The present invention relates to a process for the production of carbon dioxide and ammonia for the production of urea or ammonium carbamate from residual gases in the steel and metal industries, in particular basic oxygen furnace (BOF) gas and/or blast furnace (BF) gas. The process according to the invention comprises: (a) subjecting a mixture comprising (i) basic oxygen furnace gas and/or blast furnace gas and (ii) steam to a separation-enhanced water gas shift reaction to obtain a first product gas comprising H.sub.2 and N.sub.2 and a second product gas comprising CO.sub.2; (b) subjecting the first product gas originating from step (a) to NH.sub.3 synthesis to obtain a product gas comprising NH.sub.3; and (c) optionally subjecting at least part of the CO.sub.2 originating from step (a) and at least part of the NH.sub.3 originating from step (b) to the synthesis of urea or ammonium carbamate.

A plant complex for producing steel, having a blast furnace for producing pig iron; a converter steel works for producing crude steel; a gas pipeline system for gases that occur in the production of pig iron and/or the production of crude steel; a chemical plant and/or a biotechnology plant which are/is connected to the gas pipeline system, wherein the plant complex additionally includes a biogas plant which is connected to the gas pipeline system.

A plant complex for producing steel, having a blast furnace for producing pig iron; a converter steel works for producing crude steel; a gas pipeline system for gases that occur in the production of pig iron and/or the production of crude steel; a chemical plant and/or a biotechnology plant which are/is connected to the gas pipeline system, wherein the plant complex additionally includes a biogas plant which is connected to the gas pipeline system.

A plant complex for pig iron production may include a furnace and a furnace gas conduit system for a furnace gas quantity stream that comprises nitrogen, carbon monoxide, and carbon dioxide. The plant complex may also include a hydrogen source, an H.sub.2 gas conduit system for a hydrogen-containing gas quantity stream emitted from the hydrogen source, a mixing apparatus for establishing a mixed gas formed from the furnace gas stream and the hydrogen-containing gas quantity stream. The mixing apparatus may be connected to the furnace gas conduit system and to the H.sub.2 gas conduit system. The mixed gas established may have a stoichiometric mixing quotient formed from a dividend with a difference value between molar amounts of hydrogen as minuend and carbon dioxide as subtrahend and of a divisor with a sum value of molar amounts of carbon monoxide and carbon dioxide. The plant complex may also include a mixed gas conduit system and a chemical plant connected to the mixed gas conduit system.

A plant complex for pig iron production may include a furnace and a furnace gas conduit system for a furnace gas quantity stream that comprises nitrogen, carbon monoxide, and carbon dioxide. The plant complex may also include a hydrogen source, an H.sub.2 gas conduit system for a hydrogen-containing gas quantity stream emitted from the hydrogen source, a mixing apparatus for establishing a mixed gas formed from the furnace gas stream and the hydrogen-containing gas quantity stream. The mixing apparatus may be connected to the furnace gas conduit system and to the H.sub.2 gas conduit system. The mixed gas established may have a stoichiometric mixing quotient formed from a dividend with a difference value between molar amounts of hydrogen as minuend and carbon dioxide as subtrahend and of a divisor with a sum value of molar amounts of carbon monoxide and carbon dioxide. The plant complex may also include a mixed gas conduit system and a chemical plant connected to the mixed gas conduit system.

The present invention provides a novel method for supplying a reducing gas to the shaft part of a blast furnace with which a large amount of reducing gas containing hydrogen at a high concentration can be supplied to a deeper position in the blast furnace (location of the blast furnace closer to the center axis in the radial direction) and with which it is possible to reduce the total generated amount of CO.sub.2 of the CO.sub.2 amount that is reduced by conducting hydrogen smelting in the blast furnace and the CO.sub.2 amount that is generated during production of the reducing gas supplied to the blast furnace. The method for supplying a reducing gas to the shaft part of a blast furnace according to the present invention is characterized by reforming coke oven gas by increasing the temperature thereof to 1200 to 1800 C. in a reactor in which an oxygen-containing gas is supplied to preheated coke oven gas to generate reformed gas in which hydrogen gas is enriched; mixing the reformed gas with CO-containing gas in the reactor so that the hydrogen concentration of the reducing gas is adjusted to 15-35 vol % (wet); and supplying the resultant reducing gas to the shaft part of the blast furnace under a condition of a ratio of a flow rate of reducing gas blown into shaft part/flow rate of reducing gas blown into tuyere >0.42.

The present invention provides a novel method for supplying a reducing gas to the shaft part of a blast furnace with which a large amount of reducing gas containing hydrogen at a high concentration can be supplied to a deeper position in the blast furnace (location of the blast furnace closer to the center axis in the radial direction) and with which it is possible to reduce the total generated amount of CO.sub.2 of the CO.sub.2 amount that is reduced by conducting hydrogen smelting in the blast furnace and the CO.sub.2 amount that is generated during production of the reducing gas supplied to the blast furnace. The method for supplying a reducing gas to the shaft part of a blast furnace according to the present invention is characterized by reforming coke oven gas by increasing the temperature thereof to 1200 to 1800 C. in a reactor in which an oxygen-containing gas is supplied to preheated coke oven gas to generate reformed gas in which hydrogen gas is enriched; mixing the reformed gas with CO-containing gas in the reactor so that the hydrogen concentration of the reducing gas is adjusted to 15-35 vol % (wet); and supplying the resultant reducing gas to the shaft part of the blast furnace under a condition of a ratio of a flow rate of reducing gas blown into shaft part/flow rate of reducing gas blown into tuyere >0.42.

The invention relates to the use of pellets comprising one or more thermoplastic material(s) of more than 40%, based on the total dry weight of the pellets and one or more cellulosic material(s) of more than 20%, based on the total dry weight of the pellets, as a reducing agent in a process for making pig iron in a blast furnace. Said pellets can be provided in unground form, as a partial replacement of coke through the top of the blast furnace, or can be provided as reducing agent in the raceway in an amount of higher than 10 kg/ton iron.

The invention relates to the use of pellets comprising one or more thermoplastic material(s) of more than 40%, based on the total dry weight of the pellets and one or more cellulosic material(s) of more than 20%, based on the total dry weight of the pellets, as a reducing agent in a process for making pig iron in a blast furnace. Said pellets can be provided in unground form, as a partial replacement of coke through the top of the blast furnace, or can be provided as reducing agent in the raceway in an amount of higher than 10 kg/ton iron.

The invention relates to a plant complex for steel production comprising a blast furnace for producing pig iron, a converter steel mill for producing crude steel and a gas-conducting system for gases that occur when producing the pig iron and/or producing the crude steel. According to the invention, the plant complex additionally has a chemical plant or biotechnological plant, connected to the gas-conducting system, and also energy storage for covering at least part of the electricity demand of the plant complex. Also the subject of the invention is a method for operating the plant complex.