JP5412817B2 - Solvent recovery device - Google Patents

Description

  The present invention relates to a solvent recovery apparatus that recovers a water-soluble solvent contained in exhaust gas discharged from a factory.

  Conventionally, the following apparatus has been proposed as an apparatus for recovering a water-soluble solvent from an exhaust gas containing a water-soluble solvent having a boiling point higher than that of water (the “gas” in the present application).

  That is, N-methyl-2-pyrrolidone (hereinafter referred to as “NMP”) is exemplified as the water-soluble solvent, the exhaust gas containing NMP is cooled by a concentrator, and the duct (the “water spray part” of the present application corresponds). ) To the container (the “gas-liquid separator” of the present application). A nozzle is provided in the duct. An aqueous solution or water collected in the container (hereinafter referred to as “aqueous solution”) is sprayed from the nozzle and comes into contact with the exhaust gas.

  Thereafter, the exhaust gas introduced into the container exchanges heat with the heat medium circulating in the concentrator provided in the container, and is further cooled. As a result, the exhaust gas that has come into contact with the aqueous solution or the like is promoted to gas-liquid separation and generates an aqueous solution in which NMP is dissolved (see, for example, Patent Document 1).

  In order to recover an aqueous solution in which more NMP is dissolved, the following requirements are required in the duct in which the exhaust gas and the aqueous solution contact.

  First, it is necessary to sufficiently contact the exhaust gas and the aqueous solution.

  That is, in order to collect more NMP contained in the exhaust gas as an aqueous solution, it is necessary that more NMP is dissolved in the aqueous solution or the like in the duct, which is a pre-process of the container. If NMP is more dissolved in an aqueous solution or the like, it is easier to recover NMP as an aqueous solution by cooling the aqueous solution in which NMP is dissolved in a container and performing gas-liquid separation.

  Next, more exhaust gas needs to be sent into the container without the exhaust gas coming into contact with the aqueous solution or the like remaining in the duct.

That is, the aqueous solution or the like sprayed from the nozzle drifts as mist-like water droplets in the duct. Exhaust gas that has come into contact with the mist-like water droplets is heavier than before being in contact with the water droplets. If the weight is appropriate, it is sent to the container by the flow of exhaust gas flowing in the duct. However, when it contacts too much with a water droplet, it cannot reach a container and there exists a possibility of staying in a duct. The exhaust gas staying in the duct may be liquefied in the duct by adhering to the inner wall surface of the duct or falling in the duct.
JP 2008-168290 A

  By the way, in order to make exhaust gas, aqueous solution, etc. contact sufficiently, the space which exhaust gas, aqueous solution, etc. contact must be expanded, or the time for exhaust gas, aqueous solution, etc. to contact must be lengthened.

  In order to realize this requirement, the length of the duct is increased to widen the space where the exhaust gas and the aqueous solution contact, or the exhaust gas flow rate is decreased so that the exhaust gas and the aqueous solution contact each other. It is conceivable to lengthen the time to do.

  On the other hand, in order to send the exhaust gas in contact with the water droplets into the container as much as possible without staying in the duct, the length of the duct is not long and the flow rate of the exhaust gas should be fast.

  The present invention satisfies these conflicting requirements, and an object of the present invention is to recover more water-soluble solvent by sending more exhaust gas sufficiently in contact with an aqueous solution or the like into the container.

