MISSISSAUGA, ONTARIO — Nova Chemicals Ltd. will install a giant twin-screw extruder to pelletize Advanced Sclairtech polyethylene resins at its new plant in Joffre, Alberta.
Nova announced at the Plast-Ex 98 exhibition in Mississauga that it chose a ZSK 380 extruder, with each screw measuring 380 millimeters in diameter, from Krupp Werner & Pfleiderer Corp. The firms believe it is the largest commercial extruder in the world.
A Krupp Werner & Pfleiderer official said the largest twin-screw units it has built so far are ZSK 320 machines.
The new twin-screw will be able to process 154,000 pounds per hour or more, said Brian Turner, Nova's vice president of business development for polymers, in an interview at the May 12-14 show. It will handle all the output from Nova's Advanced Sclairtech reactor due to begin operating in mid-2000. Nova will pay about C$10 million (US$7 million) for the equipment and is investing about C$385 million (US$269.5 million) in the Advanced Sclairtech resin plant.
Krupp Werner & Pfleiderer director of polyolefins Ronald Adams said in a Plast-Ex interview that Nova's extruder will be a basic ZSK design with a 27:1 length-to-diameter screw ratio. His firm will build it in Stuttgart, Germany, ship it by boat to an undetermined location in Canada and deliver it by truck to Nova in several pieces. The gear box alone will weigh about 130,000 pounds and the assembled extruder could exceed 80 feet in length.
Nova of Calgary, Alberta, is promoting its Advanced Sclairtech resins as alternatives to new metallocene resins. Turner said the new Nova resins have processing properties exceeding current commercial metallocene resins.
Nova will feed melted resin from its reactor directly into the extruder, where it will add low levels of antioxidants or other additives. Adams said because melted resin will enter the extruder it will require only about 6,000 kilowatts of power to process the polymer, a fraction of the power needed when powdered resin is added to such a large extruder.
Adams said his firm has several 320mm twin-screw extruders working around the world and engineers are looking at building a 420mm twin-screw, although no customer yet has ordered such a machine.
Nova's new PE line, the world's largest single-train solution plant, will have capacity of about 850 million pounds per year.
The firm recently announced it will spin off from its parent firm about mid-1998 and become a pure plastics and petrochemicals business.