I used the effect new flames 01 custom but when i save it to any extension with a default background (black) the effect is much more beautiful and the way i want to stay and i used Gif Animator for mount the image sequence the way it is in the preview of the pi3:
but my purpose was to transparent background with the effect,
after searching for days i understood it is not possible to save a background working and effect with alpha, then save only the effect new flames with aplha and remove black from bg option enabled and applied using after effects with the first image but the result was that:
I think what you want to do is render just the particles with alpha to a PNG sequence, then in After Effects composite both layers together so you can end up with transparency from both layers. pI3 only saves transparency for the particles.
If you're asking something else, please ask again. :-)