Is there a way I can "compile" my perl code so that others can only run it, not read it?

Yes. Don't give them the code. Run the code on a server you control, and let the users run queries against it over the network.

That's not what you want to do? You need to let them run your code on their own hardware?

Ok, still possible. Do not grant redistributing/relicensing permissions for your code, either in part on completely (up to you).

That's not what you want do do? You wanted it to be concealed via technical measures?

Sorry, no can do.

As far as I'm concerned, that's a good thing. CPAN might never have happened otherwise.