Patent Publication Number: US-2012039760-A1

Title: Hermetic Container for Thermal Conversion Reaction

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present invention relates to a hermetic container for thermal conversion reaction, and more particularly to a hermetic container for thermal conversion reaction, in which reaction gas is supplied to an inside of a hot zone as it is heated by absorbing thermal energy escaping outward via a vessel, thereby preventing the vessel from being heated at a limit temperature or over, and reducing power consumption of a heater for maintaining an inner temperature of the hot zone. 
     (b) Description of the Related Art 
     Hitherto, solar grade silicon has been generally acquired from a surplus material of a semiconductor industry. However, some manufacturers of semiconductor grade silicon commercially produce a solar grade material through typical processes. One of the typical processes converts metallurgical silicon into one of silane, polysilane and chlorosilane compounds. Silane, polysilane or chlrorosilane is pyrolyzed in a Siemens-type reactor and forms highgrade purity polysilicon. 
     In such a Siemens-type process, a polysilicon rod is manufactured by pyrolysis of a gaseous silicon compound, e.g., silane, polysilane or chloro silane on a filament substrate so-called a slim rod. The slim rod is generally manufactured with highgrade purity polysilicon in order to secure a level of product purity. 
     As above, while producing polycrystalline silicon by reacting trichlorosilane (SiHCl 3 , hereinafter referred to as ‘TCS’) with hydrogen in a reactor, plenty of silicon tetrachloride (SiCl 4 , hereinafter referred to as ‘STC’) is acquired during participation of polycrystalline silicon. 
     STC mixed with hydrogen (H 2 ) is reduced by thermal hydrogenation into TCS and then reused. 
       FIG. 1  is a cross-sectional view of a conventional converter that converts STC into TCS through thermal conversion. As shown therein, in the conventional converter, a heater  13  is arranged on a top of a base plate  10 , and a bell-curve or bell-jar type vessel  20  for forming a hot zone  21  is assembled to an upper side of the base plate  10 . Further, a shield  40  is installed between the heater  13  and the vessel  20  so as to prevent internal heat of the hot zone  21  from being transferred to the vessel  20  and escaping outward. 
     In such an assembled state, if the heater  13  is powered on and heats the hot zone  21  to have an inner temperature of about 900° C. to 1500° C. while supplying mixed gas of STC and H 2  (hereinafter, referred to as ‘reaction gas’) to the hot zone  21  through an inlet hole  11  formed on the base plate  10 , the reaction gas within the hot zone  21  is converted into TCS and hydrogen chloride (HCl) by hydrogenation at high temperature and discharged through an outlet hole  12 . 
     The vessel  20  surrounding the hot zone  21  is a metallic structural frame, in which carbon steel and stainless steel form a cladding structure. Since the vessel  20  is decreased in stiffness for the structural frame when heated at a temperature of about 500° C. or over, a cooling jacket  31  in which cooling water circulates is arranged on an outside of the vessel  20 , thereby maintaining the vessel  20  at a temperature of 300° C. or under, 
     In other words, the hot zone  21  is configured to keep high temperature proper to cause thermal conversion reaction of the reaction gas, while the vessel  20  surrounding the hot zone  21  is configured to have a separate cooling system  30  for structural stability. However, such a conventional configuration has low efficiency of thermal energy utilization since a lot of thermal energy escapes outward via the vessel  20 . Also, because the heater  13  has to additionally operate as much as loss of thermal energy transferred from the hot zone to the vessel, there is a problem of increasing power consumption. 
     Also, the reaction gas (STC+H 2 ) is supplied at high pressure through a plurality of inlet holes  11  formed in the center and outer circumference of the base plate  10  so that it can evenly circulate and cause the reaction within the hot zone  21 . At this time, the temperature of supplied reaction gas corresponds to an evaporation temperature of STC depending on supply pressure, and therefore a lot of thermal energy is needed for maintaining the hot zone  21  to have a temperature of about 900° C. to 1500° C. 
