Good idea.
Being lazy, I'd probably build something like that with the air line coming in from the side down low, and out the side up high with screw caps on top and bottom. Then Just unscrew the caps to replace the dessicant without having to disturb the piping. If you built it out of clear tubing, you could tell when the dessicant needed to be changed, also. I don't know if clear tubing is rated for compressed air though. Most recommendations are to avoid any type of plastic pipe for compressed air, although there are some that are specifically rated for it. There's a danger of rupture, and with all that stored energy that could be dangerous.
