Conical-bottomed fluidized bed reactor for iron metallization using hot hydrogen

Abstract

A system for producing metallic iron from ore using hot hydrogen. The system comprises a conical-bottomed fluidized bed reactor, wherein the conical bottom comprises a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor. Also, the system comprises heating means for heating hydrogen, which is suitably selected to allow for a decrease or elimination of greenhouse gas (GHG) emissions. The system further comprises means for recycling unreacted hot hydrogen and re-use. Moreover, the system comprises means for pre-heating the ore.

Description

CONICAL-BOTTOMED FLUIDIZED BED REACTOR FOR IRON METALLIZATION USING HOT HYDROGENCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 476,467 filed December 21 , 2022; the content of which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates generally to the production of metallic iron from ore such as ilmenite ore. More specifically, the invention relates to a conical-bottomed fluidized bed reactor for producing metallic iron using hot hydrogen. Production of the hot hydrogen uses a technology adapted to allow for a decrease or elimination of greenhouse gas emissions. The production system according to the invention allows for recycling of unreacted hot hydrogen and re-use.BACKGROUND OF THE INVENTION

[0003] There is a desire to decrease or even eliminate greenhouse gas (GHG) emissions upon ilmenite smelting to produce titania slag and liquid iron.

[0004] The current ilmenite smelting uses coal to reduce iron oxides in ilmenite ore from “Fe2O3” to “FeO” in slag and “Fe” in liquid iron.

[0005] Use of coal for the smelting process produces a smelter gas that typically comprises high contents of CO and H2as main components.

[0006] The smelter gas can be used to pre-reduce the iron oxides in the ilmenite ore from “Fe2O3” up to “FeO” before the ore is smelted in an electric arc furnace, which decreases the specific consumption of coal (kg-coal / kg-ore), thereby decreasing GHG emissions.

[0007] The pre-reduction from “Fe2O3” to “FeO” by smelter gas can be limited to high quality ilmenite ores due to the availability of smelter gas and the slow reduction kinetics.

[0008] It is known in the art that the reduction from “Fe2O3” to “FeO” in ilmenite ore by using H2can be achieved and even pushed further to reduce “FeO” to metallic iron in ilmenite ore and thereby achieve a significant decrease in GHG emissions.

[0009] Thermodynamic calculations and experiments have confirmed the minimum specific hydrogen consumption (Nm3-H2per ton of ore) at different temperatures.

[0010] Use of hydrogen for the reduction of iron oxides in ilmenite ore in a fluidized bed requires sufficiently high reaction temperature.

[0011] However, the current technology designs do not allow to continue the reaction and achieve metallization since the reactor cannot maintain the required reaction temperature.

[0012] The inventors are aware of the following document: Briggs and Sacco J. Mater. Res. (1991) 6(3), 574-584. The document relates to the production of oxygen from ilmenite. The process is conducted in a thermogravimetric reactor.

[0013] There is a need for apparatus, processes, and systems for producing metallic iron from ore, which are efficient, environmentally friendly, and cost-effective.SUMMARY OF THE INVENTION

[0014] The inventors have designed and developed a system comprising a conical- bottomed fluidized bed reactor for producing metallic iron from ore using hot hydrogen. The conical bottom comprises a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor. The system also comprises heating means for heating hydrogen, which is suitably selected to allow for a decrease or elimination of greenhouse gas (GHG) emissions. The system according to the invention further comprises means for recycling unreacted hot hydrogen and re-use.

[0015] In embodiments of the invention, the plurality of nozzles is provided in rows located at different heights around the circumference of the cone. A number of rows may be two, three, or more as desired.

[0016] In embodiments of the invention, the production system comprises means for heating hydrogen. Such heating means may comprise a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof. Such heating means may also involve electricity.

[0017] In embodiments of the invention, the reactor comprises one or more pipes for removing unreacted hot hydrogen after the production process is conducted. Theunreacted hot hydrogen may further be subjected to a recycling process which involves cooling and condensation. The recycled hydrogen may further be re-used in the system.

[0018] In embodiments of the invention, the reduction reaction of ore using hot hydrogen as described herein may be partial. Accordingly, an iron material may be obtained, which comprises Fe2O3, FeO, and / or metallic iron. In embodiments of the invention, the reduction reaction is repeated a number of times until completion.

[0019] In embodiments of the invention, the reactor comprises at least one solid charge / discharge pipe located at a circumference thereof.

