Patent Publication Number: US-2013239857-A1

Title: Swirl flow type pre-mixed low-pollution combustion apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Korean Patent Application No. 10-2012-0026861, filed on Mar. 16, 2012 in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Exemplary embodiments of the present invention relate to a waste gas purification apparatus, and more particularly, to a waste gas combustion apparatus to burn and process waste gases. 
     2. Description of the Related Art 
     In general, waste gases, which are generated in an industrial process such as a semiconductor or LCD (Liquid Crystal Display) manufacturing process or a chemical process, have highly toxic, explosive, and corrosive properties. Accordingly, the waste gases are released as they are into the atmosphere to allow environmental pollution to be caused. Therefore, a purification process should be necessarily performed to reduce an amount of noxious components contained in the waste gases below the allowable concentration. 
     As a method of processing the waste gases generated in the semiconductor manufacturing process or the like, there is a burning method of decomposing, reacting, or burning a pyrophoric gas with a hydrogen radical or the like in a high temperature combustion chamber, a wet method of dissolving a water-soluble gas in water while the water-soluble gas passes through the water stored in a water reservoir, or an adsorption method of purifying a toxic gas, which is not pyrophoric and soluble, in such a manner that the toxic gas is adsorbed onto an adsorbent by physical or chemical adsorption during passing through the adsorbent. 
     The burning method utilizes a combustion apparatus to burn the waste gases. There is, however, a problem in that, in the combustion apparatus of the related art, the waste gases generated in the semiconductor manufacturing process and N 2  gases used in a dry vacuum pump or the like are oxidized at a high temperature while being introduced into the combustion apparatus, thereby allowing large nitrogen oxides to be rapidly generated. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a swirl flow type pre-mixed low-pollution combustion apparatus that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
     An object of the present invention is to provide a waste gas combustion apparatus capable of achieving high efficiency and low pollution (namely, low NO x  and low CO). 
     Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     In accordance with one aspect of the present invention, a swirl flow type pre-mixed low-pollution combustion apparatus to process waste gases generated in an industrial process, such as a chemical process, a semiconductor manufacturing process, or an LCD manufacturing process, includes a combustion gas supply unit provided with a first combustion region, the first combustion region being a space where a flame is formed by supply of pre-mixed fuel gases, which are pre-mixed with diluted fuel gases, and support gases; and an ignition unit which includes an ignition device and is provided with a second combustion region, the second combustion region being a space where the flame formed in the first combustion region is diffused. 
     The combustion gas supply unit may be formed therein with the first combustion region, and may further include a gas nozzle member, which is provided with a pre-mixed fuel gas nozzle to inject the pre-mixed fuel gases and a support gas nozzle to inject the support gases. 
     The pre-mixed fuel gas nozzle may be constituted of a plurality of pre-mixed fuel gas nozzles which are disposed to be inclined toward one side with respect to a radial direction so that the pre-mixed fuel gases are rotated in the first combustion region, and the support gas nozzle may be constituted of a plurality of support gas nozzles which are disposed to be inclined toward one side with respect to a radial direction so that the support gases are rotated in the first combustion region. 
     The combustion apparatus may further include a waste gas supply unit provided with a guide pipe of which at least a portion is inserted into the first combustion region so as to supply the waste gases, and the guide pipe may be formed with a plurality of waste gas guide passages which are separated from one another. 
     The combustion apparatus may further include a by-product processing unit to remove powders which are fixed on the waste gas guide passages. 
     The combustion apparatus may further include a third combustion region adjacent to the second combustion region, and air may be introduced into the third combustion region from the outside. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a waste gas combustion apparatus according to an embodiment of the present invention; 
         FIG. 2  is a side view of the waste gas combustion apparatus shown in  FIG. 1 ; 
         FIG. 3  is a partial cutaway side view of the waste gas combustion apparatus shown in  FIG. 1 ; 
         FIG. 4  is a longitudinal cross-sectional view of the waste gas combustion apparatus shown in  FIG. 1 ; 
         FIG. 5  is an enlarged cross-sectional view of portion “A” in  FIG. 4 ; 
         FIG. 6  is a side view of a gas nozzle member shown in  FIG. 5 ; 
         FIG. 7  is a top view for explaining a fuel gas supply structure of the waste gas combustion apparatus shown in  FIG. 1 ; and 
         FIG. 8  is a top view for explaining a waste gas introduction structure of the waste gas combustion apparatus shown in  FIG. 1   
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present invention. The drawings are not necessarily to scale and in some instances, proportions may have been exaggerated in order to clearly illustrate features of the embodiments. 
