Patent Publication Number: US-11028724-B2

Title: Partial admission operation turbine apparatus for improving efficiency of continuous partial admission operation and method for operating turbine apparatus using same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the National Phase of PCT International Application No. PCT/KR2017/012263, filed on Nov. 1, 2017, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 10-2016-0171395, filed in the Republic of Korea on Dec. 15, 2016, all of which are hereby expressly incorporated by reference into the present application. 
     TECHNICAL FIELD 
     The present invention relates to a partial admission operation turbine apparatus, and more particularly, to a partial admission operation turbine apparatus for improving efficiency of a continuous partial admission operation in which a continuous partial admission operation is performed by using supercritical carbon dioxide (SCO 2 ) as a working fluid so that the performance and efficiency of a turbine can be improved, and a method for operating the turbine apparatus using the same. 
     BACKGROUND ART 
     In general, supercritical carbon dioxide (CO 2 ) power generation cycle technologies are high-efficiency power generation cycle technologies in which CO 2  compressed under a super-high pressure higher than a critical pressure is heated at a high temperature so as to drive a turbine, and recently, power generation technologies in which CO 2  of which supercritical conversion to a low critical point is easy and which has high density and low viscosity in a supercritical state, is used as a working fluid, have been developed. 
     Meanwhile, because in such supercritical power generation cycle technologies, a compression work can be significantly reduced compared to an existing air cycle, and the size of a turbine can be reduced to ⅕ of an organic rankine cycle (ORC) and equal to or less than 1/20 of a steam cycle, a turbo apparatus can be made small, and a thermal recovery temperature is fallen so that water at a room temperature can be used as a coolant, and the supercritical power generation cycle technologies can be applied to most heat sources such as waste heat recovery/independent heat sources, such as coal or CPS. Also, in the aforementioned supercritical power generation system, compatibility between CO 2  and an existing fluid is excellent even under high-temperature high-pressure conditions so that a higher turbine inlet temperature can be achieved than in a steam cycle and efficiency can be improved, and CO 2  that is a main cause of global warming can be reversedly utilized as the working fluid so that an eco-friendly power generation plant can be constructed. 
     However, in the aforementioned supercritical dioxide (SCO 2 ) cycle and ORC cycle, unlike in the existing steam rankine cycle or air Brayton cycle, due to high density or small heat source calories, the size of the turbine is reduced. Thus, when designs are carried out like the existing steam turbine or gas turbine, due to significantly reduced sizes, it is not possible to manufacture the turbine, or tolerance maintenance is not possible. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     The present invention provides a partial admission operation turbine apparatus in which a continuous partial admission (not full admission) operation can be performed for a turbine in a supercritical carbon dioxide (SCO 2 ) cycle and an organic rankine cycle (ORC) so that the difficulties in designing and manufacturing turbines can be resolved and the performance of the turbine can be improved, and a method for operating a turbine apparatus using the same. 
     Technical Solution 
     According to an aspect of the present invention, there is provided a partial admission operation turbine apparatus including a rotor portion rotatably coupled to a rotary shaft of a turbine and including a plurality of rotor blades, a nozzle portion fixedly coupled to the rotary shaft in front of the rotor portion and guiding and supplying a working fluid to the rotor blades through a plurality of nozzle blades, and an inlet disk coupled to the rotary shaft in front of the nozzle portion in a plate shape and having a plurality of admission holes formed therein so as to supply the working fluid to the nozzle portion to partially admit the working fluid into the nozzle portion, wherein each of the admission holes is formed to have at least two different passage cross-sectional areas, so that the opening and closing of the admission holes are controlled according to operating flow rate conditions to control a partial admission ratio of the working fluid supplied to the nozzle portion. 
