PENTACHLORODISILANE PRODUCTION METHOD AND PENTACHLORODISILANE PRODUCED BY SAME

Abstract

[Problem] To provide a novel production method for pentachlorodisilane and to obtain pentachlorodisilane having a purity of 90 mass % or more by carrying out this production method.

[Solution] A production method provided with: a high-temperature reaction step in which a raw material gas containing vaporized tetrachlorosilane and hydrogen is reacted at a high temperature in order to obtain a reaction product gas containing trichlorosilane; a pentachlorodisilane generation step in which the reaction product gas obtained in the high-temperature reaction step is brought into contact with a cooling liquid obtained by circulative cooling of a condensate that is generated by cooling the reaction product gas, the reaction product gas is quickly cooled, and pentachlorodisilane is generated within the condensate; and a recovery step in which the generated pentachlorodisilane is recovered.

Claims

1. A pentachlorodisilane production method characterized by being provided with a high temperature reaction step for obtaining a reaction product gas including trichlorosilane by reacting a raw material gas including vaporized tetrachlorosilane and hydrogen at a high temperature, a pentachlorodisilane generation step for generating pentachlorodisilane in a condensate by contacting the reaction product gas obtained in the high temperature reaction step with a coolant obtained by circulative cooling the condensate generated by cooling the reaction product gas and rapidly cooling same, and a recovery step for recovering the generated pentachlorodisilane.

2. The pentachlorodisilane production method of claim 1 characterized by, in the pentachlorodisilane generation step, adding additional tetrachlorosilane to the coolant and/or the condensate, recovering the coolant and/or the condensate as an extracted liquid extracted outside a circulation system, and adjusting the concentration or mass generated per unit time of pentachlorodisilane included in the extracted liquid.

3. The pentachlorodisilane production method of claim 2 characterized by, in the recovery step, distilling the extracted liquid and obtaining pentachlorodisilane having purity of at least 90 mass %.

4. The pentachlorodisilane production method of claim 2 characterized by, in the recovery step, recovering the extracted liquid in a distillation device provided with a heating device, generating a evaporation gas by heating, introducing the gas to a concentrating column, removing trichlorosilane and tetrachlorosilane, and obtaining a liquid containing pentachlorodisilane.

5. The pentachlorodisilane production method of claim 4 characterized by further distilling the liquid containing pentachlorodisilane obtained from the concentrating column and obtaining pentachlorodisilane having purity of at least 90 mass %.

6. Pentachlorodisilane having purity of at least 90 mass % produced by the method of claim 5.

Description

SIMPLE EXPLANATION OF THE DRAWINGS

[0020] [FIG. 1] A flowchart to explain the pentachlorodisilane production method according to the present invention.

[0021] [FIG. 2] A flowchart illustrating distillation equipment combining two-stage distillation columns as an example of equipment used in the recovery step of the present invention.

MODES FOR CARRYING OUT THE INVENTION

[0022] One example of the pentachlorodisilane production method according to the present invention shall be explained, using the schematic drawing illustrated in FIG. 1.

[0023] The schematic drawing in FIG. 1 includes a vaporizer 10 for vaporizing a tetrachlorosilane raw material, a preheater 20 for preheating a raw material gas including the vaporized tetrachlorosilane raw material and hydrogen, a reactor 30 for reacting the preheated raw material gas at a temperature range of 700-1400° C. and obtaining a reaction product gas, a rapid cooling tower 40 for cooling the reaction product gas to a temperature preferably no more than 200° C., more preferably to a temperature range of 30-60° C., and obtaining condensate including pentachlorodisilane, and a recovery device 50 for recovering the pentachloridisilane from the condensate. Furthermore, a pump 43 for circulating the condensate, a cooling device 44 for cooling the condensate, forming a coolant, and a spray nozzle 42 for blowing the coolant into the rapid cooling tower may be provided. In addition, in the present invention, additional tetrachlorosilane may be added to the circulated coolant at the position indicated by 49 by using equipment having a mechanism capable of adjusting the addition speed. Furthermore, in the present invention, it is possible to use equipment having a mechanism capable of adjusting the extraction speed to extract the circulated condensate at the position indicated by 45.

