JP5321314B2 - Method and apparatus for decomposing chlorosilane polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently decompose a chlorosilane polymer without corroding the outer wall of a reaction furnace. <P>SOLUTION: A method for decomposing the chlorosilane polymer includes a preheating step to preheat a raw material gas made by mixing the chlorosilane polymer with HCl to a preheating temperature Ti(&deg;C) and a decomposing step to leave the preheated raw material gas in a decomposing furnace. When the average retention time in the decomposing furnace of the raw material gas in the decomposing step is expressed as t (sec), such equations as T1&le;Ti&le;T2, T1=600&times;t<SP>(-0.057)</SP>-150 and T2=190&times;t<SP>(-0.9)</SP>+470 (wherein, t&le;10; and 400&le;Ti&le;550) are satisfied. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a method for decomposing a chlorosilane polymer for converting a chlorosilane polymer generated during the production of polycrystalline silicon into a monomer such as trichlorosilane (SiHCl ₃ (TCS)) or silicon tetrachloride (SiCl ₄ (STC)). And a decomposition apparatus.

  High-purity polycrystalline silicon used for semiconductor materials is, for example, a method in which trichlorosilane and hydrogen are used as raw materials, and this mixed gas is introduced into a reduction furnace to deposit silicon on the surface of a silicon rod installed in the reduction furnace. (Siemens method). The high-purity trichlorosilane introduced into the reduction furnace may be, for example, introducing metal silicon and hydrogen chloride into the chlorination furnace and reacting them to chlorinate silicon or introducing silicon tetrachloride and hydrogen into the conversion furnace. It is manufactured by reacting.

In the production of these polycrystalline silicon and trichlorosilane, pentachlorodisilane (Si ₂ HCl ₅ ), as well as useful trichlorosilane, silicon tetrachloride, hydrogen and hydrogen chloride are used as the exhaust gas of the reduction furnace, chlorination furnace, and conversion furnace. High-boiling chlorosilane polymers (polymers) containing two or more silicon atoms, such as hexachlorodisilane (Si ₂ Cl ₆ ) and octachlorotrisilane (Si ₃ Cl ₈ ), are included.

  Conventionally, polymers separated from the exhaust gas of a reduction furnace, a chlorination furnace, or a conversion furnace have been subjected to hydrolysis treatment to be converted to silica and discarded.

  On the other hand, for the purpose of converting the polymer into useful trichlorosilane or silicon tetrachloride, the polymer is brought into contact with a catalyst such as activated carbon, alumina, platinum, palladium in the presence of hydrogen chloride and hydrogen. A method of decomposing a polymer by performing catalytic conversion to a chlorosilane monomer is known (Patent Document 1).

Japanese Patent Application Laid-Open No. 07-101713

  However, the reaction in which the polymer is decomposed in the presence of hydrogen chloride and hydrogen is an exothermic reaction, and the reaction temperature increases as the polymer decomposition proceeds. In particular, in the reaction using a catalyst, heat generation may occur rapidly due to a high reaction rate, so that the reaction temperature rises rapidly, the catalyst deteriorates at a high temperature and deactivates, or the temperature of the cracking furnace filled with the catalyst. There was a problem such as the value rose above the design value. In particular, the temperature rise in the cracking furnace may lead to corrosion of the wall material by hydrogen chloride as a raw material. Therefore, in order to suppress the increase in reaction temperature, it is necessary to dilute and react the polymer by supplying excess hydrogen or hydrogen chloride, which is uneconomical in terms of efficiency, such as a large cracking furnace. It was.

  The present invention has been made in view of such circumstances, and by sufficiently controlling the reaction temperature, the wall temperature of the decomposition apparatus is suppressed to a design value or less, and the chlorosilane polymer can be obtained without corroding the wall of the decomposition furnace. The purpose is to decompose efficiently.

The present invention includes a preheating step of preheating a raw material gas formed by mixing a chlorosilane polymer and HCl to a preheating temperature Ti [° C.]
A decomposition step of retaining the preheated raw material gas in a decomposition furnace,
When the average residence time t [second] in the decomposition furnace of the source gas in the decomposition step is set, the preheating temperature Ti is set to 400 ≦ Ti ≦ 550.
And T1 ≦ Ti ≦ T2
T1 = 600 × t ^(−0.057) −150
T2 = 190 × t ^(−0.9) +470
Where t ≦ 10
This is a decomposition method of a chlorosilane polymer set so as to satisfy the above.

