Solvent recovery device in organic synthesis tail gas

Abstract

The utility model discloses a solvent recovery device in organic synthesis tail gas, and belongs to the technical field of organic synthesis. The device comprises a water distribution box, a paraffin absorption tower, an oil-rich pump, a heat exchanger, a heater, a desorption tower, an oil-lean pump, a cooler, a condenser, a balance tank, a water absorption tower, a paraffin absorption tower, a water jet vacuum structure and a sealing auger which are sequentially connected through pipelines, a water inlet of the water jet vacuum structure, a water outlet of the water jet vacuum structure, a water outlet of the water absorption tower and a spray liquid inlet of the water absorption tower are connected with the water distribution box through pipelines; the paraffin absorption tower, the oil-rich pump, the heat exchanger, the heater and the desorption tower are sequentially connected through pipelines, the desorption tower, the oil-lean pump, the heat exchanger, the cooler and the paraffin absorption tower are sequentially connected through pipelines, an exhaust port of the desorption tower is connected with the condenser through a pipeline, and a condensate outlet of the condenser is connected with the water distribution box through a pipeline. The device can ensure that the organic content in the discharged tail gas is lower than 0.1% and the possibility of leakage is low.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of organic synthesis, especially relates to a solvent recovery device in organic synthesis tail gas. BACKGROUND

[0002] In organic synthesis, most reactions will use organic solvents. In reaction exhaust, reaction vacuum or leaching tail gas, etc. contain organic solvents, in order to reduce the consumption of organic solvents and reduce environmental pollution. In the prior art, the solvent can be recovered by using a paraffin tail gas recovery system.

[0003] Patent No. CN201120461033.8 discloses a paraffin recovery device, which comprises a vacuum pump, a water tank, an absorption tower, an oil-rich pump, a cooler, a heater, a heat exchanger, an oil-poor pump, a resolving tower, a paraffin storage tank, the vacuum pump is connected with the water tank air inlet, the water tank air outlet is connected with the absorption tower first air inlet and the absorption tower second air inlet respectively, a stop valve is installed before the absorption tower first air inlet, the absorption tower oil outlet is connected with the heat exchanger first oil inlet through a stop valve and an oil-rich pump in sequence, the heat exchanger first oil outlet is connected with the heater oil inlet, the heater oil outlet is connected with the resolving tower oil inlet; the oil-poor pump oil inlet is connected with the resolving tower oil outlet, the paraffin storage tank oil outlet through a stop valve respectively, the oil-poor pump oil outlet is connected with the heat exchanger second oil inlet, the heat exchanger second oil outlet is connected with the cooler oil inlet, and the cooler oil outlet is connected with the absorption tower oil inlet; the water tank side is provided with a water outlet; the absorption tower top is provided with an emptying port, the side is provided with a water inlet and a water outlet; the resolving tower top is provided with a condensing port, the side is provided with a steam outlet and a steam inlet, and the bottom is provided with a steam inlet.

[0004] There are two problems in the prior art:

[0005] First, the content of organic solvent in the treated tail gas may exceed the standard (more than 0.1%);

[0006] Second, the negative pressure is large, which may cause running, leakage, dripping or leakage of the whole system, and the tail gas contains organic solvents, so the tail gas leakage is not allowed. Utility model content

[0007] In order to solve the foregoing problems, the utility model embodiment provides a solvent recovery device in organic synthesis tail gas, which can ensure that the organic content in the discharged tail gas is less than 0.1% and the leakage possibility is low. The technical scheme is as follows:

