A continuous synthesis method and apparatus for liquid lithium hexafluorophosphate

Abstract

This invention discloses a continuous synthesis method and apparatus for liquid lithium hexafluorophosphate, comprising the following steps: S1, continuously adding lithium fluoride and an organic solvent into a mixing vessel to obtain lithium fluoride mother liquor, and continuously introducing a phosphorus pentafluoride mixed gas into a primary reactor; S2, continuously conveying the lithium fluoride mother liquor to the primary reactor for reaction with the phosphorus pentafluoride mixed gas; the primary reactor conveys the reacted material to a secondary reactor, while simultaneously conveying the unreacted phosphorus pentafluoride mixed gas to the secondary reactor for further reaction; S3, the secondary reactor transfers the unreacted gas out of the reaction system; the material obtained from the secondary reactor is continuously collected into a settling tank; S4, the top of the settling tank collects the synthesis liquid without lithium fluoride solids into a product receiving tank. This invention solves the synthesis efficiency bottleneck of traditional batch reactors and effectively improves the production capacity of liquid lithium hexafluorophosphate per unit time.

Description

Technical Field

[0001] This invention belongs to the field of lithium hexafluorophosphate preparation, specifically relating to a continuous synthesis method and apparatus for liquid lithium hexafluorophosphate. Background Technology

[0002] Lithium hexafluorophosphate (LiPF6) is a key raw material for new energy batteries. As of 2024, the global effective production capacity of LiPF6 reached 390,000 tons, with China accounting for 371,000 tons per year, ranking first in the world. Currently, more than 95% of LiPF6 is synthesized using anhydrous hydrofluoric acid solvent method. Although anhydrous hydrofluoric acid helps to accelerate the reaction process and increase the effective utilization rate of lithium fluoride, it leads to an excessively high hydrogen ion concentration in the final crystallized product. At the same time, because unreacted lithium fluoride is coated during the crystallization process, the content of insoluble matter increases. This not only leads to decreased product stability and increased potential corrosivity, but may also affect its actual application in areas such as lithium battery electrolytes. Therefore, some companies have begun to explore the organic solvent method. Currently, the production of liquid lithium hexafluorophosphate in the industry is all done by batch reactor operation, which requires manual switching of reactors and feeding. This results in low production efficiency. At the same time, the content of the reaction raw materials gradually decreases during the batch operation, and phosphorus pentafluoride will undergo side reactions with organic solvents, thus affecting the product quality.

[0003] Therefore, the applicant hopes to find a technical solution to solve the above technical problems. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a continuous synthesis method and apparatus for liquid lithium hexafluorophosphate, which continuously produces liquid lithium hexafluorophosphate product without subsequent deacidification, crystallization, and drying steps, and avoids pipeline blockage problems caused by the use of organic solvents. This solves the synthesis efficiency bottleneck of traditional batch reactors, effectively improving the production capacity of liquid lithium hexafluorophosphate per unit time. At the same time, by shortening the contact time between phosphorus pentafluoride and organic solvents, and by achieving stable control of operating temperature through continuous feeding and discharging into the two-stage reactor, the purity of the liquid lithium hexafluorophosphate product is effectively improved.

[0005] The technical solution adopted in this invention is as follows: A continuous synthesis method for liquid lithium hexafluorophosphate includes the following steps: S1. Lithium fluoride and organic solvent are continuously added to the mixing tank in a preset ratio to obtain lithium fluoride mother liquor, and phosphorus pentafluoride mixed gas is continuously introduced into the first-stage reactor. S2. The lithium fluoride mother liquor is continuously fed into the primary reactor to react with the phosphorus pentafluoride mixed gas; the primary reactor feeds the reacted material into the secondary reactor, and at the same time, the primary reactor feeds the unreacted phosphorus pentafluoride mixed gas into the secondary reactor to continue the reaction with the material fed into the secondary reactor from the primary reactor; S3. The secondary reactor transfers the unreacted gas out of the reaction system; the material obtained from the reaction in the secondary reactor is continuously extracted to a settling tank; S4. The settling tank transfers the unreacted excess lithium fluoride to one of the reactors to participate in the reaction; the top of the settling tank collects the synthesis liquid without lithium fluoride solids to the product receiving tank to obtain liquid lithium hexafluorophosphate.