By preheating the raw material gas introduced into the cracking furnace to 400 ° C. or more and 550 ° C. or less at which the polymer decomposition reaction starts, the decomposition reaction of the raw material gas proceeds in the decomposition furnace, and the temperature of the raw material gas is reduced by the heat of the decomposition reaction It further rises and the decomposition reaction further proceeds. Further, if the preheating temperature is 400 ° C. or more and 550 ° C. or less, corrosion or stress corrosion cracking due to HCl can be prevented even if a metal part such as stainless steel is used for the preheater used in the preheating process. However, when the average residence time t in the cracking furnace is short, the preheating temperature of the raw material gas is too low at 400 ° C. and the decomposition rate of the polymer decreases, so T1 (≧ 400 ° C.) determined from the average residence time t is Set to the lower limit of the preheating temperature. On the other hand, when the average residence time t is long, the preheating temperature of the raw material gas is too high at 550 ° C., and the decomposition rate of the polymer becomes high. On the other hand, the reaction temperature rises too much and the yield of SiHCl ₃ decreases. Since the metal parts of the preheater are likely to be corroded, T2 (≦ 550 ° C.) obtained from the average residence time t is set as the upper limit of the preheat temperature.

  Therefore, according to this decomposition method, an appropriate preheating temperature can be set according to the average residence time t, the decomposition reaction in the decomposition furnace can be performed efficiently, and an excessive temperature rise in the decomposition furnace is suppressed, Corrosion and stress corrosion cracking of metal parts such as preheaters and piping can be prevented.

In this decomposition method, the preheating temperature Ti is further set to Ti ≦ Tb2
Tb2 = 190 × t ^(−0.59) +400
It is preferable to satisfy. In this case, by suppressing the upper limit of the preheating temperature to Tb2 lower than T2, it is possible to more reliably suppress an increase in reaction temperature and more reliably prevent a decrease in yield of SiHCl ₃ .

The present invention also provides a cracking furnace supplied with a raw material gas obtained by mixing a chlorosilane polymer and HCl, a heat insulating layer provided so as to cover an inner wall of the cracking furnace, and the raw material gas at a predetermined preheating temperature Ti. A raw material gas supply section that is heated to [° C.] and is supplied to the cracking furnace, and a control section that controls the preheating temperature Ti according to an average residence time t [second] of the raw material gas in the cracking furnace A chlorosilane polymer decomposition apparatus comprising the control unit, wherein the preheating temperature Ti [° C.] is set to 400 ≦ Ti ≦ 550.
And T1 ≦ Ti ≦ T2
T1 = 600 × t ^(−0.057) −150
T2 = 190 × t ^(−0.9) +470
Where t ≦ 10
Control to meet.

  According to this decomposition apparatus, a raw material gas having an appropriately controlled preheating temperature is put into a decomposition furnace having a heat insulating layer on the inside. Since the thermal decomposition layer is provided in the decomposition furnace, the reaction temperature of the raw material gas is maintained by the heat of decomposition reaction of the polymer, and the temperature increase of the decomposition furnace is suppressed. That is, by providing the heat insulating layer, the cracking furnace can be maintained at a relatively low temperature even when the reaction temperature increases. Therefore, a sufficient polymer decomposition rate can be obtained while suppressing corrosion of metal parts such as a decomposition furnace.

In this decomposition apparatus, the preheating temperature Ti is further set to Ti ≦ Tb2
Tb2 = 190 × t ^(−0.59) +400
It is preferable to satisfy. In this case, the preheating temperature of the source gas can be set in a more appropriate range.

  In this decomposition apparatus, the decomposition furnace includes an inner container provided inside the heat insulating layer and an outer container provided outside the heat insulating layer, and the space between the inner container and the outer container is inactive. It is preferably purged with gas. In this case, even if gas leaks from the inner container, it is possible to prevent the gas from staying inside the outer container, avoiding contact between the outer container and HCl, and effectively preventing corrosion of the outer container.

  In this decomposition apparatus, it is preferable that a heater is provided inside the heat insulating layer. In this case, the heat loss due to the heat insulation layer is supplemented by a heater, polymer decomposition reaction at a high temperature is possible, and the heat insulation layer suppresses the temperature rise of the cracking furnace while preventing direct gas contact with the cracking furnace. it can.

