Anti-solvent crystallizer and crystallization method

Abstract

The application discloses an anti-solvent crystallizer and a crystallization method. The anti-solvent crystallizer comprises a crystallizer main body, wherein the crystallizer main body comprises a tapering section, a raw material liquid section, a first anti-solvent section and a gradual expansion section which are sequentially communicated, and flow channels of the tapering section, the raw material liquid section, the first anti-solvent section and the gradual expansion section form a crystallization channel; a ring gap is arranged between the tapering section and the raw material liquid section, the raw material liquid section and the first anti-solvent section are both provided with a buffer cavity between an inner wall of the crystallizer main body, raw material liquid feeding pipes and first anti-solvent feeding pipes are arranged on the crystallizer main body at intervals, and the raw material liquid feeding pipes and the first anti-solvent feeding pipes are communicated with the raw material liquid section and the first anti-solvent section through the buffer cavities respectively. The application discloses an anti-solvent crystallizer and a crystallization method, and solves the problem that the use effect provided by an existing anti-solvent crystallizer is not ideal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial crystallization, and more particularly to an anti-solvent crystallizer and a crystallization method. BACKGROUND

[0002] Anti-solvent crystallization belongs to a rapid crystallization process. A common anti-solvent crystallizer is a kettle type crystallizer. The kettle type crystallizer is widely used due to its simple process, convenient operation, and strong applicability. However, the kettle type crystallizer is usually operated intermittently, and has problems of poor mixing effect and long mixing time. Poor mixing effect in the crystallizer will lead to excessively high local supersaturation, which may affect the crystal morphology, purity, and particle size distribution.

[0003] Therefore, there is a need for an anti-solvent crystallizer and a crystallization method to solve the above problems. SUMMARY

[0004] Therefore, the present application aims to provide an anti-solvent crystallizer and a crystallization method to solve the problem of unsatisfactory use effect of the existing anti-solvent crystallizer.

[0005] To achieve the above purpose, the present application provides an anti-solvent crystallizer, which comprises:

[0006] A crystallizer body, the crystallizer body comprises a tapering section, a raw material liquid section, a first anti-solvent section, and a gradual expansion section which are sequentially connected, and flow channels of the tapering section, the raw material liquid section, the first anti-solvent section, and the gradual expansion section form a crystallization channel; an annular gap is arranged between the tapering section and the raw material liquid section, the raw material liquid section and the first anti-solvent section each have a buffer cavity between the inner wall of the crystallizer body, at least one raw material liquid feeding pipe and at least one first anti-solvent feeding pipe are arranged on the crystallizer body at intervals, and the raw material liquid feeding pipe and the first anti-solvent feeding pipe are respectively communicated with the raw material liquid section and the first anti-solvent section through the buffer cavity.

[0007] Optionally, the crystallizer body further comprises at least one second anti-solvent section, the second anti-solvent section is connected between the first anti-solvent section and the gradual expansion section, a flow channel of the second anti-solvent section is communicated with the crystallization channel, the second anti-solvent section has the buffer cavity between the inner wall of the crystallizer body, and at least one second anti-solvent feeding pipe is arranged on the crystallizer body, and the second anti-solvent feeding pipe is communicated with the second anti-solvent section through the buffer cavity.

[0008] Optionally, at least one supplementary raw material liquid feeding pipe is arranged on the crystallizer body, and the supplementary raw material liquid feeding pipe is communicated with the crystallization channel through the first anti-solvent section or the second anti-solvent section.

[0009] Optionally, the crystallizer body comprises a converging pipe, a first shell, a second shell, a third shell and a diverging pipe connected in sequence, and a raw material liquid jacket pipe, a first anti-solvent jacket pipe and a second anti-solvent jacket pipe are arranged in the first shell, the second shell and the third shell in sequence.

[0010] The converging pipe and the diverging pipe form the converging section and the diverging section respectively; the first shell and the raw material liquid jacket pipe form the raw material liquid section; the second shell and the first anti-solvent feed pipe form the first anti-solvent section; the third shell and the second anti-solvent feed pipe form the second anti-solvent section.

[0011] The raw material liquid feed pipe, the first anti-solvent feed pipe, the supplementary raw material liquid feed pipe and the second anti-solvent feed pipe are arranged on at least one of the first shell, the second shell and the third shell.

[0012] Optionally, the buffer cavity comprises a first buffer cavity arranged in the first shell, the raw material liquid jacket pipe is arranged at least partially in the first buffer cavity, at least one feed hole is arranged on the raw material liquid jacket pipe, a circumferential gap is arranged between the raw material liquid jacket pipe and the converging pipe, and the raw material liquid feed pipe is arranged on the first shell and communicates with the crystallization channel through the first buffer cavity, the feed hole and the circumferential gap.

[0013] Optionally, the inlet end of the raw material liquid jacket pipe comprises a connecting pipe section and an inlet pipe section connected in sequence, the connecting pipe section is sleeved outside the converging pipe, the circumferential gap is formed between the connecting pipe section and the converging pipe, and the feed hole is arranged on the connecting pipe section; the inner diameter of the inlet pipe section is smaller than the inner diameter of the converging pipe.

[0014] Optionally, a plurality of protrusions are arranged in the raw material liquid jacket pipe and spaced along the axial direction, and the protrusions are used to reduce the passage area of the raw material liquid jacket pipe.

[0015] Optionally, the buffer cavity comprises a second buffer cavity arranged in the second shell, the first anti-solvent jacket pipe is arranged at least partially in the second buffer cavity, at least one first dispersion hole is arranged on the first anti-solvent jacket pipe, the first anti-solvent feed pipe is arranged on the second shell and communicates with the crystallization channel through the second buffer cavity and the first dispersion hole.

[0016] Optionally, the buffer cavity comprises a third buffer cavity arranged in a third shell, the first anti-solvent sleeve is at least partially arranged in the third buffer cavity, at least one second dispersion hole is arranged on the first anti-solvent sleeve, and the supplementary raw material liquid feeding pipe is arranged on the third shell, and the supplementary raw material liquid feeding pipe communicates with the crystallization channel through the third buffer cavity and the second dispersion hole.

[0017] Optionally, the buffer cavity comprises a fourth buffer cavity arranged in a third shell, the second anti-solvent sleeve is at least partially arranged in the fourth buffer cavity, at least one third dispersion hole is arranged on the second anti-solvent sleeve, and the second anti-solvent sleeve is arranged on the third shell, and the second anti-solvent sleeve communicates with the crystallization channel through the fourth buffer cavity and the third dispersion hole.

[0018] Optionally, at least one guide plate is arranged in the second anti-solvent sleeve.

[0019] The application also provides a crystallization method using the anti-solvent crystallizer as described above, comprising:

[0020] (1) The raw material liquid enters the raw material liquid section from the raw material liquid feeding pipe through the buffer cavity, the anti-solvent enters the raw material liquid section from the tapered section through the annular gap to mix with the raw material liquid, the crystallization channel precipitates crystals to form a mixed fluid;

[0021] (2) The mixed fluid enters the first anti-solvent section, the anti-solvent enters the first anti-solvent section from the first anti-solvent feeding pipe through the buffer cavity to mix with the mixed fluid, the crystallization channel precipitates crystals, and the crystals are discharged from the diverging section.

[0022] Optionally, the crystallizer body further comprises at least one second anti-solvent section, at least one second anti-solvent feeding pipe is arranged on the crystallizer body, and step (2) further comprises: the mixed fluid in the first anti-solvent section enters the second anti-solvent section, the anti-solvent enters the second anti-solvent section from the second anti-solvent feeding pipe through the buffer cavity to mix with the mixed fluid, and the crystallization channel precipitates crystals.

