Abstract: A process and an apparatus for reducing charge materials containing iron ore or for producing pig iron or liquid primary steel products in a smelting unit are provided, the charge materials being at least partially reduced in at least one reduction unit by means of a reducing gas and optionally at least some of the at least partially reduced charge materials being melted in a smelting unit while supplying coal or coke and gas containing oxygen, while simultaneously forming the reducing gas, and the reducing gas or a reducing gas generated externally being supplied to the reduction unit. In the event of an interruption in the production of pig iron or primary steel products, the at least one reduction unit is emptied and the at least partially reduced charge materials are introduced into at least one vessel and kept under a non-oxidizing shielding gas atmosphere.

Abstract: An apparatus for producing a reducing gas for direct reduction iron-making includes an internal-heating type reformer for reforming a natural gas by adding steam and oxygen to the natural gas and by partially burning the natural gas to generate reducing gas containing hydrogen and carbon monoxide; a remover for removing carbon dioxide from exhaust gas generated in the direct reduction iron-making; and a line for recycling as the reducing gas the exhaust gas from which the carbon dioxide is removed by the remover.

Abstract: Methods and systems for the production of direct reduced iron, including: removing a top gas from a direct reduction furnace; carbon monoxide shifting the top gas using a carbon monoxide shift reactor to form a carbon monoxide shifted top gas having a reduced carbon monoxide content; adding one of a coal gas, a synthesis gas, and an export gas to at least a portion of the carbon monoxide shifted top gas to form a combined gas; removing carbon dioxide from the combined gas using a carbon dioxide removal unit to form a carbon dioxide lean combined gas; and providing the carbon dioxide lean combined gas to the direct reduction furnace as a reducing gas for producing direct reduced iron after heating to reduction temperature. Optionally, the method includes removing carbon dioxide from the top gas using a carbon dioxide removal unit prior to carbon monoxide shifting the top gas.

Abstract: Process gas purification device (2) for a melt reduction system (1) comprising at least one reduction reactor (3) and a melting gasification reactor (4), a first line system (5) for discharging a furnace gas (6) from the reduction reactor (3) and a second line system (7) for discharging a generator gas (8) from the melting gasification reactor (4) wherein both line systems (5,7) lead to a respective wet scrubbing system (11, 12). The furnace gas or generator gas flow can be throttled preferably by way of a control element (41) that varies a control gap (40) and the scrubber or cooling liquid (49) can be collected and drained. The first wet scrubber system (11) of the first line system (5) for routing the furnace gas (6) and the second Venturi scrubber system (12) of the second line system (7) for routing the generator gas (8) both discharge into a common mist elimination device (14).

Abstract: The present invention relates generally to a method and system for the supply of a continuous stream of hot direct reduced iron (HDRI) from a direct reduction (DR) shaft furnace or direct reduced iron (DRI) reheating furnace to a point outside of the DR shaft furnace or DRI reheating furnace where the HDRI stream is split into at least two HDRI streams. The first HDRI stream is sent continuously to a hot briquetting plant by gravity in a closed duct system. The second HDRI stream is sent continuously to an adjacent melting furnace also by gravity in a closed duct system, with a surge bin and feeders, or by a combination of gravity in a closed duct system, also with a surge bin and feeders, and a generally horizontal charge conveyor. Optionally, a third HDRI stream is employed to continuously feed multiple hot transport vessels.

Abstract: A direct reduction process for producing direct reduced iron (DRI) in a reduction reactor having a reduction zone for reducing iron-oxides-containing particles, such as iron ore pellets, to DRI by reaction of said iron oxides with a high temperature reducing gas, and a cooling zone for lowering the temperature of the DRI produced in said reduction zone, wherein a stream of cooling gas, usually natural gas, is circulated through said cooling zone, a portion of said cooling gas is withdrawn from the cooling zone, cooled and cleaned in a gas cooler and a portion of the cooled gas is recycled to said reduction zone by means of an ejector utilizing the high-pressure natural gas make-up feed as the ejector's motive fluid. Using an ejector for recycling the cooling gas instead of using a mechanical compressor provides significant savings in electricity and in capital, operational and maintenance costs.

Abstract: A method and apparatus for increasing hydrocarbons to a direct reduction shaft furnace while controlling the temperature uniformity of the center portion of the iron burden wherein the hydrocarbon gases used in direct reduction may be preheated, which increases the temperature of the hydrocarbon gases, and therefore increases the resultant temperature of the upflowing gases as it rises from the lower section of the furnace into the center of the burden. Alternatively, a portion of the upflowing gas may be removed before it enters the reduction zone of the furnace. The removed upflowing gas, known as hot bleed gas, may be ducted to the top gas scrubber of the furnace or may be mixed with the main reducing gas stream of the furnace for reintroduction to the furnace. Alternatively, hot reducing gas may be directly injected into the center portion of the burden, offsetting the cooling effect of the upflowing gas.

