Abstract:
The present invention provides a system and a method for loading/unloading cryogenic or hot fluids between a free end of a transfer pipeline and a ship. The system comprises a shaft extended upwards to above the sea level, at least one dolly for the transfer pipeline at the free end, an internal hose, and a loading arm for connection with a ship manifold. The loading arm further comprises an external hose as well as an elbow spool, a valve, an end flange at its mobile end for connecting with a ship manifold. A crane is used to lift the mobile end of loading arms between a loading position and storing position. Internal and external hoses are freely hanging catenary for accommodating end displacements of a transfer pipeline and ship motions, respectively.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority of U.S. Provisional patent application Ser. No. 61/578,225 filed on Dec. 20, 2011. 
         [0002]    U.S. Patent Documents 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
               
             
             
               
                 3,379,027 
                 April 1968  
                 Mowell 
                  62/53 
               
               
                 3,434,491 
                 March 1969 
                 Bily 
                 137/315 
               
               
                 4,417,603 
                 November 1983  
                 Argy 
                 138/149 
               
               
                 6,886,611 
                 May 2005  
                 Dupont and Paquet 
                 141/279 
               
               
                 7,147,021 
                 December 2006  
                 Dupont and Paquet 
                 141/382 
               
               
                 7,147,022 
                 December 2006  
                 Devehat 
                 141/387 
               
               
                 7,299,835 
                 November 2007 
                 Dupont et al 
                 141/382 
               
               
                 7,438,617 
                 October 2008 
                 Poldervaart et al 
                 441/5 
               
               
                 7,836,840 
                 November 2010 
                 Ehrhardt et al 
                 114/230 
               
               
                 7,857,001 
                 December 2010 
                 Kristensen 
                 137/615 
               
               
                 8,176,938 
                 May 2012 
                 Queau and Maurel 
                 137/615 
               
               
                 8,181,662 
                 May 2012 
                 Pollack et al 
                 137/15 
               
               
                 8,286,678 
                 October 2012 
                 Adkins et al 
                 141/387 
               
               
                 2010/0287957 
                 November 2010 
                 Liu 
               
               
                   
               
             
          
         
       
     
         [0003]    Foreign Patent Documents 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 EP  
                 1,462,358 
                 May 2006 
                 B63B 27/30 
                 F17C 6/00 
               
               
                   
                   
               
             
          
         
       