[0023] Optionally, at least one supplementary raw material liquid feeding pipe is arranged on the crystallizer body, and step (2) further comprises: the supplementary raw material liquid feeding pipe supplements the raw material liquid to the crystallization channel through the first anti-solvent section or the second anti-solvent section.

[0024] Optionally, the crystallizer body comprises a tapered pipe, a first shell, a second shell, a third shell and a diverging pipe connected in sequence; a raw material liquid sleeve, a first anti-solvent sleeve and a second anti-solvent sleeve are arranged in the first shell, the second shell and the third shell in sequence;

[0025] Step (1) comprises: the raw material liquid enters the raw material liquid jacket from the raw material liquid feeding pipe, and the anti-solvent enters the raw material liquid jacket from the tapered pipe to mix with the raw material liquid;

[0026] Step (2) comprises: the mixed fluid enters the first anti-solvent jacket, the anti-solvent enters the first anti-solvent jacket from the first anti-solvent feeding pipe to mix with the mixed fluid, the crystallization channel precipitates crystals, and the mixed fluid with increased concentration is formed; the raw material liquid supplement feeding pipe supplements the raw material liquid to the crystallization channel through the first anti-solvent jacket or the second anti-solvent jacket; the mixed fluid with increased concentration and the raw material liquid supplement enter the second anti-solvent jacket, the anti-solvent enters the second anti-solvent jacket from the second anti-solvent feeding pipe to mix with the mixed fluid with increased concentration and the raw material liquid supplement, and the crystallization channel precipitates crystals.

[0027] Optionally, the buffer cavity comprises a first buffer cavity arranged in the first shell, the raw material liquid jacket is arranged at least partially in the first buffer cavity, at least one feeding hole is arranged on the raw material liquid jacket, a circumferential gap is arranged between the raw material liquid jacket and the tapered pipe, and the raw material liquid feeding pipe is arranged on the first shell; step (1) further comprises: the raw material liquid enters the crystallization channel in sequence through the raw material liquid feeding pipe, the first buffer cavity, the feeding hole and the circumferential gap.

[0028] Optionally, the buffer cavity comprises a second buffer cavity arranged in the second shell, the first anti-solvent jacket is arranged at least partially in the second buffer cavity, at least one first dispersion hole is arranged on the first anti-solvent jacket, and the first anti-solvent feeding pipe is arranged on the second shell; step (2) further comprises: the anti-solvent enters the crystallization channel in sequence through the first anti-solvent feeding pipe, the second buffer cavity and the first dispersion hole.

[0029] Optionally, the buffer cavity comprises a third buffer cavity arranged in the third shell, the first anti-solvent jacket is arranged at least partially in the third buffer cavity, at least one second dispersion hole is arranged on the first anti-solvent jacket, and the raw material liquid supplement feeding pipe is arranged on the third shell; step (2) further comprises: the raw material liquid supplement enters the crystallization channel in sequence through the raw material liquid supplement feeding pipe, the third buffer cavity and the second dispersion hole.

[0030] Optionally, the buffer cavity comprises a fourth buffer cavity arranged in the third shell, the second anti-solvent jacket is arranged at least partially in the fourth buffer cavity, at least one third dispersion hole is arranged on the second anti-solvent jacket, and the second anti-solvent jacket is arranged on the third shell; step (2) further comprises: the anti-solvent enters the crystallization channel in sequence through the second anti-solvent jacket, the fourth buffer cavity and the third dispersion hole.

[0031] Optionally, step (2) further comprises: changing the crystal shape and particle size by adjusting the relative feed rates of the feed liquid and the anti-solvent; and / or changing the crystal shape and particle size by adjusting the feed flow pattern of the first anti-solvent jacket and the second anti-solvent jacket.

[0032] Optionally, step (2) further comprises: increasing the feed rate of at least one of the tapered tube, the first anti-solvent feed tube, the second anti-solvent jacket, and / or decreasing the feed rate of the feed liquid feed tube; and feeding the first anti-solvent jacket and the second anti-solvent jacket with the first dispersion hole in the radial feed direction to obtain fiber-shaped precipitated crystals.

[0033] Optionally, step (2) further comprises: decreasing the feed rate of at least one of the tapered tube, the first anti-solvent feed tube, the second anti-solvent jacket, and / or increasing the feed rate of the feed liquid feed tube; and feeding the first anti-solvent jacket and the second anti-solvent jacket with the second dispersion hole in the tangential feed direction, the additional feed liquid feed tube providing additional feed liquid, to obtain spherical precipitated crystals.

[0034] As can be seen from the above, the anti-solvent crystallizer and the crystallization method provided by the present application have the following advantages compared with the prior art: the above-mentioned anti-solvent crystallizer, the buffer cavity provides a buffering effect for the feed liquid and the anti-solvent entering the crystallization channel; the anti-solvent enters the crystallization channel from the tapered section and the first anti-solvent section respectively, by setting multiple anti-solvent entering, a controllable solute supersaturation gradient can be formed in the crystallization channel; the annular gap is conducive to the anti-solvent fluid shearing the feed liquid, so that the feed liquid entering the clean channel is in a dispersed phase, the feed liquid and the anti-solvent can be fully mixed in a short time, the mixing between the fluids in the channel is strengthened, and then a product with controllable crystal particle size and shape is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0035] The above features and technical advantages of the present application will become more apparent and easier to understand through the following description of its embodiments, in conjunction with the accompanying drawings.

[0036] Figure 1 It is a schematic diagram of the anti-solvent crystallizer used in the specific embodiments of the present application.

[0037] Figure 2 It is a schematic diagram of the anti-solvent crystallizer used in the specific embodiments of the present application. Figure 1 It is an exploded view of the anti-solvent crystallizer shown in the figure.

[0038] Figure 3 It is a schematic diagram of the anti-solvent crystallizer used in the specific embodiments of the present application. Figure 1

[0039] Figure 4 Figure 1 ​​Schematic view of the first anti-solvent jacket of the anti-solvent crystallizer shown.

[0040] Figure 5 Schematic view of the first anti-solvent jacket of the anti-solvent crystallizer employed in another embodiment.

[0041] Figure 6 Schematic view of the second anti-solvent jacket of the anti-solvent crystallizer shown. Figure 1 Schematic view of the second anti-solvent jacket of the anti-solvent crystallizer shown.

[0042] Wherein the reference signs:

[0043] 1. Converging pipe; 2. Feed hole; 3. Raw material liquid feed pipe; 4. Raw material liquid jacket pipe; 41. Connecting pipe section; 42. Inlet pipe section; 5. Second shell; 6. First anti-solvent feed pipe; 7. First anti-solvent jacket pipe; 8. Supplementary raw material liquid feed pipe; 9. Third shell; 10. Second anti-solvent feed pipe; 11. Second anti-solvent jacket pipe; 12. Diverging pipe; 14. First shell; 15. Protrusion; 16. First dispersion hole; 16-1. Tangential dispersion hole; 16-1. Radial dispersion hole; 17. Second dispersion hole; 18. Third dispersion hole; 19. Baffle; 20. Diverging hole. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to specific embodiments and with reference to the drawings. Identical parts are denoted by identical reference signs in the following description. It should be noted that the words "front", "back", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings. The words "inner" and "outer" are used to refer to the directions towards or away from the geometric center of a particular part.

