Hylsa, S.a.

Hylsa, S.a. De C.v.

Fierro Esponja, S.a.

Grupo Industrial Alfa, S.a.

Enrique R Martinez-Vera

Juan F Price-Falcon

Gilberto Guerra-Garcia

Jorge O Becerra-Novoa

Patrick W MacKay

Eugenio Zendejas-Martinez

Juan A Villarreal-Trevino

Jorge D Berrun-Castanon

Alberto Bustani-Adem

Jose L Tovalin

Francisco Cantu-Hernandez

A process for the gaseous reduction of iron ore to sponge in a vertical shaft, moving bed reactor wherein a hot gaseous mixture of hydrogen and carbon monoxide generated by the internal steam reformation of gaseous hydrocarbon(s), preferably methane or natural gas, is used to reduce the ore without the need for any external catalytic reformer. A reducing gas recycle loop is established to which hydrocarbon and reclaimed waste hot water are fed in the proper proportions as the reducing gas make-up source with the sponge iron produced in the reduction reactor being used to catalyze hydrocarbon reformation, and with the carbon content of the recycled gas being maintained low by removing carbon dioxide therefrom. High overall process thermal efficiency and lowered operating and capital costs are achieved by establishing hot water (and optional steam) loops wherein all process hot water/steam requirements are met through the utilization of hot water discharge from the quench cooler and advantageously also the generation of steam by the reclamation of waste heat from spent hot reducing gas leaving the reactor, thereby eliminating the need for importing costly process steam and reducing the size needed for cooling towers and water treatment units.

Method of reducing iron ore

Start-up method for an iron ore direct reduction process, where in the steady-state process the reducing gases are produced by steam reformation of natural gas catalyzed within the reducing zone of the reduction vessel by the reduced ore present therein. During established steady-state operation, a process gas stream is circulated in a reducing gas loop comprising the reduction vessel, a gas heater, and units to remove H.sub.2 O and CO from the gas circulating in said loop. Natural gas and water are fed directly to the reducing gas loop as make-up reactants for the reformation. At plant start-up there is a complete absence of metallic iron to catalyze the reformation reaction at any temperature, and a complete absence of H.sub.2 or CO so no effective reduction is possible to produce the needed metallic iron. In a multi-stage start-up, the reduction vessel is first charged with iron ore and pressurized by introducing natural gas to said loop. Simultaneously, the temperature is raised to the range of 400.degree. to 600.degree. C. The natural gas cracks, producing a small amount of H.sub.2 and some carbon soot. Second, the temperature is further increased, and injection of water is begun to prevent further carbon deposition, to promote the production of H.sub.2, and to avoid H.sub.2 consumption; until 3% to 8% by volume of H.sub.2 accumulates. Third, at about 750.degree.-820.degree. C., water injection is interrupted favoring the accumulation of hydrogen until a concentration of about 65% is achieved while the temperature of the process gas stream reaches its steady-state value of about 950.degree. C. Fourth, water is again injected to promote the reforming of make-up natural gas within the reduction vessel and all process feeds are adjusted to their steady-state values.

Start-up method for a direct reduction process without an external

A method of operating a vertical moving bed reduction reactor for reducing iron ore to sponge iron and having a reduction zone in the upper portion thereof and a cooling zone in the lower portion thereof to obtain a desired degree of metallization of the reduced ore in said reduction zone and a desired degree of carburization in said cooling zone which comprises supplying to said reactor a predetermined flow of reducing gas comprising carbon monoxide and hydrogen and, varying the ratio of reducing gas flow to said reduction zone to the reducing gas flow to said cooling zone to vary at least one of the amount of metallization attained in said reduction zone and the amount of carburization attained in said cooling zone, maintaining the carbon dioxide concentration in said reduction zone at a value which yields the desired degree of metallization therein and maintaining the carbon dioxide concentration in said cooling zone at a value which yields the desired degree of carburization in said cooling zone.

Method for controlling metallization and carburization in the reduction

The present invention relates to a process for the production of metallic iron through direct reduction of iron ores and particularly to an optimized process which permits operation at higher reducing temperatures with minimized problems of sinterization and agglomeration of iron ore particles. It is also an object of the present invention to provide a process wherein the required size of the reducing gas generating unit is reduced. Both objects are preferably achieved by means of injecting only natural gas, or a similar methane-containing gas into the cooling loop of the direct reduction process and venting a portion of the cooling gas from the cooling zone to the reducing zone (preferably, on the order of 1% to 2% of the methane content of the cooling gas in relation to the volume flow of the reducing gas).

