Complete equipment for subcritical low-temperature extraction and flexible processing

Abstract

The utility model relates to subcritical low-temperature extraction flexible processing complete equipment which comprises an extraction tank, an evaporation tank, a first solvent tank, a second solvent tank, an exhaust pipeline, a high-pressure recovery system, a normal-pressure recovery system, a heating water path and a condensate water path, the first solvent tank and the second solvent tank are respectively communicated with the extraction tank, and the extraction tank is communicated with the evaporation tank; the high-pressure recovery system comprises a compressor buffer tank, an air compressor and a first condenser which are sequentially communicated through pipelines; the extraction tank and the evaporation tank are sequentially communicated through a compressor buffer tank, an air compressor and a first condenser; the first condenser is communicated into a first solvent tank; the normal-pressure recovery system comprises a water ring vacuum pump and a first vacuum buffer tank which are communicated through a pipeline; the extraction tank and the evaporation tank are both communicated with a water ring vacuum pump and a first vacuum buffer tank; the first vacuum buffer tank is communicated with the second solvent tank; the residual solvent in the extraction tank and the evaporation tank is effectively recovered, so that the waste of the solvent can be avoided, and the pollution to the atmosphere and water can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical engineering, and particularly relates to a complete set of flexible processing equipment for subcritical low-temperature extraction. Background Art

[0002] At present, n-hexane is mainly used for extracting edible vegetable oils in China, and a few manufacturers also use supercritical extraction, but its investment and production costs are relatively high, making it difficult to form large-scale production. In foreign countries, industrial n-hexane is generally used for oil extraction, and some also use pentane, octane, etc. The technology of extracting oil with subcritical solvents (R134a, Solvent No. 4, Solvent No. 6 and their mixed solvents) is a brand-new oil production technology and is a food processing aid stipulated in China. Compared with the technology of extracting oil with n-hexane widely used at present, it has obvious economic and social benefits. Its outstanding advantages are "extraction at normal temperature and desolventization at low temperature", which can extract oil without destroying the active substances and plant proteins in oilseeds, creating conditions for the extraction of precious oilseeds and the development and utilization of plant proteins. Secondly, the steam consumption is small, thus reducing costs and reducing the emission of "three wastes".

[0003] However, after extraction, there are still residual subcritical solvents in the meal in the extraction tank and the mixed liquid in the evaporation tank, and there are also residual vaporized subcritical solvents in the extraction tank and the evaporation tank. If the un-recovered subcritical solvents are discharged together with the meal and waste liquid, it will not only cause waste of solvents, but also cause environmental pollution. Especially fluorides such as R134a have a potential destructive effect on the ozone layer. However, the liquefaction conditions of R134a solvent, Solvent No. 4 and Solvent No. 6 are different, and the recovery system needs to simultaneously handle the different characteristics of multiple solvents. It is technically challenging to separate and recover the residual subcritical solvents in the meal in the extraction tank and the mixed liquid in the evaporation tank.

[0004] Based on this, it is necessary to study a complete set of flexible processing equipment for subcritical low-temperature extraction. Content of the Utility Model

[0005] In view of this, the purpose of the utility model is to provide a complete set of flexible processing equipment for subcritical low-temperature extraction, which can effectively solve the problem that it is difficult to recycle the residual extraction solvent after subcritical low-temperature extraction.

[0006] To achieve the above purpose, the technical solution adopted by the utility model is:

[0007] A complete set of flexible processing equipment for subcritical low-temperature extraction, comprising an extraction tank, an evaporation tank, a first solvent tank, a second solvent tank, an exhaust pipeline, a high-pressure recovery system, an atmospheric-pressure recovery system, a heating water circuit and a condensation water circuit;

[0008] The discharge ports of the first solvent tank and the second solvent tank are respectively connected to the extraction tank through pipelines via valves, and the liquid discharge port of the extraction tank is connected to the liquid inlet of the evaporation tank through a pipeline;

[0009] The high-pressure recovery system includes a compressor buffer tank, an air compressor, and a first condenser that are connected in sequence through pipelines;

[0010] The exhaust ports of the extraction tank and the evaporation tank are both connected in sequence through pipelines via valves to the compressor buffer tank, the air compressor, and the first condenser; the output port of the first condenser is connected to the first solvent tank through a pipeline;