     
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0004]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of Invention 
         [0006]    The present invention relates generally to loading/unloading cryogenic or hot fluids between a ship and onshore storage tanks Specifically, the present invention provides a loading system that extends from a free end of a transfer pipeline to a ship manifold. 
         [0007]    2. Description of the Related Art 
         [0008]    Typical LNG terminals have storage tanks onshore and a transfer system extending from the storage tanks to a loading/unloading platform where a ship is docked. The loading platform is located on a coast, a river bank, or offshore. At most terminals the transfer pipelines are supported on trestles (i.e., above the sea level), and terminate at a loading header on a loading platform. Articulated loading arms extend from the loading header to a ship manifold for fluid transfer. 
         [0009]    In these conventional systems, the transfer pipelines are fixed at the platform with expansion loops or bellows to accommodate temperature changes, and articulated loading arms accommodate ship motions. These conventional hard arms are made of rigid pipe and swivel joints. They are mounted on a supporting structure/ frame with balancing weight to extend arms toward a ship manifold as disclosed in U.S. Pat. No. 3,434,491 to Bily. 
         [0010]    Some improvements have been developed for the hard arms. For example, U.S. Pat. No. 7,857,001 to Kristensen et al discloses a loading system with a spiral and rigid pipe attached to a boom with trolleys to compensate longitudinal movements. U.S. Pat. No. 8,176,938 to Queau and Maurel discloses a loading system with a movable supporting frame that allows end displacements of a transfer pipeline. U.S. Pat. No. 8,181,662 to Pollack et al discloses a loading system with a supporting metal shaft pivotable at its base. Regardless of these improvements, all the systems above have the followings in common: rigid pipes and a number of swivel joints, and a large supporting structure. These arms are not only costly, but also require maintenance with leakage potential from the swivel joints. 
         [0011]    At a few terminals where LNG transfer pipelines are inside an underground tunnel, a vertical shaft is used at a loading station near the ship to host a rigid riser and support a loading header on the top. The rigid riser extends from the transfer line below to the loading header above. The same hard arms discussed above are then fluidly connected to the loading header. US2010/0287957 to Liu discloses a similar transfer system with a vertical shaft and a rigid riser inside. The difference is that the Liu&#39;s system allows end displacement of a transfer pipeline. However, stresses could develop at rigid riser ends under thermal expansion/contraction of the subsea transfer pipeline. 
         [0012]    Flexible hoses for cryogenic fluids have been developed. These cryogenic hoses typically consist of multiple layers of polyester fabric and polymeric film as well as inner and outer spiral wound stainless steel wires as disclosed in U.S. Pat. No. 4,417,603 to Argy. Flexible hoses have been disclosed as loading arms for example in U.S. Pat. No. 8,286,678 to Adkins et al, and used for ship to ship transfer of cryogenic fluids by Excelerate Energy. 
         [0013]    For ship-to-shore transfer, several systems have been proposed using flexible hoses. U.S. Pat. No. 6,886,611 to Dupont and Paquet discloses a loading system between a LNG ship and a termination point of a transfer pipeline that is fixed on a gantry above a main platform. The loading system comprises flexible loading arm(s) with one end permanently hung at the termination point and a free end hung under another gantry with a winch and cable near a LNG ship. During a loading operation, a connection module is lifted over with a crane and tied in with a ship manifold (first connection). The free end of the flexible arm is then pulled over with another winch and cable, and fluidly connected with the connection module (second connection). This system avoids swivel joints, and provides a mean to break a free fall of the flexible arm in case of emergency. However, the system cannot accommodate end displacements of a transfer pipeline. Moreover, the system doubles the number of flange connection/disconnection for each loading arm that is time-consuming. 
         [0014]    U.S. Pat. No. 7,299,835 to Dupont et al discloses a flexible loading system comprising flexible hoses with one end hung at a reel attached to a station and another end extended to a ship manifold. The flexible hoses can be stored by rotating the reel after loading operations. Again, swivel joints are needed at the reel axis or at the rotatable connection. 
         [0015]    A single point mooring system has also been proposed for subsea LNG transfer. The system comprises a cryogenic riser connecting subsea pipelines and a turret or the like, and loading arm(s) extended from the turret to a LNG ship. For example, U.S. Pat. No. 7,438,617 to Poldervaart et al discloses a system comprising a floating buoy, turntable reel as well as rotatable connection between flexible hoses and transfer risers. U.S. Pat. No. 7,836,840 to Ehrhardt et al discloses a system comprising a floating buoy, a flexible riser and a flexible arm with a submersible turret (i.e., rotatable) connection between the flexible arm end and socket at the ship bottom. 
         [0016]    Other systems have a vertical post anchored at the seabed. U.S. Pat. No. 3,379,027 to Mowell discloses a fixed tower, a rigid riser, a rigid loading arm partially submerged in water. U.S. Pat. No. 7,147,021 to Dupont and Paquet discloses a system that has a riser attached to a vertical post with a rotatable connection, and piping along the boom that extends from the riser to a LNG ship. EP 1462358 to De Baan uses a vertical post as a riser, and flexible arms extend from the riser top to a ship for fluid transfer. 
