While the user fills out the form during registration, the session becomes obsolete

Hello. Users get this problem during registration:
1) user start to register and try to fill all fields, type text about himself so it takes 20+ minutes
2) on next registration step session is closed so page is refreshed and all text is lose.
Result: user have to repeat.

Is it possible to make session infinite (or 1+ hour) during registration process only?
Thanks.