System for preparing silicon fluoride by using fine powder of smelting furnace tail gas

Abstract

The utility model discloses a system of preparation silicon fluoride with the micro powder of the tail gas of the ore heating furnace belongs to the technical field of preparation silicon fluoride, including pickling kettle, be equipped with the micro powder feed pipe, acid liquid feed pipe and first discharge pipe on pickling kettle, first discharge pipe links to each other with the sedimentation tank, and the sedimentation tank is linked together with first sedimentation pipe and second sedimentation pipe through the sedimentation main pipe, and first sedimentation pipe and second sedimentation pipe link to each other with first drying kettle and second drying kettle respectively, be equipped with first inert gas inlet pipe, first tail gas pipe and second discharge pipe on first drying kettle, be equipped with second inert gas inlet pipe, second tail gas pipe and third discharge pipe on second drying kettle, and second discharge pipe and third discharge pipe link to each other with the reaction kettle feed pipe, and the reaction kettle feed pipe links to each other with the reaction kettle, be equipped with hydrofluoric acid feed pipe, first air pipe and fourth discharge pipe on the reaction kettle, and first air pipe links to each other with rectifying column, and be equipped with fluorosilane air pipe and rectifying column tail gas pipe on rectifying column.

Description

Technical Field

[0001] This invention belongs to the field of silicon fluoride preparation technology, specifically relating to a system for preparing silicon fluoride using micronized powder from the tail gas of a submerged arc furnace. Background Technology

[0002] The process of preparing silicon tetrafluoride (SiF) through fluorination using microsilica powder (silica content >90%, containing small amounts of metal oxides such as iron oxide, aluminum oxide, and calcium oxide, typically with a particle size of 0.1~0.3μm, appearing gray due to impurities) collected from industrial silicon flue gas is suitable for the production of chemical, semiconductor materials, and new energy battery raw materials. High-purity electronic-grade silicon tetrafluoride is a core material in semiconductor etching processes, used for the efficient removal of silicon-based materials (such as silicon nitride and tantalum silicide), and as a p-type dopant and silicon source for epitaxial deposition. In optical fiber manufacturing, silicon tetrafluoride is a key component in silicon-based semiconductor ion implantation processes, directly affecting fiber performance. In next-generation chip manufacturing processes, silicon tetrafluoride can be used to prepare low-dielectric-constant silicon dioxide thin films, solving the processing challenges of high aspect ratio insulating media. Silicon tetrafluoride is also widely used in photovoltaics, biomedicine, military aerospace, electrical, chemical materials, and many other fields.

[0003] Mainstream industrial methods: 1) Sulfuric acid method: Silicon tetrafluoride is produced by reacting sulfuric acid, fluoride salts, or fluorosilicates with silicon dioxide. Raw material costs are low, making it suitable for large-scale production. However, it produces many byproducts (such as calcium sulfate and hydrogen fluoride gas), requiring environmental protection facilities. The product purity is relatively low (requiring subsequent purification). 2) Hydrofluoric acid method: High-purity silicon powder reacts directly with anhydrous hydrofluoric acid at 250-300℃. It has a high conversion rate, but requires high-purity raw materials (silicon powder, hydrogen fluoride), and the equipment must be highly corrosion-resistant. The product contains HF and fluorosiloxane impurities, resulting in high purification costs. It is suitable for the production of high-value-added electronic-grade silicon tetrafluoride. 3) Fluorosilicate pyrolysis method: Fluorosilicates such as sodium hexafluorosilicate are pyrolyzed at 500-620℃. This method has high energy consumption and requires vacuum or inert gas protection. Utility Model Content