[0045] Figure 1 Schematic view of the anti-solvent crystallizer employed in the specific embodiments of the present application. Figure 2 Schematic view of the anti-solvent crystallizer shown. Figure 1 Exploded view of the anti-solvent crystallizer shown. As shown in Figure 1 and Figure 2 The anti-solvent crystallizer comprises a crystallizer body.

[0046] The crystallizer body comprises a converging section, a raw material liquid section, a first anti-solvent section and a diverging section which are sequentially connected in communication, and the flow channels of the converging section, the raw material liquid section, the first anti-solvent section and the diverging section form a crystallization channel; an annular gap is provided between the converging section and the raw material liquid section, and the raw material liquid section and the first anti-solvent section each has a buffer cavity with the inner wall of the crystallizer body, and the raw material liquid feed pipe 3 and the first anti-solvent feed pipe 6 are provided on the crystallizer body at intervals and communicate with the raw material liquid section and the first anti-solvent section through the buffer cavities.

[0047] The raw material liquid enters the raw material liquid section through the buffer cavity and the annular gap from the raw material liquid inlet pipe 3, the anti-solvent enters the passage of the raw material liquid section from the flow channel of the taper section to mix with the raw material liquid, and the precipitation process is completed; the mixed fluid enters the passage of the first anti-solvent section to mix with the anti-solvent entering from the first anti-solvent inlet pipe 6 through the buffer cavity, further increasing the solute supersaturation, so that the solvent in the crystal obtained by precipitation is precipitated, and is discharged from the gradual expansion section.

[0048] The above anti-solvent crystallizer has the buffer cavity providing the buffer effect for the raw material liquid and the anti-solvent entering the crystallization passage; the anti-solvent enters the crystallization passage from the taper section and the first anti-solvent section respectively, and the controllable solute supersaturation gradient can be formed in the crystallization passage by setting multiple anti-solvent entering; the annular gap is beneficial to the anti-solvent fluid shearing the raw material liquid, so that the raw material liquid entering the clean passage is in the dispersed phase, the raw material liquid and the anti-solvent can be fully mixed in a short time, the mixing between the fluids in the passage is strengthened, and then the product with controllable crystal size and shape is obtained.

[0049] Optionally, the crystallizer body further comprises at least one second anti-solvent section, the second anti-solvent section is communicated between the first anti-solvent section and the gradual expansion section, the flow channel of the second anti-solvent section is communicated with the crystallization passage, and the buffer cavity is formed between the second anti-solvent section and the inner wall of the crystallizer body; at least one second anti-solvent inlet pipe 10 is arranged on the crystallizer body, and the second anti-solvent inlet pipe 10 is communicated with the second anti-solvent section through the buffer cavity. The mixed fluid of the first anti-solvent section enters the second anti-solvent section along the axial direction to mix with the anti-solvent entering from the second anti-solvent inlet pipe 10 through the buffer cavity, further increasing the solute supersaturation, so that the solvent wrapped by the crystal is completely precipitated. The anti-solvent is fed at least in two groups, and the controllable solute supersaturation gradient can be formed in the crystallization passage by setting multiple anti-solvent entering.

[0050] Optionally, at least one supplementary raw material inlet pipe 8 is arranged on the crystallizer body, and the supplementary raw material inlet pipe 8 is communicated with the crystallization passage through the first anti-solvent section or the second anti-solvent section. The supplementary raw material inlet pipe 8 is arranged between the first anti-solvent section and the second anti-solvent section, and the supplementary raw material liquid enters the first anti-solvent section and the second anti-solvent section from the supplementary raw material inlet pipe 8 through the buffer cavity. The raw material liquid is fed at least in two groups, and the controllable solute supersaturation gradient can be formed in the crystallization passage by setting multiple raw material liquid entering.

[0051] Optionally, the crystallizer body comprises a converging pipe 1, a first shell 14, a second shell 5, a third shell 9 and a diverging pipe 12 connected in sequence, the first shell 14, the second shell 5 and the third shell 9 are sequentially provided with a raw material liquid jacket pipe 4, a first anti-solvent jacket pipe 7 and a second anti-solvent jacket pipe 11, the converging pipe 1 and the diverging pipe 12 form a converging section and a diverging section respectively, the first shell 14 and the raw material liquid jacket pipe 4 form a raw material liquid section, the second shell 5 and the first anti-solvent feeding pipe 6 form a first anti-solvent section, the third shell 9 and the second anti-solvent feeding pipe 10 form a second anti-solvent section, and the raw material liquid feeding pipe 3, the first anti-solvent feeding pipe 6, the supplementary raw material feeding pipe 8 and the second anti-solvent feeding pipe 10 are arranged on at least one of the first shell 14, the second shell 5 and the third shell 9. The anti-solvent crystallizer has a Venturi structure, and the raw material liquid and the anti-solvent enter multiple times, and when the anti-solvent / raw material liquid ratio is small, the suction effect of the Venturi structure is utilized, so that a pumping system is no longer needed, thereby simplifying the structure. Moreover, the raw material liquid or the anti-solvent is first dispersed by the buffer chamber and then enters the crystallization channel, so that the appearance of block-shaped crystals caused by local high concentration in the crystallization channel is effectively avoided.

[0052] In an embodiment of the present application, the structures of the converging pipe 1, the first shell 14, the raw material liquid jacket pipe 4, the second shell 5, the first anti-solvent jacket pipe 7, the third shell 9, the second anti-solvent jacket pipe 11 and the diverging pipe 12 are fixedly connected or detachably connected in pairs, for example, the converging pipe 1 and the first shell 14 are clamped and connected, and the raw material liquid jacket pipe 4 is clamped and connected with the first shell 14 and the second shell 5 respectively. The raw material liquid feeding pipe 3 is arranged on the first shell 14, the first anti-solvent feeding pipe 6 is arranged on the second shell 5, and the supplementary raw material feeding pipe 8 and the second anti-solvent feeding pipe 10 are arranged on the third shell 9.

[0053] In an embodiment of the present application, the flow channel in the converging pipe 1 comprises a converging section and a straight section connected in sequence, the converging section is used for feeding, and the straight section is used for discharging.

[0054] In an embodiment of the present application, the flow channel in the diverging pipe 12 comprises a straight section and a diverging section connected in sequence, the straight section is used for feeding, and the diverging section (i.e. the diverging hole 20) is used for discharging.

[0055] In an embodiment of the present application, the raw material liquid jacket pipe 4 is in a stepped shape, the first anti-solvent jacket pipe 7 is in an approximate cross shape, and the second anti-solvent jacket pipe 11 is in an approximate cross shape.

[0056] Figure 3 For Figure 1 the raw material liquid jacket pipe of the anti-solvent crystallizer is shown. As Figure 3 shown, the anti-solvent crystallizer comprises a raw material liquid jacket pipe 4.

[0057] Optionally, the buffer cavity comprises a first buffer cavity arranged in the first shell 14, the raw material liquid jacket pipe 4 is arranged at least partially in the first buffer cavity, the raw material liquid jacket pipe 4 is provided with at least one feeding hole 2, and an annular gap is arranged between the raw material liquid jacket pipe 4 and the tapered pipe 1. The raw material liquid feeding pipe 3 is arranged on the first shell 14, and the raw material liquid feeding pipe 3 is communicated with the crystallization channel through the first buffer cavity, the feeding hole 2 and the annular gap. The raw material liquid first enters the first buffer cavity composed of the raw material liquid jacket pipe 4 and the first shell 14 through the raw material liquid feeding pipe 3, and then enters the crystallization channel through the annular gap composed of the tapered pipe 1 and the raw material liquid jacket pipe 4 through the circumferentially arranged feeding hole 2. The raw material liquid is mixed with the anti-solvent entering through the tapered pipe 1 in a very short time to complete the precipitation process. By using the above-mentioned raw material liquid jacket pipe 4 structure, the first buffer cavity can provide a buffering effect, and the annular gap is beneficial to the anti-solvent fluid shearing the raw material liquid, so that the raw material liquid entering the flow channel is in a dispersed phase, and the raw material liquid and the anti-solvent can be fully mixed in a short time.