In order to achieve the above-mentioned object, the present invention cools the water spray unit that makes water droplets contact with a gas containing a water-soluble solvent having a boiling point higher than that of water, and the gas that contacts the water droplets in the water spray unit. and a gas-liquid separator, the water spray portion includes a suction port for sucking the gas, a discharge port for discharging the gas in contact with the water droplets into the gas-liquid separator, and the suction port and the discharge port and a gas flow path that connects, wherein the gas flow path, a nozzle for jetting the water droplet, between the nozzle and the suction port, the gas flow between the nozzle and the discharge port and a narrowed portion than the cross-sectional area of the road to reduce the cross-sectional area of the gas flow path between the nozzle and the suction port is provided, the diaphragm portion, the guide plate provided on the inner wall surface forming said gas flow paths made, said guide plate, around the inside wall and one end connected to the inner wall surface Attached to cover Te, and the other end is mounted inclined to the other end in the structure remote from the inner wall so as to be positioned upward from the end, the water spray portion is a straight tube, the lower From above, the suction port, the throttle unit, the nozzle, and the discharge port are arranged in this order, and include a concentrator, the concentrator includes a cooling unit that exchanges heat between the aqueous solution and the gas, and the cooling unit The gas cooled in the step is sucked into the water spray section through the suction port, and the aqueous solution collected in the gas-liquid separation section is collected in the concentrator through a pipe and flows into the cooling section, The constrictor is provided above the concentrator, a return pipe is provided to connect the constrictor and the cooling unit of the concentrator, and the aqueous solution accumulated in the constrictor is guided to the cooling unit, and the concentrator Is an aqueous solution added by heat exchange between the aqueous solution and the gas. It is that the solvent recovery apparatus which concentrated.

With this apparatus, the resulting aqueous solution by the water droplets and the gas adheres to the inner wall surface of the gas flow path, stored in a mounting portion of the diaphragm portion can you to recover. It is possible to blow up the aqueous solution in which the liquid drops, which are generated by the gas flow that has passed through the constriction part and the flow velocity becomes high, due to excessive contact between the gas and the water droplets, to the gas-liquid separation part as the next step.

The solvent recovery device of the present invention includes a water spray unit that makes water droplets contact with a gas containing a water-soluble solvent having a boiling point higher than that of water, and a gas-liquid separation unit that cools the gas that has contacted the water droplets in the water spray unit. The water spray section includes a suction port that sucks the gas, a discharge port that discharges the gas in contact with the water droplets to the gas-liquid separation unit, and a gas flow that connects the suction port and the discharge port. A cross-sectional area of the gas flow path between the discharge port and the nozzle, between the nozzle that ejects the water droplets, and the suction port and the nozzle. and said diaphragm portion to reduce the cross-sectional area of the gas flow path between the nozzle and the suction port is provided than the diaphragm portion consists guide plate provided on the inner wall surface forming said gas flow path, wherein guide plates, to cover all around the inner wall surface connected at one end to the inner wall surface Attached, the other end is mounted inclined to the other end in the structure remote from the inner wall so as to be positioned upward from the end, the water spray portion is a straight pipe, upwardly from the bottom The suction port, the throttle unit, the nozzle, and the discharge port are arranged in order, and include a concentrator, the concentrator includes a cooling unit that performs heat exchange between the aqueous solution and the gas, and is cooled by the cooling unit The gas is sucked into the water spraying part through the suction port, and the aqueous solution recovered in the gas-liquid separation part is collected in the concentrator through a pipe and flows into the cooling part, Provided on the upper side of the concentrator, and provided with a return pipe connecting the constriction unit and the cooling unit of the concentrator to guide the aqueous solution accumulated in the constriction unit to the cooling unit, the concentrator Heat and concentrate aqueous solution by heat exchange of gas It is an aqueous solution caused by the water droplets and the gas adheres to the inner wall surface of the gas flow path, stored in a mounting portion of the diaphragm portion can you to recover. The aqueous solution can be prevented from flowing into the concentrator.

An embodiment of the present invention includes a water spray unit that makes water droplets contact with a gas containing a water-soluble solvent having a boiling point higher than that of water, and a gas-liquid separation unit that cools the gas that has contacted the water droplets in the water spray unit. The water spray section includes a suction port that sucks the gas, a discharge port that discharges the gas in contact with the water droplets to the gas-liquid separation unit, and a gas flow that connects the suction port and the discharge port. and a road, the cross-sectional area of the gas flow path between said the gas flow path, a nozzle for jetting the water droplet, between the nozzle and the suction port, the discharge port and the nozzle and said diaphragm portion to reduce the cross-sectional area of the gas flow path between the nozzle and the suction port is provided than the diaphragm portion, constituted by a guide plate provided on the inner wall surface forming said gas flow path, the guide plate is to cover all around the inner wall surface connected at one end to the inner wall surface Ri attached, the other end is mounted inclined to the other end in the structure remote from the inner wall so as to be positioned upward from the end, the water spray portion is a straight tube, from bottom to top direction The suction port, the throttle unit, the nozzle, and the discharge port are arranged in order, and include a concentrator, the concentrator includes a cooling unit that performs heat exchange between the aqueous solution and the gas, and is cooled by the cooling unit. The gas is sucked into the water spray section through the suction port, and the aqueous solution recovered by the gas-liquid separation section is collected in the concentrator through a pipe and flows into the cooling section, and the throttle section Is provided on the upper side of the concentrator, a return pipe is provided to connect the constriction unit and the cooling unit of the concentrator, and the aqueous solution accumulated in the constriction unit is guided to the cooling unit, it concentrated by heating the aqueous solution by the heat exchange of the gas It is intended to refer.

