Method and system for producing high-quality synthesis gas for producing direct reduced iron (DRI) while maintaining high energy efficiency

Abstract

A method and system of producing a synthesis gas for producing direct reduced iron in a direct reduction shaft furnace, including: preheating a cold feed gas in a heater to form a hot feed gas; adding preheated external hydrogen to the hot feed gas downstream of the heater; feeding the hot feed gas and the preheated external hydrogen added to the hot feed gas to a reformer; and reforming the hot feed gas and the preheated external hydrogen added to the hot feed gas in the reformer to form the synthesis gas. The method and system further include: feeding the synthesis gas to an annular bustle of the direct reduction shaft furnace for producing direct reduced iron in the direct reduction shaft furnace. The method can include: adding preheated external hydrogen to the synthesis gas downstream of the reformer and upstream of the direct reduction shaft furnace.

Description

[0001] Cross-reference to related applications

[0002] This disclosure claims priority to co-pending U.S. Provisional Patent Application No. 63 / 599,673, filed November 16, 2023, entitled “METHODS AND SYSTEMS TOPRODUCE HIGH QUALITY SYNGAS FOR THE PRODUCTION OF DIRECT REDUCED IRON (DRI) WHILE MAINTAINING HIGH ENERGY EFFICIENCY,” the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure generally relates to the fields of direct reduced iron (DRI) and steelmaking, and particularly to process efficiency and facility operability. More specifically, this disclosure relates to methods and systems for producing high-quality syngas for DRI production while maintaining high energy efficiency. Background Technology

[0004] DRI (often referred to as sponge iron) is typically produced in moving bed or shaft furnace reactors by reacting iron ore with a reactive gas stream containing reducing agents such as H2 and CO. Such DRI products can be used as a source of low residual iron (in addition to scrap iron and pig iron) in steel production (primarily through electric arc furnaces (EAFs) in steelmaking facilities).

[0005] DRI is a high-quality ore-based metal (OBM) raw material used in the manufacture of a wide variety of steel products. For example... Figure 1 As shown, in a direct reduction (DR) process such as the Midrex® (Kobe Steel, Ltd.) process, iron oxide is reduced to DRI in a shaft furnace 11 of DR facility 10 using thermal reducing gases (such as H2 and CO). The top gas 1, containing reduction products (such as H2O and CO2) and entrained reactants (such as H2 and CO), is treated by a top gas scrubber 12 to remove dust and lower the temperature of the top gas 1, which helps control the H2O content in the top gas 1. Approximately one-third of the scrubbed gas is discharged and introduced into reformer 17 as fuel for that reformer 17 (i.e., top gas fuel) 3. The combustion products are then discharged from facility 10 via flue gas chimney 14. The remaining scrubbed gas 2 is directed to one or more compressors 13. The resulting compressed gas 4 is mixed with natural gas C. N H 2N+2(NG) 5 is mixed and then directed to reformer 17 for reuse.

[0006] Typically, the gas mixture 6 (compressed gas 4 and NG 5) is preheated using a tubular heat exchanger 15 before being directed to the reformer 17, which reduces the heat load on the reformer 17. Similarly, the combustion air supplied by the blower 16 can be preheated using a tubular heat exchanger 26.

[0007] The preheated gas mixture leaving the tubular heat exchanger 15 is referred to as feed gas 7. In the reformer 17, the C in feed gas 7... N H 2N+2 H2O and CO2 are reformed into CO and H2 (as shown in the reaction equation below), while the CO and H2 entrained in the top gas 1 are heated as it passes through reformer 17. The hot reformed gas 8 is then directed into the DR shaft furnace 11, where it is used to reduce iron oxide in an upward flow. Due to the volume expansion of the gas during the reforming reaction, the top gas fuel 3 is discharged from the recirculation circuit 9 at the outlet of the top gas scrubber 12.

[0008] (1)

[0009] (2)

[0010] As a tubular reformer, reformer 17 includes a catalyst-packed bed inside a reforming tube through which the feed gas 7 flows, while the outside of the reforming tube is externally heated by a burner. The reformed gas 8 leaving reformer 17 is close to equilibrium, and the performance of reformer 17 is primarily limited by the amount of heat transferred to the feed gas 7 in the reforming tube.