[0020] The invention thus provides the following in accordance with aspects thereof.(1) A conical-bottomed fluidized bed reactor for reducing ore using hot hydrogen to obtain an iron material, comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor.(2) The conical-bottomed fluidized bed reactor according to (1) above, wherein the iron material comprises Fe2O3, FeO, and / or metallic iron; preferably the iron material comprises FeO and metallic iron; preferably the iron material comprises FeO; preferably the iron material comprises metallic iron.(3) A conical-bottomed fluidized bed reactor for producing metallic iron from ore using hot hydrogen, comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor.(4) The conical-bottomed fluidized bed reactor according to any one of (1) to (3) above, wherein the plurality of nozzles is provided in rows at different heights around the circumference of the cone; preferably a number of rows is two, three, or more.(5) The conical-bottomed fluidized bed reactor according to any one of (1) to (4) above, wherein the conical bottom presents an angle of about 65 degrees from the vertical.(6) The conical-bottomed fluidized bed reactor according to any one of (1) to (5) above, further comprising one or more pipes located at a top end of the reactor for removing unreacted hot hydrogen.(7) The conical-bottomed fluidized bed reactor according to any one of (1) to (6) above, further comprising at least one solid charge / discharge pipe located at a circumference of the reactor; preferably at a location different from the conical bottom.(8) A system for producing metallic iron from ore using hot hydrogen, comprising: a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor; and heating means for heating hydrogen, wherein the heating means comprises a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof; preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature.(9) A system for producing metallic iron from ore using hot hydrogen, comprising: a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor; and heating means for heating hydrogen, wherein the heating means involves electricity.(10) A system for producing metallic iron from ore using hot hydrogen, comprising: a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and one or more pipes located at a top end of the reactor for removing unreacted hot hydrogen; heating means for heating hydrogen, comprising a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof; preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature; and means for recycling the unreacted hot hydrogen for re-use.(1 1) A system for producing metallic iron from ore using hot hydrogen, comprising: a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and one or more pipes located at a top end of the reactor for removing unreacted hot hydrogen; heating means for heating hydrogen, wherein the heating means involves electricity; and means for recycling the unreacted hot hydrogen for re-use.(12) The system according to (10) or (11) above, wherein the means for recycling comprises cooling means and condensation means.(13) The system according to any one of (8) to (12), further comprising means for preheating the ore prior to introduction into the reactor.(14) A process for producing metallic iron from ore using hot hydrogen, comprising: introducing ore into a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone; injecting the hot hydrogen into the reactor through the plurality of nozzles; and subjecting the ore to a reduction reaction thereby producing the metallic iron.(15) A process for producing metallic iron from ore using hot hydrogen, comprising: introducing ore into a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone, and one or more pipes located at a top end of the reactor; injecting the hot hydrogen into the reactor through the plurality of nozzles; subjecting the ore to a reduction reaction thereby producing the metallic iron; and removing unreacted hot hydrogen from the reactor through the one or more pipes; optionally the last three steps of the process are repeated a number of time until the reaction is completed.(16) A process for producing metallic iron from ore using hot hydrogen, comprising: introducing ore into a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone, and one or more pipes located at a top end of the reactor; injecting the hot hydrogen into the reactor through the plurality of nozzles; subjecting the ore to a reduction reaction thereby producing the metallic iron; removing unreacted hot hydrogen from the reactor through the one or more pipes; and subjecting the unreacted hot hydrogen to a recycling process; optionally the last four steps of the process are repeated a number of time until the reaction is completed.(17) The process according to (16) above, further comprising heating the recycled unreacted hydrogen then re-introducing same into the reactor through the nozzles; preferably an amount of water in the recycled hydrogen is less than an amount of water in the unreacted hot hydrogen; preferably an amount of water in the recycled hydrogen is below 0.3% or less.(18) The process according to any one of (14) to (17) above, wherein the hot hydrogen is obtained using heating means comprising a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof; preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature.(19) The process according to any one of (14) to (17) above, wherein the hot hydrogen is obtained using heating means involving electricity.(20) The process according to any one of (14) to (17) above, wherein a temperature of the hot hydrogen is about 900°C to about 1300°C; preferably at about 1000°C to about 1200°C.(21) The process according to any one of (14) to (20) above, wherein the ore is preheated prior to introduction into the reactor.(22) Use of hot hydrogen in a process for producing metallic iron from ore, comprising using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor.(23) Use of hot hydrogen in a process for producing metallic iron from ore, wherein the use comprises using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and wherein the use comprises use of heating means comprising a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof; preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature.(24) Use of hot hydrogen in a process for producing metallic iron from ore, wherein the use comprises using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hothydrogen into the reactor, and wherein the use comprises use of heating means involving electricity.(25) Use of hot hydrogen in a process for producing metallic iron from ore, wherein the use comprises using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and wherein the use comprises removing unreacted hot hydrogen from the reactor and recycling the unreacted hot hydrogen for re-use.(26) A plant for producing of metallic iron from ore using hot hydrogen, the plant embodying the conical-bottomed fluidized bed reactor as defined in any one of (1) to (7) above, the system as defined in any one of (8) to (12) above, the process as defined in any one of (14) to (21) above, and / or the use as defined in any one of (22) to (25) above.(27) The conical-bottomed fluidized bed reactor as defined in any one of (1) to (7) above, the system as defined in any one of (8) to (12) above, the process as defined in any one of (14) to (21) above, the use as defined in any one of (22) to (25) above, or the plant as defined in (26), wherein ore is ilmenite ore or any other ore material comprising iron oxides such as hematite, magnetite, etc.