[0058] In an embodiment of the present application, the tapered pipe 1, the first shell 14 and the second shell 5 are sequentially clamped and connected, the tapered pipe 1 partially extends into the first shell 14, and the opposite ends of the raw material liquid jacket pipe 4 are located in the first shell 14 and the second shell 5 respectively.

[0059] In an embodiment of the present application, the feeding hole 2 extends along the radial direction of the raw material liquid jacket pipe 4, and a plurality of feeding holes 2 are uniformly distributed in the circumferential direction of the raw material liquid jacket pipe 4.

[0060] Optionally, the inlet end of the raw material liquid jacket pipe 4 comprises a connecting pipe section 41 and an inlet pipe section 42 which are sequentially communicated, the connecting pipe section 41 is sleeved outside the tapered pipe 1, an annular gap is formed between the connecting pipe section 41 and the tapered pipe 1, and the feeding hole 2 is arranged on the connecting pipe section 41; the inner diameter of the inlet pipe section 42 is smaller than the inner diameter of the tapered pipe 1. The channel diameter of the connecting pipe section 41 is larger than the diameter of the straight section of the tapered pipe 1, the channel diameter of the inlet pipe section 42 is smaller than the diameter of the straight section of the tapered pipe 1, the annular gap formed has a stepped shape, the annular gap is generally 1-3 mm, and the annular gap is beneficial to the anti-solvent fluid shearing the raw material liquid, so that the raw material liquid entering the flow channel is in a dispersed phase. By using the above-mentioned raw material liquid jacket pipe 4, the raw material liquid and the anti-solvent can be fully mixed in the raw material liquid jacket pipe 4 under the action of the annular gap.

[0061] Optionally, a plurality of protrusions 15 are arranged in the raw material liquid jacket pipe 4 and are spaced apart along the axial direction, and the protrusions 15 are used to reduce the passage area of the raw material liquid jacket pipe 4. By using the above-mentioned raw material liquid jacket pipe 4 with protrusions 15, the protrusions 15 increase the degree of turbulence in the crystallization channel, which is helpful for full mixing.

[0062] In an embodiment of the present application, the protrusions 15 protrude towards the flow channel of the raw material liquid jacket pipe 4, the protrusions 15 are arranged in an array on the raw material liquid jacket pipe 4, a plurality of protrusions 15 are uniformly distributed in the circumferential direction of the raw material liquid jacket pipe 4, and the plurality of protrusions 15 are spaced apart along the axial direction of the raw material liquid jacket pipe 4. The protrusions 15 have a circumferential semi-circular structure, the height of the protrusions 15 is 1 / 5 of the inner diameter of the crystallization channel, and the distance between two rows of protrusions 15 is one diameter of the crystallization channel.

[0063] Figure 4 As shown in FIG. 1, the anti-solvent crystallizer comprises a first anti-solvent jacket pipe 7. Figure 1 As shown in FIG. 1, the anti-solvent crystallizer comprises a first anti-solvent jacket pipe 7. Figure 4

[0064] Optionally, the buffer cavity comprises a second buffer cavity arranged in the second shell 5, the first anti-solvent jacket pipe 7 is at least partially arranged in the second buffer cavity, at least one first dispersion hole 16 is arranged on the first anti-solvent jacket pipe 7, and the first anti-solvent feeding pipe 6 is arranged on the second shell 5 and communicates with the crystallization channel through the second buffer cavity and the first dispersion hole 16. The anti-solvent enters the second buffer cavity composed of the second shell 5 and the first anti-solvent jacket pipe 7 through the first anti-solvent feeding pipe 6, and enters the crystallization channel through the circumferentially arranged first dispersion hole 16. As the anti-solvent enters through the first dispersion hole 16, the supersaturation of the solute in the axial direction increases. By using the above-mentioned first anti-solvent jacket pipe 7, the second buffer cavity can provide a buffering effect, and the mixed fluid and the anti-solvent can be fully mixed in a short time.

[0065] In an embodiment of the present application, the first shell 14, the second shell 5 and the third shell 9 are connected in sequence, and the opposite ends of the first anti-solvent jacket pipe 7 are located in the second shell 5 and the third shell 9, respectively.

[0066] The first dispersion hole 16 has two feeding directions of tangential and radial directions, and the first anti-solvent jacket pipe 7 can be replaced according to process requirements and different particle properties. In an embodiment of the present application, the first dispersion hole 16 extends along the tangential direction of the first anti-solvent jacket pipe 7, i.e. the tangential dispersion hole 16-1, the first dispersion hole 16 is arranged in an array on the first anti-solvent jacket pipe 7, a plurality of first dispersion holes 16 are uniformly distributed in the circumferential direction of the first anti-solvent jacket pipe 7, and the plurality of first dispersion holes 16 are spaced apart along the axial direction of the first anti-solvent jacket pipe 7. The first dispersion hole 16 is arranged in the circumferential direction of the first anti-solvent jacket pipe 7 and is arranged in three layers in the axial direction, the diameter of the first dispersion hole 16 is 0.5-2 mm, and the number of the first dispersion holes 16 in each layer is 7-12.

[0067] Figure 5 As shown in FIG. 1, the anti-solvent crystallizer comprises a first anti-solvent jacket pipe 7. Figure 5 ​As shown, in another embodiment of the present application, the first dispersion hole 16 extends along the radial direction of the first anti-solvent sleeve 7, i.e. the radial dispersion hole 16-2, and the remaining arrangement can refer to the above-mentioned embodiment, which will not be described here.

[0068] Optionally, the buffer cavity comprises a third buffer cavity arranged in the third shell 9, the first anti-solvent sleeve 7 is at least partially arranged in the third buffer cavity, at least one second dispersion hole 17 is arranged on the first anti-solvent sleeve 7, and the supplemental raw material feeding pipe 8 is arranged on the third shell 9, and the supplemental raw material feeding pipe 8 communicates with the crystallization channel through the third buffer cavity and the second dispersion hole 17. The supplemental raw material liquid enters the third buffer cavity composed of the first anti-solvent sleeve 7 and the third shell 9 through the supplemental raw material feeding pipe 8, and enters the crystallization channel through the second dispersion hole 17; by using the above-mentioned supplemental raw material feeding pipe 8, the supplemental raw material liquid is provided, and the third buffer cavity can provide a buffering effect, so that the raw material liquid and the anti-solvent can be fully mixed in a short time.

[0069] In an embodiment of the present application, the third shell 9 is provided with a partition plate distributed oppositely, the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11 communicate between the partition plates, the third buffer cavity is between the first anti-solvent sleeve 7 and the partition plate, and the fourth buffer cavity is between the second anti-solvent sleeve 11 and the partition plate.

[0070] In an embodiment of the present application, the second dispersion hole 17 extends along the tangential direction of the first anti-solvent sleeve 7, and a plurality of second dispersion holes 17 are uniformly distributed in the circumferential direction of the first anti-solvent sleeve 7. For example, the diameter of the second dispersion hole 17 is 0.25-1mm, and the number of second dispersion holes 17 in each layer is 7-12.

