How can I power my LEGO pneumatic engine?
Since the compressor produces compressed air, it would certainly work, given you build adequate fittings and take precautions against overpressurization.

LEGO pneumatics have been tested to withstand as much as 8 bars or 120 psi, but you definitely should plan with safety margins. If your compressor can produce higher pressures, I'd suggest building in some kind of release or auto-shutoff valve to prevent damaging the LEGO parts.