JP6937016B2 - Spray dryer - Google Patents

Description

The present invention relates to a spray drying device, and more particularly to a spray drying device suitable for pulverizing a sample solution.

Conventionally, in a spray drying device, a sample solution is sprayed into an evaporation tower into which high-temperature hot air is introduced and dried by a two-fluid spray nozzle or a rotary atomizer, and the generated solid particles are collected by a cyclone. (See, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2004-92969 Japanese Unexamined Patent Publication No. 2016-155055

In recent years, in the field of drug discovery development research, nanoparticle crystals having an excellent dissolution rate have been attracting attention, and in particular, the development of a spray drying device capable of producing nanoparticle crystals such as heat-sensitive proteins has been desired. There is. However, as in Patent Documents 1 and 2 described above, the particle size of solid particles that can be produced by a spray drying device using a two-fluid spray nozzle or a rotary atomizer is about 10 to 50 μm, and the collection rate is also about 70%. At rest. In addition, since particles that can be collected by a cyclone require a certain mass and particle size, it is difficult to collect nanoparticle crystals. Further, the evaporated solvent may be adsorbed on the collected particles to reduce the degree of dryness, and the particles may adhere to each other to increase the particle size.

Therefore, an object of the present invention is to provide a spray drying device capable of efficiently pulverizing a sample solution into fine powder and collecting the sample solution.

In order to achieve the above object, the spray dryer of the present invention uses a sprayer that sprays a sample solution in which a solute to be recovered as a powder is dissolved in a solvent, and a atomized sample solution sprayed from the sprayer to heat the solvent. An evaporative tube that evaporates to generate fine solute powder, a hot air supply device that supplies hot air into the evaporative tube, and a powder collector that collects fine powder in the fine powder-containing gas derived from the evaporative tube. In a spray drying device provided with an exhaust means for discharging gas after separating fine powder by the powder collector, the evaporation tube is a mist-like sample sprayed from the atomizer on the upper part of the evaporation tube. It has a mixing part that mixes the solution and the hot air supplied from the hot air supply device, and contains fine powder at the bottom of the evaporation tube to derive the fine powder-containing gas from the evaporation tube toward the powder collector. It is characterized in that a gas outlet is provided and a solvent vapor trapping means for condensing the solvent of the sample solution evaporated in the evaporation tube is provided. Further, the evaporation tube is made of transparent glass.

Further, the spray drying device of the present invention includes a atomized sample solution guide tube in which the atomizer guides the atomized sample solution sprayed downward toward the upper part of the evaporation tube. A large-diameter tube portion that covers the lower outer periphery of the atomized sample solution guide tube, a small-diameter tube portion provided below the large-diameter tube portion, a lower end of the large-diameter tube portion, and the above. A tapered tube portion that connects the upper end of the small diameter tube portion is provided, and hot air from the hot air supply device is supplied between the inner peripheral surface of the large diameter tube portion and the lower outer peripheral surface of the atomized sample solution guide tube. A hot air supply pipe that forms a hot air passage and supplies hot air from the hot air supply device is provided in the hot air passage in a tangential direction with respect to the outer peripheral surface of the large diameter pipe portion, and the atomized sample solution guide pipe. A ring-shaped hot air passing portion is formed between the lower end of the pipe portion and the inner peripheral surface of the tapered pipe portion to allow hot air in the hot air passage to pass toward the mixing portion. Further, a heat insulating cover made of a transparent material is provided on the outer periphery of the small diameter tube portion, and the atomizer does not transfer heat from the hot air passage at the upper end portion of the mist-like sample solution guide tube. It is characterized by being provided at a position.

The powder collector includes a bottomed tubular collector body, a collector lid detachably provided in the upper opening of the collector body, and a collector body and a collector lid. A fine powder collection filter having an outer peripheral portion sandwiched between the two, an exhaust port provided on the collector lid to which the exhaust pipe of the exhaust means is connected, and a fine powder-containing gas outlet of the evaporation pipe. The fine powder-containing gas conduit for introducing the fine powder-containing gas derived from the above into the collector main body is provided, and the fine powder-containing gas conduit is provided in a tangential direction with respect to the peripheral wall of the collector main body. It is characterized by that.