  In this decomposition apparatus, the source gas supply unit includes an HCl preheater that heats the HCl, and a polymer evaporator that evaporates the chlorosilane polymer while being supplied with HCl heated by the HCl preheater. preferable. In this case, it is possible to prevent the heated polymer from being thermally decomposed to produce solid silicon by high-temperature HCl.

  According to the method and apparatus for decomposing chlorosilane polymer of the present invention, the reaction temperature can be adjusted to an appropriate range, and the polymer can be efficiently produced while preventing the corrosion by suppressing the temperature rise of metal parts such as preheaters and decomposition furnaces. Can be disassembled.

It is a schematic diagram which shows the decomposition | disassembly apparatus of the chlorosilane polymer based on this invention. It is a figure which shows the relationship between the reaction time of the raw material gas in the decomposition reaction of a chlorosilane polymer, gas temperature (a), polymer amount (b), and TCS amount (c) about each preheating temperature. It is a figure which shows the relationship between the preheating temperature of raw material gas and reaction time in the decomposition reaction of a chlorosilane polymer. It is a schematic diagram which shows 2nd Embodiment of the decomposition | disassembly apparatus of the chlorosilane polymer based on this invention. It is a schematic diagram which shows 3rd Embodiment of the decomposition | disassembly apparatus of the chlorosilane polymer based on this invention. It is a schematic diagram which shows 4th Embodiment of the decomposition | disassembly apparatus of the chlorosilane polymer based on this invention. It is a schematic diagram which shows 5th Embodiment of the decomposition | disassembly apparatus of the chlorosilane polymer based on this invention.

Hereinafter, embodiments of a decomposition method and a decomposition apparatus for a chlorosilane polymer (polymer) according to the present invention will be described.
The polymer is a polymer of chlorosilane represented by Si _n H _a Cl _b (n ≧ 2, 0 ≦ a ≦ 2n + 2, b = 2n + 2-a) such as Si ₂ Cl ₆ and Si ₃ Cl ₈ . It is decomposed as follows.
_{Si n H a Cl b + cHCl} → dSiHCl 3 + eSiCl 4 + fH 2 ... (1)
Furthermore, SiHCl ₃ changes to SiCl ₄ by reaction with HCl.
SiHCl ₃ + HCl → SiCl ₄ + H ₂ (2)
When the chlorosilane polymer is decomposed, it is required to efficiently generate TCS (SiHCl ₃ ).

  The decomposition apparatus 10 of the present invention includes a decomposition furnace 20 to which a raw material gas G1 formed by mixing a chlorosilane polymer (polymer) and HCl is supplied, a heat insulating layer 30 provided so as to cover the inner wall of the decomposition furnace 20, The source gas G1 is heated to a predetermined preheating temperature Ti [° C.] and supplied to the cracking furnace 20, and the preheating is performed according to the average residence time t [second] of the source gas G1 in the cracking furnace 20. And a control unit 50 for controlling the temperature Ti.

  The cracking furnace 20 is a substantially cylindrical stainless steel container having a diameter of 40 cm with the upper and lower ends closed, and includes a reaction chamber 21 formed inside the heat insulating layer 30. The heat insulation layer 30 is made of 15 cm thick carbon felt that does not easily react with HCl, covers the inner wall of the cracking furnace 20, and forms a substantially cylindrical reaction chamber 21 having a diameter of about 10 cm. A source gas G1 supply pipe 22 is opened at the lower end of the reaction chamber 21, and a product gas G2 discharge pipe 23 is opened at the upper end. The reaction chamber 21 is provided with a baffle plate 24 made of a corrosion-resistant material such as carbon and forming a flow path for the source gas G1. Therefore, the source gas G1 supplied from the source gas supply unit 40 to the lower part of the reaction chamber 21 through the supply pipe 22 proceeds in the reaction chamber 21 while meandering by the baffle plate 24, and from the upper part of the reaction chamber 21 through the discharge pipe 23. It is discharged as product gas G2.

  The raw material gas supply unit 40 supplies the raw material gas G1 obtained by heating and mixing the polymer and HCl to the cracking furnace 20 at an arbitrary temperature and an arbitrary supply amount. In the source gas supply unit 40, the temperature and supply amount of the polymer and HCl are controlled by the control unit 50.

