A continuous preparation system and process for sodium methoxide methanol solution

Abstract

The present application provides a kind of sodium methoxide methanol solution continuous preparation system, including alkali preparation tank, multiple alkali buffer tank, first cooler and second cooler.The present application sets up multiple alkali buffer tank switching to carry out solid alkali continuous feeding, can reduce the loss of raw material methanol;Methanol vapor is cooled by first cooler, recycling methanol and discharging moisture, promoting the reaction to proceed and reducing the content of free alkali in sodium methoxide methanol solution, reducing the difficulty of subsequent purification treatment;Reaction liquid is circulated and cooled by second cooler, to prevent safety accidents caused by high temperature, while the returned reaction liquid forms automatic circulation stirring vortex, to promote uniform mixing of raw materials to improve reaction and production efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical synthesis, in particular to a continuous preparation system and process of sodium methoxide methanol solution. BACKGROUND

[0002] Sodium methoxide (chemical formula CH3ONa) is often used as an intermediate for the synthesis of medicines and pesticides, as a condensing agent, a chemical reagent, a catalyst for the treatment of edible oils and fats, etc. in organic synthesis. The production method of sodium methoxide mainly includes a metal sodium method and an alkali method. Since the metal sodium is expensive and the production process of the metal sodium method is extremely unsafe, the alkali method is commonly used for preparing sodium methoxide in the current domestic industrial production.

[0003] The alkali method refers to preparing sodium methoxide by using sodium hydroxide and anhydrous methanol as raw materials through processes such as alkali preparation, intermediate tank standing, gas stripping and methanol rectification. Among them, the sodium methoxide methanol solution is obtained through the alkali preparation process, and the specific process is as follows: the solid alkali is gradually added into the anhydrous methanol to dissolve to generate sodium methoxide and water, and the reaction formula is as follows:

[0004] NaOH + CH3OH → CH3ONa + H2O

[0005] The reaction is a strong reversible reaction, and the reverse reaction easily leads to a large amount of free alkali in the sodium methoxide methanol solution obtained after the reaction, which can decompose the fat in the reactants or products when the sodium methoxide methanol solution participates in the pharmaceutical synthesis reaction, thereby seriously affecting the activity of sodium methoxide. Therefore, the generated water needs to be continuously removed in the alkali preparation process to ensure that the reaction continuously proceeds in the forward direction.

[0006] It should be noted that a large amount of reaction heat is released during the dissolution of sodium hydroxide in anhydrous methanol, and if the heat is not discharged in time, a safety accident can easily occur. In addition, when the temperature reaches the boiling point of methanol, a large amount of methanol used to dissolve the solid alkali is vaporized. At present, the alkali preparation process in the process flow of the alkali method for generating sodium methoxide is mostly intermittent operation, and the degree of automation is not high. During the uncapped feeding process, methanol leakage can occur, which not only causes raw material loss, but also increases environmental pollution and safety production risk. SUMMARY

[0007] In view of the deficiencies in the prior art, the present application discloses a continuous preparation system and process of sodium methoxide methanol solution. The raw materials sodium hydroxide and methanol are continuously added in the process, and the reaction heat and the generated water are discharged in time through two-stage cooling processes during the alkali preparation process, so as to promote the continuous, efficient and safe preparation of the sodium methoxide methanol solution.

[0008] In order to achieve the above technical purposes, on the one hand, the present application provides a continuous preparation system of sodium methoxide methanol solution, which comprises an alkali preparation tank, and a liquid inlet pipe is connected to the top of the alkali preparation tank, which is used to input methanol into the alkali preparation tank.

[0009] a plurality of alkali buffer tanks for temporarily storing and feeding solid alkali into the alkali preparation tank; the feed inlet of the alkali buffer tank is connected with the hinge conveyor through a pipeline, and the discharge outlet is connected with the top of the alkali preparation tank through a pipeline;

[0010] the discharge outlet at the top of the alkali preparation tank is connected with the inlet of the first cooler through a pipeline, and the outlet of the first cooler is connected with the top of the alkali preparation tank through a liquid seal device;

[0011] the lower discharge outlet of the alkali preparation tank is connected with a circulating pump, the first branch of the circulating pump is divided into a plurality of reflux branches through a second cooler, and the plurality of reflux branches are respectively connected with the lower part of the alkali preparation tank; the second branch of the circulating pump is connected with a downstream process.