     Also, the cooling system  30  needs a cooling water circulating unit  32  for circulating cooling water to the cooling jacket  31  provided on the outside of the vessel  20 , a cooling unit  33  for cooling the cooling water increased in temperature while cooling the vessel  20  again through the cooling jacket  31 , and a tank and the like units for storing the cooling water, which are installed in the vicinity of a conversion apparatus. Accordingly, the cooling system  30  together with complicated piping occupies a large space, and the power consumption increases to drive a pump and the like units for circulating the cooling water. Also, enormous investment costs of establishing and managing the cooling system  30  increase. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is conceived to solve the forgoing problems, and an aspect of the present invention is to provide a hermetic container for thermal conversion reaction, in which a vessel is prevented from being heated at a limit temperature or over, and thus there is no need of a separate cooling system for cooling the vessel since reaction gas is supplied to a hot zone as it is heated by absorbing thermal energy escaping to the outside of the vessel when the reaction gas is supplied to the hot zone. 
     Another aspect is to provide a hermetic container for thermal conversion reaction, in which the reaction gas is supplied to the hot zone as it is heated by absorbing thermal energy, so that not only the temperature of the hot zone can be prevented from being rapidly lowered, but also power consumption of a heater can be reduced. 
     Still another aspect is to provide a hermetic container for thermal conversion reaction, in which a plurality of partition walls constituting a heat exchanger and a circulating passage connecting an inlet hole with the hot zone through a through hole formed in one end part or the other end part of the partition wall are arranged in a zigzag fashion, thereby enhancing a thermal exchanging efficiency. 
     Still another aspect is to provide a hermetic container for thermal conversion reaction, in which a spraying nozzle is provided for dispersing spraying pressure of reaction gas at a gas inlet side of the circulating passage connecting the inlet hole and the hot zone and at the same time evenly supplying the reaction gas up to a region between the spraying nozzle and another spraying nozzle adjacent thereto. 
     Still another aspect is to provide a hermetic container for thermal conversion reaction, in which heat exchange is carried out even in regions between plural spraying nozzles and a lower region of the circulating passage where the spraying nozzle is placed, thereby improving efficiency of heat exchange. 
     According to an exemplary embodiment, there is provided a hermetic container for thermal conversion reaction, including: a base plate; a vessel which, together with the base plate, forms a hermetic hot zone; a heater which is arranged in the hot zone; inlet and outlet holes through which reaction gas is supplied to and discharged from the hot zone; and a heat exchanger which is provided inside the vessel so that the reaction gas supplied to the hot zone via the inlet holes can absorb thermal energy transferred to the vessel to cool temperature of the vessel and at the same time be supplied to the hot zone as being heated. 
     The heat exchanger may include a circulating passage that circulates in a space between the vessel and the hot zone and connects the inlet holes and the hot zone. 
     The circulating passage may include a partition wall partitioning a space involving the inlet holes and adjacent to an inside of the vessel and a space involving the heater and the outlet holes, and a through hole formed on the partition wall as being spaced apart from the inlet hole so that the reaction gas supplied via the inlet hole can be supplied to the hot zone after exchanging heat while circulating in a space between the partition wall and the vessel). 
     The partition wall may be provided as two or more cylindrical shapes different in size so that a space between the space involving the inlet hole and adjacent to the inside of the vessel and the space involving the heater and the outlet hole can be partitioned into a plurality of layers, and is arranged such that a small partition wall is inserted in a large partition wall. 
     The through holes formed on the two or more partition walls may be alternately arranged with respect to the inlet hole to change a moving path of the reaction gas. 
     The partition wall may be shaped like a cylinder having an opened top, and the hermetic container further includes a cover finishing the tops of the partition walls and having an outer circumference adhered to the inside of the vessel. 
     The partition wall may include a material having thermal resistance to temperature raised by thermal energy transferred from the hot zone at a arranged position. 
     The hermetic container further include a spraying nozzle provided at a gas discharging side of the inlet hole and dispersing gas supplied to the heat exchanger. 
     The plural inlet holes may be formed at predetermined intervals on the base plate corresponding to a region between the partition wall and the vessel. 
     The spraying nozzle may include one end part connected to the inlet hole and receiving gas, and the other end part including a finished supply pipe, and at least one spraying hole laterally formed from the supplying pipe and discharging gas. 
     The spraying nozzle may include a guide spaced apart from the spraying hole and guiding the laterally sprayed gas to be induced downward. 