         [0017]    The drawback of these systems is the need for rotatable connection at an end of a loading arm as well as the difficulty to access underwater components. 
         [0018]    In summary, there is a need to develop a loading system that not only allows end displacements of a transfer pipeline, but also overcomes the drawbacks discussed above. 
       BRIEF SUMMARY OF THE INVENTION 
       [0019]    The present invention provides a loading/unloading system for cryogenic or hot fluids between a free end of a transfer pipeline and a ship. The system comprises a shaft extended from the seabed/river bed to above the sea level, at least one dolly for the transfer pipeline to expand/contract axially at the free end inside the shaft, an internal hose to accommodate end displacements of the transfer pipeline, a loading arm that further comprises an external hose to accommodate ship motions as well as an elbow spool, a valve, an end flange at its mobile end for connecting with a ship manifold, a hose hanger that fluidly connects two hoses in the middle, and a storing seat above the sea level and away from the ship. A crane is used to lift the mobile end of the loading arm between a loading position connected with the ship manifold and a storing position on the storing seat. 
         [0020]    Accordingly, it is a principal object of the invention to provide a flexible but robust loading/unloading system that can accommodate both the ship motions and thermal expansion/contraction of a transfer pipeline. 
         [0021]    It is another object of the invention to provide a loading system that is applicable for both cryogenic fluids and hot fluids with pipe end displacements to release thermal stresses. 
         [0022]    It is another object of the invention to protect a loading system from environmental impacts (e.g., corrosive sea-water, ocean wave, wind, and sunlight). 
         [0023]    It is another object of the invention to provide easy access for equipment that is below the sea level around a loading platform. It is another object of the invention to provide a loading system applicable for a ship docked at a water front or offshore. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The loading system, method and advantages of the present invention will be better understood by referring to the drawings, in which: 
           [0025]      FIG. 1  is a perspective view of a first embodiment of the system along with other components at a loading /unloading terminal; 
           [0026]      FIG. 2  is a perspective view of the first embodiment; 
           [0027]      FIG. 3  is an elevation view of a second embodiment of the system in a loading position; 
           [0028]      FIG. 4  is an enlarged view taken along  4 - 4  line in  FIG. 3 ; 
           [0029]      FIG. 5  is a sectional view taken along  5 - 5  line in  FIG. 4 ; 
           [0030]      FIG. 6  is a sectional view taken along  6 - 6  line in  FIG. 4 ; 
           [0031]      FIG. 7  is an elevation view of a third embodiment of the system in a stored position; 
           [0032]      FIG. 8  is an enlarged view taken along  8 - 8  line in  FIG. 7 ; 
           [0033]      FIG. 9  is an enlarged view taken along  9 - 9  line in  FIG. 7 ; 
           [0034]      FIG. 10  is an elevation view of a convex saddle and motor; 
           [0035]      FIG. 11  is an elevation view of a fourth embodiment of present invention; 
           [0036]      FIG. 12  is a perspective view of a surge drum and flexible connection with a transfer pipeline and a vapor return line; 
           [0037]      FIG. 13  is an elevation view of flexible connection between two transfer pipelines; 
           [0038]      FIGS. 14A to 14D  are simplified configurations at the free end of a transfer pipeline; 
           [0039]      FIG. 15  is a variation of the mobile end of the loading arms according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0040]      FIG. 1  is an overview of a first embodiment of the present invention in a loading or unloading (i.e., receiving) terminal. A ship  12  is docked at a dolphin  13 , and a shaft  15  is located around a coast line  16 . A transfer pipeline  17  extends from onshore tanks  14  to the shaft  15  with an anchor at a vault  11 , and is encased with an underground reinforced concrete conduit  18 . A crane  19  is located at the top of the shaft  15 . 
         [0041]      FIG. 2  shows a perspective view of this embodiment. A transfer pipeline  17  enters the shaft  15  with a dolly  20  and a vertical bar  29  to support its free end. A rigid n-shaped coupler  21  is supported on a beam  22  inside shaft  15  with two openings facing down and a valve  23  in the middle. A flexible hose  24  is fluidly connected with transfer pipeline  17  at the low end and freely hung from the n-shaped coupler  21  at the high end. A flexible arm  25  is fluidly connected with the n-shaped coupler  21  at one end, and lifted at a mobile end  26  with a chain  27  of a crane (refer to  19  in  FIG. 1 ). A convex saddle  28  is anchored to a wall of the shaft  15  providing a convex surface for the flexible arm  25 . In this embodiment, the flexible hose  24  and flexible arm  25  are freely hung in two planes perpendicular to each other. 
         [0042]      FIG. 3  shows a second embodiment while the flexible hose  24  and flexible arm  25  are freely hung in two planes parallel to each other. The transfer pipeline  17  enters the shaft  15  at an entrance  31 . The flexible hose  24  is fluidly connected with the transfer pipeline  17  at the low end and freely hung from the n-shaped coupler  21  at the high end. The flexible arm  25  comprises an internal hose  39  and external hose  40  extending from the n-shaped coupler  21  to a ship manifold  32  on a ship platform  33 . Both a dolphin  34  and shaft  15  are anchored to a seabed  35 , and extends upwards to above the sea level  36 . Between the internal hose  39  and external hose  40 , there is a stop flange  37  that is not allowed to pass through a restraint  38  so that the internal hose  39  is not bent excessively. In addition, the flexible hose  24  and flexible arm  25  can be freely hung in two planes with an intersectional angle varying from 0 to 90 degree to fit a site condition. 
