For the gas supply system used on LNG (liquefied natural gas) powered ships

propane and 50% aqueous solution of ethylene glycol are used as the intermediate heat exchange medium at the given low pressure condition. Choose the heat transfer correlation of spiral tubes and shell side heat transfer correlation for the heat exchanger. Then calculate the heat transfer area and the length of the coiled tubes of the spiral wound LNG heat exchanger (SWHE) with MATLAB programming software. Combined with engineering practice

the distribution of the tube length and heat transfer area when using two-stage heat exchangers are discussed. The HYSYS simulation results show that when the flow and the heat exchange state of the LNG in the pipe are the same

the mass flow rate of the required water glycol is 10 times that of the mass flow rate of propane. Due to the phase change of propane

the flow rate of gaseous propane on the shell-side of the heat exchanger that varies greatly

which can reach 1.7 m/s at the exit. So it requires the heat exchanger to have a higher resistance to pressure. The flow rate of water glycol in the shell side is only about 0.2 m/s. When it is divided into two-stage heat exchangers

the heat exchange area and the length of the tubes of the gasification stage are less than 12.7% of that of the heating stage. When the two stages are the same size

at least 80% of the heat exchange area is wasted. The selected heat exchanger is used on the LNG powered ship. Both space utilization and safety are required. After the calculation

it is believed that although propane changes phase

the heat transfer advantage is not obvious and the safety advantage is not as good as water glycol.