A reboiler for the rectification of centrifuge mother liquor containing material

Abstract

The utility model provides a kind of for the reboiling device of centrifugal mother liquor rectification of containing material, including rectifying column, several reboilers, circulating pump and external heater;The top of each reboiler is equipped with gas phase export, and gas phase export is linked with rectifying column, and the top of each reboiler is equipped with mother liquor import, and mother liquor import is linked with the bottom discharge port of rectifying column;Circulating pump is used to pump out liquid material in reboiler;The import of external heater is linked with the export of circulating pump, and the export of external heater is linked with reboiler.Circulating flow heating is driven by circulating pump between reboiler and external heater, and solid material is rapidly passed through external heater using the flow rate of material liquid, avoid solid material to settle and wall in external heater.

Description

Technical Field

[0001] This utility model relates to the field of chemical distillation equipment technology, specifically to a reboiling device for distilling centrifuged mother liquor containing feed. Background Technology

[0002] In chemical production, distillation is often used to recover solvents from centrifuged mother liquor containing solids. However, centrifuged mother liquor often contains small amounts of solids, mainly product material, slightly soluble substances, and solid impurities. During distillation, as the solvent is continuously evaporated, the solid components gradually precipitate. These precipitated slightly soluble solids tend to deposit in the reboiler after entering the distillation column, leading to blockage or even carbon buildup, severely impacting normal production.

[0003] To address the aforementioned issues, existing technologies employ a combination of a conventional distillation kettle and a rectification column to recover the centrifuged mother liquor containing the feed material through distillation. Specifically, the mother liquor is first pre-distilled in a distillation kettle to remove most of the solvent before being further purified in a rectification column.

[0004] However, this method is not ideal. There is still a problem that solid materials are carried into the distillation column along with the distillation gas in the distillation kettle. These solid materials are refluxed to the bottom of the column with the high-boiling-point components and then enter the reboiler, which leads to precipitation, wall formation and even carbonization in the reboiler. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of solid deposition in the reboiler during the distillation of centrifugal mother liquor containing materials in the prior art, and to provide a reboiler device for the distillation of centrifugal mother liquor containing materials that can effectively prevent the deposition of solid materials in the heat exchange equipment.

[0006] To achieve the above objectives, this utility model provides a reboiling device for the rectification of centrifugal mother liquor containing material, comprising a distillation column, several reboiling kettles, a circulating pump, and an external heater; each reboiling kettle has a gas phase outlet at the top, which is connected to the distillation column, and a mother liquor inlet at the top, which is connected to the bottom outlet of the distillation column; the circulating pump is used to pump out the liquid material in the reboiling kettle; the inlet of the external heater is connected to the outlet of the circulating pump, and the outlet of the external heater is connected to the reboiling kettle.

[0007] In this invention, a circulating pump drives the liquid to circulate and heat between the reboiler and the external heater. The flow rate of the liquid itself allows the solid material to pass through the external heater quickly, preventing the solid material from settling and forming on the wall inside the external heater.

[0008] Furthermore, the bottom outlet of the distillation column is higher than the inlet height of the mother liquor in the reboiler. By increasing the installation height of the distillation column, the elevation difference allows the mother liquor containing the feed to flow completely into the reboiler by gravity, preventing solid materials from settling and accumulating at the bottom of the column.

[0009] Furthermore, the reboiling unit is equipped with multiple reboiling kettles, which are connected in series or in parallel. The reboiling kettles can be flexibly switched between series or parallel operation modes according to production needs.

[0010] Furthermore, there are two reboilers, namely the first reboiler and the second reboiler.

[0011] Furthermore, the reboiler includes a cylindrical body and a jacket installed on the outer wall of the cylindrical body. The reboiler, in conjunction with the jacket's steam / circulating water switching mechanism, achieves the dual functions of heating distillation and cooling crystallization, enabling the recovery of solid products from the distillation residue.

[0012] Furthermore, the reboiler also includes an agitator, which is located inside the vessel. The agitator continuously stirs the material within the reboiler, keeping the solid material in suspension and preventing it from settling at the bottom.

[0013] Furthermore, the external heater is a shell-and-tube heat exchanger, comprising a shell and tubes disposed inside the shell.

[0014] Furthermore, the reboiling unit also includes a centrifuge connected to the discharge port at the bottom of the reboiler. This centrifuge is used to separate the distillation residue after cooling and crystallization during shutdown, recovering the solid product and improving product yield.

