# An intro to flowcharts or "How on earth do we actually do all of that?"

Things ChEs do to processes:

• design
• troubleshoot
• analyze
• optimize
• etc., etc.

This course -> general guidelines or recipes. These help you to organize and tackle each unique problem.

Simplest (but at the same time most important) tool: flow diagram, flowsheet, or flowchart.

DEFINITION:

A flowchart is a diagram that completely represents a process (i.e., it includes the process units, process streams, etc.).

### So what are process units or streams?

Let's consider our bakery example first...

EXAMPLE:

You know that, in its simplest form, your friend's bakery must consist of two steps: a mixing step, and a cooking step. You might represent these two steps like this:

We are now on our way to out first flowchart!

Each of the steps can be thought of as a process unit (as you may have guessed).

Leaving only process streams:

DEFINITION:

A process stream is a line which represents the movement of material to/from process units. Typically these streams are labeled with information regarding the amounts, compositions, temperatures, pressures, etc. of the components.

So if we now add process streams to our diagram from above we will have a valid flowchart:

EXAMPLE
(cont.):

Before moving on we should mention a few additional things about our flowchart:

• The streams are labeled in a variety of differing units (cups, gallons, lbs, etc.). We will have to be careful of this as we move on in our analysis (more on this in the next section).
• I thought that we were "scaling-up" this process...why are the quantities still so small?
• Some of the streams have "unknown" quantities listed. These are labeled with variables (x and y) in anticipation of solving for these values (again, we will get to this aspect later).
• Finally, there are funny pictures inside the boxes. What do they mean?

OUTCOME:

Describe the characteristics and purpose of a flowchart.

TEST YOURSELF!

Choose the right flowchart!