     The spraying nozzle may include one end part connected to the inlet hole and receiving gas, and the other end part including a finished supply pipe, and at least one spraying hole inclined downward from the supplying pipe and discharging gas. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects of the present invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view of a conventional converter that converts STC into TCS through thermal conversion; 
         FIG. 2  is a perspective view of a hermetic container for thermal conversion reaction according to a first exemplary embodiment; 
         FIG. 3  is an exploded perspective view of the hermetic container for thermal conversion reaction according to the first exemplary embodiment; 
       FIG,  4  is a front cross-sectional view of the hermetic container for thermal conversion reaction according to the first exemplary embodiment; 
         FIG. 5  is a plan cross-sectional view of the hermetic container for thermal conversion reaction according to the first exemplary embodiment; 
         FIG. 6  is a partial cut-open perspective view of a hermetic container for thermal conversion reaction according to a second exemplary embodiment; 
         FIG. 7  is a partial exploded perspective view of the hermetic container for thermal conversion reaction according to the second exemplary embodiment; 
         FIG. 8  is a front cross-sectional view of the hermetic container for thermal conversion reaction according to the second exemplary embodiment; 
         FIG. 9  is a perspective view of a hermetic container for thermal conversion reaction according to a third exemplary embodiment; 
         FIG. 10  is an exploded perspective view of the hermetic container for thermal conversion reaction according to the third exemplary embodiment; 
         FIG. 11  is a front cross-sectional view of the hermetic container for thermal conversion reaction according to the third exemplary embodiment; 
         FIG. 12  is an enlarged view of an “A” part in  FIG. 11 ; 
         FIG. 13  is a cross-sectional view of a spraying nozzle in a hermetic container for thermal conversion reaction according to another exemplary embodiment; and 
         FIG. 14  is a cross-sectional view of a hermetic container for thermal conversion reaction according to a forth exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Prior to description, elements will be representatively explained in a first embodiment and only different configurations will be described in another embodiment, in which like reference numerals refer to like elements throughout the embodiments. 
     Hereinafter, a hermetic container for thermal conversion reaction according to exemplary embodiments will be described with reference to accompanying drawings. 
     Among the accompanying drawings,  FIG. 2  is a perspective view of a hermetic container for thermal conversion reaction according to a first exemplary embodiment, and  FIG. 3  is an exploded perspective view of the hermetic container for thermal conversion reaction according to the first exemplary embodiment. 
     As shown therein, the hermetic container for thermal conversion reaction according to the first exemplary embodiment includes a base plate  110 , a vessel  120 , and a heat exchanger  130  provided on a side of the vessel  120 . In this exemplary embodiment, the hermetic container for thermal conversion reaction will be for example described as an STC-TCS converter that converts silicon tetrachloride (SiCl 4 , hereinafter referred to as ‘STC’) into trichlorosilane (SiHCl 3 , hereinafter referred to as ‘TCS’). 
     The base plate  110  is formed with an outlet hole  112  at the center thereof, and a plurality of inlet holes on the outer circumference thereof. Further, a heater  113  for generating heat when powered on is installed on the top of the base plate  110 . 
     The vessel  120  is assembled to the base plate  110  so as to form a hot zone  123  sealed from an exterior region. In this exemplary embodiment, the vessel  120  includes a side wall  121  and a cover  122  covering an upside of the side wall  121 . 
     The heat exchanger  130  is formed on an inner side of the side wall  121  of the vessel  120  so that the reaction gas (STC+H 2 ) introduced through an inlet hole  111  of the base plate  110  can absorb thermal energy from the side wall  121  of the vessel  120  and be supplied to the hot zone  123  as it is heated. The heat exchanger  130  includes a circulating passage  131  connecting the inlet hole  111  with the hot zone  123 . 
     In the present exemplary embodiment, cylindrical partition walls  132  different in a diameter from one another are concentrically arranged, and through holes  132   a  are alternately formed between one end part and the other end part of respective partition walls  132  with regard to positions of the inlet holes  111 , so that the circulating passage  131  can be arranged in a zigzag fashion. 
