With the installation of a single-phase expander, an increase in overall process efficiency of approximately 5% can be obtained. By installing a new EIC upward flow two-phase expander, this value can increase to as much as 8%. In LNG liquefaction trains, additional LNG output is achieved through the enthalpy reduction of the LNG during the expansion across the expander. The enthalpy reduction of the LNG reduces the boil-off losses and increases the LNG output for the same input. A typical expander with a 2000 kW generator installed in an LNG pressure reduction stream can provide as much as 120,000 tons of additional LNG per year!
In addition to the LNG capacity increase, these expanders provide the benefit of electrical power generation. A typical expander has a power generation potential of from 1.0 to 3.0 megawatts and with an expander efficiency of 88 percent, an output of 880 to 2640 kW can be realized. Over the course of a year, this can total more than approximately 23,000,000 kilowatt-hours, and at a cost of about $0.12 per kilowatt-hour, more than $2,800,000 of power is produced per year.
With these significant economic benefits realized, the potential payback time for investing in an Ebara Expander System can be less than 1 year and sometimes as short as a few months.