[0011] The atmospheric pressure recovery system includes a water ring vacuum pump and a first vacuum buffer tank that are connected through a pipeline;

[0012] The exhaust ports of the extraction tank and the evaporation tank are both connected in sequence through pipelines via valves to the water ring vacuum pump and the first vacuum buffer tank; the output port of the first vacuum buffer tank is connected to the second solvent tank through a pipeline;

[0013] The water ring vacuum pump, the first solvent tank, and the second solvent tank are all connected to the exhaust pipeline through valves, and the output port of the exhaust pipeline is connected to the outside;

[0014] The heating water circuit exchanges heat with the extraction tank and the evaporation tank respectively;

[0015] The condensation water circuit exchanges heat with the first vacuum buffer tank and the first condenser respectively.

[0016] Further, the first vacuum buffer tank is connected to the compressor buffer tank through a pipeline via a valve.

[0017] Further, a second vacuum buffer tank is provided on the connecting pipeline between the output port of the water ring vacuum pump and the exhaust pipeline, and a valve is provided on the connecting pipeline between the water ring vacuum pump and the second vacuum buffer tank.

[0018] Further, the exhaust port of the first solvent tank is connected to the exhaust pipeline through a pipeline, the exhaust port of the second solvent tank is connected to the exhaust pipeline through the second condenser in sequence, and the condensation water circuit exchanges heat with the second condenser.

[0019] Further, a flame arrester is provided at the output port of the exhaust pipeline.

[0020] Further, two groups of first solvent tanks are provided, the discharge ports of the two groups of first solvent tanks are respectively connected to the extraction tank through pipelines via valves, and the output port of the first condenser is respectively connected to the two groups of first solvent tanks through valves.

[0021] Furthermore, first heating jackets are provided on the outer surfaces of the first solvent tank and the second solvent tank, and the heating water circuit passes through the corresponding first heating jackets to exchange heat with the first solvent tank and the second solvent tank respectively.

[0022] Furthermore, second heating jackets are provided on the outer surfaces of the extraction tank and the evaporation tank. Further, a condensation coil is provided in the first vacuum buffer tank, and the condensation water circuit passes through the condensation coil to exchange heat with the first vacuum buffer tank.

[0023] The beneficial effects of the above technical solution are as follows:

[0024] In the present utility model, the residual liquid in the extraction tank and the evaporation tank is heated to vaporize it. Also, according to the differences in the pressure conditions when the R134a solvent, the No. 4 solvent, and the No. 6 solvent change from the gaseous state to the liquid state, a high-pressure recovery system and an atmospheric-pressure recovery system are designed to condense the R134a solvent and the No. 4 solvent that require high-pressure conditions and the No. 6 solvent that requires atmospheric-pressure conditions respectively. By adjusting the valves to switch the pipelines, different extraction liquids are input into the extraction tank and the evaporation tank one by one, and the residual extraction liquid therein is recovered. This can not only avoid waste of solvents but also prevent solvents from being discharged into the environment, reducing pollution to the atmosphere and water bodies. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the present utility model.

[0026] Reference numerals: 1 is the extraction tank, 2 is the evaporation tank, 3 is the first solvent tank, 4 is the second solvent tank, 5 is the exhaust pipeline, 6 is the heating water circuit, 7 is the condensation water circuit, 8 is the compressor buffer tank, 9 is the air compressor, 10 is the first condenser, 11 is the water ring vacuum pump, 12 is the first vacuum buffer tank, 13 is the second vacuum buffer tank, 14 is the second condenser, 15 is the flame arrester, 16 is the first heating jacket, 17 is the second heating jacket, 18 is the condensation coil, 19 is the hot water pump, 20 is the hot water tank, 21 is the chiller. Detailed Embodiments

[0027] The present utility model will be further described in detail below in conjunction with the drawings and the specific embodiments:

[0028] This embodiment aims to provide a subcritical low-temperature extraction flexible processing complete set of equipment, which is mainly used for subcritical low-temperature extraction of vegetable oil and addresses the problem that the extraction solvent remaining after subcritical low-temperature extraction is difficult to recycle.

[0029] The subcritical low-temperature extraction flexible processing complete set of equipment, as Figure 1, including an extraction tank 1, an evaporation tank 2, a first solvent tank 3, a second solvent tank 4, an exhaust pipeline 5, a high-pressure recovery system, an atmospheric-pressure recovery system, a heating water circuit 6, and a condensation water circuit 7.