     That is, the reaction gas introduced into the circulating passage  131  through the inlet hole  111  positioned between the outer partition wall  132  among the plural partition walls  132  and the side wall  121  of the vessel  120  circulates zigzag in a space between the partition walls  132  via the through holes  132   a  of the partition walls  132 . Thus, the reaction gas absorbs thermal energy transferred to the vessel  120  and the partition wall  132 , so that the reaction gas supplied to the hot zone can be heated with thermal energy that may not only heat the vessel  120  but also escape to the outside of the vessel  120 , thereby improving efficiency of thermal energy utilization. 
     In the foregoing exemplary embodiment, the circulating passage  131  forms a zigzag passage as the through holes  132   a  of the partition walls  132  are misaligned with one another, but not limited thereto. Alternatively, any type of structure may be configured as long as it can increase a heat exchanging area or a heat exchanging time by branching or changing a moving path while the reaction gas moves along the circulating passage. 
     Also, in the case where the plurality of partition walls  132  are provided as above, thermal energy transferred to the partition wall  132  is varied depending on positions where the partition walls  132  are provided, i.e., distances from the heater, so that the respective partition walls  132  can be heated at different temperatures. For example, if the hot zone  123  has a temperature of about 1200° C. and the reaction gas supplied via the inlet hole  111  has a temperature of 80° C., the side wall  121  keeps a temperature of about 200° C. or under, and the partition walls  132  from the partition wall  132  facing the side wall  121  to the partition wall  132  facing the hot zone  123  are respectively heated at temperatures of about 300° C., 500° C. and 700° C. Therefore, the plurality of partition walls  132  have to be configured with materials having thermal resistances respectively corresponding to the temperatures heated at arranged positions. 
     Also, the plural inlet holes  111  of the base plate  110  are provided at neighboring intervals in order to supply the reaction gas having equal pressure with respect to a horizontal direction in a space between the vessel  120  and the outmost partition wall  132 . 
     Further, the drawings show that the through hole  132   a  is formed by penetrating the partition wall  132 , but not limited thereto. Alternatively, the through hole may be given in various forms for communicating both side spaces of the partition wall  132  with each other. For example, one end part of the partition wall  132  may be coupled to the base plate  110  or the cover  122 , and the other end part may be spaced apart at a predetermined space from the cover  122  or the base pate  110 , thereby using the space as the through hole. 
     In the foregoing exemplary embodiment, the vessel  120  includes the side wall  121  and the cover  122 , but not limited thereto. Alternatively, in the case of a bell-jar type vessel, the heat exchanger  130  provided inside the vessel  120  may include a partition wall  132  that has a shape corresponding to the inside of the vessel  120 , i.e., the same shape as the vessel  120  and spaced apart at a predetermined distance from the inside of the vessel  120 . In this case, the partition wall  132  may be arranged in plural and the through hole  132   a  may be formed to be misaligned with each other, thereby enhancing a thermal exchanging efficiency of the circulating passage  131 . 
     Now, operations of the foregoing hermetic container for thermal conversion reaction will be described according to the first exemplary embodiment. 
       FIG. 4  is a front cross-sectional view of the hermetic container for thermal conversion reaction according to the first exemplary embodiment, and  FIG. 5  is a plan cross-sectional view of the hermetic container for thermal conversion reaction according to the first exemplary embodiment. 
     First, as shown in  FIG. 4 , the side wall  121  of the vessel  120  is arranged on the outer circumference of the base plate  110 , and the cover  122  is arranged on the top of the side wall  121 , thereby forming the hermetic hot zone  123 . Then, the heater  113  provided on the base plate  110  is powered on and heats the hot zone 123 to have an internal temperature of about 900° C. to 1500° C. proper to the reaction. 
     In the state that the internal temperature of the hot zone  123  is raised as above, if STC and H2 are supplied through the inlet holes  111  of the base plate  110 , they are converted into TCS and HCl by thermal hydrogenation in the hot zone  123  and thus TCS and HCl are discharged through the outlet holes  112 . 
     At this time, the heat exchanger  130  is provided inside the side wall  121  of the vessel  120  and cools the side wall  121  surrounding the hot zone  123  by the circulating passage  131  connecting the inlet hole  111  and the hot zone  123  and at the same time raises the temperature of the reaction gas supplied to the hot zone  123 . 
