Patent Publication Number: US-2023143335-A1

Title: Air supply apparatus for a ship, ship including the same, and method for supplying air to an air lubrication device

Description:
TECHNICAL FIELD 
     Embodiments of the present disclosure relate to an air supply apparatus of an air lubrication type ship for reducing water friction resistance. Further, embodiments of the present disclosure relate to a method of supplying air to an air lubrication device of a ship. 
     BACKGROUND 
     Generally, a ship receives friction resistance of water during marine navigation on its submerged surface of the ship’s bottom. Especially for large ships, e.g. cargo ships, a large portion of the ship’s hull resistance of results from friction resistance generated by relative flow of outside water at the ship’s bottom. 
     To reduce ship’s hull friction resistance air lubrication can be used, particularly by discharging air into surroundings of the ship’s hull. The reduction of friction resistance has a large fuel economy improving effect, and thus represent effective means to reduce the CO 2  emission of the ship. 
     In the state of the art, there are various systems and approaches for the production of air bubbles for the hull lubrication. For instance, for the generation of air bubbles for hull lubrication, the prior art teaches direct usage of exhaust gas of the driving engine or to use separate electrical compressors or blowers. However, the known systems for hull lubrication have some disadvantages, for example in terms of energy consumption and efficiency. 
     Accordingly, in view of the above, there is a demand for improved air supply apparatuses for ships as wells as for improved methods of supplying air to an air lubrication device of ships which at least partially overcome the problems of the state of the art. 
     SUMMARY 
     In light of the above, an air supply apparatus for a ship and a method of supplying air to an air lubrication device of a ship according to the independent claims are provided. Further aspects, advantages, and features are apparent from the dependent claims, the description, and the accompanying drawings. 
     According to an aspect of the present disclosure, an air supply apparatus for a ship is provided. The air supply apparatus includes a first turbocharger having a first compressor and a first turbine being drivable by exhaust gas provided from one or more engines. The first compressor is coupled to the first turbine via a transmission configured for changing a speed of the first compressor. Additionally, the air supply apparatus includes an air lubrication device for resistance reduction of the ship. The first compressor is connected with the air lubrication device for supplying air to the air lubrication device. 
     Accordingly, the air supply apparatus of the present disclosure is improved compared to conventional apparatuses used for air lubrication type ships. In particular, embodiments of the air supply apparatus as described herein are improved with respect to energy efficiency. More specifically, by providing an air supply apparatus with a first turbocharger having a transmission coupling the first turbine with the first compressor for supplying air to the air lubrication device, the amount of air supplied to the air lubrication device can be controlled by using the transmission. More specifically, the first turbocharger, particularly the first compressor, is employed to compress low pressure air which subsequently is fed to the air lubrication device for air bubble generation under the vessel’s hull to reduce water-hull friction of a ship. Less friction for the vessel’s hull results in an overall reduction of energy usage of the ship. Accordingly, for example by employing the transmission to increase the speed of the first compressor compared to the speed of the first turbine the amount of air supplied to the air lubrication device can be increased resulting in an increased bubble generation under the vessel’s hull. Thus, compared to the state of the art, a higher reduction of water-hull friction of the ship can be achieved. As result thereof, the overall reduction of energy usage of the ship can be reduced such that savings of fuel can be achieved resulting in a reduction of the overall operation costs. 
     Thus, according to a further aspect of the present disclosure, a ship including an air supply apparatus according to any embodiments described herein is provided. 
     According to another aspect of the present disclosure, a method of supplying air to an air lubrication device of a ship is provided. The method includes driving a first turbocharger by using exhaust gas from one or more engines. Additionally, the method includes changing a speed of a first compressor of the first turbocharger by using a transmission coupled to a first turbine and to the first compressor of the first turbocharger. Further, the method includes supplying air from the first compressor of the first turbocharger to the air lubrication device. 
     Accordingly, it is to be understood that embodiments of the present disclosure provide for an air supply apparatus, a ship including the air supply apparatus, and a method of supplying air to an air lubrication device of the ship, which are improved with respect to energy efficiency such that operation costs can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following: 
         FIG.  1    shows a schematic view of an air supply apparatus according to embodiments described herein; 
         FIGS.  2  to  8    show schematic views of an air supply apparatus according to further embodiments described herein; 
         FIG.  9   a    shows a flowchart for illustrating a method of supplying air to an air lubrication device of a ship according to embodiments described herein; and 
         FIGS.  9   b  and  9   c    show flowcharts for illustrating a method of supplying air to an air lubrication device of a ship according to further embodiments described herein. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations. 
     Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment can apply to a corresponding part or aspect in another embodiment as well. 
     With exemplary reference to  FIG.  1   , an air supply apparatus  100  according to the present disclosure is described. According to embodiments, which can be combined with other embodiments described herein, the air supply apparatus  100  includes a first turbocharger  130  having a first compressor  131  and a first turbine  132 . The first turbine  132  is drivable by exhaust gas provided from one or more engines  120 . In this regard, it is to be noted, that “drivable by exhaust gas” can be understood in that exhaust gas is provided for driving. Accordingly, the first turbine  132  may be connected to the one or more engines  120 , e.g. by one or more pipes, such that the one or more engines  120  can supply exhaust gas to the first turbine  132 . The one or more engines  120  may be turbocharged. Accordingly, it is to be understood that the exhaust gas supplied from the one or more engines  120  to the first turbine  132  can already be expanded in one or more turbochargers of the one or more engines  120 . The first compressor  131  is coupled to the first turbine  132  via a transmission  133  configured for changing a speed of the first compressor  131 . In particular, the transmission  133  can be configured for varying a speed of the first compressor  131 . For example, the transmission  133  can be configured for increasing the speed of the first compressor  131  compared to the speed of the first turbine  132 . Additionally or alternatively, the transmission  133  can be configured for decreasing the speed of the first compressor  131  compared to the speed of the first turbine  132 . Further, as exemplarily shown in  FIG.  1   , the air supply apparatus  100  includes an air lubrication device  140  for resistance reduction of the ship. The first compressor  131  is connected with the air lubrication device  140 , particularly via a second air supply pipe  17 , for supplying air to the air lubrication device  140 . 
     Accordingly, beneficially an air supply apparatus with improved efficiency is provided. In particular, by providing a first turbocharger with a transmission as described herein has the advantage that the speed of the first compressor used for supplying air to the air lubrication device can be varied, and thus the amount of air supplied to the air lubrication device can be adjusted. For example, by using the transmission to increase the speed of the first compressor, the amount of air supplied to the air lubrication device can be increased. Accordingly, by decreasing the speed of the first compressor by means of the transmission, the amount of air supplied to the air lubrication device can be decreased. Hence, the amount of air supplied to the air lubrication device can be controlled on demand. 
     For example, by increasing the speed of the first compressor compared to the first turbine by means of the transmission provided there between, the efficiency of the first compressor for supplying air to the air lubrication device can be increased. Consequently, the effectivity of the air lubrication device can be improved, resulting in an increased bubble generation under the vessel’s hull and thus a higher reduction of water-hull friction of the ship. As result thereof, the overall reduction of energy usage of the ship can be reduced such that savings of fuel can be achieved resulting in a reduction of the overall operation costs. 
     According to embodiments, which can be combined with other embodiments described herein, the transmission  133  can be a mechanical transmission, an electrical transmission, a pneumatic transmission or a hydraulic transmission. According to an example, which can be combined with other embodiments described herein, the transmission  133  includes a generator and an electric motor. 
     It is to be understood, that a transmission as described herein, e.g. the first transmission  133  and/or the second transmission  136  described in the following, can be configured to be variable. In other words, the first transmission  133  and/or the second transmission  136  can have a variable transmission ratio. Accordingly, a transmission as described herein may be configured for providing a changeable transmission ratio. Thus, the speed of the first compressor  131  and/or the second compressor  135  can beneficially be adjusted and controlled during operation of the ship, i.e. during operation of the one or more engines  120 , particularly independently from the speed of the connected turbine, e.g. the first turbine  132  and/or the second turbine  134 , as described herein. 
     With exemplary reference to  FIG.  2   , according to embodiments, which can be combined with other embodiments described herein, the air supply apparatus  100  further includes a second turbine  134  in parallel to the first turbine  132 . As exemplarily shown in  FIG.  2   , the first turbine  132  and the second turbine  134  can be coupled to the first compressor  131  via the transmission  133 . 
