CHE.01 Plastic to Fuel: From Waste to Vroom

• Maryam Alani
• Mohamed Mostafa
• Jocelyn Alinn Ortega
• David Pulido

Plastic is one of the most commonly used materials in daily life due to it being lightweight, low cost, and high machinability. About 36 percent of all plastics produced are used in packaging for single use. However, one of the major concerns of plastics usage is the disposal of the waste plastic. Around 85 percent of which end up in landfills or as unregulated waste and more than 10 million tons of plastic are dumped into the ocean every year. Furthermore, 25 percent of all the plastic waste is recycled and is only recycled once before being thrown into landfills and oceans. To help resolve the issue of plastic waste, conversion of plastics of synthetic fuels can be accomplished and effective long term. The goal is to design a catalyst cracking process to deal with the accumulating plastic waste. This process utilizes pyrolysis of plastic waste being shred and then mixed to be melted down in a furnace. The plastic will be from hospitals in California due to the number of plastics needed to keep their instruments sterilized. The mixture consists of 25 percent of polystyrene, 25 percent of polyethylene and 50 percent of polypropylene. The solid plastics then enter the furnace at 500 degrees Celsius causing the plastic to break down into smaller molecules and then the molecules are carried by a stream to the catalytic reactor. The percentage of plastics and the use of a silicone alumina allow for a 90 percent conversion of a wide range of hydrocarbons, mainly distributed within C1 to C22.This catalyst gives way a yield of 1 wt percent light propylene gas (LPG), 63 w percent gasoline, and 27 wt percent diesel. These products are separated by going through two distillations towers. The deactivated catalyst goes from the reactor to the catalyst regenerator. The regenerator burns the carbon and makes flue gas, which is scrubbed off in the wet scrubber and sent to nature while the activated catalysts go back into the reactor. In summary, the process of catalyst cracking will produce a rate of 270,000 tons of synthetic fuel per year utilizing a feed rate of 300,000 tons per year of plastic waste. This results in 1,070 tons/year of LPG, 47,000 tons/year of gasoline and 19,700 thousand tons/year of diesel. The results are estimated using experimental data from similar processes found in literature. While there are limited studies focused on catalytic pyrolysis of polystyrene, polyethylene, and polypropylene plastic waste, theoretical calculations based on Aspen Plus simulation are crucial. These results can serve as a reference for practical applications. Simulating the entire process can open up the potential for implementing this technique on a large-scale or in real-world settings.