Effects of working fluids on cryogenic power generation through two stages organic Rankine cycle

The cold energy of LNG released during its regasification process can be used to generate power using a working fluid in the organic Rankine cycle (ORC). This study will investigate three working fluids, namely R1150, R170 and R290 to produce power in the two stages ORC cycle in the LNG regasification plant with a capacity of 50 MMSCFD based on simulation program. Based on the simulation program, the fluid pressure coming out of turbine 2 greatly influences the net power produced by the cycle. R290 has a working pressure range that is narrower than the other two refrigerants as it has the highest dew point temperature among the three. The mass of working fluid that can be utilized in the cycle is also shown by R290 as the difference between LNG and condensation temperatures are relatively much higher than the other 2 refrigerants. As a result, R290 will provide the highest net power, but can only be used at maximum working fluid pressure of 550 kPa, which provides net power of around 880 kW. If the desired net power is higher than 880 kW, the R170 shows better performance than R1150.