     With exemplary reference to  FIG.  3   , according to embodiments, which can be combined with other embodiments described herein, the air supply apparatus further includes a second turbocharger  137  having a second compressor  135  and a second turbine  134 . The second turbine  134  is drivable by exhaust gas provided from the one or more engines  120 . Accordingly, the second turbine  134  may be connected to the one or more engines  120 , e.g. by one or more pipes, such that the one or more engines  120  can supply exhaust gas to the second turbine  134 . Additionally or alternatively, the second turbine  134  can be drivable by exhaust gas provided from the first turbine  132 . Accordingly, the second turbine  134  may be connected to the first turbine  132 , e.g. by one or more pipes, such that the first turbine  132  can supply exhaust gas to the second turbine  134 . As exemplarily shown in  FIG.  3   , the second compressor  135  is connected with the air lubrication device  140 , particularly via a third air supply pipe  19 , for supplying air to the air lubrication device  140 . 
     According to another optional implementation, which can be combined with other embodiments described herein, the second turbine  134  may be drivable by compressed air supplied from the first air supply pipe  16 , as exemplarily shown in  FIGS.  5  to  8   , to the second turbine  134 . Accordingly, it is to be understood that an air supply pipe (not explicitly shown in the figures) from the third compressor  111  to the second turbine  134  may be provided. Similarly, according to another example, which can be combined with other embodiments described herein, the first turbine  132  may be drivable by compressed air supplied from the first air supply pipe  16  (shown in  FIGS.  5  to  8   ) to the first turbine 2 Accordingly, it is to be understood that an air supply pipe (not explicitly shown in the figures) from the third compressor  111  to the first turbine  132  may be provided. 
     As exemplarily shown in  FIG.  3   , typically the second compressor  135  is coupled to the second turbine  134  via a further transmission  136 . The further transmission  136  is configured for changing a speed of the second compressor  135 . 
     In particular, the further transmission  136  can be configured for varying a speed of the second compressor  135 . For example, the further transmission  136  can be configured for increasing the speed of the second compressor  135  compared to the speed of the second turbine  134 . Additionally or alternatively, the further transmission  136  can be configured for decreasing the speed of the second compressor  135  compared to the speed of the second turbine  134 . 
     According to embodiments, which can be combined with other embodiments described herein, the further transmission  136  can be a mechanical transmission, an electrical transmission, a pneumatic transmission or a hydraulic transmission. According to an example, which can be combined with other embodiments described herein, the further transmission  136  includes a generator and an electric motor. 
     With exemplary reference to  FIGS.  4  to  8   , according to embodiments, which can be combined with other embodiments described herein, the air supply apparatus further includes a third turbocharger  110  having a third compressor  111  and a third turbine  112 . For example, the third turbocharger  110  can be a turbocharger or several turbochargers for charging the one or more engines  120 . In this regard, it is to be noted that the third turbocharger  110  shown in the figures may represent one or more turbochargers. Accordingly, it is to be understood that the one or more engines  120  may be charged or not (i.e. uncharged). As exemplarily shown in  FIG.  4   , the third turbine  112  is connected with an exhaust gas receiver  122  of the one or more engines  120  via a first exhaust gas pipe  11 . Accordingly, it is to be understood, that typically the turbocharger of the air supply apparatus according to embodiments described herein, particularly the first turbocharger  130 , is a separate turbocharger not employed for charging the engine. In other words, the first turbocharger  130  can be a secondary turbine-compressor pair provided in addition to a turbocharger for charging the engine. In particular, according to embodiments described herein which can be combined with other embodiments described herein, no mechanical force is taken from an engine’s turbocharger main turbine (e.g. the third turbine  112 ) to the air supply apparatus. 
     According to embodiments, which can be combined with other embodiments described herein, the first exhaust gas pipe  11  can be connected to a flow controller  160  for controlling an exhaust gas flow provided from the exhaust gas receiver  122  to the third turbine  112 , as exemplarily shown in  FIG.  8   . In particular, the flow controller  160  may be provided in a first bypass piping  13  bypassing the third turbine  112 . 