With this configuration, the resulting aqueous solution by the water droplets and the gas adheres to the inner wall surface of the gas flow path, stored in a mounting portion of the diaphragm portion can you to recover. Since the flow velocity of the gas flowing in the gas flow path can be accelerated, the gas that has increased in weight due to contact with the water droplets can be blown up to the vicinity of the discharge port. Since the gas in contact with the water droplets can be delivered from the water spraying part to the gas-liquid separation part, the amount of water-soluble solvent recovered as an aqueous solution in the gas-liquid separation part increases. The aqueous solution can be prevented from flowing into the concentrator.

  In the embodiment of the present invention, the throttle portion is provided on the suction port surface side of the guide plate with a mixed flow guide portion that changes the flow direction of the gas flowing from the suction port to the discharge port in an oblique direction. is there.

  By adopting this configuration, a diagonal flow of gas along the inner wall surface of the gas flow path can be generated in the space where the water droplets in the water spray section and the gas are in contact with each other.

  As a result, it is possible to suppress the gas that has contacted the water droplets from adhering to the inner wall surface of the gas flow path, and the amount of gas that can be supplied to the gas-liquid separation unit, which is the next process, is increased.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
FIG. 1 is a configuration diagram of a solvent recovery device for a water-soluble solvent in Example 1 of the present invention. The overall outline of the solvent recovery apparatus 100 will be described with reference to FIG.

  A solvent recovery apparatus 100 that recovers a water-soluble solvent cools the gas 1 and also heats and concentrates the aqueous solution 3 separated by the gas-liquid separation unit 40 described later, and is cooled by the concentrator 20. The water spray unit 30 that contacts the water droplet 2 with the gas 1a and the gas-liquid separation unit 40 that cools the gas 1b that has contacted the water droplet 2 with the water spray unit 30 are provided.

  The aqueous solution 3 containing the water-soluble solvent extracted by the gas-liquid separator 40 is guided to the concentrator 20 through the pipe 50. The aqueous solution 3 that has flowed into the concentrator 20 exchanges heat with the newly sucked gas 1, thereby evaporating the moisture in the aqueous solution 3 and increasing its concentration. As a result, the aqueous solution 3 a having a high concentration is collected in the tank 51 through the pipe 6. On the other hand, the gas 1c from which the aqueous solution component has been removed by the gas-liquid separator 40 is purified by the eliminator 52 and released into the atmosphere.

  Each part of such a solvent collection | recovery apparatus 100 is demonstrated with the flowchart which shows the solvent collection | recovery procedure of the water-soluble solvent in Example 1 of this invention shown in FIG. The water-soluble solvent will be described using NMP.

The gas 1 collected as exhaust gas from a factory or the like is cooled by the concentrator 20 (S1). As shown in FIG. 1, the concentrator 20 is divided into a cooling preparation chamber 21, a cooling unit 22, and a discharge preparation chamber 23. The gas 1 blown from the outside of the concentrator 20 into the cooling preparation chamber 21 by the fan 5 is sucked into a plurality of pipes 24 provided in the cooling unit 22. The cooling unit 22 is partitioned by a plurality of partition plates 25 and 26. Around the tube 24, an aqueous solution 3 described later is stored in the cooling section 22 partitioned by the plurality of partition plates 25 and 26, and exchanges heat with the gas 1. The gas 1a radiated and cooled by the cooling unit 22 is sent out to the water spraying unit 30 which is the next process through the discharge preparation chamber 23.

