Just found additional info.

One site advocates Benco B-17 paint remover for powercoat removal.
Powder Coating: The Complete Guide: Stripping Powder Coat

Could you use CO2 (dry ice) to blast the powdercoat off? This site shows an examples of dry ice blasting on powdercoat:

Here is a dustless blaster using garnet. The dustless blaster uses water with the abrasive to cool the surface. The video addresses the problem squidpuppet identified. Seemed to work (pretty salesy, but informative):