[0024] In general, the production method of the present invention is preferably provided with a condenser 60 for condensing trichlorosilane and tetrachlorosilane from the cooled and uncondensed reaction product gas, a tank 70 for temporarily storing condensate removed from condenser 60 and low-boiling point substances removed from recovery device 50, and a distillation column 80 for fractionally distilling trichlorosilane and tetrachlorosilane from stored liquid drawn from tank 70. Recovery device 50 also functions as a single still 90 that vaporizes pentachlorodisilane and tetrachlorosilane from the condensate obtained in rapid cooling tower 40 and separates from the unvaporized portion and is preferably equipped with a concentrating column 100 that separates pentachlorodisilane provided from single still 90 from other low-boiling point substances. In an example of the present production method, vaporizer 10, preheater 20, and reactor 30 constitute a high temperature reaction step and subsequent rapid cooling tower 40, pump 43, cooling device 44, and spray nozzle 42 are a device constituting a rapid cooling step (pentachlorodisilane generating step).

[0025] Each device shall be explained in further detail below.

[0026] <Vaporizer>

[0027] Vaporizer 10 is a device for vaporizing the raw material tetrachlorosilane and, after being released from vaporizer 10, the vaporized tetrachlorosilane is mixed with hydrogen and supplied to preheater 20.

[0028] It is desirable that the tetrachlorosilane raw liquid supplied to vaporizer 10 be high purity tetrachlorosilane, but small amounts of silanes having boiling points higher than that of tetrachlorosilane may be mixed therein. However, such high-boiling point substances accumulate as an unvaporized portion at a bottom section of vaporizer 10 and prevent the vaporization of tetrachlorosilane, so it is preferable that vaporizer 10 have a structure so as to be capable of removing the unvaporized portion collected at the bottom section of vaporizer 10 in batches or continuously. The removed unvaporized portion can be supplied to distillation device 90 in recovery device 50 to recover industrially usable tetrachlorosilane, pentachlorodisilane, etc. that was expelled at the same time.

[0029] The heating temperature for the raw material tetrachlorosilane in vaporizer 10 can be set to 60-150° C. under atmospheric pressure, preferably to 60-120° C. At this temperature range, tetrachlorosilane can be adequately vaporized without vaporizing high-boiling point substances such as pentachlorodisilane. Naturally, if vaporizer 10 is a type capable of adjusting the internal pressure, the optimum temperature for vaporizing tetrachlorosilane can vary from the above temperature range in accordance therewith.

[0030] <Preheater>

[0031] The raw material tetrachlorosilane vaporized in vaporizer 10 is mixed with hydrogen gas and supplied as a raw material gas to reactor 30, which will be discussed below, but before being sent to reactor 30, the gas is heated in preheater 20 so as to approach the temperature inside reactor 30. By doing so, the difference between the temperature of the mixed gas and the temperature inside reactor 30 is lessened and it is possible to increase the conversion rate in reactor 30 without generating temperature irregularities therein as well as to protect reactor 30 from local thermal stress concentrations. Further, the trichlorosilane generated by the reaction between tetrachlorosilane and hydrogen and being at a state of thermal equilibrium can prevent return to the tetrachlorosilane due to temperature reductions caused by flows of the raw material gas. The mixing ratio of tetrachlorosilane and hydrogen gas can be set to, for example, a molar ratio of 1:1-1:2.

[0032] <Reactor>

[0033] Reactor 30 is equipped with a reactor vessel 31, a heater 32 having a long length arranged so as to surround the outer side of reactor vessel 31, and an external cylinder vessel 33 housing reactor vessel 31 and heater 32. By the outer walls of reactor vessel 31 being heated by heater 32 the mixed gas of tetrachlorosilane and hydrogen is reacted inside reactor vessel 31 at a high temperature of about 700-1,400° C., by which the generation of trichlorosilane mainly progresses. This reaction is a thermal equilibrium reaction and silylene, monochlorosilane, dichlorosilane, tetrachlorosilane, hydrogen, hydrogen chloride, and the like are in a state of coexistence. Furthermore, it can be thought that, due to reactions of these substances with one another, hexachlorodisilane and pentachlorodisilane, which the present invention is directed to, are generated, for example, by reaction of silylene and trichlorosilane, in this state of coexistence and are steadily present.

