Skip to Navigation | Skip to Content

Calvin College Engineering
Senior Design Team 16

"It's Not Easy Being Green" 

Project Description

Our project is to design in detail a pilot plant for the production of poly-beta-hydroxybutryate (PHB). PHB is a natural polymer with physical properties similar to polypropylene produced by some strains of bacteria. As such, it is completely biodegradable. Until recently, the only way to produce PHB has been through fermentation using bacteria, which is very expensive. Now, however, Geoffrey Coates, a chemist at Cornell University, has developed catalysts that allow the synthetic production of PHB from carbon monoxide and propylene oxide. This process potentially could reduce the cost of PHB compared to the fermentation method.

Our team will design all the necessary equipment to construct a pilot plant for PHB production andperform an economic analysis of the process.

Return to Top 

Status - Finished!

Our team has developed a detailed P&ID for the entire process. We will utilize an agitated bubble tank reactor to react propylene oxide with carbon monoxide utilizing the first catalyst developed by Dr. Coates. The catalyst is recovered and recycled using a membrane reactor. Unreacted propylene oxide is removed from the product beta-butyrolactone by distillation. The beta-butyrolactone is then polymerized in a plugged flow reactor with the second catalyst and extruded as pellets. The P&ID is available to download in Microsoft Visio format. Part 1 Part 2  Part 3.

Our cost analysis has concluded that the break even price for 20,000 kg ofPHB in our pilot plant is $19.36/kg. This is very high, even compared to other bioplastics. However, this cost can be reduced considerably by increasing the amount of time we are producing. Our current 1000 hours/yr is far from full time production. Additionally, the knowledge gained from this pilot plant would enable us to reduce costs even further upon scale-up to a full sized production facility. Thus, we are optimistic that this process could be feasible on the industrial scale.

The Team 

the chemies

Download the .pdf of our PPFS report here
Download our first presentation here
Download our second presentation here
Download our third project presentation here
Download our fourth project presentation here
Downloat our final design report here

Return to Top