Process flowsheeting is a way of drawing pictures or diagrams to show how an industrial process or operation works. For example, you can draw a picture showing how oil or gas is extracted from the ground and how it is transported to a refinery. Each step in the process is represented by an object such as a pump, valve or tank. Arrows show how the process flows from one step to the next. By looking at the picture you can see how the different parts of a process are connected.