Normal hexane recovery system for grain and oil leaching workshop

Abstract

The utility model provides an n-hexane recovery system for a grain and oil leaching workshop, which comprises an oil mist purification spray tower, a heat exchanger, a first adsorption tower, a second adsorption tower, a third adsorption tower, a condenser, an oil-water separator, an n-hexane delivery pump and a negative pressure fan, the oil mist purification spray tower comprises a demisting section, an upper supporting grid plate, an upper spraying section, a middle supporting grid plate, a lower spraying section, a bottom supporting grid plate, a liquid collecting section and a spraying device from top to bottom, a gas outlet is formed in the top of the demisting section, a gas inlet is formed in one side of the liquid collecting section, the gas outlet is connected with the heat exchanger, and the spraying device is connected with the heat exchanger. An outlet of the heat exchanger is respectively connected with a first adsorption tower, a second adsorption tower and a third adsorption tower through pipelines, and the connecting bottoms of the first adsorption tower, the second adsorption tower and the third adsorption tower are respectively provided with pipelines connected with a condenser. The system disclosed by the utility model is high in normal hexane recovery rate, can simultaneously and continuously perform adsorption and desorption, can prevent oil mist in waste gas from influencing an adsorbent, and can stably and continuously operate for a long period.

Description

Technical Field

[0001] The utility model belongs to the field of environmental protection equipment, and in particular relates to a normal hexane recovery system for a grain and oil leaching workshop. Background Art

[0002] The grain and oil extraction workshop uses n-hexane as the extraction solvent. With the improvement of environmental protection requirements, the emission requirements for non-methane total hydrocarbons are increasing. The treatment of non-methane total hydrocarbons includes activated carbon adsorption, low-temperature plasma technology, photocatalytic oxygen process, biological treatment, combustion method and other technologies. The environmental protection department encourages the priority use of recycling technology. Traditional activated carbon adsorption technology is prone to chemical reactions after adsorbing chlorinated hydrocarbons due to the catalytic effect of metals and other miscellaneous elements on the surface of activated carbon, and adsorption and desorption cannot be carried out at the same time. In addition, due to the influence of heavy component oil mist in the exhaust gas, it is easy to block the adsorbent pores, making the adsorbent inactive and reducing the adsorption capacity. The adsorbent needs to be replaced frequently, and the operating cost is high. Utility Model Content

[0003] In order to solve the above technical problems, the utility model discloses a n-hexane recovery system for a grain and oil leaching workshop, which has a high n-hexane recovery rate, and adsorption and desorption can be carried out simultaneously and continuously, which can prevent the influence of oil mist in the exhaust gas on the adsorbent, and the system can operate stably and continuously for a long period of time.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A n-hexane recovery system for a grain and oil extraction workshop comprises an oil mist purification spray tower, a heat exchanger, a first adsorption tower, a second adsorption tower, a third adsorption tower, a condenser, an oil-water separator, a n-hexane delivery pump, and a negative pressure fan. The oil mist purification spray tower comprises a demisting section, an upper supporting grid plate, an upper spraying section, a middle supporting grid plate, a lower spraying section, a bottom supporting grid plate, a liquid collecting section, and a spraying device from top to bottom. The demisting section has a gas outlet at the top and a demister installed inside. The upper spraying section is filled with a first packing layer, and the lower spraying section is filled with a second packing layer. A gas inlet is opened on one side of the liquid collecting section, a liquid level gauge is provided in the middle, and a liquid outlet and a fresh water replenishment port are provided at the bottom. The spraying device comprises a centrifugal water pump, An upper spray pipe, an upper nozzle, a lower spray pipe, and a lower nozzle, wherein the upper spray pipe is located at the lower part of the upper supporting grid plate, one end of which is connected to the centrifugal water pump outlet through a pipeline, the upper nozzle is installed on the upper spray pipe, the lower spray pipe is located at the lower part of the middle supporting grid plate, one end of which is connected to the centrifugal water pump outlet through a pipeline, the gas outlet is connected to the heat exchanger, the heat exchanger outlet is respectively connected to the first adsorption tower, the second adsorption tower, and the third adsorption tower through pipelines, the first adsorption tower, the second adsorption tower, and the third adsorption tower are connected to the condenser at the bottom with pipelines respectively, the condenser is provided with a condensate outlet at the bottom, and a non-condensable gas outlet is provided at the upper part, the condensate outlet is connected to the oil-water separator through a pipeline, and the non-condensable gas outlet is connected to the negative pressure fan through a pipeline.

