A regulating valve and a continuous crystallization system comprising the same

Abstract

The present application relates to a kind of regulating valve and the continuous crystallization system comprising the regulating valve, regulating valve includes valve body and the piston assembly that can reciprocate in valve body inside, valve body has mutually interconnected main channel, first shunt channel and second shunt channel, first shunt channel has first mouth, and first shunt channel has full open operating state, piston assembly reciprocates in valve body during and make first shunt channel always be in full open operating state;Second shunt channel has second mouth, piston assembly reciprocates in valve body, and during movement, cover all or avoid second mouth, so that second shunt channel is respectively in full close or full open operating state, and in the adjustment process of second shunt channel in full close and full open operating state, first shunt channel always be in full open operating state, so that the flow area of first shunt channel is unchanged, guarantee the communication between main channel and first shunt channel is not affected.

Description

TECHNICAL FIELD

[0001] The present application relates to a regulating valve and a continuous crystallization system comprising the same. BACKGROUND

[0002] In a continuous process, the delivery of materials is usually to control the flow, and the simple liquid, gas delivery, the control of the flow of the valve will not appear stuck, blocked. However, when the liquid contains solid particles, the control of the flow of the valve will appear stuck, blocked, especially when the small flow is more difficult to control the flow, often because of the blockage of the pipeline flow and have to stop production to dredge.

[0003] As in the continuous crystallization production process, see Figures 1-2 The conventional continuous crystallization system mainly comprises a crystallizer 1' with a discharge port, a seed tank 2' and a discharge pipe 3' connected between the discharge port of the crystallizer 1' and the seed tank 2', a flow regulating valve and a delivery pump 4' are arranged on the discharge pipe 3', however, in the pilot scale production of continuous crystallization, because the flow rate of the crystalline slurry in the discharge pipe 3' is low, the pipe diameter of the discharge pipe 3' is also small, the flow regulating valve is often stuck, blocked; and if the pipe diameter of the discharge pipe 3' is enlarged, the flow rate of the crystalline slurry is low, and the crystalline particles are easily settled in the discharge pipe 3' to block the discharge pipe.

[0004] In the traditional continuous crystallization production process, the risk of pipeline and valve blockage is mainly reduced by the following two methods:

[0005] The first method: see Figure 1 The flow is adjusted by using a return pipe 5' connected between the discharge pipe 3' and the crystallizer 1', the pipe section of the discharge pipe 3' between the connection of the return pipe 5' and the discharge pipe 3' and the connection of the discharge pipe 3' and the seed tank 2' is used as the production pipe section 3a', and the flow regulating valves 6' are arranged on the return pipe 5' and the production pipe section 3a', although the risk of pipeline blockage can be reduced to a certain extent, however, when the flow rate of the crystalline slurry in the production pipe section 3a' is low, the flow regulating valves 6' on the return pipe 5' and the production pipe section 3a' are still prone to blockage.

[0006] The second method: see Figure 2 The flow of the crystalline slurry is controlled by changing the rotation frequency of the motor of the delivery pump 4', the pipe section of the discharge pipe 3' between the delivery pump 4' and the seed tank 2' is used as the production pipe section 3a', when the flow rate of the crystalline slurry in the production pipe section 3a' is low, the delivery pump 4' and the production pipe section 3a' still have the risk of blockage.

[0007] In summary, the existing continuous crystallization system still has the problem of pipeline or valve blockage when the flow of the crystalline slurry is low. SUMMARY

[0008] The technical problem solved by the present application is to provide a new regulating valve for solving the problem that the crystal slurry is prone to block the pipeline or valve during the conveying process at low flow rate in the prior art.

[0009] The second object of the present application is to provide a continuous crystallization system in which the crystal slurry is not prone to block the pipeline or regulating valve during the conveying process at low flow rate.

[0010] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0011] A regulating valve comprises a valve body having a main channel, a first branch channel and a second branch channel in communication with each other, and a piston assembly capable of reciprocating within the valve body.

[0012] The first branch channel has a first port communicating with the main channel, and the first branch channel has a full open working state, and the piston assembly avoids the first port during reciprocation within the valve body so that the first branch channel is always in the full open working state.

[0013] The second branch channel has a second port communicating with the main channel, and the piston assembly can cover or avoid the second port during reciprocation within the valve body, and the second branch channel has at least a full closed working state and a full open working state, when the piston assembly moves to cover the second port, the second branch channel is in the full closed working state, and the communication between the main channel and the second branch channel is blocked by the piston assembly; when the piston assembly moves to avoid the second port, the second branch channel is in the full open working state, and the main channel and the second branch channel are in communication.