  As an example, when the gas 1 containing NMP sucked into the cooling preparation chamber 21 is around 100 ° C., and the aqueous solution 3 in the cooling preparation chamber 21 is around 25 ° C., the gas 1a present in the discharge preparation chamber 23 is 70 It is possible to cool to about 0C.

  Next, the gas 1 a is sucked into the water spray unit 30 through the suction port 31 that connects the concentrator 20 and the water spray unit 30.

  The water spray unit 30 includes a gas flow path 33 that connects the suction port 31 and the discharge port 32. In the first embodiment, a vertically long water spray unit 30 is used. Inside the gas flow path 33, the gas suction chamber 34 from the suction port 31 to the throttle part 35 and the gas liquid from the throttle part 35 to the discharge port 32 are bordered by a throttle part 35 that reduces the area of the flow path through which the gas 1 a flows. Separated from the contact chamber 37. A nozzle 36 is provided in the gas-liquid contact chamber 37. The water droplet 2 sprayed from the nozzle 36 comes into contact with the gas 1 a in the gas-liquid contact chamber 37.

  Hereinafter, the water spray unit 30 will be described in detail.

  First, the nozzle 36 is attached below the water spray unit 30 in order to collect as much of the aqueous solution 3 containing NMP as possible in the gas-liquid separation unit 40 as the next step. With this configuration, the gas 1 a and the water droplet 2 can sufficiently come into contact with each other in the gas-liquid contact chamber 37.

  The nozzle 36 is connected to a water supply pipe 36 a that supplies water that is a source of the water droplets 2 and an air supply pipe 36 b that supplies compressed air for ejecting water. The diameter of the water droplet 2 sprayed from the nozzle 36 is determined by the diameter of the hole applied to the nozzle 36. The spray speed and spray amount of the water droplet 2 can be adjusted by the pressure of the compressed air that ejects water. In the first embodiment, in order to bring more water droplets 2 into contact with NMP contained in the gas 1a, a nozzle 36 that can obtain water droplets 2 having a diameter of about 10 μm is used. In addition, since the surface area per unit volume will become large if the diameter of the water droplet 2 is made small, even if it is the same amount of water, it becomes possible to contact with more NMP (S2).

  Further, when the flow rate of the gas 1 flowing into the solvent recovery device 100 is not stable, the amounts of water and compressed air supplied from the water supply pipe 36a and the air supply pipe 36b are adjusted in accordance with the flow rate of the gas 1a flowing in the gas flow path 33. It may be possible to adjust. According to this configuration, the amount of water and compressed air can be adjusted according to the amount of NMP contained in the gas 1a and an appropriate amount of water droplets 2 can be supplied, so that unnecessary water and compressed air are not consumed.

  Next, in order to collect as much NMP as possible in the next step, it is necessary to send as much gas 1b in sufficient contact with the water droplets 2 in the gas-liquid contact chamber 37 to the gas-liquid separator 40 as much as possible.

  To meet this requirement, the following considerations are necessary.

  First, the direction of the water droplet 2 ejected from the nozzle 36 in the gas-liquid contact chamber 37 is defined as the direction of the discharge port 32 (upper side in the figure). That is, the water droplet 2 is sprayed in the same direction as the gas 1a so that the flow of the gas 1a is not hindered.

  Next, the speed of the water droplet 2 to be sprayed is made slower than the flow rate of the gas 1a. By doing so, the gas 1a passes through the water droplet 2 drifting in the gas-liquid contact chamber 37, so that the opportunity for the gas 1a to contact the water droplet 2 increases. That is, from the relationship between the relative speeds of the water droplet 2 and the gas 1a, the time during which the water droplet 2 and the gas 1a are in contact with each other can be increased as much as possible.

  Furthermore, the throttle part 35 which accelerates | stimulates the flow velocity of the gas 1a is provided so that the gas 1b which increased in weight by contacting with the water droplet 2 can move to the gas-liquid separation part 40 without stalling.

  That is, if the cross-sectional area B of the opening 35a of the throttle portion 35 through which the gas 1a passes is made smaller than the cross-sectional area A of the gas suction chamber 34, the flow velocity of the gas 1a passing through the opening 35a is increased. According to this configuration, the gas 1b that has been in contact with the water droplet 2 and that has been dropped into the water spray unit 30 without reaching the discharge port 32 has passed through the opening 35a and increased in flow rate. It is blown up to 1 a and reaches the discharge port 32.