[0006] Preferably, the organic solvent is selected from at least one of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, propylene carbonate, methyl propyl carbonate, and ethyl acetate.

[0007] Preferably, the mass ratio of lithium fluoride to organic solvent is 1:5-25.

[0008] Preferably, the phosphorus pentafluoride mixed gas is a mixture of phosphorus pentafluoride, hydrogen chloride, and hydrogen fluoride, or a mixture of phosphorus pentafluoride, hydrogen fluoride, and phosphorus trifluoride, wherein the phosphorus pentafluoride accounts for more than 30% of the mass content of the mixed gas.

[0009] Preferably, the operating temperature range of the mixing vessel is 5-40℃, and the operating pressure range is 0.01-0.1MPa.

[0010] Preferably, the operating temperature of the primary reactor is 20-30℃ and the operating pressure is controlled at 0.01-0.3MPa; the operating temperature of the secondary reactor is 20-30℃ and the operating pressure is controlled at 0.01-0.3MPa; preferably, the operating conditions of the primary reactor and the secondary reactor are the same.

[0011] Preferably, the feed mass ratio of lithium fluoride in the lithium fluoride mother liquor fed into the primary reactor to the phosphorus pentafluoride mixed gas fed into the primary reactor is controlled at 1:5-12.

[0012] Preferably, the liquid hexafluorophosphate contains 20-40% lithium hexafluorophosphate, and no subsequent deacidification, crystallization, and drying steps are required.

[0013] Preferably, a continuous synthesis apparatus used in the continuous synthesis method of liquid lithium hexafluorophosphate described above includes at least a mixing tank, a first transfer pump, a primary reactor, a second transfer pump, a secondary reactor, a third transfer pump, a settling tank, a product receiving tank, and a product transfer pump connected in sequence by pipelines. The secondary reactor is connected to a pipeline for conveying unreacted phosphorus pentafluoride mixed gas and a pipeline for discharging unreacted gas; and the pipeline for conveying unreacted phosphorus pentafluoride mixed gas is connected to the primary reactor. The primary reactor is connected to a phosphorus pentafluoride mixed gas feed pipeline; The primary and secondary reactors are either tubular reactors or batch reactors. Preferably, the mixing tank, the primary reactor, and the secondary reactor are all equipped with high-speed agitators, and the bottom of the settling tank is equipped with a low-speed agitator. Preferably, the primary reactor and the second transfer pump, and the secondary reactor and the third transfer pump are each provided with a separate synthesis liquid material circulation pipeline.

[0014] Preferably, the primary reactor and / or the secondary reactor are equipped with cooling coils, which are internal coils and / or external tracing pipes; or a circulating heat exchanger is installed on the synthesis liquid material circulation pipeline between the second transfer pump and the primary reactor; or a circulating heat exchanger is installed on the synthesis liquid material circulation pipeline between the third transfer pump and the secondary reactor.

[0015] The continuous synthesis method and apparatus for liquid lithium hexafluorophosphate proposed in this application innovatively proposes the following: a phosphorus pentafluoride mixed gas is continuously fed into a primary reactor; a lithium fluoride organic solvent mixture mother liquor is continuously fed into the primary reactor; the material obtained from the reaction in the primary reactor is fed into a secondary reactor to react with the incompletely reacted phosphorus pentafluoride mixed gas fed from the primary reactor to the secondary reactor; the liquid hexafluorophosphate reactant is continuously collected from the secondary reactor to a settling tank, and the liquid lithium hexafluorophosphate product is continuously collected from the top of the settling tank. Subsequent deacidification, crystallization, and drying steps are unnecessary, and pipeline blockage problems caused by the use of organic solvents are avoided. This solves the synthesis efficiency bottleneck of traditional batch reactors, effectively increasing the production capacity of liquid lithium hexafluorophosphate per unit time. Simultaneously, by shortening the contact time between phosphorus pentafluoride and the organic solvent, and through continuous feeding and discharging into the two-stage reactors, stable temperature control is achieved, effectively improving the purity of the liquid lithium hexafluorophosphate product. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a continuous liquid lithium hexafluorophosphate synthesis apparatus according to a specific embodiment of this application. Detailed Implementation