Process for the direct reduction of iron ores

A double valve assembly for regulating the feed of particulate material to or from a pressure vessel comprises a valve casing containing a flow-regulating valve and pressure sealing valve in series. Particulate material is fed to the valve assembly through a feed tube located at the top of the casing. The flow-regulating valve comprises a dish-shaped valve member swingable from a first position wherein it confronts the bottom of the feed tube and blocks flow of material therethrough to a second position at one side of the feed tube. The bottom of the feed tube is constructed and arranged to guide the particulate material away from the second valve position and thereby facilitate swinging movement of the swingable member from its first to its second position.

Double valve assembly

Apparatus for breaking apart agglomerations of particulate matter flowing in a vessel (particularly useful ina pressurized moving-bed vertical-shaft reduction reactor for the production of sponge iron) is exemplified by an externally mounted hydraulic cylinder having access to the interior of said vessel through a probe port, the piston of said hydraulic cylinder being provided with a conical probe positioned so as to be normally retracted out from the interior of said vessel but extendable by said hydraulic cylinder into and across the interior of said vessel, preferably at the narrowed discharge portion thereof, whereby said probe is angled to extend downwardly in the direction of flow of said particulate matter as well as across said flow to engage and break up any agglomerations of particulate matter in its path. When used with a pressurized vessel, the probe may be uniquely adapted to function without reactor pressure loss by a housing for the probe, or alternatively for the entire probe and hydraulic cylinder, with said housing having open communication with said vessel, so as to minimize sealing problems with respect to the moving probe. In a reduction reactor, the probe is preferably mounted near the bottom of the cooling zone adjacent the narrowed discharge outlet so as normally to be retracted to avoid any obstruction of the uniform flow through the reactor, and yet be angled along and across the direction of flow to assist in the discharge and also intercept and break up agglomerations obstructing the narrowed discharge.

Apparatus for separating agglomerated particulate matter

A method for the gaseous reduction of iron ore to sponge iron in a vertical moving bed reactor having a reduction zone in the upper portion thereof and a cooling zone in the lower portion thereof which comprises using a coolant gas containing up to about 30% by volume of hydrocarbon, e.g., coke oven gas, and passing a mixture of the hydrocarbon-containing gas and steam through the cooling zone to cause the sponge iron therein to catalyze the conversion of the hydrocarbon/steam mixture to carbon monoxide and hydrogen.

Method of making sponge iron

A method of using coke oven gas, and more generally gaseous mixtures containing up to about 30% by volume of methane, for the direct gaseous reduction of iron ore in a vertical shaft, moving bed reactor. In addition to the usual reduction zone and cooling zone, the reactor is provided with an intermediate reforming zone. A hot mixture of coke oven gas and steam is fed to the intermediate zone and reduced ore therein catalyzes the conversion of the methane of the coke oven gas to carbon monoxide and hydrogen. The reformed gas flows upwardly into the reduction zone of the reactor.

Method of using a methane-containing gas for reducing iron ore

A method for the gaseous reduction of particulate ores to metals in a moving bed, vertical shaft reactor using a reducing gas externally supplied from a solid or liquid fossil fuel gasification unit. The reducing gas is reformed in a reforming zone located within the reactor and treated prior to injection into the reduction zone of the reactor. A portion of the reducing gas produced in a coal gasification unit may be used to cool the metal in the cooling zone of the reactor.

Method for the gaseous reduction of metal ores using reducing gas

Sponge iron is carburized in the cooling zone of a vertical shaft iron ore reduction reactor by causing a carbon-containing gas to circulate in a closed loop including the cooling zone of the reactor and an external conduit containing a quench cooler and a pump. Improved control of the carburization of the sponge iron is achieved by measuring the specific gravity of the circulating gas and using the measured specific gravity value as a control variable effectively to regulate the flow of make-up carbon-containing gas to the cooling loop.

Method for carburizing sponge iron

A method for inhibiting carburization of metal-bearing material in the reduction zone of a vertical shaft, moving bed reactor for the direct gaseous reduction of iron ore to sponge iron. Carburization within the reduction zone is decreased by regulating the water vapor content of the reducing gas in any of various ways, e.g., by adding water vapor in the form of steam to the reducing gas either before it enters the reduction zone, while it is within the reduction zone, or after it leaves the reduction zone or by recirculating a portion of the effluent gas from the reactor and cooling the recirculated gas to a predetermined extent.

Growing community of inventors

Monterrey, Mexico

Enrique R Martinez-Vera