[0021] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0023] In the appended drawings:

[0024] Figure 1 : Conical bottom of hydrogen distributor (1A); conical-bottomed fluidized bed reactor (1 B)

[0025] Figure 2: Velocity distribution along the cone

[0026] Figure 3: Cold modeling half reactor and computational particle fluid dynamics (CPFD) modeling for hydrodynamics of gas distribution

[0027] Figure 4: Bottom of the hydrogen distributor easily replaceable in the plant

[0028] Figure 5: Cooling and condensation of hydrogen to remove water - Option 1

[0029] Figure 6: Cooling and condensation of hydrogen to remove water - Option 2

[0030] Figure 7: Hydrogen efficiency for ilmenite reduction

[0031] Figure 8: Plasma torch results

[0032] Figure 9: Block flow diagram outlining aspects of the invention.DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0033] Before the present invention is further described, it is to be understood that the invention is not limited to the particular embodiments described below, as variations of these embodiments may be made and still fall within the scope of the appended claims. It is also to be understood that the terminology employed is for the purpose of describing particular embodiments; and is not intended to be limiting. Instead, the scope of the present invention will be established by the appended claims.

[0034] In order to provide a clear and consistent understanding of the terms used in the present specification, a number of definitions are provided below. Moreover, unless defined otherwise, all technical and scientific terms as used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure pertains.

[0035] Use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and / or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one”. Similarly, the word “another” may mean at least a second or more.

[0036] As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “include” and “includes”) or “containing” (and any form of containing, such as “contain” and “contains”), are inclusive or open-ended and do not exclude additional, unrecited elements or process steps.

[0037] As used herein, the term “ore” refers to any material containing iron, iron-titanium oxides, iron oxides (hematite, magnetite, ilmenite, etc.), or the like. The material may be a naturally occurring material or a material which has been artificially produced. The term also refers to ilmenite ore.

[0038] The inventors have designed and developed a system for producing metallic iron from ore using hot hydrogen. The system comprises a conical-bottomed fluidized bed reactor, wherein the conical bottom comprises a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor. Also, the system comprises heating means for heating hydrogen, which is suitably selected to allow for a decrease or elimination of greenhouse gas (GHG) emissions. The system according to the invention further comprises means for recycling unreacted hot hydrogen and re-use. Moreover, the system comprises means for pre-heating the ore.

[0039] Various aspect and components of embodiments of the invention are described in detail below.Fluidized bed reactor

[0040] The inventors have designed a fluidized bed reactor. A demonstration plant is under construction which will include the fluidized bed reactor that will use hydrogen to reduce the iron in ilmenite ore. The reactor will operate at a temperature over 800°C and to supply the heat required for the reactor bed, hot hydrogen at a temperature over 900°C will be used. It is desired to decrease or eliminate emission of greenhouse gases, so preferably combustion of fossil fuels to provide the heat will be avoided.

[0041] Hot hydrogen will be used to heat the bed as well as to reduce the ilmenite. Heating means for heating hydrogen will use electricity to reduce greenhouse gas generation. In embodiments of the inventions, the heating means may comprise a plasma torch and / or a Kanthal pipe heater. As will be understood by a skilled person, heating process involving the plasma torch heats the hydrogen externally; and the Kanthal electric heaters which have good high-temperature stability can be incorporated into more traditional equipment. Also, as will be understood by a skilled person, any other suitable heating means may be used, preferably such heating means allows for a decrease or elimination of greenhouse gas emission. After heating, the hot hydrogen needs to be injected into the fluidized bed.

[0042] Injecting hot hydrogen into a typical cylindrical fluidized bed may present some challenges. If hydrogen is injected at the bottom of the bed, the distributor will haveto be able to distribute at a temperature of 1000°C (or more), which can be challenging. For example, if the hot hydrogen is injected into the solids at the wall of a large cylindrical reactor, the hydrogen will not contact the solids efficiently at the center of the reactor.

[0043] Therefore, the inventors have designed a conical-bottomed fluidized bed with hydrogen injection via nozzles in the cone. This geometrical configuration has the advantage that the hydrogen can be injected at different radial locations in the cone so its gas / solids contacting will be better than for a fully-cylindrical reactor. The conical bottom also promotes better axial mixing of solids. Accordingly, the invention provides for a reactor with a conical bottom with hydrogen injection in the cone. Computational Particle Fluid Dynamics (CPFD) simulation and pilot laboratory tests and analysis of the design were made. Details on the design are described herein below.Design of a conical-bottomed, fluidized bed reactor

[0044] The demonstration plant according to the invention will be 1.9 m (6.23 ft) in diameter. It will operate at a temperature of approximately 850°C (1562°F). The reduction of the iron in the demonstration plant is an endothermic reaction, so heat must be supplied to the reactor for the reaction to proceed. The heat will be supplied by hot hydrogen at approximately 1000 to 1050°C (1832 to 1922°F). Also, ore will be pre-heated. The hot hydrogen will be supplied to the reducer from either a plasma torch or from electrically heated pipes with the electrical heating elements made of a Kanthal alloy. The invention provides for the use of a conical-bottomed fluidized reactor to reduce the iron in the ilmenite ore. The hot hydrogen will be added to the reactor at different heights on the cone using nozzles. Three different levels of nozzles will be used.

[0045] There are at least two primary reasons for using a conical bottom for the demonstration plant. One reason is to be able to introduce gas at different radial positions in the cone so that the gas will be distributed better in the bed. A traditional distributor used for fully-cylindrical vessels may present some challenges in this case because the hydrogen feed gas is at a temperature of 1000 to 1050°C and typical gas distributors may not withstand such high temperatures. However, introducing hot hydrogen at the wall of the conical bottom is feasible and will allow radial distribution of gas into the bed. The second reason for using a cone is to enhance the solids motion in the bed.With typical flat-bottomed vessels, the solids at the wall of the vessel near the bottom may remain sluggish or stagnant. With a conical bottom, the solids flow downward along the wall and do not remain stagnant at the corner where the cone meets the cylindrical portion of the vessel. In addition, the conical section promotes gas bubble flow in the core region of the reactor.