[0034] <Reactor Vessel>

[0035] Reactor vessel 31 is an approximately cylindrical vessel for reacting the raw material tetrachlorosilane and hydrogen in a high temperature environment, having a raw material gas inlet for introducing the raw material gas and a reaction product gas extraction outlet for discharging reaction product gas. In the present embodiment, reactor vessel 31 has a structure wherein the raw material gas inlet is provided at the center of a bottom section of reactor vessel 31 and the reaction product gas extraction outlet is provided on an upper side wall of reactor vessel 31. An extraction pipe 34 is inserted in the reaction product gas extraction outlet and the reaction product gas is expelled to the outside of reactor 30. When housing reactor vessel 31, outer cylindrical vessel 33 is provided with a raw material gas inlet opening and a reaction product gas extraction opening at positions corresponding respectively to the raw material gas inlet and reaction product gas extraction outlet on reactor vessel 31. A connection means connected to rapid cooling tower 40 is provided to the reaction product gas extraction opening. Extraction pipe 34 is a pipe member connected, through the reaction product gas extraction opening in outer cylindrical vessel 33, to the reaction gas extraction outlet in reactor vessel 31 and the reaction product gas that includes trichlorosilane generated in reactor vessel 31 is expelled from extraction pipe 34 and supplied to rapid cooling tower 40.

[0036] <Rapid Cooling Tower>

[0037] Rapid cooling tower 40 is provided with a cylindrical metal vessel 41, a spraying means to spray the reaction product gas with coolant in metal vessel 41, that is, spray nozzle 42 that separates the coolant into fine droplets, pump 43 that extracts the condensate also collected at the bottom of metal vessel 41 and circulates it to spray nozzle 42, cooling device 44 that cools the condensate, and a pipeline 45 that extracts a portion of the condensate and sends it to recovery device 50 (single still 90).

[0038] The middle of pipeline 45 can be provided with a mechanism capable of adjusting the extraction speed of the condensate, such as, for example, a control valve. A side wall of rapid cooling tower 40 is provided with reaction product gas extraction pipe 34 to connect to reactor 30. Spray nozzle 42 is arranged dose to an upper part of the reaction product gas inlet opening so as to be capable of spraying coolant toward the reaction product gas introduced to rapid cooling tower 40. Further, a pipe is connected to an apex part of rapid cooling tower 40 to supply uncondensed gas of the reaction product gas that is in a gas state even after cooling to condenser 60, which will be discussed below. In the example in FIG. 1, a packing layer 46 is provided at a part higher than a rapid cooling part of rapid cooling tower 40 and a pipe 47 that supplies coolant is provided to further cool rapidly cooled reaction product gas that passes through packing layer 46.

[0039] Furthermore, in order to prevent one-sided flow of the coolant supplied from pipe 47, a dispersion panel is provided neighboring a lower part of pipe 47. In addition, supplying coolant from pipe 47 also has the effect of preventing the corrosion of metal vessel 41 and packing layer 46 by high temperature reaction gas. Furthermore, by changing the supply speed of the coolant from pipe 47, the amount of condensed and liquefied reaction gas changes and it is possible to maintain a constant amount of circulated liquid in the rapid cooling tower. That is, when the amount of coolant or condensate circulated in the rapid cooling tower is reduced, the amount of coolant in pipe 47 may be increased so as to increase the condensed gas and conversely, when the amount of the coolant or the condensate in the rapid cooling tower is increased, the amount of coolant from pipe 47 may be reduced so as to reduce the condensate gas.

[0040] The condensate is a liquid collected at the bottom part of metal vessel 41 in rapid cooling tower 40, extracted via a tank 48, continuously circulated, and cooled by cooling device 44 to be made into the coolant, and, while being a mixed liquid formed by mainly containing tetrachlorosilane and trichlorosilane, tetrachlorosilane for addition can be further added to the coolant in the present invention. In order to do so, a tetrachlorisilane for addition inlet pipe 49 is connected to the base of spray nozzle 42. Inlet pipe 49 has a control valve or the like in the middle and it is possible to adjust the supply speed thereof. The added tetrachlorosilane may be obtained from anywhere, for example, tetrachlorisilane drawn from distillation column 80, which will be discussed below, may be used.

[0041] The amount of tetrachlorosilane added in the coolant is preferably 10-10,000 L/h per 1,000 L/h of the raw tetrachlorosilane (prior to vaporization), more preferably, 10-5,000 L/h, and even more preferably, 100-500 L/h. If the addition speed of the tetrachlorosilane is increased, the concentration or mass generated per unit time of the pentachlorodisilane in the condensate (extracted liquid) tends to fall.

