What can we do to improve the process?
It has been determined that there are two viable ways to produce electricity during the LNG regasification process. The first one is the implantation of an Organic Rankine Cycle. The second one is the direct expansion of the natural gas.
Organic Rankine Cycle
A Rankine cycle is a thermodynamic model applied to heat engines in order to predict how much heat they can convert into mechanical work. The heat is supplied to a closed circuit where a fluid produce work going through a gas turbine. The only difference between a Rankine Cycle and its Organic version is the use of an organic fluid in the last one.
To produce electric power, the LNG is used as heat sink for the condenser in the Organic Rankine Cycle. Then, a pump increases the pressure of the working fluid and it becomes gas in a vaporizer. Finally, this gas is expanded in the turbine to produce mechanical work.
Direct Expansion of the Natural Gas
In this case, the first step is to increase significantly the LNG pressure. After its regasification, the natural gas is superheated by an external heat source and finally it is expanded in a turbine producing mechanical work.
The combination of both
Some studies have concluded that it is possible the combination of the two methods to extract the maximum energy. This system would be able to obtain the best performance of the process.