Development and implementation of a generic blast-furnace expert system

Abstract

The performance of a blast-furnace can be judged by various criteria, such as reductant rate (i.e. the weight of coke and tuyère injectant required to produce 1 t of iron); consistency of product quality, measured in terms of temperature and silicon content; plant availability; and campaign life (the quantity of iron produced before the furnace requires relining or rebuilding). Increasing numbers of sensors mean that a large volume of data is now being made available to the shift controller, and this, combined with reductions in shift manning and the development of new data assessment techniques, makes the process an ideal candidate for an operator guidance system.Corus, the company formed by the recent merger of British Steel and Hoogovens, operates nine blast-furnaces on four integrated sites in the United Kingdom—two in northeast England (Redcar and Scunthorpe) and two in South Wales (Port Talbot and Llanwern); the two furnaces at Llanwern are, however, due to be decommissioned in July, 2001.The first attempt to install a blast-furnace expert system within British Steel was aborted in 1991, but a number of software shells were subsequently assessed by the Computing Applications Section at British Steel's Teesside Technology Centre, and G2, produced by Gensym, was selected as the most appropriate for further developments. A system comprising data acquisition software, a comprehensive relational database, an expert system developed with the use of G2 and a G2 database bridge that allows data to be passed between the database and the expert system was launched at Llanwern in October, 1996, and has operated reliably since then. A similar system was installed at Redcar, the company's largest blast-furnace, with the aim of extending campaign life by maximizing operational stability. The opportunity was taken to redesign the knowledge base, including data access, and the result was a generic shell that can be readily applied to any blast-furnace. Some of these developments were subsequently reapplied to Llanwern. More recently, a system has been developed for the Port Talbot No. 4 blast-furnace and another covering the two larger furnaces at Scunthorpe is being commissioned. An adaptive principal-component analysis algorithm that accounts for normal process variations was also developed as a project within the EU-funded Fourth Framework.