude oil discharged from the stripping tower E3 is then sent to the tube side of the oil-to-oil heat exchanger H1 via the stripping pump P3, and finally enters the refining workshop through the crude oil outlet pipe G2. During the evaporation and stripping processes described above, the solvent vapors generated at different stages are efficiently condensed and recovered.

[0037] The solvent vapors discharged from the tops of the first evaporator E1 and the second evaporator E2 merge and enter the evaporative condenser H2 for condensation, where the temperature drops to 52-58℃. The incompletely condensed portion, including a small amount of solvent vapor and non-condensable gases, enters the shell side of the first refrigeration condenser H5 for further condensation. After condensation in the first refrigeration condenser H5, the remaining non-condensable gases drop to approximately 15℃. After two stages of condensation, most of the solvent vapors generated by the first evaporator E1 and the second evaporator E2 have been recovered as condensate. The negative pressure of the first evaporator E1 and the second evaporator E2 is provided by the first steam jet pump P4, and the pressure is maintained at an absolute pressure of approximately 20-30 kPa.

[0038] The mixed steam from the top of stripping tower E3 first enters the shell side of stripping pre-condenser H3 to exchange heat with the fresh solvent supplied from the tube side of economizer E6, recovering heat energy. At this time, the temperature of the fresh solvent rises to approximately 40°C and is discharged through the fresh solvent outlet pipe G7. Simultaneously, the temperature of the mixed steam exiting from the shell side of stripping pre-condenser H3 decreases from 85°C to 30-40°C, condensing some solvent and water.

[0039] The uncondensed gas enters the shell side of the stripping condenser H4 for further condensation, and the temperature is further reduced. After two condensations, a small amount of mixed gas remains, which enters the shell side of the second refrigeration condenser H6 for final condensation. The negative pressure of the stripping tower is provided by the second steam jet pump P5, and the pressure is maintained at an absolute pressure of 10-20 kPa.

[0040] The condensate from all the above condensers eventually flows into the water distribution tank E4. The separated solvent is pumped out by the fresh solvent pump P1 and sent to the tube side of the economizer E6 for primary preheating. Then it enters the tube side of the stripping pre-condenser H3 for secondary preheating, and then is sent back to the leaching tank for recycling. The chilled water for the tube side of the first refrigeration condenser H5 and the second refrigeration condenser H6 is supplied by the chiller E5. After the chilled water is heated by heat exchange, it enters the chilled water storage tank T1, and is then pumped by the chilled water pump P6 into the chilled water inlet of the chiller for recirculation and refrigeration. The outlet of the circulating water supply pipe G5 is connected to the cooling water inlet of the chiller E5, and the cooling water outlet of the chiller E5 is connected to the circulating water return pipe G6.

[0041] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A high-vacuum mixed oil evaporation and desolventizing system, comprising an leaching mixed oil pipe (G1), characterized in that: The outlet of the leaching mixed oil pipe (G1) is connected to the tube-side inlet of the first evaporator (E1). The concentrated oil outlet of the first evaporator (E1) is connected to the shell-side inlet of the oil-oil heat exchanger (H1). The shell-side outlet of the oil-oil heat exchanger (H1) is connected to the tube-side inlet of the second evaporator (E2). The concentrated oil outlet of the second evaporator (E2) is connected to the spray port of the stripping tower (E3) through the secondary evaporation extraction pump (P2). The bottom outlet of the stripping tower (E3) is connected to the tube-side inlet of the oil-oil heat exchanger (H1) through the stripping pump (P3). The tube-side outlet of the oil-oil heat exchanger (H1) is connected to the crude oil outlet pipe (G2). The outlet of the secondary steam pipe (G3) of the evaporator is connected to the shell-side inlet of the first evaporator (E1), and the shell-side outlet of the first evaporator (E1) is connected to the secondary steam outlet pipe (G4) via the shell side of the economizer (E6). The outlet of the fresh solvent pump (P1) is connected to the inlet of the economizer (E6), and the outlet of the economizer (E6) is connected to the outlet pipe (G7) of the fresh solvent via the tube side of the stripping pre-condenser (H3). The top vapor outlets of the first evaporator (E1) and the second evaporator (E2) are connected to the shell-side inlet of the evaporative condenser (H2). The shell-side outlet of the evaporative condenser (H2) is connected to the shell-side inlet of the first refrigeration condenser (H5). The shell-side outlet of the first refrigeration condenser (H5) is connected to the suction port of the first steam jet pump (P4). The outlet of the first steam jet pump (P4) is connected to the bypass inlet of the secondary steam pipe (G3) of the desiccant.

2. The high-vacuum mixed oil evaporation and desolventizing system according to claim 1, characterized in that: The top vapor outlet of the stripping tower (E3) is connected to the shell-side inlet of the stripping pre-condenser (H3), the shell-side outlet of the stripping pre-condenser (H3) is connected to the shell-side inlet of the stripping condenser (H4), the shell-side outlet of the stripping condenser (H4) is connected to the shell-side inlet of the second refrigeration condenser (H6), the shell-side outlet of the second refrigeration condenser (H6) is connected to the suction port of the second steam jet pump (P5), and the outlet of the second steam jet pump (P5) is connected to the bypass inlet of the secondary steam pipe (G3) of the desiccant.

3. The high-vacuum mixed oil evaporation and desolventizing system according to claim 2, characterized in that: The outlet of the refrigerant water storage tank (T1) is connected to the inlet of the refrigerant water pump (P6), the outlet of the refrigerant water pump (P6) is connected to the refrigerant water inlet of the refrigeration unit (E5), the refrigerant water outlet of the refrigeration unit (E5) is connected to the tube-side inlet of the first refrigeration condenser (H5) and the second refrigeration condenser (H6), and the tube-side outlets of the first refrigeration condenser (H5) and the second refrigeration condenser (H6) are both connected to the return port of the refrigerant water storage tank (T1) through a refrigerant water return pipe.

4. The high-vacuum mixed oil evaporation and desolventizing system according to claim 2, characterized in that: The shell-side condensate outlets of the first evaporator (E1), evaporative condenser (H2), stripping pre-condenser (H3), stripping condenser (H4), and first refrigeration condenser (H5) are respectively connected to the condensate collection port of the water distribution tank (E4). The water distribution tank (E4) is equipped with an overflow baffle. The solvent outlet of the water distribution tank (E4) is connected to the inlet of the fresh solvent pump (P1).

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