NKK to Expand Waste Plastics Recycling For Blast Furnace Feed
Encouraged by favorable progress in its waste plastics recycling and blowing operations at the Keihin Works' No.1 blast furnace (BF), NKK has decided to expand such operations at the Fukuyama Works as well. While the Keihin system, commissioned in October 1996, is designed to recycle industrial waste plastics, the new Fukuyama system will be capable of handling municipal waste plastics containing polyvinyl chloride (PVC) as well, a first attempt in Japan. NKK's plans are to install a 30,000 tons-peryear integrated waste plastics recycling and blowing system at the Fukuyama Works' No.3 BF. The first phase of the ¥4-billion construction project is due to be completed in March 2000, enabling initial operations to recycle about 15,000 tons of waste plastics a year. With the completion of the second phase scheduled for March 2001, the whole system will become fully operational. In the Fukuyama Works system, a collected waste plastics pretreatment system will include a primary crusher, ballistic separator, magnetic and wind-powered waste sorters, secondary crusher, PVC separation and removal system, granulator and a storage silo. The pretreatment system will be built in an industrial complex near the works. The blowing system to be built next to the works' No.3 BF will include a receiving hopper and injection station to blow processed plastics into the furnace through tuyeres. The blown-in plastic pieces will be gasified and act as a reducing agent for iron ores, partially replacing coke in conventional use. Recycling of municipal waste plastics for commercial blowing into BFs has been hampered due to such problems as the corrosion of in-furnace walls induced by PVC. In an effort to effectively remove PVC from municipal waste plastics prior to blowing, NKK, working jointly with the Japan Chemical Industry Association and other research groups, has developed a centrifugal gravity PVC separation system. The Fukuyama system will incorporate this advanced PVC removal system. Separated PVC will eventually be reused after hydrogen chloride is removed. NKK is also undertaking a separate research project using a pilot plant to recover hydrogen chloride from PVC for reuse at steelworks and other plants. Recycling of waste plastics for feed into BFs offers at least 80% or higher energy efficiency in the furnace, surpassing other recycling methods in terms of energy and resource conservation. It also helps reduce emissions of carbon dioxide, eliminate generation of harmful by-product gas and solve pressing issues involving landfill sites, thereby significantly contributing to environmental protection. The Keihin system has already reached full operational capacity of 30,000 tons of industrial waste plastics a year, with a feed from about 300 contracted companies nationwide. Collected waste is transported by trucks. With a view to establishing a further cost-efficient and environment-conscious transportation system, NKK recently tied up with Japan Freight Railway Co. (JRF). The alliance will enable NKK to fully utilize JRF's nationwide railway network system to further rationalize transport of waste plastics both to the Keihin and Fukuyama Works. While broadening the scope of its waste plastics recycling operations for BFs, NKK intends to promote a more comprehensive recycling venture by integrating the versatile environmental recycling technology the company has accumulated through its traditional steelmaking and engineering operations. |