[0014] According to some embodiments of the present application, the valve body further has a movement channel for reciprocation of the piston assembly and in communication with the main channel, and the first port is located on the side wall of the main channel, and the second port is located on the side wall of the movement channel.

[0015] Preferably, the length extension direction of the movement channel is consistent with the length extension direction of the main channel, and the side surface of the piston assembly facing the main channel is an arc surface. The arc surface of the piston assembly is beneficial to reduce fluid resistance and reduce the possibility of crystal deposition.

[0016] Further preferably, the radius of the arc surface is greater than or equal to the inner diameter of the main channel. Still further preferably, the radius of the arc surface is equal to the inner diameter of the main channel.

[0017] In some embodiments, the valve body comprises a straight pipe section with two open ends, a first branch pipe section and a second branch pipe section connected to opposite sides of the straight pipe section respectively, an inner portion of the straight pipe section sequentially forms the main passage and the movement passage respectively, an inner portion of the first branch pipe section forms the first shunt passage, and an inner portion of the second branch pipe section forms the second shunt passage.

[0018] In some preferred and specific embodiments, the valve body further comprises a sealing cover arranged at an end portion of the straight pipe section close to the movement passage, and an end portion of the piston assembly extends out of the valve body through the sealing cover.

[0019] In some preferred and specific embodiments, the piston assembly comprises a piston body arranged in the valve body, a connecting rod connected to an end portion of the piston body, and a piston plate connected to an opposite end portion of the connecting rod, the valve body further comprises a sealing cover arranged at an end portion of the straight pipe section close to the movement passage, and a fixing plate arranged between the piston body and the sealing cover, the connecting rod extends through the fixing plate and the piston plate is located between the fixing plate and the sealing cover, a cavity is jointly formed by the fixing plate, an inner wall of the straight pipe section, and the sealing cover, the piston plate divides the cavity into a first chamber and a second chamber which are independent of each other, the first chamber and the second chamber are respectively provided with a first interface and a second interface for connecting to a compressed air pipeline or a hydraulic oil pipeline, and the piston plate moves when the first chamber or the second chamber is filled with compressed air or hydraulic oil through the first interface or the second interface, thereby driving the piston body to move.

[0020] According to some embodiments of the present application, the piston assembly can cover part of the second port portion during reciprocating movement in the valve body, the second shunt passage has a plurality of intermediate working states between a fully closed working state and a fully open working state, and the second shunt passage is in an intermediate working state when the piston assembly moves to cover part of the second port portion, and the main passage is in communication with the second shunt passage.

[0021] According to some embodiments of the present application, an inner diameter of the second shunt passage is less than or equal to an inner diameter of the first shunt passage, and the inner diameter of the first shunt passage is less than or equal to an inner diameter of the main passage.

[0022] According to some embodiments of the present application, an inner diameter of the second shunt passage is greater than or equal to 40 mm.

[0023] According to some embodiments of the present application, the regulating valve further comprises a driving mechanism for driving the piston assembly to reciprocate.

[0024] Further, the driving mechanism is an electric driving mechanism or a pneumatic driving mechanism or a hydraulic driving mechanism.

[0025] The second technical solution of the present application is a continuous crystallization system, comprising a crystallizer and a seed tank, the crystallizer is provided with a discharge port, the discharge port is connected with a discharge pipe, the discharge pipe is connected with the crystallizer through a reflux pipe, the discharge pipe is also connected with the seed tank through a production pipe, the discharge pipe, the reflux pipe and the production pipe are provided with the regulating valve, wherein the discharge pipe is communicated with the main channel, the reflux pipe is communicated with the first branch channel, and the production pipe is communicated with the second branch channel.

[0026] According to some embodiments of the present application, the valve body is arranged above the seed tank, the extension direction of the production pipe is consistent with the extension direction of the second branch channel, and the second branch channel extends along the vertical direction or extends along the vertical direction in an inclined manner.

[0027] According to some embodiments of the present application, the continuous crystallization system further comprises a first flow meter arranged on the reflux pipe, a second flow meter arranged on the discharge pipe, a delivery pump arranged on the discharge pipe, and a frequency converter connected with the delivery pump.

