An air blast system for melting furnaces includes: a supply unit supplying hot air into a melting furnace; a bustle pipe connected to the supply unit; a tuyere stock connecting the bustle pipe to the melting furnace to supply hot air from the bustle pipe to the melting furnace in a distributed manner; and a temperature management module determining whether the tuyere stock is damaged by comparing a temperature of the tuyere stock with a preset reference temperature.

A burner assembly for top combustion hot blast stove including a burner surrounded by a burner shell, where the burner has a circular cross-section; a number of air nozzles arranged for tangentially feeding air to the burner, the air nozzles being connected to one or more air distribution chambers; a number of gas nozzles arranged for tangentially feeding gas to the burner, the gas nozzles being connected to one or more gas distribution chambers; wherein the air nozzles are arranged in one or more inclined or vertical stacked arrays of air nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical air distribution chamber; the gas nozzles are arranged in one or more inclined or vertical stacked arrays of gas nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical gas distribution chamber; and the inclined or vertical air distribution chamber(s) and the inclined or vertical gas distribution chamber(s) are arranged along the circumference of the burner shell.

A burner assembly for top combustion hot blast stove including a burner surrounded by a burner shell, where the burner has a circular cross-section; a number of air nozzles arranged for tangentially feeding air to the burner, the air nozzles being connected to one or more air distribution chambers; a number of gas nozzles arranged for tangentially feeding gas to the burner, the gas nozzles being connected to one or more gas distribution chambers; wherein the air nozzles are arranged in one or more inclined or vertical stacked arrays of air nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical air distribution chamber; the gas nozzles are arranged in one or more inclined or vertical stacked arrays of gas nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical gas distribution chamber; and the inclined or vertical air distribution chamber(s) and the inclined or vertical gas distribution chamber(s) are arranged along the circumference of the burner shell.

The invention relates to a regenerator assembly and an inlet arrangement for collection of carry over (10) for a vertical regenerator (80) of an end-port furnace (90) comprising: an inlet wall comprising an opening for a port for gas exchange, e.g. towards or from an end-port furnace; a target wall being arranged such, that most of the via the inlet wall incoming hot gas is initially deflected at the target wall; a barrier wall comprising a recess for gas exchange, e.g. from or towards a pass of the regenerator, a (at least one) delimiting wall or walls, such as a floor and/or a roof and/or a sidewall; the inlet wall, the target wall, the barrier wall and the delimiting wall or walls define the inlet arrangement for collection of carry over such that a gas flow entering the inlet arrangement for collection of carry over via the port will exit the inlet arrangement for collection of carry over via the recess or vice versa; and the ratio between the area of the barrier wall and the total area in the plane of the barrier wall, limited by the delimiting wall or walls, such as the floor, the roof, the inlet wall and the target wall, is in the range of 20% to 40%.

To provide a method for operating a blast furnace with which the combustion efficiency of a solid fuel, such as pulverized coal, is improved, thereby making it possible to improve productivity and reduce CO.sub.2 emissions. Pulverized coal and LNG are blown from an upstream lance configured by a double tube, and oxygen is blown from a downstream lance on the downstream side in a hot air blast direction, so that oxygen used for preceding combustion of the LNG is supplied from the downstream lance, and the pulverized coal whose temperature has been increased by the combustion of the LNG is combusted along with the supplied oxygen. When a direction perpendicular to the hot air blast direction is designated as 0, and a downstream direction and an upstream direction therefrom in the hot air blast direction are designated as positive and negative, respectively, a blowing direction of the oxygen from the downstream lance with respect to the blast direction ranges from 30 to +45, and a blowing position of the oxygen from the downstream lance with reference to a position at which the upstream lance is inserted into a blast pipe ranges from 160 to 200 in terms of a blast pipe circumferential direction angle.

To provide a method for operating a blast furnace with which the combustion efficiency of a solid fuel, such as pulverized coal, is improved, thereby making it possible to improve productivity and reduce CO.sub.2 emissions. Pulverized coal and LNG are blown from an upstream lance configured by a double tube, and oxygen is blown from a downstream lance on the downstream side in a hot air blast direction, so that oxygen used for preceding combustion of the LNG is supplied from the downstream lance, and the pulverized coal whose temperature has been increased by the combustion of the LNG is combusted along with the supplied oxygen. When a direction perpendicular to the hot air blast direction is designated as 0, and a downstream direction and an upstream direction therefrom in the hot air blast direction are designated as positive and negative, respectively, a blowing direction of the oxygen from the downstream lance with respect to the blast direction ranges from 30 to +45, and a blowing position of the oxygen from the downstream lance with reference to a position at which the upstream lance is inserted into a blast pipe ranges from 160 to 200 in terms of a blast pipe circumferential direction angle.

A burner assembly for top combustion hot blast stove including a burner surrounded by a burner shell, where the burner has a circular cross-section; a number of air nozzles arranged for tangentially feeding air to the burner, the air nozzles being connected to one or more air distribution chambers; a number of gas nozzles arranged for tangentially feeding gas to the burner, the gas nozzles being connected to one or more gas distribution chambers; wherein the air nozzles are arranged in one or more inclined or vertical stacked arrays of air nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical air distribution chamber; the gas nozzles are arranged in one or more inclined or vertical stacked arrays of gas nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical gas distribution chamber; and the inclined or vertical air distribution chamber(s) and the inclined or vertical gas distribution chamber(s) are arranged along the circumference of the burner shell.

A burner assembly for top combustion hot blast stove including a burner surrounded by a burner shell, where the burner has a circular cross-section; a number of air nozzles arranged for tangentially feeding air to the burner, the air nozzles being connected to one or more air distribution chambers; a number of gas nozzles arranged for tangentially feeding gas to the burner, the gas nozzles being connected to one or more gas distribution chambers; wherein the air nozzles are arranged in one or more inclined or vertical stacked arrays of air nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical air distribution chamber; the gas nozzles are arranged in one or more inclined or vertical stacked arrays of gas nozzles, each inclined or vertical stacked array being in connection with one inclined or vertical gas distribution chamber; and the inclined or vertical air distribution chamber(s) and the inclined or vertical gas distribution chamber(s) are arranged along the circumference of the burner shell.

A method for heating a blast furnace stove includes combusting a fuel with a lower heating value (LHV) of 9 MJ/Nm.sup.3 or less in a combustion zone which is arranged in a combustion chamber in the stove, and causing the combustion gases to flow through and thereby heat refractory material in the stove. The fuel is combusted with an oxidant including at least 85% oxygen, and combustion gases are recirculated into the combustion zone for diluting the mixture of fuel and oxidant therein sufficiently for the combustion to be flameless.

A method for heating a blast furnace stove includes combusting a fuel with a lower heating value (LHV) of 9 MJ/Nm.sup.3 or less in a combustion zone which is arranged in a combustion chamber in the stove, and causing the combustion gases to flow through and thereby heat refractory material in the stove. The fuel is combusted with an oxidant including at least 85% oxygen, and combustion gases are recirculated into the combustion zone for diluting the mixture of fuel and oxidant therein sufficiently for the combustion to be flameless.