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US20090133535A1 - Process for production of elemental iron - Google Patents

Process for production of elemental iron Download PDF

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US20090133535A1
US20090133535A1 US12/275,041 US27504108A US2009133535A1 US 20090133535 A1 US20090133535 A1 US 20090133535A1 US 27504108 A US27504108 A US 27504108A US 2009133535 A1 US2009133535 A1 US 2009133535A1
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gas
stream
process according
reducing gas
reducing
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Gijsbert Jan Van Heeringen
Hendrik Jan Van Der Ploeg
Cornelis Jacobus Smit
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Shell USA Inc
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Assigned to SHELL OIL COMPANY reassignment SHELL OIL COMPANY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: VAN DER PLOEG, HENDRIK JAN, SMIT, CORNELIS JACOBUS, VAN HEERINGEN, GIJSBERT JAN
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
    • C01B3/52—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with liquids; Regeneration of used liquids
    • C01B3/54—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with liquids; Regeneration of used liquids including a catalytic reaction
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
    • C01B3/52—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with liquids; Regeneration of used liquids
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
    • C10K1/00—Purifying combustible gases containing carbon monoxide
    • C10K1/34—Purifying combustible gases containing carbon monoxide by catalytic conversion of impurities to more readily removable materials
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0073—Selection or treatment of the reducing gases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0415—Purification by absorption in liquids
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0465—Composition of the impurity
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0465—Composition of the impurity
    • C01B2203/0475—Composition of the impurity the impurity being carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0465—Composition of the impurity
    • C01B2203/0485—Composition of the impurity the impurity being a sulfur compound
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0465—Composition of the impurity
    • C01B2203/0495—Composition of the impurity the impurity being water
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/80—Aspect of integrated processes for the production of hydrogen or synthesis gas not covered by groups C01B2203/02 - C01B2203/1695
    • C01B2203/86—Carbon dioxide sequestration
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0959—Oxygen
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0969—Carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/20—Increasing the gas reduction potential of recycled exhaust gases
    • C21B2100/28—Increasing the gas reduction potential of recycled exhaust gases by separation
    • C21B2100/282—Increasing the gas reduction potential of recycled exhaust gases by separation of carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/40—Gas purification of exhaust gases to be recirculated or used in other metallurgical processes
    • C21B2100/42—Sulphur removal
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/60—Process control or energy utilisation in the manufacture of iron or steel
    • C21B2100/62—Energy conversion other than by heat exchange, e.g. by use of exhaust gas in energy production
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C2100/00—Exhaust gas
    • C21C2100/06—Energy from waste gas used in other processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/122—Reduction of greenhouse gas [GHG] emissions by capturing or storing CO2
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P30/00—Technologies relating to oil refining and petrochemical industry