[0012] In the present application, methanol is used as the abbreviation of anhydrous methanol, and the sodium methoxide methanol solution is a solution formed by dissolving sodium methoxide in methanol.

[0013] In the above technical solution, the alkali buffer tanks are switched to discharge / charge, so that the solid alkali raw material is continuously fed into the alkali preparation tank, while avoiding methanol loss and improving operation safety.

[0014] Optionally, the number of alkali buffer tanks is 2-4, the feed inlet of any alkali buffer tank is connected with the discharge outlet of the hinge conveyor through a pipeline to feed solid alkali into the buffer tank, and the discharge outlet is connected with the top of the alkali preparation tank through a pipeline, so that a plurality of solid alkali feed inlets are uniformly distributed along the circumference at the top of the alkali preparation tank, and the uniformly distributed solid alkali feed inlets promote uniform distribution of the raw material in the alkali preparation tank, thereby improving reaction efficiency.

[0015] Optionally, a first shut-off valve is arranged at the top of any alkali buffer tank, a weighing instrument is arranged on the tank body, a second shut-off valve and a rotary discharge valve are arranged on the pipeline connected with the discharge outlet thereof. The first shut-off valve and the second shut-off valve can open / seal the alkali buffer tank, which is conducive to the isolation switching of feeding / discharging between the alkali buffer tanks; the weighing instrument is used to judge the amount of material in the tank body, and further judge the timing of feeding / discharging switching of the alkali buffer tank. Those skilled in the art can set a reasonable number of alkali buffer tanks and a reasonable alkali buffer tank switching mode through non-creative labor to realize continuous feeding of solid alkali during preparation of the sodium methoxide methanol solution, and the technical solutions formed thereby are within the scope of the present application.

[0016] In the above technical solution, the methanol steam caused by the reaction heat of sodium methoxide preparation includes methanol and water generated by the reaction, the methanol steam is fed into the first cooler through a pipeline from the discharge outlet at the top of the alkali preparation tank, and after cooling, liquid-phase methanol and water vapor are obtained, the water vapor is discharged through a pipeline, and the liquid-phase methanol is returned to the alkali preparation tank.

[0017] Optionally, the liquid phase condensed by the first cooler in the present application is returned to the alkali preparation tank after being liquid-sealed by a liquid sealing device. Optionally, the liquid sealing device can be a liquid storage tank or a liquid sealing pipe, and the specific liquid sealing height can be set according to the operating pressure of the alkali preparation tank. In the present application, the liquid storage tank is not provided, and ordinary skilled persons in the art can select a vertical liquid storage tank or a horizontal liquid storage tank to realize liquid sealing through non-creative labor, and the technical solutions formed thereby are within the protection scope of the present application.

[0018] Optionally, the top discharge port of the alkali preparation tank is connected to the first cooler and the liquid storage tank in sequence through pipelines; and the outlet of the liquid storage tank is connected to the top of the alkali preparation tank through a pipeline.

[0019] In the existing sodium methoxide solution preparation process, sodium hydroxide and methanol solution flow from the top of the alkali preparation tank, so that the solution inside the alkali preparation tank is unevenly distributed, resulting in low production efficiency of sodium methoxide. In the prior art, a stirring device is used to promote the mixing of raw materials and improve the dissolution speed of the alkali, but the stirring device needs to be manually turned on and turned off after a certain period of time. The intermittent operation of the stirring device restricts the improvement of production efficiency.

[0020] In the above technical solution, the reaction liquid in the alkali preparation tank is forced to circulate and cool through the second cooler under the action of the circulating pump, which can effectively control the temperature of the reaction system, prevent safety accidents caused by overheating in the alkali preparation tank, and also realize automatic reflux stirring, save equipment investment and energy consumption, and improve production efficiency.

[0021] Optionally, the connection ports of the plurality of reflux branches to the alkali preparation tank are uniformly distributed along the circumference of the alkali preparation tank.

[0022] Optionally, the end of each of the plurality of reflux branches extends into the alkali preparation tank and is inclined downward at a certain angle, so that the external circulating process liquid is input into the alkali preparation tank from different positions on the tank body at a certain height and angle, thereby forming a vortex for automatic stirring inside the alkali preparation tank, and realizing automatic stirring. Therefore, the present application does not need manual stirring, and does not need additional stirring equipment to realize automatic stirring of the reaction liquid in the alkali preparation tank, thereby saving labor and equipment investment and improving production efficiency.