[0004] This invention addresses the problems in the prior art by providing a system for preparing silicon fluoride using micronized powder from submerged arc furnace (SAF) tail gas. The SAF tail gas micronized powder is fed into an acid washing vessel through a micronized powder feed pipe, followed by the addition of acid (dilute hydrochloric acid or dilute nitric acid) through an acid feed pipe. The SAF tail gas micronized powder undergoes impurity removal with the acid, and after impurity removal, it is discharged into a settling tank through a first discharge pipe. After settling, the SAF tail gas micronized powder is discharged into a first drying vessel and a second drying vessel through a main settling pipe, a first settling pipe, and a second settling pipe. The waste gas generated during drying is discharged through the first... The exhaust gas is discharged through the tail gas pipe and the second tail gas pipe. After drying, the first inert gas (such as nitrogen) is added through the first inert gas inlet pipe and the second inert gas inlet pipe. The dried ferroalloy tail gas powder is discharged into the reactor through the second and third discharge pipes through the inert gas. Then, it is added into the hydrofluoric acid through the hydrofluoric acid inlet pipe to carry out the fluorination reaction. The fluorosilane gas obtained from the reaction is discharged into the distillation column through the first gas outlet pipe for impurity removal. The fluorosilane product is discharged through the fluorosilane gas outlet pipe, and the fluorosilane gas containing impurities is discharged through the tail gas pipe of the distillation column.

[0005] This utility model is achieved through the following technical solution: A system for preparing silicon fluoride using tail gas from a submerged arc furnace includes an acid washing vessel. The acid washing vessel is equipped with a micro-powder feed pipe, an acid feed pipe, and a first discharge pipe. The first discharge pipe is connected to a settling tank. The settling tank is connected to a first settling pipe and a second settling pipe via a main settling pipe. The first and second settling pipes are respectively connected to a first drying vessel and a second drying vessel. The first drying vessel is equipped with a first inert gas inlet pipe, a first tail gas pipe, and a second discharge pipe. The second drying vessel is equipped with a second inert gas inlet pipe, a second tail gas pipe, and a third discharge pipe. The second and third discharge pipes are connected to a reactor feed pipe. The reactor feed pipe is connected to the reactor. The reactor is equipped with a hydrofluoric acid feed pipe, a first vent pipe, and a fourth discharge pipe. The first vent pipe is connected to a distillation column. The distillation column is equipped with a fluorosilane vent pipe and a distillation column tail gas pipe.

[0006] Preferably, the micro powder feed pipe is equipped with a micro powder feed valve, and the acid feed pipe is equipped with an acid feed valve; the first settling pipe and the second settling pipe are respectively equipped with a first settling liquid feed valve and a second settling liquid feed valve; the first inert gas inlet pipe, the first tail gas pipe and the second outlet pipe are respectively equipped with a first inert gas feed valve, a first tail gas valve and a second outlet valve; the second inert gas inlet pipe, the second tail gas pipe and the third outlet pipe are respectively equipped with a second inert gas feed valve, a second tail gas valve and a third outlet valve.

[0007] Preferably, a settling pressurization pump is installed on the settling manifold.

[0008] Preferably, the fourth discharge pipe is connected to the distillation vessel, and the distillation vessel is provided with a second vent pipe and a fifth discharge pipe.

[0009] Preferably, a compressor is installed on the first outlet pipe, and the compressor is connected to the hydrofluoric acid return pipe.

[0010] Preferably, the hydrofluoric acid reflux pipe is equipped with a cooler and a pipeline mixer, and the pipeline mixer is connected to the hydrofluoric acid feed pipe.

[0011] Preferably, the settling tank is provided with a gas collection hood at its upper end, the gas collection hood is provided with a settling tail gas pipe, and the pickling kettle is provided with a pickling tail gas pipe.

[0012] Preferably, the settling tail gas pipe, the first tail gas pipe, the second tail gas pipe, the distillation column tail gas pipe, and the acid washing tail gas pipe are all connected to the alkaline washing tower.

[0013] Preferably, the pickling tank, the first drying tank, the second drying tank, and the reaction tank are all equipped with a stirring device. The stirring device includes a stirring motor, a stirring shaft, and a stirring paddle. The output end of the stirring motor is connected to the stirring shaft, and the stirring paddle is mounted on the stirring shaft. The stirring shaft passes through the upper end of the pickling tank, the first drying tank, the second drying tank, or the reaction tank and enters the tank.

[0014] Preferably, the first drying vessel, the second drying vessel, and the distillation vessel are equipped with heating jackets. The heating jackets are equipped with steam inlet pipes and condensate outlet pipes.

