The regenerative-combustion burner offers the following benefits:

1. Equipment size is compact due to the use of high-performance ceramic honeycomb for the regenerator, allowing efficient heat recovery.

2. With the burner combusting alternately every 30 seconds, it is possible to preheat the air in the furnace to as high as 1, 330°C, compared with the conventional 600°C level.

3. Use of a unique two-stage combustion technology (involving high-temperature preheated air and optimized fuel supply systems) allows uniform flame temperature distribution in the furnace, resulting in remarkably low NOx emission levels.

4. Already employed at NKK's hot-rolling reheating furnaces, batch furnaces for plates and other facilities average 30% or higher energy savings and 60% reduction in NOx emissions have been realized.

Completing the basic technology in 1992, NKK introduced the new burner system (using 76 units in 38 pairs) to the No.3 continuous slab reheating furnace (maximum capacity: 230 tons/hour) of Fukuyama's No. l hot strip mill in 1996. This was the world's first example of industrial application in a large-scale reheating furnace. Applications of the burner have since steadily expanded to a variety of industrial furnace sectors, totaling 1, 864 units in use to date, including 904 units at steelworks, 752 units in automobile and non-ferrous metal industries, 96 units in ceramic-related operations and 112 other uses.

In light of the growing concern over global warming and evolving challenges for preserving the environment, NKK sees the use of the regenerative burner spread widely in Japan's industrial furnace sector, which owes about 20% of the country's total energy consumption, and in a range of consumer sectors. To contribute to energy conservation on a global scale, NKK also seeks to promote joint application projects in this field with advanced countries and positive technology transfers to industrializing countries.