Thermo-catalytic pyrolysis of polystyrene in batch and semi-batch reactors: A comparative study

Area of Science:

• Chemical Engineering
• Materials Science
• Polymer Chemistry

Background:

• Chemical recycling of waste polymers is crucial for sustainability.
• Thermo-catalytic pyrolysis offers a route to convert polymers into valuable chemicals.
• Polystyrene (PS) is a suitable feedstock for chemical recycling due to its complete recyclability.

Purpose of the Study:

• To comprehensively study the thermo-catalytic pyrolysis of polystyrene (PS).
• To investigate the impact of reactor type (batch vs. semi-batch) and catalyst arrangement on product yields.
• To identify optimal conditions for enhanced recovery of oil and styrene monomer (SM).

Main Methods:

• Thermo-catalytic pyrolysis of PS was conducted in batch and semi-batch reactors at 400°C.
• Catalyst arrangement (mixed vs. layered) and feed to catalyst ratio were varied.
• Residence time and carrier gas flowrate were investigated for their effects on product distribution.

Main Results:

• The semi-batch reactor demonstrated superior performance over the batch reactor for both thermal and catalytic pyrolysis.
• A layered catalyst arrangement yielded more oil and higher styrene monomer (SM) selectivity than a mixed arrangement.
• Carrier gas flowrate influenced the overall product distribution.

Conclusions:

• Semi-batch reactors are more effective for PS pyrolysis than batch reactors.
• Layered catalyst arrangements optimize oil and SM production.
• Optimized process parameters are key for efficient chemical recycling of polystyrene waste.