[0023] Optionally, one end of each of the plurality of reflux branches extends into the alkali preparation tank and is inclined downward at a certain angle, so that the external circulating process liquid is input into the alkali preparation tank from different positions on the tank body at a certain height and angle, thereby forming a vortex for automatic stirring inside the alkali preparation tank, and realizing automatic stirring. Therefore, the present application does not need manual stirring, and does not need additional stirring equipment to realize automatic stirring of the reaction liquid in the alkali preparation tank, thereby saving labor and equipment investment and improving production efficiency.

[0024] The basicity of sodium methoxide is stronger than that of sodium hydroxide, so sodium methoxide reacts with water to generate methanol and sodium hydroxide. In the preparation process of sodium methoxide, if the generated water cannot be discharged in time, free alkali will be contained in the sodium methoxide methanol solution, increasing the difficulty of subsequent purification.

[0025] In the above technical solution, a filter or multiple filters in parallel are arranged on the pipeline connected to the lower outlet of the alkali preparation tank; and a differential pressure gauge is arranged on the filter. The filter is used to filter the free alkali in the produced liquid from the lower outlet of the alkali preparation tank; the multiple filters in parallel can be switched; and the differential pressure gauge is used to monitor whether the pressure difference before and after the filter exceeds a set value, thereby providing a basis for switching the filter. The arrangement of the filter can effectively reduce the content of free alkali in the sodium methoxide-methanol solution, ensure continuous production, reduce the difficulty of subsequent operation, and improve the quality of the sodium methoxide-methanol solution.

[0026] It should be noted that the present application can effectively reduce the content of water in the reaction system by discharging the water vapor generated by the reaction through the first cooler.

[0027] In order to achieve the above technical purposes, on the other hand, the present application proposes a continuous preparation process of sodium methoxide-methanol solution, which comprises the following steps:

[0028] The reaction process: the solid alkali input from the alkali buffer tank reacts with the methanol input from the liquid inlet pipe in the alkali preparation tank to generate sodium methoxide, and the sodium methoxide-methanol solution is output from the lower part of the alkali preparation tank and transported to the downstream process;

[0029] The first cooling process: the mixed gas formed by the reaction heat is output from the top of the alkali preparation tank and cooled by the first cooler to obtain liquid phase methanol, and the part of the liquid phase methanol is returned to the alkali preparation tank;

[0030] The second cooling process: the external circulation process liquid is output from the lower part of the alkali preparation tank, and after being cooled by the second cooler, the external circulation process liquid is divided into multiple refluxes and returned to the lower part of the alkali preparation tank.

[0031] Optionally, in the reaction process, the mass ratio of the raw material solid alkali to methanol is 1:7.5-12, the operating temperature is 25-55℃, and the operating pressure is 5-15kPaG, preferably 10kPaG. By adjusting the appropriate mass ratio of solid alkali to methanol, the preparation reaction of sodium methoxide is promoted to proceed in the positive direction. The mass ratio of the feed can promote the preparation reaction of sodium methoxide to proceed in the positive direction.

[0032] Optionally, the temperature of the first cooler and the second cooler is 40-50℃. It should be noted that the temperature of the cooler in the present application refers to the outlet temperature of the cooler.

[0033] Optionally, the volume ratio of the produced sodium methoxide-methanol solution to the external circulation process liquid is 1:5-9.

[0034] Compared with the prior art, the sodium methoxide methanol solution continuous preparation system of the present application sets multiple alkali buffer tanks to switch for continuous feeding of solid alkali, which can reduce the loss of raw material methanol and realize continuous feeding of solid methanol; the methanol vapor generated by the reaction is cooled by the first cooler to recycle the methanol and discharge the water; the reaction liquid is circulated and cooled by the second cooler to prevent safety accidents caused by excessively high temperature, and to form an automatic circulating stirring vortex for the returned external circulation process liquid to promote uniform mixing of raw materials, thereby realizing continuous preparation of sodium methoxide methanol solution. The sodium methoxide methanol solution continuous preparation process based on the above system realizes continuous feeding of raw materials by setting an inlet pipe and multiple alkali buffer tanks, recycles the methanol vapor generated by the reaction heat and discharges the water through a primary cooling process; the reaction liquid is circulated and cooled through a secondary cooling process to prevent safety accidents caused by excessively high temperature, and to form an automatic circulating stirring vortex for the returned external circulation process liquid to promote uniform mixing of raw materials, thereby realizing continuous preparation of sodium methoxide methanol solution. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The illustrations are shown to explain the present application and are not intended to limit the present application unduly.