  By the way, in the first embodiment, after the gas 1b increased in weight by being brought into contact with the water droplet 2 is blown up to a predetermined height, in order to further promote the contact between the water droplet 2 and the gas 1b, the gas suction chamber 34 and the gas The liquid contact chamber 37 has the same cross-sectional area A, and the flow velocity of the accelerated gas 1b is returned to the flow velocity before passing through the throttle portion 35.

  The flow rate may be adjusted in consideration of the optimum speed of the gas 1b flowing into the gas-liquid separator 40, which is the next step, the contact state between the water droplet 2 and the gas 1b, and the like.

  In the first embodiment, the diameter a of the gas suction chamber 34 and the gas-liquid contact chamber 37 is 1000 mm, and the diameter b of the opening 35 a provided in the throttle portion 35 is 400 mm. As a result, the flow velocity t = 2 m / sec of the gas 1a flowing through the gas suction chamber 34 could be accelerated to the flow velocity of the cooled gas passing through the opening 35a.

  Further, in the water spray unit 30 of the first embodiment, the water droplet 2 and the gas 1a are in contact with each other, and the following measures are taken in order to efficiently recover the aqueous solution generated on the side wall surface of the gas flow path 33. ing.

  That is, as shown in FIG. 1, the throttle portion 35 is attached so that the opening 35 a of the throttle portion 35 is higher than the connection portion between the throttle portion 35 and the gas flow path 33. With this configuration, the aqueous solution 4 can be stored in the connection portion between the throttle portion 35 and the gas flow path 33. Further, a return pipe 53 is provided between the vicinity of the connecting portion between the throttle 35 and the gas flow path 33 and the concentrator 20. If the connecting portion between the constricting part 35 and the gas flow path 33 is provided above the concentrator 20, the aqueous solution 4 accumulated in the constricting part 35 can be transferred to the cooling part 22 without requiring unnecessary equipment such as a pump. Can supply.

  Next, the gas-liquid separator 40 will be described.

  The gas 1b discharged to the gas-liquid separator 40 through the discharge port 32 is cooled by the condenser 41 provided in the gas-liquid separator 40, and the NMP dissolved in the gas 1b is extracted as the aqueous solution 3. To be recovered.

  In the first embodiment, the condenser 41 is divided into two stages, the gas 1b is cooled from a high temperature to an intermediate temperature using the former condenser 41a, and the gas 1b is cooled from the medium temperature to a low temperature using the latter condenser 41b. (S3).

  The condenser 41 shown in FIG. 1 includes cooling pipes 42a and 42b and heat radiation parts 43a and 43b.

  Each condenser 41a, 41b is filled with water as a refrigerant.

  First, the gas 1b that has flowed into the gas-liquid separation unit 40 is cooled to a temperature of about 50 to 65 ° C. by directly touching the air near the cooling tube 42 a and the cooling tube 42 a. The refrigerant water exchanged with the gas 1b is circulated to the heat radiating portion 43a, and after the absorbed heat is released into the atmosphere, it is supplied to the cooling pipe 42a again.

  On the other hand, a part of the gas 1b in contact with the cooling pipe 42a that has reached the dew point is extracted as an aqueous solution 3 containing NMP.

  Similarly, the gas 1b flowing to the vicinity of the cooling pipe 42b is directly brought into contact with the air in the vicinity of the cooling pipe 42b and the cooling pipe 42b, whereby the temperature of about 40 ° C. is cooled to about 20 ° C. Since the cooling pipe 42b has a lower temperature than the cooling pipe 42a, more gas 1b can be guided to the dew point, and the aqueous solution 3 containing more NMP than the cooling pipe 42a can be extracted and recovered.

  On the other hand, the coolant water exchanged with the gas 1b is circulated to the heat radiating portion 43b, and after the absorbed heat is released into the atmosphere, it is supplied to the cooling pipe 42b again.

  Next, the gas 1 c from which the three main components of the aqueous solution are removed by the gas-liquid separator 40 is further sent to the eliminator 52. The gas 1c passes through a net-like portion 52a made of a fine metal wire provided in the eliminator 52, whereby liquid fine particles that have not been removed by the gas-liquid separator 40 are separated and recovered (S4).

