A process and plant for preheating a metal charge fed in continuous to an electric melting furnace through a preheating tunnel provided with side walls, a vault and a horizontal conveyor, wherein the metal charge is enveloped in countercurrent by fumes or exhaust gases exiting from the electric melting furnace, includes causing an air intake from the surrounding environment through openings along the preheating tunnel to complete the combustion of the fumes or exhaust gases. The intake is regulated by acting on suction fans and/or on the openings, based on measurements by temperature sensors and/or the composition of the outgoing gases in or downstream of the terminal part of the tunnel. The metal charge is enveloped by jets of gas ejected through a plurality of nozzles arranged non-uniformly longitudinally on the vault of the tunnel, with a greater concentration on the top of the vault of the tunnel.

Provided is a method of operating a blast furnace, including generating a regenerative methane gas using a blast furnace by-product gas, and blowing a blast gas and a reducing agent into the blast furnace from a tuyere, in which the blast gas is oxygen gas, the regenerative methane gas is used as at least part of the reducing agent, and the oxygen gas and/or the regenerative methane gas is preheated before being blown into the blast furnace from the tuyere.

A device (1) for drying and/or preheating metallic and/or non-metallic materials, preferably scrap, comprises a receiving container (3) and a scrap basket (7) which is arranged in the receiving container (3) and has a gas-permeable bottom area (9). The receiving container (3) has at least one process gas inlet line (6) in its wall (4), via which a process gas with a temperature in the range from 200 to 1600° C. can be introduced into the receiving container (3), and at least an injector nozzle (19) arranged coaxially within the at least one process gas inlet line (6) via which a cooling gas can be introduced into the process gas.

The invention concerns a process for operating a fired furnace which is heated using a fuel gas stream and forming a combustion product stream, wherein heat of at least part of the combustion product stream is used in forming a steam stream. It is provided that at least a part of the steam stream is subjected to a high-temperature electrolysis to form a hydrogen-containing and an oxygen-containing material stream, and that at least a part of the hydrogen-containing material stream is used as the fuel gas stream. A corresponding arrangement is also the subject of the invention.

A method of cooling a liner in a plasma chamber. A recycle gas is contacted with or passed through the liner to cool the liner and pre-heat the recycle gas. The pre-heated gas is then recycled through the plasma chamber to become part of the plasma forming process. The method further comprises the liner is graphite, the recycle gas passes through at least one cooling channel present in the liner, at least one of the cooling channels are covered with at least one removable liner/channel cover, carbon deposits are formed from the presence of hydrocarbons in the recycle gas, at least one channel is formed in a spiral cooling channel pattern, at least one channel is formed in a substantially straight cooling channel pattern, and a plenum to aid in the production of an even distribution of cooling gas in the channels.

Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.

A furnace for thermal treatment, in particular for carbonization and/or graphitization, of material, in particular fibers, in particular fibers of oxidized polyacrylonitrile PAN. During the thermal treatment, a pyrolysis gas is released from the material. The furnace includes a housing, a process space, which is located in the interior of the housing and is delimited by a process space housing and through which the material can be fed, a heating system for heating a process space atmosphere prevailing in the process space, and an extraction system for suctioning process space atmosphere laden with pyrolysis gas from the process space. The extraction system has at least one suction device having a suction channel, which is delimited by a channel wall and which is connected to the process space by means of a suction opening. The suction opening is arranged in a region of the process space in which, during operation of the furnace a temperature prevails at which no or only moderate chemical reactions occur between the pyrolysis gas and the process space housing and/or the channel wall.

Employing furnace combustion gases for both thermochemical regeneration and heating of regenerators to preheat oxidant for the furnace provides synergistic efficiencies and other advantages.

An overflow system for a doorway exhaust hood on a metal melt furnace having an eductor gas circulator. The system includes a manifold with an inlet near the hood's lower lip, and a conduit between the manifold and eductor. A blower draws gas into the manifold and urges that gas through the conduit, into the eductor, and into the furnace. Sensors detect when the door is open and the volatiles level under the hood. An electronic controller instructs the blower to draw exhaust gases through the manifold when the door is open and the volatiles level exceeds a predetermined level.

A process of calcining aluminium hydroxide (Al.sub.2O.sub.3.3H.sub.2O) to form alumina (Al.sub.2O.sub.3), for example in an alumina plant, such as a Bayer process plant, is disclosed. The process comprises combusting hydrogen and oxygen and generating steam and heat 5 and using the heat to calcine aluminium hydroxide and form alumina and more steam. An apparatus is also disclosed.