"in a separate session" is correct and can be used in written English.
You can use this phrase when referring to a specific event or encounter that is distinct from other events. For example, "We discussed the budget in a separate session."
All subjects also received application of 1.2 ml lemon juice in the mouth in a separate session (data to be reported separately).
In a separate session, the synod called on the government to launch an independent review of the impact of benefits sanctions after hearing anecdotal accounts of hardship and humiliation from bishops, clergy and lay members.
In a separate session at a Sydney media conference, News Corp's Chris Mitchell, the editor-in-chief of the Australian, took aim at Fairfax Media's style of journalism, its embrace of social media and its alleged leftwing attitude.
I've uploaded the slides on SlideShare and you can see them here: In a separate session, Graham gave an in-depth explanation of how we implemented the Content API over the last few months.
On July 16th, as part of the Lincoln Center Festival, there will be a "Merce Fair," a twelve-hour blowout of performances, films, talks, and also a class in which you, too (and your kids, in a separate session), can learn a Cunningham piece.
Khan's spokesman said he had never shared a platform with Siri but spoke in a separate session during a two-day conference about Guantánamo Bay and that, at the time, he was a partner in the human rights law firm Christian Khan and chaired Liberty, the human rights campaign group.
"We get to wear all these hats that in a production company different people on the team would wear," he said earlier in the day, during a separate session.
[F]FDG PET scans were visually rated at a separate session in an analogous manner (SJS) blinded to diagnosis and PIB-PET status.
In a first separate session, the participants were instructed about the nature and rules of the UG.
In order to screen for cognitive deficits below the age-associated norms, all older participants were administered a battery of standardized neuropsychological tests in a separate testing session within 2 months of the MRI scanning session.
In a separate learning session, region names appeared on a different map in their proper location, then moved to the margins of the map.
