ECH 1Y Lecture Notes - Lecture 18: Volatile Organic Compound, Control Volume, Unit Operation
20 Dec 2018
School
Department
Course
Professor
Document Summary
Cool air in -> heater -> hot air. Chaff, h20, c02, vocs (volatile organic compounds ) A unit operation is any step where a chemical or physical change takes place. Applies to many quantities: mass, energy, number of molecules. In-out+ generation = accumulation (mass/time) - (mass/time) + (mass/time) = (mass/time) Mass is neither created nor destroyed (with rare exceptions ) Control volume - box around unit operation. Mass water in = mass water out. 1 known stream of water that we feed into our control volume. Steam, water with spent grounds, & water in the coffee. Mfeed = mbrew + mspent + mevap. Assumption #1 - the amount of steam is negligibly small. Assumption #2 - the brew is mostly water. Coffee is about 99% water & 1% dissolved solids. Paper towels absorb water, but only a finite amount. The more paper towels you use, the more water you absorb.