[0015] Furthermore, the reboiler is also equipped with a nitrogen inlet for introducing nitrogen into the reboiler for protection.

[0016] The technical advantages of this application are as follows:

[0017] 1. This utility model uses a circulating pump to make the circulating liquid pass through the external heater at a certain flow rate. The solid material stays briefly when passing through the external heater and will not settle and clump together in the heater. Instead, it returns to the reboiler with the circulating liquid, which effectively solves the problem of blockage of the external heater.

[0018] 2. In this invention, when the distillation system is intermittently shut down, circulating water is introduced through the jacket of the reboiler for cooling and crystallization. In conjunction with a centrifuge, the crystallized material in the distillation residue is separated by centrifugation, and the solid product material is recovered. This effectively improves the product yield and reduces product loss.

[0019] 3. The bottom outlet of the distillation column of this utility model is higher than the mother liquor inlet height of the reboiler, so that the mother liquor with some entrained material in the distillation column can flow into the reboiler by gravity, which effectively reduces the risk of sedimentation and blockage of high-boiling solids at the bottom of the distillation column. Attached Figure Description

[0020] Figure 1 This is a schematic flow diagram of the reboiling device provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the reboiler provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the external heater provided in an embodiment of this utility model.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Distillation column;

[0025] 2. Reboiler; 21. First reboiler; 22. Second reboiler;

[0026] 201. Shell; 202. Jacket; 203. First interface for jacketed medium; 204. Reboiler head; 205. Thermometer port; 206. Mother liquor inlet; 207. Liquid inlet; 208. Agitator; 209. Level gauge port; 2010. Gas phase outlet; 2011. Nitrogen inlet; 2012. Second interface for jacketed medium; 2013. Discharge port;

[0027] 3. Circulating pump;

[0028] 4. External heater; 401. Circulating liquid inlet; 402. Shell; 403. Tubes; 404. Steam inlet; 405. Circulating liquid outlet; 406. Steam condensate outlet;

[0029] 5. Centrifuge. Detailed Implementation

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0031] In existing technologies, the deposition of solid materials in the reboiler leads to frequent blockages, and in severe cases, carbonization occurs, requiring frequent shutdowns for maintenance and affecting production efficiency. Furthermore, high-boiling-point solid impurities settle and accumulate at the bottom of the distillation column, increasing the risk of blockage at the bottom of the column and reducing the safety of the unit's operation.

[0032] To solve these problems, refer to Figure 1This application illustrates an embodiment of a reboiling apparatus for distilling mother liquor containing feedstock. The reboiling apparatus includes: a distillation column 1, several reboiling kettles 2, a circulating pump 3, and an external heater 4. Each reboiling kettle 2 has a gas phase outlet 2010 at its top, which is connected to the distillation column 1. Each reboiling kettle 2 also has a mother liquor inlet 206 at its top, which is connected to the bottom outlet of the distillation column 1. The circulating pump 3 is used to pump out the liquid material in the reboiling kettle 2. The inlet of the external heater 4 is connected to the outlet of the circulating pump 3, and the outlet of the external heater 4 is connected to the reboiling kettle 2, forming a circulating heating loop of the reboiling kettle 2 via the circulating pump 3 and the external heater 4.

[0033] In practical implementation, reboiling units are mainly used in the distillation and recovery process of centrifugal mother liquor containing materials in chemical production. The materials refer to the product entrained in the mother liquor, which can be recovered; the mother liquor refers to a mixed liquid containing materials, solvent, generated water, and a small amount of byproducts; the solvent refers to the solvent liquid recovered after distillation that can be reused in production; high-boiling-point solid impurities refer to high-boiling-point solid impurities in the mother liquor, which require further processing after recovery to separate the product and high-boiling-point solid waste impurities.

[0034] Reference Figure 1 Distillation column 1 is the main site for mother liquor distillation, receiving mother liquor vapor from reboiler 2. In a preferred embodiment, the installation height of distillation column 1 is raised so that the height of its bottom outlet is higher than the height of the mother liquor inlet 206 of reboiler 2. This allows the mother liquor containing some entrained material in distillation column 1 to flow completely into reboiler 2, greatly reducing the risk of sedimentation of high-boiling-point solids such as precipitates in distillation column 1.