[0071] In another embodiment of the present application, the second dispersion hole 17 extends along the radial direction of the first anti-solvent sleeve 7, and the remaining arrangement can refer to the above-mentioned embodiment, which will not be described here.

[0072] Figure 6 For Figure 1 The schematic diagram of the second anti-solvent sleeve of the anti-solvent crystallizer. As Figure 6As shown, the anti-solvent crystallizer comprises a second anti-solvent jacket 11. Optionally, the buffer cavity comprises a fourth buffer cavity arranged in the third shell 9, the second anti-solvent jacket 11 is arranged at least partially in the fourth buffer cavity, at least one third dispersion hole 18 is arranged on the second anti-solvent jacket 11, the second anti-solvent jacket 11 is arranged on the third shell 9, and the second anti-solvent jacket 11 communicates with the crystallization channel through the fourth buffer cavity and the third dispersion hole 18. The anti-solvent enters the fourth buffer cavity composed of the third shell 9 and the second anti-solvent jacket 11 through the second anti-solvent feeding pipe 10, and enters the crystallization channel through the circumferentially arranged third dispersion hole 18; as the anti-solvent enters through the third dispersion hole 18, the supersaturation of the solute in the axial direction increases. By using the above-mentioned second anti-solvent jacket 11, the fourth buffer cavity can provide a buffering effect, and the mixed fluid and the anti-solvent can be fully mixed in a short time.

[0073] In an embodiment of the present application, the first shell 14, the second shell 5 and the third shell 9 are connected in sequence, and the opposite ends of the second anti-solvent jacket 11 are located in the third shell 9 and the converging pipe 12, respectively.

[0074] The third dispersion hole 18 has two feeding directions of tangential and radial directions, and according to process requirements and different particle properties, the second anti-solvent jacket 11 can be replaced; in an embodiment of the present application, the third dispersion hole 18 extends along the tangential direction of the second anti-solvent jacket 11, the third dispersion hole 18 is arranged in an array on the second anti-solvent jacket 11, a plurality of third dispersion holes 18 are uniformly distributed in the circumferential direction of the second anti-solvent jacket 11, and the plurality of third dispersion holes 18 are spaced apart in the axial direction of the second anti-solvent jacket 11. For example, the third dispersion hole 18 is arranged along the circumferential direction of the second anti-solvent jacket 11, and three layers are arranged in the axial direction, the diameter of the third dispersion hole 18 is 0.5-2mm, and the number of third dispersion holes 18 in each layer is 7-12.

[0075] In another embodiment of the present application, the third dispersion hole 18 extends along the radial direction of the second anti-solvent jacket 11, and the remaining arrangement can refer to the above-mentioned embodiment, which will not be described here.

[0076] Optionally, at least one flow guide plate 19 is arranged in the second anti-solvent jacket 11. The fluid flow direction is changed from tangential flow to axial flow through the guiding action of the flow guide plate 19.

[0077] In an embodiment of the present application, the number of flow guide plates 19 is a plurality, the plurality of flow guide plates 19 are uniformly distributed along the circumferential direction of the second anti-solvent jacket 11, and the flow guide plates 19 extend along the axial direction of the second anti-solvent jacket 11. The height of the flow guide plate 19 is 1 / 10 of the channel diameter of the second anti-solvent jacket 11.

[0078] The use process of the anti-solvent crystallizer will be further introduced below.

[0079] Example 1: The tapered pipe 1, the raw material liquid jacket pipe 4, the first anti-solvent jacket pipe 7, the second anti-solvent jacket pipe 11 and the gradual expansion pipe 12 are connected in sequence to form a Venturi-tube-shaped crystallization channel structure; the anti-solvents enter the crystallization channel through the tapered pipe 1, the first anti-solvent feeding pipe 6 and the second anti-solvent feeding pipe 10, respectively; and the raw material liquid enters the crystallization channel through the raw material liquid feeding pipe 3 and the supplementary raw material feeding pipe 8, respectively.

[0080] Example 2: The anti-solvent crystallizer is used to prepare potassium bicarbonate powder, and anhydrous ethanol is used as the anti-solvent and the aqueous potassium bicarbonate solution is used as the raw material liquid at room temperature. The potassium bicarbonate is insoluble in anhydrous ethanol, but the water and the anhydrous ethanol are mutually soluble, and the potassium bicarbonate crystals are precipitated. The inlet diameter of the tapered pipe 1 is 74 mm, the inner diameter of the crystallization channel is 24 mm, the annular gap is 2 mm, the first dispersion hole 16 and the third dispersion hole 18 adopt the radial flow direction, and the hole diameter is 2 mm, and the supplementary raw material liquid feeding is not needed. The anti-solvent flow rate of the tapered pipe 1 is 200 L / h, the anti-solvent flow rate of the first anti-solvent feeding pipe 6 and the second anti-solvent feeding pipe 10 is 50 L / h, the anti-solvent is fed first at the beginning of crystallization, and the internal flow is stable. The raw material liquid flow rate is 20 L / h, and the raw material liquid enters the annular gap from the raw material liquid feeding pipe 3, then enters the crystallization channel through the liquid inlet, completes the precipitation process, and is discharged from the gradual expansion pipe 12 after passing through the first anti-solvent jacket pipe 7 and the second anti-solvent jacket pipe 11, and is stored in the buffer tank. The potassium bicarbonate crystals are obtained by filtration, the particle size range is 10 μm-23 μm, and d50=17 μm.

[0081] Example 3: Sodium chloride powder was prepared by using the anti-solvent crystallizer. The anti-solvent was anhydrous ethanol and the raw material liquid was sodium chloride solution. Sodium chloride was insoluble in anhydrous ethanol, but water and anhydrous ethanol were mutually soluble, and sodium chloride crystals were precipitated. The inlet diameter of the tapered pipe 1 was 74 mm, the inner diameter of the crystallization channel was 24 mm, the annular gap was 2 mm, the first dispersion hole 16 (using tangential dispersion hole 16-1) and the third dispersion hole 18, the pore size was 2 mm, and the additional raw material liquid was not required to be fed. The anti-solvent flow rate of the inlet of the tapered pipe 1 was 300 L / h, the anti-solvent flow rate of the first anti-solvent feeding pipe 6 and the second anti-solvent feeding pipe 10 was 70 L / h, and the anti-solvent was fed first at the beginning of crystallization, and the internal flow was stable. The flow rate of the raw material liquid was 30 L / h, which entered the annular gap from the raw material liquid feeding pipe 3, then entered the crystallization channel through the liquid inlet, completed the precipitation process, and then the mixed fluid passed through the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11, and then was discharged from the gradually expanding pipe 12 and stored in the buffer tank. The spherical sodium chloride crystals were obtained by filtration, the particle size range was 9 μm-15 μm, and d50=12 μm. Subsequently, 3 L / h of raw material liquid was supplemented by the additional raw material liquid feeding pipe 8, which entered the crystallization channel through the second dispersion hole 17, completed the precipitation process, and then the mixed fluid passed through the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11, and then was discharged from the gradually expanding pipe 12 and stored in the buffer tank. The spherical sodium chloride crystals were obtained by filtration, the particle size range was 12 μm-22 μm, and d50=17 μm.

[0082] The application also provides a crystallization method using the anti-solvent crystallizer as described above, comprising:

[0083] (1) The raw material liquid enters the raw material liquid section through the buffer cavity of the raw material liquid feeding pipe 3, the anti-solvent enters the raw material liquid section through the annular gap of the tapered section and mixes with the raw material liquid, the crystallization channel precipitates crystals, and forms a mixed fluid;

[0084] (2) The mixed fluid enters the first anti-solvent section, the anti-solvent enters the first anti-solvent section through the buffer cavity of the first anti-solvent feeding pipe 6 and mixes with the mixed fluid, the crystallization channel precipitates crystals, and the crystals are discharged from the gradually expanding section.