[0042] It is preferable that the coolant be temperature adjusted to no more than 50° C. If the coolant is temperature controlled to no more than 50° C., the temperature of the reaction product gas can be rapidly cooled in a short period of time, so the reverse reaction of the trichlorosilane generated in accordance with thermal equilibrium movement, returning to tetrachlorosilane, can be frozen.

[0043] The low-boiling point substances generated in reactor 30 such as trichlorosilane, hydrogen chloride, unreacted tetrachlorosilane, and hydrogen do not condense, even if rapidly cooled in rapid cooling tower 40, but are released from the apex part of the cooling tower 40 as uncondensed gas and supplied to condenser 60. However, while the generated hexachlorodisilane, pentachlorodisilane, and a portion of the tetrachlorosilane are condensed, mixed into the coolant, condensed with other byproducts and impurities in cooling tower 40, introduced to tank 48 connected to the bottom of rapid cooling tower 40, and circulated to spray nozzle 42 as coolant via a circulating pipeline by pump 43 connected to tank 48, a portion is extracted from the recirculation system through pipeline 45 and sent to recovery device 50 (single still 90). Pipeline 45 has a control valve or the like in the middle and the extraction speed of the condensate can be adjusted. Extraction of the coolant via pipeline 45 is performed to maintain a constant liquid composition with respect to changes in the liquid composition during circulation, but in the present invention, this is performed to adjust the amount of generated pentachlorodisilane. Accordingly, the coolant extraction speed used for this objective is preferably 5-1,000 L/h per 1,000 L/h of raw material tetrachlorosilane (prior to vaporization), more preferably, 5-500 L/h, and even more preferably, 5-100 L/h. If the extraction amount is increased, the concentration of pentachlorodisilane in the condensate falls, but as the extracted liquid amount increases, the mass of pentachloridisilane generated per unit time itself tends to increase. The mass of pentachlorodisilane generated per unit time was calculated by multiplying the specific weight of the extracted condensate of 1.5 kg/L by the extraction speed.

[0044] <Condenser>

[0045] The uncondensed gas extracted from the apex part of rapid cooling tower 40 is split in condenser 60 into a chlorosilane condensate mainly including trichlorosilane and tetrachlorosilane and uncondensed components including hydrogen and hydrogen chloride. The extracted hydrogen is reused in the raw material gas and the hydrogen chloride is separately recovered and industrially employed. The chlorosilane condensate is temporarily stored in tank 70, subsequently sent to distillation column 80, and separation into trichlorosilane and tetrachlorosilane performed. Trichlorosilane can be used as an intermediate raw material for monosilane production and tetrachlorosilane can be recycled and used again as raw material tetrachlorosilane.

[0046] <Single Still (Distillation Device, Recovery Device)>

[0047] Condensate recovery device 50 is also single still 90 and single still 90 is provided with a jacketed metal vessel 91 to warm single still 90 and a pump 92 to circulate still liquid so as not to be blocked by byproducts. In single still 90, a pipe to supply tetrachlorosilane and pentachlorodisilane vaporized in a concentration can to concentrating column 100 and a pipe supplying high-boiling point substances that do not vaporize in single still 90 to elimination equipment are connected. The unvaporized components in vaporizer 10 and the coolant in rapid cooling tower 40 are supplied to single still 90, heated at about 150° C., the tetrachlorosilane and pentachlorodisilane vaporized, supplied to concentrating column 100, and recovered. Meanwhile, the unevaporated components are extracted from single still 90 in batches or continuously and detoxified in the elimination equipment.

[0048] <Concentrating Column>

[0049] Concentrating column 100 may comprise a multi-stage distillation device having a reboiler. In concentrating column 100, vaporized gas from single still 90 is roughly separated into trichlorosilane and tetrachlorosilane and expelled from the apex of the column. Tetrachlorosilane, hexachlorodisilane, pentachlorodisilane, and other high-boiling point substances that could not be completely separated from the bottom of the column are separated. Low-boiling point substances, mainly tetrachlorosilane, are released from the apex of concentrating column 100, cooled and condensed by the cooling device, temporarily stored in tank 70, and then sent to distillation column 80. Meanwhile, high-boiling point substances, mainly hexachlorodisilane and pentachlorodisilane, are recovered from the bottom of concentrating column 100. By further vaporizing the recovered liquid in the present invention, pentachlorodisilane with increased purity can be produced.