  In the raw material gas supply unit 40, first, the polymer supply unit 41 supplies the liquid polymer to the polymer evaporator 42. The supply amount of the liquid polymer is controlled by the control unit 50. On the other hand, the HCl supply unit 44 supplies HCl to the HCl preheater 45. The supply amount of HCl is controlled by the control unit 50. The HCl preheater 45 supplied with HCl is controlled by the control unit 50 to heat HCl to an arbitrary temperature (120 ° C. or more and 300 ° C. or less), and supplies it to the polymer evaporator 42.

  The polymer evaporator 42 heats and evaporates the liquid polymer. At this time, the high-temperature HCl is supplied to the polymer evaporator 42, thereby preventing the heated polymer from being thermally decomposed and generating solid silicon. The polymer evaporated in the polymer evaporator 42 is mixed with HCl and sent to the raw material gas preheater 43.

  The raw material gas preheater 43 further heats the polymer mixed with the polymer evaporator 42 and HCl, and sends the raw material gas G1 having an arbitrary preheating temperature Ti to the cracking furnace 20. The preheating temperature Ti is controlled by the control unit 50 in accordance with the average residence time t of the raw material gas G1 in the cracking furnace 20.

Here, the preheating temperature Ti [° C.] is set to 400 ≦ Ti ≦ 550 by the control unit 50.
And T1 ≦ Ti ≦ T2
T1 = 600 × t ^(−0.057) −150
T2 = 190 × t ^(−0.9) +470
Where t ≦ 10
It is controlled to satisfy. T1 is a lower limit temperature of the preheating temperature Ti, and T2 is an upper limit temperature.

The average residence time t [seconds] is calculated as follows, and is controlled by the control unit 50 controlling the raw material supply amount.
Average residence time t = V ÷ F (3)
V: volume of reaction chamber 21 [m ³ ]
F: Flow rate [m ³ / sec]
Flow rate F = N × R × Ti ÷ P (4)
N: Raw material supply amount [mol / sec]
R: Gas constant (8.314 [J / mol / K])
Ti: Preheating temperature [K] of the raw material gas G (that is, the inlet gas temperature of the cracking furnace 20)
P: Pressure [Pa (A)] (absolute pressure standard)

  That is, in the cracking apparatus 10, the control unit 50 controls the average residence time t by controlling the preheating temperature Ti of the raw material gas G1 introduced into the cracking furnace 20 and controlling the supply amount of the raw material gas G1.

  Since the raw material gas G1 supplied to the cracking furnace 20 is preheated to 400 ° C. or more and 550 ° C. or less at which the decomposition reaction starts, it starts to be decomposed in the reaction chamber 21 as in the above formula (1). Since this decomposition reaction is an exothermic reaction and the reaction chamber 21 is covered with the heat insulating layer 30, the temperature of the source gas G1 further rises and the decomposition reaction further proceeds. The product gas G2 after the reaction is discharged from the cracking furnace 20 through the exhaust pipe 23, and is quickly cooled to finish the decomposition reaction. TCS is recovered from the product gas G2.

  In this decomposition reaction, since the heat insulating layer 30 covering the inner wall of the decomposition furnace 20 is provided, heat dissipation from the reaction chamber 21 is hindered. Therefore, since the temperature of the source gas G1 can be increased using the reaction heat, a sufficient decomposition reaction can be caused in the reaction chamber 21 even if the preheating temperature Ti of the source gas G1 is kept relatively low. it can. For this reason, since the temperature rise of the metal parts contacting the source gas G1 or the generated gas G2 such as the cracking furnace 20, the polymer evaporator 42, the source gas preheater 43, the supply pipe 22 and the discharge pipe 23 is suppressed, corrosion by HCl Can be suppressed.

Here, the relationship between the preheating temperature Ti of the raw material gas G1, the decomposition reaction time, the gas temperature, the amount of polymer (Si ₂ Cl ₆ ), and the amount of TCS will be described with reference to FIG. FIG. 2 shows the changes in gas temperature (a), polymer amount (b), and TCS amount (c) due to the decomposition reaction when the temperature of the raw material gas G1 is 380 ° C., 480 ° C., and 540 ° C. Assuming that the layer 30 is completely insulated, the simulation results are shown in the graph.