       FIG. 1  is a perspective view illustrating a waste gas combustion apparatus according to an embodiment of the present invention,  FIG. 2  is a side view of the waste gas combustion apparatus shown in  FIG. 1 ,  FIG. 3  is a partial cutaway side view of the waste gas combustion apparatus shown in  FIG. 1 , and  FIG. 4  is a longitudinal cross-sectional view of the waste gas combustion apparatus shown in  FIG. 1 . With reference to  FIGS. 1 to 4 , the waste gas combustion apparatus, which is designated by reference numeral  100 , includes a waste gas supply unit  110 , a by-product processing unit  120 , a combustion gas supply unit  130 , an ignition unit  140 , and a body  150 . 
     The waste gas supply unit  110  includes a guide pipe  111 , and first to fourth injection pipes  112   a ,  112   b ,  112   c , and  112   d . The waste gas supply unit  110  supplies a combustion region defined within the waste gas combustion apparatus  100  with waste gases, which are a target to be treated, generated in a semiconductor manufacturing process, a chemical process, or the like. 
     The guide pipe  111  has a cylindrical shape which is elongated in an upward and downward direction. With reference to  FIG. 8 , the guide pipe  111  includes first to fourth waste gas guide passages  111   a ,  111   b ,  111   c , and  111   d  of which each extends vertically therein and is opened at opposite ends thereof, and which are separated from one another. Each of the waste gas guide passages  111   a ,  111   b ,  111   c , and  111   d  is individually formed for each type of waste gas to be introduced, so that it may be possible to solve a problem in that the waste gases are reacted with one another in the waste gas combustion apparatus. 
     The first to fourth injection pipes  112   a ,  112   b ,  112   c , and  112   d  are arranged around the side of the guide pipe  111  along the circumferential direction thereof in the form of protruding in an outwardly radial direction. The first injection pipe  112   a  is connected to the first waste gas guide passage  111   a , the second injection pipe  112   b  is connected to the second waste gas guide passage  111   b , the third injection pipe  112   c  is connected to the third waste gas guide passage  111   c , and the fourth injection pipe  112   d  is connected to the fourth waste gas guide passage  111   d . The waste gases are introduced into the waste gas guide passages  111   a ,  111   b ,  111   c , and  111   d  through the injection pipes  112   a ,  112   b ,  112   c , and  112   d , respectively. 
     The waste gas supply unit  110  has been described as including the four individual waste gas guide passages  111   a ,  11   b ,  111   c , and  111   d , and the four injection pipes  112   a ,  112   b ,  112   c , and  112   d  which respectively correspond to the same in the present embodiment. However, unlike the above-mentioned configuration, three or less or five or more individual waste gas guide passages and injection pipes which respectively correspond to the same may be used depending on types of waste gases which are the target to be treated. Of course, one waste gas guide passage may also be used in which the waste gas guide passages are integrated with one another. 
     The by-product processing unit  120  includes first to fourth cylinders  121   a ,  121   b ,  121   c , and  121   d , and piston rods  122   a  and  122   d  (only two piston rods being shown in the drawings) provided to respectively correspond to the same. The by-product processing unit  120  serves to remove powders (dust powders) which are fixed on inner walls of the respective waste gas guide passages  111   a ,  111   b ,  111   c , and  111   d  of the waste gas supply unit  110  during a combustion process. 
