JPS63182003A - Pressure crystallization system for raw material of high concentration and pressure crystallization method - Google Patents

Abstract

PURPOSE:To recover specific components from raw material of a mixture efficiently in a single operation using a pressure crystallization by constituting at least the top of a high pressure container in such a way that it operates freely. CONSTITUTION:An upright high pressure container, a piston and an end cover are components of the subject system and at least the top of said container is constituted in such a way that it opens/closes freely. For instance, in a constitution in which a piston 2 shuttles back and forth from the bottom of the upright high-pressure container 1, the end cover 3 which opens/closes freely is arranged at the top. Then when a slurry raw material or solid raw material G is charged into the high pressure container 1, the piston 2 is left retreated, and the above-mentioned raw material G is introduced from the top. After this, the end cover 3 is fitted and hot liquid or slurry raw material L is injected through a flow path 4 formed in the end cover 3. Further, the piston 2 is allowed to advance to press the raw material and steps of operation after crystallization are performed. In the extraction of the aimed material S, the end cover 3 is separated and the material S is pushed up by advancing of the piston 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a pressure crystallization method and a pressure crystallization apparatus that can recover a specific component in a high yield in a single operation from a raw material mixture of a specific component and impurities. In particular, the present invention relates to a pressure crystallization method and apparatus suitable for recovering a specific component from a raw material containing a specific component that is solid at room temperature or from a high concentration raw material.

[Prior art] Pressure crystallization is a method in which a raw material (fluid phase mixture) consisting of a liquid phase or a solid/liquid mixture consisting of multiple components is introduced into a high-pressure container, and the liquid phase is closed while the drain pipe is closed. This is a method in which high pressure is applied to the raw material to promote crystallization of a specific component, and this operation results in a state in which crystals (solid phase) of the specific component and liquid phase other than the specific component coexist. Therefore, by unblocking the drain pipe, draining the liquid phase component out of the system via a filter without applying pressure to the solid-liquid coexistence state, and separating the solid-liquid without squeezing the remaining solid phase, high purity can be obtained. specific components can be obtained.

[Problems to be Solved by the Invention] The present inventors have been involved in the development and industrialization of pressure crystallization methods, and are also conducting various studies to further improve the recovery rate of specific components.

Most basically, the recovery rate can be increased by increasing the crystallization pressure. However, there is a limit to the operating pressure;
Obtaining a pressure exceeding gf/crs2 at 0 is not advantageous in terms of equipment cost.

Furthermore, if the pressure crystallization operation is repeated several times, the recovery rate of the raw material can naturally be increased, but the throughput per container volume must be sacrificed, which inevitably leads to a decrease in productivity.

In this way, it is difficult to improve the recovery rate while satisfying economic efficiency, especially when handling highly concentrated raw materials or in pressure crystallization of raw materials where the specific substance targeted for recovery is solid at room temperature. is even more difficult.

The inventors of the present invention were concerned about these circumstances and conducted further research with the aim of improving the recovery rate.

That is, FIG. 1 is a graph showing the solid-liquid equilibrium relationship of a pure substance, a mixed raw material with a certain composition ratio, and a mixed raw material with a eutectic composition ratio as a function of pressure and temperature.

a is the solid-liquid equilibrium line of the pure substance (specific component ioo%), b
C indicates the solid-liquid equilibrium line of a mixed raw material with a certain composition ratio (specific component: , indicating that it is in a solid state on the upper left side. Note that b1 point is the solid-liquid equilibrium point of the above raw material under atmospheric pressure, T1
means the melting point of a specific component under atmospheric pressure. When the above-mentioned raw material containing X% of a specific component is immersed in a pressure crystallizer and subjected to pressure crystallization, the temperature of the raw material at the time of charging into the pressure crystallizer (i.e., the temperature of the raw material under atmospheric pressure) is '
r,,T3. If it is T4, T2 in the figure is on the right side of point b1, so the raw material at that temperature will be in a liquid state, and T2 will be on the right side of point b1.
, is slightly to the left of point b1, so the raw material at that temperature takes the form of a slurry with a small amount of solids mixed in, and furthermore, at temperature T
The raw material in No. 4 is in the form of a slurry containing a considerable amount of solids. In this way, when raw materials with different temperatures and therefore properties are sealed in a device and pressurized, the pressure and temperature of each raw material will change to α, β, γ while generating heat due to pressurization.
It rises along each line and reaches points A, B, and C. Note that the points A, B, and C are set so that the vertical axis (crystallization pressure) value is the same value (maximum pressure in this case) Pl.