[0028] According to some embodiments of the present application, the continuous crystallization system further comprises a heat exchanger, the crystallizer is further provided with a material circulation outlet and a material circulation inlet, a refrigerant inlet of the heat exchanger is connected with the material circulation outlet through a first circulation pipe, a refrigerant outlet of the heat exchanger is connected with the material circulation inlet through a second circulation pipe, and the continuous crystallization system further comprises a mother liquor delivery pipe connected with the first circulation pipe and a circulation pump arranged on the first circulation pipe.

[0029] According to some embodiments of the present application, the continuous crystallization system further comprises a first cut-off valve arranged on the reflux pipe and a second cut-off valve arranged on the discharge pipe.

[0030] According to some embodiments of the present application, the crystallizer is an OSLO evaporation crystallizer.

[0031] In the present application, the continuous crystallization system can be used for continuous crystallization production of 4-chloro-3,5-dimethylphenol crystals.

[0032] The method for using the continuous crystallization system comprises adjusting the position of the piston assembly in the valve body according to the production amount of the production pipe, so that the second branch channel is in different working states.

[0033] When the production amount of the production pipe is less than a certain amount, the piston assembly is made to do pulse reciprocating motion, and then the piston assembly is made to pulse switch between covering all the second port and avoiding the second port; when the production amount of the production pipe is greater than the certain amount, the piston assembly is made to move to avoid the second port or cover part of the second port, and the second shunt channel is in a fully open working state or an intermediate working state.

[0034] According to some embodiments of the present application, the certain amount can be adjusted according to actual working conditions, such as the certain amount being 2-3 m 3 / h.

[0035] According to some embodiments of the present application, the use method further comprises making the flow of the material in the return pipe greater than or equal to 5 m 3 / h.

[0036] The continuous crystallization system can be used for continuous crystallization production of 4-chloro-3,5-dimethylphenol (PCMX) crystals.

[0037] The third technical solution adopted by the present application is the application of the above-mentioned regulating valve in the conveying of solid-liquid mixed materials.

[0038] According to some embodiments of the present application, the regulating valve is applied in the conveying of 4-chloro-3,5-dimethylphenol crystal slurry.

[0039] Due to the use of the above technical solutions, the present application has the following advantages compared with the prior art:

[0040] The regulating valve of the present application makes the piston assembly do reciprocating motion in the valve body, and covers all or avoids the second port of the second shunt channel during the motion process, so that the second shunt channel is respectively in a fully closed working state or a fully open working state, and during the adjustment process of the second shunt channel in the fully closed working state and the fully open working state, the first shunt channel is always in a fully open working state, so that the flow area of the first shunt channel is unchanged, and the flow between the main channel and the first shunt channel is not affected. When this regulating valve is used in a continuous crystallization system, even if the crystal slurry in the production pipe is in a low flow condition, the first shunt channel is always in a fully open working state, and the flow of the material in the return pipe is still not affected, avoiding the blockage of the return pipe, and the second shunt channel can be pulse opened and closed, ensuring the production of the crystal slurry and avoiding the blockage of the regulating valve, so that the continuous production of crystallization can be smoothly carried out without stopping the production to dredge the pipeline or valve. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The structure diagram of the continuous crystallization system of the traditional first method;

[0042] Figure 2 Structure diagram of a continuous crystallization system according to the second method of the prior art;

[0043] Figures 1-2 In the figure: 1', crystallizer; 2', crystallization tank; 3', discharge pipe; 3a', production pipe section; 4', delivery pump; 5', return pipe; 6', flow regulating valve.

[0044] Figure 3 Structure diagram of a continuous crystallization system according to an embodiment of the present application;

[0045] Figure 4 Structure diagram of a continuous crystallization system according to the second method of the prior art; Figure 3 Structure diagram of a flow regulating valve of a continuous crystallization system according to the second method of the prior art (second branch channel in full-closed working state);

[0046] Figure 5 Structure diagram of a flow regulating valve of a continuous crystallization system according to the second method of the prior art (second branch channel in intermediate working state); Figure 3 Structure diagram of a flow regulating valve of a continuous crystallization system according to the second method of the prior art (second branch channel in full-open working state);

[0047] Figure 6 Structure diagram of a flow regulating valve of a continuous crystallization system according to the second method of the prior art (second branch channel in full-open working state); Figure 3

[0048] Structure diagram of a flow regulating valve of a continuous crystallization system according to another embodiment of the present application; Figure 7