Definitions

  • the invention is directed to a process to prepare elemental iron by contacting an iron ore feed with a reducing gas comprising synthesis gas, wherein the reducing gas is prepared by a partial oxidation process.
  • Direct reduction of iron generates metallic iron in a solid form by removing oxygen from the iron ore by using a reduction gas that can be provided from the synthesis gas obtained by gasification of carbonaceous feedstock.
  • Industrially applied DRI processes include MIDREX, HyL and FINMET, as described in “Development of Reduction Process for the Steel Production” by M. Gojic and S. Kozuh, Kem. Ind. 55 (1) 1-10 (2006).
  • EP-A-0916739 describes a process wherein the reducing gas for the DRI process is obtained by gasification of a coal slurry.
  • the reducing gas fed to the DRI includes a recycle gas stream that has exited the DRI, and wherein acid gases have been removed from the recycle gas stream.
  • U.S. Pat. No. 5,871,560 describes a process wherein synthesis gas is mixed with an off-gas produced in a DRI process to be used as a reduction gas and wherein H 2 S is fed to the reducing gas.
  • step (a) partially oxidizing a mixture comprising a sulphur containing solid carbonaceous fuel and gaseous CO 2 as carrier medium with oxygen, by supplying an oxygen containing gas and the solid carbonaceous fuel to a burner, thereby obtaining a gas comprising H 2 , CO, CO 2 and H 2 S;
  • step (b) removing CO 2 and H 2 S from the gas obtained in step (a) to obtain the reducing gas comprising H 2 and CO and a first stream comprising CO 2 and H 2 S;
  • a further advantage of the present invention is that, for a given amount of carbonaceous fuel to be partially oxidised in the gasification reactor, a smaller reactor volume can be used, resulting in lower equipment expenses, as compared to a situation wherein no CO 2 is present in step (a).
  • a further advantage is that the removal of CO 2 and H 2 S is performed in one step, namely step (b), while in the process of U.S. Pat. No. 2,740,706 this removal takes place in two steps.
  • FIG. 1 schematically shows a process scheme for a process according to the present invention.
  • the iron ore feed is usually in the form of pellets or in the lump form or a combination of the two.
  • the iron ore is supplied to a heated furnace or to a set of reactors through which it descends by gravity at superatmospheric pressure, e.g., 1.5-12 bar.
  • Iron ore feed is reduced in the said furnace or set of reactors by the action of counterflowing reducing gas that has high H 2 and CO contents.
  • Process specifics of the DRI processes are described for example in “Kirk-Othmer Encyclopedia of Chemical Technology”, fourth edition, volume 14, John Wiley & Sons, 1985, pages 855-872.
  • the reducing gas is used to remove oxygen from the iron oxide comprised within the iron ore feed.
  • the reducing process can be illustrated by the following reaction, where H 2 O and CO 2 are obtained as by-products:
  • the reducing gas has H 2 /CO ratio of at least 0.5. It is also preferred that the reducing gas has a “gas quality” of at least 10.
  • the gas quality is defined as a ratio of reductants to oxidants, as demonstrated by the following equation:
  • Iron obtained from the DRI process is cooled and carbonized by means of the counterflowing gasses in the lower portion of a shaft furnace according to the following reaction:
  • the off-gas obtained by the DRI process is the spent reducing gas exiting the furnace.
  • the off-gas can be cleaned by scrubbing and CO 2 removal and is preferably recycled to be used as the reducing gas.
  • Preferably the off-gas is treated before the re-use as reducing gas to satisfy the requirement for reducing gas as described above.
  • step (a) of the process according to the invention a mixture comprising a sulphur containing solid carbonaceous fuel and CO 2 with oxygen containing gas is partially oxidized, thereby obtaining a gas comprising H 2 , CO, CO 2 and H 2 S.
  • the partial oxidation may be performed by any process known.
  • the partial oxidation is performed by means of the so-called entrained-flow gasification process as described in “Gasification” by C. Higman and M. van der Burgt, 2003, Elsevier Science, Chapter 5.3, pages 109-128.
  • step (a) is performed in an entrained-flow gasifier process wherein the reaction between the mixture of carbonaceous fuel and CO 2 with oxygen containing gas takes place in a gasification reactor provided with one or more burners.
  • an oxygen containing gas and a solid carbonaceous fuel are supplied to a burner.
  • CO 2 is used as carrier medium to transport the fuel to the burner.
  • One or more burners can be provided in the gasification reactor.
  • the burner can be a single burner directed downward at the top of a vertically elongated reactor.
  • the gasification reactor will have substantially horizontal firing burners in diametrically opposing positions.
