Feb 3 (Reuters) - Freeport LNG, the second-biggest U.S. liquefied natural gas (LNG) exporter, said on Friday it plans to restart one of three liquefaction trains at its long-idled Texas export plant this week.

Liquefaction trains turn natural gas into LNG for export.

In a filing with Texas environmental regulators, Freeport said it "anticipates the purge and restart of Liquefaction Train 3 will begin on Feb. 3 with Trains 2 and 1 following sequentially."

That will allow "time between startups for each train to stabilize and run for several days at nominal rates," Freeport said in the filing.

Freeport also said the "initial purging, restart, and cooldown of each train will result in venting to the Liquefaction Flare as the trains are brought to operating temperatures that allow for the cessation of flaring."

Federal regulators this week approved Freeport's plan to start sending gas to Train 3. On Thursday, Freeport asked regulators for permission to start loading LNG on ships to free up space in the storage tanks for the new LNG expected to be produced.

Federal regulators, meanwhile, will hold a public meeting on Feb. 11 to provide members of the community and other interested parties an opportunity to voice their concerns about Freeport's restart plans and get an update on what's happening at the plant, according to a filing by the Sierra Club, an environmental group.

Energy analysts expect it will take until mid-March or later for Freeport to return to full LNG production.

The Freeport plant shut after a fire in June 2022. The energy market expects gas prices to rise once the plant starts producing LNG again. When operating at full power, Freeport can turn about 2.1 billion cubic feet (bcf) of gas into LNG each day. That is about 2% of total U.S. daily gas production.

Despite the planned Freeport restart, however, U.S. gas futures fell about 3% to a 25-month low on Friday due to forecasts for milder weather in February.

The outage forced Freeport's big customers, including JERA and Osaka Gas, to book hundreds of millions of dollars of losses. Its other big buyers include BP , TotalEnergies and SK E&S. (Reporting by Scott DiSavino in New York and Arathy Somasekhar in Houston; Editing by Paul Simao)