[0011] As part of global efforts to combat climate change, the steel industry seeks to reduce or eliminate its CO2 emissions. In conventional steelmaking, the largest share of CO2 emissions originates during the reduction phase of iron ore, where iron oxide is reduced to metallic iron using coal in the case of a blast furnace and NG in the case of a DR furnace. The input of fossil fuels is used not only to provide the chemicals required for reduction but also to supply the energy needed to drive the reaction. In the case of DR, it has been determined that hydrogen produced from green sources can be used as a substitute for NG, thereby significantly mitigating emissions during the reduction phase of steelmaking. For this reason, recent Midrex® DR facilities have been designed to be able to replace natural gas with a flexible amount of H2 based on H2 availability (C N H 2N+1 This requires operational flexibility to withstand a wider range of operating conditions with variable substitution rates through H2, as addressed by existing U.S. Patent Application Publication No. 2021 / 0095354.

[0012] Therefore, current advanced technologies include the use of heat recovery (HR), which involves... Figure 1 Downstream of the Midrex® reformer 17, a tubular heat exchanger 15 is used to improve the overall DR energy efficiency. Furthermore, the HR allows for increased syngas production within the reformer 17 and helps avoid unwanted side reactions such as carbon buildup.

[0013] However, the problem encountered is that conventional reformers 17 typically operate under a relatively narrow range of operating conditions. In these conditions, it is necessary to replace the C with externally supplied H2 gas. N H 2N+1 To avoid CO2 emissions, the gas composition and flow rate can change significantly. Since the HR system has a fixed heat transfer area, these changes in gas composition and flow rate reduce the HR's efficiency. Then, when the feed gas flow rate and flue gas flow rate change, the temperature of the preheated feed gas 7 decreases. This reduces the overall facility energy efficiency and also causes a reduction in syngas production in reformer 17. Furthermore, the lower temperature promotes carbon buildup through the Boudouard carbon reaction. The Boudouard carbon reaction can rapidly destroy the catalyst in reformer 17, leading to equipment damage and DRI production loss.

[0014] Therefore, there remains a need in the field for DR methods and systems that can produce high-quality syngas for DRI production while maintaining high energy efficiency and avoiding unwanted and harmful side reactions. Summary of the Invention

[0015] The implementation of this disclosure addresses the aforementioned and other needs, and improves existing methods, systems, and practices for producing syngas for DRI production.

[0016] The embodiments of this disclosure address the aforementioned problems by directly introducing preheated H2 gas into the hot feed gas (HFG), which has been preheated using HR and subsequently introduced into the reformer. Embodiments of the invention are particularly advantageous when H2 gas is supplied at a rate exceeding 30% and up to 100% of the total process fuel.

[0017] Therefore, according to the embodiments, this disclosure provides a method and system for producing reformed gas (syngas) for DR of iron oxide, wherein a stoichiometric reformer is used to produce the reformed gas, and the feed gas is preheated with HR before the reformer to recover heat from the reformer flue gas (combustion products), and the DR process operates continuously with a full range of external fuel sources (from 100% NG to 100% hydrogen).

[0018] In some implementations, feed gas preheating is maintained above approximately 500°C and above 40% hydrogen, regardless of external fuel operating conditions, as measured as the ratio of total net effective heat input of hydrogen to total process gaseous fuel requirements.

[0019] In some embodiments, the externally supplied hydrogen is heated to above about 500°C, and preferably up to about 1000°C.

[0020] In some implementations, externally supplied hydrogen is introduced into the process downstream of the HR and upstream of the reformer to maintain the feed gas preheating temperature above about 500°C and preferably up to about 700°C.

[0021] In some implementations, an additional option is to inject the aforementioned preheated hydrogen into the reformate (after the hydrogen has been preheated to at least about 700°C and preferably up to about 900°C).

[0022] In some implementations, as an additional option, the hydrogen is preheated to at least about 700°C and preferably up to about 900°C by an electric heater.

[0023] In some implementations, as an additional option, hydrogen is preheated to at least about 700°C and preferably up to about 900°C using green electricity.

[0024] In some embodiments, this disclosure provides a method for producing syngas for producing direct reduced iron (DRI) in a direct reduction shaft furnace. The method includes: preheating a cold feed gas in a heater to form a hot feed gas; adding preheated external hydrogen to the hot feed gas downstream of the heater; feeding the hot feed gas and the preheated external hydrogen added to the hot feed gas into a reformer; and reforming the hot feed gas and the preheated external hydrogen added to the hot feed gas in the reformer to form syngas. The method also includes feeding the syngas into an annular tuyer (bustle) of the direct reduction shaft furnace for producing DRI within the furnace.

