Can I renew facebook token automatically?

I am working on collaborative web platform by ruby on rails and it's connected with facebook app (v2) by Koala gem..

When a user register by facebook account, there is facebook token (expire after 60 days)

The questions:

1- when and how renew the token in normal cases?

2- Can I renew token for 60 days again before end validity of the token?

3- Can I renew token automatically when user used his account in app with old session (without new sign in), or the user must sign out and sign in again to renew token?

I show this answer, but the tokens of users doesn't renew automatically when users visit to site with old sessions (without signin), do I have to finish their sessions automatically to force them to sign in again?