[0017] Please see Figure 1 As shown, this embodiment proposes a continuous synthesis apparatus for liquid lithium hexafluorophosphate, which includes at least a mixing tank V100, a first transfer pump P100, a primary reactor F200-1, a second transfer pump P200, a secondary reactor F200-2, a third transfer pump P300, a settling tank V400, a product receiving tank V300, and a product transfer pump P400 connected in sequence by pipelines. The secondary reactor F200-2 is connected to both a pipeline for conveying the incompletely reacted phosphorus pentafluoride mixed gas and a pipeline for discharging the incompletely reacted gas. The pipeline for conveying the incompletely reacted phosphorus pentafluoride mixed gas is connected to the primary reactor F200-1. The primary reactor F200-1 is connected to a feed pipeline for the phosphorus pentafluoride mixed gas. Both the primary reactor F200-1 and the secondary reactor F200-2 are tubular reactors. Preferably, in this embodiment, the mixing tank V100, the primary reactor F200-1, and the secondary reactor F200-2 are all equipped with high-speed agitators to achieve efficient mixing of materials, and the bottom of the settling tank V400 is equipped with a low-speed agitator to prevent solid accumulation at the bottom of the settling tank V400. Preferably, in this embodiment, a separate synthetic liquid material circulation pipeline is provided between the primary reactor F200-1 and the second transfer pump P200, and between the secondary reactor F200-2 and the third transfer pump P300; by setting up the synthetic liquid material circulation pipeline, the material in each reactor is mixed more evenly, and the pipeline is also prevented from being blocked.

[0018] It should be noted that in this embodiment, the settling tank V400 serves as the product extraction end and is directly connected to the receiving tank V300. In other embodiments, a third-stage reactor may be further provided as needed, and its connection with the settling tank V400 is the same as that of the second-stage reactor F200-2. The settling tank serves as the product extraction end and is connected to the receiving tank V300. More stages of reactors may also be provided with reference to this structural connection method. This embodiment does not impose a unique limitation on this.

[0019] Preferably, in this embodiment, the mixing tank V100 is provided with an automatic lithium fluoride weighing inlet and an organic solvent inlet to achieve continuous and accurate feeding into the mixing tank V100. Preferably, in this embodiment, both the primary reactor F200-1 and the secondary reactor F200-2 are equipped with jackets (i.e., cooling coils with external tracing pipes; in other embodiments, the cooling coils may also have an internal coil structure) to meet the heat extraction requirements, in order to maintain the operating temperature in each stage of the reactor. It should be further noted that in other embodiments, a circulating heat exchanger is installed on the synthesis liquid material circulation pipeline between the second transfer pump P200 and the primary reactor F200-1; and / or a circulating heat exchanger is installed on the synthesis liquid material circulation pipeline between the third transfer pump P300 and the secondary reactor F200-2.