     Particularly, the circulating passage  131  is formed by the partition walls  132  that has the bottom coupled to the base plate  110  between the inlet holes  111  and the heater  113 , the top coupled to the cover  122 , and the through hole  132   a  formed on the surface thereof and allowing the both side spaces to communicate with each other. The through holes  132   a  are alternately formed between one end part and the other end part of the partition wall  132  with respect to the inlet holes  111 , so that the inlet holes  111  and the hot zone  123  can be connected in a zigzag fashion. 
     The reaction gas introduced into the circulation passage  131  via the inlet holes  111  absorbs the thermal energy transferred to the vessel  120  and the partition wall  132  and cools the vessel  120  so that it can be supplied to the hot zone  123  as it is heated at the same time. 
     Thus, there is no need of a separate cooling system for cooling the vessel  120 , and loss of the thermal energy escaping to the outside of the vessel  20  is prevented, thereby offering an advantage of improving efficiency in thermal energy utilization. 
     Also, the reaction gas absorbs the thermal energy transferred to the side wall  121  of the vessel  120  and is thus supplied to the hot zone  123  as it is heated, so that not only the efficiency in thermal energy can be improved but also the power consumption of the heater  113  for maintaining the hot zone  123  to have a temperature proper to the reaction can be decreased. 
     Also, the circulating passage  131  is formed in a zigzag fashion by the through holes  132   a  alternately arranged between one end parts and the other end parts of the plural partition walls  132  with respect to the inlet holes  111 , thereby increasing a heat exchanging area between the reaction gas introduced into the circulating passage  131  via the inlet holes  111  and the vessel  120  and between the reaction gas and the partition wall  132 . 
       FIG. 5  shows a cross-section taken along line A-A′ of  FIG. 4 . As shown therein, the inlet holes  111  penetrating the outer circumference of the base plate  110  and positioned between the side wall  121  and the outer partition wall  132  are arranged in plural at regular intervals along the circumferential direction, so that the reaction gas can be introduced via the respective inlet holes  111  and supplied to the hot zone  123  through the circulating passage  131 . 
     Here, the inlet holes  111  are densely arranged at equal intervals, so that the reaction gas can be evenly supplied by equal pressure with regard to the whole area of the inlet side of the circulating passage  131 . Also, the reaction gas moves up or down by equal pressure with respect to the horizontal direction in each region of the circulating passage  131 , thereby preventing the side wall  121  and the partition walls  132  from rapidly increasing in temperature at a certain region. 
     Then, a hermetic container for thermal conversion reaction will be described according to a second exemplary embodiment. 
     Among the accompanying drawings,  FIG. 6  is a partial cut-open perspective view of the hermetic container for thermal conversion reaction according to the second exemplary embodiment, and  FIG. 7  is a partial exploded perspective view of the hermetic container for thermal conversion reaction according to the second exemplary embodiment. 
     As shown therein, in the hermetic container for thermal conversion reaction according to the second exemplary embodiment, the vessel  120  is a bell-jar type opened at one side, and the opened side is assembled to the base plate  110 , thereby internally forming a hot zone. 
     Also, the circulating passage  131  of the heat exchanger  130  provided inside the vessel  120  and connecting the inlet holes  111  and the hot zone  123  includes at least one cylindrical partition wall  132  arranged between the inlet holes  111  of the base plate  110  and the heater  113 , the through hole  132   a  formed at an end part opposite to the inlet holes  111  on the surface of the partition wall  132 , and the cover  133  having an outer circumference to be adhered to the inside of the vessel  120  and covering the top of the cylindrical partition wall  132 . 
     To improve the thermal exchanging efficiency of the circulating passage like the above-described exemplary embodiment, the plural cylindrical partition walls different in a diameter from one another may be provided, and the through holes formed on the respective partition walls may be alternately arranged with respect to the inlet holes, thereby forming a zigzag moving path (see  FIG. 6 ). 
     Meanwhile, the other elements except the vessel and the heat exchanger are the same as those of the foregoing exemplary embodiment, and thus repetitive descriptions thereof will be avoided as necessary. 
     Among the accompanying drawings,  FIG. 8  is a front cross-sectional view of the hermetic container for thermal conversion reaction according to the second exemplary embodiment. 