[0036] Figure 1 The structure diagram of the sodium methoxide methanol solution continuous preparation process of the present application is shown.

[0037] In the above drawings, the following reference signs are included: 10 - alkali preparation tank, 11 - remote liquid level meter, 20 - inlet pipe, 21 - flow meter, 22 - flow regulating valve, 30 - alkali buffer tank, 31 - first shut-off valve, 32 - weighing instrument, 33 - rotary discharge valve, 34 - second shut-off valve, 40 - analyzer, 50 - first cooler, 6 - liquid seal pipe, 70 - circulating pump, 71 - first branch, 72 - second branch, 80 - second cooler, 81 - backflow branch, 90 - filter, 91 - differential pressure meter. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the preferred embodiments of the present application. However, it should be understood that these embodiments are merely used to illustrate the present application in more detail, and should not be construed as limiting the present application in any form, i.e., not intended to limit the protection scope of the present application.

[0039] It should be noted that, except for the definition, the technical terms used in the following embodiments have the same meaning as generally understood by those skilled in the art to which the present application belongs. The relational terms such as "first", "second", "primary", "secondary" and the like in the present embodiment are only used to distinguish one component from another component with the same name, and do not necessarily require or imply any such actual relationship or order between the components. The features limited by "first", "second", "primary", "secondary" and the like can be explicitly or implicitly included one or more features.

[0040] In the description of the present application, unless otherwise explicitly specified and limited, the term "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal connection of two elements. For those skilled in the art, the specific meaning of the above-mentioned term in the present application can be understood according to the specific circumstances.

[0041] Embodiment 1

[0042] A continuous preparation system of sodium methoxide methanol solution, as shown in Figure 1 The system comprises an alkali preparation tank 10, and a liquid inlet pipe 20 connected to the top of the alkali preparation tank 10, which is used to input methanol into the alkali preparation tank 10;

[0043] It also comprises a plurality of alkali buffer tanks 30, which are used to temporarily store and input solid alkali into the alkali preparation tank 10; the feed inlet of the alkali buffer tank 30 is connected to the hinge conveyor through a pipeline, and the discharge outlet is connected to the top of the alkali preparation tank 10 through a pipeline;

[0044] The top discharge outlet of the alkali preparation tank 10 is connected to the inlet of a first cooler 50 through a pipeline, and the outlet of the first cooler 50 is connected to the top of the alkali preparation tank 10 through a liquid seal device;

[0045] The lower part of the alkali preparation tank 10 is connected to a circulating pump 70, and the first branch 71 of the circulating pump 70 is divided into a plurality of return branches 81 through a second cooler 80, and the plurality of return branches 81 are respectively connected to the lower part of the alkali preparation tank 10; the second branch 72 of the circulating pump 70 is connected to a downstream process.

[0046] Optionally, the number of alkali buffer tanks 30 is 2-4, and the continuous feeding of solid alkali is realized by switching the feeding / discharge of the plurality of alkali buffer tanks 30.

[0047] In this embodiment, a continuous preparation system for sodium methoxide methanol solution with three alkali buffer tanks 30 is used as an example. In specific operation, any one of the alkali buffer tanks 30 can be set to discharge state, that is, to input solid alkali into the alkali preparation tank 10; the second alkali buffer tank 30 is in a state of full load of solid alkali. When the first alkali buffer tank 30 reaches the lower limit (adjustable) of the solid alkali load, the second alkali buffer tank 30 will be switched to discharge state. It should be noted that the "full load" state of the alkali buffer tank 30 means that the mass of solid alkali loaded in it reaches the upper limit (adjustable) of the weighing instrument 32 above it. The set value of the full load solid alkali mass can be set according to the specific working conditions; the third alkali buffer tank 30 is in a feeding state, and solid alkali is input into the tank by the hinged conveyor. After the third alkali buffer tank 30 reaches the full load state, the first shut-off valve 31 will be closed and it will enter the standby discharge state.

