The Open Source Linux/Unix version of Redis (discussed on this list) can certainly run more than one redis-server process on the same machine. This usually requires each process use a different config file that declares a different TCP port and different folder for logfiles/snapshot files from the other processes.
I believe the Windows port can also run more than one redis-server process on the same machine, but I don't know Windows, so I don't know for sure.
Regarding the TTL property, what do you mean? Are you sending the commands described in the documentation page
https://redis.io/commands/ttl and not seeing the same results as the examples? What exactly are you doing?