     The first to fourth cylinders  121   a ,  121   b ,  121   c , and  121   d  are coupled to an upper end  1111  of the guide pipe  111  of the waste gas supply unit  110 . The first cylinder  121   a  is located to correspond to the first waste gas guide passage  111   a , the second cylinder  121   b  is located to correspond to the second waste gas guide passage  111   b , the third cylinder  121   c  is located to correspond to the third waste gas guide passage  111   c , and the fourth cylinder  121   d  is located to correspond to the fourth waste gas guide passage  111   d . The piston rods  122   a  and  122   d  provided to correspond to the respective cylinders  121   a ,  121   b ,  121   c , and  121   d  are moved (perform linear and/or rotational movement) within the corresponding waste gas guide passages  111   a ,  111   b ,  111   c , and  111   d , respectively. The piston rods  122   a  and  122   d  are respectively coupled, at ends thereof, with removal members  123   a  and  123   d  which are able to scrub and remove the powders fixed on the inner walls of the waste gas guide passages  111   a ,  111   b ,  111   c , and  111   d . 
     Although the by-product processing unit  120  has been described as removing the powders fixed on the inner walls of the waste gas guide passages during the movement of the piston rods in the present embodiment, it may also be possible to remove the fixed powders by purging a heated nitrogen gas (N 2 ) and the like to each waste gas guide passage, other than the above-mentioned configuration. 
     The combustion gas supply unit  130  includes a case  131 , a gas nozzle member  132 , a pre-mixed fuel gas injection portion  136 , and a support gas injection portion  137 . The combustion gas supply unit  130  serves to supply fuel gases and support gases required for the combustion of the waste gases. 
     The case  131  has a hollow cylindrical shape and is located at an upper portion of the ignition unit  140 . The case  131  includes an upper wall  131   a , an outer side wall  131   b , and an inner side wall  131   c . The upper wall  131   a  is formed, at a central portion thereof, with a through hole  131   a   1  through which the gas nozzle member  132  passes. The outer side wall  131   b  extends downwards from the upper wall  131   a  so that a lower end of the outer side wall  131   b  is coupled to an upper end of the ignition unit  140 . The inner side wall  131   c  extends downwards from the upper wall  131   a  so that a lower end of the inner side wall  131   c  is coupled to the upper end of the ignition unit  140 . The inner side wall  131   c  is located at the inside of the outer side wall  131   b . A separate space  1311  is defined between the outer side wall  131   b  and the inner side wall  131   c . This space  1311  functions as a cooling water circulation space. 
     The gas nozzle member  132  has a cylindrical shape which extends in an upward and downward direction. The gas nozzle member  132  is provided therein with an inner space  1313 , which extends along a center line thereof in an upward and downward direction and passes through the gas nozzle member  132 . This inner space  1313  functions as a first combustion region which is a space where a flame is formed. The gas nozzle member  132  is accommodated, at a lower portion thereof, in an inner space of the inner side wall  131   c  while protruding, at an upper portion thereof, upwards of the upper wall  131   a  via the through hole  131   a   1  of the upper wall  131   a . The gas nozzle member  132  is abutted, at a lower end thereof, onto the upper end of the ignition unit  140 . The gas nozzle member  132  is provided, at an outer wall thereof, with separate flanges  133  of which each has an annular shape and protrudes in an outwardly radial direction. Each of the separate flanges  133  is provided with an annular groove  133   a  formed along the separate flange  133 . The annular groove  133   a  is fitted with a seal ring  133   b.  The seal ring  133   b  comes into contact with the inner side wall  131   c  to allow a space  1312  to be defined between the inner side wall  131   c  and the outer wall of the gas nozzle member  132 . The space  1312  is divided into a first upper gas space  1312   a  and a second lower gas space  1312   b.  The outer wall of the gas nozzle member  132  is provided with a plurality of pre-mixed fuel gas nozzles  134  to communicate the first gas space  1312   a  with the inner space  1313  of the gas nozzle member  132 , and a plurality of support gas nozzles  135  to communicate the second gas space  1312   b  with the inner space  1313  of the gas nozzle member  132 . Pre-mixed fuel gases are supplied to the inner space  1313  of the gas nozzle member  132  through the plural pre-mixed fuel gas nozzles  134 . The plural pre-mixed fuel gas nozzles  134  are disposed to be inclined toward one side with respect to the radial direction. Accordingly, the pre-mixed fuel gases are rotatably supplied when being introduced into the inner space  1313  of the gas nozzle member  132  through the plural pre-mixed fuel gas nozzles  134 , thereby being smoothly mixed. Consequently, the generation of thermal NO x  and CO may be reduced. The plural support gas nozzles  135  are disposed to be inclined toward one side with respect to the radial direction. Accordingly, the support gases are rotatably supplied when being introduced into the inner space  1313  of the gas nozzle member  132 , thereby allowing the diffusion combustion to be properly carried out and the temperature distribution to be uniformly maintained. The guide pipe  111  of the waste gas supply unit  110  is inserted and accommodated, at a lower portion thereof, in the inner space  1313  of the gas nozzle member  132 . The guide pipe  111  has a lower end  1112  which is located beneath the support gas nozzles  135 . 