[0048] Optionally, the connection ports of the return branch 81 and the alkali mixing tank 10 are evenly distributed along the circumference of the alkali mixing tank 10.

[0049] Optionally, the end of the reflux branch 81 extends into the alkali mixing tank 10 and slopes downward at a certain angle.

[0050] Optionally, the liquid sealing device is a liquid sealing pipe or a liquid storage tank. For example... Figure 1 In the continuous preparation system of sodium methoxide methanol solution shown, the top outlet of the alkali preparation tank 10 is connected to the inlet of the first cooler 50 via a pipeline, and the outlet of the first cooler 50 is connected to the top of the alkali preparation tank 10 via a liquid seal pipe 6.

[0051] Optionally, the top outlet of the alkali mixing tank 10 is connected to the first cooler 50 and the storage tank in sequence via pipelines; the outlet of the storage tank is connected to the top of the alkali mixing tank 10 via pipelines.

[0052] It should be noted that the present invention includes a first cooler 50 to discharge water vapor, and a filter 90 or multiple filters 90 connected in parallel on the pipeline connected to the lower outlet of the alkali tank 10 to filter free alkali in the reaction system. This can effectively reduce the content of free alkali in the sodium methoxide methanol solution, thereby reducing the difficulty of subsequent operations and improving the quality of the sodium methoxide methanol solution.

[0053] It should be noted that the methanol feed flow rate is controlled by installing a flow meter 21 on the inlet pipe 20, a remote level gauge 11 on the alkali preparation tank 10, and an analyzer 40 at the lower outlet of the alkali preparation tank 10. Simultaneously, by adjusting the appropriate mass ratio of solid alkali to methanol in the feed, the forward reaction of sodium methoxide preparation is promoted.

[0054] It should be noted that the present application improves the automation degree of the process, saves labor and reduces the industrial operation cost by setting the signal connection of the sodium methoxide methanol solution continuous preparation system, and realizing the automatic interlocking control of the alkali buffer tank 30 feed / drainage automatic switching, methanol feed flow regulation, alkali preparation tank 10 liquid level interlocking regulation, sodium methoxide concentration regulation in the reaction system based on the DCS system.

[0055] It should be noted that the present application can keep the solid alkali and methanol feed mass ratio within the normal operation range by controlling the opening and closing of the regulating valve and the rotating speed of the rotary discharge valve 33 based on the monitoring of the weighing instrument 32 and the flow meter 21 during the operation process of the sodium methoxide methanol solution continuous preparation system. The automatic regulation of the solid alkali and methanol feed flow can also be realized by setting a suitable proportioning range in the DCS system.

[0056] Example 2

[0057] In this embodiment, the signal connection of the sodium methoxide methanol solution continuous preparation system is set to improve the automation degree of the process and reduce the industrial operation cost. It should be pointed out that most chemical enterprises have configured DCS systems in the factory area now, and the process and system of the present application can rely on the original system, and the devices and equipment for interlocking control are added to the original DCS system to realize automatic interlocking control. The present application can realize automatic continuous feeding by setting the feed / drainage switching mode between multiple alkali buffer tanks 30 through the DCS system.

[0058] In this embodiment, the flow meter 21 and the flow regulating valve 22 connected with the signal thereof are arranged on the liquid inlet pipe 20, and the flow meter 21 and the flow regulating valve 22 interlock control the methanol feed flow.

[0059] Optionally, the flow meter 21 is a vortex flow meter.

[0060] It should be noted that the flow meter 21 is provided with multiple alarm levels and multiple flow interlocking, when the methanol flow monitored by the flow meter 21 reaches or is lower than a lower limit value (adjustable), the flow meter 21 will issue a lower limit value alarm, and at the same time interlock to increase the opening degree of the regulating valve; when the methanol flow monitored by the flow meter 21 reaches or is higher than an upper limit value (adjustable), the flow meter 21 will issue an upper limit value alarm, and at the same time interlock to decrease the opening degree of the regulating valve, so as to control the methanol feed flow.