  • the burner is preferably a co-annular burner with a passage for an oxygen containing gas and a passage for the fuel and the carrier gas. Partial oxidation of the carbonaceous fuel occurs at a relatively high temperature in the range of 1000° C. to 2000° C. and at a pressure in a range of from about 1-70 bar. Preferably the pressure is between 10 and 70 bar, more preferably between 30 and 60 bar.
  • the gas is cooled with either direct quenching with water, direct quenching with the off-gas, direct quenching with the part of the gas obtained in either steps (a) or (b), by indirect heat exchange against evaporating water or combination of such cooling steps.
  • Slag and other molten solids are suitably discharged from the gasification reactor at the lower end of the said reactor.
  • solid carbonaceous fuel may be any carbonaceous fuel in solid form.
  • solid carbonaceous fuels are coal, coke from coal, petroleum coke, soot, biomass and particulate solids derived from oil shale, tar sands and pitch.
  • the solid carbonaceous fuel is chosen from the group of coal, petroleum coke, peat and solid biomass.
  • Coal is particularly preferred, and may be of any type and sulphur content, including lignite, sub-bituminous, bituminous and anthracite. Although in many DRI processes natural gas is used as a fuel, coal is an interesting choice for a fuel source because of its abundance. Coal is preferably supplied to the burner in form of fine particulates.
  • fine particulates is intended to include at least pulverized particulates having a particle size distribution so that at least about 90% by weight of the material is less than 90 ⁇ m and moisture content is typically between 2 and 12% by weight, and preferably less than about 8%, more preferably less than 5% by weight.
  • coal is supplied in admixture with CO 2 as a carrier medium.
  • Gaseous CO 2 containing carrier medium contains preferably at least 80%, more preferably at least 95% CO 2 .
  • CO 2 can be separated from the reducing gas and from the off-gas of the DRI process. It has been found that by using CO 2 as obtained in step (c) in step (a), as the carrier medium, a more efficient process is obtained.
  • the CO 2 containing carrier gas supplied in step (a) is supplied to the burner at a velocity of less than 20 m/s, preferably from 5 to 15 m/s, more preferably from 7 to 12 m/s. Further it is preferred that the CO 2 and the carbonaceous fuel are supplied at a density of from 300 to 600 kg/m 3 , preferably from 350 to 500 kg/m 3 , more preferably from 375 to 475 kg/m 3 .
  • the weight ratio of CO 2 to the carbonaceous fuel in step (a) is in the range from 0.12-0.49, preferably below 0.40, more preferably below 0.30, even more preferably below 0.20 and most preferably between 0.12-0.20 on a dry basis.
  • step a) comprises partially oxidizing a mixture consisting of a sulphur containing solid carbonaceous fuel and CO 2 with oxygen containing gas.
  • the oxygen containing gas comprises substantially pure O 2 or air. Preferably it contains at least 90% by volume oxygen, with nitrogen, carbon dioxide and argon being permissible as impurities. Substantially pure oxygen is preferred, such as prepared by an air separation unit (ASU). Steam may be present in the oxygen containing gas as supplied to the burner to act as moderator gas. The ratio between oxygen and steam is preferably from 0 to 0.3 parts by volume of steam per part by volume of oxygen. When the downstream DRI process requires a high CO to H 2 ratio it is advantageous to use CO 2 instead of steam as a moderator gas. This CO 2 is preferably CO 2 as obtained in step (c). A mixture of the fuel and oxygen from the oxygen containing stream is then reacted in a reaction zone in the gasification reactor.
  • ASU air separation unit
  • the gaseous stream obtained in step (a) comprises mainly H 2 and CO, which are the main components of the synthesis gas, and can further comprise other components such as CO 2 , H 2 S, HCN and COS.
  • the gaseous stream obtained in step (a) suitably comprises from 1 to 10 mol % CO 2 , preferably from 4.5 to 7.5 mol % CO 2 on a dry basis when performing the process according to the present invention.
  • the gaseous stream obtained in step (a) is preferably subjected to a dry solids removal and wet scrubbing.
  • the dry solids removal unit may be of any type, including the cyclone type.
  • the dry solid material is discharged from the dry solids removal unit to be further processed prior to disposal.
  • the gaseous stream obtained in step (a) is contacted with a scrubbing liquid in a soot scrubber.
  • the gaseous stream exiting the gasifier is generally at elevated temperature and at elevated pressure.
  • the scrubbing step in the soot scrubber is preferably performed at elevated temperature and/or at elevated pressure.
  • the temperature at which the reducing gas is contacted with scrubbing liquid is in the range of from 120 to 160° C., more preferably from 130 to 150° C.
