7TH EUROPEAN COKE AND IRONMAKING CONGRESS - ECIC 2016

In November 2014 the pulverized coal injection (PCI) at blast furnace A in Linz was started followed by the coal injections into blast furnace 5 and 6 in February 2015. Up to this moment reducing agents like heavy oil, crude tar, coke oven gas, waste plastics and natural gas have been injected into the three blast furnaces (BFs). Due to the limited space around the BFs it was decided to implement the new PCI plant as two separate units. The coal preparation unit for grinding and drying (GAD) and the injection unit located next to the BFs are connected by an intermediate pneumatic conveying (dense phase) of about 1.800m. In order to minimize the potential risks of a break down in the coal grinding unit and to guarantee the smooth flow of fine coal within in the conveying pipes a raw coal preparation plant equipped with crushers, screens, magnetic and non-magnetic separators was installed in front of the coal grinding unit with the aim of removing metals, wood, plastics, etc. After the start up and ramping up the injection rate the optimisation of the injection control system was one of the key challenges.