[0046] There are several operating and material parameters that were used to design the reactor. These are as follows:• The total pressure at the bottom of the bed should preferably be no more than 100 kPag (14.5 psig) at the lower nozzles to avoid the need for a more expensive pressure vessel design. The maximum pressure allowed before the restriction orifices added for good distribution of the gas at each nozzle level should preferably be between 115 to 120 kPag (16.7 to 17.4 psig).• The height of the bed above the lowest nozzle location should preferably be 3.9 m (12.8 ft).• The particle density of the solids is approximately 4493 kg / m3(280.8 lb / ft3).• The estimated bulk density is 2500 kg / m3(156.3 lb / ft3).• The fluidized bed density of the solids is about 2000 kg / m3(125 lb / ft3).• The inlet hydrogen flow to the bed is about 1013 Nm3 / h (35,758.9 Stdft3 / hr).• The solids flow rate into the reactor is about 613 kg / h (1348.6 Ib / hr).• The solids flow rate out of the reactor is about 561 kg / h (1234.2 Ib / hr).• The pressure in the freeboard of the reactor can range between about 6 and 14 kPa (0.87 to 2 psig). It was assumed to be 10 kPag (1.45 psig) for the calculations.

[0047] The particle size distribution of the solids in the reactor is shown below in Table 1 below.Table 1. Particle size distribution of bed solids

[0048] The median diameter (Dp50) of this particle size distribution is 167.3 microns. A particle size of 168 microns was used in calculations which required an average particle size.

[0049] Gas compositions at the inlet and outlet of the bed are shown in Table 2 below.Table 2. Inlet and outlet gas compositions

[0050] The molecular weights of the inlet and outlet gas streams are about 3.42 and 4.53 Ib / lbmol, respectively.

[0051] Fluidization tests on the material at ambient conditions were conducted. Minimum fluidization velocity (Umf) for this material was approximately 0.04 m / s (0.131 ft / s). Using the Wen & Yu correlation to calculate the minimum fluidization velocity gave a velocity of 0.122 ft / s (0.037 m / s), relatively close to the measured Umf.

[0052] This Umf calculation was made for a particle size of 168 microns (the median size of the particle size distribution in Table 1). A material having an average particle size of168 microns is a Geldart Group B material. There is another fluidization velocity that is important for Geldart Group B materials called the complete fluidization velocity (Ucf). When the average particle size in the mixture is used to describe the velocity required to completely fluidize a material with a wide particle size distribution, often the larger materials are not fluidized because the estimated gas velocity is too low. To ensure that the largest particle will be fluidized, the minimum fluidization velocity correlation should be applied to the largest particle in the size distribution. Applying the Wen & Yu correlation to the largest particle size (500 microns) in the mixture gives a complete fluidization velocity of 0.952 ft / s at ambient conditions. Using the Wen & Yu correlation to calculate Umf and Ucf at reactor conditions gave velocities of 0.093 and 0.808 ft / s (0.028 and 0.246 m / s), respectively. In embodiments of the invention, the bed is operated at a velocity above the complete fluidization velocity to have solids well mixed in the reactor.

[0053] The gas densities and viscosities used to calculate Umf and Ucf are shown in Table 3 along with the minimum and complete fluidization velocities for ambient and reactor conditions of 850°C and 10 kPa (1562°F and 1.45 psig).Table 3. Parameters used to calculate Umf and Ucf at ambient and reactor conditions

[0054] The volumetric flow rate into the bed is 1013 Nm3 / hr (35,758.9 Std ft3 / hr). At reactor conditions in the freeboard, the volumetric flow rate is 131 ,943.2 ft3 / hr (3737.8 m3 / hr). For an area of 30.52 ft2at the top of the bed, the gas velocity through the bed is 1 .2 ft / s (0.366 m / s). This is greater than the complete fluidization velocity at the top of the bed (0.808 ft / s). The ratio of the gas velocity at the top of the bed to Ucf is 1 .2 / 0.808 = 1 .49, so the mixing in the bed should be sufficient.

[0055] A drawing of the proposed conical bottom for this bed is shown in Figure 1A. The cone (10) has an angle of about 65 degrees from the vertical. This angle was selected because it is known to have operated satisfactorily in other conical-bottom beds, and because it did not experience as much refractory erosion as other angles.

[0056] There is a 20-in diameter bottom “floor” of the conical bottom and there are three rows of nozzles (12) located around the circumference of the cone. The centerline of the lowest nozzle ring is 6 inches (15 cm) above the “floor”. The other two levels of nozzles are located 1.465 ft (44.65 cm) apart vertically as shown in Figure 1A. There are four nozzles at the lowest nozzle level, 6 at the middle level and 12 at the highest level making a total of 22 nozzles in the cone. Each refractory-lined nozzle is 1 .5 inches in diameter and is angled downward from the horizontal. The velocity through the nozzles varies from 96.1 ft / s at the lower nozzles to 106 ft / s at the top nozzles as shown in Table 4 below. The conical-bottomed fluidized bed reactor (14) according to the invention is illustrated in Figure 1 B.Table 4. Nozzle parameters

[0057] The approximate gas velocity distribution across the conical bottom is shown in Figure 2. The distribution is fairly equal across the height with an average value of approximately 1 .18 ft / s. The red dotted line in the figure is the calculated value of Ucf forthe material at reactor conditions. The velocity along the cone height is substantially greater than Ucf at all points along the height of the cone.