  • the pressure at which the gaseous stream obtained in step (a) is contacted with scrubbing liquid is in the range of from 20 to 80 bara, more preferably from 20 to 60 bara.
  • the process further comprises step (b) of removing CO 2 and H 2 S from the gas obtained in step (a) thereby obtaining the reducing gas comprising H 2 and CO and a first stream comprising CO 2 and H 2 S.
  • CO 2 recovery system Removing CO 2 and H 2 S is performed in a, hereafter referred to, CO 2 recovery system.
  • the CO 2 recovery system is preferably a combined CO 2 /H 2 S removal system.
  • CO 2 /H 2 S removal is performed by absorption using so-called physical and/or chemical solvent process.
  • the CO 2 recovery is performed on the gaseous stream obtained in step (a).
  • the off-gas of the DRI contacting process is suitably also subjected to the same or a different CO 2 recovery system to obtain a recycle reducing gas comprising CO and H 2 and a second stream comprising CO 2 and possibly H 2 S.
  • the second stream and the first stream are the same and will be referred to as the first stream.
  • step (a) It is preferred to remove at least 80 vol %, preferably at least 90 vol %, more preferably at least 95 vol % and at most 99.5 vol %, of the CO 2 present in the gaseous stream obtained in step (a).
  • Absorption processes are characterized by washing the synthesis gas with a liquid solvent, which selectively removes the acid components (mainly CO 2 and H 2 S) from the gas.
  • the laden solvent is regenerated, releasing the acid components and recirculated to the absorber.
  • the washing or absorption process takes place in a column, which is usually fitted with for example packing or trays.
  • On an industrial scale there are chiefly two categories of absorbent solvents, depending on the mechanism to absorb the acidic components: chemical solvents and physical solvents. Reference is made to the absorption process as described in chapters 8.2.1 and 8.2.2 of “Gasification” (already referred to), page 298-309, and Perry, Chemical Engineerings' Handbook, Chapter 14, Gas Absorption.
  • Chemical solvents which have proved to be industrially useful are primary, secondary and/or tertiary alkanolamines.
  • the most frequently used amines are derived from ethanolamine, especially monoethanol amine (MEA), diethanolamine (DEA), triethanolamine (TEA), diisopropanolamine (DIPA) and methyldiethanolamine (MDEA).
  • Physical solvents which have proved to be industrially suitable are cyclo-tetramethylenesulfone and its derivatives, aliphatic acid amides, N-methylpyrrolidone, N-alkylated pyrrolidones and the corresponding piperidones, methanol, ethanol and mixtures of dialkylethers of polyethylene glycols.
  • a well-known commercial process uses an aqueous mixture of a chemical solvent, especially DIPA and/or MDEA, and a physical solvent, especially cyclotetramethylene-sulfone also referred to as sulfolane.
  • a chemical solvent especially DIPA and/or MDEA
  • a physical solvent especially cyclotetramethylene-sulfone also referred to as sulfolane.
  • Such systems show good absorption capacity and good selectivity against moderate investment costs and operational costs. They perform very well at high pressures, especially between 20 and 90 bara.
  • the solvent comprises one or more compounds selected from the group of N-methylpyrrolidone (NMP), dimethyl ether of polyethylene glycol (DMPEG), methanol or an amine such as di-isopropanol amine (DIPA) or mixtures of amines with sulfolane. More preferably, the solvent comprises an amine and sulfolane.
  • NMP N-methylpyrrolidone
  • DMPEG dimethyl ether of polyethylene glycol
  • DIPA di-isopropanol amine
  • the solvent comprises an amine and sulfolane.
  • step (b) comprises one or more further removal systems that may be guard or scrubbing units, either as back-up or support to the CO 2 /H 2 S removal system.
  • further removal systems are aimed at removing HCN and COS or other contaminants such as NH 3 , H 2 S, metals, carbonyls, hydrides or other trace contaminants which may be comprised in the gas obtained in step (a).
  • step (b) is performed by at least two steps wherein in a first step the gas obtained in step (a) is contacted with the HCN/COS hydrolysis catalyst to convert HCN to NH 3 and COS to H 2 S, followed by removal of water and ammonia from the gas by cooling and/or scrubbing, and in a second step the gas obtained in said first step is contacted with a suitable solvent, which is selective for absorbing CO 2 and H 2 S as described above.
  • the process of contacting the gas obtained in step (a) with the HCN/COS hydrolysis catalyst to convert HCN to NH 3 and COS to H 2 S takes place by catalytic hydrolysis in the hydrolysis unit.
  • a suitable hydrolysis step are disclosed in WO-A-04105922.
  • the hydrolysis zone can be a gas/solid contactor, preferably a fixed bed reactor.
  • Catalysts for the hydrolysis of HCN and COS are known to those skilled in the art and include for example TiO 2 -based catalysts or catalysts based on alumina and/or chromium-oxide.
