TECHNICAL FIELD

The present invention relates to an improvement of a microreactor, especially to an improvement of a microreactor employing a circular flow path formed between processing surfaces which rotate relative to each other, the circular flow path being used as the flow path in which fluid processing is carried out in the microreactor.

BACKGROUND ART

A microreactor is an apparatus in which a chemical reaction, a stirring operation, or the like is carried out in the space of 1 mm or less in each side, wherein many of them use a microchannel. Since about 20 years ago, this has been researched and developed in the field of a microprocess engineering; and recently, this is used also as an actual production apparatus. The microreactor is not a so-called batch-type reaction apparatus using a large tank or the like, but it is a continuous-type reaction apparatus, which is superior in an energy efficiency, a reaction rate, a yield, a safety, and the like to the batch-type apparatus in which a reaction is carried out in a larger scale (Patent Document 1).

However, because scaling-up of the microreactor is difficult, this is used in actual production with a numbering-up method, namely, by connecting small-type microreactors as many as necessary. However, because generally the microreactor uses a microchannel, the use thereof is difficult in a reaction accompanied with separation of solid or generation of a gas, a fluid processing to a highly viscous substance to be processed, and the like; and thus, there is a problem that the choice of the substance to be processed is limited (Patent Documents 2 and 3).

In order to solve these problems, recently the apparatus as described in Patent Document 4 has been frequently used. This is the apparatus provided with at least two processing surfaces which rotate relative to each other, wherein the two processing surfaces are disposed so as to be able to approach to or separate from each other in the axial direction of the rotation. The clearance between the two processing surfaces is kept very narrow, and at least two fluids to be processed are introduced into this very narrow clearance that is kept between the two processing surfaces thereby forming a forced thin film; and by mixing, stirring, or carrying out a reaction in this forced thin film, not only this apparatus can be used even in a reaction accompanied with solid separation, gas generation, or the like, or in processing of a highly viscous substance to be processed, but also a targeted uniform substance can be obtained.

This apparatus is characterized by that the fluid to be processed that is applied with a pressure by a fluid pressure imparting mechanism is made to pass through a circular flow path formed between the processing surfaces which are disposed in a position they are faced with each other so that the fluid to be processed is processed under the state of the thin film fluid having the thickness of, for example, 1 mm or less.

This apparatus may be used in a fluid processing method in which one fluid is passed as the fluid to be processed from inside to outside the circular flow path thereby forming the thin film fluid by one fluid so as to carry out the processing, as well as in a fluid processing method in which the thin film fluid is formed by plural fluids so as to carry out the processing. In the case where plural fluids (for example, a first fluid and a second fluid) are used, the first fluid is passed from inside to outside the circular flow path to form the thin fil fluid by the first fluid, and the second fluid is fed from the midway of the circular flow path so as to join the second fluid to the thin film fluid by the first fluid, whereby the processing is carried out under the state of the thin film fluid by the two fluids as the fluids to be processed. At this time, it is considered advantageous to join the first fluid to the second fluid under a laminar flow condition in order to realize homogeneous mixing by molecular diffusion in the thin film fluid.

In the fluid processing process using the fluid processing apparatus of Patent Document 4, the fluids to be processed are processed in the thin film fluid; and thus, the property of the fluids to be processed has a large effect to the result of the fluid processing. More specifically, the dissolution state and dispersion state of the fluids to be processed, i.e., the first fluid, the second fluid, and so forth, can have a large effect thereto, so that it is important to introduce the fluids to be processed into between the processing surfaces under the state that the fluids to be processed are homogeneously dissolved or dispersed in a molecular level or in a cluster level.

In addition, the temperature condition of the fluids to be processed is one factor to determine the reaction condition in the thin film fluid; and thus, it is important to introduce the fluids to be processed into between the processing surfaces under the state of the prescribed temperature thereof.

Therefore, in Patent Document 5, it is proposed that homogeneous microparticles can be separated from the fluid to be processed by controlling the dissolution state or the dispersion state of the first and second fluids by using ultrasonic waves or a high-speed stirrer.

However, it is difficult to control precisely two conditions, the dissolution and dispersion condition and the temperature condition, of the fluids to be processed which are immediately before being introduced into between the processing surfaces.