According to the spray drying device of the present invention, since the solvent vapor trapping means for condensing the solvent vapor is provided at the lower part of the evaporation tube, the amount of the solvent vapor toward the powder collector can be significantly reduced, and the quality is high. Fine powder can be obtained. Further, since the atomizer is provided on the upper part of the evaporation tube via the mist sample solution guide tube, the hot air supplied into the evaporation tube and the mist sample solution can be effectively mixed, and the mist sample can be mixed. The solution can be heated quickly to evaporate the solvent instantly. In addition, by forming the evaporation tube with transparent glass, the state inside the evaporation tube can be easily confirmed from the outside, and by covering the outer circumference with a heat insulating cover, it is possible to prevent the temperature of the small-diameter tube through which the solvent vapor flows from dropping. It is possible to prevent the solvent vapor from condensing on the inner peripheral surface. Further, by spraying the atomized sample solution finely divided by the operation of the ultrasonic horn toward the evaporation tube via the micromesh, the sample solution can be made into a fine atomized state, and the particle size is 0. A fine powder of 1 to 3 μm can be produced.

It is a partial cross-sectional front view of the spray drying apparatus which shows one embodiment of this invention. Similarly, it is a partial cross-sectional side view of the spray drying device. It is also a cross-sectional view of the atomizer. It is also a cross-sectional view of a powder collector. Similarly, it is a perspective view of a fine powder collection filter. It is sectional drawing which shows the other form example of the powder collector used in the spray drying apparatus of this invention. Similarly, it is a perspective view of a fine powder collection filter.

1 to 5 are views showing an example of one embodiment of the spray drying device of the present invention. The spray drying device 11 of this embodiment is a solution supply device 12 such as a tube pump that sucks and supplies the sample solution in the sample container 12a, a sprayer 13 that sprays the supplied sample solution, and a sprayed atomized form. An evaporation tube 14 for evaporating the solvent of the sample solution, a hot air supply device 15 for supplying hot air obtained by heating air with an electric heater to the evaporation tube 14, and fine powder in a fine powder-containing gas derived from the lower part of the evaporation tube 14. A powder collector 16 for collecting the gas and an exhaust means 17 such as a diaphragm pump or a dry vacuum pump for discharging the gas after the fine powder is separated by the powder collector 16 are provided.

As shown in FIG. 3, the atomizer 13 stores a housing 13a provided with an ultrasonic transducer, an ultrasonic horn 13b of an ultrasonic transducer protruding downward from the housing 13a, and a sample for storing a certain amount of a sample solution. The pot 13c and the sample solution provided on the bottom surface of the sample pot 13c are held in the sample pot 13c, and the atomized sample solution atomized by the operation of the ultrasonic horn 13b is permeated and sprayed downward. The micromesh 13d is connected to the solution supply device 12 via a solution introduction tube (not shown), and the solution introduction nozzle 13e for introducing the sample solution into the sample pot 13c and the solution return to the solution supply device 12. The return nozzle 13f, which is connected via a tube (not shown) and returns the excess sample solution in the sample pot 13c, and the atomized sample solution that has passed through the micromesh 13d are guided toward the lower evaporation tube 14. It is provided with a mist-like sample solution guide tube (13 g). As the micromesh 13d, an appropriate one can be used as long as the sample solution can be held on the upper surface and the atomized sample solution can be permeated, but usually, a mesh size of 3 to 5 μm is used depending on conditions such as the type of sample solution. It may be selected as appropriate.

The evaporation pipe 14 attached to the housing 19 of the control device by the upper support member 18a and the lower support member 18b includes a large-diameter pipe portion 14a covering the lower outer periphery of the atomized sample solution guide pipe 13g and the large-diameter pipe. A bottomed small-diameter pipe portion 14b provided below the portion 14a, a tapered pipe portion 14c having a reduced diameter below connecting the lower end of the large-diameter pipe portion 14a and the upper end of the small-diameter pipe portion 14b, and a large-diameter pipe portion. It has a hot air passage 14d formed between the inner peripheral surface of 14a and the outer peripheral surface of the atomized sample solution guide tube 13g.

