Qatargas using boil-off gas to unload LNG, starting in Japan
Qatargas, the world’s biggest LNG producer, said Monday it will use boil-off gas to power its chartered conventional LNG vessels, after a successful unloading in Japan.
The Al Jasra LNG vessel was used to start the boil-off program while discharging at the Niigata LNG Terminal in October 2019, Qatargas said. The program has the support of Japanese buyers, it added.
Prompted by IMO2020 rules that have placed severe limitations on the use of high-sulfur fuel oils, LNG vessel operators have looked to alternative methods to power their ships, including sulfur from the gas stream or a switch to very-low sulfur fuel oil, marine gasoil as well as LNG boil-off gas.
LNG tankers are designed to carry natural gas in liquid form at a temperature of minus 163 degrees C, which is close to the vaporization temperature. The natural evaporation, known as boil-off, is unavoidable and has to be removed from the tanks to maintain the cargo tank pressure.
Using the boil-off natural gas instead of conventional fuel oil reduces greenhouse gas and other harmful emissions over the course of the discharge operation, Qatargas said