[0025] In some embodiments, the method includes adding preheated external hydrogen to the syngas downstream of the reformer and upstream of the direct reduction shaft furnace. Both the preheated external hydrogen added to the hot feed gas and the preheated external hydrogen added to the syngas can be derived from an external hydrogen source and preheated using an external heater. The external heater can be a combustion heater, an electric heater, or an electric heater utilizing a green power source.

[0026] The cold feed gas can be top gas, which is taken from the direct reduction shaft furnace and subjected to dust removal / cooling and compression upstream of the heater.

[0027] The heater can be a heat recovery component that uses flue gas from the reformer to preheat the cold feed gas to form a hot feed gas.

[0028] In some embodiments, the hot feed gas has a temperature above 500°C, the preheated external hydrogen added to the hot feed gas has a temperature above 500°C, and the preheated external hydrogen added to the synthesis gas has a temperature above 700°C.

[0029] In some embodiments, this disclosure provides a system for producing syngas for producing direct reduced iron in a direct reduction shaft furnace. The system includes: a heater for preheating cold feed gas to form hot feed gas; an external hydrogen source and an external heater for adding preheated external hydrogen to the hot feed gas downstream of the heater; and a reformer for receiving the hot feed gas and the preheated external hydrogen added to the hot feed gas, and reforming the hot feed gas and the preheated external hydrogen added to the hot feed gas to form syngas. The system also includes an annular duct for the direct reduction shaft furnace for receiving the syngas used in the production of direct reduced iron.

[0030] In some embodiments, the system includes an external hydrogen source and an external heater for adding preheated external hydrogen to the syngas downstream of the reformer and upstream of the direct reduction shaft furnace. The external hydrogen source and external heater for adding the preheated external hydrogen to the hot feed gas and the external hydrogen source and external heater for adding the preheated external hydrogen to the syngas can be the same external hydrogen source and the same external heater. The external heater can be a combustion heater, an electric heater, or an electric heater utilizing a green power source.

[0031] The cold feed gas can be top gas, which is taken from the direct reduction shaft furnace and subjected to dust removal / cooling and compression upstream of the heater.

[0032] The heater can be a heat recovery component that uses flue gas from the reformer to preheat the cold feed gas to form a hot feed gas.

[0033] In some embodiments, the hot feed gas has a temperature above 500°C, the preheated external hydrogen added to the hot feed gas has a temperature above 500°C, and the preheated external hydrogen added to the synthesis gas has a temperature above 700°C. Attached Figure Description

[0034] The present disclosure has been illustrated and described with reference to the accompanying drawings, wherein any like reference numerals are used where appropriate to denote the same system / component parts or method steps, and wherein:

[0035] Figure 1 This is a schematic diagram illustrating the operation of the DR facility;

[0036] Figure 2 This is a schematic diagram of a DR process / system in which external H2 gas is supplied directly to the syngas leaving the reformer;

[0037] Figure 3 This diagram illustrates a DR process / system in which preheated H2 gas is directly introduced into a hot feed gas (HFG) that is preheated by HR and then introduced into the reformer; and;

[0038] Figure 4 This diagram illustrates a DR process / system in which preheated H2 gas is directly introduced into the reforming gas pipeline and into the HFG; and

[0039] Figure 5 This is a flowchart illustrating one embodiment of the DR method / process of this disclosure. Detailed Implementation

[0040] The embodiments of this disclosure advantageously improve upon existing methods and systems, producing high-quality syngas for DRI production while maintaining high energy efficiency. According to the embodiments, by directly introducing preheated H2 gas into the HFG (which has been preheated with HR and then introduced into the reformer), the total burner heat load is reduced, thereby significantly improving reformer operating costs and efficiency.

[0041] Similarly, the embodiments of this disclosure solve the problems in the prior art by directly introducing preheated H2 gas into the HFG (which has been preheated with HR and then introduced into the reformer); and according to the embodiments of this disclosure, such embodiments are particularly suitable and advantageous when H2 gas accounts for more than 30% and up to 100% of the total process fuel.

[0042] Therefore, according to the embodiments, this disclosure provides a method and system for producing reformed gas (syngas) for DR of iron oxide, wherein a stoichiometric reformer is used to produce the reformed gas, and the feed gas is preheated by HR before the reformer to recover heat from the reformer flue gas (combustion products), and the DR process operates continuously with a full range of external fuel sources (from 100% NG to 100% hydrogen).

