Students and faculty from Brigham Young University developed and delivered a small-scale process to Tonga for making biodiesel fuel from coconut oil. The central component of the process was the reactor where the coconut oil (triglycerides containing a variety of fatty acids - represented as R₁, R₂, and R₃) is reacted with methanol in the presence of sodium hydroxide (acting as a catalyst, thus not consumed) as shown in the following reaction:

The conversion of coconut oil is essentially 100%, and the products are biodiesel, which is a collection of fatty esters (the collection of several varieties are represented here by the designation R_x), and glycerol.
For the small-scale process (assume steady-state), 140 L/hr of coconut oil is fed to the reactor, along with 540 g/hr solid (pure) NaOH. Based on previous testing, methanol is also fed at a molar flow rate equal to 4.2 times the molar flow rate of coconut oil. A single outlet stream leaves the reactor. The properties of all components are as follows:

a. What is the mass fraction of biodiesel in the reactor output?
b. Later stages of the process separate the components of this reactor output to provide a stream of essentially pure biodiesel. What is the volumetric flow rate of that stream?

Transcribed Image Text:

CH₂OOR₁ CHOOR₂ + 3CH₂OH CH₂OOR3 coconut oil methanol NaOH CH₂OH + CHOH 1 CH₂OH glycerol 3CH₂OOR + biodiesel