In the case where the microreactor described in Patent Documents 4 and 5 is used, it is a general practice that after raw materials of the fluids to be processed such as the first fluid, the second fluid, and so forth are mixed or dissolved, they are sent to inside the microreactor apparatus via a first heat-exchanger, a second heat-exchanger, and so forth in order to adjust the temperature conditions thereof; and then, they are introduced into between the processing surfaces via the respective flow paths that are arranged in the apparatus.

As a result of it, at the time of dissolving the raw material, even if the fluid to be processed is prepared in an ideal state by using the ultrasonic waves or a high-speed stirrer, the fluid to be processed after being prepared passes via a heat-exchanger, so that at the time when it arrives at the circular flow path in which the reaction takes place, there is a case that separation or heterogenisation of the raw material takes place. In this case, there has been a problem that the raw material cannot be introduced into between the processing surfaces due to clogging of the path, or that this causes the state that the thin film fluid is unstable.

In addition, when a water-soluble polymer or the like is used in the first fluid or the second fluid, there is a case that use of ultrasonic waves or the high-speed stirrer is not suitable because this causes decrease in the molecular weight of the polymer or inclusion of fine air bubbles thereinto.

On the other hand, the fluid processing apparatus described in Patent Document 6 and Patent Document 7, which is the divisional application of Patent Document 6, has been known, wherein a large shear force is applied to the fluid to be processed so as to mix and disperse the fluid by means of the shear force thereby applied. The apparatus described in Patent Documents 6 and 7 also carries out the fluid processing between the two processing surfaces which rotate relative to each other, similarly to the fluid processing apparatus described in Patent Document 4; but the basic technological concepts are totally different between these two.

Specifically, in the fluid processing apparatus described in Patent Documents 6 and 7, the fluid to be processed is mixed, emulsified, and dispersed by applying a large shear force to the fluid to be processed, the shear force being generated by rotating the two processing surfaces relative to each other. This apparatus can also be used for production of microparticles. In this apparatus, a large physical energy generated by high-speed rotation, for example, at about 8000 rpm to about 12000 rpm, is applied to particles in the fluid to be processed so as to micronize the particles to obtain the microparticles thereof. Therefore, the fluid processing apparatus described in Patent Documents 6 and 7 does not presuppose a chemical reaction, so that this is not the apparatus to be used as a microreactor.

On the contrary, in the fluid processing apparatus described in Patent Documents 4 and 5, the fluid to be processed passing through the circular flow path formed between the two processing surfaces which rotate relative to the other in a comparatively low speed, for example, at about 200 rpm to about 2000 rpm, is mixed to give the thin film fluid; and thus, this apparatus is a microreactor in which the fluid to be processed is mixed so as to cause a chemical reaction in this thin film fluid.

In the fluid processing apparatus described in Patent documents 4 and 5, it is considered that the treatment such as mixing or reaction is carried out preferably under a laminar flow condition. Under this laminar flow condition, uniform mixing by molecular diffusion is realized, resulting in realization of a homogeneous reaction, thereby forming uniform microparticles when this is accompanied with separation. Namely, in order to obtain this laminar flow condition, the processing surfaces are rotated at a comparatively slow speed; and thus, when the processing surfaces are rotated at a high speed as in the apparatus that is described in Patent Documents 6 and 7, the fluid becomes a turbulent flow, so that not only the mixing by the molecular diffusion cannot be carried out but also reactants contact with each other randomly, thereby resulting in separation of non-uniform microparticles.

Next, in Patent Documents 6 and 7, it is also described that before carrying out mixing, emulsification, and dispersion by applying a high stirring energy to the fluid to be processed between the processing surfaces, a preliminary mixing is carried out by disposing a stirring blade in the apparatus.

However, the stirring blade, too, rotates at a high speed together with the processing surfaces thereby giving the stirring energy by the high speed stirring to the fluid to be processed. For example, in the paragraph 0041 of the specification of Patent Document 6, it is described that the stirring blade is disposed in the first holder which supports one processing surfaces such that it is supported so as to be rotatable to the first holder, so that the stirring blade rotates to the first holder by receiving the feeding pressure of the fluid to be processed, and thereby preliminary dispersion of the fluid to be processed is carried out before the processing between the processing surfaces.

Accordingly, in the apparatus described in Patent Documents 6 and 7, before mixing, emulsification, and dispersion are carried out between the processing surfaces which rotate at a high rotation speed, a preliminary mixing is carried out using the high rotation speed by the stirring blade that is disposed in the apparatus. In other words, the technology disclosed is that physical treatments of the preliminary stirring treatment and the main stirring treatment are carried out in a single apparatus at the high rotation speed in the both treatments.