[0050] By appropriately adjusting the temperature and pressure within concentrating column 100, the concentration of pentachlorodisilane at the bottom of the column can be sufficiently increased. As an example, it is preferable that the temperature in the column be a range from 60-200° C. and particularly preferable that it be a range from 60-150° C. Further, the pressure in the column is preferably in a range from atmospheric pressure to 0.3 MPa (absolute pressure) and particularly preferable that it be maintained in a range from atmospheric pressure to 0.2 MPa (absolute pressure).

[0051] <Distillation Column>

[0052] The liquid in tank 70 sent to distillation column 80 is separated into trichlorosilane and tetrachlorosilane. The obtained trichlorosilane can be used as an intermediate raw material for monosilane production and tetrachlorosilane can be recycled and used again as raw material tetrachlorosilane.

EXAMPLES

[0053] Below, examples of the present invention will be explained in detail. However, the specific details described in these examples do not limit the present invention.

Example 1

[0054] Sample liquid was recovered from the bottom of concentrating column 100 in equipment having the configuration indicated in the schematic drawing in FIG. 1, operated under the conditions indicated in Table 1-1 and Table 1-2 and, after a steady state was achieved in a reaction system generating trichlorosilane from tetrachlorosilane and hydrogen, with the temperature of the rapid cooling tower coolant at 50° C., the pressure in the rapid cooling tower at 0.1 MpaG, the temperature and pressure in tank 50 at 150° C. and 0.07 MpaG, and the temperature and pressure in concentrating column 100 at 100° C. and 0.1 MpaG. The supply speed of the coolant supplied to the apex of the rapid cooling tower was adjusted such that the total amount of coolant and condensate circulating in the rapid cooling tower did not change. The concentration of generated pentachlorodisilane in each liquid sample was measured using gas chromatography. The results of Example 1 are shown in Table 1-1 and Table 1-2, but it was confirmed that pentachlorodisilane was generated in the coolant condensate under all of the operating conditions. The gas chromatograph used to quantitatively measure silane compounds such as pentachlorodisilane and the measurement conditions are as follows.

[0055] Device, Recording Device: GC-14B, C-R6A (manufactured by Shimadzu Corporation)

[0056] Column: Porapak QS (Waters Corporation)

[0057] Column Size: internal diameter 3 mm ø, length 2 m

[0058] Column temperature conditions: 70° C.-220° C.

[0059] Carrier Gas: type helium, flow rate 30 mL/min.

[0060] Gas Sampler: 0.5 mL

[0061] Detector: type TCD

TABLE-US-00001 TABLE 1-1 Addition Speed of Raw Material Tetrachloro Supply Speed silane for Condensate Sample Liquid Composition Tetrachloro Hydro- addition to Extraction Reaction Trichloro Tetrachlo Pentachlorodi Hexachlorodi Octachloro silane gen Coolant speed Temperature silane rosilane silane silane trisilane Other (L/h) (Nm3/h) (L/h) (L/h) (° C.) (wt %) {circle around (1)} 1000 356 150  8 1300 0.1 7.8 14.3 66.5 5.6 5.7 {circle around (2)} 1000 356 150 15 1300 0.1 7.8 13.9 67.1 5.3 5.8 {circle around (3)} 1000 356 150 30 1300 0.1 7.8 13.2 68.2 4.9 5.8 {circle around (4)} 1000 356 150 50 1300 0.1 7.8 12.3 69.8 4.2 5.8 {circle around (5)} 1000 356 300 50 1300 0.1 7.8 11.5 70.6 5.1 5.8 {circle around (6)} 1000 356 600 50 1300 0.1 7.8  8.4 74.0 6.5 5.8

TABLE-US-00002 TABLE 1-2 Addition Speed of Raw Material Tetrachloro Supply Speed silane for Condensate Sample Liquid Composition Tetrachloro Hydro- addition to Extraction Reaction Trichloro Tetrachlo Pentachlorodi Hexachloro Octachlorodi silane gen Coolant speed Temperature silane rosilane silane silane trisilane Other (L/h) (Nm3/h) (L/h) (L/h) (° C.) (kg/h) {circle around (1)} 1000 356 150  8 1300 0.0 0.9 1.7 8.0 0.7 0.7 {circle around (2)} 1000 356 150 15 1300 0.0 1.8 3.1 15.1 1.2 1.3 {circle around (3)} 1000 356 150 30 1300 0.0 3.5 5.9 30.7 2.2 2.6 {circle around (4)} 1000 356 150 50 1300 0.1 5.9 9.2 52.4 3.2 4.4 {circle around (5)} 1000 356 300 50 1300 0.1 5.9 8.6 53.0 3.8 4.4 {circle around (6)} 1000 356 600 50 1300 0.1 5.9 6.3 55.5 4.9 4.4