     According to another aspect of the present invention, there is provided a method for operating a partial admission operation turbine apparatus, the method including being ready for operation of a partial admission operation turbine apparatus including a rotor portion rotatably coupled to a rotary shaft of a turbine and including a plurality of rotor blades, a nozzle portion fixedly coupled to the rotary shaft in front of the rotor portion and guiding and supplying a working fluid to the rotor blades through a plurality of nozzle blades, and an inlet disk coupled to the rotary shaft in front of the nozzle portion in a plate shape and having a plurality of admission holes formed therein so as to supply the working fluid to the nozzle portion to partially admit the working fluid into the nozzle portion, wherein each of the admission holes is formed to have at least two different passage cross-sectional areas, and controlling a partial admission ratio of the working fluid supplied to the nozzle portion by opening and closing the admission holes according to set operating flow rate conditions. 
     Effects of the Invention 
     A partial admission operation turbine apparatus for improving the efficiency of a continuous partial admission operation and a method for operating the turbine apparatus using the same according to the present invention provide the following effects. 
     First, a continuous partial admission operation is performed in a supercritical carbon dioxide (SCO 2 ) cycle and an organic rankine cycle (ORC) and a supercritical power generation system so that the difficulties in designing and manufacturing turbines can be resolved. 
     Second, a plurality of admission holes having different passage cross-sectional areas are formed so that a partial admission ratio can be controlled according to operating conditions, the performance of a turbine operated by continuous partial admission can be improved, and even if the operating flow rate conditions change in the same cycle, it is possible to operate the same turbine with high efficiency. 
     Third, the shapes of nozzle blades are differently formed for each of the admission holes having different passage cross-sectional areas so that passage flow rates can be controlled and thus the efficiency of the turbine apparatus can be improved. 
     Fourth, the shapes of nozzles and rotors having high costs in developing and manufacturing are fixed to one shape, and only the area of an inlet is differently formed so that one turbine can be used for various capacities and thus costs can be reduced. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a partial admission turbine apparatus according to an embodiment of the present invention. 
         FIG. 2  is a front view illustrating an inlet disk of the partial admission turbine apparatus of  FIG. 1 . 
         FIG. 3  is a view illustrating the shapes of nozzle blades of a nozzle portion of  FIG. 1 . 
         FIG. 4  is a front view illustrating a partial admission turbine apparatus according to another embodiment of the present invention. 
     
    
    
     MODE OF THE INVENTION 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     Referring to  FIG. 1 , a partial admission operation turbine apparatus  400  according to an embodiment of the present invention in which the efficiency of a continuous partial admission operation can be improved and a continuous partial admission (not full admission) operation is performed by using a working fluid in a supercritical state, in particular, supercritical carbon dioxide (SCO 2 , including gas or steam) as the working fluid so that the performance and efficiency of the turbine can be improved, includes a rotor portion  100 , a nozzle portion  200 , and an inlet disk  300 . 
     The rotor portion  100  is rotatably coupled to a rotary shaft (not shown) installed within a casing (not shown), includes a plurality of rotor blades (buckets)  110  and is rotated by an introduced working fluid. 
     The nozzle portion  200  is fixedly coupled to the rotary shaft in front of the rotor portion  100  and includes a plurality of nozzle blades  210 , allows the working fluid to flow between the nozzle blades  210 , guides and supplies the working fluid to the rotor blades  110 . Here, the rotor portion  100  and the nozzle portion  200  correspond to configurations of a nozzle (stator) and a rotor (bucket) of well-known turbine, respectively, and thus a detailed description thereof will be omitted. 
     The inlet disk  300  has a plate shape, is coupled to the rotary shaft in front of the nozzle portion  200  and has a plurality of admission holes  310 ,  320 , and  330  for supplying the working fluid to the nozzle portion  200  formed therein so that the working fluid can be partially admitted into the nozzle portion  200  through the admission holes  310 ,  320 , and  330 . 
     Referring to  FIG. 2 , the admission holes  310 ,  320 , and  330  are formed to have at least two different passage cross-sectional areas so that opening and closing of the admission holes  310 ,  320 , and  330  are optionally controlled according to operating flow rate conditions and thus a partial admission ratio of the working fluid supplied to the nozzle portion  200  can be controlled. 
