Do you ever hear operators complaining about refinery fuel gas being too lean? Do your process engineers ever tell you that your furnaces are duty limited because the fuel gas valves are saturated?
I’m sure that every refinery engineer has seen an operator just dump more LPG into the fuel gas system at one point in time or another. You, yourself, may have even gotten comfortable with this lazy habit. If your refinery engages in this type of activity without fully scrutinizing the fuel gas content, you may be wasting millions of dollars each year out of plain stupidity.

Let’s first review some basic chemical properties of molecules – the table below compare heating content of various hydrocarbons.