Balances on Spreadsheets

Spreadsheets are adept at mass balances. The mass balance exercises in this chapter may be solved with spreadsheets. Indeed, most commercial software to model chemical processes are embellished spreadsheets. We offer here a tutorial in two examples a simple separation and a process with a recycle. The tutorial assumes a basic knowledge of spreadsheets, such as how to use a mouse to select a cell and how to copy and paste. 

Spreadsheet Example I The process below separates grain extract (50 kg/min, 97 wt% water and 3 wt% ethanol) into a product stream and a waste stream. The product stream must recover 99% of the ethanol in the grain extract. In addition, the product stream must be 50 wt% ethanol. 

Solution to Spreadsheet Example I A spreadsheet solution to this exercise is shown on the following page. The steps below will lead you through the process of creating this spreadsheet. The steps will refer to locations on the spreadsheet, known as cells, by their column (an uppercase letter) and their row (a number). 

Enter the title. Type Example 1 in cell Al. For those new to spreadsheets, first select cell Al with the mouse. This should highlight the border around the cell. Then type Example 1 and hit enter. 

Enter the list of process specifications. Type Process Specifications in cell A3. Do not be concerned that the text extends beyond cell A3. Because there is nothing in the adjacent cell, the text appears in full. Enter the other specification descriptions in cells A4 through A7, and enter their values in cells C4 through C7 as shown in the example. 

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