[0030] In this embodiment, the extractant mainly includes R134a solvent, No. 4 solvent, and No. 6 solvent. There are two groups of the first solvent tanks 3, which are respectively used to store R134a solvent and No. 4 solvent, and there is one group of the second solvent tanks, which is used to store No. 6 solvent; the R134a solvent and No. 4 solvent change from gaseous state to liquid state under the conditions of about 70 degrees and a pressure of 0.4 MPa, while the No. 6 solvent changes from gaseous state to liquid state under the conditions of atmospheric pressure and a temperature above 68 degrees.

[0031] The discharge ports of the two groups of the first solvent tanks 3 and the discharge port of the second solvent tank 4 are respectively connected to the extraction tank 1 through pipelines by valves, for inputting the extractant into the extraction tank 1, and the liquid discharge port of the extraction tank 1 is connected to the liquid inlet of the evaporation tank 2 through a pipeline; only one extractant is input during each round of extraction, and the corresponding pipelines are all switched through valves.

[0032] The high-pressure recovery system includes a compressor buffer tank 8, an air compressor 9, and a first condenser 10 that are connected in sequence through pipelines. The high-pressure recovery system is mainly used to recover R134a solvent and No. 4 solvent; the exhaust ports of the extraction tank 1 and the evaporation tank 2 are both connected in sequence through pipelines by valves to the compressor buffer tank 8, the air compressor 9, and the first condenser 10; the output port of the first condenser 10 is connected to the first solvent tank 3 through a pipeline.

[0033] The atmospheric-pressure recovery system includes a water ring vacuum pump 11 and a first vacuum buffer tank 12 that are connected through pipelines, and is mainly used to recover No. 6 solvent.

[0034] The exhaust ports of the extraction tank 1 and the evaporation tank 2 are both connected in sequence through pipelines by valves to the water ring vacuum pump 11 and the first vacuum buffer tank 12; the output port of the first vacuum buffer tank 12 is connected to the second solvent tank 4 through a pipeline.

[0035] The water ring vacuum pump 11, the first solvent tank 3, and the second solvent tank 4 are all connected to the exhaust pipeline 5 through valves, and the output port of the exhaust pipeline 5 is connected to the outside.

[0036] The heating water circuit 6 is connected with a hot water pump 19 and a hot water tank 20, and the heating water circuit 6 exchanges heat with the extraction tank 1 and the evaporation tank 2 respectively; the condensation water circuit 7 is connected with a chiller 21, and the condensation water circuit 7 exchanges heat with the first vacuum buffer tank 12 and the first condenser 10 respectively.

[0037] The working steps of this embodiment are as follows:

[0038] (1) Feeding the extraction tank 1;

[0039] Open the feed valve on the extraction tank 1, close all the other valves on the extraction tank 1, and start feeding the raw material (cake). Stop feeding when the material reaches 60% - 70% of the tank volume, and then close the feed valve.

[0040] (2)Extract the air from the extraction tank 1 and adjust the internal pressure of the extraction tank 1;

[0041] Connect the extraction tank 1, the water ring vacuum pump 11, the second vacuum buffer tank 13, and the exhaust pipe 5 in sequence to form an air extraction system. Turn on the water ring vacuum pump 11, and discharge the internal gas of the extraction tank 1 to the outside through the second vacuum buffer tank 13 and the exhaust pipe 5. When the pressure in the extraction tank 1 reaches -0.075 MPa to -0.08 MPa, close the water ring vacuum pump 11 and the relevant valves of the air extraction system.

[0042] (3)Extraction;

[0043] Connect the first solvent tank 3, the extraction tank 1, and the evaporation tank 2 in sequence. Open the liquid inlet valve of the extraction tank 1 and input an extraction agent into the extraction tank 1. When the solvent level in the extraction tank 1 exceeds the height of the raw material by 50 mm, close the liquid inlet valve, soak the raw material for 20 - 30 minutes, open the liquid outlet valve of the extraction tank 1, and the mixed liquid will flow into the evaporation tank 2 by gravity. The solvent will immediately evaporate in the evaporation tank 2V02. This process uses batch extraction. The number of extraction times: 4 - 5 times, the extraction time for each time: 20 - 30 minutes, the extraction pressure: 0.4 - 0.7 MPa, and the extraction temperature: 35 °C.