[0049] In the figure: 1, crystallizer; 2, crystallization tank; 3, discharge pipe; 4, delivery pump; 5, return pipe; 6, production pipe; 7, flow regulating valve; Figures 3-7 7a, valve body; 7a1, straight pipe section; 7a2, first branch pipe section; 7a3, second branch pipe section; 7a4, sealing cover; 7a5, fixing plate; 7a6, first interface; 7a7, second interface; 7b, main channel; 7c, first branch channel; 7d, second branch channel; 7e, piston assembly; 7e1, piston body; 7e2, arc surface; 7e3, connecting rod; 7e4, piston plate; 7f, movement channel;

[0050] 8, first flow meter; 9, second flow meter; 10, frequency converter; 11, first shut-off valve; 12, second shut-off valve; 13, heat exchanger; 14, first circulation pipe; 15, second circulation pipe; 16, circulation pump; 17, mother liquor delivery pipe.

[0051] DETAILED DESCRIPTION

[0052] ​The present application effectively solves the problem of pipeline or regulating valve blockage in the process of transporting the crystal slurry at low flow rate by redesigning the structure of the regulating valve and applying it to the continuous crystallization system, and the continuous crystallization production can be carried out smoothly without stopping the production to dredge the pipeline or valve.

[0053] One preferred and specific embodiment is as follows:

[0054] Referring to Figures 3-6 , the structure of the continuous crystallization system adopted comprises a crystallizer 1 and a seed tank 2, the crystallizer 1 has a discharge port, the discharge port is connected with a discharge pipe 3, the discharge pipe 3 is connected with the crystallizer 1 through a reflux pipe 5, the discharge pipe 3 is also connected with the seed tank 2 through a production pipe 6, and a regulating valve 7 is arranged between the discharge pipe 3, the reflux pipe 5 and the production pipe 6.

[0055] Referring to Figures 4-6 , the regulating valve 7 comprises a valve body 7a, the valve body 7a has a main passage 7b, a first shunt passage 7c and a second shunt passage 7d which are in communication with each other, the main passage 7b is in communication with the discharge pipe 3, the first shunt passage 7c is in communication with the reflux pipe 5, and the second shunt passage 7d is in communication with the production pipe 6.

[0056] The regulating valve 7 further comprises a piston assembly 7e which can reciprocate in the valve body 7a, the first shunt passage 7c has a first port which is in communication with the main passage 7b, and the first shunt passage 7c has a full open working state, the piston assembly 7e reciprocates in the valve body 7a and always avoids the first port so that the first shunt passage 7c is always in the full open working state; the second shunt passage 7d has a second port which is in communication with the main passage 7b, and the piston assembly 7e can cover all the second port, cover part of the second port or avoid the second port during reciprocation in the valve body 7a, the second shunt passage 7d has at least a full closed working state, a full open working state and a plurality of intermediate working states between the full closed working state and the full open working state, when the piston assembly 7e moves to cover all the second port, the second shunt passage 7d is in the full closed working state, and the communication between the main passage 7b and the second shunt passage 7d is blocked by the piston assembly 7e; when the piston assembly 7e moves to cover part of the second port, the second shunt passage 7d is in the intermediate working state, and the main passage 7b is in communication with the second shunt passage 7d; when the piston assembly 7e moves to avoid the second port, the second shunt passage 7d is in the full open working state, and the main passage 7b is in communication with the second shunt passage 7d.

[0057] The valve body 7a further has a movement passage 7f for reciprocation of the piston assembly 7e and in communication with the main passage 7b, and the first port is located on the side wall of the main passage 7b, and the second port is located on the side wall of the movement passage 7f.

[0058] Specifically, the valve body 7a comprises a straight pipe section 7a1 with two open ends, a first branch pipe section 7a2 and a second branch pipe section 7a3 connected to opposite sides of the straight pipe section 7a1, respectively, the interior of the straight pipe section 7a1 forms a main passage 7b and a movement passage 7f in sequence, the interior of the first branch pipe section 7a2 forms a first shunt passage 7c, the interior of the second branch pipe section 7a3 forms a second shunt passage 7d, the inner diameters of the main passage 7b and the movement passage 7f are consistent, one end of the straight pipe section 7a1 close to the main passage 7b is connected to the discharge pipe 3, the first branch pipe section 7a2 is connected to the return pipe 5, the second branch pipe section 7a3 is connected to the production pipe 6, and the second branch pipe section 7a3 is consistent with the extension direction of the production pipe 6, the inner diameter of the straight pipe section 7a1 is equal to the inner diameter of the discharge pipe 3, the inner diameter of the first branch pipe section 7a2 is equal to the inner diameter of the return pipe 5, and the inner diameter of the second branch pipe section 7a3 is equal to the inner diameter of the production pipe 6.