On the other hand, in the apparatus according to Patent Document 4, because of the microreactor, in order to control the reaction condition, the fluid to be processed that is fed to the apparatus needs to be in the state of having been completely prepared. Therefore, it has been dominantly considered that the change in the property of the fluid in the apparatus can cause an adverse effect to the homogeneity of the reaction condition.

In addition, even if the stirring blade of Patent Document 6 were used in the apparatus of Patent Document 4, the apparatus of Patent Document 4 is a microreactor which rotates at a comparatively low rotation speed as mentioned before; and thus, even if the stirring blade were added to the rotating body such as the one which rotates at a comparatively low speed, a sufficient shear force could not be given to the fluid to be processed.

Moreover, because in Patent Document 4 it is indicated that the rotation speed of the processing surfaces can influence the particle diameter of the microparticles obtained by the separation reaction (paragraphs 0269, 0350, 0418, 0458, etc., of the specification of this Document), it is clear that the rotation speed thereof can significantly influence the reaction process in the circular flow path. Therefore, in order to separate the microparticles having a target particle diameter, it is necessary to change the reaction condition by changing the rotation speed of the processing surfaces.

It must be noted here that when the stirring blade of Patent Document 6 is used in the apparatus of Patent Document 4, the stirring blade rotates with the processing surfaces. Namely, the rotation speed of the stirring blade and the shear force generated therefrom cannot be changed independently against the rotation speed of the processing surfaces, the rotation speed being required from the view point of the reaction condition.

Therefore, when the rotation speed of the processing surfaces is changed in order to separate the microparticles having a target particle diameter, with this change the rotation speed of the stirring blade and the shear force generated therefrom change as well. As a result of it, the property of the fluid to be processed that is introduced into the circular flow path changes so that the control for separation of the microparticles having a target particle diameter is very much complicated.

CITATION LIST

Patent Documents

Patent Document 1: Japanese Patent Laid-Open Publication No. 2009-214056

Patent Document 2: Japanese Patent Laid-Open Publication No. 2012-228666

Patent Document 3: Japanese Patent Laid-Open Publication No. 2009-255083

Patent Document 4: Japanese Patent Laid-Open Publication No. 2009-082902

Patent Document 5: International Patent Laid-Open Publication No. 2012/128273

Patent Document 6: Japanese Patent Laid-Open Publication No. 2004-049957

Patent Document 7: Japanese Patent Laid-Open Publication No. 2011-092941

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

The present invention intends to provide an immediately-before-stirring-type fluid processing apparatus and an immediately-before-stirring-type fluid processing method with which properties of a fluid to be processed which is introduced as a raw material into a circular flow path of a microreactor employing it as a flow path in which fluid processing is carried out can be finally adjusted and improved, the circular flow path being defined by between processing surfaces which rotate relative to each other.

Means for Solving the Problems

The present invention provides an apparatus with which final stirring, dispersion, or the like of a raw material itself to be fed to a microreactor for a reaction can be carried out in the same apparatus as the microreactor.

Namely, the present invention relates to a fluid processing apparatus, wherein the apparatus is provided with: at least two processing surfaces which are disposed in a position they are faced with each other, and a rotating mechanism which relatively rotates the two processing surfaces to each other; and the fluid processing apparatus is configured such that the at least two processing surfaces define a circular flow path through which a fluid to be processed passes, and that fluid processing of the fluid to be processed can be carried out between the at least two processing surfaces when the fluid to be processed under a state of being in a thin film fluid passes through the circular flow path from an inner side to an outer side in a radius direction thereof.

The fluid processing apparatus according to the present invention is provided with a cylindrical stirring space in an inner side of the circular flow path in a radius direction, and a stirring blade and a screen are disposed in this stirring space. Further, the apparatus is configured such that to the fluid to be processed which is immediately before being introduced into the circular flow path, a stirring energy is added by means of the stirring blade and at the same time a shear force be added between the stirring blade and the screen.

This apparatus may be equipped with a position adjusting mechanism with which a position of the screen to the stirring blade is made changeable in order to control the shear force to the fluid to be processed.