[0008] This utility model provides a solvent recovery device for organic synthesis tail gas. The device includes a water distribution tank 1, a paraffin absorption tower 2, a rich oil pump 3, a heat exchanger 4, a heater 5, a stripping tower 6, a lean oil pump 7, a cooler 8, a condenser, a balance tank 11, a water absorption tower 10, a water jet vacuum structure 9, and a sealing auger. The cold paraffin inlets of the paraffin absorption tower 2, the rich oil pump 3, and the heat exchanger 4 are sequentially connected via pipelines. The hot paraffin outlet of the heat exchanger 4, the heater 5, and the paraffin inlet of the stripping tower 6 are sequentially connected via pipelines. The paraffin outlet of the stripping tower 6, the lean oil pump 7, and the heat exchanger 4 are connected via pipelines. The paraffin inlet is connected in sequence via pipelines. The cold paraffin outlet of the heat exchanger 4, the cooler 8, and the paraffin absorption tower 2 are connected in sequence via pipelines. The exhaust port of the desorption tower 6 is connected to the condenser via pipelines. The condensate outlet of the condenser is connected to the water distribution tank 1 via pipelines. The balance tank 11, the water absorption tower 10, the paraffin absorption tower 2, the water jet vacuum structure 9, and the sealing auger are connected in sequence via pipelines. The water inlet, the drain outlet, the drain outlet, and the spray liquid inlet of the water jet vacuum structure 9 are all connected to the water distribution tank 1 via pipelines.

[0009] In this embodiment of the present invention, the analytical tower 6 has a steam inlet at its lower part, an exhaust port at its top, and a heating jacket outside; the water absorption tower 10 has an air inlet at its lower part, a drain port at its bottom, an exhaust port at its top, a nozzle at its upper inner part, a collection tray at its lower inner part, and stainless steel packing in its middle inner part; the air inlet of the water absorption tower 10 is connected to the collection tray and is liquid-sealed.

[0010] In this embodiment of the present invention, the water distribution tank 1 is lower than the condenser and the water absorption tower 10, and its water phase outlet is connected to the water inlet of the water jet vacuum structure 9 and the spray liquid inlet of the water absorption tower 10 through a pipeline.

[0011] Specifically, in this embodiment of the present invention, the heat exchanger 4 and the cooler 8 are spiral plate heat exchangers, and the heater 5 is a shell and tube heat exchanger.

[0012] In this embodiment of the invention, the water jet vacuum structure 9 includes a water jet vacuum pump 91, a circulating water tank 92, and a cooking tank 93. The water jet vacuum pump 91 is located directly above the circulating water tank 92. Its air inlet is connected to the exhaust port of the paraffin absorption tower 2 via a pipeline, its water inlet is connected to the circulating water tank 92 via a pipeline, and its drain outlet is connected to the top of the circulating water tank 92 via a pipeline. The water phase outlet of the water distribution tank 1 overflows into the circulating water tank 92. The exhaust port at the top of the circulating water tank 92 is connected to a sealing auger via a pipeline, and the water outlet at its upper part overflows into the cooking tank 93. The drain outlet of the cooking tank 93 is connected to the water distribution tank 1 via a pipeline.

[0013] Preferably, in this embodiment of the invention, U-shaped liquid seal pipes are provided on the pipeline between the water distribution tank 1 and the circulating water tank 92 and on the pipeline between the circulating water tank 92 and the cooking tank 93.

[0014] Specifically, in this embodiment of the invention, the pumping capacity of the water jet vacuum pump 91 is 20-45 m³ / h. 3 The operating rate is 18-21 kPa, the ultimate vacuum degree is 18-21 kPa, and the power is 3.0-5.5 kW; the volume of the circulating water tank 92 is 0.8-1.5 m³. 3 .

[0015] In this embodiment of the invention, the sealing auger is filled with porous absorbent filler.

[0016] The beneficial effects of the technical solution provided by this utility model embodiment are as follows: This utility model embodiment provides a solvent recovery device for organic synthesis tail gas. Through multiple absorption processes, it ensures that the organic solvent content in the emitted tail gas does not exceed the standard (less than 1.0%). The multiple absorption processes include: absorption by a water absorption tower, absorption by a paraffin absorption tower, spray absorption by a water jet vacuum pump, and absorption by the packing material in a sealed auger. The water jet vacuum pump keeps the entire device under slight negative pressure, reducing the possibility of equipment leakage. The water distribution tank has multiple functions: first, to supply water to the water absorption tower; second, to separate oil and water in the spray liquid of the water absorption tower; third, to separate oil and water in the condensate; and fourth, to supply water to the jet vacuum pump and receive the sprayed water. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the solvent recovery device in the organic synthesis tail gas in this embodiment;

[0018] Figure 2 This is a partial structural diagram of a solvent recovery device in organic synthesis tail gas.