[0035] The reboiler 2 mainly contains mother liquor, gaseous solvent, and high-boiling-point impurities. After the mother liquor is heated by steam in the jacket, some of the solvent vapor in the mother liquor enters the distillation column 1 through the gas phase outlet 2010. The lower liquid is pumped into the external heater 4 through the circulation pump 3 from the discharge port 2013 for further heating, and then returns to the reboiler 2 through the liquid inlet 207. The mother liquor distillation is an intermittent operation. When the unit needs to be shut down, circulating water is introduced into the jacket 202 of the reboiler 2 to cool and crystallize the distillation residue, which then enters the centrifuge 5 through the discharge port 2013. Preferably, the reboiler 2 also includes a stirrer 208, which is located inside the cylinder 201. The stirrer 208 continuously stirs the material in the reboiler 2, keeping the solid material in suspension and preventing sedimentation at the bottom.

[0036] The circulating pump 3 is used to pump the liquid material in the reboiler 2 into the external heater 4 for further heating. The circulating pump 3 ensures the circulating liquid flows rapidly through the tubes of the external heater 4 at a certain velocity, preventing solids in the circulating liquid from settling and forming on the walls of the tubes 403. The solids then return to the reboiler 2 with the circulating liquid. The purpose of the external heater 4 is to ensure the heat exchange requirements of the distillation process and to further heat the mother liquor in the reboiler 2. The circulating pump 3 drives the liquid to circulate and heat between the reboiler 2 and the external heater 4. The flow rate of the liquid itself allows solids to pass quickly through the external heater 4, preventing them from settling and forming on the walls of the external heater 4.

[0037] In some preferred embodiments of this application, there are multiple reboiler kettles 2, which are connected in series or in parallel. In one embodiment, two reboiler kettles 2 are used. In specific implementation, the first reboiler kettle 21 and the second reboiler kettle 22 are connected in series and parallel. When operating in series, the mother liquor from the distillation column 1 first enters the first reboiler kettle 21 for primary heating and distillation, and the incompletely evaporated material overflows to the second reboiler kettle 22 for secondary heating and distillation, achieving a multi-stage distillation effect; or, during the shutdown crystallization stage, the crystallized material can be first cooled in the first reboiler kettle 21 and then transferred to the second reboiler kettle 22 for secondary cooling to obtain a better crystallization effect.

[0038] In parallel operation, the first reboiler 21 and the second reboiler 22 simultaneously receive mother liquor from the distillation column 1 and perform the same distillation or crystallization operations in parallel, thereby increasing processing capacity. In actual production, the series or parallel operation mode can be flexibly selected according to factors such as material characteristics and processing volume.

[0039] The series-parallel connection of the two reboilers 2 provides a flexible operating mode, which can not only meet the requirements of mother liquor classification under different process conditions, but also improve the system's processing capacity and operational flexibility.

[0040] Reference Figure 2 In some preferred embodiments of this application, the reboiler 2 includes a cylindrical body 201 and a jacket 202 disposed on the outer wall of the cylindrical body 201. The jacket 202 is provided with a medium inlet and a medium outlet, which can be switched to allow steam or circulating water to be introduced into the reboiler 2, so that steam is introduced into the reboiler 2 for heating and distillation during rectification, and circulating water is introduced into the reboiler 2 for cooling and crystallization during crystallization.

[0041] Specifically, the jacket 202 of the reboiler 2 is provided with a first jacket medium interface 203 and a second jacket medium interface 2012.

[0042] During the distillation operation, the steam inlet valve at the first interface 203 of the jacket medium and the steam condensate outlet valve at the second interface 2012 of the jacket medium are opened to introduce steam into the jacket 202, thereby raising the temperature of the jacket 202 and distilling the mother liquor in the reboiler 2. The distilled gaseous solvent enters the distillation column 1 through the gas phase outlet 2010 for distillation purification.

[0043] When the intermittently operating mother liquor distillation system is about to shut down, close the steam inlet valve at the first interface 203 of the jacket medium and the steam condensate outlet valve at the second interface 2012 of the jacket medium, and open the corresponding circulating water inlet and outlet valves to redirect circulating water into the jacket 202. This cools the remaining liquid in the reboiler 2, allowing the distillation residue to cool and crystallize. The dual-purpose jacket 202 meets both the heating requirements during distillation and the cooling and crystallization requirements during shutdown.