Example 2

[0062] A liquid with reduced hexachlorodisilane was recovered, particularly as a raw material A from the apex of concentrating column 100, by distilling once more, using concentrating column 100, the sample liquid obtained in Example 1 under the conditions in 3 in Table 1-1 and Table 1-2 . Next, raw material A was, using distillation equipment combining two distillation columns illustrated shown schematically in FIG. 2, distilled in a 30 stage distillation column with a reflux ratio set to 8 and the temperature of the apex of the column set so as to stay at 120° C., and an intermediate raw material A was obtained from the bottom of the distillation column by removing the low-boiling portion from the apex of the column. Further, intermediate raw material A was distilled in the 30 stage distillation column with the reflux ratio set to 3 and the temperature of the apex of the column set so as to stay at 136° C., and ultimately pentachlorodisilane having a purity of at least 90 mass % was obtained from the apex of the column as a final product, substantiating the present invention. The compositions of raw material A, intermediate material A, and final purified product A in Example 2 are shown in Table 2. The concentration of the pentachlorodisilane in final purified product A was 97 mass %.

TABLE-US-00003 TABLE 2 Raw Intermediate Final Purified Component Name Material A Material A Product A Tetrachlorosilane 11% Under 0.5% Under 0.5% Tetrachlorodisilane 10% Under 0.5% Under 0.5% Hexachlorodisiloxane  4%  3%  3% Pentachlrodisilane 60% 80% 97% Hexachlorodisilane 15% 17% Under 0.5% (percentages are mass percentages)

Example 3

[0063] The sample liquid obtained in Example 1 under the conditions in 3 in Table 1-1 and Table 1-2 was recovered particularly as a raw material B from the bottom of concentrating column 100. Next, raw material B was, using distillation equipment combining two distillation columns illustrated shown schematically in FIG. 2, first distilled in a 50 stage distillation column with the reflux ratio set to 10 and the temperature of the apex of the column set so as to stay at 120° C., obtaining an intermediate raw material B-1 from the bottom of the column by removing the low-boiling portion from the apex of the column. Furthermore, a raw material B-2 was obtained from the top of the same distillation column, that is, a 50 stage distillation column with the reflux ratio set to 5 and set such that the temperature of the top of the column stays at 135° C. Further, in the second 70 stage distillation column, the reflux ratio was set to 50 and the temperature of the apex of the column was set so as to stay at 136° C., pentachlorodisilane having purity of at least 90 mass % was ultimately obtained as the final product from the bottom of the column, substantiating the present invention. The compositions of raw material B, intermediate raw material B-1, intermediate raw material B-2 and final purified product B in Example 3 are shown in Table 3. The concentration of the pentachlorodisilane in final purified product B was 99.5 mass %.

TABLE-US-00004 TABLE 3 Final Raw Intermediate Intermediate Purified Component Name Material B Material B-1 Material B-2 Product B Tetrachlorosilane 10% Under 0.5% Under 0.5% Under 0.5% Other 10%  2% Under 0.5% Under 0.5% Hexachloro-  5%  4%  4%  0.5% disiloxane Pentachlrodisilane 15% 30% 96% 99.5% Hexachloro- 60% 64% Under 0.5% Under 0.5% disilane (percentages are mass percentages)

EXPLANATION OF THE REFERENCE NUMBERS

[0064] 10 Vaporizer

[0065] 20 Preheater

[0066] 30 Reactor

[0067] 31 Reactor vessel

[0068] 32 Heater

[0069] 33 External cylindrical vessel

[0070] 34 Extraction pipe

[0071] 40 Rapid cooling tower

[0072] 41 Metal vessel

[0073] 42 Spray nozzle

[0074] 43 Pump

[0075] 44 Cooling device

[0076] 45 Pipeline (adjustment means)

[0077] 46 Packing layer

[0078] 47 Pipe

[0079] 48 Tank

[0080] 49 Inlet pipe (adjustment means)

[0081] 50 Recovery device

[0082] 60 Condenser

[0083] 70 Tank

[0084] 80 Distillation column

[0085] 90 Single still (distillation device)

[0086] 91 Jacketed metal vessel

[0087] 92 Pump

[0088] 100 Concentrating column