Then, by separating the crystallized crystals (solid phase) from the liquid phase while maintaining the pressure and squeezing the solid phase remaining in the high-pressure container, a highly pure specific component can be obtained. At this time, the specific component can be recovered in an amount corresponding to the difference in equilibrium concentration between each point A, B, and C and the solid-liquid equilibrium point b2 of the raw material at the crystallization pressure. That is, to the left of point b2 (solid phase side)
The recovery amount of the specific component increases as the distance increases, and at point 0, the largest amount of the specific component can be obtained. Therefore, it can be seen that in order to increase the recovery amount, that is, the recovery rate, it is effective to lower the temperature of the raw material as much as possible when feeding it into the pressure crystallizer. However, if the reached point after pressurization exceeds the solid-liquid equilibrium line C of the eutectic, the eutectic will be mixed into the solid phase, making it impossible to obtain a pure specific component. Therefore, it is necessary to lower the raw material charging temperature in such a range that the point reached after pressurization is as close as possible to the eutectic solid-liquid equilibrium line C, thereby increasing the recovery rate of the specific component.

However, when the charging temperature to the pressure crystallization vessel is lowered from T to T4, the solid phase content in the raw material increases and the slurry concentration increases. It is generally difficult to transport raw materials with a slurry concentration of 25 to 30% or more through pipes, and the method of lowering the raw material charging temperature in order to increase the recovery rate as described above is the method of transporting raw materials in conventional pressure crystallizers (piping transport). ), we are bound to reach a limit. In addition, the solid phase content in a slurry-like raw material with a large solid phase content is originally a solid containing impurities, and even if a pressure crystallization operation is applied to such a slurry-like raw material, specific components cannot be crystallized using solids containing impurities as nuclei. Since the process progresses, it is not possible to obtain a highly pure specific component solid.

The present invention was completed based on these research results, and was the result of further research aimed at providing a method and apparatus that can economically improve the recovery rate of specific components.

[Means for Solving the Problems] That is, the method of the present invention involves supplying a solid or slurry raw material consisting of a specific component and impurity components with a solid content concentration of 25% or more through the upper opening of a high-pressure container having a large diameter. After charging into a high-pressure container and sealing the top opening of the high-pressure container, the high-temperature liquid or solid content consisting of specific components and impurity components will be 25%.
The gist of the present invention is that a slurry-like raw material of less than The present invention relates to a pressure crystallizer comprising a piston that is movable inwardly and retractably, and an end cover that closes the open end of a high-pressure container from the side opposite to the piston, the gist of which is that at least the upper side of the high-pressure container is configured to be openable and closable. As mentioned above, in order to increase the recovery rate, it is necessary to charge low-temperature raw materials into a high-pressure container, but when the raw material charging temperature is lowered, the raw material becomes slurry-like with a high solid content, and furthermore, the fluidity of the raw material decreases. Eventually, the entire amount becomes solid. Such raw materials cannot be transported even using slurry pumps.

In the method of the present invention, the slurry raw material or solid raw material (mixture of specific components and impurity components) whose solid content concentration has increased by 25% or more by lowering the charging temperature is first inserted into a high-pressure container. do. The method is to open the lid at the top of the container to a large diameter, use a piston method, use a packet conveyor, etc.