[0015] Compared with the prior art, this utility model has the following advantages and beneficial effects: I. This utility model provides a system for preparing silicon fluoride using micronized powder from ferroelectric furnace tail gas. The micronized powder from the ferroelectric furnace tail gas is added to an acid washing kettle through a micronized powder feed pipe, followed by the addition of acid (dilute hydrochloric acid or dilute nitric acid) through an acid feed pipe. The micronized powder is purified by the acid, and after purification, it is discharged into a settling tank through a first discharge pipe. After settling, the micronized powder is discharged into a first drying kettle and a second drying kettle through a main settling pipe, a first settling pipe, and a second settling pipe. The waste gas generated during drying is discharged through the first tail gas pipe and the second... After drying, the tail gas is discharged through the tail gas pipe. The first inert gas (such as nitrogen) is added through the first inert gas inlet pipe and the second inert gas inlet pipe. The dried ferroalloy tail gas powder is discharged into the reactor through the second and third discharge pipes through the inert gas. Then, it is added into the hydrofluoric acid through the hydrofluoric acid inlet pipe to carry out the fluorination reaction. The fluorosilane gas obtained from the reaction is discharged into the distillation column through the first gas outlet pipe for impurity removal. The fluorosilane product is discharged through the fluorosilane gas outlet pipe, and the fluorosilane gas containing impurities is discharged through the tail gas pipe of the distillation column.

[0016] II. The present invention provides a system for preparing silicon fluoride using tail gas from a submerged arc furnace. The aqueous solution obtained from the reaction is discharged into a distillation kettle through a fourth discharge pipe. The hydrogen fluoride obtained from distillation is discharged into a compressor through a second gas outlet pipe. After compression, the hydrofluoric acid obtained is cooled by a cooler and then mixed by a pipeline mixer. The hydrofluoric acid is then returned to the reaction kettle for reuse through a hydrofluoric acid feed pipe. The aqueous solution obtained from distillation is discharged through a fifth discharge pipe.

[0017] III. This utility model provides a system for preparing silicon fluoride using micronized waste gas from a submerged arc furnace. This system features extremely low raw material costs: the micronized waste gas is a solid waste product with a stable source and significant cost advantages. High raw material activity: amorphous SiO2 exhibits good reactivity, resulting in energy saving and reduced consumption. Outstanding environmental benefits: it realizes the resource utilization of solid waste from silicon smelting, conforming to the concept of a circular economy. IV. This utility model provides a system for preparing silicon fluoride using micro powder from the tail gas of a submerged arc furnace. This system uses micro silicon powder from a submerged arc furnace to prepare silicon fluoride gas. Economic benefits: The value of waste micro silicon powder is increased, turning waste into treasure. Instruction manual illustrations Figure 1 This is a schematic diagram of the structure of this utility model; The components are as follows: 1. Pickling kettle; 2. Micro powder feed pipe; 3. Acid feed pipe; 4. First discharge pipe; 5. Settling tank; 6. Settling manifold; 7. First settling pipe; 8. Second settling pipe; 9. First drying kettle; 10. Second drying kettle; 11. First inert gas inlet pipe; 12. First tail gas pipe; 13. Second discharge pipe; 14. Second inert gas inlet pipe; 15. Second tail gas pipe; 16. Third discharge pipe; 17. Reactor feed pipe; 18. Reactor; 19. Hydrofluoric acid feed pipe; 20. First gas outlet pipe; 21. Fourth discharge pipe; 22. Distillation column; 23. Fluorosilane gas outlet pipe; 24. 25. Distillation column tail gas pipe; 26. Micro powder feed valve; 27. Acid feed valve; 28. First settling liquid feed valve; 29. ​​Second settling liquid feed valve; 30. First inert gas feed valve; 31. First tail gas valve; 32. Second discharge valve; 33. Second inert gas feed valve; 34. Third discharge valve; 35. Settling pressurization pump; 36. Distillation kettle; 37. Second gas outlet pipe; 38. Fifth discharge pipe; 39. Compressor; 40. Hydrofluoric acid return pipe; 41. Pipeline mixer; 42. Stirring device; 43. Heating jacket; 44. Cooler; 45. Pickling tail gas pipe. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0019] Example 1 like Figure 1As shown, a system for preparing silicon fluoride using micronized powder from the tail gas of a submerged arc furnace includes an acid pickling tank 1. The acid pickling tank 1 is equipped with a micronized powder feed pipe, an acid feed pipe, and a first discharge pipe 4. The first discharge pipe at the bottom of the tank is connected to a settling tank 5. The settling tank 5 is connected to a first settling pipe 7 and a second settling pipe 8 via a main settling pipe 6. The first settling pipe 7 and the second settling pipe 8 are respectively connected to a first drying tank 9 and a second drying tank 10. The first drying tank 9 is equipped with a first inert gas inlet pipe 11, a first tail gas pipe 12, and a second outlet pipe 10. The second drying vessel 10 is provided with a second inert gas inlet pipe 14, a second tail gas pipe 15, and a third outlet pipe 16. The second outlet pipe 13 and the third outlet pipe 16 are connected to the reactor inlet pipe 17. The reactor inlet pipe 17 is connected to the reactor 18. The reactor 18 is provided with a hydrofluoric acid inlet pipe 19, a first outlet pipe 20, and a fourth outlet pipe 21. The first outlet pipe 20 is connected to the distillation column 22. The distillation column 22 is provided with a fluorosilane outlet pipe 23 and a distillation column tail gas pipe 24.

