US 7,739,767 B2 · Pigging system

Abstract

A liquid transport system has a number of access points, referred to generally as nodes, connected to an endless loop of piping such that liquid flowing in the system, to move the liquid from one node to another, flows in two generally discrete paths from a source node to a destination node. In general, any node can be associated with either a liquid source or a liquid destination. A source in a first liquid transfer can act as a destination in a subsequent liquid transfer, and vice versa. A single pigging system can be used to clean substantially the entirety of the liquid transport system among all sources and all destinations, except for leads from the nodes to the sources and/or destinations. The liquid transport system can be cleaned in place, thus to clean all of the piping which runs between the respective nodes in the liquid transport system.

Claims43

Dependent claims

A liquid transport system, comprising:

(a) a pipeline defining a closed loop fluid transfer path wherein a transfer fluid can be caused to flow, from a starting location, to a destination location;
(b) at least first and second transfer fluid source/destination nodes disposed along the fluid transfer path, a separate joining conduit joining each said transfer fluid source/destination node to a liquid source/destination;
(c) first and second pig launchers operatively connected to said fluid transfer path such that said first and second pig launchers are always in the fluid transfer path;
(d) at least one pig operative with said pig launchers and wherein said at least one pig can be moved along the fluid transfer path between said first and second pig launchers thereby to remove such transfer fluid from such fluid transfer path;
and
(e) one of said source/destination nodes being connectable to both a source/destination and to a non-product liquid supply, through a hook-up panel.

3 more elements

A liquid transport system, comprising:

(a) a closed loop pipeline defining an endless loop fluid transfer path-wherein a transfer fluid can be caused to flow, from a starting location, in a single direction through the closed loop pipeline along the fluid transfer path, back to the starting location;
(b) first and second pig launchers operatively connected to the fluid transfer path;
(c) at least first and second discrete transfer fluid source/destination nodes disposed along the fluid transfer path, including at least one said node which can function as a source node and at least one said node which can function as a destination node, each said transfer fluid source/destination node being associated with a corresponding joining conduit;
(d) first and second pigs operative with said pig launchers such that said first pig can be moved in a first direction along the fluid transfer path and said second pig can be moved in a second direction along the transfer path opposed to the direction in which said first pig has moved;
and
(e) flow control apparatus effective to stop movement of said first and second pigs on opposing sides of, and proximate, a common said joining conduit.

3 more elements

A liquid transport system, comprising:

(a) a closed loop pipeline, an endless loop fluid transfer path being defined in said closed loop pipeline, and wherein a transfer fluid can be caused to flow, from a starting location, in a single direction through the closed loop pipeline along the fluid transfer path, back to the starting location;
(b) first and second pig launchers operative to launch one or more pigs into said closed loop pipeline;
(c) at least a first pig in said closed loop pipeline;
(d) a plurality of transfer fluid source/destination nodes in said closed loop pipeline defining segments of the fluid transfer path between respective ones of said source/destination nodes;
(e) node control valves disposed at or adjacent said transfer fluid source/destination nodes, said node control valves being outside said closed loop pipeline such that transfer fluid flowing through said closed loop pipeline does not flow through said node control valves;
and
(f) no more than one of the fluid transfer segments having a segment control valve which can control flow of transfer fluid through the respective segment of the fluid transfer path, such that such transfer fluid can be caused to flow, from such starting location, in a single direction through said closed loop pipeline along the fluid transfer path, back to the starting location in said closed loop pipeline while traversing no more than one such valving-controlled segment of the fluid transfer path.

4 more elements

A liquid transport system, comprising:

(a) a closed loop pipeline defining an endless fluid transfer path wherein a product liquid can be caused to flow, from a starting location, in a single direction through the closed loop pipeline, back to the starting location;
(b) first and second pig launchers operatively connected to the fluid transfer path;
(c) first and second pigs in said closed loop pipeline;
and
(d) at least first and second transfer fluid source/destination nodes in said closed loop pipeline,
said fluid transfer path being configured so as to accommodate at least one of said first and second pigs being disposed in the fluid transfer path while product liquid is being transferred from a first one of said transfer fluid source/destination nodes, through one of said pig launchers, to a second one of said transfer fluid source/destination nodes, such that a liquid flow stream, flowing from the first one of said transfer fluid source/destination nodes, through the respective said first or second pig launcher, to the second one of said transfer fluid source/destination nodes, flows through the respective said first or second pig launcher and past the respective said first or second pig while the respective said pig is being retained in the respective said first or second pig launcher.

3 more elements

A method of transferring transfer fluid through a liquid handling system from a transfer fluid source, to a transfer fluid destination in a pipeline, the liquid handling system comprising first and second pig launchers operative to launch first and second pigs into the pipeline, the transfer fluid source and the transfer fluid destination having access to the pipeline through respective first and second nodes in the pipeline, the transfer fluid source being connected to the pipeline through a first such node, the transfer fluid destination being connected to the pipeline through a second such node, the method comprising:

(a) transferring transfer fluid from the transfer fluid source to the transfer fluid destination through the pipeline;
(b) terminating access from the transfer fluid source to the pipeline;
(c) launching the first pig from the first pig launcher toward the second node, and stopping the first pig proximate but not past the second node;
and
(d) launching the second pig toward the second node, and stopping the second pig proximate both the second node and the first pig.

2 more elements

A method of transferring liquid product through a liquid handling system from a liquid product source along a transfer path, through a closed loop pipeline, to a liquid product destination, the liquid handling system comprising first and second pig launchers, the liquid product source and the liquid product destination having access to the closed loop pipeline through respective first and second nodes, the liquid product source being connected to the closed loop pipeline through a first such node, the liquid product destination being connected to the closed loop pipeline through a second such node, the method comprising

transferring a specified quantity of liquid product from the liquid product source, into the closed loop pipeline at the first node, through the closed loop pipeline to the second node, and from the second node, out of the closed loop pipeline to the liquid product destination, including concurrent flow of the liquid product along at least first and second separate and distinct flow paths in the closed loop pipeline,
upon having transferred the specified quantity of the liquid product into the closed loop pipeline, terminating transfer of the liquid product into the closed loop pipeline,
subsequent to the termination of the transfer of such liquid product into the closed loop pipeline, and while the closed loop pipeline still contains a portion of such liquid product between the liquid product source and the liquid product destination, closing a flow control device and thus closing off flow of fluid at a location in the closed loop pipeline,
after closing off the flow of fluid at the location in the closed loop pipeline, introducing a compressed gas into the closed loop pipeline adjacent the flow control device and between the flow control device and one of the pig launchers, which pig launcher has therein a pig, the compressed gas moving product liquid in the closed loop pipeline toward and through the respective pig launcher, such that the product liquid is all ahead of the pig in the closed loop pipeline,
after the compressed gas has moved the product liquid through the pig launcher, launching the pig, and thus driving the product liquid ahead of the pig, in the closed loop pipeline,
after launching the pig into the closed loop pipeline, using the compressed gas to move the pig, and the product liquid ahead of the pig, through the closed loop pipeline to the second pig launcher,
after the pig has reached the second pig launcher, continuing to move the product liquid ahead of the compressed gas, past the pig launcher and out of the closed loop pipeline toward the product liquid destination,
after the product liquid leaves the closed loop pipeline, continuing to feed the compressed gas along the transfer path to the liquid product destination, thereby delivering, to the liquid product destination, substantially all of the liquid product which was in the closed loop pipeline when transfer of the liquid product into the closed loop pipeline was terminated.

5 more elements

Dependencies are inferred from the claim text.

Pigging system

Life of this patent

Pigging system

Life of this patent

Abstract

Claims43