[0085] The raw material liquid enters the raw material liquid section through the buffer cavity and the annular gap of the raw material liquid feeding pipe 3, the anti-solvent enters the channel of the raw material liquid section through the flow channel of the tapered section and mixes with the raw material liquid, and the precipitation process is completed. The mixed fluid enters the inner channel of the first anti-solvent section, mixes with the anti-solvent fed through the buffer cavity of the first anti-solvent feeding pipe 6, further increases the solute supersaturation, and the internal solvent of the precipitated crystals is precipitated, and then the crystals are discharged from the gradually expanding section.

[0086] The crystallization method using the anti-solvent crystallizer, the buffer cavity provides buffering effect for the raw material liquid and the anti-solvent entering the crystallization channel; the anti-solvent enters the crystallization channel from the tapered section and the first anti-solvent section respectively, by setting multiple anti-solvent feeding, a controllable solute supersaturation gradient can be formed in the crystallization channel; the annular gap is conducive to the anti-solvent fluid shearing the raw material liquid, so that the raw material liquid entering the clean channel is in a dispersed phase, the raw material liquid and the anti-solvent can be fully mixed in a short time, the mixing between the fluids in the channel is strengthened, and then a product with controllable crystal size and shape is obtained.

[0087] By using multi-stage anti-solvent feeding, the anti-solvent can be fed by suction, and a pumping system is no longer needed. Optionally, the crystallizer body further comprises at least one second anti-solvent section, and at least one second anti-solvent feeding pipe 10 is arranged on the crystallizer body. Step (2) further comprises: the mixed fluid in the first anti-solvent section enters the second anti-solvent section, the anti-solvent enters the second anti-solvent section from the second anti-solvent feeding pipe 10 and mixes with the mixed fluid, and the crystallization channel precipitates crystals.

[0088] By using the supplementary raw material liquid feeding mode, the crystallization shaping can be adjusted. Optionally, at least one supplementary raw material feeding pipe 8 is arranged on the crystallizer body. Step (2) further comprises: the supplementary raw material feeding pipe 8 supplements the raw material liquid to the crystallization channel through the first anti-solvent section or the second anti-solvent section.

[0089] In order to realize a smooth crystallization process and produce crystals with different shapes and particle sizes, optionally, the crystallizer body comprises a tapered pipe 1, a first shell 14, a second shell 5, a third shell 9 and a gradual expansion pipe 12 connected in sequence; a raw material liquid jacket pipe 4, a first anti-solvent jacket pipe 7 and a second anti-solvent jacket pipe 11 are arranged in the first shell 14, the second shell 5 and the third shell 9 in sequence;

[0090] Step (1) comprises: the raw material liquid enters the raw material liquid jacket pipe 4 from the raw material liquid feeding pipe 3, and the anti-solvent enters the raw material liquid jacket pipe 4 from the tapered pipe 1 and mixes with the raw material liquid;

[0091] Step (2) comprises: the mixed fluid enters the first anti-solvent jacket pipe 7, the anti-solvent enters the first anti-solvent jacket pipe 7 from the first anti-solvent feeding pipe 6 and mixes with the mixed fluid, the crystallization channel precipitates crystals, and the mixed fluid with increased concentration is formed; the supplementary raw material feeding pipe 8 supplements the raw material liquid to the crystallization channel through the first anti-solvent jacket pipe 7 or the second anti-solvent jacket pipe 11; the mixed fluid with increased concentration and the supplementary raw material liquid enter the second anti-solvent jacket pipe 11, the anti-solvent enters the second anti-solvent jacket pipe 11 from the second anti-solvent feeding pipe 10 and mixes with the mixed fluid with increased concentration and the supplementary raw material liquid, and the crystallization channel precipitates crystals.

[0092] In one embodiment of the present application, the raw material liquid enters the raw material liquid jacket 4 from the raw material liquid feed pipe 3, the anti-solvent enters the passage of the raw material liquid jacket 4 from the flow channel of the tapered pipe 1 to mix with the raw material liquid, and the precipitation process is completed; the mixed fluid enters the passage of the first anti-solvent jacket 7, mixes with the anti-solvent entering from the first dispersion hole 16, and further increases the solute supersaturation, so that the solvent in the crystal obtained by precipitation is further precipitated; the mixed fluid enters the second anti-solvent jacket 11 along the axial direction, mixes with the anti-solvent entering from the second dispersion hole 17, and further increases the solute supersaturation, so that the solvent wrapped by the crystal is completely precipitated.

[0093] In order to simplify the structure, the Venturi structure is used to provide the buffering effect through the first buffer cavity to ensure stable feeding. Optionally, the buffer cavity includes a first buffer cavity arranged in the first shell 14, the raw material liquid jacket 4 is at least partially arranged in the first buffer cavity, at least one feed hole 2 is arranged on the raw material liquid jacket 4, a circumferential gap is arranged between the raw material liquid jacket 4 and the tapered pipe 1, and the raw material liquid feed pipe 3 is arranged on the first shell 14; step (1) further includes: the raw material liquid enters the crystallization passage in sequence through the raw material liquid feed pipe 3, the first buffer cavity, the feed hole 2, and the circumferential gap.

[0094] In order to simplify the structure, the Venturi structure is used to provide the buffering effect through the second buffer cavity to ensure stable feeding. Optionally, the buffer cavity includes a second buffer cavity arranged in the second shell 5, the first anti-solvent jacket 7 is at least partially arranged in the second buffer cavity, at least one first dispersion hole 16 is arranged on the first anti-solvent jacket 7, and the first anti-solvent feed pipe 6 is arranged on the second shell 5; step (2) further includes: the anti-solvent enters the crystallization passage in sequence through the first anti-solvent feed pipe 6, the second buffer cavity, and the first dispersion hole 16.

[0095] In order to simplify the structure, the Venturi structure is used to provide the buffering effect through the third buffer cavity to ensure stable feeding. Optionally, the buffer cavity includes a third buffer cavity arranged in the third shell 9, the first anti-solvent jacket 7 is at least partially arranged in the third buffer cavity, at least one second dispersion hole 17 is arranged on the first anti-solvent jacket 7, and the supplemental raw material feed pipe 8 is arranged on the third shell 9; step (2) further includes: the supplemental raw material liquid enters the crystallization passage in sequence through the supplemental raw material feed pipe 8, the third buffer cavity, and the second dispersion hole 17.

[0096] In order to simplify the structure, the suction effect of the Venturi structure is utilized, the buffering effect is provided through the fourth buffer cavity, and stable feeding is ensured. Optionally, the buffer cavity comprises a fourth buffer cavity arranged in the third shell 9, the second anti-solvent sleeve 11 is arranged at least partially in the fourth buffer cavity, at least one third dispersion hole 18 is arranged on the second anti-solvent sleeve 11, and the second anti-solvent sleeve 11 is arranged on the third shell 9; and the step (2) further comprises: the anti-solvent enters the crystallization channel in sequence through the second anti-solvent sleeve 11, the fourth buffer cavity, and the third dispersion hole 18.

[0097] In order to obtain crystals with different shapes and particle sizes, optionally, the step (2) further comprises: adjusting the relative feeding rate of the raw material liquid and the anti-solvent to change the crystal shape and particle size; relatively increasing the anti-solvent feeding rate is helpful to form fiber-shaped precipitated crystals; and relatively increasing the raw material liquid feeding speed is helpful to form spherical precipitated crystals.