  Thereafter, the gas 1d separated into the liquid fine particles is released into the atmosphere.

  Further, the aqueous solution 3 containing NMP extracted and recovered by the gas-liquid separator 40 and the eliminator 52 is collected to the concentrator 20 via the pipe 50.

  By the way, the cooling unit 22 that has cooled the gas 1 by the concentrator 20 has a function of heating and concentrating the recovered aqueous solution 3 to recover the aqueous solution 3 having a high NMP concentration.

  First, the details of the cooling unit 22 provided in the concentrator 20 will be described. 3 shows an AA arrow view and a BB arrow view of FIG.

  As shown in FIG. 3A, the partition plate 26 has a shape in which the upper end is cut off, and as shown in FIG. 3B, the partition plate 25 has a shape in which the lower end is cut out, and the notch portions 25a and 26a are adjacent spaces. As a connecting route to That is, the cooling unit 22 includes a flow path for sending the aqueous solution 3 flowing into the cooling unit 22 through the pipe 50 from the cooling unit 22 to the tank 51.

  As described above, the gas 1 sucked into the cooling preparation chamber 21 at a high temperature of about 100 ° C. is lowered to about 70 ° C. until it reaches the discharge preparation chamber 23 to dissipate heat. In other words, heat of substantially the same capacity as that radiated heat is supplied to the cooling unit 22. This heat increases as the aqueous solution 3 flows from the right to the left in the cooling unit 22 because the gas 1 flows from the left to the right in the cooling unit 22. That is, the moisture contained in the aqueous solution 3 is evaporated by the heat supplied from the gas 1 (S5).

  In this way, the aqueous solution 3a containing NMP concentrated by evaporating moisture is collected in the tank 51. On the other hand, as a result of heat exchange with the gas 1, the vapor containing NMP evaporated from the aqueous solution 3 is led to the cooling preparation chamber 21 of the concentrator 20 through the return pipe 27.

  As described above, in the solvent recovery apparatus 100 according to the first embodiment of the present invention, the throttle unit 35 is provided inside the water spray unit 30 and flows from the suction port 31 of the water spray unit 30 to the discharge port 32. The cross-sectional area of the flow path of the gas 1a is narrowed by the main part. The throttling unit 35 may be appropriately designed according to the shape and size of the water spray unit 30 to be used or the component of the flowing gas 1a. However, it is necessary to pay attention to the following contents.

  The first is to ensure the contact time between the gas 1a and the water droplet 2 ejected from the nozzle 36, which is the main purpose of the water spray section 30, as long as possible. As described above, in the gas-liquid separation unit 40, which is the next step, it is necessary to attach sufficient water droplets 2 to the gas 1a in order to recover as much water-soluble solvent as possible contained in the gas 1a. . Specifically, when the water spray unit 30 shown in FIG. 1 is used, the throttle unit 35 and the nozzle 36 are installed below the water spray unit 30 to ensure a sufficient space from the nozzle 36 to the discharge port 32. This is realized.

  The second is to send the gas 1b in contact with the water droplet 2 to the gas-liquid separation unit 40, which is the next step, without liquefying in the water spray unit 30. In the solvent recovery apparatus 100 shown in the first embodiment, the NMP that has become the aqueous solution 3 is configured to be recovered from the gas-liquid separation unit 40, and the water spray unit 30 actively removes the NMP that has become the aqueous solution. It is not configured to collect. Therefore, when the gas 1b is liquefied in the water spray section 30, the NMP aqueous solution 3 that can be recovered by the gas-liquid separation section 40 is reduced. In addition, backflow from the discharge port 32 to the concentrator 20, which is the previous process, may occur, and when water droplets remain in the lower part of the water spray unit 30, it is necessary to frequently drain water to prevent internal corrosion. There will be an extra amount of trouble.

  Therefore, in order to send the gas 1 a to the gas-liquid separation unit 40, the throttle unit 35 and the nozzle 36 are provided above the water spray unit 30.