The large-diameter pipe portion 14a is provided with a hot air introduction port 14e for introducing hot air supplied from the hot air supply device 15 via the hot air supply pipe 15a into the hot air passage 14d. The hot air supply pipe 15a is provided in a tangential direction with respect to the outer peripheral surface of the large diameter pipe portion 14a, and the hot air flowing into the hot air passage 14d from the hot air introduction port 14e forms a swirling flow in the hot air passage 14d. It is made to flow downward in a spiral shape.

As the hot air supply device 15, it is possible to use an electric heater that heats the air sucked by the suction force of the exhaust means 17 to a preset temperature, but it is also possible to use nitrogen gas or the like, and an electric heater. It is also possible to use a heating means other than the above.

A fine powder-containing gas outlet 14f is provided on the lower side surface of the small-diameter pipe portion 14b, and a cooling coil 14g as a solvent vapor trapping means is provided in the small-diameter pipe portion 14b below the fine powder-containing gas outlet 14f. Is provided, and a drainage portion 14h is provided at the bottom of the small-diameter pipe portion 14b.

A fluid having a temperature at which the solvent vapor can be condensed may be passed through the cooling coil 14 g. For example, when the solvent vapor is steam, chiller water cooled to about 2 ° C. can be used, and a dehumidifying agent should be used. Is also possible. Further, the solvent vapor may be condensed by cooling the bottom portion of the small diameter tube portion 14b, and a plurality of solvent vapor trapping means can be used in combination.

Further, a ring-shaped hot air passing portion 14i is formed between the lower end of the mist-like sample solution guide tube 13g and the inner peripheral surface of the tapered tube portion 14c, and the hot air spirally flowing through the hot air passage 14d is generated. A mixing portion 14j is formed in which the atomized sample solution flowing along the inner peripheral surface of the small diameter tube portion 14b while maintaining the spiral flow and flowing out from the lower end of the atomized sample solution guide tube 13g and the hot air are mixed.

The atomized sample solution guide tube 13 g, the large-diameter tube portion 14a, the tapered tube portion 14c, and the small-diameter tube portion 14b are appropriately divided and formed in consideration of moldability, cleanability, and the like. A fine powder-containing gas in which the upper part of the sample solution guide tube 13 g, the large-diameter tube portion 14a, the tapered tube portion 14c, and the small-diameter tube portion 14b is integrally formed, and is connected to the lower part of the small-diameter tube portion 14b and the fine powder-containing gas outlet 14f. The base end portion of the conduit 20 is integrally formed. The small diameter pipe portion 14b is divided into three parts, an upper part, an intermediate part, and a lower part, and the connecting flanges provided in the divided parts are tightly connected by clamps 21 and 21 so as to be airtightly and disassembled. Further, a heat insulating cover 22 having sealing materials 22a at both upper and lower ends is provided on the outer periphery of the intermediate portion of the small diameter pipe portion 14b so that the temperature of the small diameter pipe portion 14b does not decrease.

The powder collector 16 includes a bottomed tubular collector main body 16a, a collector lid 16b that is detachably attached to the upper opening of the collector main body 16a by a clamp 23, and a collector main body. The fine powder-containing gas introduction port 16c provided on the side wall of 16a, the fine powder collection filter 24 provided in the collector main body 16a, and the exhaust means 17 provided on the collector lid 16b. It is provided with an exhaust port 16d to which the pipe 17a is connected.

The fine powder-containing gas inlet 16c is connected to the fine powder-containing gas outlet 14f of the evaporation pipe 14 via a fine powder-containing gas conduit 20 having a free coupling in the middle, and the fine powder-containing gas conduit 20 is connected. , It is arranged in the tangential direction with respect to the outer peripheral surface of the collector main body 16a. As a result, the fine powder-containing gas flowing into the collector main body 16a from the fine powder-containing gas introduction port 16c is introduced along the inner peripheral surface of the collector main body 16a, and a swirling flow is generated in the collector main body 16a. I try to form it.

