A Process Flow Diagram (PFD) is a diagram which shows the relationships between the main components in a system. Process Flow Diagrams are widely used by engineers in chemical and process engineering, they allows to indicate the general flow of plant process streams and equipment, helps to design the petroleum refineries, petrochemical and chemical plants, natural gas processing plants, and Schematic flow diagram of a typical oil refinery . Saved from en Tools Chemical Engineering Electronic Engineering Process Control Control System Industrial Piping And Instrumentation Diagram Oil And Gas News Process Flow Chart. Oil And Gas News Energy Oils Petroleum Engineering Innovation Strategy Oil Industry Oil Rig Crude Oil Writing Process flow diagram is the drawing showing general flow of hydrocarbon material (gas/liquid) in the platform. Typical PFDs for wellhead and production platforms may be different. Typical PFDs for wellhead and production platforms may be different.