[0061] In this embodiment, the first cut-off valve 31 is arranged at the top of any alkali buffer tank 30, the weighing instrument 32 is arranged on the tank body, the second cut-off valve 34 and the rotary discharge valve 33 are arranged on the pipeline connected with the discharge port thereof, and the first cut-off valve 31, the second cut-off valve 34 and the rotary discharge valve 33 interlock control the feed and discharge of the alkali buffer tank 30 with the weighing instrument 32.

[0062] Optionally, the first cut-off valve 31 used in the present application can be a plug valve, further optionally a manual plug valve, an electric plug valve, an electro-hydraulic plug valve or an electro-pneumatic plug valve, etc.

[0063] It is noted that the weighing instrument 32 is provided with multi-stage alarm and multi-stage weight interlocking. When the monitoring value of the weighing instrument 32 on the alkali buffer tank 30 reaches or is lower than a lower limit value (adjustable), the weighing instrument 32 will issue a lower limit value alarm, and simultaneously interlock the rotary discharge valve 33 to be closed and the first cut-off valve 31 to be opened, so as to input solid alkali into the alkali buffer tank 30; when the monitoring value of the weighing instrument 32 on the alkali buffer tank 30 reaches or is higher than a higher limit value (adjustable), the weighing instrument will issue a higher limit value alarm, and simultaneously interlock the first cut-off valve 31, so that the alkali buffer tank 30 enters a standby discharge state.

[0064] In the present embodiment, a remote liquid level meter 11 is arranged on the alkali preparation tank 10, and the remote liquid level meter 11 is in signal connection with the flow regulating valve 22 on the liquid inlet pipe 20.

[0065] It is noted that the remote liquid level meter 11 is provided with multi-stage alarm and multi-stage liquid level interlocking. When the remote liquid level meter 11 monitors that the liquid level in the alkali preparation tank 10 reaches or is lower than a lower limit value (adjustable), the remote liquid level meter 11 will issue a lower limit value alarm, and simultaneously interlock the opening degree of the regulating valve to be increased; when the remote liquid level meter 11 monitors that the liquid level in the alkali preparation tank 10 reaches or is higher than a higher limit value (adjustable), the remote liquid level meter 11 will issue a higher limit value alarm, and simultaneously interlock the opening degree of the regulating valve to be decreased, so as to control the liquid level height in the alkali preparation tank 10.

[0066] In the present embodiment, an analyzer 40 is arranged on the pipeline connected to the lower discharge port of the alkali preparation tank 10, and the analyzer 40 is in signal connection with the flow regulating valve 22 on the liquid inlet pipe 20.

[0067] It is noted that the analyzer 40 is in signal connection with the regulating valve on the liquid inlet pipe 20, and the type of the analyzer 40 used in the present application is not limited. Both automatic and manual analyzers 40 can be used, and the automatic sampling analyzer 40 is preferred. The analyzer 40 is used to monitor the content of sodium methoxide in the sodium methoxide methanol solution output from the alkali preparation tank 10, which can be displayed in the form of mass concentration, molar mass fraction, molar concentration, molar volume or other forms. The analyzer 40 is set with a normal value (adjustable) and an abnormal value alarm interlocking. When the monitored value is lower than the normal value, an abnormal value alarm is issued and the opening degree of the regulating valve on the liquid inlet pipe 20 is decreased to reduce the feed amount of methanol; when the monitored value is higher than the normal value, an abnormal value alarm is issued and the opening degree of the regulating valve on the liquid inlet pipe 20 is increased to increase the feed amount of methanol; and when the monitored value is far lower than the normal value, the analyzer 40 is interlocked to stop.

[0068] In addition, in the embodiment, the mass ratio of the solid base and the methanol can be set in the DCS system, and the opening and closing of the regulating valve and the rotating speed of the discharge valve 33 can be adjusted through interlocking control, so that the mass ratio of the two raw materials is kept in the normal operating range.

[0069] It should be noted that those skilled in the art can set other multi-stage alarms and / or multi-stage weight interlocks on the weighing instrument 32, the flow meter 21, the remote liquid level meter 11, the analyzer 40 and the like through non-creative labor, and the technical solutions formed thereby are within the protection scope of the present application.

[0070] Embodiment 3

[0071] The embodiment shows the process flow of the continuous preparation system of the sodium methoxide-methanol solution shown in the embodiment 1 under a specific working condition. It should be noted that the listed process flow is only a demonstration of a relatively optimal process, and does not limit the protection scope of the present application.