The fine powder collection filter 24 is formed in a hat shape having a filter main body portion 24a formed in a bottomed cylindrical shape and a flange portion 24b provided on the outer periphery of the upper opening of the filter main body portion 24a. The outer peripheral portion of the portion 24b is sandwiched between the opening flange 16e of the collector main body 16a and the collector lid 16b and held in the collector main body 16a. Further, in the collector lid 16b, a net body 16f using a stainless steel net-like body for holding filters of various shapes is fitted while preventing foreign matter from being sucked into the exhaust means 17. It has been. As the filter in the filter main body 24a, an appropriate filter can be used depending on conditions such as the particle size and amount of the fine powder to be collected. For example, when the amount of the fine powder collected is relatively large, the surface may be used. It may be formed in a hat shape by using a tubular membrane filter made of a plastic non-woven fabric covered with a resin fiber.

On the other hand, when the amount of fine powder collected is relatively small, as shown in FIGS. 6 and 7, a filter 25 formed in a disk shape having substantially the same diameter as the opening flange 16e of the powder collector main body 16a is used. can do. The disk-shaped filter 25 is arranged in the powder collector main body 16a with the outer peripheral portion sandwiched between the powder collector main body 16a and the lid member 16b in a state of being overlapped on the lower surface of the net body 16f. .. The material of the disk-shaped filter 25 is arbitrary, but for example, a tetralatex membrane can be preferably used.

In the spray drying device 11 formed in this way, the gas flowing portions such as the atomized sample solution guide tube 13 g, the evaporation tube 14, the fine powder-containing gas conduit 20, and the filter main body 24a are each formed of transparent glass, and further. By forming the heat insulating cover 22 with a transparent synthetic resin, the internal state can be easily observed from the outside, and an abnormal situation can be quickly dealt with.

Next, a method of using the spray drying device 11 having the configuration shown in FIG. 1 will be described. First, the exhaust means 17 is operated to form a gas (air) flow in the system, and the hot air supply device 15 is operated to heat the air to 100 ° C. or higher, and the cooling fluid is circulated through the cooling coil 14 g. When the temperature in the system becomes sufficiently high, the solution supply device 12 is operated to supply the sample solution in the sample container 12a into the sample pot 13c, and the excess sample solution is sucked and returned from the return nozzle 13f. Then, a certain amount of the sample solution is held in the sample pot 13c.

Then, the ultrasonic horn 13b of the ultrasonic vibrator is operated to make the sample solution into a atomized sample solution of fine particles via the micromesh 13d, and the sample solution is allowed to flow down into the atomized sample solution guide tube 13 g. On the other hand, the hot air generated by the hot air supply device 15 flows into the hot air passage 14d as a swirling flow from the hot air supply pipe 15a. When this hot air passes through the hot air passing portion 14i and flows from the tapered tube portion 14c toward the small diameter tube portion 14b, the mist sample solution flows out from the lower end of the mist sample solution guide tube 13g in the mixing section 14j. It merges and heats the mist sample solution to instantly evaporate the solvent, turning the solute into a fine powder. At this time, since the hot air is a swirling flow, the hot air and the mist-like sample solution come into contact with each other efficiently, the mist-like sample solution can be heated evenly, and the solvent is rapidly evaporated to produce fine solute powder. It can be generated efficiently.

Further, since only the lower outer periphery of the mist-like sample solution guide tube 13g is covered with the large-diameter tube portion 14a, the upper half of the mist-like sample solution guide tube 13g is heated by the hot air in the hot air passage 14d. The atomizer 13 provided at the upper end of the mist-like sample solution guide tube 13 g is not affected by heat, and there is no problem such as clogging as when the atomizer is installed at a high temperature. A mist-like sample solution can be produced in a stable state for a long period of time.

Further, since the hot air swirls along the inner peripheral surface of the tapered pipe portion 14c and the small diameter pipe portion 14b, it is possible to prevent the generated fine powder from adhering to the inner peripheral surface of the tapered pipe portion 14c and the small diameter pipe portion 14b. The entire fine powder can be smoothly flowed downward toward the small diameter tube portion 14b. Further, since the heat insulating cover 22 is provided on the outer periphery of the small diameter tube portion 14b, it is possible to suppress a decrease in the temperature inside the peripheral wall and the tube of the small diameter tube portion 14b, and the evaporated solvent is condensed on the peripheral wall of the small diameter tube portion 14b. As a result, the fine powder does not redissolve, and the inside can be reliably observed.