[0006] Furthermore, the first adsorption tower includes an upper tower body, a middle tower body, and a lower tower body. The upper tower body is provided with an air inlet at the top, the middle tower body is filled with adsorbent, the lower tower body is provided with an air outlet at the side, and a liquid outlet at the bottom. The air inlet is connected to the heat exchanger outlet through a pipeline, and the air outlet is connected to the negative pressure fan and the air inlet through a pipeline.

[0007] Furthermore, the structures of the second adsorption tower and the third adsorption tower are the same as those of the first adsorption tower, and the three are connected by pipelines, and each connecting pipeline is provided with a solenoid valve.

[0008] Furthermore, the heat exchanger is a shell and tube heat exchanger, which is provided with a refrigerant inlet and a refrigerant outlet, and the refrigerant exchanges heat with the gas exiting the oil mist purification spray tower in countercurrent.

[0009] Furthermore, the upper spray pipe and the lower spray pipe are arranged in a concentric ring shape in the oil mist purification spray tower, and the upper nozzles and the lower nozzles are in multiple numbers, which are evenly arranged on the upper spray pipe and the lower spray pipe respectively.

[0010] Furthermore, a one-way valve is installed on the gas inlet.

[0011] Furthermore, a n-hexane discharge port is provided at the bottom of the oil-water separator, and a n-hexane exhaust port is provided at the top. The n-hexane discharge port is connected to the n-hexane delivery pump, and the n-hexane exhaust port is connected to the negative pressure fan.

[0012] The n-hexane recovery system of the grain and oil extraction workshop described in the utility model first uses an oil mist purification spray tower to capture the heavy component oil mist of the exhaust gas, and the heavy component oil mist is captured by the double-layer fillers of the upper spray section and the lower spray section. The oil enters the liquid collection section at the bottom of the oil mist purification spray tower with the liquid, and can be recycled by spraying water under the action of a centrifugal water pump. After a certain cycle, it is discharged and supplemented with fresh water. The gas after the oil mist is removed enters the demister at the top of the oil mist purification spray tower, and enters the heat exchanger for gas cooling after removing the spray water droplets. The cooled gas enters the adsorption tower. The adsorption process is to first enter the first adsorption tower for adsorption, and the exhaust gas after adsorption by the first adsorption tower enters the second adsorption tower for re-adsorption. When the VOCs concentration in the exhaust gas at the outlet of the second adsorption tower reaches a certain value, the first adsorption tower adsorption is stopped. Switch to the second adsorption tower and the third adsorption tower for adsorption, and the first adsorption tower enters the desorption process. The switching time of the adsorption tower is based on the previous continuous sampling detection of the inlet concentration and the outlet concentration of the device. The higher inlet concentration and the non-penetration time are used to set the adsorption time and switching cycle. After the adsorption is stopped, steam is introduced from the top of the adsorption tower. The saturated steam under desorption is condensed by the two-stage condenser and then enters the oil-water separator. The non-condensable gas that cannot be condensed returns to the front exhaust fan for adsorption again. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a structural schematic diagram of a normal hexane recovery system in a grain and oil extraction workshop according to the utility model;

[0014] Figure 2 This is a schematic diagram of the structure of the oil mist purification spray tower described in the utility model;

[0015] Figure 3 This is a schematic diagram of the structure of the first adsorption tower described in the utility model.