  • Preferred catalysts are TiO 2 -based catalysts.
  • the process further comprises step (c) of reducing the content of H 2 S in the first stream comprising CO 2 and H 2 S obtained in step (b).
  • the CO 2 as obtained in step (c) has a sulphur content lower than 10 ppmv, more preferably between 5 and 10 ppmv.
  • Step (c) is performed by means of a liquid redox type process.
  • step (c) is performed by liquid redox type process by contacting the stream of CO 2 and H 2 S obtained in step (b) with an aqueous reactant solution comprising iron (III) chelate of an organic acid or complex reactant system to produce elemental sulphur which is recovered as a by-product of the present process either prior to or subsequent to regeneration of the reactant, as described in for example “Gas Purification” by A. Kohl and R. Nielsen, Gulf Publishing Company, fifth edition, pages 670-840, and more specifically pages 803-840.
  • the reduction of H 2 S content in step (c) can also be performed on a mixture of the first and second stream comprising CO 2 and H 2 S.
  • the process according to the invention further includes step (d) wherein at least part of the CO 2 obtained in step (c) is recycled to step (a).
  • the CO 2 that is recycled to step (a) is isolated from the first and optional second stream comprising CO 2 and H 2 S.
  • the reducing gas obtained in step (b) is directed to an expander wherein the pressure of the reducing gas is reduced and power is generated.
  • the reducing gas is then heated in a gas heater before entering the furnace of the DRI process where it is contacted with iron ore feed to produce iron and the off-gas.
  • the off-gas of the DRI contacting process can be subjected to the CO 2 recovery as described above, thereby obtaining a recycle reducing gas comprising CO and H 2 and a second stream comprising CO 2 and H 2 S.
  • the recycle reducing gas comprising CO and H 2 can be recycled to the furnace of the DRI process.
  • the CO 2 from the first and second streams comprising CO 2 and H 2 S is preferably used in step (a) as a carrier medium to carry the coal to the burner.
  • Excess CO 2 is preferably stored in subsurface reservoirs or more preferably a part of the CO 2 as obtained in step (c) is used for one of the processes comprising enhanced oil recovery, CO 2 sequestration or coal bed methane extraction.
  • a part of the CO 2 can be injected into the subterranean zone to obtain a desired pressure in said subterranean zone such to enhance the recovery of a hydrocarbon containing stream as produced from said subterranean zone.
  • a part of the reducing gas obtained in step (c) is preferably used as a fuel in a gas turbine to generate power.
  • a sulphur containing solid carbonaceous fuel ( 1 ), preferably coal as fine particulates, is mixed with the CO 2 containing carrier gas ( 2 ) and fed to a burner of a gasification reactor ( 4 ) where it is contacted with an oxygen containing gas ( 3 ) to obtain the reducing gas comprising H 2 and CO ( 5 ) and slag ( 4 a ).
  • the reducing gas ( 5 ) is treated in a dry solids removal unit ( 6 ).
  • the dry solid material is discharged from the dry-solids removal unit ( 6 ) via line ( 6 a ).
  • the cleaned reducing gas ( 13 ) is expanded in an expander ( 14 ) whereby power ( 15 ) is produced to be used in the current process or in a separate process.
  • the reducing gas exiting the expander via line ( 16 ) is further heated in a heater ( 17 ) and is directed as a stream ( 18 ) to a DRI furnace ( 19 ) where it is used as a reducing gas to be contacted with the iron ore ( 20 ).
  • the resulting iron is discharged via stream ( 21 ).
  • the off-gas ( 22 ) of the DRI furnace ( 19 ) is directed to a CO 2 removal system ( 23 ) wherein CO 2 is separated thereby obtaining a second stream comprising CO 2 and H 2 S ( 24 ) and a recycle reducing gas comprising CO and H 2 ( 35 ).
  • the recycle reducing gas comprising CO and H 2 ( 35 ) is recycled to the DRI furnace ( 19 ) via heater ( 17 ), by combining stream ( 35 ) with stream ( 16 ).
  • the said stream ( 24 ) is directed as stream ( 25 ) to a liquid redox process type unit ( 10 ) where it joins the first stream comprising CO 2 and H 2 S ( 9 ) exiting the CO 2 /H 2 S removal system ( 8 ).
  • Gas treatment can take place in separate systems ( 8 ) and ( 23 ), or it can take place in a single system.
  • the sulphur obtained in the liquid redox process type unit ( 10 ) is discharged via stream ( 11 ) while the CO 2 exits the liquid redox process type unit ( 10 ) as stream ( 29 ).
  • a part ( 30 ) of stream ( 29 ) can be directed to any other suitable process where CO 2 is used via the stream ( 32 ).
  • Another part of the stream ( 29 ) is used as carrier gas ( 2 ) for carrying the carbonaceous feed ( 1 ) to the gasifier ( 4 ).
  • the gas stream ( 24 ) may by-pass the liquid redox process type unit ( 10 ) as stream ( 31 ). This stream may also find use as the above stream ( 32 ) or as carrier gas ( 2 ).

