We are using BAW v19.x and want to restrict multiple sessions from the same user account. If the one user is logged in the process portal and another use logs in using the same account on a different PC, we want the 2nd user to have a different session after they login or restrict login.

Is there any configuration to restrict the multiple sessions for one user account in the process portal?

There is no such feature to restrict multiple sessions from same account. You could obtain the IP address from the where the user is connected (that feature was added in version 20.0.0.2) but certainly no feature to restrict multiple sessions.

BPM is designed to support multiple session per user and there are scenarios where this is required. You will need to use inbuilt WebSphere inbuilt security configurations or session management for such a scenario. Use the WebSphere command-line administration tool (wsadmin) AdminConfig commands to access and modify BAW security properties as configuration objects.