[0020] Example 2 like Figure 1 As shown, a system for preparing silicon fluoride using micronized powder from the tail gas of a submerged arc furnace includes an acid pickling tank 1. The acid pickling tank 1 is equipped with a micronized powder feed pipe, an acid feed pipe, and a first discharge pipe 4. The first discharge pipe at the bottom of the tank is connected to a settling tank 5. The settling tank 5 is connected to a first settling pipe 7 and a second settling pipe 8 via a main settling pipe 6. The first settling pipe 7 and the second settling pipe 8 are respectively connected to a first drying tank 9 and a second drying tank 10. The first drying tank 9 is equipped with a first inert gas inlet pipe 11, a first tail gas pipe 12, and a second outlet pipe 10. The second drying vessel 10 is provided with a second inert gas inlet pipe 14, a second tail gas pipe 15, and a third outlet pipe 16. The second outlet pipe 13 and the third outlet pipe 16 are connected to the reactor inlet pipe 17. The reactor inlet pipe 17 is connected to the reactor 18. The reactor 18 is provided with a hydrofluoric acid inlet pipe 19, a first outlet pipe 20, and a fourth outlet pipe 21. The first outlet pipe 20 is connected to the distillation column 22. The distillation column 22 is provided with a fluorosilane outlet pipe 23 and a distillation column tail gas pipe 24.

[0021] The micro powder feed pipe is equipped with a micro powder feed valve 25, and the acid feed pipe is equipped with an acid feed valve 26; the first settling pipe 7 and the second settling pipe 8 are respectively equipped with a first settling liquid feed valve 27 and a second settling liquid feed valve 28; the first inert gas inlet pipe 11, the first tail gas pipe 12 and the second outlet pipe 13 are respectively equipped with a first inert gas feed valve 29, a first tail gas valve 30 and a second outlet valve 31; the second inert gas inlet pipe 14, the second tail gas pipe 15 and the third outlet pipe 16 are respectively equipped with a second inert gas feed valve 32, a second tail gas valve 33 and a third outlet valve 34.

[0022] The settling manifold 6 is equipped with a settling pressurization pump 35.

[0023] The fourth discharge pipe 21 is connected to the distillation vessel 36, and the distillation vessel 36 is provided with a second vent pipe 37 and a fifth discharge pipe 38.

[0024] The first outlet pipe 20 is equipped with a compressor 39, which is connected to the hydrofluoric acid return pipe 40.

[0025] The hydrofluoric acid reflux pipe 40 is equipped with a cooler 44 and a pipe mixer 41, and the pipe mixer 41 is connected to the hydrofluoric acid feed pipe 19.

[0026] The settling tank 5 is equipped with a gas collection hood at its upper end, and a settling tail gas pipe is installed on the gas collection hood; the pickling kettle 1 is equipped with a pickling tail gas pipe 45.