[0020] Preferably, in this embodiment, an online material purity detection instrument is installed at the discharge end of the settling tank V400 (in other embodiments, it can be installed at the discharge end of the last stage reactor) to monitor the reaction progress. The online material purity detection instrument is characterized by detecting the lithium fluoride content or lithium hexafluorophosphate content in the reaction material at the outlet end. In this embodiment, the secondary reactor F200-2 is connected to the settling tank V400 for solid-liquid separation (in other embodiments, it can be set at the discharge end of the last stage reactor). This separates and removes unreacted lithium fluoride solids from the reactants, which not only avoids pipeline blockage but also improves the purity of the liquid lithium hexafluorophosphate product. More preferably, in this embodiment, the lithium fluoride solids separated by the settling tank V400 can be directly returned to the primary reactor F200-1 or the secondary reactor F200-2 to participate in the reaction. More preferably, they are directly returned to the secondary reactor F200-2 to participate in the reaction. In other embodiments, when each stage of the reactor uses a batch reactor (preferably, an agitator can be provided for material mixing; more preferably, the agitator is configured with an upward and downward pressing function), the gas feed inlet is located at the bottom of the batch reactor, or it can be located at the top of the batch reactor, and is inserted into the bottom of its corresponding batch reactor through an inner tube; more preferably, holes can be made in the inner tube to allow the gas feed to exit evenly from each hole; more preferably, the inner tube is annular. Using the liquid lithium hexafluorophosphate continuous synthesis apparatus described above, this embodiment also proposes a liquid lithium hexafluorophosphate continuous synthesis method, including the following operation steps: S1. Lithium fluoride and an organic solvent are continuously added to a mixing tank V100 according to a preset ratio to obtain a lithium fluoride mother liquor. The phosphorus pentafluoride mixed gas is then continuously introduced into a primary reactor F200-1. Preferably, in this embodiment, the organic solvent is selected from at least one of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, methyl propyl carbonate, and ethyl acetate. Preferably, the mass ratio of lithium fluoride to the organic solvent is 1:5-25. Preferably, the phosphorus pentafluoride mixed gas is a mixture of phosphorus pentafluoride, hydrogen chloride, and hydrogen fluoride, which can be directly derived from phosphorus pentafluoride. The production line (in other embodiments, it can also be a mixture of phosphorus pentafluoride, hydrogen fluoride, and phosphorus trifluoride, or a mixture of phosphorus pentafluoride, hydrogen chloride, hydrogen fluoride, and phosphorus trifluoride; it should be noted that the "phosphorus pentafluoride mixture" involved in this application may also contain other impurities, and can also be a mixture of phosphorus pentafluoride obtained by other processes and other one or more components. These are all within the scope of this application and are not intended as special limitations on this application), wherein phosphorus pentafluoride accounts for more than 30% by mass in the mixture; S2. The lithium fluoride mother liquor is continuously fed into the primary reactor F200-1 to react with the phosphorus pentafluoride mixed gas. The reacted material from the primary reactor F200-1 is then fed into the secondary reactor F200-2. Simultaneously, the unreacted phosphorus pentafluoride mixed gas from the primary reactor F200-1 is fed into the secondary reactor F200-2 to continue reacting with the material from the primary reactor F200-1. Preferably, in this embodiment, the feed mass ratio of lithium fluoride in the lithium fluoride mother liquor fed into the primary reactor F200-1 to the phosphorus pentafluoride mixed gas fed into the secondary reactor F200-1 is controlled at 1:5-12. Preferably, in this embodiment, the feed mass ratio of lithium fluoride in the lithium fluoride mother liquor fed into the primary reactor F200-1 to the phosphorus pentafluoride mixed gas fed into the secondary reactor F200-1 is controlled at 1:1.5-4.8. S3, the secondary reactor F200-2 transfers the unreacted gas out of the reaction system; the material obtained from the reaction in the secondary reactor F200-2 is continuously extracted to the settling tank V400; S4. Settling tank V400 transports unreacted excess lithium fluoride to secondary reactor F200-2 to participate in the reaction; the top of settling tank V400 collects the synthesis liquid without lithium fluoride solids to product receiving tank V300 to obtain liquid lithium hexafluorophosphate, realizing the continuous collection of liquid hexafluorophosphate product. Preferably, the content of lithium hexafluorophosphate in liquid hexafluorophosphate is 20-40%.

[0021] Preferably, in this embodiment, the operating temperature range of the mixing vessel V100 is 5-40℃, and the operating pressure range is 0.01-0.1MPa; the operating temperature of the primary reactor F200-1 is 20-30℃, and the operating pressure is controlled at 0.01-0.3MPa, more preferably 0.05-0.15MPa; the operating temperature of the secondary reactor F200-2 is 20-30℃, and the operating pressure is controlled at 0.01-0.3MPa; more preferably, in this embodiment, the operating temperature of the secondary reactor F200-2 is the same as that of the primary reactor F200-1, and their operating pressures are also equal.