[0044] (4)Recover the extraction agent;

[0045] If the current extraction agent is R134a solvent or No. 4 solvent, connect the first solvent tank 3, the extraction tank 1, the evaporation tank 2, the compressor buffer tank 8, the air compressor 9, and the first condenser 10 in sequence. The output port of the second condenser 14 is connected to the first solvent tank 3 to form a high-pressure reflux cycle. Turn on the hot water pump 19 and heat the extraction tank 1 and the evaporation tank 2 through the heating water circuit 6. As the temperature rises and the pressure drops, the residual extraction agent in the extraction tank 1 and the evaporation tank 2 changes from liquid to gas; turn on the air compressor 9 so that the gas passes through the compressor buffer tank 8, the compressor, and the first condenser 10 in sequence; turn on the chiller and cool the first condenser 10 through the condensation water circuit 7, so that the gas changes from gaseous state back to liquid state and flows into the first solvent tank 3 containing the corresponding solvent, realizing reflux and recycling.

[0046] When the current extractant is Solvent No. 6, the first solvent tank 3, the extraction tank 1, the evaporation tank 2, the water ring vacuum pump 11, and the first vacuum buffer tank 12 are connected in sequence. The output port of the first vacuum buffer tank 12 is connected to the second solvent tank 4 to form an atmospheric reflux cycle. Turn on the hot water pump 19, and heat the extraction tank 1 and the evaporation tank 2 through the heating water circuit 6. As the temperature rises and the pressure drops, the residual extractant in the extraction tank 1 and the evaporation tank 2 changes from liquid to gas; turn on the water ring vacuum pump 11 to make the gas flow through the water ring vacuum pump 11 and the first vacuum buffer tank 12 and then reflux to the second solvent tank 4. Turn on the chiller 21 and cool the first vacuum buffer tank 12 through the condensation water circuit 7, so that the gas changes from gaseous state back to liquid state and flows into the second solvent tank 4 containing the corresponding solvent, realizing reflux and recycling.

[0047] When changing to different extractants, it is necessary to synchronously switch to the corresponding pipelines, and different extractants cannot be extracted and recovered simultaneously.

[0048] Furthermore, the first vacuum buffer tank 12 is connected to the compressor buffer tank 8 through a pipeline with a valve, so that in the atmospheric reflux cycle, the unliquefied gas can enter the compressor buffer tank 8 and enter the high-pressure reflux cycle.

[0049] Furthermore, a second vacuum buffer tank 13 is provided on the connecting pipeline between the output port of the water ring vacuum pump 11 and the exhaust pipeline 5, and a valve is provided on the connecting pipeline between the water ring vacuum pump 11 and the second vacuum buffer tank 13.

[0050] Furthermore, the exhaust port of the first solvent tank 3 is connected to the exhaust pipeline 5 through a pipeline, so that other doped gases in the first solvent tank 3 can be discharged; the exhaust port of the second solvent tank 4 is connected to the exhaust pipeline 5 through the second condenser 14 in sequence. The condensation water circuit 7 exchanges heat with the second condenser 14, so that other doped gases in the second solvent tank 4 can be discharged, and the second condenser 14 can condense the discharged gas again to prevent the volatilization of Solvent No. 6.

[0051] Furthermore, a flame arrester 15 is provided at the output port of the exhaust pipeline 5 to improve the safety of gas discharge.

[0052] Further, first heating jackets 16 are provided on the outer surfaces of the first solvent tank 3 and the second solvent tank 4, and the heating water circuit 6 passes through the corresponding first heating jackets 16 to perform heat exchange with the first solvent tank 3 and the second solvent tank 4 respectively; second heating jackets 17 are provided on the outer surfaces of the extraction tank 1 and the evaporation tank 2, and the heating water circuit 6 passes through the corresponding second heating jackets 17 to perform heat exchange with the extraction tank 1 and the evaporation tank 2 respectively. A condensation coil 18 is disposed around the inside of the first vacuum buffer tank 12, and the condensation water circuit 7 passes through the condensation coil 18 to perform heat exchange with the first vacuum buffer tank 12. In other embodiments, other heat exchange methods may also be adopted.