  When the preheating temperature Ti is 540 ° C., the polymer is decomposed and becomes almost zero within about 0.1 second from the start of the reaction, but once the TCS produced is reacted with HCl in the gas and decreased. End up. The polymer decomposition and the TCS reaction are both exothermic reactions, which raise the gas temperature to about 900 ° C. and reach a steady state. Therefore, when the preheating temperature Ti is 540 ° C., the TCS is efficiently obtained by terminating the reaction after the source gas G1 is retained in the cracking furnace 20 for about 0.1 seconds to 0.2 seconds. Can be produced.

  When the preheating temperature Ti is 480 ° C., about 1 second from the start of the reaction, the polymer is decomposed to become almost zero, and at the same time, the amount of TCS becomes maximum. Thereafter, the TCS decreases due to the exotherm of these reactions. Therefore, when the preheating temperature Ti is 480 ° C., TCS can be efficiently produced by terminating the reaction after the source gas G1 is retained in the cracking furnace 20 for about 1 second.

  When the preheating temperature Ti is 380 ° C., the gas temperature hardly changes, and the amount of polymer and TCS does not change so much. That is, when the preheating temperature Ti is low, the polymer decomposition reaction is not performed.

  From these, it can be seen that TCS can be efficiently produced by appropriately setting the relationship between the preheating temperature Ti and the duration of the reaction, that is, the residence time in the cracking furnace 20.

<Examples and Comparative Examples>
Using the decomposition apparatus 10 described above, the preheating temperature Ti and the average residence time t (that is, the amount of polymer supplied) were adjusted, and the polymer decomposition treatment was performed. Conditions common to each example and comparative example are shown below.
Volume of reaction chamber 21: 5.0 [L]
Heat insulation layer 30 thickness: 0.15 m
Pressure: 0.05 [MPa (G)] (atmospheric pressure standard)
The composition (molar ratio) of the raw material gas G1 introduced into the cracking furnace 20 is as shown in Table 1.

  Table 2 and FIG. 3 show the results of measuring the polymer decomposition rate, the TCS production rate, the temperature of the product gas G2, and the temperature of the decomposition furnace 20 for each example and comparative example. In this test result, the higher the polymer degradation rate and the TCS production rate, the better. Moreover, in order to suppress corrosion of metal parts, it is preferable that the gas temperature is low and the temperature of the decomposition furnace 20 is low. Here, if the polymer degradation rate was 90% or more and the TCS production rate was positive, it was determined as OK.

The polymer degradation rate is calculated as in the following formula, and becomes negative when the amount of polymer is increased from the raw material.
Polymer degradation rate [%] = 100-polymer amount after reaction [mol] / polymer amount in raw material [mol] × 100 (5)
Here, the decomposition rate was measured for Si ₂ HCl ₅ and Si ₂ Cl ₆ occupying 90% or more of the entire polymer.

The TCS production rate is calculated by the following equation, and becomes negative when the TCS is reduced from the raw material gas G1.
TCS production rate [%] = 100 × (TCS amount [mol] in product gas G2−TCS amount [mol] in source gas G1) / (Amount of silicon contained in TCS and polymer in source gas G1 [mol]) (6)

<When preheating temperature Ti is 545 ° C.>
In Example 1 indicated by point a in FIG. 3 and Example 2 indicated by point b, the preheating temperature Ti of the source gas G1 is set to 545 ° C. In these cases, although the preheating temperature Ti was relatively high and the TCS production rate of Example 1 having a short average residence time t was higher, the polymer degradation rate was 90% or more in all cases.
On the other hand, in Comparative Example 1 indicated by a point k in FIG. 3, the average residence time t is set to 3.4 seconds, which is longer than those of Examples 1 and 2 where the preheating temperature Ti is the same. From T2 in this average residence time t However, the preheating temperature Ti is high. In this case, the polymer degradation rate was as high as 100%, but the TCS production rate was low. This is because the reaction time was too long for the gas temperature, in other words, the gas temperature was too high for the reaction time, and the generated TCS was changed to SiCl ₄ by the reaction shown in the above formula (2). it is conceivable that.