With a reasonable slurry feeding system depending on the slurry concentration. By the way, in this state, the solid content in the charged raw material is aggregation of fine single crystals to form a lump, and liquid impurities or crystallized products of these exist in the gaps between adjacent single crystals. Furthermore, when the slurry concentration is very high, gas such as air may be present in the gaps between the lumpy solids. Furthermore, although the single crystal itself has high purity in the center, the purity decreases as it approaches the outer surface, and the outermost surface may be covered with low-purity crystals. Therefore, if the pressure crystallization operation is continued as it is, these impurities will be trapped and crystallization will proceed without being removed, making it impossible to obtain specific components of sufficient purity. is also high, reducing the efficiency of using the volume inside the container. Therefore, after sealing the high-pressure container for the purpose of increasing the purity of solid content at the time of charging or increasing the usage efficiency of the container, a high-temperature liquid raw material consisting of specific components and impurity components or a high-temperature slurry with a solid content concentration of less than 25% is prepared. The raw material is injected into a high-pressure container. There are no particular restrictions on the raw material for high-temperature injection, but for example, if the specific components and impurity components are in the same proportion as the aforementioned raw materials,
Alternatively, some or all of the solids are dissolved by heating raw materials containing different proportions to a temperature higher than that of the raw materials injected from the top of the container, or separation obtained by pre-charging pressure crystallization operation. Drainage liquid etc. can be used. By injecting this liquid or slurry high-temperature raw material, the high-temperature liquid invades the surface of the solid content in the initially charged raw material or the voids between the solid content, melts low-purity crystals or impurity crystals, and turns into a liquid phase. Transition. The temperature of the charging material system also increases. Further, by applying pressure, the solid space completely disappears. Additional supply of liquid or slurry raw material is performed by a liquid phase pump, slurry pump, etc., and is supplied under pressure as necessary, so that the internal gas space is substantially eliminated. Incidentally, as a result of the above, the solid content remaining in the slurry-like raw material becomes highly pure, and this serves as a nucleus to proceed with favorable pressure crystallization as described below. That is, as in the conventional pressure crystallization method, as the pressure inside the high-pressure container is increased, the air bubbles introduced at the raw material charging temperature are also dissolved in the liquid, and the liquid sufficiently penetrates between the solid components. At the same time, specific components in the liquid phase crystallize around the remaining solid components as nuclei. Once pressurized to a predetermined pressure, operations such as separating and discharging the liquid phase, sweating, squeezing, and taking out the specific component crystal cake in the form of a cake are performed according to the standard separation method of conventional pressure crystallization methods. By these methods, a highly purified target substance can be obtained in good yield.

In order to further increase the purity, the above-mentioned high-temperature raw material may be injected two or more times. That is, when the first pressure crystallization operation is completed, the high-temperature raw material is injected again without taking out the target substance, and then the pressure crystallization step is started. By repeating this process, the purity of the specific component can be increased. In this case, it is preferable not to perform compression for each cycle, but to perform compression only in the final cycle.

The basic structure of the method of the present invention is as shown above, but as is clear from the above explanation, when attempting to implement the method of the present invention, pipe transportation cannot be used for charging low-temperature slurry or solid materials. The raw material G must be charged into the high-pressure container 1 through the retractable supply port H (see FIG. 5) by opening the upper side of the high-pressure container. The pressure crystallizer of the present invention is intended to meet these demands, and includes a vertical high-pressure container, a piston configured to be able to advance and retreat within the container from one side of the container to the other, and a The vertical high-pressure container is provided with an end cover that closes the open end of the vertical high-pressure container, and at least the upper side of the vertical high-pressure container is configured to be openable and closable.

For example, as shown in FIG. 2, in a configuration in which a piston 2 is advanced and retracted from the lower side of a vertical high-pressure vessel 1, an end cover 3 that can be opened and closed is provided on the upper side. Slurry raw material or solid raw material G
When charging, move piston 2 backward,
Insert the raw material G from the upper side. When charging raw material G, when the slurry concentration is high, it is difficult to evaluate the charging amount because the number of voids increases. Therefore, an appropriate amount roughly corresponding to the capacity of the high-pressure container is measured in advance by weight or volume and injected. Injection is by screw feeder method (No. 7.
8), packet method, piston method, shooter method, and other methods suitable for the slurry concentration of the system to be handled are selected.

After charging the raw materials in this way, the end M3 in FIG.
is fitted, and high-temperature liquid or slurry raw material is injected from the flow path 4 formed in the end cover 3.

Thereafter, the piston 2 is advanced to pressurize the raw material, and operations after crystallization can be performed.In order to take out the target substance S, the end cap is removed and the target substance S is pushed up by the advancement of the piston 2. .

In addition, as shown in Fig. 3, if the piston 2 is moved forward and backward from the upper side of the vertical high-pressure container, a removable end cover 3 is provided at the lower end.
Place. When charging the slurry raw material or the solid raw material G, the piston 2 is pulled out, and after charging the raw material G from the upper side, the piston 2 is inserted and the inside of the high pressure container is sealed, and the inside of the end cap 3 is closed. A liquid or slurry high-temperature raw material is injected through the channel 4a formed in the flow path 4a, and a normal pressure crystallization operation is then performed. In order to take out the target substance S, the high pressure container 1 may be raised together with the piston 2.