     As shown in  FIG. 8 , the heat exchanger  130  includes an upwardly opened cylindrical partition wall  132  arranged between the inlet holes  111  of the base plate  110  and the bell-jar type vessel  120 , the through hole  132   a  formed at a position spaced part from the inlet holes  111  on the surface of the partition wall  132  and allowing both side spaces to communicate with each other, and the cover  133  covering the top opened side of the partition wall  132  and having an outer circumference to be adhered to the inside of the vessel  120 . 
     Also, the plurality of partition walls  132  are different in size from one another, and divides a space between a space having opposite end parts supported by the cover  133  and the base plate  110  and including the inlet holes  111  adjacent to the inside of the vessel  120  and a space including the outlet holes  112  and the heater  113  into a plurality of layers. At this time, the plurality of partition walls  132  is formed with the through holes  132  at alternate positions with respect to the inlet holes  111 , so that the circulating passage  131  connecting the inlet hole  111  and the hot zone  123  can be formed in a zigzag fashion. 
     That is, in the state that the heat exchanger  130  is arranged inside the vessel  120  surrounding the hot zone  123 , the reaction gas is supplied via the inlet holes  111  to the hot zone  123  at the evaporation temperature of STC very lower than a temperature of about 900° C. to 1500° C. maintained in the hot zone  123 . At this time, since the reaction gas absorbs the thermal energy transferred to the vessel  120  and the partition wall  132  while passing through the zigzag circulating passage  131  connecting the inlet holes  111  and the hot zone  123 , there is no need of the conventional separate cooling system for cooling the vessel  120 . 
     Further, the reaction gas supplied at the evaporation temperature of STC very lower than the temperature of the hot zone  123  is supplied to the hot zone  123  as it is heated up to a temperature of about 500° C. to 500° C. while passing through the circulation passage  131  of the heat exchanger  130 , thereby preventing the temperature of the hot zone  123  from being rapidly lowered by the introduction of the reaction gas. Therefore, it is possible to additionally reduce the power consumption of the heater  113 . 
     Meanwhile, as described above, the number of partition walls  132  constituting the circulating passage  131  may be adjusted in consideration of the temperature of the reaction gas supplied to the hot zone  123 , loss of thermal energy escaping to the outside of the vessel  120 , thermal exchanging efficiency based on the material of the partition wall  132 , etc. 
     Below, a hermetic container for thermal conversion reaction according to a third exemplary embodiment will be described in detail with reference to accompanying drawings. 
     Among the accompanying drawings,  FIG. 9  is a perspective view of the hermetic container for thermal conversion reaction according to the third exemplary embodiment, and  FIG. 10  is an exploded perspective view of the hermetic container for thermal conversion reaction according to the third exemplary embodiment. 
     As shown therein, the hermetic container for thermal conversion reaction according to the third exemplary embodiment includes the base plate  110 , the vessel  120 , the heat exchanger  130  and a spraying nozzle  14 . This exemplary embodiment is the same as the foregoing exemplary embodiments except that the spraying nozzle  140  is provided in the inlet hole  111  of the base plate  110 , and thus repetitive descriptions thereof will be avoided as necessary. 
     The spraying nozzle  140  is provided in a gas discharging side of the inlet hole  111  and disperses a spraying direction of the reaction gas. The spraying nozzle  140  includes one end part coupled to the inlet hole  111  and the other end part that has a finished supplying pipe  141 , at least one spraying hole  142  laterally formed at the other end part of the supplying pipe  141  and allowing the reaction gas to be discharged, and a guide  143  spaced apart at a predetermined distance from the spraying hole  142  so that the reaction gas laterally sprayed through the spraying hole  142  can be guided downward. 
     From now on, operations of the hermetic container for the thermally conversion reaction according to the third exemplary embodiment will be described. 
     Among the accompanying drawings,  FIG. 11  is a front cross-sectional view of the hermetic container for thermal conversion reaction according to the third exemplary embodiment, and  FIG. 12  is an enlarged view of an “A” part in  FIG. 11 . 
     First, as shown in  FIG. 11 , the circulating passage  131  connecting the inlet holes  111  and the hot zone  123  is formed by the heat exchanger  130  arranged inside the vessel  120 . 
     Further, the plurality of partition walls  132  constituting the heat exchanger  130  and the through holes  132   a  formed on the partition walls  132  cause the circulating passage  131  connecting the inlet holes  111  and the hot zone  123  to form a zigzag moving path. 
