A process for producing direct reduced iron with a hydrogen rich gas, utilizing a non-fired reducing gas heater such as an electric heater to heat the reducing gas to the temperatures sufficient for iron reduction, includes: providing a shaft furnace to reduce iron oxide with the hydrogen rich reducing gas; removing steam and particulates from the shaft furnace top gas with a scrubber; processing all or a portion of the scrubbed top gas in a gas separation unit such as a membrane and a PSA gas separation unit to create a hydrogen rich stream to be recycled back to the shaft furnace as the reducing agent, so that the hydrogen consumption can be reduced when non-fired reducing gas heater is applied.

The present disclosure provides a facility to produce direct reduced iron, which makes it possible to perform reforming and reduction and adjust the carbon amount in a product within a wide range without requiring an externally heating reformer and without causing the metal dusting problem in a circulating gas preheater and the problem of sintering each other or fusion between reduced iron, in a furnace. The facility to produce the direct reduced iron according to the present invention is equipped with a water content control device for controlling the water content in a gas discharged from a shaft-type reduction furnace, a first gas mixing device for mixing the gas from which a portion of water has been removed with an oxygen-containing gas and a hydrocarbon-containing gas to produce a mixed gas, and an auto-thermal reformer for reforming the mixed gas with its energy. The facility is also equipped with a cooling gas loop for circulating a cooling gas, wherein the cooling gas has a hydrocarbon concentration of 50% or more, and the cooling gas loop is equipped with a cooling gas after-cooler having a flow rate control function and capable of controlling the temperature of the cooling gas.

The invention relates to a process for direct reduction of iron ore to afford direct reduced iron, wherein the iron ore sequentially passes through a reduction zone for reducing the iron ore to direct reduced iron and a cooling zone for cooling the direct reduced iron, wherein in the reduction zone the iron ore is subjected to a flow of a reduction gas and wherein in the cooling zone the direct reduced iron is subjected to a flow of a cooling gas. The cooling gas in the cooling zone comprises H2 and CO2, wherein the ratio of the mole fractions of H2 to CO2 is greater than 1.8 and the mole fraction of CO2 is greater than 20 mol %.

Direct reduction process and plant for producing DRI comprising a reduction reactor and at least one reducing gas heater typically comprising a convective heating section and a radiant heating section for raising the reducing gas temperature to a level adequate for iron oxides reduction to metallic iron, typically above 850° C., wherein the reducing gas fed to the reduction reactor comprises a stream of reducing gas recycled from the reduction reactor and a make-up stream of coke oven gas containing carbon compounds which may form carbon deposits in the heating path of said heater, namely BTX and other complex carbon compounds. The heater is provided with means for feeding oxidizing agents, for example steam, steam and air and/or oxygen at predetermined heating tubes successively for eliminating the carbon deposits which may form inside the heating tubes of said heater without interrupting the operation of the plant. The make-up stream of cold COG can be combined with the recycled gas at a point in the gas heating path of the heater where the tubes have a skin wall temperature of at least 700° C., or when the mixture of recycled gas and COG is at a temperature above 700° C. for minimizing clogging or fouling of heating equipment.

The invention relates to a process for producing carburized directly reduced iron sponge from iron oxide material. Firstly, direct reduction is carried out by means of a reduction gas consisting at least predominantly of H.sub.2 and the carbon content in the iron sponge is then increased by means of a carburizing gas which is fed in, after which used carburizing gas is at least partly taken off while largely avoiding mixing with the reduction gas. The plant for producing carburized directly reduced iron sponge from iron oxide material comprises a reduction zone for directly reducing introduced iron oxide material to directly reduced product by means of reduction gas consisting predominantly of H.sub.2 and a reduction gas feed conduit opening into the reduction zone. It also comprises a carburization zone having a carburizing gas feed conduit opening into the carburization zone and a carburization offgas conduit.

A method and apparatus for producing direct reduced iron (DRI), including: generating a reducing gas in a coal gasifier using coal, oxygen, steam, and a first coke oven gas (COG) stream as inputs to the coal gasifier; and delivering the reducing gas to a shaft furnace and exposing iron ore agglomerates to the reducing gas to form metallic iron agglomerates. The method further includes delivering a second COG stream directly to the shaft furnace.

A direct reduction system and process for reducing a metal oxide to a metal, including and utilizing: a process gas line configured to deliver a portion of a process gas to a reformer operable for reforming the process gas to form a reformed gas; a bustle gas line configured to deliver the reformed gas to a shaft furnace as a bustle gas, wherein the shaft furnace is operable for reducing the metal oxide to the metal; and a direct recycle line including a direct recycle cooler configured to selectively deliver a portion of the process gas to the bustle gas line while circumventing the reformer, thereby selectively cooling and lowering the moisture content of the bustle gas delivered to the shaft furnace. Optionally, the direct reduction system further includes a reheat line configured to deliver a portion of the bustle gas to the shaft furnace as reheat gas.

A shaft furnace for producing metallic direct reduced iron (DRI) from iron-containing pellets or lumps and reducing gas disposed therein, including: a circumferential outer wall defining a top interior reducing zone, a middle interior transition zone, and a bottom interior cooling zone, wherein the iron-containing pellets or lumps travel downwards through the top interior reducing zone, the middle interior transition zone, and the bottom interior cooling zone as the iron-containing pellets or lumps encounter the upward-flowing reducing gas and one or more other gases; and a flow diverter disposed along a centerline of the circumferential outer wall including a convex-upwards upper tapering section disposed in the middle transition zone defined by the circumferential outer wall coupled to a convex-downwards lower tapering section disposed in the bottom cooling zone defined by the circumferential outer wall.

A direct reduction system and process for reducing a metal oxide to a metal, including and utilizing: a process gas line configured to deliver a portion of a process gas to a reformer operable for reforming the process gas to form a reformed gas; a bustle gas line configured to deliver the reformed gas to a shaft furnace as a bustle gas, wherein the shaft furnace is operable for reducing the metal oxide to the metal; and a direct recycle line including a direct recycle cooler configured to selectively deliver a portion of the process gas to the bustle gas line while circumventing the reformer, thereby selectively cooling and lowering the moisture content of the bustle gas delivered to the shaft furnace. Optionally, the direct reduction system further includes a reheat line configured to deliver a portion of the bustle gas to the shaft furnace as reheat gas.

The present disclosure provides a pre-reduced pellet preparation device and method based on grate-rotary kiln. The pre-reduced pellet preparation device comprises a grate-rotary kiln pellet oxidation system and a hydrogen-based shaft furnace reduction system. In the pre-reduced pellet preparation method, a roasting process and a reduction process for an iron-containing green pellet are organically combined, and a pellet cooling process after roasting and a heating process before pellet reduction are eliminated; physical heat of a roasted pellet is used to satisfy heat required in the heating and reduction processes; the technical problems of a low hydrogen utilization rate and high energy consumption of pellets in oxidative roasting and direct reduction processes in traditional direct reduction processes are solved; a reduced pellet having a certain metallization rate is obtained; the prepared pre-reduced pellet is used as blast furnace burden, such that blast furnace fuel consumption and carbon emission can be significantly reduced; the method is a new, low-carbon, and green pre-reduced pellet preparation process.