[0022] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0023] Based on the above-described implementation schemes, this application further proposes the following specific embodiments: It should be noted that, unless otherwise specified, the raw materials used in the following specific embodiments of the present invention are all commercially available products. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] Example 1: Based on the above implementation scheme, Example 1 proposes the following specific implementation scheme: Please refer to the above. Figure 1 As shown, a continuous liquid lithium hexafluorophosphate synthesis apparatus includes a mixing tank V100, a first transfer pump P100, a primary reactor F200-1, a second transfer pump P200, a secondary reactor F200-2, a third transfer pump P300, a settling tank V400, a product receiving tank V300, and a product transfer pump P400, all connected sequentially by pipelines. Both the primary reactor F200-1 and the secondary reactor F200-2 are tubular reactors, with specific specifications as follows: The mixing vessel V100 has the specifications of DN1400*1200, an operating temperature of 30℃, and an operating pressure of 0.02MPa; Both the primary reactor F200-1 and the secondary reactor F200-2 have a specification of DN200*1500, and both operate at a temperature of 25℃, a jacket temperature of 5℃, and an operating pressure of 0.1MPa. The settling tank V400 has a specification of DN250*2000, a conical bottom (and is equipped with a low-speed agitator), and operates at room temperature. The pressure is the same as that of the secondary reactor F200-2. The receiving tank V300 has a specification of DN400*650 and operates under normal temperature and pressure conditions. The specific process for the continuous synthesis of liquid lithium hexafluorophosphate is as follows: Lithium fluoride and ethyl methyl carbonate are fed into mixing reactor V100 at a ratio of 8% by mass, and lithium fluoride mother liquor is prepared by stirring. Liquid lithium hexafluorophosphate mother liquor is pre-pumped into primary reactor F200-1. A mixed gas composed of phosphorus pentafluoride, hydrogen chloride, and hydrogen fluoride (the mass ratio of phosphorus pentafluoride:hydrogen chloride:hydrogen fluoride in this mixed gas is 40.75:59.08:0.157) is directly pumped from other phosphorus pentafluoride production line processes into primary reactor F200-1 at a rate of 9.4 kg / h to react with the lithium fluoride mother liquor transferred from mixing reactor V100 at a rate of 10 kg / h. The unreacted mixed gas is then fed into... The liquid lithium hexafluorophosphate synthesis solution transferred from the primary reactor F200-1 to the secondary reactor F200-2 at a rate of 10 kg / h is reacted. The unreacted gases (mainly hydrogen chloride) are treated in the tail gas recovery section. The material obtained from the reaction in the secondary reactor F200-2 is continuously collected into the settling tank V400. Liquid lithium hexafluorophosphate is continuously collected from the top of the settling tank V400 and tested. The mass content of lithium hexafluorophosphate is 30.03%, and the mass content of hydrogen fluoride is 0.0025%. The unreacted excess lithium fluoride in the settling tank V400 is transported to the secondary reactor F200-2 to participate in the reaction.

[0025] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0026] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A continuous synthesis method for liquid lithium hexafluorophosphate, characterized in that, The following steps are included: S1. Lithium fluoride and organic solvent are continuously added to the mixing tank (V100) according to a preset ratio to obtain lithium fluoride mother liquor, and phosphorus pentafluoride mixed gas is continuously introduced into the primary reactor (F200-1). S2. The lithium fluoride mother liquor is continuously fed into the primary reactor (F200-1) to react with the phosphorus pentafluoride mixed gas; the primary reactor (F200-1) feeds the reacted material into the secondary reactor (F200-2), while the primary reactor (F200-1) feeds the incompletely reacted phosphorus pentafluoride mixed gas into the secondary reactor (F200-2) to continue the reaction with the material fed into the secondary reactor (F200-2) from the primary reactor (F200-1); S3. The secondary reactor (F200-2) transfers the unreacted gas out of the reaction system; the material obtained from the reaction in the secondary reactor (F200-2) is continuously extracted to the settling tank (V400). S4. The settling tank (V400) transports the unreacted excess lithium fluoride to one of the reactors to participate in the reaction; the top of the settling tank (V400) collects the synthesis liquid without lithium fluoride solids to the product receiving tank (V300) to obtain liquid lithium hexafluorophosphate.