<When preheating temperature Ti is 480 ° C.>
In Example 3 indicated by point c in FIG. 3, Example 4 indicated by point d, and Example 5 indicated by point e, the preheating temperature Ti of the source gas G1 is set to 480 ° C. In these cases, both the polymer degradation rate and the TCS production rate were high.
On the other hand, in Comparative Example 2 indicated by a point l in FIG. 3, the average residence time t was set shorter than in Examples 3 to 5 having the same preheating temperature Ti, and the polymer decomposition rate was low. This is probably because the reaction time was short with respect to the gas temperature, and the polymer was not sufficiently decomposed.
Further, in Comparative Example 3 indicated by a point m in FIG. 3, the average residence time t is set to 11 seconds, which is longer than that of Examples 3 to 5 where the preheating temperature Ti is the same, and the TCS production rate is high although the polymer decomposition rate is high. Was low. This is presumably because the reaction time was too long for the gas temperature, and the generated TCS was changed to SiCl ₄ by the reaction shown in the above formula (2).

<When preheating temperature Ti is 450 ° C.>
In Example 6 indicated by a point f in FIG. 3, Example 7 indicated by a point g, and Example 8 indicated by a point h, the preheating temperature Ti of the source gas G1 is set to 450 ° C. In these cases, both the polymer degradation rate and the TCS production rate were high.

<When preheating temperature Ti is 405 ° C.>
In Example 9 indicated by point i in FIG. 3 and Example 10 indicated by point j, the preheating temperature Ti of the source gas G1 is set to 405 ° C. In these cases, although the preheating temperature Ti is relatively low and the average residence time t is short in Example 9, the polymer decomposition rate was slightly low, but a high TCS production rate was obtained, while the average residence time t was long. In Example 10, the polymer degradation rate was 100%, but the TCS production rate was lower than Example 9.
On the other hand, in Comparative Example 4 indicated by a point n in FIG. 3, the average residence time t is set to 2.2 seconds, which is shorter than those of Examples 9 and 10 having the same preheating temperature Ti, and is longer than T1 at this average residence time t. The preheating temperature Ti is low. In Comparative Example 4, the polymer degradation rate was low because the reaction time was short with respect to the gas temperature, in other words, the gas temperature was low with respect to the reaction time, and thus the polymer was not sufficiently decomposed. It is done.
Further, in Comparative Example 5 indicated by a point o in FIG. 3, the average residence time t is set to 11 seconds, which is longer than that of Examples 9 and 10 where the thermal temperature Ti is the same, and the TCS production rate is high although the polymer decomposition rate is high. Was low. This is presumably because the reaction time was too long for the gas temperature, and the generated TCS was changed to SiCl ₄ by the reaction shown in the above formula (2).

<When preheating temperature Ti is too low>
Further, in Comparative Example 6 indicated by a point p in FIG. 3, the preheating temperature Ti of the source gas G1 is set to 380 ° C., and the average residence time t is set to 11 seconds. In this case, both the polymer degradation rate and the TCS production rate were low. In view of the fact that the temperature of the product gas G2 is not so high as compared with the preheating temperature Ti, in this Comparative Example 6, the preheating temperature Ti is too low, so the polymer decomposition reaction is not started, and the average residence time t It is considered that sufficient decomposition reaction was not performed even if the length was long. From this, it was confirmed that the preheating temperature Ti is preferably set to 400 ° C. or higher.

<When average residence time t is too long>
In Comparative Examples 3, 5 and 6, the average residence time t is set to 11 seconds. Among these comparative examples, in Comparative Example 6 (point p in FIG. 3) where the preheating temperature Ti is low, the decomposition reaction is insufficient, and Comparative Examples 3 and 5 (points m and o in FIG. 3) where the preheating temperature Ti is high. Then, the reverse reaction of TCS generation (formula (2)) proceeds. Therefore, it was confirmed that the average residence time t is preferably set within 10 seconds regardless of the preheating temperature Ti.

<Effects of heat insulating layer 30>
In these Examples 1-10 and Comparative Examples 1-6, since the heat insulation layer 30 was provided, the temperature of the decomposition furnace 20 was suppressed to 500 degrees C or less. Thereby, in the decomposition apparatus 10 of this invention, it was confirmed that the decomposition | disassembly reaction of a polymer can advance, suppressing corrosion of metal components, such as the decomposition furnace 20, by high temperature hydrogen.