[0098] And / or adjusting the feeding flow type of the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11 to change the crystal shape and particle size. The first anti-solvent sleeve 7 can provide two feeding modes of radial feeding and tangential feeding, and the second anti-solvent sleeve 11 can provide tangential feeding. The first anti-solvent sleeve 7 with the first dispersion hole 16 as the radial feeding direction and the second anti-solvent sleeve 11 are fed, which is helpful to form fiber-shaped precipitated crystals; and the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11 with the second dispersion hole 17 as the tangential feeding direction are fed, which is helpful to form spherical precipitated crystals.

[0099] In order to obtain fiber-shaped precipitated crystals, optionally, the step (2) further comprises: increasing the feeding rate of at least one of the tapered pipe 1, the first anti-solvent feeding pipe 6, and the second anti-solvent sleeve 11, and / or reducing the feeding rate of the raw material liquid feeding pipe 3; and feeding the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11 with the first dispersion hole 16 as the radial feeding direction to obtain fiber-shaped precipitated crystals.

[0100] In an embodiment of the present application, without changing the feeding rate of the raw material liquid feeding pipe 3, the feeding rates of the tapered pipe 1, the first anti-solvent feeding pipe 6, and the second anti-solvent sleeve 11 are increased, the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11 are fed with the first dispersion hole 16 as the radial feeding direction, and the raw material liquid feeding pipe 3 provides the raw material liquid to obtain fiber-shaped precipitated crystals.

[0101] In order to obtain spherical precipitated crystals, optionally, the step (2) further comprises: reducing the feeding rate of at least one of the tapered pipe 1, the first anti-solvent feeding pipe 6, and the second anti-solvent sleeve 11, and / or increasing the feeding rate of the raw material liquid feeding pipe 3; and feeding the first anti-solvent sleeve 7 and the second anti-solvent sleeve 11 with the second dispersion hole 17 as the tangential feeding direction, and the supplementary raw material feeding pipe 8 provides supplementary raw material liquid to obtain spherical precipitated crystals.

[0102] In one embodiment of the present application, the feed rate of the raw material liquid feed pipe 3 is not changed, while the feed rate of the tapered pipe 1, the first anti-solvent feed pipe 6 and the second anti-solvent jacket pipe 11 is reduced, the first anti-solvent jacket pipe 7 and the second anti-solvent jacket pipe 11 are fed with the second dispersion hole 17 in the tangential direction, the raw material liquid feed pipe 3 provides the raw material liquid, and the make-up raw material feed pipe 8 provides the make-up raw material liquid, so as to obtain spherical precipitated crystals.

[0103] From the above description and practice, the anti-solvent crystallizer and the crystallization method provided by the present application have the following advantages compared with the prior art: the above-mentioned anti-solvent crystallizer provides a buffering effect for the raw material liquid and the anti-solvent entering the crystallization channel; the anti-solvent enters the crystallization channel from the tapered section and the first anti-solvent section respectively, and a controllable solute supersaturation gradient can be formed in the crystallization channel by setting multiple anti-solvent entering; the annular gap is conducive to the shearing of the raw material liquid by the anti-solvent fluid, so that the raw material liquid entering the clean channel is in a dispersed phase, the raw material liquid and the anti-solvent can be fully mixed in a short time, the mixing between the fluids in the channel is strengthened, and then the product with controllable crystal size and shape is obtained.

[0104] Those skilled in the art should understand that the above description is only a specific embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit of the present application should be included in the protection scope of the present application.

Claims

1. An anti-solvent crystallizer characterized by, The anti-solvent crystallizer comprises a crystallizer body, wherein the crystallizer body comprises a tapering section, a raw material liquid section, a first anti-solvent section and a diverging section which are sequentially communicated, and flow channels of the tapering section, the raw material liquid section, the first anti-solvent section and the diverging section form a crystallization channel; an annular gap is arranged between the tapering section and the raw material liquid section, the raw material liquid section and the first anti-solvent section each have a buffer cavity between the inner wall of the crystallizer body, and the crystallizer body is provided with a raw material liquid feeding pipe and a first anti-solvent feeding pipe at intervals, and the raw material liquid feeding pipe and the first anti-solvent feeding pipe are respectively communicated with the raw material liquid section and the first anti-solvent section through the buffer cavity.

2. The anti-solvent crystallizer according to claim 1, wherein: the crystallizer body further comprises at least one second anti-solvent section, the second anti-solvent section is communicated between the first anti-solvent section and the diverging section, the flow channel of the second anti-solvent section is communicated with the crystallization channel, the second anti-solvent section has the buffer cavity between the inner wall of the crystallizer body, and the crystallizer body is provided with at least one second anti-solvent feeding pipe, and the second anti-solvent feeding pipe is communicated with the second anti-solvent section through the buffer cavity.

3. The anti-solvent crystallizer according to claim 2, wherein: the crystallizer body is provided with at least one supplementary raw material liquid feeding pipe, and the supplementary raw material liquid feeding pipe is communicated with the crystallization channel through the first anti-solvent section or the second anti-solvent section.

4. The anti-solvent crystallizer according to claim 3, wherein: the crystallizer body comprises a tapering pipe, a first shell, a second shell, a third shell and a diverging pipe which are sequentially connected, and the first shell, the second shell and the third shell are sequentially provided with a raw material liquid sleeve pipe, a first anti-solvent sleeve pipe and a second anti-solvent sleeve pipe; the tapering pipe and the diverging pipe respectively form the tapering section and the diverging section; the first shell and the raw material liquid sleeve pipe form the raw material liquid section; the second shell and the first anti-solvent feeding pipe form the first anti-solvent section; the third shell and the second anti-solvent feeding pipe form the second anti-solvent section; the raw material liquid feeding pipe, the first anti-solvent feeding pipe, the supplementary raw material liquid feeding pipe and the second anti-solvent feeding pipe are respectively arranged on at least one of the first shell, the second shell and the third shell.

5. The anti-solvent crystallizer according to claim 4, wherein: the buffer cavity comprises a first buffer cavity arranged in the first shell, the raw material liquid sleeve pipe is at least partially arranged in the first buffer cavity, at least one feeding hole is arranged on the raw material liquid sleeve pipe, an annular gap is arranged between the raw material liquid sleeve pipe and the tapering pipe, and the raw material liquid feeding pipe is arranged on the first shell, and the raw material liquid feeding pipe is communicated with the crystallization channel through the first buffer cavity, the feeding hole and the annular gap.

6. The anti-solvent crystallizer according to claim 5, wherein: ​ ​ ​ ​ ​ The inlet end of the raw material liquid jacket pipe comprises a connecting pipe section and an inlet pipe section connected in sequence, the connecting pipe section is sleeved outside the tapered pipe, the annular gap is formed between the connecting pipe section and the tapered pipe, and the feed hole is arranged on the connecting pipe section; the inner diameter of the inlet pipe section is smaller than the inner diameter of the tapered pipe.

7. The anti-solvent crystallizer of claim 5 or 6, wherein: The raw material liquid jacket pipe is provided with a plurality of protrusions distributed along the axial direction, and the protrusions are used to reduce the passage area of the raw material liquid jacket pipe.

8. The anti-solvent crystallizer of claim 7, wherein: The buffer cavity comprises a second buffer cavity arranged in the second shell, the first anti-solvent jacket pipe is at least partially arranged in the second buffer cavity, at least one first dispersion hole is arranged on the first anti-solvent jacket pipe, the first anti-solvent feeding pipe is arranged on the second shell, and the first anti-solvent feeding pipe communicates with the crystallization channel through the second buffer cavity and the first dispersion hole.

