Powered mobile liquefied gas carriers

Claim 3

A method as claimed in claim 1 in which the second part flow is additionally used for cooling the first part flow, which is to be returned, in a lower temperature range of the first part flow.

Claim 4

A method as claimed in claim 1 in which the whole of the gas produced by evaporation is divided into the two part flows at a ratio controlled by the re-liquefaction of the first part flow.

Claim 5

A mEthod as claimed in claim 1 in which the first part flow is compressed substantially adiabatically by utilising energy derived from the drive of the carrier.

Claim 6

A method as claimed in claim 1 in which the second part flow is compressed after having been heated by the first part flow.

Claim 7

A method as claimed in claim 1 in which the first and second part flows are conducted in countercurrent for the said transfer of heat.

Claim 8

A method as claimed in claim 1 in which the re-liquefied gas is subjected to final cooling.

Claim 9

A method as claimemd in claim 1 in which the entire collected gas is utilised for cooling the first part flow prior to division into two part flows.

Claim 10

A method as claimed in claim 3 in which cooling is performed with the entire collected gas in a low temperature range and the second part flow is utilised for cooling the first part flow conducted through the compressor and returned to the vessel in a temperature range above the low temperature range.

Claim 11

A method as claimed in claim 9 in which the second part flow is branched off from the collected gas at a temperature level which corresponds substantially to the temperature of condensation.

Claim 12

A method as claimed in claim 9 in which the entire gas flow is divided into the two part flows after passing through a final cooling zone and condensation zone for the first part flow.

Claim 13

A mobile liquefied gas carrier having means for utilising evaporated liquefied gas to drive the carrier, an insulated vessel to contain liquefied gas, a gas delivery duct leading from the vessel and dividing into branch ducts, the first branch duct leading through a compressor, one side of a heat exchanger means and an expansion element and back to the insulating vessel, and the second branch duct leading through the other side of the heat exchanger means to the drive means.

Claim 14

A mobile liquefied gas carrier having means for utilising evaporated liquefied gas to drive the carrier, an insulated vessel to contain liquefied gas, a gas delivery duct leading from the vessel and dividing into branch ducts, the first branch duct leading through a compressor, one side of a heat exchanger means and an expansion element and back to the insulating vessel, and the second branch duct leading through the other side of the heat exchanger means to the drive means.

Claim 15

A gas carrier as claimed in claim 12 in which the heat exchanger means includes a condenser for the flow in the first branch duct and a condensate receiver through both of which the gas delivery duct passes.

Claim 16

A gas carrier as claimed in claim 12 in which the heat exchanger means comprises an inlet cooler, a condenser and an outlet cooler which are connected in series in the first branch duct and are combined into one structural unit.

Claim 17

A gas carrier as claimed in claim 12 in which the heat exchanger means includes a condenser for the flow in the first branch duct and a condensate receiver through both of which the second duct passes.

Claim 18

A gas carrier as claimed in claim 15 in which the second branch duct extends from the heat exchange means via a compressor to the drive means.

Claim 21

A mobile liquid gas carrier having a propulsion apparatus for driving the carrier, at least one vessel for containing liquified natural gas, a gas delivery duct communicating with said vessel to collect evaporated gas from said vessel, a re-liquifying device connected to said duct to receive the evaporated gas for re-liquifying a part flow of the evaporated gas, a first duct extending from said device to said vessel to return the part flow of re-liquified gas from said device to said vessel, and a second duct extending from said device to said propulsion apparatus to deliver a second part flow of evaporated gas from said device to said pRopulsion apparatus for combustion therein.

Claim 22

A mobile liquid gas carrier having a propulsion apparatus for driving the carrier, at least one vessel for containing liquified natural gas, a gas delivery duct communicating with said vessel to collect evaporated gas from said vessel, a re-liquifying device connected to said duct to receive the evaporated gas for re-liquifying a part flow of the evaporated gas, a first duct extending from said device to said vessel to return the part flow of re-liquified gas from said device to said vessel, and a second duct extending from said device to said propulsion apparatus to deliver a second part flow of evaporated gas from said device to said pRopulsion apparatus for combustion therein.

Claim 23

A mobile liquid gas carrier as set forth in claim 18 wherein said re-liquifying device includes a controllable three-way valve connected to said gas delivery duct; a heat exchanger unit having an outlet cooler, condenser and inlet cooler; a first cooling duct in said outlet cooler connected to said valve to receive the evaporated gas; a second cooling duct in said condenser connected to said first cooling duct to receive the evaporated gas therefrom; a second three-way valve connected to said second cooling duct; a third cooling duct in said inlet cooler connected to said second valve to receive a part flow of evaporated gas therefrom; and a compressor connected to said second valve to receive and compress a second part flow of the evaporated gas therefrom, said compressor being connected to said heat exchanger unit to deliver the compressed second part flow thereto for counterflow over said cooling ducts.

Claim 24

A mobile liquid gas carrier as set forth in claim 18 wherein said re-liquifying device includes a controllable three-way valve connected to said gas delivery duct, a compressor connected to said valve to receive and compress a first part flow of the evaporated gas, a heat exchange means connected to said compressor to receive the compressed first part flow from said compressor, said heat exchange means being connected to said valve to receive a second part flow of the evaporated gas for flow therethrough in countercurrent to the compressed first part flow to cool and re-liquify the compressed first part flow.

Claim 25

A mobile liquid gas carrier as set forth in claim 20 wherein said device further includes a second compressor connected to said heat exchange means to receive and compress the second part flow and wherein said first duct connects to said heat exchange means to receive the cooled first part flow and said second duct connects to said second compressor to receive the heated second part flow.