     Thus, the partial admission operation turbine apparatus  400  enables an operation with high efficiency with the same turbine even if the operating flow rate conditions change in the same cycle, and the shapes of the nozzle blades  210  and the rotor blades  110  having high costs in developing and manufacturing are fixed to one shape, and only the passage cross-sectional areas of the admission holes  310 ,  320 , and  330  into which the working fluid is introduced, are differently formed so that one turbine can be used for various capacities and thus costs can be reduced. 
     Here, the inlet disk  300  includes three admission holes  310 ,  320 , and  330  having different passage cross-sectional areas formed therein in the drawings. However, this is just an embodiment, and of course, the number of admission holes may be diverse according to designs. 
     Meanwhile, the nozzle blades  210  may form differently a flow path passage area of the working fluid that flows between the nozzle blades  210  in response to at least two different passage cross-sectional areas of the admission holes  310 ,  320 , and  330  so that efficiency can be improved in response to the passage cross-sectional areas of the admission holes  310 ,  320 , and  330 . 
     To this end, the nozzle blades  210  form differently thickness ratios/chord lengths in response to at least two different passage cross-sectional areas of the admission holes  310 ,  320 , and  330 , as shown in  FIG. 3 , so that separation distances (pitches) d 1 , d 2 , and d 3  between the adjacent nozzle blades  210  are differently formed and thus the flow path passage area of the working fluid that passes between the nozzle blades  210  can be differently formed. 
     Regarding this in detail, in the nozzle blades  210 , the smaller the passage cross-sectional areas of the admission holes  310 ,  320 , and  330 , the shorter the separation distances between the nozzle blades  210 , and the larger the passage cross-sectional areas of the admission holes  310 ,  320 , and  330 , the longer the separation distances between the nozzle blades  210  so that the flow path passage area can be increased and a flow rate can be obtained. 
     Regarding this in detail by referring to  FIG. 3 , (a) of  FIG. 3  illustrates nozzle blades  211  that correspond to admission holes  330  having the largest passage cross-sectional area in  FIG. 2 , and the thickness ratio t 1  of the nozzle blades  211  is reduced so that a separation distance d 1  between the nozzle blades  211  is increased and thus, the flow path passage area can be increased, and conversely, regarding admission holes  310  having the smallest passage cross-sectional area, as shown in (c) of  FIG. 3 , the thickness ratio t 3  of nozzle blades  213  is increased and thus, a separation distance d 2  between the nozzle blades  213  can be decreased and thus, the flow path passage area can be decreased. (b) of  FIG. 3  illustrates nozzle blades  212  that correspond to admission holes  320  of  FIG. 2 , and the thickness ratio is larger than that of (a) of  FIG. 3  and is smaller than that of (c) of  FIG. 3 , and d 2  represents a separation distance, and t 1  represents a thickness. 
     Meanwhile, the nozzle blades  210  are formed so that separation distances between the nozzle blades  210  are decreased as the passage cross-sectional areas of the admission holes  310 ,  320 , and  330  are decreased and separation distances between the nozzle blades  210  are increased as the passage cross-sectional areas of the admission holes  310 ,  320 , and  330  are increased. However, this is just an exemplary embodiment, and of course, there may be various modifications according to designs, where, as the passage cross-sectional areas of the admission holes  310 ,  320 , and  330  are decreased, the thickness ratio of the nozzle blades  210  are decreased so that the flow path passage area of the nozzle portion  200  can be obtained. 
     In the partial admission operation turbine apparatus  400 , in order to control a partial admission ratio of the working fluid by optionally controlling the opening and closing of the admission holes  310 ,  320 , and  330  according to operating flow rate conditions, although not shown, a control disk having the same flat surface shape as that of the inlet disk  300 , having control holes formed therein and being rotatable may be installed at a rear surface of the inlet disk  300 , and the control disk may be rotated to optionally open and close the admission holes  310 ,  320 , and  330  or the flow path passage area may be changed. 
