Abstract: Provided is a novel regenerative heat exchanger and a method for heating a gas in the heat exchanger. The regenerative heat exchanger features a chamber separated into a plurality of annular concentric spaces, including: a first, inner annular space defining a hot collection chamber; a second, outer annular space concentric to and around the first space defining a cold collection chamber; and a third annular space defining a heat exchange zone concentric to and between the first and second spaces. The heat exchange zone contains a particulate heat transfer material. The third space is supported on the inside by a concentrically disposed hot grid, and the external diameter of the third annular space is less than about double the internal diameter of the third annular space. The invention has particular applicability to the feeding of hot blast to a blast furnace in the iron making industry.

Abstract: Provided are novel gas permeable bricks of a refractory material suitable for use in a hot grid of a regenerative heat exchanger. In accordance with one aspect of the invention, the brick has an inner face and an outer face on opposite sides of the brick. One or more cavities extend from the inner face partially into the brick. A plurality of channels for each of the cavities extend from the outer face to the cavities. The cavities and channels allow a gas to pass through the brick. Also provided is a hot grid suitable for use in a regenerative heat exchanger formed from a plurality of the bricks.

Abstract: An electric arc furnace is provided for the production of steel by melting metal between electrodes. The electric arc furnace comprises gas injectors provided with respective cooling chambers placed in a wall of the furnace, wherein at least one single chamber is associated with at least two injectors in order to cool each injector. Each injector is angled in a manner appropriate with respect to a corresponding gas injected thereby and to a corresponding function thereof, wherein the orientation axes of the injectors are not parallel.