[0027] The settling tail gas pipe, the first tail gas pipe 12, the second tail gas pipe 15, the distillation column tail gas pipe 24, and the acid washing tail gas pipe 45 are all connected to the alkaline scrubbing tower. The tail gas is removed by alkaline solution in the alkaline scrubbing tower.

[0028] Each of the pickling tank 1, the first drying tank 9, the second drying tank 10, and the reaction tank 18 is equipped with a stirring device 42. The stirring device 42 includes a stirring motor, a stirring shaft, and a stirring paddle. The output end of the stirring motor is connected to the stirring shaft, and the stirring paddle is mounted on the stirring shaft. The stirring shaft passes through the upper end of the pickling tank 1, the first drying tank 9, the second drying tank 10, or the reaction tank 18 and enters the tank.

[0029] The first drying vessel 9, the second drying vessel 10, and the distillation vessel 36 are equipped with heating jackets 43. The heating jackets 43 are equipped with steam inlet pipes and condensate outlet pipes.

[0030] Among them, the pickling kettle 1, settling tank 5, first drying kettle 9, second drying kettle 10, reaction kettle 18, distillation column 22, micro powder feed valve 25, acid feed valve 26, first settling liquid feed valve 27, second settling liquid feed valve 28, first inert gas feed valve 29, first tail gas valve 30, second discharge valve 31, second inert gas feed valve 32, second tail gas valve 33, third discharge valve 34, settling pressurization pump 35, distillation kettle 36, compressor 39, pipeline mixer 41, stirring device 42, heating jacket 43 and cooler 44 are all existing technologies and will not be described in detail here.

[0031] Compared with the prior art, this utility model has the following advantages and beneficial effects: I. This utility model provides a system for preparing silicon fluoride using micronized powder from ferroelectric furnace tail gas. The micronized powder from the ferroelectric furnace tail gas is added to an acid washing tank 1 through a micronized powder feed pipe, followed by the addition of acid (dilute hydrochloric acid or dilute nitric acid) through an acid feed pipe. The micronized powder is purified by the acid, and after purification, it is discharged into a settling tank 5 through a first discharge pipe 4. After settling, the micronized powder is discharged into a first drying tank 9 and a second drying tank 10 through a main settling pipe 6, a first settling pipe 7, and a second settling pipe 8. The waste gas generated during drying is discharged through a first tail gas pipe 12 and a second tail gas pipe 15. After drying, the first inert gas (such as nitrogen) is added through the first inert gas inlet pipe 11 and the second inert gas inlet pipe 14. The dried ferroalloy tail gas powder is discharged into the reactor 18 through the second discharge pipe 13 and the third discharge pipe 16 via the inert gas. Then, it is added into the hydrofluoric acid through the hydrofluoric acid inlet pipe 19 to carry out the fluorination reaction. The fluorosilane gas obtained from the reaction is discharged into the distillation column 22 through the first gas outlet pipe 20 for impurity removal. The fluorosilane product is discharged through the fluorosilane gas outlet pipe 23, and the fluorosilane gas containing impurities is discharged through the tail gas pipe 24 of the distillation column.

[0032] II. The present invention provides a system for preparing silicon fluoride using tail gas powder from a submerged arc furnace. The aqueous solution obtained from the reaction is discharged into a distillation vessel 36 through a fourth discharge pipe 21. Hydrogen fluoride obtained from distillation is discharged into a compressor 39 through a second gas outlet pipe 37. After compression to obtain hydrofluoric acid, it is cooled by a cooler 44 and then mixed by a pipe mixer 41. The hydrofluoric acid is then returned to the reaction vessel 18 for reuse through a hydrofluoric acid feed pipe 19. The aqueous solution obtained from distillation is discharged through a fifth discharge pipe 38.