Abstract: The present invention relates to a pressure swing adsorption process for direct reduction of iron wherein a portion of spent reducing gas withdrawn from the direct reduction reactor is subjected to a PSA process for the removal of carbon dioxide from the spent reducing gas. An improved CO2-rejection method using an external natural gas purge stream after depressurization and before the product purge step is described. The PSA process comprises an external purge step with a non-absorbable gas, which surprisingly reduces the adsorbent regeneration requirements to maintain the selective adsorption of carbon dioxide from the spent reducing gas. The external natural gas purge results in a cleaner bed before the start of each adsorption cycle. Consequently, significantly more CO2 can be rejected and/or higher hydrogen and CO recoveries can be attained. The external purge stream is fully integrated into the DDRI production scheme.

Abstract: A method and apparatus for increasing hydrocarbons to a direct reduction shaft furnace while controlling the temperature uniformity of the center portion of the iron burden wherein the hydrocarbon gases used in direct reduction may be preheated, which increases the temperature of the hydrocarbon gases, and therefore increases the resultant temperature of the upflowing gases as it rises from the lower section of the furnace into the center of the burden. Alternatively, a portion of the upflowing gas may be removed before it enters the reduction zone of the furnace. The removed upflowing gas, known as hot bleed gas, may be ducted to the top gas scrubber of the furnace or may be mixed with the main reducing gas stream of the furnace for reintroduction to the furnace. Alternatively, hot reducing gas may be directly injected into the center portion of the burden, offsetting the cooling effect of the upflowing gas.

Abstract: An improved method and apparatus for increasing the productivity of a direct reduction process in which iron oxide is reduced to metallized iron by contact with hot reducing gas; comprising the steps of: a) providing a first hot reducing gas consisting essentially of CO and H2; b) providing additional reducing gas by reaction of a gaseous or liquid hydrocarbon fuel with oxygen; c) mixing the first hot reducing gas with the additional reducing gas to form a reducing gas mixture; d) enriching the reducing gas mixture by the addition of a gaseous or liquid hydrocarbon; e) injecting oxygen or oxygen-enriched air into the enriched mixture; and f) introducing the enriched mixture into an associated direct reduction furnace as reducing gas.

Abstract: Disclosed is a method for steel making which includes charging a direct reduction reactor (DRR) with iron ore from a charging system. The iron ore is reduced to hot direct reduced iron (DRI) in the DRR and discharged to rotary kiln(s). The rotary kiln(s) does not process the DRI, but transports the hot DRI to one or more electric arc furnaces (EAF). Top gas (i.e., spent reducing gas) is drawn off of a top section of the DRR. A portion of the top gas is used to pressurize the rotary kiln to prevent air from entering the rotary kiln. Another portion of the top gas flows to a pressure swing adsorber or a vacuum pressure swing adsorber (PSA/VPSA) for CO2 and H2O removal. A cool reducing gas exits the PSA/VPSA. A plasma torch burns natural gas and oxygen to form a hot reducing gas. The hot reducing gas is mixed with the cool reducing gas to form a final reducing gas. The final reducing gas is delivered to the DRR. Also disclosed is a mini-mill to perform the method of steel making.

Abstract: A method and apparatus for the production of prereduced iron ore, DRI, sponge iron or the like by the gaseous reduction of iron-oxide containing particles in a reduction system which comprises a preheating device for the iron ore particles. The preheating device preserves the strength of the iron ore particles through the reduction system by preheating the particles with non-reducing (or preferably oxidizing) gas, whereby the DRI or like material produced is stronger than if it were processed in a reduction reactor without said preheating device. The invention thereby avoids sticking and fines production problems which some iron ores cause in the reduction reactor. The preheating device also produces other advantages in the reduction system as, for example, that the reducing gas reaches a higher degree of oxidation in the reduction reactor whereby the productivity of the reduction system increases as a result of the decreased amount of reducing gas as well as the decreased residence time required.

Abstract: Method for the direct reduction of mineral iron inside a vertical reduction furnace (10) of the type with a gravitational load, wherein the reducing gas flows in counter-flow with respect to the material introduced into the furnace, comprising the following steps: the mineral iron is fed from above into the furnace (10), a mixture of high temperature gas consisting of reducing gas based on H2 and CO is injected, and the reduced mineral is removed from the furnace (10). The mixture of gas is introduced into at least a zone (14) of the furnace (10) and consists of the process gas, which emerges from the same furnace, and of additional gas arriving from an outside reforming circuit.