Most of the fine powder-containing gas flowing down the small-diameter pipe portion 14b flows into the powder collector 16 through the fine powder-containing gas conduit 20. The inflowing fine powder-containing gas spirally flows through the collector body 16a, and only the gas passes through the fine powder collection filter 24, is sucked into the exhaust means 17 from the exhaust port 16d, and is discharged to the outside of the system. ..

As a result, the fine powder is collected on the outer peripheral surface of the fine powder collection filter 24. At this time, since the fine powder-containing gas forms a swirling flow in the collector main body 16a, the fine powder can be efficiently collected all around the filter main body 24a, and the fine powder can be efficiently collected in the entire circumference of the filter main body 16a. It is possible to prevent fine powder from adhering to the inner peripheral surface.

On the other hand, a part of the fine powder-containing gas flowing down the small-diameter pipe portion 14b comes into contact with the cooling coil 14g at the lower part of the small-diameter pipe portion 14b, so that most of the large amount of solvent component contained in the fine powder-containing gas is removed. It condenses and separates from the fine powder-containing gas. The condensed liquid falls and is stored at the bottom of the small-diameter pipe portion 14b, and is discharged from the drainage portion 14h to the outside of the system by opening the opening / closing plug after the experiment is completed. As a result, the amount of solvent vapor contained in the fine powder-containing gas directed toward the fine powder collection filter 24 can be reduced, and the adsorption of solvent vapor to the fine powder collected by the fine powder collection filter 24 can be suppressed. A fine powder having a good degree of dryness can be obtained, the volume of the fine powder-containing gas can be reduced, and the load on the fine powder collecting filter 24 and the exhaust means 17 can be reduced.

Further, when an experiment was conducted in which 25 g of a 1% salt aqueous solution was used as a sample solution in the spray drying device 11 to collect fine powder of salt, the dry state was good and the particle size was 0.1 to 3 μm. 0.237 g of salt powder (recovery rate 95%) could be obtained.

In the spray drying device 11 of this embodiment, a cooling coil 14 g for condensing and separating the solvent vapor is provided below the fine powder-containing gas outlet 14f in the evaporation tube 14, and is generated when the solute fine powder particles are generated. By removing the solvent vapor, the contact between the fine powder collected by the fine powder collection filter 24 and the steam can be suppressed, and a fine powder having a good degree of dryness can be obtained.

Further, the sample solution is sprayed into a mist of fine particles through the micromesh 13d by the operation of the ultrasonic horn 13b, and the hot air is introduced as a swirling flow to effectively mix the hot air and the mist sample solution. The solvent in the atomized sample solution can be rapidly evaporated, and the solute in the sample solution can be efficiently obtained as a fine powder.

Further, by providing the heat insulating cover 22 on the outer periphery of the intermediate portion of the small-diameter tube portion 14b where the solvent evaporates, it is possible to prevent the temperature drop in the small-diameter tube portion 14b and improve the evaporation efficiency of the solvent, and the small-diameter tube portion. It is possible to prevent the temperature of the pipe wall of 14b from dropping and the formation of dew condensation on the inner surface. Then, by forming the evaporation pipe 14 and the powder collector 16 with transparent glass, the internal state of these can be easily visually recognized from the outside.

The spray-drying apparatus of the present invention is most suitable for an experiment in which fine powder is recovered from a small amount of sample solution. It is also possible to target a large amount of sample solution by appropriately setting according to the amount and the amount of fine powder collected.