     With exemplary reference to  FIG.  8   , according to embodiments, which can be combined with other embodiments described herein, the first turbine  132  can be connected with the third turbine  112  via a second exhaust gas pipe  12 . The second exhaust gas pipe  12  can be connected to a bypass valve  170  for controlling an exhaust gas flow provided from the third turbine  112  to the first turbine  132 . In particular, the bypass valve  170  may be provided in a second bypass piping  14  bypassing the first turbine  132 . 
     As exemplary shown in  FIGS.  4  to  8   , according to embodiments, which can be combined with other embodiments described herein, the third compressor can be connected with an air receiver  121  of the one or more engines  120  via a first air supply pipe  16 . In particular, as exemplarily shown in  FIG.  8   , the first air supply pipe  16  includes a charge air cooler  150 . 
     With exemplary reference to  FIG.  8   , according to embodiments, which can be combined with other embodiments described herein, a further flow controller  161  may be provided downstream of the first turbine  132  of the first turbocharger. The piping in which the further flow controller  161  is provided can be connected via an exhaust gas connection  20  to the exhaust gas outlet piping  15 . The exhaust gas outlet piping  15  may be part of an exhaust system. The exhaust system can include an exhaust gas aftertreatment apparatus and/or a silencer before the exhaust gas is released to the environment. In this regard, it is to be noted that an exhaust gas aftertreatment apparatus and/or a silencer may also be provided in the other embodiments described herein. 
     Accordingly, from  FIGS.  1  to  8    it is to be understood, that according to another aspect of the present disclosure a ship  200  including an air supply apparatus according to any embodiments described herein is provided. Thus, a ship with a more energy efficient system for water-hull friction reduction can be provided, such that the overall operation costs can be reduced. 
     With exemplary reference to the flowchart shown in  FIG.  9   a   , a method  300  of supplying air to an air lubrication device of a ship according to the present disclosure is described. 
     According to embodiments, which can be combined with other embodiments described herein, the method  300  includes driving (represented by block  310  in  FIG.  9   a   ) a first turbocharger  130  by using exhaust gas from one or more engines  120 . Additionally, the method includes changing (represented by block  320  in  FIG.  9   a   ) a speed of a first compressor  131  of the first turbocharger  130  by using a transmission  133  coupled to a first turbine  132  and to the first compressor  131  of the first turbocharger  130 . Further, the method includes supplying (represented by block  330  in  FIG.  9   a   ) air from the first compressor  131  of the first turbocharger  130  to the air lubrication device  140 . 
     In particular, changing (represented by block  320  in  FIGS.  9   a ,  9   b  and  9   c   ) the speed of a first compressor  131  may include varying the speed of the first compressor  131 . For example, changing the speed of the first compressor  131  by using the transmission  133  can include increasing the speed of the first compressor  131  compared to the speed of the first turbine  132 . Additionally or alternatively, the changing the speed of the first compressor  131  by using the transmission  133  can include decreasing the speed of the first compressor  131  compared to the speed of the first turbine  132 . 
     With exemplary reference to  FIG.  9   b   , according to embodiments, which can be combined with other embodiments described herein, changing (represented by block  320  in  FIG.  9   b   ) the speed of the first compressor  131  comprises using (represented by block  321  in  FIG.  9   b   ) a second turbine  134  in parallel to the first turbine  132 . The first turbine  132  and the second turbine  134  are coupled to the first compressor  131  via the transmission  133 . 
