Image 1. Spar coming from the dryer is stored in one of the two silos before transfer to the hydrofluoric acid unit. This is the point where the company needed an accurate inventory measurement. All graphics courtesy of Chemours/Emerson In chemical manufacturing environments, feedstocks going into the processes are often liquids. Process designers prefer it that way because they understand the characteristics of liquids, how they behave under a variety of conditions and how they can be quantified.