     In this state, the reaction gas introduced via the inlet holes  111  at the evaporation temperature of STC very lower than the temperature of the hot zone  123  absorbs the thermal energy transferred to the vessel  120  and the partition wall  132  while passing through the zigzag circulating passage  131 , and is then supplied to the hot zone  123  as it is heated. 
     Particularly, the spraying nozzles  140  are respectively coupled to the discharging sides of the inlet holes  111  and disperse the reaction gas supplied to the circulating passage  131  of the heat exchanger  130  via the inlet hole  111 , thereby preventing the spraying pressure from being focused on a certain region. Also, the reaction gas is sprayed downward in the circulating passage  131 , so that heat exchange can be performed while the reaction gas is supplied even to a region between the adjacent spraying nozzles, thereby improving the efficiency in thermal exchange. 
     That is, the reaction gas supplied via the inlet holes  111  are respectively discharged from the supplying pipe  141  of the spraying nozzle  140  arranged in the gas discharging side of the inlet hole  111  and from the plurality of spraying holes  142  laterally formed at the other end part of the supplying pipe  141 , thereby dispersing supply pressure. Also, the guide  143  provided at a position spaced apart at a predetermined distance from the spraying hole  142  guides the reaction gas to be sprayed toward the bottom of the base plate  110 . 
     Accordingly, the reaction gas moves by equal pressure until reaching an upper region from a lower region of the circulating passage  131 , so that time to absorb thermal energy from the partition wall  131  and the vessel  120  can be extended. Further, the heat exchange is performed while the reaction gas changed in a supply direction from the both spraying nozzles  140  is supplied even between the adjacent spraying nozzles  140 , thereby offering an advantage of improving the efficiency of thermal conversion. 
     Next, another exemplary embodiment of the spraying nozzle in the hermetic container for thermal conversion reaction will be described. 
     Among the accompanying drawings,  FIG. 13  is a cross-sectional view of a spraying nozzle in a hermetic container for thermal conversion reaction according to another exemplary embodiment. 
     As shown therein, a spraying nozzle  140 ′ in this exemplary embodiment is different from the spraying nozzle  140  of the foregoing exemplary embodiment in that one end part is connected to the inlet hole  111  and the other end part includes a finished supplying pipe  141 , and at least one spraying hole  142  downwardly inclined from the other end part of the supplying pipe  141  and discharging the reaction gas. 
     If the reaction gas is supplied via the inlet holes  111  in the state that the spraying nozzle  140 ′ with this configuration according to this exemplary embodiment is arranged at a gas discharging side of the inlet hole  111  positioned between the vessel  120  and the partition wall  132 , the reaction gas is discharged downward in the circulating passage  131  through the plurality of spraying holes  142  inclined downward at the other end part of the supplying pipe  141  of the spraying nozzle  140 ′ 
     At this time, the reaction gas can be sprayed in various directions since there are the plural spraying holes  142 , and supplied downward in a lower region of the circulating passage  131  because the spraying hole  142  is inclined downward. Therefore, the reaction gas evenly moves to an upper region by pressure focused on the lower region of the circulating passage  131 , thereby prolonging time to absorb thermal energy transferred to the partition wall  132  and the vessel  120 . Further, the reaction gas is supplied to even a space between a pair of adjacent spraying nozzles  140 ′, the heat exchange is performed in the whole region between the partition wall  132  and the vessel  120 . Thus, this exemplary embodiment offers an advantage of improving the thermal exchanging efficiency. 
     Among the accompanying drawings,  FIG. 14  is a cross-sectional view of a hermetic container for thermal conversion reaction according to a forth exemplary embodiment. In this exemplary embodiment, the hermetic container for thermal conversion reaction will be for example described as a chemical vapor deposition (CVD) reactor for producing highgrade purity polycrystalline silicon. 
     As shown in  FIG. 14 , the hermetic container for thermal conversion reaction according to the fourth exemplary embodiment includes the base plate  110 , the vessel  120 , the heat exchanger  130  and the spraying nozzle  140 . 
     Here, the heater  113  provided on the base plate  110  may include a seed filament that resistively generates heat when receiving electric power and induces silicon to be deposited on an outer surface thereof. 