2. The continuous synthesis method of liquid lithium hexafluorophosphate according to claim 1, characterized in that, The organic solvent is selected from at least one of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, methyl propyl carbonate, and ethyl acetate.

3. The continuous synthesis method of liquid lithium hexafluorophosphate according to claim 1, characterized in that, The mass ratio of lithium fluoride to organic solvent is 1:5-25.

4. The continuous synthesis method of liquid lithium hexafluorophosphate according to claim 1, characterized in that, The phosphorus pentafluoride mixed gas is a mixture of phosphorus pentafluoride, hydrogen chloride, and hydrogen fluoride, or a mixture of phosphorus pentafluoride, hydrogen fluoride, and phosphorus trifluoride, wherein the phosphorus pentafluoride accounts for more than 30% of the mass content of the mixed gas.

5. The continuous synthesis method of liquid lithium hexafluorophosphate according to claim 1, characterized in that, The operating temperature range of the mixing vessel (V100) is 5-40℃, and the operating pressure range is 0.01-0.1MPa.

6. The continuous synthesis method of liquid lithium hexafluorophosphate according to claim 1, characterized in that, The operating temperature of the primary reactor (F200-1) is 20-30℃, and the operating pressure is controlled at 0.01-0.3MPa; The operating temperature of the secondary reactor (F200-2) is 20-30℃, and the operating pressure is controlled at 0.01-0.3MPa; preferably, the operating conditions of the primary reactor (F200-1) and the secondary reactor (F200-2) are the same.

7. The continuous synthesis method of liquid lithium hexafluorophosphate according to claim 1, characterized in that, The feed mass ratio of lithium fluoride in the lithium fluoride mother liquor fed into the primary reactor (F200-1) to the phosphorus pentafluoride mixed gas fed into the primary reactor (F200-1) is controlled at 1:5-12.

8. The continuous synthesis method of liquid lithium hexafluorophosphate according to claim 1, characterized in that, The liquid hexafluorophosphate contains 20-40% lithium hexafluorophosphate and requires no subsequent deacidification, crystallization, or drying steps.

9. A continuous synthesis apparatus used in the continuous synthesis method of liquid lithium hexafluorophosphate according to any one of claims 1-8, characterized in that, It includes at least the following components connected in sequence via pipelines: mixing tank (V100), first transfer pump (P100), primary reactor (F200-1), second transfer pump (P200), secondary reactor (F200-2), third transfer pump (P300), settling tank (V400), product receiving tank (V300), and product transfer pump (P400). The secondary reactor (F200-2) is connected to a pipeline for conveying unreacted phosphorus pentafluoride mixed gas and a pipeline for discharging unreacted gas; and the pipeline for conveying unreacted phosphorus pentafluoride mixed gas is connected to the primary reactor (F200-1). The primary reactor (F200-1) is connected to a phosphorus pentafluoride mixed gas feed pipeline; The primary reactor (F200-1) and the secondary reactor (F200-2) are tubular reactors or batch reactors; Preferably, the mixing tank (V100), the primary reactor (F200-1), and the secondary reactor (F200-2) are all equipped with high-speed agitators, and the bottom of the settling tank (V400) is equipped with a low-speed agitator. Preferably, the primary reactor (F200-1) and the second transfer pump (P200), and the secondary reactor (F200-2) and the third transfer pump (P300) are each provided with a separate synthesis liquid material circulation pipeline.

10. The continuous synthesis apparatus used in the continuous synthesis method of liquid lithium hexafluorophosphate according to claim 9, characterized in that, The primary reactor (F200-1) and / or the secondary reactor (F200-2) are equipped with cooling coils, which are internal coils and / or external ducts; or a circulating heat exchanger is installed on the synthesis liquid material circulation pipeline between the second transfer pump (P200) and the primary reactor (F200-1); or a circulating heat exchanger is installed on the synthesis liquid material circulation pipeline between the third transfer pump (P300) and the secondary reactor (F200-2).

Images