[0016] Among them, 1-oil mist purification spray tower, 2-heat exchanger, 3-first adsorption tower, 4-second adsorption tower, 5-third adsorption tower, 6-condenser, 7-oil-water separator, 8-n-hexane delivery pump, 9-negative pressure fan, 101-demist section, 102-upper support grid, 103-upper spray section, 104-middle support grid, 105-lower spray section, 106-bottom support grid, 107-liquid collection section, 108-spraying device, 1011-gas outlet, 1012-demister, 1031-first packing layer, 1051-second packing layer, 1 071-gas inlet, 1072-liquid level meter, 1073-liquid outlet, 1074-fresh water replenishment port, 1081-centrifugal water pump, 1082-upper spray pipe, 1083-upper nozzle, 1084-lower spray pipe, 1085-lower nozzle, 601-condensate outlet, 602-non-condensable gas outlet, 301-upper tower body, 302-middle tower body, 303-lower tower body, 3011-air inlet, 3021-adsorbent, 3031-air outlet, 3032-liquid outlet, 701-n-hexane discharge port, 702-n-hexane exhaust port. DETAILED DESCRIPTION

[0017] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments.

[0018] like Figure 1-Figure 3As shown, a normal hexane recovery system for a grain and oil extraction workshop includes an oil mist purification spray tower 1, a heat exchanger 2, a first adsorption tower 3, a second adsorption tower 4, a third adsorption tower 5, a condenser 6, an oil-water separator 7, a normal hexane delivery pump 8, and a negative pressure fan 9. The oil mist purification spray tower 1 includes a demisting section 101, an upper support grid 102, an upper spraying section 103, a middle support grid 104, a lower spraying section 105, a bottom support grid 106, a liquid collecting section 107, and a spraying device 108 from top to bottom. The top of the demisting section 101 is opened with a gas The outlet 1011 is equipped with a demister 1012 inside, the upper spray section 103 is filled with a first packing layer 1031, the lower spray section 105 is filled with a second packing layer 1051, a gas inlet 1071 is opened on one side of the liquid collection section 107, a liquid level gauge 1072 is provided in the middle, a liquid outlet 1073 and a fresh water replenishment port 1074 are provided at the lower part, and a one-way valve is installed on the gas inlet 1071. The spray device 108 includes a centrifugal water pump 1081, an upper spray pipe 1082, an upper nozzle 1083, and a lower spray pipe 108 4. Lower nozzle 1085, the upper spray pipe 1082 is located at the lower part of the upper support grid plate 102, one end of which is connected to the outlet of the centrifugal water pump 1081 through a pipeline, the upper nozzle 1083 is installed on the upper spray pipe 1082, the lower spray pipe 1084 is located at the lower part of the middle support grid plate 104, one end of which is connected to the outlet of the centrifugal water pump 1081 through a pipeline, the gas outlet 1011 is connected to the heat exchanger 2, and the outlet of the heat exchanger 2 is connected to the first adsorption tower 3, the second adsorption tower 4, and the third adsorption tower 5 through pipelines, respectively, the first adsorption tower 3, the second adsorption tower 4, and the third adsorption tower 5 Tower 4 and the third adsorption tower 5 are connected to the condenser 6 through pipes at the bottom, the condenser 6 has a condensate outlet 601 at the bottom, and a non-condensable gas outlet 602 at the top, the condensate outlet 601 is connected to the oil-water separator 7 through a pipe, and the non-condensable gas outlet 602 is connected to the negative pressure fan 9 through a pipe; the oil-water separator 7 has a n-hexane discharge port 701 at the bottom, and a n-hexane exhaust port 702 at the top, the n-hexane discharge port 701 is connected to the n-hexane delivery pump 8, and the n-hexane exhaust port 702 is connected to the negative pressure fan 9.

[0019] The first adsorption tower 3 includes an upper tower body 301, a middle tower body 302, and a lower tower body 303. The upper tower body 301 is provided with an air inlet 3011 at the top, the middle tower body 302 is filled with an adsorbent 3021, the lower tower body 303 is provided with an air outlet 3031 on the side, and a liquid outlet 3032 at the bottom. The air inlet 3011 is connected to the outlet of the heat exchanger 3 through a pipeline, and the air outlet 3031 is connected to the negative pressure fan 9 and the air inlet 3011 through a pipeline; the second adsorption tower 4 and the third adsorption tower 5 have the same structure as the first adsorption tower, and the three are connected by pipelines, and each connecting pipeline is provided with a solenoid valve.