9. The anti-solvent crystallizer of claim 8, wherein: The buffer cavity comprises a third buffer cavity arranged in the third shell, the first anti-solvent jacket pipe is at least partially arranged in the third buffer cavity, at least one second dispersion hole is arranged on the first anti-solvent jacket pipe, the supplementary raw material liquid feeding pipe is arranged on the third shell, and the supplementary raw material liquid feeding pipe communicates with the crystallization channel through the third buffer cavity and the second dispersion hole.

10. The anti-solvent crystallizer of claim 9, wherein: The buffer cavity comprises a fourth buffer cavity arranged in the third shell, the second anti-solvent jacket pipe is at least partially arranged in the fourth buffer cavity, at least one third dispersion hole is arranged on the second anti-solvent jacket pipe, the second anti-solvent jacket pipe is arranged on the third shell, and the second anti-solvent jacket pipe communicates with the crystallization channel through the fourth buffer cavity and the third dispersion hole.

11. The anti-solvent crystallizer of claim 10, wherein: At least one guide plate is arranged in the second anti-solvent jacket pipe.

12. A crystallization method using the anti-solvent crystallizer according to any one of claims 1 to 11, characterized by, Comprise: (1) The raw material liquid enters the raw material liquid section through the buffer cavity from the raw material liquid feeding pipe, the anti-solvent enters the raw material liquid section through the annular gap from the tapered section, mixes with the raw material liquid, the crystallization channel precipitates crystals, and forms a mixed fluid; (2) The mixed fluid enters the first anti-solvent section, the anti-solvent enters the first anti-solvent section through the buffer cavity from the first anti-solvent feeding pipe, mixes with the mixed fluid, the crystallization channel precipitates crystals, and the crystals are discharged from the expanding section.

13. The crystallization method of the anti-solvent crystallizer of claim 12, wherein: The crystallizer body further comprises at least one second anti-solvent section, at least one second anti-solvent feeding pipe is arranged on the crystallizer body, and step (2) further comprises: the mixed fluid in the first anti-solvent section enters the second anti-solvent section, the anti-solvent enters the second anti-solvent section through the buffer cavity from the second anti-solvent feeding pipe, mixes with the mixed fluid, and the crystallization channel precipitates crystals.

14. The crystallization method of the anti-solvent crystallizer according to claim 13, wherein: the crystallizer body is provided with at least one additional raw material liquid feeding pipe, and step (2) further comprises that the additional raw material liquid feeding pipe supplies raw material liquid to the crystallization channel through the first anti-solvent section or the second anti-solvent section.

15. The crystallization method of the anti-solvent crystallizer according to claim 14, wherein: the crystallizer body comprises a converging pipe, a first shell, a second shell, a third shell and a diverging pipe connected in sequence, and the first shell, the second shell and the third shell are provided with a raw material liquid jacket pipe, a first anti-solvent jacket pipe and a second anti-solvent jacket pipe in sequence; step (1) comprises that raw material liquid enters the raw material liquid jacket pipe from the raw material liquid feeding pipe, and anti-solvent enters the raw material liquid jacket pipe from the converging pipe to mix with the raw material liquid; step (2) comprises that the mixed fluid enters the first anti-solvent jacket pipe, anti-solvent enters the first anti-solvent jacket pipe from the first anti-solvent feeding pipe to mix with the mixed fluid, crystals are precipitated in the crystallization channel, and mixed fluid with increased concentration is formed; the additional raw material liquid feeding pipe supplies raw material liquid to the crystallization channel through the first anti-solvent jacket pipe or the second anti-solvent jacket pipe; mixed fluid with increased concentration and additional raw material liquid enter the second anti-solvent jacket pipe, anti-solvent enters the second anti-solvent jacket pipe from the second anti-solvent feeding pipe to mix with the mixed fluid with increased concentration and the additional raw material liquid, and crystals are precipitated in the crystallization channel.

16. The crystallization method of the anti-solvent crystallizer according to claim 15, wherein: the buffer cavity comprises a first buffer cavity provided in the first shell, the raw material liquid jacket pipe is at least partially provided in the first buffer cavity, the raw material liquid jacket pipe is provided with at least one feeding hole, a circumferential gap is provided between the raw material liquid jacket pipe and the converging pipe, and the raw material liquid feeding pipe is provided on the first shell; and step (1) further comprises that raw material liquid enters the crystallization channel in sequence through the raw material liquid feeding pipe, the first buffer cavity, the feeding hole and the circumferential gap.

17. The crystallization method of the anti-solvent crystallizer according to claim 16, wherein: the buffer cavity comprises a second buffer cavity provided in the second shell, the first anti-solvent jacket pipe is at least partially provided in the second buffer cavity, the first anti-solvent jacket pipe is provided with at least one first dispersion hole, and the first anti-solvent feeding pipe is provided on the second shell; and step (2) further comprises that anti-solvent enters the crystallization channel in sequence through the first anti-solvent feeding pipe, the second buffer cavity and the first dispersion hole.

18. The crystallization method of the anti-solvent crystallizer according to claim 17, wherein: ​ ​ ​ ​ The buffer cavity comprises a third buffer cavity arranged in a third shell, the first anti-solvent sleeve is at least partially arranged in the third buffer cavity, at least one second dispersion hole is arranged on the first anti-solvent sleeve, and the supplementary raw material liquid feeding pipe is arranged on the third shell; step (2) further comprises: the supplementary raw material liquid enters the crystallization channel in sequence through the supplementary raw material liquid feeding pipe, the third buffer cavity and the second dispersion hole.

19. The crystallization method of the anti-solvent crystallizer according to claim 18, wherein: The buffer cavity comprises a fourth buffer cavity arranged in a third shell, the second anti-solvent sleeve is at least partially arranged in the fourth buffer cavity, at least one third dispersion hole is arranged on the second anti-solvent sleeve, and the second anti-solvent sleeve is arranged on the third shell; step (2) further comprises: the anti-solvent enters the crystallization channel in sequence through the second anti-solvent sleeve, the fourth buffer cavity and the third dispersion hole.

20. The crystallization method of the anti-solvent crystallizer according to claim 19, wherein: Step (2) further comprises: changing the crystal shape and particle size by adjusting the relative feeding rate of the raw material liquid and the anti-solvent; and / or changing the crystal shape and particle size by adjusting the feeding flow type of the first anti-solvent sleeve and the second anti-solvent sleeve.

21. The crystallization method of the anti-solvent crystallizer according to claim 20, wherein: Step (2) further comprises: increasing the feeding rate of at least one of the tapered pipe, the first anti-solvent feeding pipe and the second anti-solvent sleeve, and / or reducing the feeding rate of the raw material liquid feeding pipe; and feeding the first anti-solvent sleeve and the second anti-solvent sleeve with the first dispersion hole in the radial feeding direction to obtain fibrous precipitated crystals.

22. The crystallization method of the anti-solvent crystallizer according to claim 21, wherein: Step (2) further comprises: reducing the feeding rate of at least one of the tapered pipe, the first anti-solvent feeding pipe and the second anti-solvent sleeve, and / or increasing the feeding rate of the raw material liquid feeding pipe; and feeding the first anti-solvent sleeve and the second anti-solvent sleeve with the second dispersion hole in the tangential feeding direction, and the supplementary raw material liquid feeding pipe provides supplementary raw material liquid to obtain spherical precipitated crystals.

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