[0059] In this example, the piston assembly 7e comprises a piston body 7e1 arranged in the straight pipe section 7a1 and a connecting rod 7e3 connected to one end of the piston body 7e1, and the valve body 7a further comprises a sealing cover 7a4 arranged at one end of the straight pipe section 7a1 close to the movement passage 7f, the other end of the connecting rod 7e3 extends out of the valve body 7a through the sealing cover 7a4, the side of the piston body 7e1 facing the main passage 7b is an arc surface 7e2, the radius of the arc surface 7e2 is greater than or equal to the inner diameter of the main passage 7b, and the design of the arc surface 7e2 can reduce fluid resistance and the possibility of crystal deposition. The regulating valve 7 further comprises a driving mechanism for driving the piston assembly 7e to reciprocate in the movement passage 7f, the driving mechanism adopts a gas cylinder, the piston rod of the gas cylinder is connected to the other end of the connecting rod 7e3, and the driving mechanism drives the piston body 7e1 to reciprocate in the movement passage 7f.

[0060] In other embodiments, referring to Figure 7 the piston assembly 7e comprises a piston body 7e1 arranged in the straight pipe section 7a1, a connecting rod 7e3 connected to one end of the piston body 7e1, and a piston plate 7e4 connected to the other end of the connecting rod 7e3, and the valve body 7a further comprises a sealing cover 7a4 arranged at one end of the straight pipe section 7a1 close to the movement passage 7f and a fixed plate 7a5 arranged between the piston body 7e1 and the sealing cover 7a4, the connecting rod 7e3 is arranged through the fixed plate 7a5 and the piston plate 7e4 is located between the fixed plate 7a5 and the sealing cover 7a4, a cavity is jointly formed between the fixed plate 7a5, the inner wall of the straight pipe section 7a1 and the sealing cover 7a4, the piston plate 7e4 divides the cavity into a first chamber and a second chamber independent of each other, the first chamber and the second chamber are respectively provided with a first interface 7a6 and a second interface 7a7, the first interface 7a6 and the second interface 7a7 are respectively communicated with a compressed air pipeline, and the piston plate 7e4 is driven to move by introducing compressed air into the first chamber or the second chamber, thereby driving the reciprocating movement of the piston body 7e1.

[0061] In the specific design, the inner diameter of the second shunt passage 7d is less than or equal to the inner diameter of the first shunt passage 7c, the inner diameter of the first shunt passage 7c is equal to the inner diameter of the main passage 7b, and preferably, the inner diameter of the second shunt passage 7d is greater than or equal to 40 mm.

[0062] Referring to Figure 3 As shown, the valve body 7a of the regulating valve 7 is arranged above the crystallization tank 2, and the tapping pipe 6 and the second branch pipe portion 7a3 extend in the vertical direction, so that the crystals can smoothly fall into the crystallization tank 2 without being deposited.

[0063] The continuous crystallization system further comprises a first flow meter 8 and a first shut-off valve 11 arranged on the reflux pipe 5 respectively, a second flow meter 9, a second shut-off valve 12 and a delivery pump 4 arranged on the discharge pipe 3 respectively, and a frequency converter 10 connected with the delivery pump 4. The frequency converter 10 is used to control the rotating speed of the delivery pump 4, so as to change the delivery flow rate of the material in the discharge pipe 3, and the second flow meter 9 is located between the delivery pump 4 and the regulating valve 7.

[0064] The continuous crystallization system further comprises a heat exchanger 13, and the crystallizer 1 is an OSLO evaporation crystallizer. The crystallizer 1 further has a material circulation outlet and a material circulation inlet. The coolant inlet of the heat exchanger 13 is connected with the material circulation outlet through a first circulation pipe 14, and the coolant outlet of the heat exchanger 13 is connected with the material circulation inlet through a second circulation pipe 15. The continuous crystallization system further comprises a mother liquor delivery pipe 17 connected with the first circulation pipe 14 and a circulation pump 16 arranged on the first circulation pipe 14.