With regard to a relationship of the position between the screen and the stirring blade, the screen may be disposed outside of the stirring blade; however, it is preferable to be disposed inside thereof. Namely, from a viewpoint to efficiently give an energy to the fluid to be processed, it is preferable to configure the apparatus such that the stirring blade is disposed between the screen and an introduction port into the circulation flow path and that the fluid to be processed which is bestowed with the shear force between the screen and the stirring blade and also with the stirring energy by means of the stirring blade collides to the wall which defines the stirring space. At this time, it is suitable that both a clearance between the stirring blade and the screen and a clearance between the stirring blade and the wall are 1 mm or less; however, this does not preclude the value of more than 1 mm.

The screen may be carried out with various embodiments; for example, an embodiment may be carried out such that the screen is disposed concentrically with the stirring blade inside the stirring blade along a circumferential direction, and is provided with plural slits in the circumferential direction.

The immediately-before-stirring-type fluid processing apparatus of the present invention can be used as a microreactor, wherein it is preferably used especially as the apparatus which can make the fluid to be processed that passes through the circular flow path to cause a reaction in a thin film fluid formed under a laminar flow condition. At this time, a relative rotation number of the processing surfaces is suitable in the range of 200 to 6000 rpm, while more preferably in the range of 350 to 5000 rpm.

This can be used also as an apparatus in which the circular flow path thereof is provided with at least two introduction ports; one introduction port is open to the stirring space thereby introducing thereto a first fluid immediately after having been stirred by the stirring blade from inner side of the circular flow path; and another introduction port is open to a midway of the circular flow path thereby joining a second fluid to the first fluid which has been forced to a thin-film-like form by the processing surfaces so as to carry out the processing such as a reaction.

It is also preferable to control a distance between the processing surfaces by a balance between a pressure of the fluid to be processed which acts to a separating direction in an axial direction of a rotation of the rotating mechanism and a force applied so as to make the processing surfaces approach in the axial direction of the rotation.

The immediately-before-stirring-type fluid processing apparatus of the present invention may be carried out in such a way that the apparatus is provided with a cylindrical stirring space in an inner side of the circular flow path in a radius direction thereof, and with a stirring blade and an independent adjusting means in the stirring space.

The stirring blade rotates together with the processing surface. On the other hand, the independent adjusting means is disposed so as to be movable against the stirring blade. And, it is configured such that by movement of the independent adjusting means a stirring ability to the fluid to be processed in the stirring space may change independently to a rotation number of the processing surface.

As a typical example of the independent adjusting means, the screen may be cited; however, other than the screen, a means to adjust the flow rate to the stirring blade may be used. The stirring ability of the stirring blade changes with this flow rate adjustment so that the fluid processing capacity such as a stirring treatment added to the fluid immediately before a reaction treatment can be changed independently from the rotation number of the processing surface.

The present invention also provides a method for processing a fluid to be processed by using the immediately-before-stirring-type fluid processing apparatus as mentioned above.

At this time, it is preferable to introduce at least one fluid that constitutes the fluid to be processed directly into the circular flow path from the stirring space without passing through any other flow path after the fluid is subjected to the stirring treatment by the stirring blade. Further, it is preferable to introduce the at least one fluid that constitutes the fluid to be processed into the circular flow path within 1 second after the fluid is subjected to the stirring treatment with the stirring blade.

In addition, the present invention provides a fluid processing method wherein by using a fluid processing apparatus in which at least two processing surfaces that are disposed in a position they are faced with each other rotate relative to each other, a fluid to be processed is introduced into a circular flow path defined by the at least two processing surfaces, and the fluid to be processed that is made to a thin film fluid in between the at least two processing surfaces is made to pass through the circular flow path from an inside to an outside thereof in a radius direction thereby carrying out a reaction treatment in the thin film fluid; the method being provided with the following steps.

First, to the fluid to be processed that is before being introduced into the fluid processing apparatus, preliminary adjusting steps including a preparation treatment step to adjust a mixing and dissolution state thereof and a temperature adjusting step to adjust a temperature thereof are carried out. The fluid to be processed after having been subjected to the preliminary adjusting steps is introduced into the fluid processing apparatus, whereby before the reaction treatment is carried out in the fluid processing apparatus, an immediately-before stirring step is carried out.