[0058] There is a restriction orifice before each nozzle at each level to distribute the gas flow equally through the nozzles at each level. The normal criterion for designing the orifice diameter for the restriction orifices is when the pressure drop through the orifice equals 30% of the pressure drop across the bed from the nozzle level in the cone to the top of the bed. The estimated pressure at the nozzles, the pressure drop across the restriction orifices and the pressure at the entrance to the orifices are shown in Table 5 below. For an orifice pressure drop equal to 0.3 times the pressure drops across the bed, the pressure at the entrance to the restriction orifice is 109.56 kPa, while the pressure at the lower nozzles is 12.56 psig (86.6 kPag). The pressure at the lower nozzles is lower than the maximum pressure allowed at this point (100 kPag).Table 5. Nozzle Conditions and Parameters for orifice pressure drop = 0.3 times the pressure drop across the bed.

[0059] In embodiments of the invention, another restriction orifice may be placed before the restriction orifices described above. In these embodiments, the pressure drop across these orifices may be 7 kPa. This would make the pressure before the nozzles (109.4 + 7 = 116.4 kPag). This would place the maximum pressure allowed within the 115 to 120 kPag allowed, but it is close to the maximum.

[0060] Therefore, several options were investigated to reduce the maximum pressure before the restriction orifices. One option was to reduce the pressure in the freeboard from 10 kPag to 6 kPag. Another option was to reduce the pressure at the bottom of the bed by reducing the height of the bed slightly. Athird option was to eliminate pressure drop requirement at the lower nozzles. The results obtained when applying these options are shown in Table 6 below. The different options are in the columns of the table.

[0061] Option 1 shown in Column 1 is for the conditions shown in Table 5 but using a freeboard pressure of 6 kPag instead of 10 kPag. In this option, the pressure drop across the restriction orifices was essentially 30% of the pressure drop across the bed above these nozzles. In Option 2 shown in Column 2, the bed height was lowered by 0.5 ft (0.15 m). For this case, the pressure drop across the restriction orifices was essentially 30% of the pressure drop across the bed. This option appears to be feasible if the fluidized bed can be lowered by 0.5 ft. Option 3 is to not use the orifices at the lower nozzles. In this option the restriction orifices would be the only orifices used to distribute the gas to the nozzles. These options are shown in Table 6 below and the calculations for the freeboard pressure of 6 kPag is called Case 1. For Option 1 in Table 6, the pressure at the lower nozzles was 82.6 kPag (12 psig). The pressure at the entrance to the restriction orifices was 105 kPag (15.2 psig), and the pressure at the entrance to the distribution nozzles was 112 kPag (16.2 psig). The pressure drop across the restriction orifices was 29.2% of the pressure drop across the bed.

[0062] For Option 2 where the bed height was lowered by 0.5 ft (0.15 m) , the values for the pressure at the lower nozzles, the pressure at the entrance to the restriction orifices and the pressure at the entrance to the nozzles were 79.6, 102, and 109 kPag (11.6, 14.8, and 15.8 psig), respectively.Similarly, for Case 3 with no pressure drop allowed for the distribution nozzles, these values were 82.6, 105, and 105 kPag (12, 15.2, and 15.2 kPag), respectively. The pressure drop across the distribution nozzles was the same as for Option 1 . All of these cases would appear to be feasible, and the total pressure at the entrance to the nozzles is less than the 115 to 120 kPag specified.Table 6. Options for reducing the inlet pressure to the reactor for a freeboard pressure of 6 kPag (0.87 psig)Case 1Option 1 Option 2 Option 3Pressure in freeboard, kPag 6 6 6Pressure in freeboard, psig 0.87 0.87 0.87Bed density, kg / m32000 2000 2000Bed density, lb / ft3125 125 125Bed density, psi / ft 0.868 0.868 0.868Height of bed above lower nozzles, m 3.9 3.75 3.9 Height of bed above lower nozzles, ft 12.8 12.3 12.8 Pressure drop across bed, psi 11.11 10.7 11.11 Pressure drop across bed, kPa 76.6 73.6 76.6 Pressure at lower nozzles, psig 11.98 11.6 11.98 Pressure at lower nozzles, kPag 82.6 79.6 82.6 Required pressure drop, kPa 7 7 0 Required pressure drop, psi 1.02 1.02 0Remaining pressure drop for restriction orifices, psi 3.25 3.24 3.25 Remaining pressure drop for restriction orifice, kPa 22.4 22.4 22.4 % of bed pressure drop across restriction orifices, % 29.3 30.4 29.3 Pressure before restriction orifices, kPag 105 102 105 Pressure before distribution orifices, kPag 112 109 105

[0063] However, it would appearthat 6 kPag in the freeboard of the reactor may not be a sufficient pressure to force the gas through the downstream equipment. Therefore, a freeboard pressure of 14 kPag (2.03 psig) may be used to design the restriction orifices. The three different options shown in Table 6 above were then re-examined / recalculated for the higher freeboard pressure of 14 kPag. The results of this analysis (called Case 2) are shown in Table 7 below.