[0065] In some specific embodiments, the pipe diameter of the reflux pipe 5 is greater than or equal to 40 mm, and the pipe diameter of the tapping pipe 6 is greater than or equal to 40 mm.

[0066] Through the above-mentioned continuous crystallization system, the flow rate can be adjusted according to different working conditions, so that the crystallization slurry is not prone to block the pipeline or the valve during the delivery process even at a low flow rate.

[0067] Specifically, according to the different flow rates of the crystallization slurry in the tapping pipe 6, the position of the piston assembly 7e in the valve body 7a can be adjusted, so that the second shunt passage 7d is in different working states.

[0068] In the specific use of the above-mentioned continuous crystallization system, different working conditions are considered, such as a working condition with large production capacity, large tapping amount, large pipe diameter and large flow rate. For example, the pipe diameter of the reflux pipe 5 is 65 mm, and the pipe diameter of the tapping pipe 6 is 50 mm, so that the flow rate in the reflux pipe 5 is usually greater than 1.5 m / s, and the flow rate in the tapping pipe 6 is greater than 1 m / s (the flow rate of the tapping pipe 6 is greater than 7 m 3 / h), the speed of the delivery pump 4 is adjusted by the frequency converter 10 to control the flow rate through the second flow meter 9. Under this condition, the output is large. The position of the piston assembly 7e in the straight pipe section 7a1 is adjusted to ensure that the second diversion channel 7d is in a fully open working state or in an intermediate working state, so that the main channel 7b is connected to the second diversion channel 7d for continuous and stable output.

[0069] For low-capacity operations, such as pilot-scale experiments, where flow rates and output are low, both the return pipe 5 and the output pipe 6 have a diameter of 40mm. This ensures that the flow velocity in the return pipe 5 is above 1.5m / s, preventing blockages in the return pipeline. A piston assembly 7e is reciprocated at a specific pulse frequency, causing the second diversion channel 7d to switch between fully open and fully closed states in a pulsed manner. During continuous production for a period, the cumulative difference between the first flow meter 8 and the second flow meter 9 is used as the output flow rate. The first diversion channel 7b is always open, and the material velocity in the return pipe 5 is high, preventing blockages in the return pipeline. The pulsed opening of the second diversion channel 7d ensures output while preventing blockages in the output pipeline and valves.

[0070] The technical solutions of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention, but the present invention is not limited to the scope of the examples described.

[0071] Application Example 1

[0072] use Figures 3-6 The continuous crystallization system shown is used for pilot-scale continuous crystallization of 4-chloro-3,5-dimethylphenol (PCMX) mother liquor, specifically following these steps:

[0073] (1) The PCMX mother liquor is fed into the heat exchanger 13 through the mother liquor delivery pipe 17 and heated to 80°C, then driven at 5m 3 A flow rate of / h enters crystallizer 1;

[0074] (2) Control the vacuum degree of crystallizer 1 to -0.08MPa so that the mother liquor reaches the boiling state after entering crystallizer 1, and the solvent evaporation rate is maintained at 2m. 3 / h, solvent evaporates in large quantities. When the liquid level in crystallizer 1 reaches the material circulation outlet and circulation can be achieved, reduce the feed rate of the mother liquor to 3m. 3 / h;

[0075] (3) When the solid content in the settling zone at the bottom of crystallizer 1 reaches 30%, open the second shut-off valve 12 on the discharge pipe 3 and the first shut-off valve 11 on the return pipe 5, so that the flow rate of the second flow meter 9 (i.e., the output flow rate of the transfer pump 4) is 8m³. 3 / h, the flow rate of the first flow meter 8 (i.e., the flow rate in the return pipe 5) is 7m³ / h. 3 / h; where the diameter of the discharge pipe 3 is DN50, the diameter of the return pipe 5 is DN40, and the diameter of the extraction pipe 6 is DN40. The control piston assembly 7e reciprocates in the valve body 7a at a certain frequency, causing the second diversion channel 7d to open in a pulsed manner at a frequency of 9s for fully open operation and 51s for fully closed operation, so that the flow rate of the second diversion channel 7d (i.e., the actual crystal slurry extraction flow rate) is 1m³. 3 / h, while the frequency converter synchronously controls the flow rate of delivery pump 4 to 8m³ / h. 3 The continuous crystallization system operates smoothly for 24 hours, with no blockages in pipelines or valves.

