Primetals Technologies recently received the final acceptance certificate (FAC) for revamping the continuous pickling line for hot-rolled strip at the Okayama plant of Tokyo Steel Co. The project included installation of a polypropylene iBox pickling tank with acid concentration control. Additionally, a 50-ton tension leveler type scale breaker has been built. As an energy-saving pickling system, the iBox has been delivered to 23 integrated steel plants worldwide.
Maintaining productivity while saving energy
The system installed at the Okayama plant achieves the same productivity at hot descaling and reduction in energy consumption with both integrated and EAF based steel plants. The project scope involves replacing the old cross-injection pickling system of the acid-resistant brick lining with the iBox. Since it is made of polypropylene, the iBox improves pickling capacity without using an electric pump. These were required in conventional jet pickling tanks.
The iBox has immersion boxes inside through which strips travel guided by rolls and skids. Formed by the immersion boxes, a narrow rectangular channel generates a strong shear flow used in the pickling process for accelerating the acid-liquid reaction. In addition, the Acid Concentration Control System (ACCS) regulates acid supply in each tank by using Primetals Technologies’ algorithm to predict the descaling distribution and pickling reaction. The pickling line processes hot-olled coils ranging from 1.5 to 6.0 millimeters in thickness and 840 to 1.340 millimeters in width.
Tokyo Steel EcoVision
Tokyo Steel operates four domestic production plants. Focusing on green steel, the company has set a long-term environmental vision called “Tokyo Steel EcoVision 2050”. It claims a leading role in terms of environmental awareness and circular economy.
