How to build a conceptual data model of the subject area (distillation column)?

Question

PostgreSQL

Good afternoon. There is a subject area (distillation column), it is necessary to build a conceptual data model in PowerDesigner. There is an idea, but it seems to me that this is not quite what you need.
The conceptual model, as I understand it, is the connection between users of a given subject area.
Idea:
Consider by input-output - there are those people who supply material for the column (input), there are people who receive material from the column (output)
as output !