  In order to realize the first and second contradictory considerations, in the first embodiment of the present invention, the throttle part 35 and the nozzle 36 are installed at the lower part of the water spraying part 30, and the gas 1a, the water droplet 2 and The flow rate of the gas 1a is increased by restricting the cross-sectional area of the main part of the gas flow path 33 by using the opening 35a of the restricting part 35, thereby preventing droplets and allowing more gas 1b to escape. It is made to discharge to the liquid separation part 40.

  By setting it as such a structure, the water droplet 2 which has fallen in the water spray part 30 can be blown up to the water spray part 30 upper direction. Moreover, since the cross-sectional area of the gas flow path 33 at the upper part of the water spraying part 30 has an area capable of obtaining a speed at which the water droplet 2 and the gas 1b can sufficiently contact with each other, it is accelerated by the throttle part 35. Further, the flow rate of the gas 1a can be suppressed, and the contact between the water droplet 2 and the gas 1b can be promoted.

  In addition, when the aperture | diaphragm | squeeze part 35 shown in FIG. 1 is used, it can adhere to the side wall surface of the water spray part 30, and can receive the aqueous solution 4 which becomes unavoidable.

  With such a configuration, it is possible to prevent the aqueous solution 4 that is inevitably generated from flowing backward to the concentrator 20 that is the previous step.

  In addition, as shown in FIG. 1, if a return pipe 53 that connects the throttle unit 35 of the water spray unit 30 and the cooling unit 22 of the concentrator 20 is provided and the aqueous solution 4 is returned to the cooling unit 22, more It becomes possible to collect the aqueous solution 3a of NMP.

  If the throttling part 35 is installed above the concentrator 20, the aqueous solution 4 can be guided to the cooling part 22 via the return pipe 53 without installing extra equipment such as a pump.

( Reference Example 1 )
Next, Reference Example 1 will be described with reference to FIG.

  In FIG. 4, the tip of the throttle portion 38 is directed toward the suction port 31 in the water spray portion 30a. In the case of this configuration, the aqueous solution 4a inevitably generated as a result of contact between the water droplet 2 and the gas 1a in the upper part of the water spraying part 30a and adhering to the side wall surface of the water spraying part 30a is as follows. It can be recovered.

  That is, the aqueous solution 4a adhering to the side wall surface flows along the side wall surface to the throttle portion 38. The aqueous solution 4 a that has reached the throttle portion 38 flows to the opening 38 a of the throttle portion 38 according to the inclination of the throttle portion 38. As a result, when the aqueous solution 4 a reaches the opening 38 a of the throttle portion 38, the aqueous solution 4 a is blown up from the opening 38 a to the discharge port 32 by the gas 1 a flowing from the suction port 31 to the discharge port 32. In particular, since the opening 38a squeezes the cross-sectional area of the gas flow path 33 to accelerate the flow rate of the gas 1a, the flow rate is sufficient to blow up the aqueous solution 4a.

  Further, as shown in FIG. 5, an air guide plate 39 having a lower end connected to the inner wall surface of the water spray unit 30 a and an upper end opened near the opening 38 a of the throttle unit 38 is provided below the throttle unit 38. If such a wind guide plate 39 is provided, as shown by arrows 60a and 60b in the figure, the flow of a smooth wind that continues from the inner wall surface of the water spray portion 30a to the throttle portion 38 via the wind guide plate 39 is shown. Can be built.

  If such a smooth wind flow can be constructed, energy loss of the fan 5 or the like that moves the cooled gas 1a can be suppressed, and energy saving for driving the solvent recovery apparatus 100 can be achieved.

(Example 2 )
Next, a second embodiment of the present invention will be described with reference to FIGS. 6-8.

  6 and 7 show the diaphragm portions 70 and 71 in another embodiment. That is, as shown in FIG. 6, the mixed flow guide portion 73 is provided using the guide plate 72 of the restricting portion 70, or the mixed flow guide portion 75 is provided on the guide plate 74 of the restricting portion 71 as shown in FIG. .

  The throttle portions 70 and 71 having such mixed flow guide portions 73 and 75 are installed in the water spray portion 30b shown in FIG. In the cooled gas 1 a sucked from the suction port 31, a gas flow 76 a flowing through the central portion of the gas flow path 33 and a gas flow 76 b flowing along the side wall surface are generated. Since the gas flow 76a flowing through the central portion of the gas flow path 33 has a high flow velocity, it can be expected to smoothly flow to the discharge port 32 via the throttle portions 70 and 71.

