School of Rock: Chemical Engineering Practical Applications

Posted on: April 27th, 2012
Source: University of California at Santa Barbara - Chemical Engineering Department

School of Rock - Band Flyer
6th Annual Professional Development in Chemical Engineering Conference - UC Santa Barbara

A symposium focused on the practical "how to" of chemical engineering.  The set list included the "ChE Instruments" - process engineering of pumps, piping, reactors and heat exchangers, "Under Pressure" - process safety components, and "How Not to be a One Hit Wonder" - basics of process development and project management for chemical engineering undergrads and graduate students.


Biodiesel Process Engineering to Survive, Thrive, and Drive Today's Green Fuel Markets

Posted on: October 12th, 2011
Source: Active Communications International
US Biodiesel Conference - Houston, TX
Short Course Presented by: Marc Privitera, PE and Christina Borgese
Conference Chair and Sponsor: PreProcess, Inc.

Waste Grease Feedstock Conversion Using Supercritical MeOH

Posted on: September 26th, 2011
Source: Southern Waste Information eXchange, Inc. (SWIX)
4th Annual Waste-to-Fuels Conference and Trade Show - San Diego, CA
Presented by Marc Privitera, PE - PreProcess, Inc.

Biodiesel Reaction and Separation Technology

Posted on: September 8th, 2011
Source: Biodiesel Magazine

Biodiesel Reaction and Separation TechnologyThe chemistry and engineering behind the biodiesel process

By Christina Borgese and Marc Privitera | September 08, 2011

Biodiesel reaction and separation methods range from the time-honored large batch tanks with long residence time reactions and water washes for product separation to intensification, enzymatic, and supercritical reactions coupled with distillation and mechanical separation methods. Selecting the best reaction and separation method for the process depends upon the feedstock characterization, a process we covered in the August issue of Biodiesel Magazine. This installment highlights the specific drivers behind selecting the best reaction and separation techniques while considering process throughput, overall conversion efficiency and plant economics.

The biodiesel reactions have three elements for driving the conversion of the feedstock to the finished product: mixing, molar ratio, and residence time. In simple terms, you have to present the reagent molecules with the opportunity, enough energy and enough time to react. It’s kind of like a seventh-grade school dance.

Mixing is the first operation to consider. Mixing drives the reagent interface surface area. The interface surface area is increased by decreasing through shear the dispersed phase liquid droplet size to the smallest size possible. In the usual batch reactor, the mixing is motivated by an agitator. Many high-shear flow strategies have been successfully employed to intensify phase interaction. The number of molecules motivated to react is driven by the surface area of the two immiscible phases.

Quick and Dirty Feedstock Characterization

Posted on: July 11th, 2011
Source: Biodiesel Magazine
By Christina Borgese and Marc Privitera, PE

Practical advice for cash-strapped community-scale biodiesel plants

Feedstock characterization, process conversion and fuel finishing are the building blocks of biodiesel production. Of the three, feedstock characterization is usually underestimated. The lack of depth in the understanding of feedstock’s impact on the business plan has lead to challenges that might have been avoided for smaller scale producers. This article on feedstock is the first of three installments to discuss the building blocks of biodiesel production.

Nontraditional methods to process higher free fatty acid (FFA) feedstocks are more technically complex compared to traditional systems. High FFA feedstocks include yellow grease, brown grease, tallows, and algal oils. Yellow grease is primarily comprised of restaurant and cooking wastes. Brown grease typically comes from grease trap waste, dissolved air flotation  skimmings, agricultural spoils and meat cut waste. Algal oil is only now emerging as another feedstock. Tallows and rendered fats typically have a high existing market value.

The National Renderers Association defines yellow grease as no more than 15 percent FFA and no more than 2 percent MIU (moisture, insolubles and unsaponifiables). The historical reference on FOG, Bailey’s Industrial Oil and Fat Products, defines brown grease as having an FFA level between 15 and 50 percent. There is much debate throughout the industry on how exactly to define brown grease. In reality the nomenclature is inconsequential. What really matters is the actual FFA and MIU content received at the plant and whether or not the system is capable of processing the material. A rookie mistake is negotiating a contract to buy yellow or brown grease without the needed characterization. 
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