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.

The present invention relates to a method for pneumatically blowing a powdery substitute reducing agent in a dense flow process, by means of a transport gas, into a gasification reactor, or via a tuyere into a blast furnace. The substitute reducing agent is gasified in a gasification reaction. The transport gas comprises a fuel gas, the constituents of which or the oxidation constituents of which are at least partly involved in the gasification reaction.

A method for operating a blast furnace includes blowing pulverized coal and oxygen from an upstream lance configured by a double tube. LNG is blown from a downstream lance on the downstream side in a hot air blast direction, oxygen is supplied from the upstream lance, and the pulverized coal whose temperature has been increased by the combustion of the LNG is combusted along with the supplied oxygen or oxygen in an air blast. With respect to a direction perpendicular to the hot air blast and a downstream direction of the hot air blast, a blowing direction of the LNG from the downstream lance with respect to the blast direction ranges from 30 to +45. A blast pipe circumferential direction angle at a blowing position of the LNG from the downstream lance with respect to where the upstream lance is inserted into a blast pipe ranges from 160 to 200.

A method of detecting an abnormality in a blast furnace, wherein the abnormality causes clogging of a tuyere unit of the blast furnace, the method including capturing an image of a raceway unit through an in-furnace monitor window disposed at the tuyere unit; and determining that the abnormality has occurred when a brightness of the captured image is lower than or equal to a predetermined brightness threshold and a rate of decrease in the brightness is lower than or equal to a predetermined brightness-decrease-rate threshold.

A fluid assisted particle injector for a metallurgical furnace, comprising: an injector tube having an entrance end, an exit end and a removable tip; a cover tube disposed over the injector tube; a fluid and particle injector port in line with the longitudinal center axis of the injector tube and a secondary fluid port for directing pressurized fluid over the outside of the injector tube and within the cover tube; the injector tube defining a tapered internal bore having a particle entrance end and a particle exit end, wherein the diameter of the particle exit end is smaller than the diameter of the particle entrance end.

A solids injection lance includes (a) a tube that defines a passageway for solid feed material to be injected through the tube and has an inlet for solid material at a rear end and an outlet for discharging solid material at a forward end of the tube and (b) a puncture detection system for detecting a puncture in the solids injection tube.

The invention relates to an optical monitoring system (26) for monitoring operating conditions in a tuyere zone of a blast furnace. This system comprises a light deflecting device (40) with a peep sight (28) arranged in a first face (46) of the light deflecting device (40) and an optical sensor (30) arranged in a second face (48) of the light deflecting device (40). A light deflector (41) is arranged within the light deflecting device (40) for directing incident light from the tuyere zone towards the peep sight (28) and towards the optical sensor (30). The light deflecting device (40) comprises a housing (56) with a spherical body (60) rotatably arranged therein. The spherical body (60) comprises three passages: a first passage (62) which is, when the light deflecting device (40) is connected to the rear portion of the blowpipe (18), facing the tuyere for allowing incident light from the tuyere zone to enter the spherical body (60); a second passage (70) facing the peep sight (28); a third passage (72) facing the optical sensor (30). The first, second and third passages (62, 68, 72) are configured so as to meet each other within the spherical body (60). The light deflector (41) is arranged within the spherical body (60) at the intersection of the first, second and third passages (62, 68, 72). Furthermore, the light deflecting device (40) comprises an opening (76) in a third face (50) of the housing (56) for accessing the spherical body (60) for allowing rotation of the spherical body (60) within the housing (56). The spherical body (60) comprises a socket (78) facing the opening (76) in the third face (50). The opening (76) is a guiding slot (86) whose width is substantially the same as a diameter of the socket (78).

A method is provided for operating a blast furnace by blowing a solid reducing material, a flammable gaseous reducing material and a combustible gas into a blast furnace from tuyeres through a lance into a blast furnace, wherein a parallel type lance prepared by bundling three independent blowing tubes in parallel and integrally housing them into an outer tube is used, and either one or both of the gaseous reducing material and the combustible gas and the solid reducing material are simultaneously blown through the respective blowing tubes, while the blowing tube for the solid reducing material and the blowing tube for the gaseous reducing material are positioned above the blowing tube for the combustible gas in the blowing through the parallel type lance as well as a lance structure thereof.

A method is provided for operating a blast furnace by blowing at least a solid reducing material and a combustible gas into the furnace through tuyeres with a lance inserted into a blowpipe, wherein a tube-bundle type lance obtained by bundling a plurality of blowing tubes is used and when only a solid reducing material or two kinds of a solid reducing material and a combustible gas or three kinds of a solid reducing material, a combustible gas and a gaseous reducing material is simultaneously blown into an inside of the blast furnace through a tube for blowing the solid reducing material, a tube for blowing the combustible gas and a tube for blowing the gaseous reducing material in the tube-bundle type lance, two or more tube-bundle type lances are inserted into the blowpipe to approximate their front ends to each other and blowing is performed so that the respective blowout streams interfere with each other in the blowpipe.

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.