     Furthermore, the partial admission operation turbine apparatus  400  may include a flow rate control unit (not shown) so as to control a partial admission ratio of the working fluid supplied to the nozzle portion  200 , thereby controlling the supply flow rate of the working fluid in response to the passage cross-sectional areas of the admission holes  310 ,  320 , and  330 . 
     The flow rate control unit includes a plurality of supply lines for supplying the working fluid according to positions of the admission holes  310 ,  320 , and  330 , a plurality of flow rate control valves installed in the plurality of supply lines, and a controller for controlling the operation of the flow rate control valves in response to the admission holes  310 ,  320 , and  330 . 
     In this case, the controller controls the operation of the flow rate control valves in response to the passage cross-sectional areas of the admission holes  310 ,  320 , and  330  according to operating conditions and cycle designs and controls the supply flow rate of the working fluid so as to control the partial admission ratio of the working fluid. 
     As described above, a method for operating a turbine apparatus using the partial admission operation turbine apparatus  400  includes being ready for operation of the partial admission operation turbine apparatus  400 , opening and closing the admission holes  310 ,  320 , and  330  according to set operating flow rate conditions so as to control the partial admission ratio of the working fluid supplied to the nozzle portion  200 , wherein the making of the partial admission operation turbine apparatus  400  being ready for operation includes differently forming separation distances between the nozzle blades in response to the passage cross-sectional areas of the opened admission holes  310 ,  320 , and  330  so as to control the supply flow rate. In this case, in the nozzle blades  210 , preferably, the smaller the passage cross-sectional areas of the admission holes  310 ,  320 , and  330 , the shorter the separation distances between the nozzle blades  210 . Furthermore, by using the flow rate control unit, the controller controls the operation of the flow rate control valves in response to the passage cross-sectional areas of the admission holes  310 ,  320 , and  330  so that the supply flow rate of the working fluid can be controlled. 
       FIG. 4  illustrates a partial admission operation turbine apparatus according to another embodiment of the present invention. Referring to  FIG. 4 , the partial admission operation turbine apparatus includes inlet disks  300   a  and  300   b , which may be optionally installed at an inlet of a turbine to be mounted and have a plurality of admission holes  310 ,  320  and  330  formed therein so that the working fluid can be partially admitted into the nozzle portion, and an opening/closing unit  350  that optionally opens and closes the admission holes  310 ,  320 , and  330  according to designs. 
     The inlet disks  300   a  and  300   b  have plate shapes and include a plurality of admission holes  310 ,  320 , and  330  formed therein so as to supply the working fluid to the nozzle portion of the turbine, and the plurality of admission holes  310 ,  320 , and  330  are formed to have at least two different passage cross-sectional areas so that the working fluid can be partially admitted into the nozzle portion. 
     The opening/closing unit  350  opens or closes the plurality of admission holes  310 ,  320 , and  330  optionally according to a turbine to be installed and a turbine to be mounted, including the flow rate of the working fluid. The opening/closing unit  350  has a plate shape and includes opening/closing covers  351  and  352 , which are coupled to the front surfaces or rear surfaces of the inlet disks  300   a  and  300   b  corresponding to the admission holes  310 ,  320 , and  330 . Here, although not shown, the opening/closing covers  351  and  352  may be coupled to the inlet disks  300   a  and  300   b  by using various methods such as bolt fastening, welding, or the like, and a well-known coupling method may be applied to a detailed description thereof and thus, the detailed description thereof will be omitted. 
     In the drawings, (a) and (b) of figure respectively illustrate cases where the admission holes  310 ,  320 , and  30  are optionally closed using the opening/closing covers  351  and  352 , and (a) illustrates the case where the flow rate of the working fluid is larger than that of (b) or the opened inlet area of the admission holes  310 ,  320 , and  330  are increased in consideration of designs, etc. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, a turbine that can be operated through continuous partial admission can be designed and manufactured.