[0043] H2 gas can be preheated by any conventional or suitable method, such as combustion. For example, H2 gas can be heated electrically in a temperature range of about 500°C to about 1000°C and then injected into the HFG to control or maintain the temperature above about 550°C and below about 700°C. This range advantageously allows for simplified HR design while maintaining high reformer capacity. Heating H2 gas with electricity or green electricity reduces CO2 emissions compared to hydrocarbon combustion. However, significant operating cost savings can also be achieved compared to expensive H2 combustion preheating technologies used for preheating H2 gas. Examples of green electricity include electricity from resources and facilities such as wind, biomass, solar, geothermal, or others.

[0044] In conventional reformers, hydrogen is typically not introduced into the feed gas. This is because hydrogen is a product of the reforming reaction. Adding a product (hydrogen) to the feed gas, as described herein, is surprising and counterintuitive, because, for example, a higher product concentration in the feed gas would weaken the equilibrium driving force for the reforming reaction, leading to lower conversion rates and reduced reformed gas quality. However, tests have advantageously determined and verified that any negative effects can be satisfactorily and advantageously overcome by maintaining a sufficiently high feed gas preheating temperature as described above.

[0045] Another feature of the embodiments of this disclosure is that, in certain situations, reformer operating costs can be significantly improved because the total burner heat load is reduced through an additional heater. This advantageously avoids the use of expensive H2 gas and its introduction into the reformer burner. If the heater is electrically powered, H2 usage in the burner is reduced. For combustion-type heaters, the reduced heat load in the burner does not result in a significant change in fuel consumption.

[0046] Another advantageous embodiment of this disclosure also achieves additional improvements in the operation of the DR facility by directing preheated hydrogen downstream of the reformer into the reformer pipeline.

[0047] In conventional technologies, the amount of hydrogen introduced into the reformer line is limited by the requirement that a sufficiently high temperature (above approximately 800°C) be maintained at the annular duct of the DR shaft furnace to allow the reduction reaction to occur and to maintain a high furnace productivity. Hydrogen can be used directly in the reformer, but if the temperature is not high enough, there will not be sufficient energy to support the reduction reaction. An additional advantage of embodiments of this disclosure is that hydrogen can be heated to a sufficiently high temperature (above approximately 800°C), allowing it to be used directly in the reformer without the disadvantage of lowering the reformer temperature. External hydrogen heating also reduces the need to maintain the annular duct gas temperature (when...). Figure 1The amount of oxygen injected (when used in the process) is reduced, resulting in additional operating cost savings.

[0048] Now for reference Figure 2 It illustrates a DR process / system 20 in which external H2 gas 18 is directly supplied to the synthesis gas 8; including C N H 2N+1 The feed gas 7, consisting of CO2 and H2O, is processed via reformer 17 to produce syngas 8. Specifically, cold feed gas 6 enters HR assembly 19 (including heat exchanger 15 and / or other preheating tube bundles or burners 21, such as air, top gas feed (TGF), NG, etc.), and is preheated therein. This HR assembly 19 utilizes flue gas 22 and exhaust gas 23 from reformer 17. The preheated mixture exits HR assembly 19 as preheated feed gas 7 and enters reformer 17. In reformer 17, the CO2 in feed gas 7 is... N H 2N+2 H2O and CO2 are reformed into CO and H2. The hot reformed gas 8 is then guided to the DR vertical furnace 11.

[0049] It should be noted that the temperature of HFG 7 needs to be maintained high enough, otherwise the chemical properties of the syngas 8 will be adversely affected. Furthermore, with the injection of more external H2 gas 18, the flow rate of flue gas 22 will decrease and the HFG temperature will become lower. If the temperature is too low, the chemical properties of the syngas will again be adversely affected, and undesirable carbon deposits may occur in the reformer 17. Therefore, the following... Figure 3 These problems are advantageously further addressed, and it should be noted that external H2 gas 18 supplied directly to syngas 8 can be used in all implementation schemes.