     According to embodiments, which can be combined with other embodiments described herein, the method  300  further includes controlling (represented by block  335  in  FIG.  9   b   ) an amount of air provided to the air lubrication device  140  by controlling a rotational speed of the first turbocharger  130 . The rotational speed of the first turbocharger  130  can be controlled by controlling an exhaust gas flow provided to a third turbine  112  of a third turbocharger  110  being connected with an exhaust gas receiver  122  of the one or more engines  120 . The exhaust gas flow provided to the third turbine  112  of the third turbocharger  110  can be controlled by using (represented by block  336  in  FIG.  9   b   ) a flow controller  160 , as exemplarily shown in  FIGS.  7  and  8   . In particular, the flow controller  160  can be provided in a first bypass piping  13  bypassing the third turbine  112 , as exemplarily shown in  FIGS.  7  and  8   . Additionally or alternatively, controlling (represented by block  335  in  FIG.  9   b   ) the amount of air provided to the air lubrication device  140  can include controlling a rotational speed of the first turbocharger  130  by controlling an exhaust gas flow provided to the first turbine  132  by using (represented by block  337  in  FIG.  9   b   ) a bypass valve  170 , as exemplarily shown in  FIGS.  7  and  8   . In particular, the bypass valve  170  can be provided in a second bypass piping  14  bypassing the first turbine  132 . Additionally or alternatively, controlling (represented by block  335  in  FIG.  9   b   ) an amount of air provided to the air lubrication device  140  can include controlling a rotational speed of the first turbocharger  130  by using (represented by block  338  in  FIG.  9   b   ) a further flow controller  161  provided downstream of the first turbine  132  of the first turbocharger, as exemplarily described with reference to  FIG.  8   . 
     With exemplary reference to  FIG.  9   c   , according to embodiments, which can be combined with other embodiments described herein, the method  300  further includes driving (represented by block  340  in  FIG.  9   c   ) a second turbocharger  137  by using exhaust gas from the one or more engines. Additionally or alternatively, driving (represented by block  340  in  FIG.  9   c   ) the second turbocharger  137  can be conducted by using exhaust from the first turbine  132 . The second turbocharger  137  has a second compressor  135  coupled to a second turbine  134  via a further transmission  136 . The further transmission  136  is configured for changing a speed of the second compressor  135 . Additionally, the method  300  as exemplarily illustrated in  FIG.  9   c    includes changing (represented by block  350  in  FIG.  9   c   ) a speed of the second compressor  135  by using the further transmission  136 . Further, the method  300  includes supplying (represented by block  360  in  FIG.  9   c   ) air from the second compressor  135  of the second turbocharger  137  to the air lubrication device  140 . 
     Accordingly, in view of the above, it is to be understood that embodiments described herein beneficially provide for an improved air lubrication device for which the amount of air supplied to the air lubrication device can be controlled and adjusted. In particular, as described herein, compared to the state of the art, the effectivity of the air lubrication device can be improved by employing a transmission for increasing the speed of a compressor used for supplying air to the air lubrication device. Accordingly, an increased bubble generation under the vessel’s hull and thus a higher reduction of water-hull friction of the ship can be achieved, resulting in a reduction of the overall operation costs. Further, compared to the state of the art, embodiments as described herein have the advantage that residual energy of the turbine of the engine’s turbocharger can be employed for operating the air supply apparatus. As consequence thereof, compared to the state of the art, embodiments as described herein provide for an improved energy efficiency. Moreover, embodiments as described herein beneficially provide for the possibility to compensate the so-called mismatching between compressor and turbine, by utilizing a separate turbocharger with a transmission coupling the turbine with the compressor used for bubble generation for hull lubrication. 
     While the foregoing is directed to embodiments, other and further embodiments may be devised without departing from the basic scope, and the scope is determined by the claims that follow. 
     REFERENCE NUMBERS 
     
         
           1  exhaust gas provided from one or more engines 
           11  first exhaust gas pipe 
           12  second exhaust gas pipe 
           13  first bypass piping 
           14  second bypass piping 
           15  exhaust gas outlet piping 
           16  first air supply pipe 
           17  second air supply pipe 
           18  air intake 
           19  third air supply pipe 
           20  exhaust gas connection 
           100  air supply apparatus 
           110  third turbocharger 
           111  third compressor 
           112  third turbine 
           113  shaft 
           120  one or more engine(s) possibly comprising one or more turbocharger(s) 
           121  air receiver 
           122  exhaust gas receiver 
           130  first turbocharger 
           131  first compressor 
           132  first turbine 
           133  transmission 
           134  second turbine 
           135  second compressor 
           136  further transmission 
           137  second turbocharger 
           140  air lubrication device 
           150  charge air cooler 
           160  flow controller 
           161  further flow controller 
           170  bypass valve 
           200  ship 
           300  method of supplying air to an air lubrication device 
           310 ,  320 ,  321 ,  330 ,  335 ,  336 ,  337 ,  338 ,  340 ,  350 ,  360  bocks representing method steps of the method of supplying air to an air lubrication device described in the present disclosure