[0044] The jacket 202 of the reboiler 2 can flexibly switch between steam heating and circulating water cooling, realizing the dual function of the reboiler 2, simplifying the equipment structure, reducing equipment investment costs, and creating conditions for the recovery of products from distillation residue.

[0045] Reference Figure 3 In some preferred embodiments of this application, the external heater 4 is a shell-and-tube heat exchanger, including a shell 402 and tubes 403 disposed inside the shell 402. The tube side of the shell-and-tube heat exchanger is a mother liquor passage, and the shell side is a steam passage.

[0046] Specifically, the external heater 4 includes a circulating liquid inlet 401, a shell 402, tubes 403, a steam inlet 404, a circulating liquid outlet 405, and a steam condensate outlet 406. The tube side serves as the mother liquor channel, where the circulating liquid from the reboiler 2 enters the tubes 403 through the circulating liquid inlet 401; the shell side serves as the steam channel, where steam enters the space between the shell 402 and the tubes 403 through the steam inlet 404. The steam heats the circulating liquid inside the tubes through the tube walls of the tubes 403, and the heated circulating liquid returns to the reboiler 2 through the circulating liquid outlet 405. The steam condensate is discharged through the steam condensate outlet 406. The shell-and-tube heat exchanger has the advantages of compact structure, large heat exchange area, and high heat exchange efficiency, and can meet the heat exchange requirements of the distillation process.

[0047] In some preferred embodiments of this application, the reboiling device further includes a centrifuge 5, and the bottom of the reboiling vessel 2 is provided with a discharge port 2013, which is connected to the centrifuge 5.

[0048] Specifically, centrifuge 5 is located below reboiler 2 and connected to discharge port 2013 at the bottom of reboiler 2 via a pipeline. When the mother liquor distillation system operates intermittently and enters the shutdown phase, the remaining liquid in reboiler 2 is cooled by circulating water through jacket 202 and crystallized. The crystallized material is then fed into centrifuge 5 through discharge port 2013 for centrifugal separation. After centrifugation, the solid material is collected and sent to a dedicated waste recovery device for further separation of the product and high-boiling-point solid waste impurities. The final product is recovered, and the solid waste impurities are collected and centrally processed. The mother liquor after centrifugation is sent to a mother liquor storage tank, where it can be re-entered into the distillation system for further processing.

[0049] In some preferred embodiments of this application, when the distillation system is shut down, circulating water is introduced into the jacket 202 of the reboiler 2 to cool and crystallize the remaining liquid. The crystallized material is then discharged into the centrifuge 5 through the discharge port 2013 for centrifugal separation. The solid material obtained from centrifugal separation is collected and sent to a recovery device for further processing. Specifically, the mother liquor distillation is carried out in an intermittent operation mode. When the unit needs to be shut down, the steam valves at the jacket medium first interface 203 and the steam condensate outlet 406 of the reboiler 2 are first closed. Then, the corresponding circulating water inlet and outlet valves are opened to introduce circulating cooling water into the jacket 202. The circulating water cools the remaining liquid in the reboiler 2 through the jacket 202. As the temperature decreases, the material in the liquid gradually crystallizes and precipitates. When the liquid temperature drops to the crystallization temperature, the valve at the discharge port 2013 at the bottom of the reboiler 2 is opened to discharge the crystallized material into the centrifuge 5. By taking advantage of the intermittent shutdowns of the distillation system for cooling crystallization and solid waste collection, production and maintenance are seamlessly integrated. This allows for the effective recovery of products and the removal of solid residues from the system without affecting normal production.

[0050] Reference Figure 2 In some preferred embodiments of this application, the reboiler 2 is equipped with a thermometer port 205 and a level gauge port 209. The thermometer port 205 is used to install a temperature sensor or thermometer to monitor the temperature of the feed liquid in the reboiler 2 in real time. Operators can adjust the flow rate of steam or circulating water in the jacket 202 based on the temperature data to control the distillation or crystallization rate. The level gauge port 209 is used to install a level gauge to monitor the liquid level in the reboiler 2 in real time, ensuring that the liquid level operates within a safe range and preventing problems such as liquid carryover in the vapor phase due to excessively high liquid levels or uneven heating due to excessively low liquid levels. Temperature and level monitoring and control are crucial parameters for ensuring the safe and stable operation of the distillation system.