In this immediately-before stirring step, a stirring blade is disposed in a cylindrical stirring space which is disposed in an inner side of the circular flow path in a radius direction thereof, and a stirring energy is given to the fluid to be processed by rotation thereof so as to carry out a stirring treatment to the fluid to be processed that is immediately before being introduced into the circular flow path. Then, the reaction treatment is carried out in the thin film fluid that is formed when the fluid to be processed is passing through between the at least two processing surfaces under a laminar flow condition.

The embodiment may be carried out by using at least two fluids of a first fluid and a second fluid as the fluid to be processed. The circular flow path is made to be provided with at least two introduction ports of a first introduction port and a second introduction port, wherein after the preliminary adjusting steps and the immediately-before stirring step are carried out to the first fluid, the first fluid is introduced into the circular flow path through the first introduction port which is open to the stirring space thereby forming a thin film form forced by the processing surfaces. The second fluid is introduced into between the processing surfaces through the second introduction port which is open to a midway of the circular flow path so as to join the second fluid to the first fluid having been made to the thin film form, so that mixing and reaction of the fluids to be processed can be carried out by molecular dispersion under the laminar flow condition.

Alternatively, a following embodiment is also suitable. Namely, the stirring blade is unpivotably fixed to a center of a holder which supports and rotates the processing surface, and thereby rotating the stirring blade and the processing surface at the same speed; and an outer circumferential edge of the stirring blade is made to have a length to an axial direction of rotation of the stirring blade, and is disposed with a clearance of 1 mm or less to a wall which defines an outer circumferential surface of the stirring space; and after a stirring energy is given to the fluid to be processed by the stirring blade, the fluid to be processed is made to collide to the wall.

Effects of the Invention

According to the present invention, the immediately-before-stirring-type fluid processing apparatus and the immediately-before-stirring-type fluid processing method can be provided in which by installing the stirring blade inside the processing surface member, homogeneity of the substance to be processed at the time of introducing the substance to be processed into between the processing surfaces can be improved so that the fluid thereof can be stably introduced into between the processing surfaces.

There is no restriction in the fluid to be processed; however, the present invention is particularly effective when a slurry having a solid body dispersed therein is processed. In addition, in the case where the fluid is fed to between the processing surfaces via a heat-exchanger, it can happen that the substance to be processed becomes inhomogeneous or re-separation due to the change in temperature; and thus, the present invention is effective for the fluid to be processed which includes the substance to be processed as mentioned above. In addition, the present invention is effective in a case where a polymer or an undissolved raw material clogs the introduction part.

In addition, there has been a case that a filter is disposed in a pipeline in order to prevent clogging due to the undissolved matters or to prevent adhesion or deposition in the introduction part, so that there have been problems such as a pressure rise when sending the fluid and a poor reproducibility due to the change in concentration of the substance to be processed. Because the stirring blade is disposed inside the processing surface member, installation of the filter is not necessary so that the flow rate can be easily controlled, and also adhesion or deposition in the introduction part can be reduced, thereby resulting in improvement in the reproducibility as well.

Because separation or ununiformity of the raw material can be totally avoided, not only clogging at the time of introduction can be avoided, but also the thin film fluid can be stabilized. Accordingly, a reaction can be carried out ideally.

In addition, because mixing can be performed immediately before the introduction part into between the processing surfaces, a step of preliminary mixing can be deleted even if this step has been absolutely necessary. In addition, in the case where the preliminary mixing generates a heat or causes decomposition or the like thereby forming harmful byproducts, because the substance to be processed can be instantaneously introduced into between the processing surfaces after it is mixed immediately before the introduction, a reaction product with a higher uniformity can be obtained.

In addition, even in the case where a strong shear force is wanted to be avoided at the time of mixing and stirring in view of the problem such as reduction in a molecular weight of the substance to be processed, because the processing apparatus has a mechanism to easily adjust the shear force only by moving the screen, the shear force can be easily adjusted in accordance with a purpose thereof.

Namely, by carrying out the embodiment in which the position adjusting mechanism with which a position of the screen is made changeable is disposed, the shear force in the immediately-before stirring treatment can be controlled independently from the rotation speed of the processing surface. As a result, at the time when the rotation speed of the processing surface is changed in order to separate the microparticles having a targeted particle diameter, even if the rotation speed of the stirring blade changes with this change, the shear force can be adjusted independently. Accordingly, various controls to achieve a targeted reaction condition or to obtain targeted microparticles can be carried out more readily.

