DRI (Direct Reduced Iron) production plant is an ironmaking unit, developed for the production of direct reduced iron. It is a gas-based shaft furnace process with a solid-state reduction process which reduces iron ore pellets or lump ore into DRI without their melting using reducing gases. The reducing agents, namely hydrogen (H2
) and carbon monoxide (CO), remove oxygen from the chemical structure of the iron ore pellets inside the shaft furnace at high temperatures. In order to make a high-quality DRI, a reducing gas rich in H2
and CO with specified molar ratio needs to be produced via reforming reaction of the natural gas with carbon dioxide and steam. Besides reforming reaction, many others take place inside the reformer tubes which is filled with catalysts. Regarding the severe conditions in the reformer, i.e. high temperature, low pressure, low steam to carbon ratio and high CO2
content in the reformer feedstock, two types of catalysts with different activity over an inert bed layer should be loaded to avoid catalyst deactivation with time. The top catalyst is the one with higher nickel content and activity, based on α-alumina, which is called highly active catalyst and the other with lower nickel oxide and activity on rugged magnesium oxide carrier is called the semi-active catalyst. KhTD proposes three catalyst codes, i.e. DRI-6HGRR-HA-01 for high active catalysts, DRI-1HRR-SA-01 for semi-active catalysts & DRI-1HR-I-01 for inert materials.
is a high active DRI reforming catalyst based on α-alumina carrier. This 6-hole ribbed ring-shaped catalyst containing high nickel oxide content loaded inside MIDREX reformer tubes as the major layer is considered for the complementary reforming of natural gas purposes along with semi-active catalyst.
: is a high active DRI reforming catalyst based on the α-alumina carrier with a different shape but the same formulation. This 10-hole flower shaped catalyst has the same nickel loading as “DRI-6HGRR-HA-01” but has lower pressure drop during the operation and higher geometric surface area. This catalyst is loaded inside reformer tubes in the top layer for the complementary reforming of hydrocarbons.
: A superior semi-active DRI reforming catalyst with lower nickel oxide content is based on basic magnesium oxide (MgO) carrier. Considering MgO carriers as a basic catalyst support, the coke formation during the reforming of natural gas feedstock will be significantly retarded compared to α-alumina carriers, especially when the amounts of steam to carbon ratio is substantially low contrary to carbon dioxide (CO2
) content which is significantly high, as can be seen in MIDREX reformers.
: is a robust and high strength inert ceramic support used for loading at the bottom section of MIDREX reformer tubes in order to pre-heat the feed gas to avoid coke formation at the beginning of the semi-active catalyst layer due to Boudouard or other unfavorable reactions.