Fig. 4 shows a modification of Fig. 3, in which a push-up mechanism K is attached to the end M3 placed on the lower end side of the high-pressure container, and when the crystallization is completed, the rod R is connected to the push-up mechanism after the piston 2 is extracted. The target substance S is advanced and pushed up, and thereby the target substance S is taken out.

In these descriptions, a structure is mentioned in which the product is removed upwardly in the form of a cake. In a pressure crystallizer, separated mother liquor is collected behind a filter or the like (not shown) built into the container, and when the lower lid is opened to take out the mother liquor, this liquid drips out downward. Therefore, a device mechanism is required to collect these dripping liquids, but when the product cake is removed from the upper lid, there is no such problem, and the remaining mother liquor flows out together with the draining liquid in the next cycle.

In addition, as shown in FIG. 6, pressure crystallizers M and Ma consisting of two sets of high-pressure containers 1, etc. are prepared for the pressurizing drive mechanism J that advances and retreats the piston 2, and one pressure crystallizer M performs crystallization. While the crystallization is in progress, the charging of the slurry or solid raw material to the other pressure crystallizer Ma is completed, and when the crystallization is completed, the pressure drive mechanism J is moved laterally to prepare it. Pressure crystallization is performed using a pressure crystallizer Ma. Thereby, the pressure crystallizer can be operated efficiently. Although two pistons 2 are used in the internal case, it is also possible to use one piston.

[Effects of the Invention] The present invention is configured as described above, and can obtain the effects summarized below.

(1) In the method of the present invention, first of all, the solid content concentration is 25
% or more of the slurry-like raw material or solid raw material is charged into the high-pressure container from the upper open part of the high-pressure container, and after the high-pressure container is sealed, the raw material is heated as necessary to remove part of the solid content or Since the high-temperature raw material, which is completely molten, is injected into the high-pressure vessel, the temperature at which the raw material is charged into the high-pressure vessel can be lowered, and specific component crystals can be obtained at a high yield.

In addition, in the case of a raw material with a high solid content, the solid content contained in the raw material contains impurities in the surface layer or between solid contents, and there are many voids, but in the method of the present invention, the high pressure container is sealed as described above. Since a high-temperature raw material with a low solid content is then injected, the above-mentioned impurities are melted and transferred to the liquid phase, and then specific components are crystallized by pressure crystallization. Therefore, it is possible to obtain specific component crystals of satisfactory purity with improved yield.

(2) By using the pressure crystallizer of the present invention, the above-described pressure crystallization method can be carried out, and high purity specific component crystals can be obtained in good yield.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the solid-liquid equilibrium point in adiabatic pressure crystallization as a function of pressure and temperature, and Figs. 2 to 4 are flow explanatory diagrams showing the pressure crystallizer and pressure crystallization method according to the present invention. , and FIGS. 5 to 8 are schematic diagrams showing modified embodiments of the present invention. 1... High pressure container 2... Piston 3... End cap 4... Channel G... Slurry raw material or solid raw material with solid content of 25% or more

Claims (4)

[Claims] (1) Pressure consisting of a rigid high-pressure container, a piston that can advance and retreat within the high-pressure container from one side of the high-pressure container to the other, and an end cover that closes the open end of the high-pressure container from the opposite side of the piston. 1. A pressure crystallizer, characterized in that at least the upper side of the high-pressure container is configured to be openable and closable. (2) a device for dividing a slurry-like raw material into a predetermined amount consisting of a specific component and an impurity component with a solid content concentration of 25% or more;
A patent claim that includes a high-concentration slurry supply device that injects the divided raw material from the upper opening of the high-pressure container, and at least the latter is movable relative to the upper opening of the high-pressure container. The pressure crystallizer according to item 1. (3) The pressure crystallizer according to claim 1 or 2, further comprising a take-out mechanism for taking out the product cake from the upper end opening of the high-pressure container. (4) When performing a crystallization method that uses pressure as a variable, a solid or slurry raw material consisting of a specific component and impurity components with a solid content concentration of 25% or more is introduced into a high-pressure container from the upper opening of the high-pressure container. After charging and sealing the upper opening of the high-pressure vessel, a high-temperature liquid or slurry raw material with a solid content concentration of less than 25% consisting of specific components and impurity components is injected through piping, and then subjected to the pressure crystallization process. A pressure crystallization method for highly concentrated raw materials characterized by migration.