[0076] Comparative Example 1

[0077] use Figure 1 The continuous crystallization system was used to continuously crystallize 4-chloro-3,5-dimethylphenol (PCMX) mother liquor. The specific steps are as follows:

[0078] (1) The PCMX mother liquor is fed into the heat exchanger through the mother liquor delivery pipe and heated to 80°C, then driven at 5m... 3 The crystallizer is fed at a rate of / h;

[0079] (2) Control the vacuum degree of the crystallizer to -0.08MPa so that the mother liquor reaches a boiling state after entering the crystallizer, and the solvent evaporation rate is maintained at 2m. 3 / h, solvent evaporates in large quantities. When the liquid level in the crystallizer reaches the material circulation outlet and circulation can be achieved, reduce the feed rate of the mother liquor to 3m. 3 / h;

[0080] (3) When the solid content in the settling zone at the bottom of the crystallizer reaches 30%, turn on the conveying pump 4' on the discharge pipe 3', and turn on the flow regulating valve 6' on the return pipe 5' and the flow regulating valve 6' on the extraction pipe section 3a', so that the flow rate of the discharge pipe 3' is 8m³ / s. 3 / h, the flow rate of the return pipe 5′ is 7m³ / h. 3 / h; where the discharge pipe 3′ ’ The diameter of the main pipe is DN50, the diameter of the return pipe 5' is DN40, and the diameter of the extraction pipe 6' is DN40. At this time, the actual crystal slurry extraction rate is 1m³. 3 / h, the flow velocity in the 3a′ section of the extraction pipe is 0.22m / s (too low a flow velocity can easily cause blockage). As a result, after running the system for 1 hour, production needs to be stopped to unclog the pipes and valves.

[0081] Comparative Example 2

[0082] use Figure 1The continuous crystallization system was used to continuously crystallize 4-chloro-3,5-dimethylphenol (PCMX) mother liquor. The specific steps are as follows:

[0083] (1) The PCMX mother liquor is fed into the heat exchanger through the mother liquor delivery pipe and heated to 80°C, then driven at 5m... 3 The crystallizer is fed at a rate of / h;

[0084] (2) Control the vacuum degree of the crystallizer to -0.08MPa so that the mother liquor reaches a boiling state after entering the crystallizer, and the solvent evaporation rate is maintained at 2m. 3 / h, solvent evaporates in large quantities. When the liquid level in the crystallizer reaches the material circulation outlet and circulation can be achieved, reduce the feed rate of the mother liquor to 3m. 3 / h;

[0085] (3) When the solid content in the settling zone at the bottom of the crystallizer reaches 30%, turn on the conveying pump 4' on the discharge pipe 3', and turn on the flow regulating valve 6' on the return pipe 5' and the flow regulating valve 6' on the extraction pipe section 3a', so that the flow rate of the discharge pipe 3' is 8m³ / s. 3 / h, the flow rate of the return pipe 5′ is 7m³ / h. 3 / h; where the discharge pipe 3′ ’ The diameter of the main pipe is DN50, the diameter of the return pipe 5' is DN40, and the diameter of the extraction pipe 6' is DN15. At this point, the actual slurry extraction rate is 1m³. 3 / h, the flow velocity in the 3a′ section of the extraction pipe is 1.5m / s (the pipe diameter is too small and it is easy to get clogged). As a result, after the system runs for 1 hour, production needs to be stopped to unclog the pipes and valves.

[0086] For low-flow extraction, using Comparative Examples 1 and 2, if a small-diameter extraction pipe is used, although the flow rate can be guaranteed, the extraction pipe is too thin and the slurry is prone to clogging the pipeline; if a large-diameter extraction pipe is used, the flow rate is very low, which can also easily lead to pipeline blockage. However, the regulating valve of this invention can effectively avoid the above situations and ensure continuous extraction.

[0087] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0088] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as exactly that endpoint point. The endpoints of the ranges and any values are understood to be approximate values. For ranges having an upper and lower limit, the range can be understood to include each integer within the defined range. The upper and lower limits of the range can independently be included in the range, or independently excluded from the range. The range can also be understood to include single values within the range, which can be the upper or lower limit of the range. For ranges having an upper and lower limit, the range can be understood to include each integer within the defined range. The upper and lower limits of the range can independently be included in the range, or independently excluded from the range. The range can also be understood to include single values within the range, which can be the upper or lower limit of the range.

