The great thing about using steam is you have perfect control over temperature. Steam from a tea kettle, that is not under pressure will always be at the same temperature. Water boils at 212 deg. F at sea level.
Steam is also dry. Only when it cools does it form water droplets.

If you only work on a small area at a time and never get the area so hot that you can't put your hand on it you should be OK. The only problem I can think of with acrylic felt is that it won't shape quite as well because it basically a plastic. So the temperature range at which it will soften and be able to be shaped is very narrow.

But, heck, I'm sure you have some scraps. Give it a go. Hands-on experience is the best teacher. Once you know something can be done then you only need to find out what works best for you.