[0051] Reference Figure 2In some preferred embodiments of this application, the reboiler 2 is further provided with a nitrogen inlet 2011 for introducing nitrogen gas into the reboiler 2 for protection. Before or during distillation operation, nitrogen gas can be introduced into the reboiler 2 through the nitrogen inlet 2011 to provide nitrogen-sealed protection inside the vessel, reduce oxygen content, prevent flammable and explosive solvent vapors from mixing with air to form an explosive gas, and ensure production safety. Simultaneously, nitrogen protection also helps prevent the material from oxidizing and deteriorating at high temperatures. During shutdown maintenance, the introduction of nitrogen gas can also purge and replace the contents of the vessel, providing a safe working environment for maintenance personnel.

[0052] Combination Figures 1 to 3 The working process of a preferred embodiment of this utility model will be described in detail below:

[0053] Distillation Operation Stage: The mother liquor from distillation column 1 flows by gravity into reboiler 2. Valves at the second jacket medium interface 2012 and the first jacket medium interface 203 of reboiler 2 are opened to heat the jacket 202, distilling the mother liquor. The distilled gaseous solvent enters distillation column 1 through gas phase outlet 2010 for purification. The liquid mother liquor in reboiler 2 is discharged from the bottom discharge port 2013 and pumped into the circulating liquid inlet 401 of external heater 4 by circulating pump 3. Valves at steam condensate outlet 406 and steam inlet 404 are opened to introduce steam into the shell side of external heater 4, reheating the circulating liquid passing through the tube side of external heater 4. The heated circulating liquid returns to reboiler 2 through circulating liquid outlet 405 and inlet 207, thus repeating the cycle. During operation, the temperature of reboiler 2 is controlled within the range of 70-90℃, and the liquid level is maintained between 1 / 3 and 1 / 2.

[0054] During the shutdown crystallization stage: When the intermittently operating mother liquor distillation system is about to shut down, close the steam valves at the first interface 203 and the second interface 2012 of the jacket medium of the reboiler 2, and open the corresponding circulating water inlet and outlet valves to redirect circulating water into the jacket 202. This cools the remaining liquid in the reboiler 2 to below 10°C, allowing it to crystallize. Open the valve at the discharge port 2013 at the bottom of the reboiler 2 to discharge the crystallized material into the centrifuge 5 for centrifugal separation. The solid material obtained from centrifugal separation is collected and sent to a dedicated waste recovery device for further separation of the product and high-boiling-point solid waste impurities. The final product is recovered, and the solid waste impurities are collected and centrally processed. The centrifugal mother liquor is sent to the mother liquor storage tank.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A reboiler apparatus for rectification of a feed containing centrifuge mother liquor, characterized in that, include: Distillation column (1); Several reboiler (2), each reboiler (2) is provided with a gas phase outlet (2010) at the top, the gas phase outlet (2010) is connected to the distillation column (1), and each reboiler (2) is provided with a mother liquor inlet (206) at the top, the mother liquor inlet (206) is connected to the bottom outlet of the distillation column (1); Circulating pump (3); An external heater (4) is provided, the inlet of which is connected to the outlet of the circulating pump (3), and the outlet of which is connected to the reboiler (2).

2. The reboiling apparatus according to claim 1, characterized in that, The bottom outlet of the distillation column (1) is higher than the mother liquor inlet (206) of the reboiler (2).

3. The reboiling apparatus according to claim 1, characterized in that, The reboiling device is equipped with multiple reboiling kettles (2), which are connected in series or in parallel.

4. The reboiling apparatus according to claim 1 or 3, characterized in that, The reboiler (2) consists of two units, namely the first reboiler (21) and the second reboiler (22).

5. The reboiling apparatus according to claim 1, characterized in that, The reboiler (2) includes a cylinder (201) and a jacket (202) disposed on the outer wall of the cylinder (201).

6. The reboiling apparatus according to claim 5, characterized in that, The reboiler (2) also includes a stirrer (208) disposed inside the cylinder (201).

7. The reboiling apparatus according to claim 1, characterized in that, The external heater (4) is a shell-and-tube heat exchanger, including a shell (402) and a shell (403) disposed inside the shell (402).

8. The reboiling apparatus according to claim 1, characterized in that, It also includes a centrifuge (5), which is connected to the discharge port (2013) at the bottom of the reboiler.

9. The reboiling apparatus according to claim 1, characterized in that, The reboiler (2) is also equipped with a nitrogen inlet (2011).

Images