     The pre-mixed fuel gas injection portion  136  passes through the outer side wall  131   b  and inner side wall  131   c  of the case  131  to be connected with the first gas space  1312   a.  The fuel gas injection portion  136  produces the fuel gases in a state of being diluted by mixing the combustible gases with the support gases, and then injects the pre-mixed fuel gases, which are produced, into the first gas space  1312   a.  There may be utilized a liquefied natural gas, a liquefied petroleum gas, a hydrogen gas, and the like, as the fuel gases. 
     The support gas injection portion  137  passes through the outer side wall  131   b  and inner side wall  131   c  of the case  131  to be connected with the second gas space  1312   b . The support gas injection portion  137  injects the support gases such as an oxygen gas into the second gas space  1312   b.    
     The ignition unit  140  includes a case  141 , an ignition device  142 , a display window  143 , and first and second combustion detection sensors  144   a  and  144   b.    
     The case  141  has a substantially hollow cylindrical shape and is located at an upper portion of the body  150 . The case  141  includes an upper wall  141   a , an outer side wall  141   b , an inner side wall  141   c , a flame guide wall  141   d , and a bottom plate  141   e  which faces the upper wall  141   a  and is formed, at a central portion thereof, with a through hole  141   e   1 . The upper wall  141   a  is formed, at a central portion thereof, with a through hole  141   a   1  which is communicated with the inner space  1313  of the gas nozzle member  132 . The outer side wall  141   b  extends downwards from the upper wall  141   a  so that a lower end of the outer side wall  141   b  is coupled to the bottom plate  141   e . The inner side wall  141   c  extends downwards from the upper wall  141   a  so that a lower end of the inner side wall  141   c  is coupled to the bottom plate  141   e . The inner side wall  141   c  is located at the inside of the outer side wall  141   b . A separate space  1411  is defined between the outer side wall  141   b  and the inner side wall  141   c . The flame guide wall  141   d  extends downwards from the upper wall  141   a  so that a lower end of the flame guide wall  141   d  is located in the through hole  141   e   1 formed at the bottom plate  141   e . A space  1411   c  is defined between the flame guide wall  141   d  and the inner side wall  141   c . The flame guide wall  141   d  is provided therein with a space  1411   d , which is connected with the inner space  1313  of the gas nozzle member  132 , an inner portion of the body  150 , and the space  1411   c  between the flame guide wall  141   d  and the inner side wall  141   c . This space  1411   d  functions as a second combustion region which is a space where the flame is diffused. The flame guide wall  141   d  enables the flame generated in the first combustion region  1313  to be excessively swirled so as to prevent the contact between the flame and the waste gas from being reduced. Furthermore, the flame guide wall  141   d  enables the flame to be properly diffused and to smoothly come into contact with the waste gas, thereby resulting in high processing efficiency of the waste gas. 
     The ignition device  142  passes through the outer side wall  141   b , inner side wall  141   c , and flame guide wall  141   d  of the case  141  to be connected with the space within the flame guide wall  141   d . The ignition device  142  supplies an ignition source to the space within the flame guide wall  141   d . The ignition device  142  includes an ignition plug and supplies CDA (Compressed Dry Air) to maintain a burner part in a dry state. When moisture is created in the burner part, powder fixation is activated. 
     The display window  143  passes through the outer side wall  141   b , inner side wall  141   c , and flame guide wall  141   d  of the case  141  to be connected with the space within the flame guide wall  141   d . The display window  143  allows an ignition phenomenon and a combustion phenomenon to be visually observed. The display window  143  has a fuzzy function because of being affected by the high temperature. 