[0019] Figure 3 This is a schematic diagram of the water jet vacuum structure.

[0020] Figure 4 This is a schematic diagram of a water jet vacuum structure.

[0021] In the diagram: 1. Water tank, 2. Paraffin absorption tower, 3. Rich oil pump, 4. Heat exchanger, 5. Heater, 6. Desorption tower, 7. Lean oil pump, 8. Cooler, 9. Water jet vacuum structure, 10. Water absorption tower, 11. Balance tank.

[0022] 91 Water jet vacuum pump, 92 Circulating water tank, 93 Cooking tank. Detailed Implementation

[0023] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0024] Example 1

[0025] See Figures 1-4 Example 1 provides a solvent recovery device for organic synthesis tail gas. This device includes a water distribution tank 1, a paraffin absorption tower 2, a rich oil pump 3, a heat exchanger 4, a heater 5, a stripping tower 6, a lean oil pump 7, a cooler 8, a condenser (not shown), a balance tank 11, a water absorption tower 10, a water jet vacuum structure 9, and a sealing auger (not shown, used for sealing and venting). The balance tank 11, water absorption tower 10, paraffin absorption tower 2, water jet vacuum structure 9, and sealing auger are connected sequentially via pipelines to treat the tail gas. The water absorption tower 10 not only achieves spray absorption (mainly for absorbing water-soluble components) but also cools the tail gas, facilitating subsequent treatment in the paraffin absorption tower 2. The water jet vacuum structure 9 not only achieves vacuuming but also spray absorption. The paraffin outlet at the bottom of the paraffin absorption tower 2, the rich oil pump 3, and the cold paraffin inlet of the heat exchanger 4 (which heats the paraffin through heat exchange with hot paraffin) are connected in sequence via pipelines to heat the solvent-rich paraffin. The hot paraffin outlet of the heat exchanger 4, the heater 5 (which can be steam-heated), and the paraffin inlet at the top of the stripping tower 6 are connected in sequence via pipelines. The paraffin outlet at the bottom of the stripping tower 6, the lean oil pump 7, and the hot paraffin inlet of the heat exchanger 4 are connected in sequence via pipelines to cool the paraffin. The cold paraffin outlet of the heat exchanger 4, the cooler 8 (which can be cooled by cooling water), and the paraffin inlet at the top of the paraffin absorption tower 2 are connected in sequence via pipelines. The exhaust port of the stripping tower 6 is connected to the condenser via pipelines, and the condensate outlet of the condenser is connected to the water distribution tank 1 via pipelines. The water inlet (transported by a pump), the water outlet of the water jet vacuum structure 9, the water outlet of the water absorption tower 10, and the spray liquid inlet (transported by a pump) of the water absorption tower 10 are all connected to the water distribution tank 1 via pipelines.

[0026] In this embodiment of the invention, the analytical tower 6 has a steam inlet at its lower part, an exhaust port at its top, a heating jacket outside, a paraffin wax outlet at its bottom, and a paraffin wax inlet at its upper part. The water absorption tower 10 has an air inlet at its lower part, a drain outlet at its bottom, an exhaust port at its top, a nozzle at its upper inner part, a collection tray at its lower inner part, and stainless steel packing in its middle inner part. The air inlet of the water absorption tower 10 leads into the collection tray and is liquid-sealed. In the water absorption tower 10, the exhaust gas and the spray liquid come into countercurrent contact. The paraffin wax absorption tower 2 has an air inlet at its lower part (connected to the water absorption tower 10), a paraffin wax inlet at its upper part (connected to the cooler), a paraffin wax outlet at its bottom (connected to the rich oil pump 3), and an exhaust port at its top (connected to the water jet vacuum structure 9). In the paraffin wax absorption tower 2, low-temperature paraffin wax comes into countercurrent contact with the exhaust gas.

[0027] In this embodiment of the present invention, the water distribution tank 1 is lower than the condenser and the water absorption tower 10, and its water phase outlet is connected to the water inlet of the water jet vacuum structure 9 and the spray liquid inlet of the water absorption tower 10 through a pipeline.