Claims

1. A continuous crystallization system comprising a crystallizer and a seed tank, said crystallizer having a discharge port, said discharge port being connected to a discharge pipe, said discharge pipe being connected to said crystallizer by a reflux pipe, said discharge pipe further being connected to said seed tank by a production pipe, characterized in that: The adjusting valve is arranged above the crystal growing tank, the extending direction of the production pipe is consistent with the extending direction of the second branch channel, and the second branch channel extends along the vertical direction or extends along the vertical direction in an inclined manner. The continuous crystallization system further comprises a first flow meter arranged on the backflow pipe, a second flow meter arranged on the discharge pipe, a conveying pump arranged on the discharge pipe, and a frequency converter connected with the conveying pump; and / or, The continuous crystallization system further comprises a heat exchanger, the crystallizer further has a material circulation outlet and a material circulation inlet, a refrigerant inlet of the heat exchanger is connected with the material circulation outlet through a first circulation pipe, a refrigerant outlet of the heat exchanger is connected with the material circulation inlet through a second circulation pipe, the continuous crystallization system further comprises a mother liquor conveying pipe connected with the first circulation pipe and a circulation pump arranged on the first circulation pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, 2. The continuous crystallization system of claim 1, wherein: The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, 3. The continuous crystallization system of claim 1, wherein: The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, 4. A regulating valve for use in the continuous crystallization system of any one of claims 1 to 3, comprising a valve body having a main passage, a first shunt passage and a second shunt passage in communication with each other, characterized in that: The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe; and / or, The continuous crystallization system further comprises a first cut-off valve arranged on the backflow pipe and a second cut-off valve arranged on the discharge pipe When the piston assembly moves to cover the second port, the second shunt passage is in an intermediate working state, and the main passage is in communication with the second shunt passage; when the piston assembly moves to avoid the second port, the second shunt passage is in a fully open working state, and the main passage is in communication with the second shunt passage. The regulating valve is used for conveying solid-liquid mixed materials.

5. The regulating valve according to claim 4, characterized in that: The valve body further has a movement passage for the reciprocating movement of the piston assembly and in communication with the main passage, the first port is located on the side wall of the main passage, and the second port is located on the side wall of the movement passage.

6. The regulating valve according to claim 5, characterized in that: The length extension direction of the movement passage is consistent with the length extension direction of the main passage, and the side surface of the piston assembly facing the main passage is an arc surface.

7. The regulating valve according to claim 6, characterized in that: The radius of the arc surface is greater than or equal to the inner diameter of the main passage.

8. The regulating valve according to claim 5, characterized in that: The valve body comprises a straight pipe portion with openings at both ends, and first and second branch pipe portions connected to opposite sides of the straight pipe portion, respectively, the inside of the straight pipe portion sequentially forms the main passage and the movement passage, respectively, the inside of the first branch pipe portion forms the first shunt passage, and the inside of the second branch pipe portion forms the second shunt passage.

9. The regulating valve according to claim 8, characterized in that: The valve body further comprises a sealing cover arranged at one end of the straight pipe portion close to the movement passage, and one end of the piston assembly extends out of the valve body through the sealing cover; or, The piston assembly comprises a piston body arranged in the valve body, a connecting rod connected to one end of the piston body, and a piston plate connected to the other end of the connecting rod, the valve body further comprises a sealing cover arranged at one end of the straight pipe portion close to the movement passage and a fixing plate arranged between the piston body and the sealing cover, the connecting rod is arranged through the fixing plate, and the piston plate is located between the fixing plate and the sealing cover, a cavity is jointly formed between the fixing plate, the inner wall of the straight pipe portion, and the sealing cover, the piston plate divides the cavity into first and second chambers independent of each other, the first and second chambers have first and second interfaces, respectively, and the first and second interfaces are used for connecting to compressed air pipelines or hydraulic oil pipelines, respectively.

10. The regulating valve according to any one of claims 4 to 9, characterized in that: The inner diameter of the second shunt passage is less than or equal to the inner diameter of the first shunt passage, and the inner diameter of the first shunt passage is less than or equal to the inner diameter of the main passage; and / or, the inner diameter of the second shunt passage is greater than or equal to 40 mm.

11. The regulating valve according to any one of claims 4 to 9, characterized in that: The regulating valve further comprises a driving mechanism for driving the piston assembly to reciprocate.

12. The regulating valve according to claim 11, characterized in that: The driving mechanism is an electric driving mechanism, a pneumatic driving mechanism, or a hydraulic driving mechanism.

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