  As explained above, according to the decomposition method according to the present invention, the decomposition apparatus 10 according to the present invention is used to suppress corrosion of metal parts such as the decomposition furnace 20 and to suppress excessive reaction, and to make the chlorosilane polymer efficient. It can be decomposed well and enables highly efficient polymer decomposition. In other words, in the cracking furnace 20 having a certain volume, the preheating temperature Ti has only to be set appropriately in accordance with the polymer supply amount, so that the polymer processing amount can be changed. Furthermore, since the reaction temperature can be controlled stably, stable operation becomes possible.

In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, it is possible to add a various change in the range which does not deviate from the meaning of this invention.
For example, the preheating temperature Ti of the raw material gas G1 is further Ti ≦ Tb2
Tb2 = 190 × t ^(−0.59) +400
It is more preferable to set so as to satisfy. In this case, by setting the upper limit temperature of the preheating temperature Ti to Tb2 lower than T2, the maximum temperature of the gas in the reaction chamber 21 due to the reaction heat can be suppressed, so that it is more effective that TCS is converted to SiCl _4. And corrosion of the cracking furnace 20 can be more reliably suppressed.

  Moreover, various configurations can be adopted for the decomposition furnace 20 of the decomposition apparatus 10 as follows. In addition, about the raw material gas supply part 40 in the following decomposition | disassembly apparatuses 10, what is the structure similar to the raw material gas supply part 40 with which the decomposition | disassembly apparatus 10 of 1st Embodiment mentioned above is equipped is abbreviate | omitted illustration and description here. .

  FIG. 4 shows a second embodiment of the disassembling apparatus 10. The decomposition furnace 20 </ b> A in this embodiment is provided with a heater 31 inside the heat insulating layer 30. The heater 31 is a carbon heater, a ceramic heater or the like that is not corroded by HCl. In this cracking furnace 20A, when the heat release effect from the cracking furnace 20A is large and the temperature rise of the raw material gas G1 due to the reaction heat is insufficient, such as the heat insulation effect by the heat insulation layer 30 is not sufficiently obtained, the reaction chamber 21 The gas inside can be supplementarily heated. In addition, by raising at least a part of the gas in the reaction chamber 21 to a high temperature, the reaction can be accelerated and a more stable polymer decomposition rate can be obtained.

  FIG. 5 shows a third embodiment of the disassembling apparatus 10. The decomposition furnace 20 </ b> B in this embodiment includes an inner container 25 that is provided inside the heat insulating layer 30 to form the reaction chamber 21, and an outer container 26 that is provided outside the heat insulating layer 30. The inner container 25 is a carbon container that is not corroded by HCl, and the decomposition reaction is performed inside the inner container 25. The supply pipe 22 for the source gas G1 and the discharge pipe 23 for the product gas G2 are open to the inner container 25. The outer container 26 covering the inner container 25 and the heat insulating layer 30 is a stainless steel container having excellent hermeticity, and the inside is purged by supplying a purge gas.

The purge gas is composed of at least one kind of inert gas such as H ₂ , N ₂ , Ar gas, etc., and is supplied to the inside of the outer container 26 through the purge gas supply pipe 27. And the gas discharged | emitted from the outer container 26 is derived | led-out to the discharge pipe 23 of the production gas G2 through the purge gas discharge pipe 28, and is mixed in the production gas G2. Thus, in this cracking furnace 20B, the internal gas in the outer container 26 is purged, so that the raw material gas G1 leaking from the inner container 25 is prevented from staying in the outer container 26, and the outer container 26 and HCl are separated. Contact with can be avoided. Thereby, corrosion of the stainless steel outer container 26 by HCl of the source gas G1 is effectively prevented. That is, in this embodiment, while having corrosion resistance to HCl, the inner container 25 made of carbon having low sealing properties is covered with the outer container 26 made of stainless steel having high sealing properties, while having low corrosion resistance to HCl. By interposing the heat insulating layer 30 between the outer container 26 and the outer container 26, both the decomposition reaction of the polymer at a high temperature and the corrosion prevention of the stainless steel container are achieved.