[0064] Options 1 , 2, and 3 for Case 2 that are shown in Table 7 below were recalculated using 14 kPag (2.03 psig) as the pressure in the freeboard. For Option 1 , the calculations were made forthe case when the pressure drop across the restriction orifices was 25.4% of the pressure drop across the fluidized bed. The pressure at the lower nozzles was 90.6 kPag (13.1 psig) for this case, and the pressure at the entrance to the restriction orifices was 110 kPag (15.95 psig). The pressure at the entrance to the distribution nozzles was 117 kPag (16.97 psig). The value of 117 kPag is within the specified value but is a fairly high pressure. Option 2 is better in this regard and has a pressureof 87.6 kPag (12.7 psig) at the lower nozzles. The pressure at the entrance to the restriction nozzles is 107 kPag (15.5 psig) and the pressure at the entrance to the distribution nozzles would be 1 14 kPag (16.5 psig). This appears to be better than Option 1 , and the pressure drop across the restriction orifices is still satisfactory at 26.3%.

[0065] For Option 3 (no pressure drop across the lower distribution nozzles), the pressure at the lower nozzles is the same as for Option 1 at 90.6 kPag (13.1 psig). The pressure at the entrance to the restriction orifices is 110 kPag (15.95 psig) but because no distribution orifice is used, the pressure at the entrance to the orifices is the same as it is for the restriction orifices at 110 kPag (15.95 psig). The pressure drop across the restriction orifices is still satisfactory at 25.4%. For Case 2 which is the most likely Case for option as it gives more flexibility, Options 2 and 3 seem best, with Option 3 being better than Option 2 because it has the lowest pressure at the entrance due to no distribution orifice.Table 7. Options for reducing the inlet pressure to the reactor for a freeboard pressure of 14 kPag (2.03 psig)Case 2Option 1 Option 2 Option 3Pressure in freeboard, kPag 14 14 14Pressure in freeboard, psig 2.03 2.03 2.03Bed density, kg / m32000 2000 2000Bed density, lb / ft3125 125 125Bed density, psi / ft 0.868 0.868 0.868Height of bed above lower nozzles, m 3.9 3.75 3.9Height of bed above lower nozzles, ft 12.8 12.3 12.8Pressure drop across bed, psi 1 1.1 1 10.7 1 1.1 1Pressure drop across bed, kPa 76.6 73.6 76.6Pressure at lower nozzles, psig 13.1 12.7 13.1Pressure at lower nozzles, kPag 90.6 87.6 90.6Required pressure drop, kPa 7 7 0Required pressure drop, psi 1.02 1.02 0Remaining pressure drop for restriction orifices, psi 2.82 2.81 2.82Remaining pressure drop for restriction orifice, kPa 19.4.4 19.4 19.4% of bed pressure drop across restriction orifices, % 25.4 26.3 25.4Pressure before restriction orifices, kPag 1 10 1 107 110Pressure before distribution orifices, kPag 1 17 1 14 110

[0066] A 4-in diameter discharge / drain nozzle is shown at the bottom of the conical bottom.Solids will flow out of the reactor at a rate of 561 kg / hr (1234.2 Ib / hr).

[0067] In embodiments of the invention, it is not necessary that the drain / discharge pipe be placed at the bottom of the bed as shown in Figure 1. The solids discharge pipe may also be placed anywhere along the height of the bed if space below the bottom of the bed is at a premium.Summary of aspects of embodiments of the fluidized bed reactor

[0068] A conical bottom for the fluidized bed demonstration plant reducer reactor was designed.

[0069] The conical bottom contains three levels of 1 .5-in diameter nozzles with 4 nozzles in the bottom ring, 6 in the middle ring, and 12 in the upper ring.

[0070] The bottom, middle, and top nozzles have an exit velocity of 96.1 , 100.8, and 106.0 ft / s, respectively.

[0071] It appears that in order to minimize the pressure at the entrance to the orifices at the bottom and at the same time provide sufficient pressure in the freeboard to force gas flow through the equipment downstream of the process, it is preferable to operate at 14 kPag in the reactor freeboard and to use Option 3 shown in Table 7. This option has no distribution orifice at the level of the lower nozzles.

[0072] A 4-in diameter bottom drain / discharge pipe was added to the bed. Because the solids flow rate is small, it may be necessary to let the solids flow into the reactor for some time and then discharge the same amount of solids over a smaller time period. This pipe may also be added to the side of the bed if space below the bottom of the reactor is at a premium.Hot hydrogen production

[0073] In embodiments of the invention, plasma torch is used to heat hydrogen. A hydrogen distributor has a tempered bottom. The hydrogen distributor has a number of injectors and downward angles, and the bottom can be easily replaced in the plant; see Figure 3 and Figure 4.

