Published December 2008
To reduce the cost of polyethylene production by “economy of scale”, significantly larger world-scale polyethylene plants are being designed. World-scale single-line capacity slurry loop plants have increased to around 300,000 to 400,000 metric tons per year. Larger slurry loop plants with a capacity of 500,000 to 600,000 metric tons per year have been designed. Recent developments in the INNOVENE™ S slurry loop technology are discussed in this review. To increase the production capacity of a single-line slurry loop plant, a larger reactor loop volume is used. Typically the reactor loop volume is increased by increasing the reactor length while maintaining the reactor internal diameter at approximately 24 inches (600 mm). Increasing the reactor diameter has been considered undesirable because of concerns about increased fouling, reduced heat transfer, and reduced polymer production rate and homogeneity. Recent Innovene Manufacturing Belgium’s patents disclosed the use of larger diameter loop reactor for polyethylene production. The loop reactor has an internal diameter of at least 28 inches (700 mm). Increased fouling and reduced heat transfer were not observed. The process economics for bimodal polyethylene production using two slurry loop reactors in series are evaluated based on a plant capacity of 400,000 metric ton per year.