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Industrial Gases (AREA)
  • Manufacture Of Iron (AREA)
  • Gas Separation By Absorption (AREA)
US12/275,041 2007-11-20 2008-11-20 Process for production of elemental iron Abandoned US20090133535A1 (en)

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EP07121142 2007-11-20
EP07121142.9 2007-11-20
US99116207P 2007-11-29 2007-11-29
US12/275,041 US20090133535A1 (en) 2007-11-20 2008-11-20 Process for production of elemental iron

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EP (1) EP2209922A2 (fr)
JP (1) JP2011503363A (fr)
AU (1) AU2008327918A1 (fr)
WO (1) WO2009065843A2 (fr)
ZA (1) ZA201002945B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100050812A1 (en) * 2008-08-21 2010-03-04 Gijsbert Jan Van Heeringen Process for Production of Elemental Iron
US20150306541A1 (en) * 2014-03-21 2015-10-29 Joseph Naumovitz Methods for treating furnace offgas
CN108014598A (zh) * 2016-11-02 2018-05-11 中国石油化工股份有限公司 一种除去碎煤低温甲醇洗尾气中非甲烷烃及回收c2+烃的系统及方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT508522B1 (de) 2009-07-31 2011-04-15 Siemens Vai Metals Tech Gmbh Reformergasbasiertes reduktionsverfahren mit vermindertem nox-ausstoss
US8518356B2 (en) 2010-07-27 2013-08-27 Air Products And Chemicals, Inc. Method and apparatus for adjustably treating a sour gas

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US5871560A (en) * 1994-06-23 1999-02-16 Voest-Alpine Industrieanlagenbau Gmbh Process and plant for the direct reduction of iron-oxide-containing materials
US6149859A (en) * 1997-11-03 2000-11-21 Texaco Inc. Gasification plant for direct reduction reactors

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US2740706A (en) * 1951-10-10 1956-04-03 Texaco Development Corp Method of reducing metal oxides
BE791243A (fr) * 1971-12-23 1973-05-10 Texaco Development Corp Procede de production d'un melange gazeux reducteur
US3868817A (en) * 1973-12-27 1975-03-04 Texaco Inc Gas turbine process utilizing purified fuel gas

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USH825H (en) * 1988-05-20 1990-10-02 Exxon Production Research Company Process for conditioning a high carbon dioxide content natural gas stream for gas sweetening
US5871560A (en) * 1994-06-23 1999-02-16 Voest-Alpine Industrieanlagenbau Gmbh Process and plant for the direct reduction of iron-oxide-containing materials
US6149859A (en) * 1997-11-03 2000-11-21 Texaco Inc. Gasification plant for direct reduction reactors

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100050812A1 (en) * 2008-08-21 2010-03-04 Gijsbert Jan Van Heeringen Process for Production of Elemental Iron
US7931731B2 (en) * 2008-08-21 2011-04-26 Shell Oil Company Process for production of elemental iron
US20150306541A1 (en) * 2014-03-21 2015-10-29 Joseph Naumovitz Methods for treating furnace offgas
CN108014598A (zh) * 2016-11-02 2018-05-11 中国石油化工股份有限公司 一种除去碎煤低温甲醇洗尾气中非甲烷烃及回收c2+烃的系统及方法

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WO2009065843A3 (fr) 2009-07-09
WO2009065843A2 (fr) 2009-05-28
EP2209922A2 (fr) 2010-07-28
ZA201002945B (en) 2010-12-29
AU2008327918A1 (en) 2009-05-28
JP2011503363A (ja) 2011-01-27

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