[0074] Experiments were conducted on the use of plasma torch to heat hydrogen. More specifically, a plasma with pure hydrogen was generated, which was subsequently used to heat a flow of hydrogen. The plasma torch (model MARC11 L) was installed in a mixing chamber to heat a stream of fresh or recycled hydrogen. Steam of pure hydrogen wassent to the torch to generate the plasma, while two other streams were sent to a shroud to contain the heat from the plasma and to a mixing chamber. The mixing chamber outlet stream temperature was controlled by the torch power and the flow rates of hydrogen. The stream of hot hydrogen was subsequently sent to a further section for post treatment. Some results obtained during these tests are illustrated in Figure 8.Hydrogen recycling

[0075] After the process is conducted, hot hydrogen is removed from the fluidized bed reactor and subjected to cooling and condensation to remove water. Cooling and condensation may be conducted as known in the art using water. Two of such options are illustrated in Figure 5 (Option 1) and Figure 6 (Option 2).

[0076] In embodiments of the invention, it is desired to bring the water content in recycled H2below 0.3% or less.

[0077] The inventors conducted theoretical and experimental studies on the metallization of iron-titanium oxides by hydrogen. The results obtained are illustrated in Figure 7 and outlined in Table 8 below. As can be seen, they suggested a relatively low hydrogen utility as a reductant, which was confirmed by the internal and external experimental studies. These studies outline the importance of the aspect of the invention wherein unreacted hot hydrogen is removed from the reactor and recycled for re-use.Table 8. Hydrogen efficiency for ilmenite reductionTemperature (°C) Theory Experiment Theory Experiment850 18.2 18.5 - 19.0 5.5% 5.2 - 5.4%1000 11.6 13.3 - 14.1 8.6% 7.1 - 7.5%

[0078] Other aspects of the invention including a pre-heating of the ore are outlined in Figure 9. The process has three main steps, each with a fluid bed reactor. The ore is fed to a first fluid bed reactor where the ore is heated with a fuel gas, while air is used as a fluidizing gas. The off gas is treated in a gas scrubber before being sent to the atmosphere. The second fluid bed reactor, which is fluidized with a reduction gas such as hydrogen, performs the reduction reaction. The fluidization gas is heated in the plasma torch before being sent to the reactor’s conical bottom. The off gas is treated in a scrubberbefore being sent to the hydrogen recycling step. The final step has a fluid bed used to cool the ore before storage, while the off gas is once again sent to a scrubber before release to the atmosphere. The pre-reduction would decrease the amount of energy for the following smelting or remelting process, which leads to the reduction of greenhouse gas (GHG) emissions.

[0079] As will be understood by a skilled person, although pure hydrogen is used the embodiments of the inventions described herein, any other suitable hydrogen-rich source may also be used, preferably a hydrogen-rich source with sufficiently low H2O content.

[0080] As will be understood by a skilled person, the reduction reaction of ore using hot hydrogen as described herein may be partial. Accordingly, an iron material may be obtained, which comprises Fe2O3, FeO, and / or metallic iron. In embodiments of the invention, the iron material comprises a mixture of FeO and metallic iron. In embodiments of the invention, the iron material comprises FeO only. In embodiments of the invention, the iron material comprises a mixture metallic iron (Fe) only.

[0081] As described herein above and a will be understood by a skilled person, the process of the invention comprises the steps of: (a) introducing ore into a conical- bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone, and one or more pipes located at a top end of the reactor; (b) injecting the hot hydrogen into the reactor through the plurality of nozzles; (c) subjecting the ore to a reduction reaction thereby producing the metallic iron; and (d) removing unreacted hot hydrogen from the reactor through the one or more pipes. In embodiments of the invention, the last three steps of the process, namely, steps (b) through (d) may be repeated a number of time until the reduction reaction is completed. In embodiments of the invention, each time, the unreacted hot hydrogen is subjected to a recycling process.

[0082] As will be understood by a skilled person, the invention relates to a system and to a plant embodying the conical-bottomed fluidized bed reactor for reducing ore using hot hydrogen and the process according to the invention.

[0083] As will be understood by a skilled person, other variations and combinations may be made to the various embodiments of the invention as described herein above.

[0084] While the present disclosure has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations including suchdepartures from the present disclosure as come within known or customary practice within the art and as may be applied to the essential features hereinbefore set forth, and as follows in the scope of the appended claims. Features which are described in the context of separate aspects and embodiments of the invention may be used together and / or be interchangeable. Similarly, features described in the context of a single embodiment may also be provided separately or in any suitable sub-combination.

[0085] The present disclosure refers to a number of documents, the content of which is herein incorporated by reference in their entirety.

[0086] The scope of the claims should not be limited by the preferred embodiments set forth herein above; but should be given the broadest interpretation consistent with the description as a whole.

Claims

CLAIMS:

1. A conical-bottomed fluidized bed reactor for reducing ore using hot hydrogen to obtain an iron material, comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor.

2. The conical-bottomed fluidized bed reactor according to claim 1 , wherein the iron material comprises Fe2O3, FeO, and / or metallic iron; preferably the iron material comprises FeO and metallic iron; preferably the iron material comprises FeO; preferably the iron material comprises metallic iron.

3. A conical-bottomed fluidized bed reactor for producing metallic iron from ore using hot hydrogen, comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor.

4. The conical-bottomed fluidized bed reactor according to any one of claims 1 to 3, wherein the plurality of nozzles is provided in rows at different heights around the circumference of the cone; preferably a number of rows is two, three, or more.