[0050] Now for reference Figure 3 ,and Figure 2 Similarly, one embodiment of the DR process / system 30 for producing high-quality syngas 8 for DRI production, as disclosed herein, includes processing a feed gas 7 containing CH4, CO2, and H2O via a reformer 17 to produce syngas 8 containing H2 and CO. Here, a cold feed gas 6 enters an HR assembly 19 (including a heat exchanger 15 and / or other preheating tube bundles or burners 21, such as air, TGF, NG, etc.), and is preheated therein to form HFG 7. This HR assembly 19 reuses flue gas 22 and exhaust gas 23 from the reformer 17. The preheated gas mixture exits the HR assembly 19 as preheated feed gas 7 and enters the reformer 17. Figure 3As shown, external H2 gas 24 is preheated to above about 500°C, such as about 700°C to about 1000°C, by combustion or electric heating using heater 25, and this preheated H2 gas 24 is directly injected into the preheated feed gas (HFG 7) between HR assembly 19 and reformer 17.

[0051] Due to the increased temperature (preheating) of H2 gas 24, the preheated H2 gas 24 can advantageously be directly injected into HFG 7, and then subsequently enters reformer 17. The hot reformed gas 8 is then directed to DR shaft furnace 11. Advantageously, high-quality syngas 8 for DRI production is produced while maintaining high energy efficiency. It should be noted that, due to relevant chemical limitations, prior art could not achieve this using existing technology. Figure 3 Cold H2 gas 24 is introduced at the location shown.

[0052] Figure 4 This is a schematic diagram illustrating one embodiment of the DR process / system 40 of this disclosure (similar to...). Figure 3 Furthermore, the preheated H2 gas 24 is also directly introduced into the reforming gas pipeline 8.

[0053] Therefore, according to the implementation plan, a method and system for producing reformed gas (syngas) for DR of iron oxide is disclosed, wherein a stoichiometric reformer is used to produce the reformed gas, and the relevant feed gas is preheated before the reformer, and after being dusted and compressed, heat is recovered from the reformer flue gas (combustion products) using HR, and the DR process operates continuously with a full range of external fuel sources (from 100% NG to 100% hydrogen).

[0054] In some implementations, regardless of external fuel operating conditions, but preferably, the feed gas preheating is maintained at above about 500°C under conditions of more than 40% hydrogen (which is measured as the ratio of total net available heat input of hydrogen to total process gaseous fuel requirements).

[0055] In some embodiments, the externally supplied hydrogen is heated to above about 500°C, and preferably up to about 1000°C.

[0056] In some implementations, externally supplied hydrogen is introduced into the process downstream of the feed gas HR unit and upstream of the reformer to maintain the feed gas preheating temperature above about 500°C, and preferably up to about 700°C.

[0057] In some implementations, an additional option is to inject the preheated hydrogen into the reformate after the aforementioned hydrogen has been preheated to at least about 700°C and preferably up to about 900°C.

[0058] In some implementations, as an additional option, the hydrogen is preheated to at least about 700°C and preferably up to about 900°C by an electric heater.

[0059] In some implementations, as an additional option, hydrogen is preheated to at least about 700°C and preferably up to about 900°C using green electricity.

[0060] Figure 5 This is a flowchart illustrating one embodiment of the DR method / process 50 of this disclosure. According to method 50, at step 51, a cold feed gas, optionally composed of top gas, is fed into a heater derived from the DR shaft furnace and subjected to dust removal / cooling and compression. This heater comprises an HR assembly (such as, for example, a heat exchanger and / or other preheating tube bundles or burners, such as air, TGF, NG, etc.). This HR assembly utilizes flue gas and exhaust gas from the reformer. The preheated gas mixture exits the HR assembly as an HFG having a temperature above about 500°C and preferably up to about 700°C. At step 52, at this point in the process, external hydrogen is injected into the HFG after being preheated to a temperature above about 500°C and preferably up to about 1000°C using a combustion heater or an electric heater (optionally using green electricity). At step 53, the mixture of the HFG and the preheated external hydrogen is introduced into the reformer and reformed to form reformed gas or synthesis gas. At step 54, the reforming gas or syngas may be mixed with a portion of the preheated external hydrogen mentioned above or from another external source (at a temperature of at least about 700°C and preferably up to about 900°C). At step 55, the final reforming gas or syngas is introduced into the annular duct of the DR shaft furnace and used to reduce the iron oxide therein.

