Energy Efficiency in Secondary Cooling - New Generation of Air-Mist Nozzles With Reduced Air Consumption and High Cooling Efficiency

摘要

Increasing cost pressure and legal requirements to reduce the CO_2 emissions are forcing steel producing companies to improve the energy efficiency of their plants. The secondary cooling system of continuous casting machines with air-mist cooling provides opportunities for savings. In particular, the consumption of compressed air causes significant energy consumption and operating costs. These facts were among others the basis to develop a new generation of air-mist nozzles for slab casting. The focus of this development was the reduction of air consumption of the nozzle significantly while maintaining the cooling efficiency. In addition, a high water turndown ratio, a constant spray angle and a uniform spray pattern should be achieved as well as compatibility to existing well-proven Mastercooler~R series. The result of this development is the new nozzle series Slabcooler~R Eco which satisfies these demands and provides an air saving potential of about 30 % over a large turndown range. Extensive testing of the spray characteristics in terms of spray appearance, liquid distribution, pressure-flow rate and cooling efficiency has been conducted. The potential savings are based on a comparison with an equivalent nozzle of the Mastercooler~R series. The Slabcooler~R Eco series offers the opportunity to reduce air consumption of the secondary cooling and thus significantly contribute to energy efficiency and cost savings. The existing productivity and quality will be maintained without mayor modifications to existing secondary cooling systems.