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Determination of the ballast water exchange sequence for an LNG carrier using a liquid cargo handling Simulator

Fig. 2. Visualisation of the ballast installation of an LNG-in carrier (membranę cargo tanks) (7|

Rys. 2. Wizualizacja schematu instalacji balastowej gazowca „LNG-m” (sfeiyczne zbiorniki ładunkowe) [7]

•    eight starboard tanks: BS1S - 2055 m\ BD2S -3594 m\ BS4S - 2379 m\ BD5S - 4238 m³, BS7S - 2706 m\ BD8S - 4262 m³, BS10S -2462 m³, BD11S - 2108 m³;

•    three central tanks: BC3 - 1500 m³, BC6 -1500 m\ BC9- 1500 m³;

•    two forepeak tanks: BFP - 7782 m³, BFT -1500 nr (void space);

•    afterpeak tank: BAP - 3110 m³;

•    throttling valves for communication between ballast tanks and ballast lines, as shown in figurę 1;

•    centrifugal BP pumps; the pumps have identical characteristics and provide charging pressure of ~2.8 bar at a flow of -2,800 m³/h);

•    three sea chests Bchl, Bch2 with strainers;

•    throttling valves on the charging linę of each pump: Bvl, Bv2,Bv3;

•    cut-off valves: BV4... BV19;

•    non-retum valve Bv20.

The LNG-m ballast installation consists of:

•    four portsidc tanks: B1P - 4751 m³, B2P -6182 nr³, B3P - 6233 m\ B4P - 5518 nr;

•    four starboard tanks: BIS - 4751 m³, B2S -6182 nr³, B3S - 6233 nr, B4S - 5518 nr:

•    two forepeak tanks: BD - 1167 m³, BFT -1780 m³ (void space).

•    ballast tanks communicate with ballast lines via throttling valves:- throttling valves for filling tanks: Bv...P, Bv...S and Bv...C, Bv6. Bv9, Bv22,Bv23, Bv24.

•    centrifugal pumps BP.... ; the pumps have identical characteristics and provide charging pressure of ~2.8 bar at a flow of ~2,800 m³/h);

•    two sea chests Bchl. Bch2 with strainers;

•    throttling valves on the charging linę of each pump: Bvl,Bv2;

•    cut-offvalves: BV4... BV19;

•    non-retum valve Bv20.

The devices are separately controlled by point-ing at the image of the device and double clicking the left key of the mouse. This activates an extra window that allows to set working parameters of the device - a pump or valve. Similarly, informa-tion may be obtained on a ballast tank - e.g. the current volume of ballast water, percent of tank filling, level of filling etc. The operating indicators of the ballast installation show:

-    operation of ballast pumps,

-    cut-off valves open,

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Zeszyty Naukowe 25(97)