  FIG. 6 shows a fourth embodiment of the disassembling apparatus 10. The decomposition furnace 20C in this embodiment includes a heater 31 outside the inner container 25 forming the reaction chamber 21, and has a structure in which the inner container 25, the heater 31, and the heat insulating layer 30 are accommodated in the outer container 26. . Thereby, in this decomposition furnace 20C, the heat loss due to the heat insulating layer 30 in the reaction chamber 21 is supplemented by the heater 31 to enable the polymer decomposition reaction at a high temperature, and the raw material gas G1 is directly supplied to the outer container 26 made of stainless steel. While preventing contact, the heat insulating layer 30 suppresses the temperature rise of the outer container 26.

  FIG. 7 shows a fifth embodiment of the disassembling apparatus 10. In the raw material gas supply unit 40A in this embodiment, a heat exchanger 47 for the product gas G2 and the raw material HCl is provided in the middle of an HCl supply line 46 for supplying the raw material HCl from the HCl supply unit 44 to the polymer evaporator 42. Yes. The raw material HCl supplied to the polymer evaporator 42 is heated by the heat exchanger 47 and the product gas G2 discharged from the cracking furnace 20 is cooled, so that the efficiency of utilizing the reaction heat of polymer decomposition is high. Processing is possible.

DESCRIPTION OF SYMBOLS 10 Decomposition | disassembly apparatus 20,20A, 20B, 20C Decomposition furnace 21 Reaction chamber 22 Supply pipe 23 Discharge pipe 24 Baffle plate 25 Inner container 26 Outer container 27 Purge gas supply pipe 28 Purge gas discharge pipe 30 Heat insulation layer 40 Raw material gas supply part 41 Polymer supply part 42 Polymer Evaporator 43 Source Gas Preheater 44 HCl Supply Unit 45 HCl Preheater 46 HCl Supply Line 47 Heat Exchanger 50 Control Unit 50
G1 Source gas G2 Product gas Ti Preheating temperature T1 Lower limit temperature T2 Upper limit temperature t Average residence time

Claims (7)

A preheating step of preheating a raw material gas obtained by mixing a chlorosilane polymer and HCl to a preheating temperature Ti [° C.];
A decomposition step of retaining the preheated raw material gas in a decomposition furnace,
When the average residence time t [second] in the decomposition furnace of the source gas in the decomposition step is set, the preheating temperature Ti is set to 400 ≦ Ti ≦ 550.
And T1 ≦ Ti ≦ T2
T1 = 600 × t ^(−0.057) −150
T2 = 190 × t ^(−0.9) +470
Where t ≦ 10
A method for decomposing a chlorosilane polymer, wherein the chlorosilane polymer is set so as to satisfy The preheating temperature Ti is further equal to Ti ≦ Tb2.
Tb2 = 190 × t ^(−0.59) +400
The method for decomposing a chlorosilane polymer according to claim 1, wherein: A cracking furnace supplied with a raw material gas formed by mixing a chlorosilane polymer and HCl;
A heat insulating layer provided to cover the inner wall of the cracking furnace;
A source gas supply unit for heating the source gas to a predetermined preheating temperature Ti [° C.] and supplying the source gas to the cracking furnace;
A chlorosilane polymer decomposition apparatus comprising a control unit that controls the preheating temperature Ti according to an average residence time t [second] of the source gas in the decomposition furnace,
The control unit sets the preheating temperature Ti to 400 ≦ Ti ≦ 550.
And T1 ≦ Ti ≦ T2
T1 = 600 × t ^(−0.057) −150
T2 = 190 × t ^(−0.9) +470
Where t ≦ 10
An apparatus for decomposing a chlorosilane polymer, wherein the apparatus is controlled to satisfy the above. The preheating temperature Ti is further equal to Ti ≦ Tb2.
Tb2 = 190 × t ^(−0.59) +400
The apparatus for decomposing a chlorosilane polymer according to claim 3, wherein:   The cracking furnace includes an inner container provided inside the heat insulating layer and an outer container provided outside the heat insulating layer, and the space between the inner container and the outer container is purged with an inert gas. The apparatus for decomposing a chlorosilane polymer according to claim 3 or 4, wherein:   The chlorosilane polymer decomposition apparatus according to any one of claims 3 to 5, wherein a heater is provided inside the heat insulating layer.   The raw material gas supply unit includes an HCl preheater that heats the HCl, and a polymer evaporator that evaporates the chlorosilane polymer while being supplied with HCl heated by the HCl preheater. The apparatus for decomposing a chlorosilane polymer according to any one of 3 to 6.

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