[0061] As noted above, the temperature of the HFG needs to be maintained at a sufficiently high level; otherwise, the chemical properties of the reformed gas or syngas will be adversely affected. Furthermore, with the injection of more external H2 gas after the reformer, the flow rate of the flue gas fed into the HR assembly decreases, and the HFG temperature becomes lower. If the temperature is too low, the chemical properties of the reformed gas or syngas will again be adversely affected, and unsuitable carbon deposition may occur in the reformer. Therefore, this disclosure advantageously solves these problems by injecting preheated hydrogen into the HFG between the HR assembly and the reformer, and optionally also by injecting preheated hydrogen into the HFG downstream of the reformer.

[0062] Although this disclosure has been illustrated and described with reference to particular embodiments and specific examples thereof, it will be apparent to those skilled in the art that other embodiments and examples can perform similar functions and / or achieve the same results. All such equivalent embodiments and examples are considered within the spirit and scope of this disclosure and are intended to be covered by the appended non-limiting claims for all purposes. Furthermore, all described embodiments, elements, limitations, and features can be used in any combination.

Claims

1. A method for producing syngas for producing direct reduced iron in a direct reduction shaft furnace, the method comprising: The cold feed gas is preheated in a heater to form hot feed gas; Preheated external hydrogen is added to the hot feed gas downstream of the heater; The hot feed gas and the preheated external hydrogen added to the hot feed gas are fed into the reformer. as well as In the reformer, the hot feed gas and the preheated external hydrogen added to the hot feed gas are reformed to form the synthesis gas.

2. The method according to claim 1, further comprising: The syngas is fed into the annular duct of the direct reduction shaft furnace for the production of direct reduced iron in the direct reduction shaft furnace.

3. The method according to claim 2, further comprising: Preheated external hydrogen is added to the syngas downstream of the reformer and upstream of the direct reduction shaft furnace.

4. The method of claim 3, wherein the preheated external hydrogen added to the hot feed gas and the preheated external hydrogen added to the synthesis gas both originate from an external hydrogen source and are preheated using an external heater.

5. The method of claim 4, wherein the external heater comprises one of a combustion heater, an electric heater, and an electric heater utilizing a green power source.

6. The method of claim 1, wherein the cold feed gas comprises top gas taken from the direct reduction shaft furnace and subjected to dust removal / cooling and compression upstream of the heater.

7. The method of claim 1, wherein the heater includes a heat recovery assembly that uses flue gas from the reformer to preheat the cold feed gas to form the hot feed gas.

8. The method of claim 1, wherein the hot feed gas has a temperature above 500°C at the reformer.

9. The method of claim 1, wherein the preheated external hydrogen added to the hot feed gas has a temperature above 500°C.

10. The method of claim 3, wherein the preheated external hydrogen added to the synthesis gas has a temperature above 700°C.

11. A system for producing syngas for producing direct reduced iron in a direct reduction shaft furnace, the system comprising: A heater, used to preheat cold feed gas to form hot feed gas; An external hydrogen source and an external heater, which are used to add preheated external hydrogen to the hot feed gas downstream of the heater; as well as A reformer for receiving the hot feed gas and the preheated external hydrogen added to the hot feed gas, and for reforming the hot feed gas and the preheated external hydrogen added to the hot feed gas to form the synthesis gas.

12. The system of claim 11, further comprising an annular duct for receiving the synthesis gas for producing the direct reduced iron.

13. The system of claim 12, further comprising an external hydrogen source and an external heater for adding preheated external hydrogen to the syngas downstream of the reformer and upstream of the direct reduction shaft furnace.

14. The system of claim 13, wherein the external hydrogen source and the external heater for adding the preheated external hydrogen to the hot feed gas, and the external hydrogen source and the external heater for adding the preheated external hydrogen to the synthesis gas, are the same external hydrogen source and the same external heater.

15. The system of claim 11, wherein the external heater comprises one of a combustion heater, an electric heater, and an electric heater utilizing a green power source.

16. The system of claim 11, wherein the cold feed gas comprises top gas taken from the direct reduction shaft furnace and subjected to dust removal / cooling and compression upstream of the heater.

17. The system of claim 11, wherein the heater includes a heat recovery assembly that uses flue gas from the reformer to preheat the cold feed gas to form the hot feed gas.

18. The system of claim 11, wherein the hot feed gas has a temperature above 500°C at the reformer.

19. The system of claim 11, wherein the preheated external hydrogen added to the hot feed gas has a temperature above 500°C.

20. The system of claim 13, wherein the preheated external hydrogen added to the synthesis gas has a temperature above 700°C.

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