     Each of the first and second combustion detection sensors  144   a  and  144   b  passes through the outer side wall  141   b , inner side wall  141   c , and flame guide wall  141   d  of the case  141  to be connected with the space within the flame guide wall  141   d . The first and second combustion detection sensors  144   a  and  144   b  detect the flames generated in the first and second combustion regions  1313   a  and  1313   b.    
     The bottom plate  141   e  is provided therein with a cooling water circulation space formed to enclose the through hole  141   e   1 . 
     The body  150  includes an outer case member  151 , an inner wall member  152 , and a plurality of air inlet portions  153   a  and  153   b.    
     The case member  151  has a substantially hollow cylindrical shape and includes an upper wall  151   a , a bottom plate  151   b , and a side wall  151   c . The upper wall  151   a  is coupled to a lower surface of the bottom plate  141   e  of the ignition unit  140 . The upper wall  151   a  is provided, at a central portion thereof, with a through hole  151   a   1 . The through hole  151   a   1  is formed larger than the through hole  141   e   1 of the bottom plate  141   e  of the ignition unit  140 . The bottom plate  151   b  faces the upper wall  151   a  and is provided, at a central portion thereof, with through hole  1511   b . The side wall  151   c  extends between the upper wall  151   a  and the bottom plate  151   b.    
     The inner wall member  152  has a hollow cylindrical shape which is opened at opposite ends thereof, and is coupled within the case member  151 . The opened upper end of the inner wall member  152  is connected to the through hole  151   a   1  of the upper wall  151   a , whereas the opened lower end of the inner wall member  152  is connected to the through hole  1511   b  of the bottom plate  151   b . The inner wall member  152  is provided, at a wall thereof, with a plurality of holes  1521  to communicate inner and outer portions of the inner wall member  152 . A space of the inner portion of the inner wall member  152  defines a third combustion region  1522 . 
     The plural air inlet portions  153   a  and  153   b  are mounted to the case member  151  and introduce outdoor air into the case member  151 . The air, which is introduced through the air inlet portions  153   a  and  153   b , is supplied to the third combustion region  1522  so as to uniformly distribute heat generated in the third combustion region  1522 , thereby reducing the generation of thermal NO x . 
     Although not shown, circulating water or the like flows around along the wall surface of the inner wall member  152  to flow downwards, and thus it may also be possible to prevent the fixation of the powders created during the combustion of the waste gases. 
     Hereinafter, an operation of the above-mentioned embodiment will be described with reference to  FIGS. 1 to 8 . 
     The waste gases generated in the industrial process, such as the chemical process, the semiconductor manufacturing process, or the LCD manufacturing process, and N 2  gases used in a dry vacuum pump or the like are individually supplied to the inner space  1313  of the gas nozzle member  132 , which is the first combustion region, through the respective waste gas guide passages  111   a ,  111   b ,  111   c , and  111   d  formed at the guide pipe  111  of the waste gas supply unit  110 , depending on the types of waste gases. In this case, the fuel gases are rotatably supplied to the first combustion region  1313  which is the space forming the flame by reaction of the fuel gases and oxidizer gases, thereby being smoothly mixed. Thus, the diluted fuel gases are pre-mixed and the generation of the thermal NO x  and CO is reduced. In addition, in the second combustion region  1411   d  which is a region of completely burning fuel gases which are not reacted in the first combustion region, the diffusion combustion is properly carried out and the temperature distribution to be uniformly maintained, thereby reducing the generation of the thermal NO x . Subsequently, the third combustion is performed with respect to the waste gases in the third combustion region  1522 . At this time, the air, which is introduced through the plural air inlet portions  153   a  and  153   b , allows heat to be uniformly distributed, thereby reducing the generation of the thermal NO x . The waste gases processed by the above-mentioned combustion process may be discharged through the through hole  1511   b  formed at the bottom plate  151   b.    
     As is apparent from the above description, the entire objects of the present invention may be achieved. Specifically, there is provided a combustion apparatus capable of achieving high efficiency and low pollution in such a manner that fuel gases and support gases are pre-mixed in a state where the fuel gases are diluted. 
     While the present invention has been described with respect to the illustrative embodiments, it will be apparent to those skilled in the art that various variations and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.