The SIAD Group’s engineering company SIAD Macchine Impianti (SIAD MI) is operating a re-liquefaction plant for the boil-off gas (BOG) located at a liquefied natural gas (LNG) storage facility owned by Depositi Italiani GNL – DIG (a joint effort between PIR group, Edison, and Enegas) at the Port of Ravenna, Italy.

The installation included four cryogenic compression packages (BOG compressors) designed for the recovery and re-liquefaction of evaporated natural gas.

Consisting of two atmospheric storage tanks, the new storage facility will see LNG transported by Edison to Ravenna via LNG carrier before being transferred and stored in the tanks. From there, the LNG can either be bunkered or loaded by tankers and distributed at filling stations. 

With the transport sector contributing heavily to harmful emissions, the new facility has the potential to increase the sector’s sustainability with its capacity to store 20,000m3, capable of refuelling up to 12,000 trucks and 48 ferries per year. 

During the various transfer operations (from the LNG tanker and during distribution), liquid methane partly vaporises and goes from a liquid to a gas, the BOG, which SIAD MI will compress and re-liquefy to be stored in the tanks. 

The company’s re-liquefaction plant will be able to treat 1.1 tonnes of methane per hour, for a total of about 26 tonnes per day of recondensed gas. By using the methane, it’s estimated that the plant could save 6m tonnes of CO2 in comparison to other fuels. 

Four BOG compressors were also installed by SIAD MI, two for re-liquefaction at the plant and two for the managing of the gas boil-off during LNG transfer operations from the carrier to storage. 

Design and construction of the plant was completed in 11 months and has been fuelled by carrier-delivered LNG from August 2021, with operations beginning in October.