[0028] Specifically, in this embodiment of the present invention, the heat exchanger 4 and the cooler 8 are spiral plate heat exchangers, and the heater 5 is a shell and tube heat exchanger.

[0029] In this embodiment of the invention, the sealing auger is filled with a porous absorbent filler to absorb the solvent. Specifically, the absorbent filler can be granular activated carbon.

[0030] Example 2

[0031] See Figures 3-4 Example 2 provides a solvent recovery device for organic synthesis tail gas, whose structure is basically the same as that of Example 1, except that the water jet vacuum structure 9 in this example includes a water jet vacuum pump 91, a circulating water tank 92, and a digester 93. The water jet vacuum pump 91 is located directly above the circulating water tank 92. Its air inlet is connected to the exhaust port of the paraffin absorption tower 2 through a pipeline, its water inlet is connected to the circulating water tank 92 through a pipeline, and its drain outlet (which also serves as an exhaust port) is connected to the top of the circulating water tank 92 through a pipeline. The aqueous phase outlet of the water separator 1 (higher than the corresponding inlet of the circulating water tank 92) overflows into the circulating water tank 92. The exhaust port at the top of the circulating water tank 92 is connected to a sealing auger through a pipeline, and its upper outlet (higher than the corresponding inlet of the digester 93) overflows into the digester 93. The drain outlet of the digester 93 is connected to the water separator 1 through a pipeline, and it is used to cook and separate the organic solvent in the aqueous phase. In this embodiment, the pumping capacity of the water jet vacuum pump 91 is 20-45m³. 3 The operating rate is 18-21 kPa, and the power output is 3.0-5.5 kW. The volume of the circulating water tank 92 is 0.8-1.5 m³. 3 .

[0032] Preferably, in this embodiment of the invention, U-shaped liquid seal pipes are provided on the pipeline between the water distribution tank 1 and the circulating water tank 92, and on the pipeline between the circulating water tank 92 and the cooking tank 93, to prevent cross-contamination of air.

[0033] Example 3

[0034] Example 3 provides a solvent recovery device for organic synthesis tail gas, which has a structure that is basically the same as that of Example 2, except that the pumping capacity of the water jet vacuum pump 91 in this example is 20-45m³. 3 / h, adjustable as needed. Ultimate vacuum is 20 kPa, power is 4.0 kW; the volume of the circulating water tank 92 is 1.2 m³. 3 .

[0035] Example 4

[0036] Example 4 provides a method for solvent recovery from organic synthesis tail gas, using the solvent recovery device for organic synthesis tail gas described in Examples 1, 2, or 3. The process of this method is as follows:

[0037] After the exhaust gas is pressure balanced by the balance tank 11, it enters from the bottom of the water absorption tower 10 and comes into countercurrent contact with the exhaust gas. The solvent in the exhaust gas is cooled and partially absorbed. The mixture of solvent and water enters the water separator 1 from the bottom of the water absorption tower 10 for oil-water separation. The non-condensable gas discharged from the water absorption tower 10 enters from the bottom of the paraffin absorption tower 2 and comes into countercurrent contact with the cold paraffin entering from the top of the paraffin absorption tower 2. The solvent basically enters the paraffin. The low-temperature paraffin containing solvent is heated to 110-125°C by the heat exchanger 4 (exchanging heat with the high-temperature paraffin from the desorption tower 6) and the heater 5 and then sent to the desorption tower 6. In the desorption tower, water vapor is introduced, and the solvent and water vapor are discharged from the top of the desorption tower 6. After being condensed by the condenser, the condensate (solvent and water) enters the water separator 1 for oil-water separation. The desorbed paraffin is sent to the paraffin absorption tower 2. The exhaust gas output from the paraffin absorption tower 2 is absorbed again by the water jet vacuum pump 91 and finally sent to the sealed auger for absorption and venting. At the same time, the water jet vacuum pump 91 creates a slight negative pressure inside the device, allowing the exhaust gas to flow.

[0038] In this patent, pumps, valves, or flow meters may be installed on the pipelines between the various structures as needed.

