you dont need asprite. all tile just 16x16px.  that lava have 9 tile combine, ( top left/ top/ top right/left/midle/right/bottom left/bottom/bottom right ), just like other tile. you can make as big as you want.  if you want use to make game, just set grid size to 16 x 16. it already like example,  you can make as high as you want.
if you want it to go higher just increase left/middle/right tile

if you want make it wider

of course you need 12 frame to make it animation.  that why it call tile set.

here i put all flow lava as preview. you can download now