[0072] Embodiment 3.1

[0073] The methanol and the solid base are continuously input into the base preparation tank 10 (ID6000*H5500) to mix raw materials under the conditions of a reaction temperature of about 42°C and a pressure of 0.005 MPaG. The feeding flow rate of the solid base is 1.5 t / h, the feeding flow rate of the methanol is about 16 m 3 / h, the discharge flow rate of the circulating pump 70 is about 150 m 3 / h, the flow rate of the external circulating process liquid is about 133 m 3 / h, and the flow rate input into the downstream process is about 16 m 3 / h. The heat exchange area of the second cooler 80 is 93 m2, and the external circulating process liquid is stabilized at about 40°C. The sodium methoxide content of the circulating solution is about 9%wt through sampling analysis by the analyzer 40. The liquid seal tube 6 has a liquid seal height pressure greater than the tank pressure, which can be 2000 mm.

[0074] Embodiment 3.2

[0075] The methanol and the solid base are input into the base preparation tank 10 (ID4000*H3500) to mix under the conditions of an operating temperature of about 47°C and an operating pressure of 0.01 MPaG. The feeding flow rate of the solid base is 1 t / h, and the feeding flow rate of the methanol is about 10 m 3 / h. The discharge flow rate of the circulating pump is about 100 m 3 / h, the flow rate of the external circulating process liquid is about 90 m 3 / h, and the flow rate input into the downstream process is about 10 m 3The second cooler 80 has a heat exchange area of 60 m2, and the external circulation process liquid is stabilized at about 45°C. Sampling analysis shows that the sodium methoxide content of the circulation solution is about 9%wt. The liquid seal tube 6 has a liquid seal height pressure greater than the tank internal pressure, which can be selected as 2000 mm.

[0076] Example 3.3

[0077] The methanol and solid base enter the base preparation tank 10 (ID 4000*H 3500) to be mixed under the conditions of an operating temperature of about 52°C and an operating pressure of 0.015 MPaG, wherein the solid base feed flow rate is 1 t / h, and the methanol feed flow rate is about 15 m 3 / h. The circulation discharge pump flow rate is about 100 m 3 / h, wherein the external circulation process liquid is about 85 m 3 / h, and the flow rate input to the downstream process is about 15 m 3 / h. The second cooler 80 has a heat exchange area of 60 m2, and the external circulation process liquid is stabilized at about 50°C. Sampling analysis shows that the sodium methoxide content of the circulation solution is about 9%wt. The liquid seal tube 6 has a liquid seal height pressure greater than the tank internal pressure, which can be selected as 2000 mm.

[0078] It should be noted that the above is a further detailed description of the present application in combination with specific embodiments, and the specific implementation of the present application should not be limited to these descriptions; the size data of the present embodiment does not limit the technical solution, but only shows one specific working condition. For ordinary skilled persons in the technical field to which the present application belongs, some simple improvements and refinements can be made without departing from the concept of the present application, and all of them should be regarded as falling within the scope of the present application.

Claims

1. A device for continuously preparing a sodium methoxide methanol solution, characterized by comprising: The device comprises a base preparation tank (10), a liquid inlet pipe (20) connected to the top of the base preparation tank (10) for feeding methanol into the base preparation tank (10); a plurality of base buffer tanks (30) for temporarily storing and feeding solid base into the base preparation tank (10); the feeding port of the base buffer tank (30) is connected to the hinge conveyor through a pipeline, and the discharging port is connected to the top of the base preparation tank (10) through a pipeline; the top discharging port of the base preparation tank (10) is connected to the inlet of a first cooler (50) through a pipeline, and the outlet of the first cooler (50) is connected to the top of the base preparation tank (10) through a liquid seal device; the methanol vapor generated by the reaction heat of sodium methoxide preparation contains methanol and water generated by the reaction, which is fed into the first cooler (50) through a pipeline from the top discharging port of the base preparation tank (10), and after cooling, liquid-phase methanol and water vapor are obtained, the water vapor is discharged through a pipeline, and the liquid-phase methanol is returned to the base preparation tank (10); the lower discharging port of the base preparation tank (10) is connected to a circulating pump (70), the first branch (71) of the circulating pump (70) is divided into a plurality of return branches (81) through a second cooler (80), and the plurality of return branches (81) are respectively connected to the lower part of the base preparation tank (10); the second branch (72) of the circulating pump (70) is connected to a downstream process; the connection ports of the return branches (81) and the base preparation tank (10) are uniformly distributed along the circumference of the base preparation tank (10); the end of the return branch (81) extends into the base preparation tank (10) and is inclined downward at a certain angle.