         [0043]      FIG. 4  shows details for connection at a ship manifold during loading operations. The ship manifold  32  is supported on the ship platform  33  with a stand  41 . The mobile end  26  of the flexible arm  25  sits on the manifold platform  33  with a main leg  42  and an assistant leg  43 . The mobile end  26  comprises a powered emergency release coupler (PERC)  44 , an elbow spool  45  (i.e., a bend in this case), a valve  46 , and an end flange  47 . The mobile end  26  is fluidly connected with the ship manifold  32  at one end and with an external hose  40  at the other end below. At the elbow spool  45 , there is a handle  48 . Alternatively, a two-way splitter can be fluidly connected with the elbow spool  45  and a smaller-size hose can be fluidly connected with each way of the two-way splitter (e.g., two 10-inch size hoses can replace a 16-in hose for a 16-in size manifold flange). Using a smaller size of hoses can reduce the size of the convex saddle  28  and shaft  15 . 
         [0044]      FIG. 5  shows a cross-section view from line  5 - 5  in  FIG. 4 . The assistant leg  43  has a bottom plate  51 , a column  52 , and a top plate  53 . A roller  54  is supported with springs  55  at both ends. A pipe  56  sits on the roller  54  and two alignment guides  57  extend upward with a widen opening. At the bottom, a male bar  58  is inserted into a hole  59  in the manifold platform  33 . 
         [0045]      FIG. 6  shows a cross-section view of the main leg  42  along line  6 - 6  in  FIG. 4 . the pipe  56  sits on a concave saddle  61 . Alternatively, the main leg  42  has a combination of a roller ( 54  in  FIG. 5  ) and concave saddle ( 61  in  FIG. 6 ) sharing weight of the pipe  56  above. The height of both legs can be made adjustable with means such as leveling pins, rotating a threaded column, hydraulic jacking, etc. Those means are not shown for simplicity. 
         [0046]      FIG. 7  shows an elevation view of a third embodiment with the flexible arm  25  in a stored position. A transfer pipeline  71  enters a shaft  72  near the top. The flexible arm  25  comprises an internal hose  73  and external hose  74  freely hung from the transfer pipeline  71  at one end and from a convex saddle  75  at the mobile end. Both internal and external hoses are stored inside the shaft  72 , and protected from sea-water, wind and sunlight. 
         [0047]      FIG. 8  shows details around hanging off point with the transfer pipeline  71 . The transfer pipeline  71  is clamped with a clamp  81  that is tied to a dolly  89  with a vertical bar  82  and a nut  85 . The dolly  89  has at least two wheels  83  rolling along a metal track  84  (for example a box beam). Below the transfer pipeline  71 , there are a branch  86 , a valve  87 , a flange connection  88  and an internal hose  73 . 
         [0048]      FIG. 9  shows details taken along line  9 - 9  in  FIG. 7 . The mobile end  26  sits on a storing seat that comprises a side bar  91  and a top roller bar  92  of the convex saddle  75 . The convex saddle  75  is anchored to a shaft wall  93  at a bottom plate  97  along with a bracing strut  94 . An external hose  95  goes through a hole on a roof  96  of the shaft. The mobile end  26  has an end flange  98  and a quick connecting/disconnecting (QC/DC) device  99 . 
         [0049]      FIG. 10  shows details of a convex saddle  101  which comprises two semicircle guides  103 , and seven roller bars  104  in-between (refer also to  28  in  FIG. 2 ). In this variation, a round belt  105  is wrapped around the roller bars  104 , and driven by a motor  106  that is attached to a bottom roller bar and anchored to a base plate  102 . 
         [0050]      FIG. 11  shows a fourth embodiment of this invention intended for docking and loading two ships simultaneously. For simplicity,  FIG. 11  shows both loading arms at a stored position on a storing seat  117 . In this case, a shaft  113  is located offshore and a transfer pipeline  111  extends from onshore (not shown) to the shaft  113  around the seabed  35 . A n-shaped coupler  112  is hung on a wall of the shaft  113 . An internal hose  114  extends from the transfer pipeline  111  to the n-shaped coupler  112 . Outside the shaft  113 , an external hose  115  is freely hung from the n-shaped coupler  112  at one end with a mobile end  116  on the storing seat  117 . The storing seat  117  has two concave saddles at a distance 1.5 to 3 m apart on the top, and is mounted on piers of a dolphin  118 . A strap can be used to secure the mobile end in the seat (not shown). Alternatively, the storing seat  117  can share piers with a passageway, or be anchored directly into the seabed. Crane  119  is located at the top of the shaft  113 . 
         [0051]      FIG. 12  shows a surge drum  121  anchored to a wall  122  of a shaft  123 . A gooseneck spool  124  is fluidly connected to the top of the drum  121 . A vapor hose  125  extends from the gooseneck spool  124  to a vapor return line  127 . A fluid hose  126  extends from the bottom of drum  121  to a transfer line  128 . The drum  121  regulates any pressure surge. 
         [0052]      FIG. 13  shows flexible connection between two transfer pipelines. Inside a shaft  131 , a first transfer pipeline  132  and second transfer pipeline  133  are fluidly connected with two flexible hoses  134  and a u-shaped coupler  135  at the bottom. Both the flexible hoses  134  and u-shaped coupler  135  are in a freely hanging position. 
         [0053]      FIGS. 14A to 14D  show variations for the free end of a transfer pipeline  141 . There are a dolly  142 , branches  143  and at least one valve  144 . 
         [0054]      FIG. 15  shows a variation on the mobile end  26  of the loading arms. A presentation flange of a ship manifold  151  is facing up near the edge of a manifold platform  152 . With an elbow spool  153  (i.e., gooseneck spool in this case), an end flange  154  is facing down.