Catalytic Thermal Depolymerization by Cielo

Team 2: Catalytic Thermal Depolymerization Presentation Video https://mediaspace.carleton.ca/media/Presentation+of++Team+Findings+%28Team+2%29/1_6cw0al8n

Image source: https://phys.org/news/2019-10-big-firm-products-worst-plastic.html

Particle Size Reduction: Quinn Hyland Dunphy

Before the process can begin the waste particles need to be reduced into tiny particles. One of the all-purpose methods used effectively with such a wide variety of materials is called a particle mill or Jet mill. Jet mills are designed to take in large particles and spit out small ones. Jet mills use high pressure air or inert gas at high speeds to reduce particle size by using the drag of the air and colliding particles together.

Compressed air enters cylinders on the side of the jet mill, the air is compressed at 5.5 times the pressure of our atmosphere. The high-pressure air is spit out by tiny nozzles. High pressure air is needed to transform into kinetic energy for the particles. A smaller area produces a higher pressure, the force of the high-pressure air is acting on an already small area particle, aiding in it’s speed. Once the particles gain enough momentum they start to collide and break each other up into tiny pieces, a larger particle can also be introduced to speed up the rate.

Using Water as a Carrier Fluid to Transport Solids: Craig Kirk

Cielo has developed a chemical process for turning solid waste into fuel. After the solid waste has been broken into particle sized pieces, water is introduced into the reaction mixture creating a slurry. The water is used as a carrier liquid to transport the solid waste through the remaining steps of the process. Water is an effective carrier fluid due to its low viscosity which allows it to flow quickly through the process. The water is crucial to the transportation of the waste, but it is not part of any chemical reactions. The water is removed from the slurry after it has reached its destination and is recycled back to the beginning to transport more solids.

Using a Catalyst to Reduce the Heat Required to Covert Plastic to Fuel: Andrew Beeston

After the plastic material has been broken down and added to the carrier fluid it is transported to the reaction vessel to be converted into fuel. Before the biomass slurry is added to the reaction vessel the slurry is heated to 150 °C to remove any water from the carrier fluid. The biomass slurry is then added to a reaction vessel along with a catalyst. The catalyst serves to lower the activation energy of the reaction so it can take place at a lower temperature. In the reaction vessel the biomass slurry is heated to 240°C – 270 °C and with the help of the catalyst the plastic material is broken down into hydrocarbon fuels. The hydrocarbons are then removed from the reaction vessel to be later distilled.

Separating Fuel Fractions From Remaining Biomass Slurry: Bridget Liddy

To remove the hydrocarbon distillate fractions (the components that will be refined to produce fuel) from the remaining biomass slurry, the slurry is distilled repeatedly. Distillation is the heating of a liquid to a specific temperature at which a target component of the liquid becomes a gas. By vaporizing the target component, it can be removed from the rest of the liquid and then cooled to condense it back into liquid from. The slurry is heated using plate and shell heat exchangers, which use large plates to increase the surface area to transfer heat through the heat transfer method of convection. Aerial coolers are used to reduce the temperature of the slurry until it is back in liquid form. Aerial coolers cool the slurry through convection by passing the liquid in tubes, used to increase the surface area, over large fans. The steps of heating and cooling are repeated to recover the three fuel types: naphtha, kerosene and diesel.