2. The apparatus for continuous preparation of sodium methanolic solution according to claim 1, characterized in that, The number of base buffer tanks (30) is 2-4, and the connection ports of the base buffer tanks (30) and the base preparation tank (10) are uniformly distributed along the circumference of the base preparation tank (10).

3. The apparatus for continuous preparation of sodium methanolic solution according to claim 1, wherein The top discharging port of the base preparation tank (10) is connected to the first cooler (50) and a liquid storage tank in sequence through a pipeline; the outlet of the liquid storage tank is connected to the top of the base preparation tank (10) through a pipeline.

4. The apparatus for continuously preparing a sodium methoxide methanol solution according to claim 1, characterized by, A filter (90) or a plurality of filters (90) in parallel are arranged on the pipeline connected to the lower discharging port of the base preparation tank (10); a differential pressure meter (91) is arranged on the filter (90).

5. The apparatus for continuous preparation of sodium methanolic solution according to claim 1, wherein A flow meter (21) and a flow regulating valve (22) connected to the flow meter (21) are arranged on the liquid inlet pipe (20); the flow meter (21) and the flow regulating valve (22) are interlocked to control the feeding flow of methanol; A first shut-off valve (31) is arranged on the top of any base buffer tank (30), a weighing instrument (32) is arranged on the tank body, a second shut-off valve (34) and a rotary discharge valve (33) are arranged on the pipeline connected to the discharging port; the first shut-off valve (31), the second shut-off valve (34) and the rotary discharge valve (33) are interlocked with the weighing instrument (32) to control the feeding and discharging of the base buffer tank (30); A remote liquid level meter (11) is arranged on the base preparation tank (10), and the remote liquid level meter (11) is signal connected to the flow regulating valve (22) on the liquid inlet pipe (20). An analyzer (40) is arranged on the pipeline connected with the lower outlet of the alkali preparation tank (10), and the analyzer (40) is signal connected with the flow regulating valve (22) on the liquid inlet pipe (20).

6. A continuous process for the preparation of a solution of sodium methoxide in methanol using the apparatus according to any one of claims 1 to 5, characterized in that, The method comprises the following steps The reaction process: solid alkali input from the alkali buffer tank (30) reacts with methanol input from the liquid inlet pipe (20) in the alkali preparation tank (10) to generate sodium methoxide, and the sodium methoxide-methanol solution is taken out from the lower part of the alkali preparation tank (10) and delivered to the downstream process; The first cooling process: mixed gas generated by reaction heat is output from the top of the alkali preparation tank (10) and then cooled by the first cooler (50); the methanol steam caused by the heat of the sodium methoxide preparation reaction contains methanol and water generated by reaction, the methanol steam is input into the first cooler (50) through the pipeline from the top outlet of the alkali preparation tank (10), and after cooling, liquid phase methanol and water vapor are obtained, the water vapor is discharged through the pipeline, and the liquid phase methanol returns to the alkali preparation tank (10); The second cooling process: the outer circulation process liquid is output from the lower part of the alkali preparation tank (10), and after being cooled by the second cooler (80), the outer circulation process liquid is divided into multiple refluxes and returned to the lower part of the alkali preparation tank (10).

7. The continuous process for preparing sodium methoxide in methanol solution according to claim 6, characterized in that, In the reaction process, the mass ratio of the raw material solid alkali to methanol is 1:7.5-12, the operating temperature is 25-52°C, and the operating pressure is 5-15 kPaG.

8. The continuous process for preparing sodium methoxide in methanol solution according to claim 6, wherein The temperature of the first cooler (50) and the second cooler (80) is 40-50°C.

9. The continuous process for preparing sodium methoxide in methanol solution according to claim 6, wherein The volume ratio of the taken-out sodium methoxide-methanol solution to the outer circulation process liquid is 1:5-9.

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