Abstract: A process and apparatus for continuously reducing carbon monoxide (CO), uncombined free hydrogen (H2) and volatile hydrocarbons (VOC's) in molten metal refining vessel off-gases without forming undesirable oxides of nitrogen. Off-gases are directed to a reaction chamber wherein CO, H2 and VOC's are oxidized at a controlled temperature and with a controlled quantity of O2 So as to realize substantially total oxidation of gases present with minimized formation of oxides of nitrogen. Volume and energy of treated gases directed for baghouse treatment are reduced in comparison with prior practice.

Abstract: Method for the direct reduction of mineral iron inside a vertical reduction furnace (10) of the type with a gravitational load, wherein the reduction gas flows in counter-flow with respect to the material introduced into the furnace, comprising the following steps: the mineral iron is fed from above into the furnace (10), a mixture of high temperature gas consisting of reducing gas based on H2 and CO is injected, and the reduced mineral is removed from the furnace (10), the mixture of gas being introduced in at least two zones (12, 14) of the furnace (10) arranged one above the other so as to achieve, in a controlled manner, a first stage of pre-heating and pre-reduction in the upper part (12) of the furnace (10) and a second stage of final reduction in the lower part (14) of the furnace (10).

Abstract: A process to optimize the reduction process with a given quality of ore. The reduction gas 7 is analyzed by means of gas sensor 1 and is separated into two partial flows. The throughput of the partial flow which is oxidized is regulated by a regulation valve 3 and is then sent to the burner 4 where it is oxidized. The other partial flow of the reduction gas is regulated by a regulation valve 2 according to the required amount of gas in the shaft and is thereafter brought to the required temperature in the heat exchanger 11 and mixed with the oxidized partial flow of the reduction gas. The gas components are determined by a gas sensor 13 and, when necessary, a gas delivery 14 is adjusted according to mathematical formulations. This makes it possible to run the reduction process in the direction of its stoichiomeric optimum using a given quality of ore.

Abstract: A method and apparatus for increasing the productivity of an existing direct reduction iron (DRI) plant without increasing its reformer capacity existing in the plant. This object is achieved by not only recycling some effluent gas of the reduction reactor to the gas reformer (with natural gas or the like added with an oxidant as make up gas), but also recycling an additional portion of the effluent gas with added natural gas and an oxygen containing stream directly to the reducing gas stream exiting the reformer prior to or as part of its introduction to the reduction reactor, thereby providing additional reducing agents and increasing the reducing capacity of the plant. The oxygen containing stream is preferably added to the recycled reducing gas without preheating. Any excess or purged effluent gas is as usual burned as fuel.

Abstract: An improved method and apparatus for forming metallized iron by direct reduction of particulate iron oxide is disclosed. Spent reducing gas is recycled from the reduction furnace through a cooler-scrubber and a catalyst-containing stoichiometric gas reformer. Upon removing the process gas from the cooler-scrubber, it is contacted with a chlorine dioxide spray, then compressed and cooled, the sulfur compound removed, and the process gas recycled either into the furnace cooling zone, or directly into the reformer, or divided and directed into both uses. Thus, most of the sulfur containing components of the spent reducing gas are removed, thereby reducing the sulfur contamination of the gas reformer catalyst. Reducing sulfur contamination of the gas reformer catalyst improves the overall efficiency of the direct reduction process. Either high sulfur ores, or high sulfur process gas, or both can be utilized in the invented process.

Abstract: A method and apparatus for the production of iron carbide in a shaft furnace, by reacting a carbon containing reducing gas as the process gas with particulate metal oxide material for an extended residence time at low temperature.

Abstract: A method for modifying existing direct reduction processes and retrofitting existing direct reduction facilities so as to increase the capacity of the facilities without the need for increasing the capacity of external reformers associated with the existing facilities comprises mixing preheated air with the reformed reducing gas produced in the external reformers and containing said mixture with excess natural gas in a reduction-reaction zone of the direct reduction reactor.

Abstract: An improved method and apparatus for forming metallized iron by direct reduction of particulate iron oxide is disclosed. Spent reducing gas is recycled from the reduction furnace through a cooler-scrubber and a catalyst-containing stoichiometric gas reformer. Upon removing the process gas from the cooler-scrubber, it is contacted with a chlorine dioxide spray, then compressed and cooled, the sulfur compound removed, and the process gas recycled either into the furnace cooling zone, or directly into the reformer, or divided and directed into both uses. Thus, most of the sulfur containing components of the spent reducing gas are removed, thereby reducing the sulfur contamination of the gas reformer catalyst. Reducing sulfur contamination of the gas reformer catalyst improves the overall efficiency of the direct reduction process.