  However, with respect to the gas flow 76b in the vicinity of the side wall surface, the smooth flow that flows from the suction port 31 to the throttle portions 70 and 71 and the discharge port 32 due to the influence of frictional force generated between the cooled gas 1a and the side wall surface. The flow of the gas 1a cannot be expected.

  Therefore, as shown in the third embodiment, by using the throttle portions 70 and 71 having the mixed flow guide portions 73 and 75, in the gas-liquid contact chamber 37, an oblique gas flow 77 along the inner wall surface, so-called A mixed flow can be generated. As a result, it is possible to promote the gas flow 77 in the vicinity of the inner wall surface and to prevent the gas 1b in contact with the water droplet 2 from adhering to the inner wall surface and liquefying.

  Accordingly, the amount of the gas 1b that can be recovered by the gas-liquid separator 40, which is the next step, is increased, and the recovery efficiency of the aqueous solution 3 in which NMP is dissolved can be improved.

  The solvent recovery device of the present invention is useful in the field of continuous exhaust gas purification because a low-concentration water-soluble solvent in exhaust gas can be recovered stably and efficiently without using an adsorbent.

Configuration diagram of solvent recovery apparatus in one embodiment of the present invention The flowchart which shows the solvent recovery procedure of the water-soluble solvent in one Example of the same invention (A) is the AA arrow directional view of the cooling unit 22 in one Example of this invention, (b) is the BB arrow directional view. Configuration diagram of water spray section in reference example Configuration diagram of water spray section in other reference examples The perspective view of the aperture | diaphragm | squeeze part in other one Example of this invention. The perspective view of the aperture | diaphragm | squeeze part in other one Example of this invention. The block diagram of the water spray part in other one Example of this invention

Explanation of symbols

1, 1a, 1b, 1c, 1d Gas 2 Water droplet 20 Concentrator 30, 30a, 30b Water spraying portion 31 Suction port 32 Discharge port 33 Gas flow path 35, 38, 70, 71 Restriction portion 36 Nozzle 39 Air guide plate 40 Air Liquid separation part 72, 74 Guide plate 73, 75 Diagonal flow guide part

Claims (2)

A water spray section for bringing water droplets into contact with a gas containing a water-soluble solvent having a boiling point higher than that of water;
A gas-liquid separation unit that cools the gas in contact with the water droplets in the water spray unit;
The water spray section is
A suction port for sucking the gas;
A discharge port for discharging the gas in contact with the water droplets to the gas-liquid separator;
A gas flow path connecting the suction port and the discharge port;
In the gas flow path,
A nozzle that ejects the water droplets;
The cross-sectional area of the gas flow path between the suction port and the nozzle is smaller than the cross-sectional area of the gas flow path between the discharge port and the nozzle between the suction port and the nozzle. With a diaphragm,
The throttle part is
A guide plate provided on the inner wall surface forming the gas flow path,
The guide plate is attached so that one end thereof is connected to the inner wall surface and covers the entire inner wall surface, and the other end is inclined so that the other end is located above the one end with a structure separated from the inner wall. Attached ,
The water spray part is a straight pipe, and from the bottom to the top, the suction port, the throttle unit, the nozzle, the discharge port are arranged in this order,
With a concentrator,
The concentrator includes a cooling unit that performs heat exchange between the aqueous solution and the gas,
The gas cooled by the cooling unit is sucked into the water spray unit through the suction port,
The aqueous solution recovered in the gas-liquid separation unit is collected in the concentrator through a pipe and flows into the cooling unit,
The throttle part is provided above the concentrator,
Providing a return pipe connecting the constriction section and the cooling section of the concentrator to guide the aqueous solution accumulated in the constriction section to the cooling section;
The concentrator is a solvent recovery apparatus that heats and concentrates an aqueous solution by heat exchange between the aqueous solution and the gas . Further, the aperture portion is
The solvent recovery apparatus according to claim 1, wherein a mixed flow guide portion that changes a flow direction of the gas flowing from the suction port to the discharge port is provided on the suction port surface side of the guide plate.

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