11 ... Spray drying device, 12 ... Solution supply device, 12a ... Sample container, 13 ... Sprayer, 13a ... Housing, 13b ... Ultrasonic horn, 13c ... Sample pot, 13d ... Micromesh, 13e ... Solution introduction nozzle, 13f ... Return Nozzle, 13g ... Atomized sample solution guide tube, 14 ... Evaporation tube, 14a ... Large diameter tube, 14b ... Small diameter tube, 14c ... Tapered tube, 14d ... Hot air passage, 14e ... Hot air inlet, 14f ... Fine powder Containing gas outlet, 14 g ... Cooling coil, 14h ... Drainage part, 14i ... Hot air passage part, 14j ... Mixing part, 15 ... Hot air supply device, 15a ... Hot air supply pipe, 16 ... Powder collector, 16a ... Collection Vessel body, 16b ... Collector lid, 16c ... Fine powder-containing gas inlet, 16d ... Exhaust port, 16e ... Open flange, 16f ... Net body, 17 ... Exhaust means, 17a ... Exhaust pipe, 18a ... Upper support member , 18b ... Lower support member, 19 ... Housing, 20 ... Fine powder containing gas conduit, 21 ... Clamp, 22 ... Heat insulation cover, 22a ... Sealing material, 23 ... Clamp, 24 ... Fine powder collection filter, 24a ... Filter body Part, 24b ... Flange part, 25 ... Filter

Claims (6)

A sprayer that sprays a sample solution in which the solute to be recovered as a powder is dissolved in a solvent, an evaporation tube that heats the atomized sample solution sprayed from the sprayer to evaporate the solvent, and produces fine powder of the solute. A hot air supply device that supplies hot air into the evaporation tube, a powder collector that collects fine powder in the fine powder-containing gas derived from the evaporation tube, and a gas after separating the fine powder with the powder collector. In a spray drying device provided with an exhaust means for discharging the above, the evaporative tube mixes the atomized sample solution sprayed from the atomizer and the hot air supplied from the hot air supply device on the upper part of the evaporative tube. The sample having a mixing portion and having a fine powder-containing gas outlet for drawing out the fine powder-containing gas from the evaporation tube toward the powder collector at the bottom of the evaporation tube, and evaporating in the evaporation tube. A spray drying device provided with a solvent vapor trapping means for condensing a solvent of a solution. The spray drying device according to claim 1, wherein the evaporation tube is made of transparent glass. The atomizer includes a mist-like sample solution guide tube that guides the atomized sample solution sprayed downward toward the upper part of the evaporative tube, and the evaporative tube is provided on the upper part of the evaporative tube. A taper that connects a large-diameter tube portion that covers the lower outer periphery of the sample solution guide tube, a small-diameter tube portion provided below the large-diameter tube portion, and a lower end of the large-diameter tube portion and an upper end of the small-diameter tube portion. A hot air passage for supplying hot air from the hot air supply device is formed between the inner peripheral surface of the large-diameter pipe portion and the lower outer peripheral surface of the atomized sample solution guide tube, and the inside of the hot air passage is provided. A hot air supply pipe for supplying hot air from the hot air supply device is provided in a tangential direction with respect to the outer peripheral surface of the large diameter pipe portion, and the lower end of the mist-like sample solution guide pipe and the inner circumference of the tapered pipe portion. The spray drying device according to claim 1 or 2, wherein a ring-shaped hot air passing portion for passing hot air in the hot air passage toward the mixing portion is formed between the surface and the surface. The spray drying device according to claim 3, wherein a heat insulating cover made of a transparent material is provided on the outer periphery of the small diameter tube portion. The spray drying device according to claim 3 or 4, wherein the sprayer is provided at an upper end of the mist-like sample solution guide tube at a position where heat from the hot air passage is not transmitted. The powder collector includes a bottomed tubular collector body, a collector lid detachably provided in the upper opening of the collector body, and a collector body and a collector lid. A fine powder collection filter having an outer peripheral portion sandwiched between the two, an exhaust port provided on the collector lid to which the exhaust pipe of the exhaust means is connected, and a fine powder-containing gas outlet of the evaporation pipe. The fine powder-containing gas conduit for introducing the fine powder-containing gas derived from the above into the collector main body is provided, and the fine powder-containing gas conduit is provided in a tangential direction with respect to the peripheral wall of the collector main body. The spray drying apparatus according to any one of claims 1 to 5, characterized in that.

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