Spheripol process technology produces propylene-based polymers including homopolymer polypropylene (PP) and many families of random and heterophasic impact and specialty impact copolymers.
In the Spheripol process, homopolymer and random copolymer polymerization takes place in liquid propylene within one or two tubular loop reactors (1) in cascade. Heterophasic impact copolymerization can be achieved by adding a gas-phase reactor (3) in series.
Unreacted monomer is flashed in a two-stage pressure system (2, 4) and recycled back to the reactors mostly by condensation with CW and pumping. This improves yield and minimizes energy consumption. Dissolved monomer is removed from the polymer by a steam sparge (5). The process can use lower-assay chemical-grade propylene (93% to 95%) or the typical polymerization-grade (99.5%).
Yields: Polymer yields of 40,000–60,000 kg / kg of supported catalyst are obtained. The polymer has a controlled particle size distribution and an isotactic index of 90%–99%.
Economics: The Spheripol process offers a broad range of products with excellent quality and low-capital and operating costs. Consumption, per metric ton of PP (polymerization):
Propylene and comonomer, ton 1.001
Catalyst, kg 0.016–0.025
Electricity, kWh 80*
Steam, kg 280
Water, cooling, metric ton 90
Products: The process can produce a broad range of propylene-based polymers, including homopolymer PP, various families of random copolymers and terpolymers, heterophasic impact and speciality impact copolymers (up to 25% bonded ethylene), as well as high-stiffness and high-clarity copolymers.