[0039] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A device for recovering solvent from organic synthesis tail gas, comprising a water distribution tank (1), a paraffin absorption tower (2), a rich oil pump (3), a heat exchanger (4), a heater (5), a desorption tower (6), a lean oil pump (7), a cooler (8) and a condenser, the cold paraffin inlet of the paraffin absorption tower (2), the rich oil pump (3) and the heat exchanger (4) being connected in sequence by pipelines, the hot paraffin outlet of the heat exchanger (4), the heater (5) and the paraffin inlet of the desorption tower (6) being connected in sequence by pipelines, the paraffin outlet of the desorption tower (6), the lean oil pump (7) and the hot paraffin inlet of the heat exchanger (4) being connected in sequence by pipelines, the cold paraffin outlet of the heat exchanger (4), the cooler (8) and the paraffin absorption tower (2) being connected in sequence by pipelines, the exhaust outlet of the desorption tower (6) being connected to the condenser by a pipeline, and the condensate outlet of the condenser being connected to the water distribution tank (1) by a pipeline; characterized in that, the device further comprises a balance tank (11), a water absorption tower (10), a water jet vacuum structure (9) and a sealing auger, the balance tank (11), the water absorption tower (10), the paraffin absorption tower (2), the water jet vacuum structure (9) and the sealing auger being connected in sequence by pipelines, the water inlet of the water jet vacuum structure (9), the water outlet of the water jet vacuum structure (9), the water outlet of the water absorption tower (10) and the spray liquid inlet of the water absorption tower (10) being connected to the water distribution tank (1) by pipelines.

2. The apparatus for recovery of solvents from organic synthesis off-gases according to claim 1, characterized in that, The lower part of the desorption tower (6) is provided with a vapor inlet, the top part is provided with an exhaust outlet, and a heating jacket is arranged outside; the lower part of the water absorption tower (10) is provided with an air inlet, the bottom part is provided with a water outlet, the top part is provided with an exhaust outlet, the inner upper part is provided with a spray head, the inner lower part is provided with a collection tray, and the inner middle part is provided with a stainless steel filler; the air inlet of the water absorption tower (10) is connected to the collection tray and is liquid sealed.

3. The apparatus for recovery of solvents from organic synthesis off-gases according to claim 1, characterized in that, The water distribution tank (1) is lower than the condenser and the water absorption tower (10), and the water phase outlet thereof is connected to the water inlet of the water jet vacuum structure (9) and the spray liquid inlet of the water absorption tower (10) by pipelines.

4. The solvent recovery unit in organic synthesis off-gas according to claim 1, characterized in that, The heat exchanger (4) and the cooler (8) are spiral plate heat exchangers, and the heater (5) is a tube heat exchanger.

5. The solvent recovery unit in organic synthesis off-gas according to claim 1, characterized in that, The water jet vacuum structure (9) comprises a water jet vacuum pump (91), a circulating water tank (92) and a steaming tank (93); the water jet vacuum pump (91) is located directly above the circulating water tank (92), the air inlet thereof is connected to the exhaust outlet of the paraffin absorption tower (2) by a pipeline, the water inlet thereof is connected to the circulating water tank (92) by a pipeline, and the water outlet thereof is connected to the top of the circulating water tank (92) by a pipeline; the water phase outlet of the water distribution tank (1) overflows into the circulating water tank (92), the air outlet at the top of the circulating water tank (92) is connected to the sealing auger by a pipeline, and the water outlet at the upper part thereof overflows into the steaming tank (93), and the water outlet of the steaming tank (93) is connected to the water distribution tank (1) by a pipeline.

6. The solvent recovery unit from organic synthesis off-gas according to claim 5, characterized in that, U-shaped liquid seal pipes are arranged on the pipelines between the water distribution tank (1) and the circulating water tank (92) and between the circulating water tank (92) and the steaming tank (93).

7. The solvent recovery unit from organic synthesis off-gas according to claim 5, characterized in that, The water jet vacuum pump (91) has a pumping capacity of 20-45 m 3 / h, an ultimate vacuum of 18-21 kPa, and a power of 3.0-5.5 kW; the circulating water tank (92) has a volume of 0.8-1.5 m 3 .

8. The solvent recovery unit in organic synthesis off-gas according to claim 1, characterized in that, The sealing auger is filled with an absorbent filler having pores.

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