5. The conical-bottomed fluidized bed reactor according to any one of claims 1 to 4, wherein the conical bottom presents an angle of about 65 degrees from the vertical.

6. The conical-bottomed fluidized bed reactor according to any one of claims 1 to 5, further comprising one or more pipes located at a top end of the reactor for removing unreacted hot hydrogen.

7. The conical-bottomed fluidized bed reactor according to any one of claims 1 to 6, further comprising at least one solid charge / discharge pipe located at a circumference of the reactor; preferably at a location different from the conical bottom.

8. A system for producing metallic iron from ore using hot hydrogen, comprising:a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor; and heating means for heating hydrogen, wherein the heating means comprises a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof; preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature.

9. A system for producing metallic iron from ore using hot hydrogen, comprising: a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor; and heating means for heating hydrogen, wherein the heating means involves electricity.

10. A system for producing metallic iron from ore using hot hydrogen, comprising: a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and one or more pipes located at a top end of the reactor for removing unreacted hot hydrogen; heating means for heating hydrogen, comprising a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof; preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature; and means for recycling the unreacted hot hydrogen for re-use.1 1 . A system for producing metallic iron from ore using hot hydrogen, comprising: a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and one or more pipes located at a top end of the reactor for removing unreacted hot hydrogen; heating means for heating hydrogen, wherein the heating means involves electricity; andmeans for recycling the unreacted hot hydrogen for re-use.

12. The system according to claim 10 or 11 , wherein the means for recycling comprises cooling means and condensation means.

13. The system according to any one of claims 8 to 12, further comprising means for preheating the ore prior to introduction into the reactor.

14. A process for producing metallic iron from ore using hot hydrogen, comprising: introducing ore into a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone; injecting the hot hydrogen into the reactor through the plurality of nozzles; and subjecting the ore to a reduction reaction thereby producing the metallic iron.

15. A process for producing metallic iron from ore using hot hydrogen, comprising: introducing ore into a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone, and one or more pipes located at a top end of the reactor; injecting the hot hydrogen into the reactor through the plurality of nozzles; subjecting the ore to a reduction reaction thereby producing the metallic iron; and removing unreacted hot hydrogen from the reactor through the one or more pipes; optionally the last three steps of the process are repeated a number of time until the reaction is completed.

16. A process for producing metallic iron from ore using hot hydrogen, comprising: introducing ore into a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone, and one or more pipes located at a top end of the reactor; injecting the hot hydrogen into the reactor through the plurality of nozzles; subjecting the ore to a reduction reaction thereby producing the metallic iron; removing unreacted hot hydrogen from the reactor through the one or more pipes; and subjecting the unreacted hot hydrogen to a recycling process; optionally the last four steps of the process are repeated a number of time until the reaction is completed.

17. The process according to claim 16, further comprising heating the recycled unreacted hydrogen then re-introducing same into the reactor through the nozzles; preferably an amount of water in the recycled hydrogen is less than an amount of water in the unreacted hot hydrogen; preferably an amount of water in the recycled hydrogen is below 0.3% or less.

18. The process according to any one of claims 14 to 17, wherein the hot hydrogen is obtained using heating means comprising a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof; preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature.

19. The process according to any one of claims 14 to 17, wherein the hot hydrogen is obtained using heating means involving electricity.

20. The process according to any one of claims 14 to 17, wherein a temperature of the hot hydrogen is about 900°C to about 1300°C; preferably at about 1000°C to about 1200°C.

21. The process according to any one of claims 14 to 20, wherein the ore is preheated prior to introduction into the reactor.

22. Use of hot hydrogen in a process for producing metallic iron from ore, comprising using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor.

23. Use of hot hydrogen in a process for producing metallic iron from ore, wherein the use comprises using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and wherein the use comprises use of heating means comprising a plasma torch, a Kanthal pipe heater, any other suitable heating element which allows for a decrease or elimination of greenhouse gas emissions, or a combination thereof;preferably the heating means includes means for generating a plasma with hydrogen; preferably the plasma with hydrogen is used for heating another flow of hydrogen which has a lower temperature.

24. Use of hot hydrogen in a process for producing metallic iron from ore, wherein the use comprises using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and wherein the use comprises use of heating means involving electricity.

25. Use of hot hydrogen in a process for producing metallic iron from ore, wherein the use comprises using a conical-bottomed fluidized bed reactor comprising a plurality of nozzles located at different heights around a circumference of the cone for introducing the hot hydrogen into the reactor, and wherein the use comprises removing unreacted hot hydrogen from the reactor and recycling the unreacted hot hydrogen for re-use.

26. A plant for producing of metallic iron from ore using hot hydrogen, the plant embodying the conical-bottomed fluidized bed reactor as defined in any one of claims 1 to 7, the system as defined in any one of claims 8 to 12, the process as defined in any one of claims 14 to 21 , and / or the use as defined in any one of claims 22 to 25.

27. The conical-bottomed fluidized bed reactor as defined in any one of claims 1 to 7, the system as defined in any one of claims 8 to 12, the process as defined in any one of claims 14 to 21 , the use as defined in any one of claims 22 to 25, or the plant as defined in claim 26, wherein ore is ilmenite ore or any other ore material comprising iron oxides such as hematite, magnetite, etc.