     Also, the circulating passage  131  of the heat exchanger  130  is arranged to surround the heater  113  and the outlet hole  112 , and includes a bell-jar type partition wall  132  partitioning a space involving the heater  113  and the outlet hole  112  and a space involving the inlet hole  111  and adjacent to the inside of the vessel  120 , and the through hole  132   a  formed on the partition wall  132  at an opposite side to the inlet hole  111 . 
     The other elements except the heater  113  and the circulating passage  131  are the same as those of the foregoing exemplary embodiments. Also, the spraying nozzle  140  installed at a part marked with “A” in  FIG. 14  is also provided in the same form as the spraying nozzle  140  of  FIG. 13  and the spraying nozzle  140 ′ of  FIG. 14 , and thus repetitive descriptions thereof will be avoided as necessary. 
     Operations of the hermetic container for thermal conversion reaction according to the fourth exemplary embodiment are as follows. The heater  113  is powered on and maintains its surface temperature of about 1100° C. as a typical reaction temperature. In this state, if the reaction gas (TCS+H 2 ) is supplied through the inlet hole  111 , silicon ingredients of the reaction gas are deposited on the external surface of the heater  113 , and hydrogen chloride 3HCl remaining after the reaction is discharged through the outlet hole  112 . 
     At this time, the reaction gas supplied through the inlet hole  111  is introduced into a space between the partition wall  132  and the vessel  120  and not only absorbs the thermal energy transferred to the vessel  120  and the partition wall  132  while circulating along the moving path of the circulating passage  131  but also absorbs thermal energy transferred to the vessel  120  and the partition wall  132  while being supplied to the hot zone  123  via the through hole  132   a  spaced apart from the inlet hole  111 . 
     Therefore, the reaction supplied at a temperature lower than the reaction temperature is supplied as it is heated, thereby reducing power consumption of the heater  113  for maintaining the hot zone  123  to have a high temperature. Also, the vessel  120  is cooled while the reaction gas absorbs the thermal energy transferred to the vessel  120  and the partition wall  132 , thereby offering an advantage that there is no need of a separate cooling system provided outside the vessel  120  in order to cool the vessel  120 , or the capacity or operation of the cooling system is minimized. 
     Further, the spraying nozzles  140  are respectively coupled to the discharging sides of the inlet holes  111 , so that the supply pressure of the reaction gas supplied to the circulating passage  131  of the heat exchanger  130  via the inlet hole  111  can be dispersed and the reaction gas can be sprayed downward in the circulating passage  131 . Thus, the heat exchange is performed while the reaction gas is supplied even to the lower region of the circulation passage  131  and a region between the pair of adjacent spraying nozzles, thereby improving the thermal exchanging efficiency. 
     As described above, there is provided a hermetic container for thermal conversion reaction, in which a vessel is prevented from being heated at a limit temperature or over, and thus there is no need of a separate cooling system for cooling the vessel since reaction gas is supplied to a hot zone as it is heated by absorbing thermal energy escaping to the outside of the vessel when the reaction gas is supplied to the hot zone. 
     Also, there is provided a hermetic container for thermal conversion reaction, in which the reaction gas is supplied to the hot zone as it is heated by absorbing thermal energy, so that not only the temperature of the hot zone can be prevented from being rapidly lowered, but also power consumption of a heater can be reduced. 
     Further, there is provided a hermetic container for thermal conversion reaction, in which a plurality of partition walls constituting a heat exchanger and a circulating passage connecting an inlet hole with the hot zone via a through hole formed in one end part or the other end part of the partition wall are arranged in a zigzag fashion, thereby enhancing a thermal exchanging efficiency. 
     Further, there is provided a hermetic container for thermal conversion reaction, in which a spraying nozzle is provided for dispersing spraying pressure of reaction gas at a gas inlet side of the circulating passage connecting the inlet hole and the hot zone and at the same time evenly supplying the reaction gas up to a region between the spraying nozzle and another spraying nozzle adjacent thereto. 
     Further, there is provided a hermetic container for thermal conversion reaction, in which heat exchange is carried out even in regions between plural spraying nozzles and a lower region of the circulating passage where the spraying nozzle is placed, thereby improving efficiency of heat exchange. 
     While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.