Patent ID: 8490564

Claim:
A method for processing a dry gas into a liquefied natural gas and offloading the liquefied natural gas to a transport vessel with storage tanks, wherein the method comprises: a. mooring a floating liquefaction vessel to a seabed with a plurality of mooring lines extending below a sea level; b. using a connecting device connected to the floating liquefaction vessel to: (i) attach the transport vessel to the floating liquefaction vessel, wherein the connecting device has a telescoping walkway comprising an inner walkway slidably engaged within an outer walkway; and (ii) hold the transport vessel apart from the floating liquefaction vessel at a nominal distance, wherein the inner walkway extends and retracts from the outer walkway to accommodate wave action, wind effects, vessel dynamics, pitch, yaw, roll, surge, sway, and heave producing forces on the transport vessel and the floating liquefaction vessel; c. receiving the dry gas from a pretreatment source onto the floating liquefaction vessel; d. cooling the received dry gas to a cryogenic temperature using a heat exchanger connected to a liquefaction train, forming the liquefied natural gas; e. transferring the liquefied natural gas from the floating liquefaction vessel to the transport vessel using an offload flexible conduit in communication with a walkway offload flexible conduit on the telescoping walkway; f. transferring personnel and equipment within an enclosed walkway formed in the telescoping walkway between the floating liquefaction vessel and the transport vessel; g. returning hydrocarbon vapor from the transport vessel to the floating liquefaction vessel using a walkway vapor return flexible conduit connected to the telescoping walkway and in communication with a vapor return flexible conduit on the floating liquefaction vessel, wherein the hydrocarbon vapor is formed during offloading of the liquefied natural gas from the floating liquefaction vessel to the transport vessel; h. using a transport vessel controller of the transport vessel to continuously monitor a member of the group consisting of: receipt of the liquefied natural gas, storage of the liquefied natural gas in the storage tanks, offloading of the liquefied natural gas from the storage tanks, and combination thereof; and i. dynamically positioning the transport vessel in proximity to the floating liquefaction vessel using computer instructions in the transport vessel controller and a member of the group consisting of: (i) motions measured by a motion sensor on the connecting device or the transport vessel; (ii) a fan beam laser-based positioning system on the connecting device or the transport vessel; (iii) a dynamic global positioning system on the transport vessel; and (iv) combinations thereof.