Claims

1. Subcritical low temperature extraction flexible processing equipment, characterized by: It comprises an extraction tank (1), an evaporation tank (2), a first solvent tank (3), a second solvent tank (4), an exhaust pipe (5), a high-pressure recovery system, a normal-pressure recovery system, a heating water circuit (6) and a condensing water circuit (7); The discharge port of the first solvent tank (3) and the discharge port of the second solvent tank (4) are respectively connected to the pipeline of the extraction tank (1) through valves, and the discharge port of the extraction tank (1) is connected to the liquid inlet pipeline of the evaporation tank (2); The high-pressure recovery system comprises a compressor buffer tank (8), an air compressor (9) and a first condenser (10) which are sequentially connected by pipelines; The exhaust port of the extraction tank (1) and the exhaust port of the evaporation tank (2) are connected to the compressor buffer tank (8), the air compressor (9) and the first condenser (10) through pipelines in sequence through valves; the output port pipeline of the first condenser (10) is connected to the first solvent tank (3); The atmospheric pressure recovery system comprises a water ring vacuum pump (11) and a first vacuum buffer tank (12) connected by a pipeline; The exhaust port of the extraction tank (1) and the exhaust port of the evaporation tank (2) are connected to the water ring vacuum pump (11) and the first vacuum buffer tank (12) in sequence through pipelines via valves; the output pipeline of the first vacuum buffer tank (12) is connected to the second solvent tank (4); The water ring vacuum pump (11), the first solvent tank (3), and the second solvent tank (4) are all connected to the exhaust pipe (5) through a valve, and the output port of the exhaust pipe (5) is connected to the outside; The heating water circuit (6) performs heat exchange with the extraction tank (1) and the evaporation tank (2) respectively; The condensation water path (7) performs heat exchange with the first vacuum buffer tank (12) and the first condenser (10) respectively.

2. The subcritical low-temperature extraction flexible processing equipment according to claim 1 is characterized in that: The first vacuum buffer tank (12) is connected to the compressor buffer tank (8) through a valve.

3. The subcritical low-temperature extraction flexible processing equipment according to claim 1 is characterized in that: A second vacuum buffer tank (13) is provided on the connecting pipeline between the output port of the water ring vacuum pump (11) and the exhaust pipe (5), and a valve is provided on the connecting pipeline between the water ring vacuum pump (11) and the second vacuum buffer tank (13).

4. The subcritical low-temperature extraction flexible processing equipment according to claim 1 is characterized in that: The exhaust port of the first solvent tank (3) is connected to the exhaust pipe (5), the exhaust port of the second solvent tank (4) is connected to the second condenser (14) and the exhaust pipe (5) in sequence, and the condensation water path (7) performs heat exchange with the second condenser (14).

5. The subcritical low-temperature extraction flexible processing equipment according to claim 1 is characterized in that: The output port of the exhaust pipe (5) is provided with a flame arrester (15).

6. The subcritical low-temperature extraction flexible processing equipment according to claim 1 is characterized in that: Two groups of the first solvent tanks (3) are provided, and the discharge ports of the two groups of the first solvent tanks (3) are respectively connected to the pipelines of the extraction tank (1) through valves, and the output ports of the first condenser (10) are respectively connected to the pipelines of the two groups of the first solvent tanks (3) through valves.

7. The subcritical low-temperature extraction flexible processing equipment according to claim 1 is characterized in that: The outer surfaces of the first solvent tank (3) and the second solvent tank (4) are both provided with first heating jackets (16), and the heating water path (6) respectively exchanges heat with the first solvent tank (3) and the second solvent tank (4) through the corresponding first heating jackets (16).

8. The subcritical low-temperature extraction flexible processing equipment according to claim 1 is characterized in that: The outer surfaces of the extraction tank (1) and the evaporation tank (2) are both provided with a second heating jacket (17), and the heating water path (6) respectively exchanges heat with the first solvent tank (3) and the second solvent tank (4) through the corresponding second heating jacket (17).

9. The subcritical low-temperature extraction flexible processing equipment according to claim 1, characterized in that: A condensing coil (18) is provided in the first vacuum buffer tank (12), and the condensing water path (7) exchanges heat with the first vacuum buffer tank (12) through the condensing coil (18).

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