Pneumatic valves are generally used with compressed air from vacuum to 16bar.

They come in 2/2, 3/2, 5/2 and 5/3 functions depending on their requirements (3/2 = 3 port/2 position valve)

Process valves will be generally 2/2 valves used with media other than compressed air i.e., gases and oils.

They may be in different materials and are likely to be designed for challenging environments i.e., ATEX.