[0033] III. This utility model provides a system for preparing silicon fluoride using micronized waste gas from a submerged arc furnace. This system features extremely low raw material costs: the micronized waste gas is a solid waste product with a stable source and significant cost advantages. High raw material activity: amorphous SiO2 exhibits good reactivity, resulting in energy saving and reduced consumption. Outstanding environmental benefits: it realizes the resource utilization of solid waste from silicon smelting, conforming to the concept of a circular economy. IV. This utility model provides a system for preparing silicon fluoride using micro powder from the tail gas of a submerged arc furnace. This system uses micro silicon powder from a submerged arc furnace to prepare silicon fluoride gas. Economic benefits: The value of waste micro silicon powder is increased, turning waste into treasure.

[0034] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace, characterized in that: The system includes a pickling tank (1), which is equipped with a micro powder feed pipe (2), an acid feed pipe (3), and a first discharge pipe (4). The first discharge pipe (4) is connected to a settling tank (5). The settling tank (5) is connected to a first settling pipe (7) and a second settling pipe (8) via a settling manifold (6). The first settling pipe (7) and the second settling pipe (8) are respectively connected to a first drying tank (9) and a second drying tank (10). The first drying tank (9) is equipped with a first inert gas inlet pipe (11), a first tail gas pipe (12), and a second discharge pipe (13). The second drying tank (10) is equipped with a first inert gas inlet pipe (11), a first tail gas pipe (12), and a second discharge pipe (13). The drying vessel (10) is provided with a second inert gas inlet pipe (14), a second tail gas pipe (15) and a third discharge pipe (16). The second discharge pipe (13) and the third discharge pipe (16) are connected to the reactor inlet pipe (17). The reactor inlet pipe (17) is connected to the reactor (18). The reactor (18) is provided with a hydrofluoric acid inlet pipe (19), a first gas outlet pipe (20) and a fourth discharge pipe (21). The first gas outlet pipe (20) is connected to the distillation column (22). The distillation column (22) is provided with a fluorosilane gas outlet pipe (23) and a distillation column tail gas pipe (24).

2. The system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 1, characterized in that: The micro powder feed pipe (2) is provided with a micro powder feed valve (25), and the acid feed pipe (3) is provided with an acid feed valve (26); the first sedimentation pipe (7) and the second sedimentation pipe (8) are respectively provided with a first sedimentation liquid feed valve (27) and a second sedimentation liquid feed valve (28); the first inert gas inlet pipe (11), the first tail gas pipe (12) and the second discharge pipe (13) are respectively provided with a first inert gas feed valve (29), a first tail gas valve (30) and a second discharge valve (31); the second inert gas inlet pipe (14), the second tail gas pipe (15) and the third discharge pipe (16) are respectively provided with a second inert gas feed valve (32), a second tail gas valve (33) and a third discharge valve (34).

3. The system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 2, characterized in that: A settling pressurization pump (35) is installed on the settling manifold (6).

4. The system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 3, characterized in that: The fourth discharge pipe (21) is connected to the distillation vessel (36), and the distillation vessel (36) is provided with a second gas outlet pipe (37) and a fifth discharge pipe (38).

5. The system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 4, characterized in that: A compressor (39) is installed on the first outlet pipe (20), and the compressor (39) is connected to the hydrofluoric acid return pipe (40).

6. The system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 5, characterized in that: The hydrofluoric acid return pipe (40) is equipped with a cooler (44) and a pipe mixer (41), and the pipe mixer (41) is connected to the hydrofluoric acid inlet pipe (19).

7. The system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 6, characterized in that: The settling tank (5) is equipped with a gas collection hood at the upper end, and a settling tail gas pipe is provided on the gas collection hood; the pickling kettle (1) is equipped with a pickling tail gas pipe (45).

8. The system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 7, characterized in that: The settling tail gas pipe, the first tail gas pipe (12), the second tail gas pipe (15), the distillation column tail gas pipe (24), and the acid washing tail gas pipe (45) are all connected to the alkaline washing tower.

9. A system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 8, characterized in that: The pickling kettle (1), the first drying kettle (9), the second drying kettle (10) and the reaction kettle (18) are all equipped with stirring devices (42).

10. A system for preparing silicon fluoride using micronized powder from tail gas of a submerged arc furnace according to claim 9, characterized in that: Heating jackets (43) are provided on the first drying vessel (9), the second drying vessel (10), and the distillation vessel (36).

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