59. LNG tank truck
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59. A tank truck arriving for filling had a tank pressure of 0.4 MPa, with no liquid inside. The filling procedure stipulates that filling is only allowed when the tank pressure is less than 0.1 MPa. Before and after this pressure relief operation, the mass of the tank truck decreased by at least ( ) Kg. (The temperature change is ignored in the calculations; the effective volume of the tank truck is 60 cubic meters, and the density of BOG is 0.9 Kg/m3.)
3*60*0.9=162
The above is only a rough estimate, based on PV=nRT, and it assumes that the temperature remains constant before and after, which is characteristic of an ideal gas； The reality is that the temperature changes after pressure reduction, and it isn’t an ideal gas; using software for simulation will yield more accurate results.