[0020] The heat exchanger 2 is a shell and tube heat exchanger, which is provided with a refrigerant inlet and a refrigerant outlet, and the refrigerant and the gas exiting the oil mist purification spray tower 1 are countercurrently exchanged with each other; the upper spray pipe 1082 and the lower spray pipe 1084 are arranged in a concentric ring shape in the oil mist purification spray tower 1, and the upper nozzles 1083 and the lower nozzles 1085 are in plurality, and are evenly arranged on the upper spray pipe 1082 and the lower spray pipe 1084, respectively.

[0021] A person skilled in the art should understand that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A n-hexane recovery system for a grain and oil leaching workshop, characterized in that: The oil mist purification spray tower comprises an oil mist purification spray tower, a heat exchanger, a first adsorption tower, a second adsorption tower, a third adsorption tower, a condenser, an oil-water separator, a n-hexane delivery pump, and a negative pressure fan. The oil mist purification spray tower comprises a demisting section, an upper supporting grid plate, an upper spraying section, a middle supporting grid plate, a lower spraying section, a bottom supporting grid plate, a liquid collecting section, and a spraying device from top to bottom. The demisting section has a gas outlet at the top and a demister installed inside. The upper spraying section is filled with a first packing layer, and the lower spraying section is filled with a second packing layer. A gas inlet is opened on one side of the liquid collecting section, a liquid level meter is provided in the middle, and a liquid outlet and a fresh water replenishment port are provided at the bottom. The spraying device comprises a centrifugal water pump, an upper spray pipe, and an upper nozzle. , lower spray pipe, lower nozzle, the upper spray pipe is located at the lower part of the upper supporting grid, one end of which is connected to the centrifugal water pump outlet through a pipe, the upper nozzle is installed on the upper spray pipe, the lower spray pipe is located at the lower part of the middle supporting grid, one end of which is connected to the centrifugal water pump outlet through a pipe, the gas outlet is connected to the heat exchanger, the heat exchanger outlet is connected to the first adsorption tower, the second adsorption tower and the third adsorption tower respectively through pipes, the first adsorption tower, the second adsorption tower and the third adsorption tower are connected to the condenser at the bottom respectively, a condensate outlet is provided at the bottom of the condenser, a non-condensable gas outlet is provided at the upper part, the condensate outlet is connected to the oil-water separator through a pipe, and the non-condensable gas outlet is connected to the negative pressure fan through a pipe.

2. A n-hexane recovery system for grain and oil extraction workshop according to claim 1, characterized in that: The first adsorption tower includes an upper tower body, a middle tower body, and a lower tower body. The upper tower body is provided with an air inlet at the top, the middle tower body is filled with adsorbent, the lower tower body is provided with an air outlet at the side, and a liquid outlet at the bottom. The air inlet is connected to the heat exchanger outlet through a pipeline, and the air outlet is connected to the negative pressure fan and the air inlet through a pipeline.

3. The n-hexane recovery system for grain and oil extraction workshop according to claim 1, characterized in that: The second adsorption tower and the third adsorption tower have the same structure as the first adsorption tower. The three are connected by pipelines, and each connecting pipeline is provided with a solenoid valve.

4. The n-hexane recovery system for grain and oil extraction workshop according to claim 1, characterized in that: The heat exchanger is a shell and tube heat exchanger, which is provided with a refrigerant inlet and a refrigerant outlet, and the refrigerant exchanges heat with the gas exiting the oil mist purification spray tower in countercurrent.

5. The n-hexane recovery system for grain and oil extraction workshop according to claim 1, characterized in that: The upper spray pipe and the lower spray pipe are arranged in a concentric ring shape in the oil mist purification spray tower. The upper spray heads and the lower spray heads are in multiple numbers and are evenly arranged on the upper spray pipe and the lower spray pipe respectively.

6. The n-hexane recovery system for grain and oil extraction workshop according to claim 1, characterized in that: A one-way valve is installed on the gas inlet.

7. The n-hexane recovery system for grain and oil extraction workshop according to claim 1, characterized in that: The oil-water separator is provided with a n-hexane discharge port at the bottom and a n-hexane exhaust port at the top. The n-hexane discharge port is connected to a n-hexane delivery pump, and the n-hexane exhaust port is connected to a negative pressure fan.

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